Chapter V: Environmental Consequences

Introduction

The National Environmental Policy Act (NEPA) requires that environmental documents disclose the environmental impacts of a proposed federal action, reasonable alternatives to that action, and any adverse environmental effects that cannot be avoided should the proposed action be implemented. This chapter analyzes the environmental impacts of the four Merced Wild and Scenic River Revised Comprehensive Management Plan and Supplemental Environmental Impact Statement (Revised Merced River Plan/SEIS) alternatives on natural resources, cultural resources, the visitor experience, and social resources. This analysis provides the basis for comparing the beneficial and adverse effects of the alternatives.

In compliance with NEPA, the environmental analysis evaluates the potential effects of the alternatives on all of the park's natural, cultural, visitor experience, and social resources, including those not encompassed within the Outstandingly Remarkable Values (ORVs). However, since this document must comply with the requirements of the Wild and Scenic Rivers Act, the potential effects of the alternatives on the ORVs for each segment are addressed in the resource analysis. In addition, how each alternative protects and enhances the ORVs under the Wild and Scenic Rivers Act is summarized in the tables at the end of the analysis section for each alternative.

This analysis only addresses environmental consequences associated with the development and implementation of a user capacity program for the Merced River corridor and the reassessment of the river corridor boundary based on the location of ORVs and related management zoning prescriptions in the El Portal segment. The remaining management elements as previously described and analyzed in the Merced River Plan/FEIS are not being revisited or reanalyzed in this Plan.

Due to the conceptual nature of the alternatives, their potential consequences can be addressed only in qualitative terms. The conclusions presented herein are based on review of existing information provided by the National Park Service. If and when specific National Park Service management actions are proposed as a result of this plan, National Park Service staff will determine whether more detailed environmental documentation is required, consistent with the provisions of NEPA.

Following this introduction, Chapter V presents the methodologies used in the environmental impact analysis. The impact analyses sections are organized by alternative. The first section analyzes Alternative 1 (the No Action Alternative), including impacts on natural resources, cultural resources, the visitor experience, and social resources and presents mitigation measures, cumulative impacts, and impact conclusions. The same framework of analyses is applied to Alternatives 2, 3, and 4 in subsequent sections. Environmental impacts are summarized in table III-12 at the end of Chapter III.

Cumulative Impacts

A cumulative impact is described in regulations developed by the Council on Environmental Quality (CEQ), regulation 1508.7, as follows:

". . . a "Cumulative impact" is the impact on the environment which results from the incremental impact of the action when added to other past, present, and reasonably foreseeable future actions regardless of what agency (Federal or non-Federal) or person undertakes such other actions. Cumulative impacts can result from individually minor but collectively significant actions taking place over a period of time."

Appendix E contains the list of past, present, and reasonably foreseeable actions included in the cumulative impacts analysis. These cumulative actions are evaluated in the impact analysis in conjunction with the impacts of an alternative to determine whether they would have any additive effects on a particular natural, cultural, or social resource. Because many of these cumulative actions are in the early planning stages, the evaluation of cumulative impacts was based on a general description of each project.

The Revised Merced River Plan/SEIS is a programmatic document and does not recommend implementation of specific large-scale construction or development related actions. As a result, the cumulative impacts analysis is presented in qualitative terms, rather than in specific measured or quantitative terms. General guidance and methodologies for the cumulative impacts analysis in this document follow those published by the CEQ (CEQ 1997). Cumulative impacts have been analyzed for each alternative, and can be found following the environmental consequences analysis for each resource topic. The methodology for defining the context, intensity, duration and type of cumulative impact for a specific resource topic is the same as that described for the environmental consequences analysis of each resource topic.

Impairment

Impairment is an impact that, in the professional judgment of the responsible National Park Service manager, would harm the integrity of park resources or values, including the opportunities that otherwise would be present for the enjoyment of those resources or values. The need to analyze and disclose impairment impacts originates from the 1916 Organic Act, which mandated the National Park Service "to conserve the scenery and the natural and historic objects and the wild life therein and to provide for the enjoyment of the same in such manner and by such means as will leave them unimpaired for the enjoyment of future generations."

An impact would be less likely to constitute impairment if it is an unavoidable result (which cannot reasonably be further mitigated) of an action necessary to preserve or restore the integrity of park resources or values (NPS 2000c). An impact would be more likely to constitute impairment to the extent that it affects a resource or value whose conservation is:

·       Necessary to fulfill specific purposes identified in the establishing legislation or proclamation of the park

·       Key to the natural or cultural integrity of the park or to opportunities for enjoyment of the park

·       Identified as a goal in the park's General Management Plan (NPS 1980a) or other relevant National Park Service planning documents

Impairment of park resources was evaluated on the basis of the type and intensity of impacts, and in terms of the types of resources affected. Impairment is generally considered for natural, cultural, and scenic resources. Overall, beneficial impacts would not constitute impairment. With respect to the intensity of impacts, negligible and minor adverse impacts are not of sufficient magnitude to constitute impairment. Moderate and major adverse impacts may constitute impairment, but not automatically. Rather, these impacts must be analyzed with respect to the three criteria presented above. Impairment is generally considered for geological, hydrological, biological, cultural, and scenic resources. Impairment determinations are not required for resource topics that are not considered to be park resources or values. Thus, impairment is addressed in the conclusion section of the appropriate resource topics under each alternative.

Methodologies

This section presents the methodologies used to conduct the environmental impact analyses. The section begins by describing methodologies and assumptions common to all resource topic areas, and then presents methodologies specific to individual resource topic areas in the following order:

Natural Resources: Geology, Geohazards, and Soils; Hydrology, Water Quality, and Floodplains; Wetlands; Vegetation; Wildlife; Rare, Threatened, and Endangered Species; Air Quality; and Noise

Cultural Resources: Archeological Resources; Traditional Cultural Resources; and Historic Sites, Structures, and Landscapes

Visitor Experience: Recreation; Interpretation and Orientation; Visitor Services; and Wilderness Experience

Social Resources: Land Use; Transportation; Scenic Resources; Socioeconomics; and Park Operations and Facilities

Each resource topic area includes a discussion of the impacts of each alternative, including the identification of the impacts or affects of the actions comprising the alternative, and a characterization of the impacts in terms of context, intensity, duration, and type of impact. The context of the impact considers whether the impact would be local or regional. The intensity of the impact refers to the severity or magnitude of the impact, and considers whether the impact would be negligible, minor, moderate, or major. The duration of the impact considers whether the impact would occur in the short term (temporary) or the long term (permanent). The type of impact considers whether the impact would be beneficial or adverse to the natural, cultural, or social environment.

Annual park visitation peaked at just over 4.19 million visitors in 1996. Park visitation decreased from 1996 through 2004 to approximately 3.39 million visitors annually. However, for the purposes of this analysis, it is expected that overall park visitation will increase slowly over the next 15 years under existing park management policies (the No Action Alternative). Although it is not known how much annual visitation would increase by 2020, it is expected that increased visitation during peak periods would require implementation of restricted access to Yosemite Valley during some peak visitation periods. Increased visitation demand by 2020 would be expected to trigger the need to implement restricted access on an increasing number of days during the peak season, and it is expected that there would be more restricted access days in 2020 than is currently experienced. Increases in 2020 visitation levels would be expected to occur primarily during the current non-peak periods (e.g., before and after peak summer months, and on weekdays during peak summer months).

With the implementation of a VERP program and possibly limits, some of the alternatives could result in decreased visitation to segments of the Merced River corridor. As a result, it is assumed that by 2020 some visitors could be displaced to other areas of the park or displaced from the park itself.

This document is a programmatic plan that looks at broad user capacity program frameworks. The plan does not recommend implementation of specific developments or actions. To provide decision makers and the public with an accurate idea of the environmental consequences of the Revised Merced River Plan/SEIS alternatives, the analysis team identified potential actions that management could implement under the frameworks provided under each of the action alternatives and analyzed their effects as compared to conditions under the No Action Alternative. The environmental consequences analyses are qualitative rather than quantitative, because the action alternatives are conceptual and specific actions are not prescribed under this plan.

The environmental consequences analysis in this chapter evaluates the potential effects of implementation of various types of management actions. Because implementation of VERP would allow for park management to use a variety of management tools to address user-related impacts, the analysis evaluates the potential effects of a broad range of actions - from public education to construction of improvements to visitor access restrictions. In reality, implementation of the VERP program would likely result in the implementation of a number of these measures, as determined to be appropriate based on site-specific circumstances. VERP is an adaptive management process, and management actions would change and evolve based on the continued monitoring of actual conditions versus desired conditions. Thus, if VERP monitoring indicated there was a yellow light condition (see figure II-6 in Chapter II), park management could begin implementing measures such as public education, installation of temporary barriers, or other easily management actions to bring conditions back within standards. If conditions were to continue to decline, park management would most likely implement additional, more restrictive or intensive measures to address the impacts. Because the VERP program requires park management to take actions to keep conditions within adopted standards, or to improve conditions that do not meet the standards, park management would continue to implement a variety of measures as needed to meet the adopted standard. Therefore, although the effects of individual management actions taken in the short term are identified in each section, the overall effect of the VERP component of the action alternatives would be to protect and enhance the condition of park resources and ORVs in the long term.

Finally, the No Action Alternative for the Revised Merced River Plan/SEIS includes the implementation of all of the elements of the Merced River Plan (with the exception of VERP), as well as implementation of other existing user capacity measures described in Chapter II, such as the trailhead quota system and facility limits. Although each of the action alternatives also includes implementation of the Merced River Plan elements and the user capacity program as described under the No Action Alternative, the analysis in this chapter focuses on the effects of implementing the additional user capacity elements of each action alternative (VERP, limits) compared to the No Action Alternative.

Natural Resources

Geology, Geohazards, and Soils

This impact assessment focused on effects that geologic processes in the Yosemite National Park would have on visitors, employees, and facilities under each alternative of the Revised Merced River Plan/SEIS. Geologic processes can negatively affect visitors, employees, and facilities when events such as rockfalls, earthquakes, and severe soil instability result in injury, death, or damage to facilities.[1] The assessment also focused on the effect the Revised Merced River Plan/SEIS alternatives would have on the geologic processes, namely, the formation and conservation of soil resources. Impacts associated with management actions discussed in this Revised Merced River Plan/SEIS could affect current soil resources through accelerated erosion, soil loss, or soil removal.

Several assumptions regarding facility placement, geologic design parameters, and public safety were integrated into this assessment, as summarized below.

·       It is not possible to avoid risks due to geologic processes such as earthquakes and rockfalls. Considering this, some facilities located within the park, especially in Yosemite Valley, the Merced River gorge, and El Portal would be exposed to risks of damage from rockfalls.

·       Geotechnical studies to determine soil stability conditions would be performed prior to placing, designing, or relocating a facility within the park, and facility design within Yosemite National Park would conform to accepted building codes regarding seismic design parameters.

·       In emergency situations, the National Park Service may mechanically trigger a rockfall, but in most cases the National Park Service allows natural processes to occur unimpeded.

·       The National Park Service has developed geologic hazard guidelines for development within Yosemite Valley (Appendix C in NPS 2000e). The focus of these guidelines is to protect visitors, employees, and infrastructure from geologic hazards and to locate facilities out of geologically hazardous areas.

·       In the event of a rockfall, the National Park Service would close the affected area to protect visitor and employee safety. Rocks on roads would be removed, but rockfall talus in rivers would not be removed, unless the river is dammed and flooding threatens utilities or facilities.

Geologic risks that affect public safety are rarely predictable, and the extent to which they can affect people and property cannot be quantified. Quantitative analysis of other potential effects, such as soil erosion, removal, and loss was not feasible for this impact assessment due to the programmatic nature of the plan. Rather, analysis of effects was qualitative, and professional judgment has been applied to reach reasonable conclusions as to the context, intensity, and duration of potential impacts. When possible, mitigation measure(s) were incorporated into this Revised Merced River Plan/SEIS to reduce the intensity of adverse effects.

Impact Assessment

The impact assessment addressed geologic hazards (earthquakes and rockfalls) and impacts to soil resources. Geologic hazards that would expose people to injury and infrastructure to damage were considered in terms of impacts to public safety. Geologic impacts related to facility development or natural resource protection were considered in terms of depletion of or adverse effects on soil resources. Potential management actions under each alternative were evaluated in terms of the context, intensity, and duration of the geologic impacts, and whether the impacts were considered to be beneficial or adverse to visitors, infrastructure, or soil resources.

Context. The context of the impact considers whether the impact would be local or regional. For the purposes of this analysis, local impacts would be those that occur within Yosemite National Park or impacts specific to the river corridor, including the El Portal Administrative Site. In considering geologic hazards, it was assumed that the impacts would be consistently local.

Intensity. The intensity of the impact considers whether the impact would be negligible, minor, moderate, or major. Negligible impacts were effects considered not detectable and that would have no discernible effect on public safety or soil resources. Minor impacts were those that would be present but would not be expected to have an overall effect on those conditions. Moderate impacts would be clearly detectable, and could have an appreciable effect on public safety and soil resources. Major impacts would have a substantial, highly noticeable influence on public safety and soil resources.

There will always be a potential for adverse impacts to life and property due to geologic hazards in Yosemite National Park. Therefore, management actions to avoid placement of facilities (or reduce numbers of people) in areas susceptible to geologic hazards may decrease the risks but would not necessarily reduce the intensity of the impact.

Duration. The duration of an impact considers whether the impact would occur in the short term or the long term. A short-term impact would be temporary in duration and would be associated with transitional types of impacts. A long-term impact would have a permanent effect on public safety and geologic conditions.

Type of Impact. Impacts were evaluated in terms of whether they would be beneficial or adverse to public safety and soil resources. Beneficial impacts would improve soil resources by restoring areas and limiting development. Adverse impacts would expose people and property to effects of earthquakes and rockfall events. Adverse impacts also would deplete or negatively alter soil resources.

Hydrology, Floodplains, and Water Quality

This section analyzed potential changes to hydrologic processes of the Merced River, including the river's interaction with its floodplain as well as water quality. This qualitative assessment focused on the physical and chemical processes of the Merced River that might be altered under the management practices called for as part of the proposed alternatives. Quantitative analyses of any potential changes to the Merced River were not feasible due to the programmatic nature of the plan. Analysis of the alternatives was qualitative and based on identified hydrologic processes, as described in the Hydrology, Floodplains, and Water Quality section in Chapter IV, Affected Environment.

Streamflow

The analysis examined potential changes to the free-flowing nature of the river as a result of the potential management actions listed under each of the action alternatives. This section addressed existing and potential future restrictions on streamflow and the possibility of removing current streamflow restrictions, such as dams or levees.

Floodplain

This section qualitatively analyzed the impacts or benefits to the river's floodplain due to potential changes in intensity and location of visitor use along the river. Due to the qualitative nature of this assessment, a reduction or modification of visitor use and facility development in the floodplain was perceived to be beneficial to the floodplain and protection of the river channel.

Water Quality

The analysis identified potential effects on water quality associated with visitor use and the generation of nonpoint-source pollution, such as refuse and automobile-related pollutants. Additionally, the analysis examined potential impacts on water quality from construction or removal of facilities within the river's floodplain.

Impact Assessment

Proposed management actions for each alternative were evaluated in terms of the context, intensity, and duration of the hydrologic impacts, and whether the impacts were considered to be beneficial or adverse to the hydrologic environment.

Context. The context of the impact considers whether the impact would be local or regional. For the purposes of this analysis, local impacts would be those that occur at localized areas due potential management actions within the corridor. Regional impacts would be impacts on the entire river corridor within Yosemite National Park.

Intensity. The intensity of the impact considers whether the impact would be negligible, minor, moderate, or major. Negligible impacts were effects considered not detectable and that would have no discernible effect on the hydrology or quality of the river. Minor impacts were effects on hydrologic processes that were slightly detectable but not expected to have an overall effect on the character of the river or its floodplain. Moderate impacts would be clearly detectable and could have an appreciable effect on hydrologic processes, the adjacent floodplain, or water quality. Major impacts would have a substantial, highly noticeable influence on the hydrologic environment and could permanently alter river processes, floodplain formation and evolution, and water quality.

Duration. The duration of the impact considers whether the impact would occur in the short term or the long term. A short-term impact would be temporary in duration and would be associated with transitional activities, such as facility construction or road removal. A long-term impact would have a permanent effect on the hydrologic environment, such as altering the dynamic processes that govern the free-flowing nature of the river, floodplain formation and evolution, or the condition of water quality.

Type of Impact. Impacts were evaluated in terms of whether they would be beneficial or adverse to the hydrologic environment. Beneficial impacts would sustain streamflow dynamics, allow natural processes to prevail, and protect or improve water quality. Adverse impacts would negatively alter hydrologic processes, thereby hindering natural processes and reducing protection of the river, its floodplain, and water quality.

Wetlands; Vegetation; Wildlife; and Rare, Threatened, and Endangered Species

National Park Service policy is to protect the natural abundance and diversity of all of the park's naturally occurring communities. To provide a consistent basis for analyzing impacts, and to ensure that alternatives are compared using the same frame of reference, the methodology described below was developed.

Some aspects of impact assessment methodology relate simply to whether an action breaches federal laws, regulations, and executive orders; similar state laws (for example, the California Endangered Species Act); or National Park Service Management Policies 2001 (NPS 2000f). A second level of impact assessment must address issues and concerns expressed during public scoping. The third, and probably the most important, level compares a projected impact with the natural history of a species or the known sensitivities of a habitat.

This assessment was based on the assumptions listed below.

·       The greater the size of a biotic community and the stronger its links to neighboring communities, the more valuable it is to the integrity and maintenance of biotic processes. Development limits the size of a community and fragments and disassociates communities from each other.

·       The more developed areas become, the less valuable they are as wildlife habitat. New development would increase human presence and increase the potential for soil, wildlife, and vegetation disturbance. The potential for negative wildlife interactions (such as human injury from wildlife and the introduction of unnatural food sources) also would increase. The removal of development from an area would increase the value of the habitat. However, in some cases, dispersal of the same number of visitors may well have a greater impact than an existing "containment" of disturbance within a designated area.

·       The effects of human food on the behavior, distribution, and abundance of wildlife species would continue in existing developments and would begin in new developments unless adequate facilities, education, and enforcement were provided.

·       The juxtaposition of natural communities to roads and other developments hinders the use of prescribed fire for restoring historic fire intensity, frequency, and severity.

·       Development and activities near sensitive habitats may adversely affect adjacent natural communities. Modifications of a river channel may cause channel instability and shifting, increased bank erosion, and changes in flood-flow elevations. The presence of well-vegetated banks and a sufficient width of riverbank protects the integrity of the river channel and shore.

·       Disturbance in or near a river and its tributaries may reduce the productive capabilities of associated natural communities. Modifications to river form, soil compaction, loss of riparian vegetation, removal of woody debris, and accelerated erosion and sediment transport influence important habitat characteristics such as riffle/pool complexes, substrate type, location, and cover. These physical aspects often determine the composition of vegetative and aquatic communities.

·       Roads change water inflow and outflow patterns and may dewater sections of meadow. The lack of a sufficiently high water table in meadows allows invasive plants to outcompete native vegetation and encourages conifer establishment, which threatens meadow communities.

·       Roads generally form barriers for wildlife and fragment habitat.

·       Development and impacts in riparian zones may influence critical water quality elements such as water temperature, suspended sediments, and nutrients. These elements interact in complex ways in aquatic systems and directly and indirectly influence patterns of growth, reproduction, and migration of aquatic organisms.

·       Ecological restoration of native communities would involve some short-term adverse impacts (e.g., smoke from prescribed burning) but over time can successfully replicate natural processes.

Quantitative analysis--that is, determining a measure of impact such as decibels of sound reaching the nest of a spotted owl--was not feasible for this methodology because this plan is programmatic and does not look at the implementation of specific actions. Qualitative analysis relies substantially on professional judgment, supported by extrapolation of relevant research, where appropriate, to reach reasonable conclusions as to the context, intensity, duration, and type of potential effect. When possible, mitigation measure(s) were incorporated into the document to reduce the adverse effects of impacts to natural resources.

Impact Assessment

The starting point for impact assessment is the natural processes of the Merced River corridor, including size, physical foundation, and components of the natural communities and ecosystems.

Proposed management actions under each alternative were evaluated in terms of the context, intensity, and duration of the impacts, as defined below, and whether the impacts were considered to be beneficial or adverse to the natural environment. Generally, the methodology for natural resource impact assessment follows direction provided in the Council of Environmental Quality Regulations for Implementing the National Environmental Policy Act, section 1508.27.

Context. Context suggests that certain impacts depend upon the setting of the proposed action. For instance, impacts that reduce the value of the Merced River in providing connectivity between habitat types could be minor if such connections are abundant in a given region, moderate or major if they are not. The context of the impact considers whether the impact would be local or regional.

Intensity. The intensity of the impact considers whether the impact would be negligible, minor, moderate, or major. These designations are used to describe both beneficial and adverse impacts. Negligible impacts were effects considered detectable but having no principal effect on biological resources. Minor impacts were effects that were detectable but not expected to have an overall effect on natural community structure. Moderate impacts would be clearly detectable and could have an appreciable effect on individual species, community ecology (e.g., the numbers of different kinds of amphibians present), or natural processes (e.g., fire). Major impacts would have a substantial, highly noticeable influence on natural resources. This would include impacts that have a substantial effect on individual species, community ecology, or natural processes.

Duration. Under this heading, both short- and long-term effects are relevant. A short-term impact would be temporary in duration and associated with transitional types of impacts, such as facility construction or bridge removal. Long-term impacts are somewhat more conjectural. For example, long-term declines in bird species diversity at heavily used sites may take decades to become evident.

Type of Impact. The type of impact considers whether the impact would be beneficial or adverse to biological resources. Effects to biological resources are considered beneficial if an action causes no detrimental effect and results in an increase in rare species or habitat components, native ecosystem processes, native species richness/diversity, or native habitat quantity and quality.

Air Quality

The air quality impact assessment involved the identification and qualitative description of the types of actions under the various alternatives that could affect air quality, corresponding emissions sources and pollutants, and relative source strengths. Based on the relative source strengths, a qualitative assessment was performed to determine the potential for higher pollutant emissions or concentrations, taking into account the frequency, magnitude, duration, location, and reversibility of the potential impact. In addition, regional pollutant transport issues were evaluated in the context of regional cumulative impacts.

Several assumptions were integrated into this assessment:

·       This plan would not affect the smoke management policies in the Fire Management Plan (NPS 2004b).

·       This plan would not affect the campfire regulations in the Valley.

·       The National Park Service would continue to ensure that all stationary emissions sources under its control or under the control of its concessioners comply with applicable air district rules and regulations.

·       The National Park Service would continue to participate in the regional air quality planning processes for ozone, PM-10/PM-2.5, and visibility impairment and would continue to review applications for new or modified major stationary sources upwind of the park, pursuant to Prevention of Significant Deterioration regulations.

·       The National Park Service would comply with U.S. Environmental Protection Agency's (U.S. EPA's) general conformity rule for any future actions that would occur within Madera County, which is part of San Joaquin Valley Air Basin, a nonattainment area for the national 1-hour ozone, 8-hour ozone, and PM-10 standards, and within Mariposa County, which is a nonattainment area for the national 8-hour ozone standard.

Quantitative analysis of potential air quality impacts was not feasible due to the programmatic nature of this plan. Rather, analysis of effects was qualitative, and professional judgment was applied to reach reasonable conclusions as to the context, intensity, and duration of potential impacts. When possible, mitigation measure(s) were incorporated into the plan to reduce the intensity of adverse effects.

Impact Assessment

The air quality impact assessment of the plan evaluated how types of changes would affect air pollutant emissions and concentrations. Air quality impacts were evaluated in terms of their context, intensity, and duration, and whether the impacts were considered to be beneficial or adverse.

Context. The context of the impact considers whether the impact would be local or regional. For the purposes of this analysis, local impacts would be those that occur within Yosemite National Park or impacts specific to the river corridor, including the El Portal Administrative Site. Regional impacts would be those related to the applicable air basins: Mountain Counties Air Basin and San Joaquin Valley Air Basin. With respect to air quality issues, both local and regional perspectives were relevant.

Intensity. The intensity of the impact considers whether the impact would be negligible, minor, moderate, or major. Negligible impacts were effects considered not detectable and that would have no discernible effect on air quality. Minor impacts were those that would be present but not expected to have an overall effect on those conditions. Moderate impacts would be clearly detectable and could have an appreciable effect. Major impacts would have a substantial, highly noticeable influence on local or regional air quality.

Duration. The duration of the impact considers whether the impact would occur in the short term or the long term. A short-term impact would be temporary in duration and would be associated with transitional types of impacts. A long-term impact would have a permanent effect on air quality.

Type of Impact. Impacts were evaluated in terms of whether they would be beneficial or adverse to air quality. Beneficial air quality impacts would reduce emissions or lower concentrations, and adverse impacts would have the opposite effect.

Noise

The noise impact assessment involved the identification and qualitative description of the types of actions proposed under each alternative that could affect the ambient noise environment, corresponding noise sources, relative source strengths, and other characteristics. Based on the relative source strengths, a qualitative assessment was performed to determine the potential for a substantial increase in ambient noise levels in areas where natural quiet is an important resource. Assessments were also performed where noise-sensitive uses are located or would expose persons to excessive noise levels taking into account the frequency, magnitude, duration, location, and reversibility of the potential impact. In addition, regional noise issues such as aircraft overflights were discussed in the context of long-term trends in wilderness noise exposure.

Quantitative analysis of potential noise impacts was not feasible due to the programmatic nature of this plan. Rather, analysis of effects was qualitative, with professional judgment applied to reach reasonable conclusions as to the context, intensity, and duration of potential impacts. When possible, mitigation measure(s) were incorporated into the plan to reduce the intensity of adverse effects.

Impact Assessment

The noise impact assessment evaluated how these three basic types of changes of the plan would affect the ambient noise environment in the corridor. Noise impacts were evaluated in terms of their context, intensity, and duration, and whether the impacts were considered to be beneficial or adverse.

Context. The context of the impact considers whether the impact would be local or regional. For the purposes of this analysis, local impacts would be those that occur within Yosemite National Park or impacts specific to the river corridor, including El Portal. In considering noise impacts, it was assumed that the impacts would be consistently local.

Intensity. The intensity of the impact considers whether the impact would be negligible, minor, moderate, or major. Negligible impacts were effects considered not detectable and that would have no discernible effect on the ambient noise environment. Minor impacts were those that would be slightly detectable but not expected to have an overall effect on those conditions. Moderate impacts would be clearly detectable and could have an appreciable effect. Major impacts would have a substantial, highly noticeable influence on the ambient noise environment.

Duration. The duration of the impact considers whether the impact would occur in the short term or the long term. A short-term impact would be temporary in duration and would be associated with transitional types of impacts, such as construction noise impacts. A long-term impact would have a permanent effect on the ambient noise environment related to park operations.

Type of Impact. Impacts were evaluated in terms of whether they would be beneficial or adverse to the ambient noise environment. Beneficial noise impacts would reduce associated levels and/or exposure, while adverse impacts would have the opposite effect.

Cultural Resources

Section 106 of the National Historic Preservation Act requires a federal agency to take into account the effects of its undertaking on properties included in, or eligible for inclusion in, the National Register of Historic Places (National Register) and provide the Advisory Council on Historic Preservation the reasonable opportunity to comment. This also applies to properties not formally determined eligible, but which are considered to meet eligibility requirements.

The methodology for assessing impacts to historic resources is based on the 1999 Programmatic Agreement (see Appendix H in the Merced River Plan/FEIS) (NPS 1999w). This includes: (1) identifying area of potential impact; (2) assessing the level of resource information available, and conducting appropriate research and evaluations necessary to obtain information about resources potentially eligible for listing in the National Register; (3) comparing the area of potential effect with that of resources listed, eligible, or potentially eligible for listing in the National Register; (4) identifying the extent and type of effect; (5) assessing these effects according to procedures established by the Advisory Council's regulations; and (6) considering ways to avoid, minimize, or mitigate adverse effects (36 CFR 800).

Cultural resource impact analysis in this environmental impact statement is described in terminology consistent with the regulations of the CEQ. CEQ regulations require that the impacts of alternatives and their component actions be disclosed. It is intended that the impact assessment will comply with the requirements of both NEPA and Section 106 of the National Historic Preservation Act. The determination of effect for the undertaking (implementation of the alternative) required by the 1999 Programmatic Agreement is included in the Conclusions section for each alternative. Consistent with CEQ regulations, the analysis of individual actions includes identification and characterization of potential impacts, including an evaluation of impact intensity. This is a fundamental difference between NEPA and the National Historic Preservation Act; the National Historic Preservation Act requires determinations of no effect or effect, and furthermore, where there is a determination of effect, requires a determination of whether that effect is adverse or not adverse. Effect is evaluated on the basis of whether an undertaking alters the characteristics of a property qualifying it for eligibility to the National Register. Intensity of impacts in the cultural resource analysis then, for purposes of NEPA, is defined as:

Negligible - Impact is barely perceptible and not measurable; confined to small areas or a single contributing element of a larger national register district or archeological site(s) with low data potential

Minor - Impact is perceptible and measurable; remains localized and confined to a single contributing element of a larger national register district or archeological site(s) with low to moderate data potential

Moderate - Impact is sufficient to cause a change in character-defining feature; generally involves a single or small group of contributing elements or archeological sites(s) with moderate to high data potential

Major - Impact results in substantial and highly noticeable change in character-defining features; involves a large group of contributing elements and/or individually significant property or archeological site(s) with high to exceptional data potential

Archeological resources are typically considered eligible for inclusion in the National Register because of the information they have or may be likely to yield. Intensity of impacts to archeological resources relates, additionally, to the importance of the information they contain and the extent of disturbance or degradation.

Traditional cultural resources are considered eligible for inclusion in the National Register as Traditional Cultural Properties when they are rooted in a community's history and are important in maintaining the continuing cultural identity of the community and meet National Register criteria for evaluation and integrity. Intensity of impacts to traditional cultural resources may relate to access and use of, as well as changes to, traditionally important places.

Historic sites, structures, and landscapes are considered eligible for inclusion in the National Register when they are associated with events that have made a significant contribution to the broad patterns of our history; when they are associated with the lives of persons significant in our past; or when they embody the distinctive characteristics of a type, period, or method of construction. Intensity of impacts to historic sites, structures and landscapes may relate to the extent of degradation of site and structural integrity, including the loss of landscape characteristics.

Council of Environmental Quality regulations, moreover, call for a discussion of the "appropriateness" of mitigation and NPS-12, the National Environmental Policy Act Guideline of the National Park Service, requires an analysis of the "effect" of mitigation. The "resultant" reduction in intensity from mitigation is an estimate of the effectiveness of mitigation under NEPA. It does not suggest that the level of effect as comprehended by Section 106 is similarly reduced.

Mitigation for NEPA purposes in this environmental impact statement is based on the park's 1999 Programmatic Agreement and includes avoidance of adverse effects or application of one or more Standard Mitigation Measures described in Stipulation VIII(A) of this Agreement. Avoidance strategies may include application of the Secretary of the Interior's Standards, design methods such as vegetation screening when placing new facilities in a historic district, and development of design standards to ensure compatibility.

In the case of archeological resources, mitigation includes avoidance of sites through design by minimizing effects through recovery of information that makes sites eligible for inclusion in the National Register. Generally, this data recovery will be based on the 1999 Archeological Synthesis and Research Design. In accordance with Stipulation VIII of the 1999 Programmatic Agreement, Standard Mitigation Measures may be implemented when avoidance is not feasible or prudent and the undertaking may result in an adverse effect on historic properties. Standard Mitigation Measures include documentation according to standards of the Historic American Buildings Survey/Historic American Engineering Record as defined in the October 1, 1997, Re-Engineering Proposal. The level of this documentation, which includes photography and a narrative history, would depend on significance (national, state, local) and individual attributes (individual elements of a cultural landscape, individually significant structures, etc.). When demolition of a historic structure is proposed, a select few architectural elements and objects may be salvaged for reuse in rehabilitating similar structures or added to the park's museum collection. However, only a limited number of elements and objects can be added to the museum. In addition, the story of history of alteration of the human environment, and reasons for that alteration, will be interpreted to park visitors.

According to Stipulation VII(C) of the 1999 Programmatic Agreement, effects on archeological resources are considered "not adverse" for purposes of Section 106 if data recovery is carried out in accordance with the 1999 research design. Under the revised regulations of the Advisory Council on Historic Preservation of May 18, 1999 (36 CFR 800, Protection of Historic Properties, Final Rule and Notice), data recovery is considered to be an "adverse effect." However, according to Part 800.3(A)(2) of those revised regulations, provisions of programmatic agreements in existence at the effective date of the new regulations are governed by the regulations in place when the Agreement was developed.

The National Park Service would continue to consult with culturally associated American Indian tribes according to stipulations of the Programmatic Agreement and specific agreements, such as the October 17, 1999, Agreement Between the National Park Service, Yosemite National Park, and the American Indian Council of Mariposa County, Inc. for Conducting Traditional Activities, to develop appropriate mitigating strategies for effects to traditional cultural resources. Such strategies could include identification of and assistance in providing access to alternative resource gathering areas, continuing to provide access to traditional use or spiritual areas, and screening new development from traditional use areas.

Visitor Experience

This impacts analysis evaluated four separate aspects of visitor experience: recreation, orientation and interpretation, visitor services, and wilderness experience. Separate methodologies have been developed for each of these impact areas. This analysis evaluated the quality characteristics of the visitor experience in terms of how they might be altered as a result of the various user capacity measures and management zone actions described in the alternatives.

Visitor experience in Yosemite National Park encompasses a broad spectrum of elements, including access to and availability of recreational opportunities, orientation and interpretation programs, various visitor services, and access to the Yosemite Wilderness. In addition, every individual visitor to Yosemite brings unique expectations and thus each has a unique experience. This Revised Merced River Plan/SEIS identifies, where possible, how the quality of the experience would change given application of potential management actions discussed in each of the action alternatives.

Developing a quantitative analysis of potential effects on visitor experience is not feasible because of the programmatic nature of this plan. Analysis of effects is therefore qualitative, and professional judgment was applied to reach reasonable conclusions as to the context, intensity, and duration of potential impacts.

Recreation

Assumptions for the recreation analysis are based on visitor studies conducted over the last several years (Manning et al. 1999a, b; ORCA 2000). The assumptions that framed the analysis included the following:

·       Under all alternatives, visitor demand would increase in all areas between 1999 and 2020.

·       The visitor preference for use of private vehicles to access the park would not change.

·       Lodging and camping facilities damaged and removed as a result of the January 1997 flood would not be replaced in the same place they were previously located.

·       Under the No Action Alternative, there would be no change in access to the Yosemite wilderness areas and no change to the wilderness permit system.

·       Under the No Action Alternative, stock use would continue as currently managed.

·       A diverse range of recreational activities is desirable.

·       Most visitors to the Valley feel that traffic congestion and crowding reduce the quality of visitor experience.

The analysis was based on whether there was a complete loss of a recreational opportunity, a change in access to or availability of a recreational opportunity, or a change in the aggregate of recreational opportunities for the visitor. This analysis evaluated how potential management activities under the various alternatives would affect recreation opportunities available in all segments of the Merced Wild and Scenic River within Yosemite National Park. The range of recreational opportunities includes floating, swimming and wading, hiking, backpacking, camping, rock climbing, fishing, sightseeing, photography, nature study, bicycling, and stock use.

Orientation and Interpretation

The impact analysis was based on whether there would be a change in the availability of the existing range of interpretation programs and orientation/information sources and services throughout the park resulting from potential management actions for each alternative.

Visitor Services

The analysis identified how potential management actions under the various alternatives would affect visitor services provided by the National Park Service, and the park partners, including the primary park concessioner. The services analyzed include all campgrounds (i.e., Merced Lake Backpackers Campground, Moraine Dome Backpackers Campground, Little Yosemite Valley Backpackers Campground, Camp 4, North Pines Campground, and Upper and Lower Pines Campgrounds), lodging (i.e., Yosemite Lodge, the Merced Lake High Sierra Camp, Housekeeping Camp, The Ahwahnee, Curry Village, and the Wawona Hotel), and food service and retail outlets in the Valley and in Wawona.

Wilderness Experience

Impact analysis associated with wilderness experience was based on whether there would be a change in opportunities for solitude and primitive recreation for visitors in the wilderness, and/or a change in the ability of the visitor to access the Yosemite Wilderness.

Impact Assessment

The assessment of potential impacts focused on the context, intensity, and duration of impacts that would result from the proposed management actions described for each alternative, relative to the four aspects of visitor experience, and whether those impacts were considered to be beneficial or adverse to visitor experience. The assessment looked specifically at whether access to or availability of some aspect of visitor experience would be altered.

Context. The context of the impact considers whether the impact would be local or regional. For the purposes of this analysis, local impacts would be those that occur within Yosemite National Park or impacts specific to the river corridor, including the El Portal Administrative Site. Regional impacts would be impacts on the affected region, which is defined in Chapter IV, Affected Environment.

Intensity. The intensity of the impact considers whether the impact to visitor experience would be negligible, minor, moderate, or major. Negligible impacts were effects considered not detectable to the visitor and therefore expected to have no discernible effect. Minor impacts were effects that would be slightly detectable, though not expected to have an overall effect on the visitor experience. Moderate impacts would be clearly detectable to the visitor and could have an appreciable effect on the visitor experience. Major impacts would have a substantial, highly noticeable influence on the visitor experience and could permanently alter access to and availability of various aspects of the visitor experience.

Duration. The duration of the impact considers whether the impact would occur in the short term or the long term. A short-term impact would be temporary in duration or association with transition types of activities. It is not likely that there would be temporary visitor experience impacts associated with this plan. A long-term impact would have a permanent effect on the visitor experience, such as the permanent closure of a campground.

Type of Impact. Impacts were evaluated in terms of whether they would be beneficial or adverse to visitor experience. Beneficial impacts would allow greater access to or availability of a recreational opportunity, interpretation or orientation program, other visitor services, or to a wilderness experience. Adverse impacts would reduce access to or availability of these four aspects of visitor experience.

Social Resources

Land Use

For the purposes of an environmental analysis under NEPA and National Park Service guidelines on NEPA policies, land use within Yosemite National Park has the sole designation of public parklands. From the NEPA perspective, the public parklands land use designation includes the myriad of uses that may occur in a public park, including camping, hiking, parking, etc. Although the National Park Service is re-evaluating the management zoning in the El Portal segment of the Merced River corridor in the action alternatives, the management zones only designate management direction for particular areas within the park and do not change the basic land use of the park. This Revised Merced River Plan/SEIS addresses only the management of lands under National Park Service control within Yosemite National Park and the El Portal Administrative Site. The basic designation of land use for the park, as defined by NEPA, would not change as a result of implementing any alternative of this Revised Merced River Plan/SEIS.

The land use analysis assumes that National Park Service policy concerning the acquisition of private lands within or adjacent to the park would not change. Thus, there would be no difference in land use policies between the No Action Alternative and the action alternatives.

Impact Assessment

Proposed management actions under each alternative were evaluated in terms of the context, intensity, and duration of land use impacts, and whether the impacts were considered to be beneficial or adverse to existing land use patterns.

Context. The context of the impact considers whether the impact would be local or regional. For the purposes of this analysis, local impacts would be those that occur at specific locations within the park. Regional impacts would be related to regional land use patterns. For the purposes of this document, it was assumed that land use impacts would be consistently local.

Intensity. The intensity of the impact considers whether the impact would be negligible, minor, moderate, or major. Negligible impacts were effects considered not detectable and that would have no discernible effect on land use patterns or land use compatibility. Minor impacts were effects on land use patterns that would be slightly detectable but would not be expected to have an overall effect on those conditions. Moderate impacts would be clearly detectable and could have an appreciable effect on land use patterns or result in land use incompatibility. Major impacts would have a substantial, highly noticeable land use incompatibility or would result in substantial changes to land use patterns.

Duration. The duration of the impact considers whether the impact would occur in the short term or the long term. A short-term impact would be temporary in duration and would be associated with transitional types of activities. A long-term impact would have a permanent effect on land use patterns or land use compatibility.

Type of Impact. Impacts were evaluated in terms of whether they would be beneficial or adverse to land use patterns. Beneficial impacts would improve compatibility among land uses. Adverse impacts would negatively alter land use patterns or result in new land uses that would not be compatible.

Transportation

The focus of this impact assessment was on the effect of potential management actions on traffic volumes and associated traffic flow and safety conditions. It was assumed that current alternative transportation services (regional public transit, shuttle buses, or Valley floor tours, etc.) would remain essentially unchanged under this plan. Given the programmatic nature of this plan, it was assumed that the plan would not result in any substantial, quantifiable construction activity. It was also assumed that the park would continue to implement restricted access to Yosemite Valley during peak season periods when criteria for implementation were met.

Quantitative analysis of potential effects was not feasible for this impact assessment due to the programmatic nature of the plan. Rather, analysis of effects was qualitative, and professional transportation engineering judgment was applied to reach reasonable conclusions as to the context, intensity, and duration of potential impacts. When possible, mitigation measure(s) were incorporated into the plan to reduce the intensity of adverse effects.

Traffic Flow Conditions

This section assessed potential changes in traffic volumes associated with changes to in-park visitor accommodations and/or parking facilities that could result from implementation of management action described for each alternative. Changes in traffic volumes were then judged as to whether they would substantially change the levels of congestion on the roadway system serving Yosemite National Park.

Traffic Safety/Conflicts

This section assessed potential changes in parking facilities (location and number of parking spaces) that could result from implementation of management actions for each alternative. Possible changes in parking availability (e.g., parking supply could be reduced, with resulting unmet parking demand being accommodated by visitors parking their vehicles at roadside locations) were then judged, in the context of prevailing traffic volumes, as to whether increased roadside parking would substantially affect the potential for traffic conflicts.

Impact Assessment

Proposed management actions for each alternative were evaluated in terms of the context, intensity, and duration of the transportation impacts, and whether the impacts were considered to be beneficial or adverse to traffic flow or traffic safety conditions.

Context. The context of the impact considers whether the impact would be local or regional. For the purposes of this analysis, local impacts would be those that occur within Yosemite National Park or specific to the river corridor, including the El Portal Administrative Site. Regional impacts would be impacts on regional highways providing access to the park.

Intensity. The intensity of the impact considers whether the impact would be negligible, minor, moderate, or major. Negligible impacts were effects considered not detectable and that would have no discernible effect on traffic flow or traffic safety conditions. Minor impacts were effects on traffic flow or traffic safety conditions that would be slightly detectable but would not be expected to have an overall effect on those conditions. Moderate impacts would be clearly detectable and could have an appreciable effect on traffic flow or traffic safety conditions. Major impacts would have a substantial, highly noticeable influence on traffic flow or traffic safety conditions and could permanently alter those conditions.

Duration. The duration of the impact considers whether the impact would occur in the short term or the long term. A short-term impact would be temporary in duration and would be associated with transitional types of activities. A long-term impact would have a permanent effect on traffic flow and/or traffic safety conditions.

Type of Impact. Impacts were evaluated in terms of whether they would be beneficial or adverse to traffic flow or traffic safety conditions. Beneficial impacts would improve traffic flow and traffic safety by reducing levels of congestion and occurrences of vehicle/vehicle, vehicle/bicycle, and vehicle/pedestrian conflicts. Adverse impacts would negatively alter traffic flow and traffic safety by increasing levels of congestion and occurrences of such conflicts.

Scenic Resources

The scenic resources analysis assumes that any management action taken under each alternative would conform with the National Park Service 1916 Organic Act. For the purposes of this analysis, management actions for each alternative would be assumed to have an impact (negative or beneficial) on scenic resources if they:

·       Introduce into or remove from the visual landscape any human-built structure or infrastructure, as it is viewed from within the Merced River corridor

·       Substantially change the quality of the visual landscape, whether foreground, intermediate ground, or background

·       Affect perceived viewer sensitivity, which is a function of the extent to which viewer activity is dependent on visual quality. This would include the viewer's experience in seeing any single viewpoint and in moving through a sequence of viewpoints, such as would be experienced in hiking along the river

The scenic resources analysis is confined to an examination of the physical effects on viewsheds and on physical attributes of landscape features that define important views. The ability of a visitor to enjoy a particular visual landscape or sequence of landscapes also is affected by the quality of the air between the viewer and the landscape. The effect of air quality on visual resources, specifically visibility, is examined in the air quality section.

Impact Assessment

The overriding management purpose of any national park, as defined by the National Park Service 1916 Organic Act, is to conserve the scenery and natural and historic objects. Following this direction, the National Park Service determines impacts on scenic resources by examining the potential effects of each alternative on both the physical component (any change to the landscape character and/or features) and with respect to how that change is experienced (any change in visibility, viewpoints, etc.).

Impacts of the various alternatives and the associated management actions on visual resources are examined and determined by:

·       Comparing the existing visual character of the landscape, characterized in terms of the color, textural scale, and formal attributes of landscape components and features, and the degree to which potential management actions under each alternative would affect (i.e., contrast or conform with) that character

·       Analyzing changes in experiential factors, such as whether a given action would result in a visible change, the duration of any change in the visual character, the distance and viewing conditions under which the change would be visible, and the number of viewers that would be affected

Scenic resources impacts consist of a substantial change that would: (a) change existing landscape character, whether foreground, intermediate ground, or background, and be visible from viewpoints the National Park Service has established as important; (b) change access to historically important viewpoints, or a sequence of viewpoints; or (c) change the visibility of a viewpoint or a sequence of viewpoints.

Context. The context of the impact considers whether the impact would be local or regional. For the purposes of this analysis, local impacts are site-specific to the scenic resource. Therefore, it was assumed that all scenic resource impacts would be local.

Intensity. Impacts are classified as negligible, minor, moderate, or major. The intensity of the impact depends both on the extent of the physical effect and the duration of that effect. A negligible impact would be barely perceptible and confined to a limited viewpoint. A minor impact would result in little change in existing landscape character and minor and temporary effects on viewers. A moderate impact would be noticeable to the viewer from one or more scenic viewpoints. A major impact would cause a substantial change in landscape character, a permanent change in access to viewpoints or sequence of viewpoints, or a permanent and substantial effect on visibility of a viewpoint or sequence of viewpoints.

Duration. The duration of the impact considers whether the impact would occur in the short term (e.g., temporary) or the long term (e.g., permanent).

Type of Impact. Impacts were evaluated in terms of whether the impact would be beneficial or adverse to the scenic resource. Beneficial impacts would improve the scenic resource. Adverse impacts would degrade the scenic resource.

Socioeconomics

The impacts analysis evaluated four separate socioeconomic areas: the social environment, visitor populations, the regional economy, and the primary park concessioner. Separate methodologies have been developed for each of these impact areas.

It is assumed that park overnighters who are potentially displaced from lodging in the park under the action alternatives would instead stay in the gateway communities as local overnighters. It is further assumed that in the short-term, some displaced park overnighters who may wish to lodge overnight in the region (as local overnighters) may not be able to due to a lack of lodging capacity in the gateway region, particularly during the peak season. In the long term, however, it is assumed that the regional lodging market would respond to visitor demand, and those displaced park overnighters would become local overnighters.

Quantitative analysis of potential effects on socioeconomic conditions was not feasible due to the programmatic nature of the plan. Rather, analysis of effects was qualitative, and professional judgment was applied to reach reasonable conclusions as to the context, intensity, and duration of potential impacts. When possible, mitigation measures were incorporated into the plan to reduce the adverse effects of socioeconomic impacts.

Social Environment

This section analyzed potential changes to the social environments of the communities of Yosemite Valley, El Portal, and Wawona, including housing, employee commute, community amenities, and recreational opportunities associated with the potential management actions under each of the action alternatives.

Visitor Populations

The analysis identified potential changes in park visitor accommodations that could result from implementation of management actions under each alternative. This section described changes in the composition of Yosemite visitors (e.g., park overnighters, local overnighters, and day visitors) and qualitatively addressed potential changes in visitor spending.

Regional Economy

This section qualitatively analyzed the impacts of changes in visitor spending and shifts in employment associated with the potential limits on park accommodations and other facilities. Due to the qualitative nature of the analysis, these impacts were addressed in terms of the affected region as a whole, and not at the individual county level.

Concessioner

The analysis identified how potential management actions under each alternative would affect facilities operated by the primary park concessioner. The analysis assumed that these facilities could be removed or reduced, and analyzed the impact on concession revenues.

Impact Assessment

Proposed management actions under each alternative were evaluated in terms of the context, intensity, and duration of the socioeconomic impacts, and whether the impacts were considered to be beneficial or adverse to the socioeconomic environment.

Context. The context of the impact considers whether the impact would be local or regional. For the purposes of this analysis, local impacts would be those that occur within Yosemite National Park or specific to the river corridor, including El Portal. Regional impacts would be impacts on the affected region, which is defined in Chapter IV, Affected Environment.

Intensity. The intensity of the impact considers whether the impact would be negligible, minor, moderate, or major. Negligible impacts were effects considered not detectable and that would have no discernible effect on the socioeconomic environment. Minor impacts were effects on the socioeconomic environment that would be slightly detectable but would not be expected to have an overall effect. Moderate impacts would be clearly detectable and could have an appreciable effect. Major impacts would have a substantial, highly noticeable influence on the socioeconomic environment and could permanently alter the socioeconomic environment.

Duration. The duration of the impact considers whether the impact would occur in the short term or the long term. A short-term impact would be temporary in duration and would be associated with transitional types of activities. A long-term impact would have a permanent effect on the socioeconomic environment.

Type of Impact. Impacts were evaluated in terms of whether the impact would be beneficial or adverse to the socioeconomic environment. Beneficial socioeconomic impacts would improve the social or economic conditions in the park or in the affected region. Adverse socioeconomic impacts would negatively alter social or economic conditions in the park or in the affected region, or would affect low-income populations.

Park Operations and Facilities

Impacts associated with potential management actions taken under each alternative were determined by examining:

·       Direct changes to staffing requirements, and policies associated with park operations

·       Indirect effects of park operations staffing, such as effects on utility and roadway infrastructure, flooding, and provision of utilities, especially potable water and sewer services

·       Direct increases in energy use and conservation policies caused by changes in park operations staffing, or policies

Impact Assessment

Potential management actions for each alternative were evaluated in terms of the context, intensity, and duration of impacts to park operations and facilities, and whether the impacts were considered to be beneficial or adverse to park operations and facilities.

Context. The context of the impact considers whether the impact would be local or regional. For the purposes of this analysis, local impacts would be those that occur within Yosemite National Park or specific to the river corridor, including El Portal. Regional impacts would be impacts that occur throughout the Sierra Nevada region. For the purposes of this analysis, it was assumed that all impacts would be local.

Intensity. The intensity of the impact considers whether the impact would be negligible, minor, moderate, or major. Negligible impacts were effects considered not detectable and that would have no discernible effect on park operations and facilities. Minor impacts were effects on park operations and facilities that would be slightly detectable but would not be expected to have an overall effect on the ability of the park to provide services and facilities. Moderate impacts would be clearly detectable and could have an appreciable effect on park operations and facilities. Major impacts would have a substantial, highly noticeable influence on park operations and facilities and include those impacts that would reduce the park's ability to provide adequate services and facilities to visitors and staff.

Duration. The duration of the impact considers whether the impact would occur in the short term or the long term. A short-term impact would be temporary in duration and would be associated with transitional types of activities. A long-term impact would have a permanent effect on park operations and facilities.

Type of Impact. Impacts were evaluated in terms of whether they would be beneficial or adverse to park operations and facilities. Beneficial impacts would improve park operations and/or park facilities. Adverse impacts would negatively affect park operations and/or facilities and could impede the park's ability to provide adequate services and facilities to visitors and staff.

Alternative 1: No Action

Natural Resources

Geology, Geohazards, and Soils

Analysis

Under Alternative 1, park would implement existing user capacity program, including the elements of the Merced River Plan (boundaries, classifications, Outstandingly Remarkable Values [ORVs], management zoning prescriptions, and River Protection Overlay), legal mandates, the General Management Plan, and other park policy documents. Geologic processes/conditions ORVs include the mature, meandering nature of the Merced River through Yosemite Valley, a classic V-shaped river through the gorge, evidence of ice-age glaciation (U-shaped and hanging valleys), extraordinary granite features (e.g., exfoliation domes), and the transition from igneous to metasedimentary rocks in the El Portal area. The following discussion provides an overview of the types of geologic impacts that could occur within the Merced River corridor under Alternative 1 in 2020 compared with existing conditions.

Rockfall Hazards. Rockfalls can be expected throughout Yosemite National Park in any area that has steep rock cliffs. Under Alternative 1, mass movement from unstable rock slopes would continue to result in rockfalls, debris flow, and rock avalanches, exposing visitors to potential injury and facilities to damage. Along the Merced River, rockfalls can occur in the upper wilderness reaches, along the edges of Yosemite Valley, within the gorge, and along the South Fork where the river is contained within canyons. Most rockfalls are associated with triggering events such as earthquakes, climatic changes such as rainfall events, or gradual stress release and exfoliation of the granite. Incidents of injury to visitors and damage to facilities from rockfall hazards are most likely to occur in the developed valley and canyon areas of the Merced River and South Fork corridor, such as in Yosemite Valley, the Merced River gorge along the El Portal Road, El Portal Administrative Site, and possibly in Wawona. The risk of rockfalls to visitors and facilities is considered low in the less-traveled and undeveloped wilderness areas, although rockfalls do occur throughout the park. Facilities located within proximity of the talus zone or within the rockfall shadow zone are most susceptible to damage from rockfalls. Rockfall frequency in the talus zone can be yearly to every several decades; risks posed by rockfalls include casualties and structural damage. Avoiding all rockfall-related risk is not possible, especially in narrow, steep valleys or canyons. The configuration of the Yosemite Valley walls and relatively narrow canyons suggest there are no "safe" areas within areas susceptible to rockfall risks (USGS 1998).

In the short term, management of user capacity in the river corridor under Alternative 1 would have no impact related to rockfall hazards. Current park management policies and the Yosemite Valley Geologic Hazard Guidelines (Appendix C in NPS 2000e), which require most new facilities and uses to be placed outside the talus zone and the rockfall shadow zone, would continue to be implemented, and levels of visitation would be similar to existing levels. Therefore, there would be no discernible increase in exposure of visitors or facilities to rockfall hazard. In the long term, however, visitation levels under Alternative 1 could reasonably be expected to increase until facility or utility capacities were reached. Such an increase would result in an increase in the number of park users exposed to rockfall hazards. Long-term impacts associated with an increase in the number of visitors exposed to rockfall hazards would be local, negligible to minor depending on future visitation levels), and adverse.

Seismic Hazards. Yosemite National Park is susceptible to earthquake ground shaking generated in seismically active zones on the east and west margins of the Sierra Nevada. Historically, seismic events in the Sierra Nevada and Yosemite National Park have been relatively infrequent; however, when they do occur, the resultant ground shaking is capable of triggering rockfalls and producing ground accelerations that are higher than some older, less structurally stable buildings can tolerate. Typically, risks of injury to visitors and damage to facilities from seismic events would be relatively greater in the developed portions of Yosemite National Park, such as Yosemite Valley, El Portal, and Wawona, compared with less developed and more remote areas. Buildings and other facilities placed within saturated alluvial soil could also be susceptible to secondary hazards from seismic ground shaking, including liquefaction and seismically induced settlement. Earthquakes are unavoidable, and those in the Sierra Nevada region would continue to expose visitors to potential hazards from ground shaking.

In the short term, management of user capacity in the river corridor under Alternative 1 would have no impact related to seismic hazards. Current park management policies and the Yosemite Valley Geologic Hazard Guidelines would continue to be implemented, and levels of visitation would be similar to existing levels. Therefore, there would be no discernible increase in exposure of visitors or facilities to seismic hazards. In the long term, however, visitation levels under Alternative 1 could reasonably be expected to increase until facility or utility capacities were reached. Such an increase would result in an increase in the number of park visitors who would be exposed to the effects of seismic ground shaking in the event of an earthquake. Long-term impacts associated with an increase in the number of visitors exposed to seismic hazards would be negligible to minor (depending on future visitation levels), and adverse.

Impacts to Soils. Management zoning prescriptions, implementation of the River Protection Overlay, protection of certain biological ORVs, implementation of the trailhead quota system, and other management tools implemented or available under Alternative 1 would continue to protect soils from excessive disturbance, erosion, or compaction along most of the 81-mile river corridor. However, visitor use in certain areas of Yosemite National Park can adversely affect soils by contributing to erosion, soil compaction, and removal of surface soils. Compaction of native soils can result from concentrated visitor use in localized areas or excessive vehicular traffic in unpaved areas. Excessive surface water runoff or loss of protective vegetation cover can cause erosion. Under management zoning for Alternative 1, specific segments of the Merced River, especially those zoned Developed (3A-3C), would continue to be subjected to such concentrated visitor use, resulting in continued erosion and compaction in these areas. Visitor use in the upper wilderness reaches and undeveloped areas adjacent to the main stem and South Fork of the Merced River would continue to be less concentrated and limited by the existing trailhead quota system, management zoning, and other applicable park management plans and guidelines; therefore, concentrated visitor use would not intensify impacts to soil resources in these areas. In addition, under Alternative 1, areas within and adjacent to the river corridor that have been restored and rehabilitated could be closed under the authority of the Superintendent's Compendium. Park management could also take certain actions under the user capacity program in response to data showing the need to protect resources (for example, closing a beach to commercial raft removal to protect the riverbank). Protection of certain biological ORVs within the River Protection Overlay, such as riverine and wetland habitat, also serve to protect soils in these areas. However, current use of well-developed and well-traveled areas within the park would continue to cause erosion and compaction. Continued river access would result in increased erosion, removal of vegetation, and decreased soil stability.

Under Alternative 1, existing management policies would continue to be implemented, and, in the short term, levels of visitation would be similar to existing levels. In the short term, current management of user capacity in the river corridor outside El Portal would have a negligible adverse impact due to the incremental effects of ongoing concentrated use with respect to soil erosion and compaction. In the long term, visitation levels under Alternative 1 would be expected to increase until facility or utility capacities were reached. However, no increases would occur within wilderness areas because the trailhead quota system would remain in effect. Such an increase would exacerbate the adverse effects of concentrated visitor use on park soils in certain areas zoned for relatively high use. Existing policies and programs to protect park resources and values under Alternative 1 would moderate the effects of future increases in park visitation in these areas and thus would reduce the extent of the adverse impact on park soils. Long-term impacts on park soils associated with an increase in the number of visitors by 2020 would be negligible to minor (depending on actual future visitation levels), and adverse.

The boundary for the El Portal segment of the river in Alternative 1 is defined by the 100-year floodplain or the River Protection Overlay, whichever is greater. Land within the boundary is zoned for Park Operations and Administration (3C) within developed areas and Day Use (2C). Under this alternative, future development could occur outside the river boundary within the El Portal Administrative Site, consistent with the legislative intent for the site. Temporary construction-related erosion could occur during periods of rain, while soil is exposed, and prior to the site restoration and cleanup phases of future projects. Erosion and soil loss typically occur immediately after initial site grading or following construction or a fill slope with exposed soil. Mitigation measures common to all alternatives (listed in Appendix B) include preparation, prior to commencement of any construction activities, of a stormwater pollution prevention plan to control erosion and sedimentation, and implementation of and compliance with all operational requirements in the plan during construction. With implementation of a stormwater pollution prevention plan during construction, erosion and soil loss associated with grading and construction activities would result in a local, short-term, minor, adverse impact. Long-term soil degradation would be minimal due to erosion controls and the intermittent nature of the grading activities. Implementation of the mitigation measures would reduce adverse effects on soils at the El Portal Administrative Site to negligible to minor.

Summary of Alternative 1 Impacts. Considering the unpredictable and unavoidable nature of rockfalls and earthquakes in conjunction with an expected, albeit limited, increase in park visitation over the long term, there would be a local, long-term, negligible to minor, adverse impact on public safety from geohazards, including rockfall and seismic ground shaking. Considering the ongoing effects of more concentrated visitor use that would occur in some areas of the river corridor, there would be a local, short-term and long-term, negligible to minor, adverse impact on soil resources due to erosion, compaction, and soil removal. However, current park management policies would continue to enhance and protect the geologic processes/conditions ORVs within the individual river segments.

Cumulative Impacts

Cumulative impacts related to geohazards and soil resources are based on analysis of past, present, and reasonably foreseeable future actions, in combination with potential effects of this alternative. The projects identified below include only those projects that could affect geologic resources within the Merced River corridor or in the park vicinity.

Rockfalls would remain an unavoidable and unpredictable hazard within Yosemite Valley, the gorge, and other areas along the river corridor. Actions proposed in the Yosemite Valley Plan would remove and relocate facilities from the base of the talus zone, consistent with the Yosemite Valley Geologic Hazard Guidelines. For example, plans proposed under the Curry Village and East Yosemite Valley Campgrounds Improvements and Curry Village Employee Housing projects incorporate the placement of essential, special, and standard facilities outside the base of talus and rockfall shadow zones, as appropriate. Although rockfall hazards cannot be eliminated, the Yosemite Valley Plan would remove the most hazard-vulnerable facilities, thereby resulting in a regional, long-term, minor, beneficial impact.

Earthquakes are unavoidable and unpredictable and represent a potentially long-term, adverse impact to public health and safety. However, past, present, and reasonably foreseeable future actions would result in a local, long-term, minor, beneficial cumulative impact to public health and safety with respect to seismic hazards, due to the efforts of the National Park Service to apply current building codes and consider geologic and seismic hazards in planning and management activities. These efforts protect site facilities in areas that could be directly affected by ground failure.

Although certain past, present, and reasonably foreseeable future projects proposed within the park and vicinity would increase soil degradation during construction activities or due to increased development, many park projects, especially those included in the Yosemite Valley Plan, contain restoration elements to protect valuable soil resources. Full implementation of the Yosemite Valley Plan would restore approximately 177 acres of soils, of which approximately 136 acres would be high-value resource soils. Future ecological restoration projects include the Visitor Use and Floodplain Restoration Program, which involves the ecological restoration of six campgrounds, Housekeeping Camp, and The Ahwahnee tennis court. The current ecological restoration project at Cook's Meadow involved the removal of an abandoned roadway and will be complete upon the construction of a boardwalk to provide meadow access while allowing the free flow of water in the meadow and protecting vegetation and soils. Past restoration projects included the Merced River Ecological Restoration at Eagle Creek, which involved restoration of the eroded creek channel, revegetating the creek banks, and redirecting visitor traffic to minimize bank erosion. The Lower Yosemite Fall Project removes a parking lot and restores it to natural conditions. The Happy Isles Gauging Station Bridge Removal and Cascades Diversion Dam Removal projects restored to a substantial degree the free-flowing condition in these areas, thus helping to reduce riverbank erosion. However, some cumulative actions could result in short-term or long-term degradation of soil resources; such projects include construction of campgrounds, lodging, employee housing, roadway rehabilitation projects, and other facilities. Although these types of projects could have site-specific, short-term, adverse effects (e.g., potential short-term construction erosion and soil loss), a key objective of each of these projects is to reduce soil degradation and better manage natural resources.

Although rockfalls are unpredictable and unavoidable by nature, rockfall and earthquake hazards under Alternative 1 and the cumulative projects would result in a local, long-term, minor, beneficial impact to public safety in Yosemite National Park and the El Portal Administrative Site. These beneficial effects would be the result of efforts by park management to relocate critical facilities outside the talus slope and rockfall shadow zones, to avoid construction of new facilities in these hazard areas, and to conduct appropriate geotechnical studies prior to construction of facilities on soils susceptible to seismic ground shaking. Ongoing management programs would limit the increase in future visitation, thereby limiting the increase in the numbers of users exposed to geohazards under Alternative 1 and the cumulative projects. The overall cumulative actions in combination with Alternative 1 would result in a net regional, long-term, minor, beneficial impact on soil resources.

Impairment

Alternative 1 would have a local, short-term and long-term, negligible to minor, adverse impact on geologic resources and soils. Although soil resources are a key natural resource component within Yosemite National Park, the effect of this alternative on soils would occur in very localized areas and would not be considered severe. The extent and quality of soil resources throughout most of the Merced River corridor would remain high. Therefore, Alternative 1 would not impair geologic resources for future generations.

Hydrology, Floodplains, and Water Quality

Analysis

The following discussion provides an overview of the types of impacts to hydrology, floodplains, and water quality that could occur within each segment of the Merced River corridor under Alternative 1, the No Action Alternative. Under Alternative 1, user capacity within the river corridor would be managed as it has been in the past, as identified and described in the park's General Management Plan and other current park policy and guideline documents (see table III-1). When visitor demand exceeds infrastructure capacities or when resources are being adversely affected, the park implements proactive measures and, in certain circumstances, specific restrictions to provide adequate protection for visitors and affected resources.

Impacts in Wilderness. The hydrologic processes ORV in the Wilderness segment includes the river's free-flowing character and excellent water quality. The ORV description also notes the river gradient, natural conditions (e.g., glacial remnants, a logjam in Little Yosemite Valley), and numerous cascades. Of the qualities described for the ORV, most are relatively insensitive to user-related impacts, with the exception of water quality. Water quality in the Wilderness segments is considered to be excellent.

User capacity within Wilderness segments of the Merced River would be addressed through the continued implementation of the trailhead quota system and periodic monitoring of wilderness resource conditions. If it is determined through monitoring that some areas are experiencing degradation due to overuse, park management would take proactive measures to restore resources and help prevent further damage.

In wilderness areas zoned Untrailed (1A) and Trailed Travel (1B), no new structures such as utilities, bridges (other than minor footbridges), and commercial overnight facilities are to be constructed. As such, Alternative 1 would not affect the floodplain or its ability to accommodate flood flow. Furthermore, visitation to the Wilderness segments of the river corridor is seasonal in nature and is controlled through the park's existing trailhead quota system. Visitor use in wilderness areas would continue to be limited; therefore, the effects to water quality, floodplain values, and related hydrologic processes as a result of soil compaction in the floodplain and soil erosion in wilderness areas are expected to be negligible.

Under Alternative 1, areas of more concentrated use in areas zoned Heavy Use Trail (1C) and Designated Overnight (1D) during the summer, such as along trails leading to Little Yosemite Valley and the vicinity, Backpackers Campground, Moraine Dome, and Merced Lake High Sierra Camp, would continue to experience current use patterns. Thus, localized, long-term, negligible to minor, adverse impacts to the hydrologic processes ORV associated with a reduction in water quality (due to soil compaction in floodplain areas) and soil erosion (as a result of these use patterns) would continue in these areas.

The continued removal of up to 3,000 gallons per day of water from the Merced River to support functions at the Merced Lake High Sierra Camp during the summer when this camp is open to the public represents a very small amount of the daily flow volume of the river in this area. Therefore, this withdrawal represents a negligible impact to the river's hydrologic processes at or downstream of the point of withdrawal.

Overall, visitor use in Wilderness segments of the river is expected to continue to have long-term, negligible impacts on hydrology, water quality, and the hydrologic processes ORVs.

Impacts in Yosemite Valley. The hydrologic processes ORVs in Yosemite Valley include the river's meandering character, world-class waterfalls, an active flood regime, oxbows, unique wetlands, and fluvial processes. Under Alternative 1, impacts resulting from historic bridges and other existing obstructions would continue to impede the free-flowing condition of the Merced River and subsequently alter stream processes that define channel characteristics. These restrictions to natural fluvial processes adversely affect the ability of the river to naturally discharge and dissipate channel-forming flows or flood flow. Streamflow would continue to be altered, thereby affecting the free-flowing nature of the river between the Happy Isles area and Pohono Bridge.

Beginning in the late 1800s and continuing to the mid 1900s, the Merced River floodplain was altered by development in the river corridor, particularly in the east Valley. Structural and recreational development has resulted in impervious surfaces, creation of flow barriers, and loss of vegetative cover, thus altering floodplain characteristics and the interaction between the floodplain and periods of high river flow. Under Alternative 1, the 100-year flood regime and floodplain formation and evolution, which are ORVs of the river, would continue to be altered by past developments and existing structures that were constructed prior to the river's designation as Wild and Scenic.

Visitor use has affected parts of the floodplain by compacting soils, reducing vegetative cover, altering streambanks, and inducing erosion. The continued use of streambanks and floodplains by park visitors would continue, particularly in more concentrated areas of use such as east Yosemite Valley. However, efforts by park management in more recent years have implemented numerous restoration efforts and installed boardwalks in some area, which has helped to minimize impacts to these floodplain resources.

Roadways, structures, and visitor-use areas would continue to be present in the floodplain and would be subject to flood hazards under this alternative. Executive Order 11988 on floodplain management and the Floodplain Management Guidelines (NPS 1993b) provide guidance for the protection of natural floodplain values and of life and property in the National Park System. For future structures, the National Park Service must avoid construction of facilities in a floodplain if alternative locations are available. Where no alternatives exist, policies allow construction of structures, such as day-visitor parking lots, picnic areas, and campgrounds, if risks to human life and property are studied and then minimized or mitigated through design. Other facilities such as medical facilities, schools, and fuel storage facilities are to be located outside the 500-year floodplain. Therefore, under Alternative 1, existing flood hazards could remain, whereas future flood hazards would be precluded or mitigated for any new facility construction in the floodplain.

During the warmer summer months when visitor use increases, water temperatures are higher, and the streamflow is lower than at other times of the year. Water quality at times can be adversely affected through the introduction of refuse and human-associated pollutants from visitors using the river and from high visitor use along streambanks and adjacent floodplain areas, particularly during summer weekends and holidays when visitor use peaks.

Roads, parking lots, and other impervious surfaces in or near the corridor can also release nonpoint-source pollutants into stormwater runoff that would subsequently be discharged to the river. These surfaces also accumulate refuse and other pollutants discarded by park visitors that could also degrade water quality in the Valley.

Current management zoning prescriptions, coupled with the more restrictive River Protection Overlay and other existing park management policies provide restrictions on visitor use that help control certain activities in the river corridor. Restorative elements of the program allow degraded streambanks and floodplain areas to recover. As a result, the hydrologic processes, floodplain values, and water quality in the Yosemite Valley are not expected to degrade below current levels.

Impacts in the Gorge. The hydrologic processes ORV for the Gorge segment is characterized by an exceptionally steep river gradient. The river in the Gorge is, in most places, difficult for visitors to safely access and has limited or no floodplain areas. These features are insensitive to visitor uses, and Alternative 1 would have no impact on this ORV.

Facilities and visitor use in the majority of the Gorge segment are minimal due to the topography and limited access. In addition, the river's steep gradient makes use of the river by visitors dangerous, even in periods of lower river flow. However, water quality and the hydrologic processes would continue to be adversely but negligibly affected by existing facilities, adjacent roads, turnouts, stormwater runoff, and riprap. These adverse impacts are expected to be slightly greater in the summer, when river flows are lower and visitor use is higher. Impacts to floodplains, water quality, and hydrologic processes in these areas would continue to be localized and long-term but negligible.

Impacts in El Portal. The hydrologic processes ORV for El Portal are related to the seasonally continuous rapids in that segment. This ORV is not readily affected by the river corridor boundary, the management zoning, or visitor use.

In El Portal, a bulk storage facility for petroleum fuels and a gas station would continue operation, as would transportation of fuels along Highway 140 adjacent to the river. The risk of a fuel release would remain, but would be mitigated by compliance with standard regulatory requirements for the transportation and storage of such materials and normal park operations and maintenance procedures. A release of fuel would constitute a short-term, adverse impact to water quality.

The river corridor boundary for the El Portal segment is drawn at the River Protection Overlay or the 100-year floodplain, which ever is greater. The current management zoning includes Park Operations and Administration (3C) (56 acres) and Day Use (2C) (137 acres). This boundary and zoning plan allows additional development or redevelopment within the areas zoned 3C. This could result in a loss of vegetation, soil compaction, and/or paving, with a potential for increased erosion and increased runoff from developed areas, and local, long-term, minor, adverse effects on hydrology and water quality. In addition, some development could occur within the floodplain, resulting in a local, long-term, minor, adverse effect on floodplain values.

Impacts in Wawona. The impoundment near Wawona has excellent water quality, which is a hydrologic processes ORV. The Wawona segments do not represent a hydrologic processes ORV, but the Below Wawona segment includes the free-flowing condition of the river and continual whitewater cascades which are ORVs. The ORVs for the below Wawona segment are not readily affected by visitor use and these features would continue to be protected under Alternative 1.

Until the historic Wawona Bridge (also called South Fork Bridge) and the temporary bridge are removed and replaced with a bridge designed to not impede the river flow (construction on a new bridge is scheduled to occur in 2005), these structures will continue to restrict the free-flowing conditions of the river and subsequently alter stream processes that define down-river channel characteristics. This will result in localized, minor to moderate, long-term, adverse effects to the hydrologic processes ORV at this location along the South Fork. Existing park management policies and elements of the existing Merced River Plan help ensure that the hydrologic processes ORVs are being protected and enhanced on a segment-by-segment basis for the Merced River corridor.

Summary of Alternative 1 Impacts. Hydrologic processes, floodplain values, and water quality are not expected to degrade below current levels; therefore, potential impacts of Alternative 1 to the hydrologic processes ORV in the river corridor are expected to be negligible.

Cumulative Impacts

Cumulative effects on hydrology, floodplains, and water quality are based on an analysis of past, present, and reasonably foreseeable actions in the vicinity of the Merced Wild and Scenic River corridor in combination with potential effects of this alternative.

Past Actions. The Merced River has been historically affected by a variety of projects that have introduced obstructions along its banks or into the river corridor; these obstructions have restricted river flow, modified the floodplain, and in some cases adversely affected water quality. The recent removal of the Happy Isles Gauging Station Bridge in east Yosemite Valley and the Cascades Diversion Dam in the Merced River gorge have substantially improved the free-flowing condition of the river and represent a cumulative, long-term, beneficial impact to the hydrologic processes ORV in these areas. However, the free-flowing condition of the Merced River has been adversely altered by the placement of fill and riprap to widen and stabilize segments A, B, and C of the El Portal Road in the gorge.

Present Actions. Utility infrastructure in east Yosemite Valley (primarily water and sewer lines) that is located in sensitive areas within the river corridor will be removed or abandoned in place; these utilities will be consolidated and realigned beneath roadways in many areas. In addition, numerous sewer lines that are currently exposed will be removed from the bed and banks of the river, reducing the potential for accidental discharges of sewerage to the river. This project will provide a cumulative, long-term, beneficial impact to the hydrologic processes ORV in the Valley.

The replacement of the South Fork Bridge near Wawona and the removal of the temporary bridge will remove abutments and piers from the bed and banks of the river. The new bridge has been designed to not impede the free-flowing condition of the South Fork and represents a cumulative long-term, beneficial impact to the hydrologic processes ORV Wawona.

Reasonably Foreseeable Future Projects. The Yosemite Valley Plan calls for numerous projects to be implemented within the river corridor Yosemite Valley, including the following:

·       Curry Village and East Yosemite Valley Campgrounds Improvements

·       Yosemite Lodge Area Redevelopment

·       Yosemite Village Interim Parking Improvements

·       Visitor Use and Floodplain Restoration Program Project

·       El Portal Old Wastewater Treatment Facility Removal

Although these projects could have site-specific, minor, short-term, adverse effects (e.g., construction-related effects on water quality), the general goal of these projects is to increase coordinated resource management, restore sensitive ecosystems, and remove, redesign, and/or improve existing infrastructure. In addition to those projects listed above, reconstruction of Segment D of El Portal Road could cause similar types of short-term, construction-related impacts as occurred during the construction of segments A, B, and C (e.g., effects on water quality). However, adverse impacts associated with Segment D reconstruction could be partially mitigated through project design (the design of Segment D would need to protect and enhance the ORVs of the Merced River in this area) and implementation of Best Management Practices, compliance monitoring, and restoration activities. Each of the above reasonably foreseeable future projects will be designed and constructed compliant with Wild and Scenic Rivers Act requirements related to user capacity elements, river boundaries, management zoning prescriptions and ORV protection and enhancement as defined in the final Merced Wild and Scenic River Comprehensive Management Plan.

Therefore, these reasonably foreseeable future actions, in combination with Alternative 1, could have a net long-term, local, minor, beneficial effect to the hydrologic processes ORVs of the Merced River corridor.

Impairment

Impacts to hydrology, floodplains, and water quality associated with Alternative 1, as well as the hydrologic processes identified for the various segments of the river corridor, are expected to be negligible to minor. Therefore, Alternative 1 would not impair the hydrologic resources of the park for future generations.

Wetlands

Analysis

The following discussion provides an overview of the types of impacts to wetland resources that could occur within each segment of the Merced River corridor under Alternative 1.

Biological ORVs common to the entire Merced River (main stem and South Fork) include riverine habitats, such as riparian forests, meadows, and the aquatic environment. Under Alternative 1, park use would, in the short term, continue consistent with existing conditions. Implementation of the management elements adopted in the Merced River Plan would provide protection and a management framework for river-related wetland resources. However, without the benefit of the VERP program, the expected long-term increases in park use outside the wild segments of the river could result in adverse impacts to wetland resources. Wetlands in localized areas (i.e., near facilities or other high-use areas) would continue to be negatively affected by existing development and human and stock use. In general, existing development (most of which is historic, such a road systems) would continue to adversely affect wetlands. Future development allowed under Alternative 1 would also have a limited potential for adverse effects on wetlands, although such effects would be minimized by compliance with existing policies, guidelines, and restrictions pertaining to wetland protection (see Chapter III). Development in wetlands could fragment habitat and impose unnatural barriers to plant and wildlife movements, thereby adversely affecting seed sources, nutrients, and plant dispersal and distribution patterns. Other types of adverse effects associated with human and stock use include local degradation of water quality (e.g., through the introduction of refuse, fecal coliform bacteria, and other human- and stock-associated pollutants), and potential introduction or spread of noxious weeds. Grazing, trampling, and soil compaction and erosion can result in the loss of soil structure, vegetation diversity, and plant productivity. These continued actions would have long-term, local, adverse effects on wetlands in the vicinity of facilities and areas of concentrated use. The degree to which wetlands would be affected depends on their proximity to facilities and high-use areas, as well as their sensitivity to perturbation. Thus, wetland resources could be positively affected by localizing facility- and use-related impacts away from more sensitive areas. Under Alternative 1, current park management tools, including the Merced River Plan management zoning and a variety of wetlands policies and guidelines, provide mechanisms for such actions.

Impacts in Wilderness. Wetland and aquatic habitats of the upper Merced River and the Wilderness segments of the South Fork are generally intact. However, some adverse effects on wetlands resources have occurred in areas where visitor use is intense (e.g., in the vicinity of the Little Yosemite Valley Backpackers Campground, Moraine Dome Backpackers Campground, Merced Lake High Sierra Camp and Backpackers Campground, and along major trail routes).

The biological ORVs of the Wilderness segments of the Merced River include high riparian species diversity, wetlands themselves, riparian areas that are intact and largely undisturbed by humans, and a nearly full range of riverine environments typical to the Sierra Nevada. Management zoning in the upper main stem of the Merced River and the South Fork above Wawona reflects existing management practices and use levels based on the Wilderness Act along with federal and Yosemite National Park wilderness policies and guidelines. Existing wilderness trailhead quotas limit user capacity for wilderness areas of the park. Wilderness zoning severely limits the type of new facilities (thus serving to limit user capacity) that could be built under the No Action Alternative. For example, large campsites with facilities are prohibited in zone 1B. Although future actions such as trail rehabilitation could occur under the current zoning, any proposed actions would be subject to the consistent set of criteria and considerations (including the Section 7 determination process) mandated by the Wild and Scenic Rivers Act, which would guide how the actions could be implemented. While impacts in high use areas would continue, most wilderness areas would remain relatively untouched. Under Alternative 1, wilderness user capacity limits would not change, and the current wilderness monitoring system would remain in place. Therefore, implementation of Alternative 1 is expected to result in only local, long-term, negligible, adverse effects on wetland resources in Wilderness segments. On a segment-wide basis, wetland resources throughout the wilderness segment would be protected and enhanced.

Impacts in Yosemite Valley. The size, structure, productivity, and continuity of wetland habitats (within wetlands and between wetland and riverine habitat) and aquatic habitats within Yosemite Valley have been affected over time by existing facilities and visitor use. Existing facilities such as roads, bridges, and ditches drain wet meadows, fragment the floodplain, and have adverse effects on wetland and aquatic habitats by imposing unnatural barriers to plant and wildlife movements, which in turn may accelerate both the drying of wetland habitats and conifer encroachment of wet meadow and riparian communities. These facilities were, for the most part, constructed many years prior to the Merced River's designation as Wild and Scenic. Existing roads, parking lots, and other impervious surfaces in or near the corridor are nonpoint sources of pollutants that discharge to low-lying wetlands as well as the aquatic habitat of the Merced River and its tributaries. Impervious surfaces accumulate automobile-related pollutants, refuse, and other nonspecific pollutants that are easily transported to adjacent or nearby wetland resources through stormwater runoff.

ORVs within Yosemite Valley include riverine habitats such as riparian forests, meadows, and the aquatic environment of the Merced River. Yosemite Valley is currently zoned to protect natural resources while providing a diverse visitor experience. Although large portions of the east Valley could remain developed under current zoning, the overall zoning (including the River Protection Overlay) of Yosemite Valley protects sensitive resources within the river corridor boundary (e.g., unique wetlands are zoned 2A, Open Space, which restricts activities and prohibits development of new roads and campgrounds). Valley zoning precludes several types of new development (e.g., new campsites are prohibited in the 2B, Discovery zone) where wetlands are located, while allowing such development in other zones. In addition, future actions (e.g., bridge removal, construction of new campsites) that could occur under the current zoning would be subject to the management elements adopted in the Merced River Plan, which guide how the actions could be implemented. The application of current zoning in combination with the other management elements adopted in the Merced River Plan would have short- and long-term, negligible, beneficial effects on wetlands and the biological ORVs in the Valley. However, the expected increase in park use under Alternative 1, combined with a lack of systematic monitoring, could result over time in local, long-term, minor, adverse effects on wetland resources and the biological ORVs in the Valley.

Impacts in the Gorge. Direct visitor intrusion into the majority of riparian areas of the Gorge segment has been and would continue to be minimal due to topography and inaccessibility. Biological ORVs of the Gorge segment include diverse riparian areas that are largely intact and relatively untouched by humans. The majority of the Gorge segment is zoned 2A, 2A+, and 2B, with less acreage zoned as 2C and 2D (the Cascades area). With the exception of the Cascades area, the majority of the gorge is relatively inaccessible, and visitor use in the gorge itself is unlikely to increase.

The riparian zone in the gorge would continue to be minimally affected by existing facilities, roads, turnouts, riprap, contaminated stormwater runoff, non-native species, and the use of nonmotorized watercraft (and associated visitor trampling at launch and removal locations). The riparian community throughout the Gorge, identified as a biological ORV, is indirectly and marginally affected by vehicle use on El Portal Road (and associated pollutants) and by non-native species. These continued effects on wetlands in the vicinity of facilities and areas of concentrated use would be long term, local, and adverse. The degree to which wetlands would be affected depends on their proximity to facilities and high-use areas, as well as their sensitivity to perturbation.

Gorge zoning under Alternative 1 precludes most types of new development (e.g., campgrounds and lodging, new roads) that have the potential to adversely affect wetlands. In addition, possible future actions that could occur under the current zoning would be subject to the consistent set of criteria and considerations adopted in the Merced River Plan as well as existing park management policies, which guide how the actions could be implemented. However, as described above, the expected increases in park use (resulting in higher traffic levels on El Portal Road and potentially higher levels of automobile-related pollutants in the area) under Alternative 1, combined with a lack of systematic resource monitoring could result in local, long-term, minor, adverse effects on wetland resources and the biological ORVs in the Gorge segment.

Impacts in El Portal. The biological ORVs of the El Portal segment include a diversity of riparian vegetation types. The total acreage included within the El Portal segment boundary under Alternative 1 would be 193 acres. This alternative would include primarily Park Operations and Administration (3C) zoning within existing developed areas and primarily Day Use (2C) zoning within undeveloped areas adjacent to the river. Of the 193 acres within the boundary, 137 acres would be zoned 2C and 56 acres (29% of the total acreage within the riparian corridor boundary) would be zoned 3C.

Examples of how the management elements of Alternative 1 would affect native wetlands and the biological ORVs of the El Portal segment are described below.

·       Portions of El Portal zoned 3C (e.g., the Trailer Village, Old El Portal) would allow redevelopment as well as additional development (e.g., employee residences in Yosemite Valley could be relocated to the El Portal Administrative Site). Potential development could have both short-term (e.g., construction-related) and long-term (e.g., fire suppression in the vicinity of structures), minor to moderate, adverse effects on wetlands and aquatic habitats. Although application of mitigation measures described in Appendix B would reduce impacts, long-term, minor to moderate, adverse effects to wetlands (e.g., conversion of wetland vegetation to developed facilities) would remain.

·       Areas of El Portal zoned 2C, including all areas within the River Protection Overlay and the Merced River 100-year floodplain, would allow only day uses and would restrict future development to supporting facilities such as roads, parking areas, trails, and utilities. Impacts resulting from the construction of such facilities would generally be localized. Any such development would be governed by existing mandates and guidelines pertaining to the protection of wetland resources (see Appendix A). Therefore, future development in zone 2C areas could have local, minor, adverse effects on wetland resources.

The zoning in El Portal could have short- and long-term, adverse effects on wetlands as the result of future actions that could be implemented under the proposed zoning (e.g., new park administration facilities, road repair). These impacts could be reduced through the application of mitigation measures described in Appendix B. The criteria and considerations (as well as other park policies and federal laws) would protect the biological ORVs. However, the increase in administrative use of the El Portal segment that could occur under Alternative 1, combined with a lack of systematic monitoring, could result in local, long-term, minor to moderate, adverse effects on wetland resources and the biological ORVs in parts of the El Portal segment.

Impacts in Wawona. Wetland and aquatic habitats within Wawona have been affected by historic facilities and visitor use. The size, structure, and productivity of wetland habitat as well as the continuity within wetlands and between wetlands and riverine habitat have decreased due to conifer encroachment, visitor trampling, spread of non-native species, continued use of existing development, and loss of natural drainage patterns due to roads and diversions. These effects are generally restricted to the limited areas of high visitor use within the Wawona segments and in the short term, these conditions would remain relatively constant.

In the long term, under Alternative 1, visitor use would continue to affect wetlands and aquatic habitat in high use areas by compacting soils, reducing vegetative cover, altering streambanks, and inducing erosion. Roads, parking lots, and other impervious surfaces in or near the corridor would continue to release nonpoint-source pollutants into stormwater runoff that could subsequently discharge to low-lying wetlands and the aquatic habitat of the South Fork.

Although the South Fork in Wawona has a variety of zones, ranging from 1B (Wilderness) to 3C (Park Operations and Administration), the base zones are low-intensity zones which mostly preclude new development, such as interpretive centers, food services, campgrounds and lodging, and day-visitor parking. The Wawona Golf Course and Wawona Picnic Area (2C), Wawona Campground (3A), Wawona Hotel (3B), and the Wawona maintenance facility (3C) allow a range of more intensive use levels consistent with existing development and uses. The zoning and continued use of these already developed sites is not expected to adversely affect local wetland resources.

Facilities within the River Protection Overlay, such as portions of the Wawona Campground and a portion of the Wawona maintenance facility would be inconsistent with the River Protection Overlay and could be removed or relocated. Local, short-term, negligible to minor, adverse effects to wetlands could occur if facilities were removed from the River Protection Overlay. These adverse impacts could be reduced to a negligible intensity by application of mitigation measures described in Appendix B. In the long term, facility removal could increase opportunities for natural revegetation and restoration of riparian habitat, resulting in a long-term, minor, beneficial impact on streamside (wetland) vegetation, a biological ORV for the Wawona segments.

Overall, the increase in park use under Alternative 1 combined with a lack of systematic monitoring could result in local, long-term, minor, adverse effects on wetland resources and the biological ORVs in the Wawona segment.

Summary of Alternative 1 Impacts. Compliance with existing park policies would help ensure that the biological ORVs related to wetlands are protected and enhanced. Under Alternative 1, continued application of limits on facilities development (through management zoning, the River Protection Overlay, and other Merced River Plan management elements) would allow many natural areas to remain relatively intact with continued protection and would allow restoration and enhancement of degraded native habitats. However, the expected long-term increase in park use would increase the intensity of visitor-related impacts, which, for the most part, would be restricted to areas of high intensity use (i.e., the east Yosemite Valley and El Portal). This, combined with a lack of systematic VERP monitoring, could result in local, long-term, minor to moderate, adverse effects on wetland resources and the biological ORVs in some portions of the Merced River corridor.

Cumulative Impacts

Cumulative effects to wetlands are based on analysis of past, present, and reasonably foreseeable actions in the Yosemite region in combination with potential effects of this alternative. The projects identified below include those projects that have the potential to affect local wetland patterns (i.e., within the river corridor) as well as wetlands parkwide.

Past Actions. Aquatic and riparian systems are the most altered and impaired habitats of the Sierra Nevada and are relatively rare in the context of the entire landscape. Wetlands in the Sierra Nevada have been drained since the earliest settlers attempted to "reclaim" meadows and other seasonally wet areas. Mountain meadows were commonly drained with the intent of improving forage conditions and to permit agriculture (Hughes 1934, as in NPS 1997b, UC Davis 1996). Development and activity in Yosemite National Park has reduced historic wet meadow acreage by 60 to 65%. Past and ongoing activities include recreational use, agriculture, and the construction of dams, diversion walls, bridges, roads, pipelines, riprap, buildings, campgrounds, and recreational features. Dams and diversions throughout most of the range have profoundly altered stream-flow patterns and water temperatures. Within the mountains, broad valleys with wide riparian areas were often reservoir sites, and much of the best former riparian habitat in the Sierra Nevada is now under water. The extent of the inundation across the range becomes apparent when one realizes that virtually all flatwater on the western slope of the Sierra Nevada below 5,000 feet is artificial (UC Davis 1996). These past actions have had long-term adverse effects on regional wetland and aquatic habitats.

In 1991, the U.S. Forest Service and the Bureau of Land Management developed a joint South Fork and Merced Wild and Scenic River Implementation Plan (NPS 1991b) for the segments of the main stem and South Fork of the Merced River that are under their jurisdiction. The plan is also a general management plan with many prescriptive goals and few actions. The plan endeavors to limit or end consumptive uses such as grazing within the river corridor and calls for the formalization of camping and launch facilities for nonmotorized watercraft. Implementation of these actions has a beneficial effect by eliminating impacts where feasible (grazing does not currently occur within the river corridor), concentrating impacts in areas able to withstand visitor use, and providing facilities that mitigate adverse effects associated with visitor use (e.g., restrooms).

A number of recently implemented projects have begun to reverse the centuries-long pattern of wetland degradation caused by localized human uses in the region. These include:

·       Merced River Ecological Restoration at Eagle Creek

·       Happy Isles Fen Habitat Restoration

·       Cascades Diversion Dam Removal

·       Happy Isles Gauging Station Bridge Removal

These projects have had local, long-term, moderate to major, beneficial effects on wetlands because they involve the restoration of previously degraded areas and thus enhance local and regional wetlands. In addition to these specific projects, one of the major goals of the Yosemite Valley Plan, adopted by the National Park Service in December 2000, is to restore, protect, and enhance the natural resources of Yosemite Valley. Actions set forth in the plan that result in beneficial effects on wetlands include the removal of roads, facilities, and services in the Valley (including roads through Stoneman Meadow and the southern portion of Ahwahnee Meadow, most parking areas in the east Valley, and commercial trail rides in the Valley), the relocation of employee housing out of the Valley, and the establishment of wetland restoration objectives.

Other past actions that have likely had a cumulative, beneficial effect on regional wetlands includes transportation-related projects, which have the general goals of increasing transportation options and reducing reliance on automobiles in the area. In addition, the update to the Fire Management Plan (NPS 2004b) seeks to improve ecosystem health and restore meadows and therefore would have a regional, long-term, moderate to major, beneficial effect on Yosemite's wetland resources throughout the Merced River corridor.

Present Actions. Present actions in the region have the potential to result in both beneficial and adverse effects on wetland resources:

·       The Cook's Meadow Ecological Restoration may help reverse the centuries-long pattern of wetland degradation due to localized human uses in the region.

·       Additional current projects with net long-term, minor to moderate, beneficial effects on wetland resources (resulting from revegetation and habitat restoration efforts, control of competing invasive species, and improved air or water quality) include the Happy Isles Dam Removal, Lower Yosemite Fall, Parkwide Invasive Plant Management Plan, Utilities Master Plan/East Yosemite Valley Utilities Improvement Plan, South Fork Bridge Replacement, and Yosemite Valley Shuttle Bus Procurement Plan.

·       Projects such as the Curry Village Employee Housing, Happy Isles to Vernal Fall Trail Reconstruction, the Yosemite Village Interim Parking Improvements, and Yosemite Motels Expansion could have short- and long-term, adverse effects on wetland resources through construction-related, operational, and maintenance actions.

Reasonably Foreseeable Future Actions. Reasonably foreseeable future actions proposed in the region are separated below into three general categories: (1) projects anticipated to have a net beneficial effect; (2) projects anticipated to have both beneficial and adverse effects; and (3) projects anticipated to have a net adverse effect.

Examples of projects that could have a cumulative, beneficial effect on regional wetlands include:

·       Wawona Campground Rehabilitation

·       Update to the Yosemite Wilderness Management Plan

·       Tuolumne Meadows Concept Plan

·       Tuolumne Wild and Scenic River Comprehensive Management Plan

·       Visitor Use and Floodplain Restoration Program

Although each of these projects may have slight local and short-term adverse effects (e.g., construction-related effects), the general goal of these projects is to increase coordinated resource management and to restore sensitive ecosystems. Therefore, these projects could have a long-term, beneficial cumulative impact to regional wetlands. For example, the update to the Yosemite Wilderness Management Plan could result in additional restrictions on wilderness facilities and activities, reducing site-specific erosion, trampling, and possibly stock use.

Reasonably foreseeable projects that could have mixed adverse and beneficial effects on regional wetlands include:

·       Curry Village and East Yosemite Valley Campgrounds Improvements

·       El Portal Concept Plan

·       Yosemite Lodge Area Redevelopment

Cumulative effects of these projects could be mixed, combining both adverse and beneficial effects. The net beneficial or adverse effects of these projects would be difficult to predict. For example, implementation of the El Portal Concept Plan could adversely affect wetland resources during construction (short-term effect) as well as permanently displace wetland resources in El Portal due to construction of new employee housing (long-term effect); however, removing employee housing and administrative facilities from Yosemite Valley (long-term, beneficial effect) would reduce these impacts as well as provide restoration opportunities. Adverse impacts associated with the El Portal Concept Plan could be mitigated to a lesser intensity through project design (the design would need to protect and enhance the ORVs of the Merced River), implementation of Best Management Practices, compliance monitoring, and restoration.

Reasonably foreseeable projects that could have local, adverse effects on wetlands include:

·       Environmental Education Campus Development Program

·       El Portal Road Improvements Project (Segment D)

·       Indian Cultural Center

·       Northside-Southside Drive Repaving

·       Out-of-Valley Campground Plan

·       Yosemite Village Interim Parking Improvements

Cumulative parkwide adverse effects would be primarily related to increased facilities and possible increases in visitor use and access. Each of the aforementioned projects has the potential to have local, minor to major, adverse effects on wetland resources during construction (short term) and through direct displacement of resources and effects of human use (long term). Examples of construction- and human-use-related effects on wetlands include direct displacement of vegetation, introduction of non-native species that invade into adjacent natural areas and displace native species, fragmentation of habitats that prevents genetic mixing, alteration of natural patterns, and increased erosion and sedimentation.

Past, present, and reasonably foreseeable future actions in the immediate vicinity of Yosemite National Park could have a long-term, minor, beneficial effect on wetlands and the biological ORVs within the Merced River corridor. Overall, these cumulative actions, in combination with Alternative 1, could have a net local, long-term, negligible, beneficial effect on parkwide wetlands and the biological ORVs of the Merced River corridor.

Impairment

Alternative 1 would have a local, long-term, minor to moderate, adverse effect on parkwide wetlands as well as the biological ORVs of the Merced River corridor and therefore would not impair wetland resources for future generations.

Vegetation

Analysis

The following discussion provides an overview of the types of impacts to vegetation resources that could occur within each segment of the Merced River corridor under the No Action Alternative.

Biological ORVs common to the entire Merced River (main stem and South Fork) include riverine habitats, such as riparian forests, meadows, the aquatic environment, and associated plant species. Under Alternative 1, park use would, in the short term, remain consistent with existing conditions. In general, adverse ongoing impacts to vegetation are confined to areas of high concentrations of use and near developed areas. Implementation of the management elements adopted in the Merced River Plan would provide protection and a management framework for river-related vegetation resources. However, without the benefit of the VERP program, the expected increase in use over time could result in new adverse impacts to vegetation resources. Adverse effects associated with human and stock use include local degradation of water quality (e.g., through the introduction of refuse, fecal coliform bacteria, and other human- and stock-associated pollutants), and potential introduction or spread of noxious weeds. Grazing, trampling, and soil compaction and erosion can result in the loss of soil structure, vegetation diversity, and plant productivity. The intensity of these adverse effects is expected to increase over time in conjunction with increases in park use except in the wilderness segments of the river, where Wilderness quotas will remain in place (day use of some more readily accessible wilderness trails could increase). The degree to which vegetation communities would be affected depends on their position relative to facilities and high-use areas, as well as their sensitivity to disturbance. Therefore, vegetation resources could be positively affected by localizing facility- and use-related impacts away from more sensitive areas. However, under Alternative 1, without implementation of the VERP program, effects on sensitive resources would not be systematically monitored. Therefore, park managers would not be receiving consistent and reliable data to inform management and planning decisions designed to protect, restore, and enhance sensitive vegetation resources that were being adversely affected by park use levels.

Impacts in Wilderness. Vegetation in the Wilderness segments of the Merced River is generally intact, except where visitor use is intense (e.g., in the vicinity of the Little Yosemite Valley Backpackers Campground, Moraine Dome Backpackers Campground, Merced Lake High Sierra Camp and Backpackers Campground, and along major trail routes). These facilities have existed for many years, long before the river's designation as Wild and Scenic.

High riparian species diversity in the Wilderness segments of the Merced River is a biological ORV. The upper main stem of the Merced River is zoned 1A, 1B, 1C, and 1D and the South Fork above and below Wawona is zoned 1A and 1B, reflecting management practices and use levels based on the Wilderness Act along with federal and Yosemite National Park wilderness policies and guidelines. The existing trailhead quota system limits user capacity for wilderness areas of the park. Wilderness zoning significantly limits the type of new facilities (thus serving to limit user capacity) that could be built under the No Action Alternative. For example, large campsites with facilities would be prohibited in zone 1B. In addition, the wilderness monitoring system would continue to provide data on the condition of vegetation in the wilderness segments. Although possible future actions (e.g., trail rehabilitation) could occur under current zoning, all proposed actions would be subject to the management elements adopted under the Merced River Plan and WIMS monitoring. On a segment-wide basis, the biological ORVs in the Wilderness segments of Yosemite National Park would be protected and enhanced.

Impacts in Yosemite Valley. Biological ORVs within the Yosemite Valley segment include riverine habitats such as riparian forests, meadows, and the aquatic environment of the Merced River. Yosemite Valley is zoned to protect natural resources while providing a diverse visitor experience (the Valley includes 1A, 1B, 2A, 2B, 2C, 3A, 3B, and 3C zoning). Large portions of the east Valley were developed prior to the river's designation as Wild and Scenic. Under the Merced River Plan, the overall zoning (including the River Protection Overlay) that now exists for Yosemite Valley protects sensitive resources within the river corridor boundary (e.g., unique wetlands are zoned 2A, Open Space, which restricts activities and prohibits development of new roads and campgrounds). Valley zoning precludes several types of new development (e.g., new campsites are precluded in the 2B, Discovery zone) that have the potential to adversely affect native vegetation, while allowing such development in other zones. In addition, possible future actions (e.g., bridge removal, construction of new campsites) that could occur under the current zoning would be subject to the management elements adopted in the Merced River Plan, which guide how the action could be implemented. However, future increases in park use under Alternative 1, combined with a lack of systematic monitoring or mechanisms by which to limit access or redirect visitor use in response to resource degradation, could result in local, long-term, minor to moderate, adverse effects on vegetation resources and the biological ORVs in the Valley.

Impacts in the Gorge. Biological ORVs in the Gorge segment include diverse riparian areas that are largely intact and relatively untouched by humans. The majority of the gorge is zoned 2A, 2A+, and 2B, with less acreage zoned as 2C and 2D (the Cascades area). With the exception of the Cascades area, the majority of the Gorge segment is relatively inaccessible, where visitor use is unlikely to increase over existing levels. Gorge zoning precludes most types of new development (e.g., campgrounds and lodging or new roads) that have the potential to adversely affect native vegetation. In addition, possible future actions that could occur under the current zoning would be subject to the management elements adopted in the Merced River Plan, as well as the management elements included in existing park management policies, which guide how the action could be implemented. However, the potential increase in use in parts of the Gorge segment under the No Action Alternative, combined with a lack of systematic monitoring or mechanisms by which to limit access or redirect visitor use in response to resource degradation, could result in local, long-term, minor, adverse effects on vegetation resources and the biological ORVs in the accessible portions of the Gorge segment.

Impacts in El Portal. Biological ORVs of the El Portal segment include a diversity of riparian vegetation types, as well as upland vegetation associations on the north-facing slopes of the river. The total acreage within the El Portal segment boundary under Alternative 1 would be 193 acres, which is equal to 17% of the total acreage included within the El Portal Administrative Site boundary. This alternative includes primarily Park Operations and Administration (3C) zoning within existing developed areas and primarily Day Use (2C) zoning within undeveloped areas adjacent to the river. Of the 193 acres within the riparian corridor boundary, 137 acres would be zoned 2C and 56 acres (29% of the total acreage within the riparian corridor boundary) would be zoned 3C.

Following are examples of how the management elements of Alternative 1 would affect native vegetation and vegetation-related biological ORVs in the El Portal segment. Those portions of El Portal zoned 3C (e.g., the Trailer Village, Old El Portal) would allow redevelopment as well as additional development (e.g., employee residences in Yosemite Valley could be relocated to the El Portal Administrative Site). Potential development could have both short-term (e.g., construction-related) and long-term (e.g., fire suppression in the vicinity of structures), minor to moderate, adverse effects on native vegetation. Although application of mitigation measures described in Appendix B would reduce impacts, long-term, minor to moderate, adverse effects to native vegetation (e.g., conversion of upland woodland or scrub vegetation to developed facilities) would remain in 3C areas.

The zoning in El Portal would allow additional development of park administration facilities as well as other actions such as road repair, which could have short- and long-term, adverse effects on native vegetation. The intensity of these impacts could be reduced through the application of mitigation measures described in Appendix B. Although the Merced River Plan management elements as well as other park policies and federal laws would protect biological ORVs, other vegetation resources (e.g., upland scrub or woodlands) could be adversely affected (long term, moderate). Overall, the increase in park administrative use allowed under Alternative 1, combined with a lack of VERP systematic monitoring, could result in local, long-term, minor to moderate, adverse effects on vegetation resources and the biological ORVs in portions of the El Portal segment.

Impacts in Wawona. The area in the immediate vicinity of Wawona has experienced past development prior to the Merced River's designation in 1987. Existing park infrastructure and facilities in this area include the Wawona Road, the Wawona Wastewater Treatment Plant and maintenance complex, an underground water and sewer utility corridor, employee housing, community amenities, campgrounds, the Pioneer Yosemite History Center and the Wawona Hotel and Golf Course.

Although the South Fork of the Merced River in Wawona has a variety of zones, ranging from 1B (Wilderness) to 3C (Park Operations and Administration), the base zones are 1B, 2A, and 2B. The 1B, 2A, and 2B zones preclude new development such as interpretive centers, food services, campgrounds and lodging, and day-visitor parking. The Wawona Golf Course and Picnic Area (2C), Wawona Campground (3A), Wawona Hotel (3B), and Wawona maintenance facility (3C) are zoned to allow a range of more intensive use levels consistent with existing development and uses. The zoning and continued use of these sites is not expected to adversely affect local vegetation resources in the short or long term.

Facilities within the River Protection Overlay, such as portions of Wawona Campground and a portion of the Wawona maintenance facility, would be inconsistent with the River Protection Overlay and could be removed or relocated. Local, short-term, negligible to minor, adverse effects to vegetation could occur during removal of any facilities from the River Protection Overlay. These adverse impacts could be reduced to a negligible intensity by applying mitigation measures described in Appendix B. Such removal or relocation of facilities could increase opportunities for natural revegetation and restoration of riparian habitat, resulting in a long-term, minor, beneficial impact on streamside vegetation, a biological ORV for the Wawona segments.

Overall, the increase in park use under Alternative 1, combined with a lack of systematic monitoring or mechanisms by which to limit access or redirect visitor use in response to resource degradation, could result in local, long-term, minor, adverse effects on vegetation resources and the biological ORVs in the Wawona segments.

Summary of Alternative 1 Impacts. Compliance with existing park policies would help ensure that the biological ORVs related to vegetation are protected and enhanced. Under Alternative 1, continued application of management zoning and the River Protection Overlay, in combination with the continued application of the management elements adopted in the Merced River Plan, would allow many natural areas to remain relatively intact and would direct restoration and enhancement of degraded native habitats. However, the estimated increase in park use over time would increase the intensity of visitor-related impacts for segments outside of Wilderness, where the existing quota system would continue to apply. This, combined with a lack of systematic monitoring or mechanisms by which to limit access or redirect visitor use in response to resource degradation, could result in local, long-term, minor to moderate, adverse effects on vegetation resources and the biological ORVs in some portions of the Merced River corridor.

Cumulative Impacts

Cumulative impacts to vegetation are based on analysis of past, present, and reasonably foreseeable actions in the Yosemite region in combination with potential effects of this alternative. The projects identified below include those projects that have the potential to affect local vegetation patterns (i.e., within the river corridor) as well as large-scale or regional vegetation patterns.

Past Actions. In general, vegetation patterns of the Sierra Nevada are relatively intact compared to other areas of California. Regional vegetation has been historically affected by logging, fire suppression, rangeland clearing, grazing, mining, draining, damming, diversions, and the introduction of non-native species. Portions of the Merced River and South Fork corridors within Yosemite National Park are relatively natural, especially in wilderness areas where use has had little effect on vegetation. Development and use of infrastructure within Yosemite Valley and throughout the Sierra Nevada have caused local, long-term, adverse alterations to native vegetation patterns since the early days of Euro-American occupation in the 19th century.

In 1991, the U.S. Forest Service and the Bureau of Land Management developed a joint South Fork and Merced Wild and Scenic River Implementation Plan (1991b) for the segments of the South Fork and main stem of the Merced River that are under their jurisdiction. The plan is also a general management plan with many prescriptive goals and few specific actions. The plan endeavors to limit or end consumptive uses such as grazing within the river corridor and calls for the formalization of camping and launch facilities for nonmotorized watercraft. Implementation of these actions has had a beneficial effect by eliminating impacts where feasible (grazing does not currently occur within the river corridor), concentrating impacts in areas able to withstand visitor use, and providing facilities that mitigate adverse effects associated with visitor use (e.g., restrooms).

A number of recently implemented projects have begun to reverse the centuries-long pattern of native vegetation degradation caused by localized human uses in the region. These include:

·       Merced River Ecological Restoration at Eagle Creek

·       Happy Isles Fen Habitat Restoration

These projects are all anticipated to have local, long-term, moderate to major, beneficial effects on native vegetation because they involve the restoration of previously degraded areas and thus enhance local and regional native plant diversity. In addition to these specific projects, one of the major goals of the Yosemite Valley Plan, adopted by the National Park Service in December 2000, is to restore, protect, and enhance the natural resources of Yosemite Valley. Actions set forth in the plan that result in beneficial effects on vegetation include the removal of roads, facilities, and services in the Valley, as well as the relocation of employee housing out of the Valley and the establishment of vegetation restoration objectives (expressed as acres per habitat type).

Other past projects that have likely had a beneficial, cumulative effect on regional vegetation include transportation-related projects, which have the general goals of increasing transportation options and reducing reliance on automobiles in the area. In addition, the Fire Management Plan seeks to improve ecosystem health and meadows and therefore would have a regional, long-term, moderate to major, beneficial effect on Yosemite's vegetation resources and the biological ORVs throughout the Merced River corridor.

Present Actions. Present actions occurring in the region have the potential to result in both beneficial and adverse effects on vegetation resources, including:

·       The Cook's Meadow Ecological Restoration is anticipated to have a local, long-term, moderate to major, beneficial effect on native vegetation because it involves the restoration of previously degraded areas and thus enhances local and regional native plant diversity.

·       Additional current projects with net long-term, minor to moderate, beneficial effects on vegetation resources include the Happy Isles Dam Removal, Lower Yosemite Fall Project, Parkwide Invasive Plant Management Plan, Utilities Master Plan/East Yosemite Valley Utilities Improvement Plan, and Yosemite Valley Shuttle Bus Procurement.

·       Projects such as the Curry Village Employee Housing, Happy Isles to Vernal Fall Trail Reconstruction, and the Yosemite Motels Expansion could have short- and long-term, adverse effects on vegetation resources through construction-related, operational, and maintenance actions.

·       The South Fork Bridge Replacement could have both adverse and beneficial effects on vegetation.

Reasonably Foreseeable Future Actions. Reasonably foreseeable future actions proposed in the region are separated below into three general categories: (1) projects anticipated to have a net beneficial effect; (2) projects anticipated to have both beneficial and adverse effects; and (3) projects anticipated to have a net adverse effect.

Examples of projects that could have a beneficial cumulative effect on regional vegetation include:

·       Red Peak Pass Trail Rehabilitation

·       Wawona Campground Rehabilitation

·       Update to the Yosemite Wilderness Management Plan

·       Visitor Use and Floodplain Restoration Program

·       El Portal Old Wastewater Treatment Facility Removal

Reasonably foreseeable future actions that could have mixed adverse and beneficial effects on regional vegetation include:

·       Tuolumne Meadows Concept Plan

·       Tuolumne Wild and Scenic River Comprehensive Management Plan

·       Curry Village and East Yosemite Valley Campgrounds Improvements

·       El Portal Concept Plan

·       Yosemite Lodge Area Redevelopment

Cumulative effects of these projects could be mixed, combining both adverse and beneficial effects. The net beneficial or adverse effects of these projects are difficult to predict. For example, implementation of the El Portal Concept Plan could adversely affect vegetation resources during construction (short term) and permanently displace vegetation resources in El Portal due to construction of new employee housing (long term); however, removing and relocating employee housing and administrative facilities from Yosemite Valley to El Portal (long-term, beneficial effect) would reduce the intensity of these impacts and provide restoration opportunities in the Valley. Adverse impacts associated with the El Portal Concept Plan could be mitigated to a lesser intensity through project design (the design would need to protect and enhance the ORVs of the Merced River), implementation of Best Management Practices, compliance monitoring, and restoration.

Reasonably foreseeable future actions that could have local, adverse effects on vegetation include:

·       El Portal Road Improvements Project (Segment D)

·       Environmental Education Campus Development Program

·       Indian Cultural Center

·       Northside-Southside Drive Repaving

·       Out-of-Valley Campground Plan

·       Yosemite Village Interim Parking Improvements

Cumulative parkwide adverse effects would be primarily related to increased facilities and possible increases in visitor use and access. Each of these projects could have local, minor to major, adverse effects on vegetation resources during construction (short term) and through direct displacement of resources and effects of human use (long term). Examples of construction- and human-use-related effects on vegetation patterns include direct displacement of vegetation, introduction of non-native species that invade into adjacent natural areas and displace native species, fragmentation of habitats that prevents genetic mixing, alteration of natural patterns, and increased erosion and sedimentation.

Past, present, and reasonably foreseeable future actions in the immediate vicinity of Yosemite National Park could have a long-term, minor, beneficial effect on vegetation and the biological ORVs within the Merced River corridor. Overall, these cumulative actions, in combination with Alternative 1, could have a net local, long-term, negligible, beneficial effect on parkwide vegetation and the biological ORVs of the Merced River corridor.

Impairment

Alternative 1 would have a local, long-term, minor to moderate, adverse effect on parkwide vegetation as well as the biological ORVs of the Merced River corridor and therefore would not impair vegetation resources for future generations.

Wildlife

Analysis

Impacts to wildlife in the park can generally be classified into three main categories (Knight and Cole 1991): (1) habitat modification and fragmentation by disturbing vegetation and soil and changing microclimates (e.g., trampling habitat); (2) changing foraging or feeding ecology (e.g., discarding food or deliberately feeding animals); and (3) disturbance, whether intentional (harassment) or unintentional (e.g., wildlife observation, hiking across an animal's territory). Biological ORVs common to the entire Merced River (main stem and South Fork) include riverine wildlife habitats, such as riparian forests, meadows, and the aquatic environment of the river.

The following discussion provides an overview of the types of impacts to wildlife resources that could occur within each segment of the Merced River corridor from application of management elements of the Merced River Plan (e.g., boundaries, classifications, ORVs, management zones, the River Protection Overlay, and the Section 7 determination process) and other user capacity programs. In the short term under Alternative 1, overall visitor numbers are expected to remain relatively similar to existing levels. In the long term, however, overall visitor numbers would likely increase with the projected increase in visitor demand, resulting in adverse effects to wildlife and the biological ORVs. Visitation increases would not affect the vast majority of the Wild segments of the river because the Wilderness Trailhead Quota System would remain in place.

Impacts in Wilderness. Wildlife habitats within the upper Merced River are generally intact. Meadows within the Wilderness segments of the Merced River occur at Merced and Washburn Lakes, Echo Valley, at isolated locations along the Merced River, and at small alpine lakes. Coniferous forest habitats along the upper Merced River are structurally diverse and support a full community of associated wildlife species, except in the vicinity of campsites or other visitor areas, which occur in a very small percentage of the river corridor. Wilderness segments of the South Fork include a nearly full range of riverine environments typical to the Sierra Nevada that are largely intact and undisturbed by humans. Biological ORVs of the Wilderness segments include riverine wildlife habitats such as riparian forests, meadows, and the aquatic environment of the river.

Under Alternative 1, continued implementation of the park's existing user capacity management program could have short-term, negligible, beneficial impacts on wildlife and the biological ORVs in wilderness areas of the upper Merced River by reducing visitor effects on these sensitive resources. For example, trailhead quotas limit overnight entries into wilderness areas of the park. Existing trailhead quotas based on resource protection goals also restrict the number of day users on both established trails and cross-country routes in wilderness areas to prevent degradation of high-elevation meadows and impacts to associated wildlife species. Visitor numbers are expected to increase, but trailhead quotas would ensure no increase in overnight wilderness use. However, Alternative 1 provides a means for monitoring adverse effects on wildlife resources and the biological ORVs through WIMS, which implements management actions (e.g., restoring campsites and trails, limiting wilderness permits, or closing trails) to reduce visitor-use impacts on these resources.

Under Alternative 1, wilderness areas would maintain wilderness zoning (1A, 1B, 1C, and 1D) and would continue to reflect current management practices, based on the Wilderness Act and federal and Yosemite National Park wilderness policies and guidelines. Management zoning and the River Protection Overlay severely limit the types of facilities that could be built or rebuilt (e.g., large campsites with facilities are prohibited in zone 1B). All future actions (e.g., trail rehabilitation) would be subject to the consistent set of criteria and considerations (including the Section 7 determination process) from the Merced River Plan, which would guide how the actions could be implemented. Therefore, the application of management zoning and other Merced River Plan elements would have a local, short- and long-term, negligible, beneficial effect on wildlife and the biological ORVs in the Wilderness segments.

Under Alternative 1, impacts to wildlife and the biological ORVs would be concentrated in the few wilderness areas of high visitor use (e.g., Little Yosemite Valley Backpackers Campground and along major trail routes). The majority of the Wilderness segments of the planning corridor are intact and not affected by visitor use.

In addition, Alternative 1 includes a monitoring system to provide feedback on resource conditions. Management actions to reduce trailhead use in areas where visitor use is adversely affecting wildlife resources and the biological ORVs. Overall, the use of management zoning and other Merced River Plan elements, together with the trailhead quota and monitoring system, would protect and enhance native wildlife and the biological ORVs in Wilderness segments.

Impacts in Yosemite Valley. Riparian areas and low-elevation meadows are the most productive communities in Yosemite Valley. The high quality and large extent of riparian, wetland, and other riverine areas provide rich habitat for river-related species, neotropical migrant songbirds, and bat species. These habitats and associated species are examples of biological ORVs in Yosemite Valley.

Under Alternative 1, the Merced River Plan's management zoning, River Protection Overlay and other elements would further the protection of native wildlife. The existing pattern of development in Yosemite Valley was established long before the river's designation as Wild and Scenic. Although portions of the east Valley would remain developed and subject to facility and visitor-use effects, the existing Restricted Access Plan would continue to be implemented when visitor levels exceed the capacity of the park transportation infrastructure. Park management could also close areas that show unacceptable impacts to allow for restoration of wildlife habitat or to reduce the intensity of the adverse effects. Current zoning and the River Protection Overlay preclude several types of new development (e.g., new campsites are not allowed in the Day Use zone at Cathedral Beach) that could otherwise adversely affect native wildlife. All future actions (e.g., bridge removal, construction of new campsites) would be subject to the Merced River Plan's set of criteria and considerations which require the protection of ORVs. The application of existing facility-based user capacity management tools, management zoning, and the Merced River Plan's criteria and considerations would have a local, long-term, minor, beneficial effect on native wildlife and the biological ORVs.

In the long term, visitor numbers are expected to increase, resulting in local, minor to moderate, adverse effects on wildlife resources (e.g., habitat disturbance due to trampling, erosion, and social trails; human disturbance to wildlife; and human/wildlife conflicts). This effect is expected to be minor in areas of lower visitor use such as the west Valley. However, this effect is expected to be moderate in areas of high day-visitor use such as the east Valley, and specifically the Yosemite Lodge area. Although Alternative 1 provides measures to reduce user capacity (e.g., restricting access to the east Valley and area closures), this alternative does not provide a systematic VERP program to assess the effects of visitor use on wildlife resources and the biological ORVs.

This alternative would not substantially affect wildlife resources in areas of the Valley with low visitor use. However, local, short- and long-term, adverse effects to native wildlife would continue to occur in areas of intense visitor use as a result of Alternative 1 and the lack of a VERP monitoring and management program to prevent increased visitor-use effects. Overall, Alternative 1 would result in a net local, long-term, minor to moderate, adverse effect.

Impacts in the Gorge. Montane hardwood conifer is the dominant habitat type adjacent to riparian areas below Yosemite Valley. This type is broadly transitional between upper-elevation forest types and chaparral and is thus the most important type for migratory wildlife and their associated predators. Biological ORVs of the Gorge segment include river-associated wildlife species and diverse riparian areas that are largely undisturbed by humans.

The majority of the Gorge segment is zoned 2A+, 2B, 2C, and 2D. With the exception of the Cascades area, the Gorge segment would continue to be relatively inaccessible and visitor use is unlikely to increase substantially. Gorge zoning precludes most types of new development (e.g., campgrounds and lodging, new roads) that have the potential to adversely affect wildlife. In addition, future actions that could occur under the current zoning would be subject to the Merced River Plan's consistent set of criteria and considerations which require the protection of ORVs, as well as existing park management policies, which guide how the actions could be implemented.

In the Cascades area and the few other accessible areas of the gorge segment, visitor numbers under Alternative 1 are expected to increase, resulting in moderate, adverse effects on wildlife in these areas. Increased use of El Portal Road by visitors traveling to the Valley could also affect wildlife in the Gorge segment through noise, traffic, and other human disturbance. Alternative 1 does not provide a systematic VERP program to assess the effects of visitor use on wildlife resources and the biological ORVs.

Overall, the application of zoning and the Merced River Plan's consistent set of criteria and considerations within the Gorge segment in combination with the lack of a monitoring program to prevent increased visitor-use effects would have a local, long-term, minor, adverse effect on native wildlife and the biological ORVs in accessible portions of the Gorge segment.

Impacts in El Portal. Montane hardwood conifer is the dominant habitat type adjacent to riparian areas below Yosemite Valley. This type is broadly transitional between upper-elevation forest types and chaparral and is thus the most important type for migratory wildlife and their associated predators. In El Portal, wildlife access among habitats has been affected for many decades on the north side of the river by roads, residences, lodging, and other human activities and development. In contrast, habitats on the south side of the river are relatively pristine and free of human-built barriers, although some historic mining operations occurred in this area. The quality of these north-facing habitats is recognized as an ORV in the El Portal area. El Portal has a base zone of 2C, with large tracts zoned 3C. The El Portal segment of the river corridor includes the 100-year floodplain or River Protection Overlay, whichever is greater, as adopted in the Merced River Plan.

Examples of how management zoning, the River Protection Overlay, and the criteria and considerations under the Merced River Plan would affect native wildlife and the biological ORVs of El Portal are described below.

·       The Sand Pit in El Portal was once used to mine sand from the Merced River. Under its 2C zoning, the Sand Pit could be restored, which would allow natural processes to prevail at this location, enhance the aquatic habitat, and allow natural revegetation with riparian species. Additional portions of the El Portal corridor are zoned 2C, preventing intensive development in areas adjacent to the river that support sensitive wildlife habitats. The 2C zoning of the Sand Pit and other 2C areas could result in a local, moderate, beneficial effect on the biologic ORV.

·       Portions of the El Portal corridor are zoned 3C (e.g., the Trailer Village, Old El Portal), which could allow additional development or redevelopment (e.g., employee residences in Yosemite Valley could be relocated to the El Portal Administrative Site). Potential development could have both short-term (e.g., construction-related) and long-term (e.g., night lighting, human presence, fire suppression in the vicinity of structures), minor to major, adverse effects on native wildlife. Although the application of mitigation measures described in Appendix B, would reduce impacts, long-term, minor to moderate, adverse effects on native wildlife (e.g., conversion of upland woodland or scrub vegetation to developed facilities) would remain in these areas.

The application of management zoning, the River Protection Overlay, and the criteria and considerations under the Merced River Plan would help to protect and enhance wildlife and the biological ORVs in the river corridor in El Portal. The zoning in El Portal allows for road repair as well as additional development of park administration facilities, which could have short- and long-term, adverse effects on native wildlife. The management elements and criteria and considerations (including the Section 7 determination process) would help protect the biological ORVs both within and outside the boundary.

In the long term, visitor numbers may increase in close proximity to the river, resulting in minor, adverse effects on wildlife resources in areas of moderate day-visitor use such as El Portal. Alternative 1 does not provide a systematic monitoring program with indicators of adverse user capacity effects on wildlife resources and the biological ORVs.

Although Alternative 1 includes the use of existing user capacity management tools, management zoning, and the criteria and considerations of the Merced River Plan, the existing narrow boundary and the lack of the VERP program would result in local, long-term, minor to moderate, adverse effects on native wildlife and the biological ORVs in the accessible and developed portions of El Portal segment.

Impacts in Wawona. Habitats along the South Fork--meadow, riparian, scrub and chaparral, and coniferous and deciduous forests--comprise nearly a full range of wildlife habitats that are intact and undisturbed by humans. The meadow and wetland communities of Wawona are currently designated as biological ORVs.

The Wawona segments include limited developed areas such as the Wawona Golf Course and Wawona Picnic Area (zoned 2C), Wawona Campground (zoned 3A), Wawona Hotel (zoned 3B), and the Wawona maintenance facility (zoned 3C). These areas were developed long before the river's designation as Wild and Scenic. Adverse effects to wildlife associated with developed areas include habitat fragmentation due to buildings, roads, and other development, vehicle and pedestrian noise, human presence, increased human/wildlife conflicts, and other visitor-use effects. These adverse effects are ongoing, local, and minor to moderate. However, the base zones within the South Fork in Wawona (1A, 2A, and 2B) preclude new development such as interpretive centers, food services, campgrounds and lodging, and day-visitor parking. Overall, this zoning results in a long-term, negligible, beneficial impact to wildlife and the biological ORVs.

Facilities within the River Protection Overlay, such as portions of Wawona Campground and a portion of the Wawona maintenance facility, are inconsistent with the River Protection Overlay and could be removed or relocated. Such removal or relocation of facilities could increase opportunities for natural revegetation and restoration of riparian habitat, resulting in a local, long-term, minor, beneficial impact on streamside vegetation, a biological ORV. Local, short-term, negligible to minor, adverse effects to wildlife could occur during any removal of facilities from the River Protection Overlay. These adverse impacts would be reduced to a negligible intensity by application of mitigation measures described in Appendix B. Limits on facilities through management zoning and the River Protection Overlay in combination with the Merced River Plan's criteria and considerations would allow existing natural areas to remain relatively intact and would direct restoration and enhancement of degraded native habitats.

In the long-term, visitor numbers are expected to increase, resulting in moderate, adverse effects on wildlife resources in the limited areas experiencing high visitor use in the Wawona segments. Alternative 1 does not provide a systematic VERP program to monitor the effects of visitor use on wildlife resources and the biological ORVs.

Overall, to the increase in park use under Alternative 1 and the lack of a VERP program to assess the effects of visitor-use would have a local, long-term, minor to moderate, adverse impact on native wildlife and the biological ORVs in those parts of the Wawona segments most used by visitors.

Summary of Alternative 1 Impacts. Compliance with existing park policies would help ensure that the biological ORVs related to wildlife are protected and enhanced. Under Alternative 1, management zoning and the River Protection Overlay would continue to preclude various types of new development that have the potential to affect native wildlife (a minor, beneficial impact). In the long term, the combination of existing facility-based user capacity management tools, management zoning, the River Protection Overlay, and application of a consistent set of decision-making criteria and considerations (including the Section 7 determination process) would have a negligible, beneficial effect on wildlife and the biological ORVs within the river corridor. These elements would preclude inappropriate development, encourage the removal of inappropriate facilities from the immediate river corridor, subject new actions to a rigorous planning process designed to eliminate adverse effects on the ORVs, and manage zones to their desired conditions. This would allow existing natural areas to remain relatively intact and would direct restoration and enhancement of degraded native habitats.

Local, short- and long-term, adverse effects on native wildlife could occur as the result of future actions that could be implemented under the proposed zoning (e.g., new campsites, parking facilities, road repair).

However, because Alternative 1 does not include a systematic monitoring program in non-Wilderness segments to prevent increased visitor-use effects on wildlife resources and the biological ORVs, this alternative could result in adverse effects on wildlife resources. Under Alternative 1, four basic adverse impacts would continue to occur and are expected to worsen over time in localized areas of moderate and high visitor use in the non-Wilderness segments of the corridor: degradation in habitat quality for riparian and wet-meadow-dependent wildlife; loss of habitat connectivity and increased habitat fragmentation; increased human-related disturbance; and continued stress on wildlife through factors such as the increasing presence of non-native species and disturbance-tolerant wildlife.

Overall, Alternative 1 would result in a local, long-term, minor to moderate, adverse impact on native wildlife and the biological ORVs within the river corridor.

Cumulative Impacts

Cumulative effects to wildlife are based on analysis of past, present, and reasonably foreseeable actions in the Yosemite region in combination with potential effects of this alternative. The impact intensity would depend on whether the effects are expected to interact cumulatively. The projects identified below include those projects that have the potential to affect local wildlife patterns (i.e., within the river corridor) as well as large-scale or regional wildlife patterns.

Past Actions. Wildlife communities have been manipulated almost since the establishment of the park. Regional wildlife has been historically affected by logging, fire suppression, rangeland clearing, grazing, mining, draining, damming, diversions, and the introduction of non-native species. Fur-bearing mammals were trapped by park rangers until 1925; lions were considered dangerous predators and controlled through the 1920s; bears were artificially fed as a tourist attraction until 1940. Natural wildfires, with their generally beneficial effects on wildlife habitat, were routinely suppressed until 1972 (Wuerthner 1994). Past and ongoing activities include recreational use as well as the construction of dams, diversion walls, bridges, roads, pipelines, riprap, buildings, campgrounds, and other recreational features.

Yosemite's largest mammal, the grizzly bear, was extirpated from the region and from the state in the 1920s. Other mammal species that survive but are extremely rare are the fisher, wolverine (possibly extinct), and Sierra Nevada red fox. Several bird species have probably been reduced in Yosemite Valley by human activity, but are present in less disturbed areas of the park. Willow flycatchers no longer nest in Yosemite Valley--probably due as much to parasitism by brown-headed cowbirds as to destruction of riparian and meadow habitat. On a wider scale, apparent population declines have been detected in numerous other bird species in the Sierra Nevada, including Yosemite National Park. Possible causes for these declines include grazing, logging, fire suppression, development, recreational use, pesticides, habitat destruction on wintering grounds, and large-scale climate changes.

Amphibians in Yosemite National Park have suffered population declines similar to those seen in the rest of the Sierra Nevada (Drost and Fellers 1996). Red-legged frogs likely were found in Yosemite Valley in the past but are now are presumed extirpated. Significant factors in their disappearance probably include a reduction in perennial ponds and wetlands, and predation by bullfrogs. At higher elevations, mountain yellow-legged frogs and Yosemite toads are still present in a number of areas, but are severely reduced in population and range. Foothill yellow-legged frogs have disappeared completely from the park, if not the entire Sierra Nevada. Research continues to identify the causes of amphibian declines in the Sierra Nevada; possible causes include habitat destruction, non-native fish, pesticides, and diseases. Most fish currently found in the Merced River and its tributaries in Yosemite National Park have been introduced. Prior to trout stocking for sport fishing, native fish in Yosemite were probably limited to the rainbow trout and the Sacramento sucker, both of which were present only in the lower portions of the Merced River (i.e., Yosemite Valley and below). Rainbow trout introduced through stocking from other waters and fish hatcheries have now hybridized with, and/or has displaced, the original strain.

In 1991, the U.S. Forest Service and the Bureau of Land Management developed a joint South Fork and Merced Wild and Scenic River Implementation Plan for the segments of the main stem and South Fork of the Merced River that are under their jurisdiction. The plan is also a general management plan with many prescriptive goals and few actions. The plan endeavors to limit or end consumptive uses such as grazing within the river corridor and calls for the formalization of camping and launch facilities for nonmotorized watercraft. Implementation of these actions has a beneficial effect by eliminating impacts where feasible (grazing does not currently occur within the river corridor), concentrating impacts in areas able to withstand visitor use, and providing facilities that mitigate adverse effects associated with visitor use (e.g., restrooms).

Recently implemented projects have begun to reverse the centuries-long pattern of native vegetation and wildlife habitat degradation due to localized human uses in the region. These include:

·       Merced River Ecological Restoration at Eagle Creek

·       Happy Isles Fen Habitat Restoration

·       Cascades Diversion Dam Removal

These projects are expected to have local, long-term, moderate to major, beneficial effects on wildlife habitat because they involve the restoration of previously degraded areas and thus enhance local and regional wildlife diversity. In addition to these specific projects, one of the major goals of the Yosemite Valley Plan is to restore, protect, and enhance the natural resources of Yosemite Valley. Actions set forth in the plan that result in beneficial effects on wildlife include the removal of roads, facilities, and services in the Valley (including roads through Stoneman Meadow and the southern portion of Ahwahnee Meadow, most parking areas in the east Valley, and commercial trail rides in the Valley), as well as the relocation of employee housing out of the Valley and the establishment of vegetation restoration objectives (expressed as acres per habitat type). Another broader plan, the Fire Management Plan, seeks to improve ecosystem health and restore meadows and therefore would have a regional, long-term, moderate to major, beneficial effect on Yosemite's wetland resources and the biological ORVs throughout the Merced River corridor.

Present Actions. Present actions in the region have the potential to result in both beneficial and adverse effects on wildlife resources:

·       Current projects with net long-term, beneficial effects on wildlife resources (resulting from revegetation and habitat restoration efforts, control of competing invasive species, and improved air quality) include the Cook's Meadow Ecological Restoration, Happy Isles Dam Removal, Lower Yosemite Fall Project, Parkwide Invasive Plant Management Plan, Utilities Master Plan/East Yosemite Valley Utilities Improvement Plan, and Yosemite Valley Shuttle Bus Procurement.

·       Projects such as the Curry Village Employee Housing, Happy Isles to Vernal Fall Trail Reconstruction, and Yosemite Motels Expansion could have short- and long-term, adverse effects on wildlife resources through construction-related, operational, and maintenance actions.

·       The South Fork Bridge Replacement could have mixed adverse and beneficial effects on wildlife resources.

Reasonably Foreseeable Future Actions. Reasonably foreseeable future actions proposed in the region are separated below into three general categories: (1) projects anticipated to have a net beneficial effect; (2) projects anticipated to have both beneficial and adverse effects; and (3) projects anticipated to have a net adverse effect.

Examples of projects that could have a cumulative, beneficial effect on wildlife resources include:

·       Wawona Campground Rehabilitation

·       Update to the Yosemite Wilderness Management Plan

·       Red Peak Pass Trail Rehabilitation

·       Visitor Use and Floodplain Restoration Program

Although each of these projects could have slight local, short-term, adverse effects (e.g., construction-related effects), the general goal of these projects is to increase coordinated resource management and to restore sensitive ecosystems. Therefore, these projects could have a long-term, beneficial cumulative impact to regional native wildlife. For example, the update to the Yosemite Wilderness Management Plan could result in additional restrictions on wilderness facilities and activities, reducing site-specific erosion and trampling and possibly stock use.

Reasonably foreseeable future actions that could have mixed adverse and beneficial effects on wildlife resources include:

·       Tuolumne Meadows Concept Plan

·       Tuolumne Wild and Scenic River Comprehensive Management Plan

·       Curry Village and East Yosemite Valley Campgrounds Improvements

·       El Portal Concept Plan

·       Yosemite Lodge Area Redevelopment

Cumulative effects of these projects could be mixed, combining both adverse and beneficial effects. The net beneficial or adverse effects of these projects are difficult to predict. For example, implementation of the Yosemite Lodge Area Redevelopment project has the potential to adversely affect wildlife resources during construction (short term), as well as permanently displace wildlife and remove wildlife habitat with the relocation of Northside Drive (long term); however, removing Yosemite Lodge facilities from the River Protection Overlay and floodplain would allow for revegetation and restoration of wildlife habitat within the Merced River corridor (long-term, beneficial effect). Adverse impacts associated with construction activities could be partially mitigated through project design and implementation of Best Management Practices, compliance monitoring, and restoration.

Reasonably foreseeable future actions that could have an adverse effect on wildlife resources include:

·       El Portal Road Improvements Project (Segment D)

·       Environmental Education Campus Development Program

·       Indian Cultural Center

·       Northside-Southside Drive Repaving

·       Out-of-Valley Campground Plan

·       Yosemite Village Interim Parking Improvements

Cumulative parkwide adverse effects would be related to increased facilities, access, and regional population growth. Each of these projects could have local, minor to major, adverse effects on wildlife resources during construction (short term) and due to direct displacement of resources (long term). Construction- and human-use-related effects on wildlife resources include those resulting from heavy equipment and construction/demolition activities (e.g., soil compaction, dust, vegetation removal, noise, and the introduction and spread of non-native species), night lighting, human presence, human/wildlife conflicts, fire suppression in the vicinity of structures. These actions could result in direct losses of nests or burrows, and indirect effects through the disturbance of nesting birds.

Past, present, and reasonably foreseeable future actions in the immediate vicinity of Yosemite National Park could have a long-term, minor, beneficial effect on wildlife and the biological ORVs within the Merced River corridor. Overall, these cumulative actions, in combination with Alternative 1, could have a net local, long-term, minor, adverse effect on parkwide native wildlife and the biological ORVs of the Merced River corridor.

Impairment

Alternative 1 would have a local, long-term, minor to moderate, adverse effect on parkwide native wildlife as well as the biological ORVs of the Merced River corridor and therefore has the potential to impair wildlife resources for future generations.

Rare, Threatened, and Endangered Species

Analysis

Due to the programmatic and prescriptive nature of the Merced River Plan, it is not possible to quantify discrete impacts to individual species. The conclusions herein provide programmatic information about rare, threatened, or endangered (sometimes referred to as "special-status") plants and animals.

Species present in low numbers or that are of limited distribution are the most sensitive to impacts. Species that are less rare but more vulnerable to the types of actions that might take place (as a result of management decisions under the Merced River Plan) serve as important measures of adverse impacts to park ecosystems. Species that are members of both groups are considered to be vulnerable at a programmatic level (i.e., as a result of even broad management decisions implicit in this Revised Merced River Plan) and are discussed below as examples of possible effects.

River-related rare, threatened, and endangered species are components of the biological ORV. Therefore, the magnitude of any adverse or beneficial effect to river-related special-status species has been evaluated for the corresponding effect on the biological ORV. The following discussion provides an overview of the types of impacts to special-status species that could occur within each segment of the Merced River corridor from application of Merced River Plan management elements (e.g., boundaries, classifications, ORVs, management zones, the River Protection Overlay, and the Section 7 determination process for the Merced River corridor) and existing user capacity measures. In the short term under Alternative 1, visitor numbers are expected to remain similar to existing levels. In the long term, however, visitor numbers would likely increase, resulting in adverse effects to special-status species and the biological ORVs.

Impacts in Wilderness. Habitats within the upper Merced River are generally intact, except in the few areas where visitor use is intense (e.g., in the vicinity of the Little Yosemite Valley Backpackers Campground, Moraine Dome Backpackers Campground, Merced Lake High Sierra Camp, and Backpackers Campground, and along major trail routes). All of these facilities pre-date the river's designation as Wild and Scenic. The Wilderness segment of the South Fork includes a nearly full range of riverine environments typical to the Sierra Nevada that are largely intact and undisturbed by humans. No facilities (other than a few trails) occur in the upper and lower portions of the South Fork, access is difficult, and visitor and stock use is low. Rare, threatened, and endangered species of plants and wildlife reported in the South Fork generally occur in wilderness portions of the corridor or in relatively inaccessible habitats. Biological ORVs of the Wilderness segments of the Merced River include riverine habitats such as riparian forests, meadows, and the aquatic environment of the river, and associated special-status species such as Yosemite toad and mountain yellow-legged frog.

The following examples describe general actions and related adverse effects of visitor use that would continue to occur in the vicinity of facilities and areas of concentrated use in the upper main stem of the Merced River. These effects are generally considered long term and adverse. In areas of the wilderness reaches of the South Fork of the Merced River, continued use of existing facilities (e.g., trails) at a similar level of intensity would not adversely affect rare, threatened, and endangered species.

·       Trampling, grazing, or camping within meadows could have direct effects on rare plants, such as the Mono Hot Springs evening primrose, and habitat for ground dwelling special-status wildlife species, including Sierra Nevada mountain beaver.

·       Trampling and grazing of meadows could reduce habitat for voles, therefore reducing the prey base for great gray owls.

·       Stock use would continue to support the local abundance of brown-headed cowbirds (a nest parasite) to the detriment of species such as willow flycatcher and yellow warblers.

·       Continued rock climbing could adversely affect crevice-roosting special-status species of bats, such as greater western mastiff bat.

·       Continued concentrated visitor use along the north side of the Merced River within Little Yosemite Valley could have site-specific, adverse effects on forest communities located north of the river and could have long-term, adverse effects on habitat for northern goshawk and Cooper's hawk at this location, as repeated disturbances near nest trees could result in nest failure or abandonment.

The degree to which rare, threatened, and endangered species would be affected depends on individual species habitat requirements, position relative to facilities and use, and sensitivity to perturbation. Special-status species that occur near Merced Lake High Sierra Camp and Backpackers Campground, Little Yosemite Valley Backpackers Campground, Moraine Dome Backpackers Campground, and major trail routes could experience adverse effects.

Under Alternative 1, implementation of the park's existing user capacity management program could have short-term, negligible, beneficial impacts on rare, threatened, and endangered species and the biological ORVs in Wilderness segments of the Merced River by reducing visitor effects on these sensitive resources. For example, trailhead quotas limit total overnight entries into wilderness areas of the park to 1,280 per day. Existing quotas based on resource protection goals also restrict the number of day users on both established trails and cross-country routes in wilderness areas to prevent degradation of high-elevation meadows and impacts to associated rare, threatened, and endangered species. However, visitor numbers are expected to increase, and Alternative 1 does not provide a means for monitoring adverse effects on special-status species and the biological ORVs or for implementing management actions (e.g., reducing trailhead quotas, limiting wilderness permits, or closing trails) to reduce adverse visitor-use impacts on these resources.

Under Alternative 1, wilderness areas would maintain wilderness zoning (1A, 1B, 1C, and 1D) and would continue to reflect current management practices and visitor use levels, based on the Wilderness Act, the Wilderness trailhead quota system, and the Merced River Plan. Management zoning and the River Protection Overlay limit the types of new facilities that could be built (e.g., large campsites with facilities are prohibited in zone 1B zone) potentially beneficially affecting special-status species. Future actions (e.g., trail rehabilitation) that could occur under the current zoning would be subject to the Merced River Plan's consistent set of criteria and considerations which require the protection of ORVs. The plans and policies would result in local, short- and long-term, negligible, beneficial effects on special-status species and the biological ORVs in the Wilderness segments.

A Wilderness Impacts Monitoring System (WIMS) began in the 1970s. Under WIMS, the park conducts wilderness-wide inventory and monitoring studies focused on campsite and trail impacts. The results of WIMS provides park management with a mechanism to monitor potential impacts to the river corridor through wilderness, and take corrective actions as appropriate to ensure that the river's ORVs are being protected and enhanced in these segments.

Overall, the application of management zoning and the other Merced River Plan elements, in combination with the trailhead quota system and WIMS would have a negligible effect on special-status species and the biological ORVs in the Wilderness segments.

Impacts in Yosemite Valley. Riparian areas and low-elevation meadows are the most productive communities in Yosemite Valley. The high quality and large extent of riparian, wetland, and other riverine areas provide rich habitat for river-related species, including special-status species, neotropical migrant songbirds, and bat species. These habitats and associated species are examples of biological ORVs in Yosemite Valley. Existing facilities and ongoing stock and visitor use would result in the contribution of adverse affects on these habitats and rare, threatened, and endangered species in the following ways:

·       Trampling of meadows (e.g., at the base of El Capitan) could have direct effects on rare plants, as well as habitat for ground-dwelling wildlife species (e.g., voles), therefore reducing the prey base for special-status raptors and owls.

·       Continued high visitor use and the presence of the stable in Yosemite Valley would promote brown-headed cowbirds to the detriment of species such as yellow warbler.

·       Riparian-dependent species (e.g., yellow warbler) would continue to be adversely affected by the overall amount of noise, traffic, and human presence at facilities such as North and Lower Pines Campgrounds and Camp 6.

·       Continued expansion of coniferous forests throughout Yosemite Valley could adversely affect wildlife species such as great-horned owl and yellow warbler and plant species such as sugar stick, boreal bedstraw, false pimpernel, azure penstemon, and ladies' tresses that depend on meadow and oak woodland habitats.

·       Introduced trout would continue to affect native rainbow trout strains. Bullfrogs would continue to affect special-status amphibians and could affect reintroduction efforts (e.g., for California red-legged frog).

·       Continued non-native predation, fragmentation of aquatic and floodplain habitats, use of nonmotorized watercraft, swimming, and fishing could adversely affect northwestern pond turtle.

·       Increased human presence and human-related effects associated with the use of facilities (e.g., night lighting, reduction of habitat, noise, erosion) would likely result in long-term, adverse effects on special-status bats, hawks, owls, and numerous other bird species in Yosemite Valley.

·       Alternative 1 could affect the success of reintroduction or recolonization efforts for such species as willow flycatcher and California red-legged frog, now extirpated from Yosemite Valley.

Under Alternative 1, Merced River Plan's management zoning, River Protection Overlay and other elements would further the protection of sensitive species. The existing pattern of development in Yosemite Valley was established long before the river's designation of Wild and Scenic. Although portions of the east Valley would remain developed and subject to facility and visitor-use effects, the existing Restricted Access Plan would continue to be implemented when visitor levels exceed the capacity of the park transportation infrastructure. Park management could also close areas that show unacceptable impacts to allow for restoration or to reduce the intensity of the adverse effects. In addition, current zoning and the River Protection Overlay preclude several types of new development (e.g., new campsites are not allowed in the Day Use zone at Cathedral Beach) that have the potential to adversely affect rare, threatened, and endangered species. Future actions that could occur under current zoning (e.g., bridge removal, construction of new campsites) would be subject to the Merced River Plan's consistent set of criteria and considerations which include the protection of ORVs. The application of existing facility-based user capacity management tools, management zoning, and the Merced River Plan's criteria and considerations in Yosemite Valley would have a local, long-term, minor, beneficial effect on rare, threatened, and endangered species and the biological ORVs.

In the long term, visitor numbers are expected to increase, resulting in adverse effects on special-status species (e.g., night lighting, reduction of habitat, noise, erosion). These effects are expected to be moderate in areas of high visitor use such as east Yosemite Valley and minor in lower use areas such as the western portion of Yosemite Valley. Alternative 1 does not provide a means for monitoring adverse effects on special-status species and the biological ORVs or for implementing management actions to reduce visitor-use impacts on these resources.

Although Alternative 1 does include some mechanisms for protecting special-status species and the biological ORVs in Yosemite Valley, local, short- and long-term, adverse effects to special-status species could occur as the result of increases in visitation and the lack of a monitoring and management program to prevent increased visitor-use effects. These local, long-term, adverse effects would be minor to moderate.

Impacts in the Gorge. ORVs of the Gorge segment include river-associated special-status species and diverse riparian areas that are largely undisturbed by humans. The majority of the Gorge segment is zoned 2A+, 2A, 2B, and 2D. With the exception of the Cascades area, the Gorge segment would continue to be relatively inaccessible, and visitor use is unlikely to increase. Gorge zoning precludes most types of new development (e.g., campgrounds and lodging, new roads) that have the potential to adversely affect rare, threatened, and endangered species. In addition, future actions that could occur under the current zoning would be subject to the Merced River Plan's consistent set of criteria and considerations, which require the protection of ORVs. Other existing user capacity policies and guidelines would also be used.

In the long term, visitor numbers under Alternative 1 are expected to increase, resulting in moderate, adverse effects on special-status species in areas of moderate visitor use such as the Cascades area. Alternative 1 does not provide a means for monitoring adverse effects on special-status species and the biological ORVs or for implementing follow-on management actions to reduce visitor-use impacts on these resources.

Overall, the application of zoning and the Merced River Plan's consistent set of criteria and considerations within the Gorge segment in combination with the lack of a monitoring and management program to prevent increased visitor-use effects would have a local, long-term, minor, adverse effect on special-status species and the biological ORVs in accessible portions of the Gorge segment.

Impacts in El Portal. Montane hardwood conifer is the dominant habitat type adjacent to riparian areas below Yosemite Valley. In El Portal, wildlife access among habitats has been affected for decades on the north side of the river by roads, residences, lodging, and other human activities and development. In contrast, habitats on the south side of the river are relatively pristine and free of human-built barriers, although some historic mining operations have occurred in this area. The quality of these north-facing habitats is recognized as an ORV in the El Portal area, potentially providing nesting/roosting and foraging habitat for numerous special-status bird and bat species. El Portal has a base zone of 2C, with large tracts zoned 3C. The El Portal segment of the river corridor boundary includes the 100-year floodplain or River Protection Overlay, whichever is greater, as adopted in the Merced River Plan.

Examples of how management zoning, the River Protection Overlay, and the criteria and considerations under the Merced River Plan would affect rare, threatened, and endangered species and the biological ORVs in El Portal are described below.

·       The Sand Pit in El Portal was once used to mine sand from the Merced River. Riparian vegetation, such as the host plant for the Valley elderberry longhorn beetle, as well as a recently identified population of Congdon's wooly sunflower exist at this site. Under its 2C zoning, the Sand Pit could be restored, which would allow natural processes to prevail at this location, enhance the aquatic habitat, and allow natural revegetation with riparian species, thus resulting in a local, moderate, beneficial effect on this ORV.

·       Portions of El Portal are zoned 3C (e.g., the Trailer Village, Old El Portal), which could allow additional development (e.g., employee residences in Yosemite Valley could be relocated to the El Portal Administrative Site). Potential development could have both short-term (e.g., construction-related) and long-term (e.g., night lighting, human presence, fire suppression in the vicinity of structures), minor to major, adverse effects on rare, threatened, and endangered species. Although the application of mitigation measures described in Appendix B would reduce impacts, long-term, minor to moderate, adverse effects on rare, threatened, and endangered species (e.g., conversion of upland woodland or scrub vegetation to developed facilities) would remain in these areas.

The application of management zoning, the River Protection Overlay, and the criteria and considerations under the Merced River Plan would help to protect and enhance rare, threatened, and endangered species and the biological ORVs in El Portal. The zoning in El Portal allows for road repair as well as additional development of park administration facilities, which could have short- and long-term, adverse effects on rare, threatened, and endangered species. The management elements and criteria and considerations (including the Section 7 determination process) would protect rare, threatened, and endangered species and the biological ORVs both within and outside the boundary.

In the long term, visitor numbers are expected to increase, resulting in minor to moderate, adverse effects on special-status species in areas of moderate day-visitor use such as in close proximity to the river. Alternative 1 does not provide a means for monitoring adverse effects on special-status species and the biological ORVs or for implementing management actions to reduce visitor-use impacts on these resources.

Although Alternative 1 includes the use of existing user capacity management tools, management zoning, and the consistent set of Merced River Plan criteria and considerations, the lack of a VERP monitoring and management program to prevent increased visitor-use effects would have a local, short- and long-term, minor to moderate, adverse effect on rare, threatened, and endangered species and the biological ORVs in accessible and developed portions of this segment.

Impacts in Wawona. Habitats along the South Fork--meadow, riparian, scrub and chaparral, and coniferous and deciduous forests--comprise nearly a full range of habitats that are intact and undisturbed by humans. The meadow and wetland communities of Wawona and the fishery along the South Fork are currently designated as biological ORVs. River-related special-status species in the Wawona segments include Wawona riffle beetle and willow flycatcher, a species indicative of an intact meadow-riparian complex.

The Wawona segments include developed areas such as the Wawona Golf Course and Wawona Picnic Area (2C), Wawona Campground (3A), Wawona Hotel (3B), and the Wawona maintenance facility (3C). These areas were developed well before the river was designated Wild and Scenic. Adverse effects to rare, threatened, and endangered species associated with developed areas include habitat fragmentation due to buildings, roads, and other development, trampling, social trails, vehicle and pedestrian noise, human presence and disturbance, and other visitor-use effects. These adverse effects are local, long term, and minor to moderate. However, the base zones within the South Fork in Wawona (1B, 2A, and 2B) preclude new development such as interpretive centers, food services, campgrounds and lodging, and day-visitor parking. This zoning results in a long-term, negligible, beneficial impact to rare, threatened, and endangered species and the biological ORVs.

Facilities within the River Protection Overlay, such as portions of Wawona Campground and a portion of the Wawona maintenance facility, are inconsistent with the River Protection Overlay and could be removed or relocated. This could increase opportunities for natural revegetation and restoration of riparian habitat, resulting in a local, long-term, minor, beneficial impact on streamside vegetation and special-status species. Local, short-term, negligible to minor, adverse effects to special-status species could occur during removal of any facilities from the River Protection Overlay. These adverse impacts would be reduced to a negligible intensity by application of mitigation measures described in Appendix B. Limits on facilities (management zoning and the River Protection Overlay) in combination with the application of a consistent set of decision-making criteria and considerations from the Merced River Plan would allow existing natural areas to remain relatively intact and would direct restoration and enhancement of degraded native habitats.

In the long term, visitor numbers are expected to increase, resulting in moderate, adverse effects on special-status species in the limited areas of high day-visitor use in Wawona. Alternative 1 does not include a VERP program for monitoring adverse effects on special-status species and the biological ORVs or for implementing follow-on management actions.

Overall, to the increase in park use under Alternative 1 and the lack of a VERP monitoring and management program to assess the effects of visitor use would have a local, long-term, minor to moderate, adverse impact on rare, threatened, and endangered species and the biological ORVs in those parts of Wawona most used by visitors.

Summary of Alternative 1 Impacts. Compliance with existing park policies and federal regulations such as the Endangered Species Act help ensure that the biological ORVs in each river segment are protected and enhanced. Under Alternative 1, management zoning and the River Protection Overlay would preclude various types of new development that have the potential to affect rare, threatened, and endangered species. In the long term, the combination of existing facility-based user capacity management tools, management zoning, the River Protection Overlay, and application of a consistent set of decision-making criteria and considerations from the Merced River Plan would have a negligible, beneficial effect on rare, threatened, and endangered species and the biological ORVs within the river corridor. These elements could preclude inappropriate development, remove inappropriate facilities from the immediate river corridor, subject new actions to a rigorous planning process designed to eliminate adverse effects on the ORVs, and manage zones to their desired conditions. This would allow existing natural areas to remain relatively intact and would direct restoration and enhancement of degraded native habitats.

Local, short- and long-term, adverse effects on special-status species could occur as the result of future actions that could be implemented under the proposed zoning (e.g., new campsites, parking facilities, road repair). In addition, because Alternative 1 does not include a VERP monitoring and management program to prevent increased visitor-use effects on special-status species and the biological ORVs, this alternative could result in adverse effects on rare, threatened, and endangered species. Under Alternative 1, four basic adverse impacts would continue to occur and are expected to worsen over time: degradation in habitat quality for riparian and wet-meadow-dependent rare, threatened, and endangered species; loss of habitat connectivity and increased habitat fragmentation; increased human-related disturbance; and continued stress on rare, threatened, and endangered species through factors such as the increasing presence of non-native species and disturbance-tolerant wildlife.

Overall, Alternative 1 would result in a local, long-term, minor to moderate, adverse impact on rare, threatened, and endangered species and the biological ORVs within the river corridor.

Cumulative Impacts

Cumulative effects to rare, threatened, and endangered species are based on analysis of past, present, and reasonably foreseeable actions in the Yosemite region in combination with potential effects of this alternative. The impact intensity would depend on whether the effects are expected to interact cumulatively. The projects identified below include those projects that have the potential to effect populations of rare, threatened, or endangered species (i.e., within the river corridor) as well as large-scale or regional populations of the same species.

Past Actions. Natural habitats have been manipulated almost since the establishment of the park. Regional wildlife and vegetation patterns have been historically affected by logging, fire suppression, rangeland clearing, grazing, mining, draining, damming, diversions, and the introduction of non-native species. Mammal species that survive but are extremely rare are the fisher, wolverine (possibly extinct), and Sierra Nevada red fox. Several bird species have probably been reduced in Yosemite Valley by visitor activity, but are present in less disturbed areas of the park. Willow flycatchers no longer nest in Yosemite Valley, probably due as much to parasitism by brown-headed cowbirds as to destruction of riparian and meadow habitat. Amphibians in Yosemite National Park have suffered population declines similar to those seen in the rest of the Sierra Nevada (Drost and Fellers 1996). Red-legged frogs likely were found in Yosemite Valley in the past but are now are presumed extirpated. Significant factors in their disappearance probably include reduction in perennial ponds and wetlands, and predation by bullfrogs. At higher elevations, mountain yellow-legged frogs and Yosemite toads are still present in a number of areas, but are severely reduced in population and range. Foothill yellow-legged frogs have disappeared completely from the park, if not the entire Sierra Nevada. Research continues to identify the causes of amphibian declines in the Sierra Nevada; possible causes include habitat destruction, non-native fish, pesticides, and diseases. Past and ongoing activities that affect rare, threatened, or endangered species include recreational use as well as the construction of dams, diversion walls, bridges, roads, pipelines, riprap, buildings, campgrounds, and other recreational features.

In 1991, the U.S. Forest Service and the Bureau of Land Management developed a joint South Fork and Merced Wild and Scenic River Implementation Plan for the segments of the main stem and South Fork of the Merced River that are under their jurisdiction. The plan is also a general management plan with many prescriptive goals and few actions. The plan endeavors to limit or end consumptive uses such as grazing within the river corridor and calls for the formalization of camping and launch facilities for nonmotorized watercraft. Implementation of these actions has a beneficial effect by eliminating impacts where feasible (grazing does not currently occur within the river corridor), concentrating impacts in areas able to withstand visitor use, and providing facilities that mitigate adverse effects associated with visitor use (e.g., restrooms).

Recently implemented projects have begun to reverse the centuries-long pattern of native vegetation and habitat degradation due to localized human uses in the region. These include:

·       Merced River Ecological Restoration at Eagle Creek

·       Happy Isles Fen Habitat Restoration

·       Cascades Diversion Dam Removal

These projects are expected to have local, long-term, moderate to major, beneficial effects on habitat and rare, threatened, and endangered species because they involve the restoration of previously degraded areas and thus enhance local and regional plant and wildlife species diversity. In addition to these specific projects, one of the major goals of the Yosemite Valley Plan is to restore, protect, and enhance the natural resources of Yosemite Valley. Actions set forth in the plan that result in beneficial effects on rare, threatened, and endangered species include the removal of roads, facilities, and services in the Valley (including roads through Stoneman Meadow and the southern portion of Ahwahnee Meadow, most parking areas in the east Valley, and commercial trail rides in the Valley), as well as the relocation of employee housing out of the Valley and the establishment of vegetation restoration objectives (expressed as acres per habitat type).

Other past projects that have likely had a beneficial, cumulative effect on regional habitat and special-status species include transportation-related projects, which have the general goal of increasing transportation options and reducing reliance on automobiles. In addition, the Fire Management Plan seeks to improve ecosystem health and restore meadows and therefore would have a regional, long-term, moderate to major, beneficial effect on Yosemite's rare, threatened, and endangered species and the biological ORVs throughout the Merced River corridor.

Present Actions. Present actions in the region have the potential to result in both beneficial and adverse effects on rare, threatened, and endangered species:

·       Current projects with net long-term, beneficial effects on rare, threatened, and endangered species (resulting from revegetation and habitat restoration efforts, control of competing invasive species, and improved air quality) include the Cook's Meadow Ecological Restoration, Happy Isles Dam Removal, Lower Yosemite Fall Project, Parkwide Invasive Plant Management Plan, Utilities Master Plan/East Yosemite Valley Utilities Improvement Plan, and Yosemite Valley Shuttle Bus Procurement.

·       Projects such as the Curry Village Employee Housing, Happy Isles to Vernal Fall Trail Reconstruction, South Fork Bridge Replacement, and Yosemite Motels Expansion could have short- and long-term, adverse effects on rare, threatened, and endangered species through construction-related, operational, and maintenance actions.

Reasonably Foreseeable Future Actions. Reasonably foreseeable future actions proposed in the region are separated below into three general categories: (1) projects anticipated to have a net beneficial effect; (2) projects anticipated to have both beneficial and adverse effects; and (3) projects anticipated to have a net adverse effect.

Examples of projects that could have a cumulative, beneficial effect on rare, threatened, and endangered species include:

·       Wawona Campground Rehabilitation

·       Update to the Yosemite Wilderness Management Plan

·       Red Peak Pass Trail Rehabilitation

·       Visitor Use and Floodplain Restoration Program

Although each of these projects could have slight local and short-term, adverse effects (e.g., construction-related effects), the general goal of these projects is to increase coordinated resource management and to restore sensitive ecosystems. Therefore, these projects could have a long-term, beneficial cumulative impact to regional rare, threatened, and endangered species. For example, the update to the Yosemite Wilderness Management Plan could result in additional restrictions on wilderness facilities and activities, reducing site-specific erosion and trampling and possibly stock use.

Reasonably foreseeable future actions that could have mixed adverse and beneficial effects on rare, threatened, and endangered species include:

·       Tuolumne Meadows Concept Plan

·       Tuolumne Wild and Scenic River Comprehensive Management Plan

·       Curry Village and East Yosemite Valley Campgrounds Improvements

·       El Portal Concept Plan

·       Yosemite Lodge Area Redevelopment

Cumulative effects of these projects could be mixed, combining both adverse and beneficial effects. The net beneficial or adverse effects of these projects are difficult to predict. For example, implementation of the Yosemite Lodge Area Redevelopment project has the potential to adversely affect rare, threatened, and endangered species during construction (short term), as well as permanently displace special-status species and habitat with the relocation of Northside Drive (long term); however, removing Yosemite Lodge facilities from the River Protection Overlay and floodplain would allow for revegetation and restoration of habitat within the Merced River corridor (long-term, beneficial effect). Adverse impacts associated with construction activities could be partially mitigated through project design and implementation of Best Management Practices, compliance monitoring, and restoration.

Reasonably foreseeable future actions that could have an adverse effect on rare, threatened, and endangered species include:

·       Environmental Education Campus Development Program

·       El Portal Road Improvements Project (Segment D)

·       Indian Cultural Center

·       Northside-Southside Drive Repaving

·       Out-of-Valley Campground Plan

·       Yosemite Village Interim Parking Improvements

Cumulative parkwide adverse effects would be related to increased facilities, access, and regional population growth. Each of these projects could have local, minor to major, adverse effects on rare, threatened, and endangered species during construction (short term) and due to direct displacement of resources (long term). Construction and human-use-related effects on rare, threatened, and endangered species include direct displacement of species, introduction of non-native species that invade into adjacent natural areas and displace native species, fragmentation of habitats that prevents genetic mixing, alteration of natural patterns, and increased erosion and sedimentation. Although each new development would be required to mitigate or compensate for adverse effects to rare, threatened, and endangered species, the mitigation would generally be uncoordinated and would not typically replace natural ecosystem functions or values that were present throughout the region prior to Euro-American settlement.

Past, present, and reasonably foreseeable future actions in the immediate vicinity of Yosemite National Park could have a long-term, minor, beneficial effect on rare, threatened, and endangered species and the biological ORVs within the Merced River corridor. Overall, these cumulative actions, in combination with Alternative 1 could have a net local, long-term, minor, adverse effect on parkwide rare, threatened, and endangered species and the biological ORVs of the Merced River corridor.

Impairment

Alternative 1 would have a local, long-term, minor to moderate, adverse effect on parkwide rare, threatened, and endangered species and the biological ORVs of the Merced River corridor and therefore has the potential to impair these resources for future generations.

Air Quality

Analysis

The following discussion provides an overview of the types of impacts to air quality that could occur within each segment of the Merced River corridor associated with Alternative 1. Alternative 1 includes application of the elements of the Merced River Plan (boundaries, classifications, ORVs, management zones and River Protection Overlay, and the Section 7 Determination process), and existing park management policies.

Under Alternative 1, air quality in the river corridor would continue to be influenced by local sources within the park and by regional sources upwind of the park. Local emissions sources include stationary, area, and mobile sources. Generally, the effects of local emissions sources would be limited to those areas (such as the Valley, the El Portal Administrative Site, and Wawona), where these sources are concentrated. Portions of the corridor that extend through wilderness areas would continue to be largely free of effects from local emissions sources (with the exception of prescribed fires) but would be subject to regionwide emissions trends.

Impacts in Wilderness. User capacity within wilderness areas of Yosemite National Park is currently addressed through the trailhead quota system and monitoring of wilderness resource conditions. Under Alternative 1, use of trails in wilderness areas would continue consistent with existing conditions. It is anticipated that annual day use of easily accessible wilderness areas (e.g., the trail to Half Dome) could increase with the projected increase in visitor demand. However, wilderness areas would continue to be largely free of effects from local emissions sources (with the exception of prescribed fires) but would be subject to regionwide emissions trends. Emissions from prescribed burning would continue to be controlled through implementation of smoke management policies in the 2004 Fire Management Plan; the current policies are intended to minimize impacts on air quality from prescribed burning within the park and region. The continuation of existing conditions would be expected to have local, long-term, negligible to minor, adverse impacts on air quality.

Impacts in Yosemite Valley. Under Alternative 1, air quality in Yosemite Valley would continue to be influenced by local sources within the park and by regional sources upwind of the park. The effects of local emissions sources are concentrated in the Valley. Emissions from local stationary sources, such as fossil-fuel-powered mechanical equipment, would continue to be regulated through applicable Mariposa County Air Pollution Control District Rules and Regulations.

Local area pollution sources would continue to include regular maintenance activities, campfires, woodstoves, fireplaces, prescribed fires, and vehicle entrainment of road dust. Some of these sources would continue in the same manner and extent as under existing conditions, while others would increase in relative proportion to visitor use levels. More specifically, in the short-term, visitor levels would remain approximately the same as existing levels. Over the long-term, visitor numbers could increase somewhat over time, but such increases would be constrained by existing facility levels.

Regular maintenance-related activities would result in temporary increases in emissions of particulate matter in the immediate vicinity of such activities. Campfires, woodstoves, and fireplaces would continue to be subject to park regulations, and related emissions would not be expected to increase because the number of campsites and housing (where campfires, woodstoves, and fireplaces are used) would remain much the same under this alternative as under existing conditions and because campsites and housing are already full most of the year. Campfire-, woodstove-, and fireplace-related emissions would continue to affect air quality and visibility within the Valley under certain meteorological conditions. Emissions from prescribed burning would continue to be controlled through implementation of smoke management policies in the 2004 Fire Management Plan, as discussed above. Emissions from vehicle entrainment of road dust would continue to affect air quality, particularly in winter and early spring when drying road surfaces expose sand deposited for traction to vehicle entrainment into the atmosphere. Over the long term, road dust would increase in rough proportion to the number of vehicle-miles traveled within the park.

Local mobile sources would continue to include automobiles, trucks, and buses and would remain subject to state and federal emissions control standards and programs, which are expected to lead to a continuing decrease in emissions per vehicle-mile-traveled for the foreseeable future due to continued motor vehicle fleet turnover, cleaner burning fuels, and improved combustion technologies. In the future, the number of vehicles in the Valley on typically busy days would essentially be the same as under existing conditions; however, on an average basis, the number of vehicles would increase in rough proportion to the number of annual visitors. In general, the downward trend in emissions of ozone precursors per vehicle and per vehicle-miles traveled would more than offset the long-term incremental increase in the number of annual vehicle trips within the Valley. Based on composite vehicle emissions factors derived from data published by the state Air Resources Board, the anticipated reduction in emissions per vehicle-mile would be approximately 85% for volatile organic compounds and 75% for nitrogen oxides between existing 2004 conditions and 2020. Because the increase in vehicle-miles traveled in the Valley would be less than 75% in 2020 relative to existing conditions, these reductions in emissions per vehicle-mile would offset any increases in emissions associated with increases in annual visitors. Volatile organic compounds and nitrogen oxides are precursor compounds associated with ozone formation. However, in contrast to the ozone precursors, most of the particulate matter associated with vehicle use is related to entrainment of road dust rather than to exhaust. Thus, as explained above, particulate emissions would be expected to increase over the long term in rough proportion to the number of vehicle-miles traveled within the Valley. With respect to ozone precursors, overall local emissions in Yosemite Valley under Alternative 1 would follow the regional downward trend relative to existing conditions (as a result of more efficient vehicle engines and continued vehicle fleet turn-over), which would represent a regional, long-term, minor, beneficial effect. With respect to particulate matter, overall local emissions in Yosemite Valley under Alternative 1 could increase relative to existing conditions, resulting in a local, long-term, minor, adverse effect.

Impacts in the Gorge. Under Alternative 1, areas zoned Untrailed (1A), Open Space and Undeveloped Open Space (2A, 2A+), and Discovery (2B) in the Gorge segment would continue to be free of effects from local emissions sources but would be subject to regionwide emissions trends. Emissions from prescribed burning would continue to be controlled through implementation of smoke management policies in the 2004 Fire Management Plan. In the short term, user levels would remain approximately the same as existing levels. Over the long term, user numbers could increase somewhat over time, but such increases would be constrained by existing facility levels. Areas zoned Day Use (2C), Attraction (2D), and Park Operations and Administration (3C) would continue to experience a local, long-term, minor, adverse effect due to the concentration of vehicular emissions in those areas.

Impacts in El Portal. Under Alternative 1, the boundary for the El Portal segment would remain the same as that shown in the 2000 Merced River Plan. This boundary does not account for precise locations of El Portal ORVs; however, air quality is not listed as an ORV along any of the river segments, including El Portal. Under Alternative 1, management zoning in the El Portal segment of the river corridor would be limited to Day Use (2C) and Park Operations and Administrative (3C) zoning. The base zone through much of this segment is Day Use (2C). In the short term, visitor levels would remain approximately the same as existing levels. Over the long term, visitor numbers could increase somewhat over time, but such increases would be constrained by existing facility levels. These areas would continue to experience a local, long-term, minor, adverse effect due to the concentration of vehicular emissions in those areas.

Impacts in Wawona. Under Alternative 1, air quality in Wawona would continue to be influenced by local sources within the park and by regional sources upwind of the park. The effects of local emissions sources are concentrated in Wawona. Emissions from local stationary sources, such as fossil-fuel-powered mechanical equipment, would continue to be regulated through applicable Mariposa County Air Pollution Control District Rules and Regulations.

Local area pollution sources would continue to include regular maintenance activities, campfires, woodstoves, fireplaces, prescribed fires, and vehicle entrainment of road dust. Some of these sources would continue in the same manner and extent as under existing conditions, while others would increase in relative proportion to visitor use levels. In the short term, user levels would remain approximately the same as existing levels. Over the long term, user numbers could increase somewhat over time, but such increases would be constrained by existing facility levels.

Regular maintenance-related activities would result in temporary increases in emissions of particulate matter in the immediate vicinity of such activities. Campfires, woodstoves, and fireplaces would continue to be subject to park regulations, and related emissions would not be expected to increase because the number of campsites and housing would remain much the same under Alternative 1 as under existing conditions and because campsites and housing are already full most of the year. Campfire-, woodstove-, and fireplace-related emissions would continue to affect air quality and visibility within the Wawona area under certain meteorological conditions. Emissions from prescribed burning would continue to be controlled through implementation of smoke management policies in the 2004 Fire Management Plan. Emissions from vehicle entrainment of road dust would continue to affect air quality, as discussed in previous sections. Road dust would increase in rough proportion to the number of vehicle-miles traveled within the park.

Local mobile sources would continue to include automobiles, trucks, and buses and would remain subject to state and federal emissions control standards and programs, which are expected to lead to a continuing decrease in emissions per vehicle-mile-traveled for the foreseeable future. In the future, the number of vehicles in Wawona on typically busy days would be essentially the same as under existing conditions; however, the number of days during which the plan would be in effect would increase, and, on an average basis, the number of vehicles would increase in rough proportion to the number of annual visitors. In general, the downward trend in emissions of ozone precursors per vehicle would more than offset the long-term incremental increase in the number of annual vehicle trips within Wawona. As discussed above, the anticipated reduction in emissions per vehicle-mile would decrease dramatically for ozone precursor compounds between existing 2004 conditions and 2020. However, in contrast to the ozone precursors, most of the particulate matter associated with vehicle use is related to entrainment of road dust rather than to exhaust. Thus, as explained above, particulate emissions would be expected to increase in the future in rough proportion to the number of vehicle-miles traveled within Wawona. With respect to ozone precursors, overall local emissions in Wawona under Alternative 1 would follow the regional downward trend relative to existing conditions, which would represent a regional, long-term, minor, beneficial effect. With respect to particulate matter, overall local emissions in Wawona under Alternative 1 could increase relative to existing conditions, resulting in a local, long-term, minor, adverse effect.

Summary of Alternative 1 Impacts. Under this alternative, air quality in the corridor would continue to be influenced by local pollution sources within the park and by regional sources upwind of the park. The relative importance of local and regional sources would continue to vary by season and by pollutant. Furthermore, nonwilderness portions of the corridor would be affected by local emissions sources to a much greater extent than wilderness portions. Local stationary sources would continue to be regulated under Mariposa County Rules and Regulations; some local area sources would continue to be subject to park regulations; and mobile sources would continue to be subject to state and federal tailpipe emissions standards.

With respect to ozone precursors, overall local emissions under Alternative 1 would follow the regional downward trend relative to existing conditions regardless of potential increases in long-term visitor levels, which would be a regional, long-term, minor, beneficial effect. With respect to particulate matter, overall local emissions under Alternative 1 could increase relative to existing conditions, resulting in a local, long-term, minor, adverse effect, because that pollutant is more closely linked to overall vehicle-miles traveled, which would increase over the long term, than to tailpipe exhaust emissions, which would decrease.

Cumulative Impacts

Cumulative effects to air quality are based on analysis of past, present, and reasonably foreseeable actions in the Yosemite region in combination with potential effects of this alternative. The projects identified below include only those projects that could affect air quality within the river corridor or that could be affected by air pollutant sources within the river corridor.

Past Actions. Since 1950, the population of California has tripled, and the rate of increase in vehicle-miles traveled has increased sixfold. Air quality conditions within Yosemite National Park have been influenced by this surge in population growth and its associated emissions from related industrial, commercial, and vehicular sources in upwind areas as tempered by a burgeoning regulatory apparatus. Since the 1970s, emissions sources operating within the park, as well as California as a whole, have been subject to local stationary-source controls and state and federal mobile-source controls. With the passage of time, such controls have been applied to an increasing number of sources, and the associated requirements have become dramatically more stringent and complex. In the 1980s, restricted access policies were developed for use when traffic and parking conditions in Yosemite Valley become too congested. These policies have the effect of reducing the number of incoming vehicles and their related emissions until the traffic volume and parking demand in Yosemite Valley decrease sufficiently (as departing visitors leave the Valley) to stabilize traffic conditions.

Recent past project-specific actions that did not have a net adverse or beneficial effect on air quality, other than localized, short-term, moderate to major, adverse impacts due to construction activities, include:

·       Infrastructure projects, such as Cascades Diversion Dam Removal; and Happy Isles Gauging Station Bridge Removal.

·        Several trail and resource restoration projects, such as the Happy Isles Fen Habitat Restoration and the Merced River Ecological Restoration at Eagle Creek.

The El Portal Road Improvements Project, Segments A, B, and C had both locally adverse (short term during construction) and potentially regionally beneficial (long-term) effects on air quality. Short-term, construction-related effects included dust and other pollutant emissions associated with operation of construction equipment, earthmoving activities, and vehicle travel over unpaved surfaces. The safety improvements on Segments A, B, and C of El Portal Road facilitate regional transit service on that route, which could have a regional, long-term, minor, beneficial impact by reducing automobile trips.

Adoption of the 2000 Yosemite Valley Plan is another past project that could have a cumulative, beneficial, long-term effect on air quality. The Yosemite Valley Plan proposes to enhance the quality of the visitor experience in the Valley by reducing automobile congestion, limiting crowding, and expanding orientation and interpretation services. It also proposes traffic management systems and options for the size and placement of parking lots, both within and outside Yosemite Valley. Parking lot(s) outside the Valley could be used to intercept day visitors and shift those visitors to Valley-bound, hybrid diesel-electric shuttle buses.

Examples of past projects that could have a net cumulative, long-term, adverse effect on air quality include the 2004 Fire Management Plan, which could lead to increased use of prescribed burning techniques and could have an intermittent, long-term, adverse effect on local and regional air quality and visibility, depending on the extent to which it protects air resources.

Present Actions. Present actions in the region are separated below into three general categories: (1) projects anticipated to have a net long-term beneficial effect; (2) projects anticipated to have a net adverse, long-term effect; and (3) projects not anticipated to have a net adverse or beneficial, long-term effect.

Examples of current projects that could have a cumulative, long-term, beneficial effect on air quality include:

·       Yosemite Valley Shuttle Bus Procurement, which replaces the existing fleet of 1986 diesel buses servicing Yosemite Valley with a new fleet of hybrid electric-diesel buses with lower emissions and greater fuel efficiency

·       Yosemite Valley Shuttle Bus Stop Improvements, which promotes and improves the relative attractiveness of bus use

·       Resource Management Building and the Curry Village Employee Housing, both of which reduce work/home commutes for some employees

Although the Yosemite Valley Shuttle Bus Stop Improvements Project has localized, short-term adverse effects (e.g., construction-related effects) associated with its implementation, its general goal is to improve regional transportation, circulation, and safety. Together, these bus-related projects would, individually and in combination, encourage travel to the park by alternative (non-private vehicle) modes and would have a long-term, beneficial effect on air quality.

Examples of current projects that could have a net cumulative, long-term, adverse effect on air quality include various development-related projects, such as the Yosemite Motels Expansion and the Mariposa County General Plan Update. Cumulative growth in the region would have localized, short-term, construction-related impacts; over the long term, these projects would generate emissions of ozone precursors and particulate matter primarily due to associated motor vehicle trips.

Examples of current projects that are not anticipated to have a net adverse or beneficial effect on air quality, other than short-term, localized impacts due to construction activities, include:

·       Infrastructure plans and projects, such as the Cook's Meadow Ecological Restoration, Happy Isles Dam Removal, Lower Yosemite Fall Project, Replacement/ Rehabilitation of Yosemite Valley Sewer Line, Utilities Master Plan/East Yosemite Valley Utilities Improvement Plan, and South Fork Bridge Replacement.

·       Several trail and resource restoration plans and projects, such as the Happy Isles to Vernal Fall Trail Reconstruction and the Parkwide Invasive Plant Management Plan

Reasonably Foreseeable Future Actions. Reasonably foreseeable future actions proposed in the region are also separated below into three general categories: (1) projects anticipated to have a net beneficial, long-term effect; (2) projects anticipated to have a net adverse, long-term effect; and (3) projects not anticipated to have a net adverse or long-term, beneficial effect.

Examples of projects that could have a cumulative, long-term, beneficial effect on air quality include:

·       Tuolumne Meadows Concept Plan

·       Tuolumne Wild and Scenic River Management Plan

·       Update to the Yosemite Wilderness Management Plan

Although projects allowed for under these plans could have localized, short-term adverse effects (e.g., construction-related effects), the general goal of each of these plans is to protect and enhance resources, including air resources, in Yosemite National Park. As such, these plans would be expected to have long-term, beneficial, effect on air quality.

Reasonably foreseeable future actions that could have a net cumulative, long-term, adverse effect on air quality include:

·       El Portal Concept Plan

·       Yosemite campground plans and projects that could increase the number of available campsites, such as the Curry Village and East Yosemite Valley Campground Improvements and Out-of-Valley Campground Plan.

·       Various development-related projects, such as the Environmental Education Campus Development Program, Indian Cultural Center, and the Yosemite Lodge Area Development.

The Curry Village and East Yosemite Valley Campground Improvements and the Out-of-Valley Campground Plan could construct additional campsites, which could result in increased local emissions from campfires, unless these projects were to provide for group fire rings rather than fire rings at each campsite.

Cumulative growth in the region would have localized, short-term, construction-related impacts; over the long term, these projects would generate emissions of ozone precursors and particulate matter primarily due to associated motor vehicle trips.

Reasonably foreseeable future actions not anticipated to have a net adverse or beneficial effect on air quality, other than short-term, localized impacts due to construction activities, include:

·        Infrastructure and transportation projects, such as the El Portal Road Improvements Project and the Northside-Southside Drive Repaving

·        Yosemite campground rehabilitation and parking improvement projects, such as the Wawona Campground Rehabilitation; and Yosemite Village Interim Parking Improvements

·        Trail restoration projects, such as the Red Peak Pass Trail Rehabilitation

·        The Visitor Use and Floodplain Restoration Program

Many of the above-noted cumulative projects would result in local, short-term, major, adverse effects on air quality due to construction activities, and, in some cases, these effects would occur within the Merced River corridor. With respect to long-term effects, a distinction can be made between ozone and particulate matter. For ozone, regional emissions trends suggest that the combination of the beneficial effect of ongoing regional, state, and federal regulatory controls (particularly mobile-source control programs) with the adverse effect of existing and future land use development and associated stationary, area, and mobile emissions sources, would result in a regional, long-term, moderate, beneficial effect. That is, the beneficial effect of past and present actions that regulate stationary and mobile emissions sources and reasonably foreseeable future actions that have the potential to reduce vehicle trips and vehicle-miles traveled would offset the adverse effect of ozone precursor emissions associated with increased cumulative growth in the region, leading to a gradual improvement in ozone air quality.

For particulate matter, the net cumulative effect is more difficult to determine because ambient concentrations of particulate matter reflect primary (i.e., directly emitted) particles as well as secondary (i.e., derived through photochemical reactions involving precursor pollutants) particles derived from emissions of volatile organic compounds, nitrogen oxides, and sulfur oxides. One of the principal sources of directly emitted particles is entrainment of dust by vehicles moving over paved roads, and this component of particulate matter would increase in proportion to increases in vehicle-miles traveled associated with cumulative growth. One of the secondary sources of particulate matter, sulfur oxides, would also continue to increase with cumulative growth. In contrast, as discussed above in connection with ozone, emissions of volatile organic compounds and nitrogen oxides would continue a downward trend despite cumulative growth, and thus, their contribution to particulate matter concentrations would diminish. Furthermore, unlike ozone, which is considered a regional pollutant, particulate matter reflects both local and regional sources, and the relative influence of these two basic types of sources changes from day to day. Thus, given the opposing emissions trends and the varying relative contributions of regional and local emissions sources, it would be speculative to conclude that the cumulative effect relative to particulate matter would be beneficial or adverse; however, the opposing emissions trends would tend to diminish the magnitude of the effect, regardless of whether the effect would be beneficial or adverse.

Since Alternative 1 would not involve any substantial construction projects, the local, short-term, major, adverse effects on air quality due to construction activities that are cited above would be due to the cumulative projects. Over the long term, with respect to ozone, conditions in the corridor would be determined almost entirely by regional emissions trends rather than by local emissions sources under Alternative 1; as discussed above, the long-term, regional effect would be beneficial, primarily due to the emissions reductions expected to occur with implementation of ongoing state and federal mobile-source control programs. With respect to particulate matter, conditions in the river corridor would be determined by both regional sources and local sources, and the relative influence of these two types of sources would vary from day to day and season to season. Given the opposing emissions trends between primary and secondary sources of particulate matter and the varying relative contributions of regional and local emissions sources, it would be speculative to conclude that the combined effect of cumulative actions and Alternative 1 would be beneficial or adverse with respect to particulate matter; however, opposing emissions trends would tend to diminish the magnitude of the effect, regardless of whether the effect would be beneficial or adverse.

Impairment

With respect to ozone precursors, overall local emissions under Alternative 1 would follow the regional downward trend relative to existing conditions, which would represent a regional, long-term, minor, beneficial effect. With respect to particulate matter, overall local emissions under Alternative 1 could increase relative to existing conditions, resulting in a local, long-term, minor, adverse effect. Overall, implementation of Alternative 1 would not impair air quality in the park.

Noise

Analysis

The following discussion provides an overview of the types of impacts to the ambient noise environment associated with Alternative 1 that could occur within each segment of the Merced River corridor. Alternative 1 provides a baseline for comparing existing conditions in the Merced River corridor with each action alternative. Alternative 1 includes the application of the elements of the Merced River Plan (boundaries, classifications, ORVs, management zones and River Protection Overlay, and the Section 7 Determination process), as well as the elements of the February 2004 User Capacity Management Program, and other park policies. However, Alternative 1 does not include full implementation of the VERP program.

Natural quiet is not listed as an ORV along any of the river segments. However, one important aspect of this environmental condition - the enjoyment of natural river sounds - is integrated into the recreation ORVs for three segments of the river, two segments in designated Wilderness (the wilderness of the main stem and the South Fork of the Merced River) and also the area below Wawona. That aspect would continue to be considered for protection and enhancement in those areas. Generally, policies and actions that protect and enhance natural quiet in the corridor arise not from the Wild and Scenic Rivers Act, but from such documents as the 1989 Yosemite Wilderness Management Plan (NPS 1989b) and Reference Manual RM 47 Soundscape Preservation and Noise Management (NPS 2003b).

Under Alternative 1, the acoustical environment in wilderness areas would generally continue to be shaped largely by natural sources of sound punctuated by intrusive noise generated by high-altitude aircraft overflights. The acoustical environment in nonwilderness areas would generally continue to be shaped by human-caused sources of noise, such as vehicles and recreational activities, and by natural sources of sound, such as rushing water and wind. A parkwide monitoring effort in 1994 documented that aircraft could be heard 54% of the time in quiet areas (NPS 1994f). Non-aircraft noise can also be heard at other popular wilderness destinations close to developed areas and roads, such as wall and rims of the Valley.

Impacts in Wilderness. The enjoyment of natural river sounds is integrated into the recreation ORVs in designated Wilderness (the wilderness areas of the main stem and the South Fork of the Merced River). That aspect would continue to be considered for protection and enhancement in wilderness areas.

User capacity within wilderness areas of Yosemite National Park is addressed through the trailhead quota system and monitoring of wilderness resource conditions. Under Alternative 1, use of trails in wilderness areas would continue consistent with existing conditions. It is anticipated that annual day use of easily accessible wilderness areas (e.g., the trail to Half Dome) could increase with the projected increase in user demand.

In some wilderness areas, high-altitude aircraft overflights would continue to be the principal source of adverse noise impacts. Noise from overflights, which is an issue that is national in scope, may worsen over the long term, if there continues to be an upward national trend in the number of aircraft flights. The permit system under the Wilderness Management Plan would continue to minimize the noise associated with visitor use in wilderness areas by restricting the number of overnight visitors. The continuation of existing conditions would be expected to have local, long-term, negligible, adverse impacts on the ambient noise environment.

Impacts in Yosemite Valley. Under Alternative 1, the acoustical environment in the Yosemite Valley segment of the river corridor would generally continue to be shaped by human-caused sources of noise and by natural sources of sound. Local conflicts between noise-sensitive uses and vehicular noise would continue to occur over the long term and would increase in severity due to the expected cumulative increase in visitation levels and related vehicular activity.

More specifically, in the short term, visitor levels would remain approximately the same as existing levels. Over the long term, visitor numbers could increase somewhat over time, but such increases would be constrained by existing facility levels. The gradual increase in visitation and related vehicular traffic would lead to an incremental increase in roadside noise levels. On typically busy days, roadside noise levels would be essentially the same as under existing conditions, since the same relative number of visitors would be allowed to travel to the Valley.

Developed areas of Yosemite Valley would continue to experience a local, long-term, minor, adverse effect due to the concentration of vehicular noise and human activity in this area.

In both wilderness and nonwilderness areas of the Valley, maintenance activities (e.g., helicopter use in support of park operations) would continue under this alternative, and such activities would result in local, short-term, minor, adverse noise impacts, but it would be speculative to conclude that such activities would increase or decrease in frequency or duration.

Impacts in the Gorge. Under Alternative 1, the acoustical environment in areas of the Gorge segment of the river corridor zoned 1A, 2A, 2A+, and 2B would continue to be shaped largely by natural sources of sound punctuated by intrusive noise generated by high-altitude aircraft overflights and distant roadway noise. The acoustical environment in areas zoned 2C, 2D and 3C would continue to be shaped by human-caused sources of noise and by natural sources of sound. Local conflicts between noise-sensitive uses and vehicular noise would continue to occur over the long term and would increase in severity due to the expected cumulative increase in visitation levels and related vehicular activity.

In the short term, visitor levels would remain approximately the same as existing levels. Over the long term, visitor numbers could increase somewhat over time, but such increases would be constrained by existing facility levels. The gradual increase in visitation and related vehicular traffic would lead to an incremental increase in roadside noise levels. On typically busy days, roadside noise levels would be essentially the same as under existing conditions, since the same relative number of visitors would be allowed to travel to the Valley. Areas zoned 2C, 2D and 3C would continue to experience a local, long-term, minor, adverse effect due to the concentration of vehicular noise in those areas.

Impacts in El Portal. Under Alternative 1, the boundary for the El Portal segment of the river corridor would remain the same as that shown in the Merced River Plan, which would remain a the 100-year floodplain or River Protection Overlay, whichever is greater. This boundary does not account for precise locations of El Portal ORVs; "natural quiet" is not listed as an ORV along any of the river segments. One important aspect of this environmental condition - the enjoyment of natural river sounds - is integrated into the recreation ORVs, but is not applicable to this segment of the river. As such, policies and actions that protect and enhance natural quiet in this segment would continue to do so regardless of the boundary location.

Under Alternative 1, management zoning in the El Portal segment of the corridor would be limited to 2C and 3C zoning. The base zone through much of this segment would be Day Use (2C). The acoustical environment in these areas would continue to be shaped by human-caused sources of noise and by natural sources of sound. Local conflicts between noise-sensitive uses and vehicular noise would continue to occur over the long term and would increase in severity due to the expected cumulative increase in visitation levels and related vehicular activity.

In the short term, visitor levels would remain approximately the same as existing levels. Over the long term, visitor numbers could increase somewhat over time, but such increases would be constrained by existing facility levels. The gradual increase in visitation and related vehicular traffic would lead to an incremental increase in roadside noise levels. On typically busy days, roadside noise levels would be essentially the same as under existing conditions, since the same relative number of visitors would be allowed to travel to the Valley. These areas would continue to experience a local, long-term, minor adverse effect due to the concentration of vehicular noise and human activity in this area.

Impacts in Wawona. Under Alternative 1, the acoustical environment in the Wawona segments of the river corridor would generally continue to be shaped by human-caused sources of noise and by natural sources of sound. Local conflicts between noise-sensitive uses and vehicular noise would continue to occur over the long term and would increase in severity due to the expected cumulative increase in visitation levels and related vehicular activity.

In the short term, visitor levels would remain approximately the same as existing levels. Over the long term, visitor numbers could increase somewhat over time, but such increases would be constrained by existing facility levels. The gradual increase in visitation and related vehicular traffic would lead to an incremental increase in roadside noise levels. On typically busy days, roadside noise levels would be essentially the same as under existing conditions, since the same relative number of visitors would be allowed to travel to the Valley. Wawona would continue to experience a local, long-term, minor, adverse effect due to the concentration of vehicular noise and human activity in this area.

In both wilderness and nonwilderness areas of Wawona, maintenance activities (e.g., helicopter use in support of park operations) would continue under this alternative, and such activities would result in local, short-term, minor, adverse noise impacts, but it would be speculative to conclude that such activities would increase or decrease in frequency or duration.

Summary of Alternative 1 Impacts. The acoustical environment in wilderness areas would not be affected by Alternative 1, but would continue to be shaped largely by natural sources of sound punctuated by intrusive noise generated by high-altitude aircraft overflights. The acoustical environment in nonwilderness areas would continue to be shaped by human-caused sources of noise and by natural sources of sound. Alternative 1 would accommodate a gradual increase in annual visitation (higher use on non-peak days), which could lead to a local, long-term, negligible to minor, adverse effect along the various roads that traverse the corridor in nonwilderness areas.

Cumulative Impacts

Cumulative effects to the ambient noise environment are based on analysis of past, present, and reasonably foreseeable actions in the Yosemite region in combination with potential effects of this alternative. The projects identified below include only those projects that could affect noise within the river corridor or could be affected by noise sources within the corridor.

Past Actions. Development of facilities that include various sources of noise has occurred in and near some segments of the river corridor. Such facilities include roadways, campgrounds, lodging, and administrative buildings. Generally, these facilities were developed with limited consideration of potential noise impacts. From a regulatory standpoint, relevant state and federal noise standards typically apply to individual types of noise sources, such as automobiles and buses, rather than to overall noise levels, but the National Park Service has adopted policies (restricted access policies and the Wilderness Management Plan) that indirectly affect overall noise levels in the river corridor. The restricted access policies were developed for use when traffic and parking conditions in Yosemite Valley are congested. The plan has the indirect effect of limiting the amount of vehicle noise during peak periods by restricting the number of incoming vehicles until the traffic volume and parking demand in Yosemite Valley decrease sufficiently (as departing visitors leave the Valley) to stabilize traffic conditions.

The Wilderness Management Plan was developed to preserve a wilderness environment in which the natural world along with the processes and events that shape it are largely untouched by human interference. Implementation of the permit system for overnight camping under the Wilderness Management Plan reduces potential noise impacts in those areas where natural quiet is an important element of the visitor experience.

Recent past project-specific actions that did not have a net adverse or beneficial effect on the ambient noise environment, other than localized, short-term, moderate to major, adverse impacts due to construction activities, include:

·       Infrastructure projects, such as Cascades Diversion Dam Removal, and Happy Isles Gauging Station Bridge Removal.

·       Several trail and resource restoration projects, such as Happy Isles Fen Habitat Restoration, and Merced River Ecological Restoration at Eagle Creek. El Portal Road Improvements Project, Segments A, B, and C had both locally adverse (short-term during construction) and beneficial (long-term) effects on noise. Short-term, construction-related effects included noise from heavy equipment operations. The safety improvements on Segments A, B, and C of El Portal Road facilitate regional transit service on that route, which could have a local, long-term, negligible to minor, beneficial impact by replacing automobile trips with a smaller number of transit vehicle trips, depending on transit ridership levels.

Examples of past planning efforts that could have a net cumulative, local, long-term, adverse effect on the ambient noise environment include:

·       The Fire Management Plan, which could lead to increased use of prescribed burning techniques and localized noise impacts associated with heavy machinery use.

Adoption of the 2000 Yosemite Valley Plan is another past project that could have a net long-term, beneficial effect on the ambient noise environment. The Yosemite Valley Plan proposes to enhance the quality of the visitor experience in Yosemite Valley by reducing automobile congestion, limiting crowding, and expanding orientation and interpretation services. It also proposes traffic management systems and options for the size and placement of parking lots, both within and outside Yosemite Valley. Parking lot(s) outside the Valley could be used to intercept day visitors and shift those visitors to Valley-bound shuttle buses.

Present Actions. Present actions in the region are separated below into three general categories: (1) projects anticipated to have a net beneficial, long-term effect; (2) projects anticipated to have a net adverse, long-term effect; and (3) projects not anticipated to have a net adverse or beneficial, long-term effect.

Examples of current projects that could have a cumulative, beneficial, long-term effect on the ambient noise environment include:

·       Yosemite Valley Shuttle Bus Procurement, which replaces the existing fleet of 1986 diesel buses servicing Yosemite Valley with a new fleet of low-noise hybrid electric-diesel buses with noticeably quieter operations.

·       Yosemite Valley Shuttle Bus Stop Improvements, which will improve the relative attractiveness of bus use, thereby reducing private automobile trips.

·       Resources Management Building and Curry Village Employee Housing, both of which will reduce in-Valley vehicle trips for some employees.

Although most of the aforementioned projects would have localized, short-term, adverse effects (e.g., construction-related effects), the general goal of these projects is to improve regional transportation, circulation, and safety and to reduce private automobile use. Together, these projects would, individually and in combination, reduce private automobile use and would therefore have a long-term, beneficial effect on the ambient noise environment.

To the extent that the bus-related projects cited above would replace automobile trips in the Valley with bus trips, the anticipated beneficial effect would depend upon ridership levels (and the corresponding number of automobile trips that would be avoided). The new buses are noticeably quieter than typical diesel-powered buses. Thus, these projects have the potential to contribute to a cumulative beneficial effect in the Valley, but also have the potential to offset some of the benefit with low ridership levels.

Examples of current projects that could have a net cumulative, local, long-term, adverse effect on the ambient noise environment include:

·       Various development-related projects, such as Yosemite Motels Expansion; and the Mariposa County General Plan (Update).

Cumulative growth in the region would have localized, short-term, construction-related impacts; over the long term, these projects would have an adverse effect on local roadside noise levels due to increased vehicle trips.

Examples of current projects that are not anticipated to have a net adverse or beneficial effect on the ambient noise environment, other than short-term, localized impacts due to construction activities, include:

·       Infrastructure projects, such as Happy Isles Dam Removal; Lower Yosemite Fall; Replacement/Rehabilitation of Yosemite Valley Force Main Sewer Line; Utilities Master Plan/East Yosemite Valley Utilities Improvement Plan; Rehabilitate Yosemite Valley Campground Restrooms; and South Fork Bridge Replacement.

Several trail and resource restoration plans and projects, such as Cook's Meadow Ecological Restoration; Happy Isles to Vernal Fall Trail Reconstruction; Merced River Canyon Trail Acquisition; and Parkwide Invasive Plant Management Plan.

Reasonably Foreseeable Future Actions. Reasonably foreseeable future actions proposed in the region are separated below into three general categories: (1) projects anticipated to have a net beneficial, long-term effect; (2) projects anticipated to have a net adverse, long-term effect; and (3) projects anticipated not to have a net adverse or net beneficial, long-term effect.

Cumulative projects that could have a net, long-term, beneficial effect on the ambient noise environment include:

·       Tuolumne Meadows Concept Plan.

·       Tuolumne Wild and Scenic River Comprehensive Management Plan.

·       Update to the Yosemite Wilderness Management Plan.

Although projects allowed for under these plans could have localized, short-term adverse effects (e.g., construction-related effects), the general goal of each of these plans is to protect and enhance conditions and resources, including addressing noise issues, in areas of Yosemite National Park. As such, these plans would be expected to have a beneficial, long-term effect on the ambient noise environment.

Reasonably foreseeable future actions that could have a net cumulative, long-term, adverse effect on the ambient noise environment include:

·       El Portal Concept Plan.

·       Yosemite campground projects and plans that could expand campgrounds, such as Curry Village and East Yosemite Valley Campground Improvements; and Out-of-Valley Campground Plan.

·       Various development-related projects, such as Environmental Education Campus Development Program; Indian Cultural Center; and Yosemite Lodge Area Development.

Curry Village and East Yosemite Valley Campground Improvements and Out-of-Valley Campground Plan could expand existing campgrounds, which could result in increased localized noise impacts.

Cumulative growth in the region, would have localized, short-term, construction-related impacts; over the long term, these projects would have an adverse effect on local roadside noise levels due to increased vehicle trips.

Reasonably foreseeable future actions not anticipated to have a net adverse or beneficial effect on the ambient noise environment, other than short-term, localized impacts due to construction activities, include:

·        Infrastructure and transportation projects, such as El Portal Road Improvements Project (Segment D); and Northside-Southside Drive Repaving.

·        Yosemite campground rehabilitation and parking improvements projects, such as Wawona Campground Rehabilitation; and Yosemite Village Interim Parking Improvements.

·        Ecological and trail restoration projects such as Red Peak Pass Trail Rehabilitation and Visitor Use and Floodplain Restoration Program.

·       El Portal Old Wastewater Treatment Facility Removal

Many of the above cumulative projects would result in local, short-term, moderate to major, adverse effects on the ambient noise environment due to construction activities, and in some cases, these effects would occur within the corridor. Over the long term, statewide growth and development would accelerate the national trend in increased air travel, resulting in a local, long-term, minor, adverse effect in some portions of the corridor in wilderness areas due to increased aircraft overflights and associated intrusive noise levels. In nonwilderness areas, cumulative actions that would provide for increased transit use and reduced automobile use or that would reduce vehicle trips in the Valley could result in a local, long-term, minor, beneficial effect within the corridor based on the type of technology that is being implemented for transit purposes, but depending on the extent to which private automobile trips are diverted to transit.

Since Alternative 1 would not involve any substantial construction projects, the local, short-term, moderate to major, adverse cumulative effects on noise due to construction activities that are cited above would be due to the cumulative projects. Over the long term, in wilderness areas, noise impacts in the corridor would be determined almost entirely by cumulative trends in air travel rather than by in-park noise sources under Alternative 1; as discussed above, the national trend in air travel if it continues to increase could result in a local, long-term, minor, adverse effect on the ambient noise environment. In nonwilderness areas, the gradual increase in annual visitation to the park would likely offset the beneficial effects of those cumulative actions that would tend to reduce vehicle trips and their associated noise, resulting in a local, long-term, negligible to minor, adverse effect on noise levels in those portions of the corridor traversed by roadways.

Impairment

Alternative 1 would accommodate a gradual increase in annual visitation (higher use on non-peak days), which could lead to a local, long-term, negligible to minor, adverse effect along the various roads that traverse the corridor in nonwilderness areas. The adverse effect of this alternative on park soundscapes would not be of sufficient magnitude to impair park resources.

Cultural Resources

Archeological Resources

Analysis

The following discussion provides an overview of the types of impacts to archeological resources that could occur within each segment of the Merced River corridor from continued implementation of the park's existing user capacity management program without the VERP program. Effects on archeological resources due to the proposed corridor boundary and zoning in El Portal are also addressed for the El Portal segment.

Impacts in Wilderness. Archeological resource components of the cultural ORV include historic and prehistoric resources related to occupation and homesteading, hunting, travel and trade, the U.S. Cavalry, and wilderness tourism. Due to their remote location and the low level of use occurring in most parts of the Yosemite Wilderness, archeology resources remain largely undisturbed.

User capacity within wilderness areas of Yosemite National Park is addressed through wilderness trailhead quotas and monitoring of wilderness resource conditions under the Wilderness Impact Management System. In Alternative 1, management of the wilderness areas would continue under the existing trailhead quota system and WIMS.

The wilderness trailhead quotas have been in place for decades and do not directly affect archeological resources. Because there is currently unused capacity under the trailhead quota system, some additional demand could be accommodated. The addition of more visitors in the wilderness could have a local, long-term, negligible, adverse impact on archeological resources due to the increased likelihood of visitor-related damage, such as surface collection, vandalism, erosion, and trampling. Overall, archeological resource components of the ORV would be protected and enhanced under this alternative.

Impacts in Yosemite Valley. Archeological resource components of the cultural ORV within Yosemite Valley include several historic and prehistoric sites and districts that relate to homesteading, long-term and seasonal occupation, early tourism, U.S. Cavalry, historic roads and trails, and early park administration.

Visitor capacity in the Valley is not actively managed on a daily basis but is regulated through facility capacities, primarily related to overnight accommodations and parking. Limits on these facilities restrict the number of overnight and day visitors to the Valley. Current management practices sometimes result in significant traffic on peak summer weekends and holidays, as visitors circle through the Valley looking for parking. When park management determines that traffic congestion in the Valley is creating unacceptable human safety and resource impacts, restricted access policies are put into effect to manage traffic.

As park visitation increases through 2020, the limitations on parking and lodging in the Valley under Alternative 1 would restrict the number of visitors that can access the many cultural resources within the Valley. However, since Valley visitation is currently below peak levels reached in the last decade, there may be sufficient capacity to accommodate some increased visitation between now and 2020.

Under Alternative 1, there would be no change to archeological resources in the Valley in the short term. In the long term, there could be local, minor, adverse effects related to increased visitor use and a corresponding increase in the likelihood of visitor-related damage such as vandalism, surface collection, erosion, and trampling.

Impacts in the Gorge. Archeological components of the cultural ORV for the Gorge segment include historic and prehistoric sites related to occupation, the Civilian Conservation Corps, early roads and trails, road development, and early tourism. Many parts of the gorge are inaccessible to visitors.

Under Alternative 1, user capacity would continue to be restricted by the existing level of parking in the Gorge. The current parking capacity would allow for some additional use during the nonpeak season. During peak periods when restricted access is implemented for Yosemite Valley, parking areas in the Gorge become more congested. The existing limits on available parking in the Gorge are expected to limit use levels in this area to the current peak level. Since use levels in the Gorge are relatively low and access is limited by available parking, Alternative 1 is not expected to have any effect on archeological resources for this segment in the long or short term.

Impacts in El Portal. Archeological resources for El Portal consist of some of the oldest prehistoric sites within the Merced River corridor. Prehistoric and historic archeological sites and districts in El Portal include examples of villages, homesteads, early tourism, and the mining, railroad, and timber industries.

The boundary for the El Portal segment of the river in this alternative is based upon the 100-year floodplain or the River Protection Overlay, whichever is greater. The zoning for the El Portal corridor under this alternative calls for park administrative uses (3C zoning) in existing developed areas north and south of the river, and Day Use (2C) zoning for undeveloped areas directly adjacent to the river. Although this zoning might allow for future development of visitor facilities, much of the 2C area is within the River Protection Overlay and is unlikely to be developed.

The area zoned Park Operations and Administration (3C) could allow for the development of facilities or the removal of existing facilities. Most of the facilities currently located in the 3C zones were constructed prior to the river's designation as Wild and Scenic. Much of this area contains archeological resources, and while some of these have been previously disturbed, future development has the potential to adversely affect these resources. If this development or removal occurred and earth-moving activities were required, then intact archeological resource(s), which are identified as an ORV, could be disturbed. This is considered a local, long-term, minor to major, adverse impact, and the intensity of impact would depend on the nature, location, and design of the facility to be developed or removed as well as the quantity and data potential of the archeological resource(s) affected. These actions would be subject to site-specific planning and compliance and would be undertaken in accordance with the stipulations in the park's 1999 Programmatic Agreement and with other elements of the Merced River Plan. Under the Merced River Plan, ORVs must be protected on a segment-wide basis.

The areas zoned Day Use (2C) could allow construction of new facilities and hardened surfaces and the removal or relocation of existing facilities. Development within these management zones also could concentrate human use at specific locations in El Portal, which could affect archeological resources by causing trampling, surface collection, and erosion. However, by providing more structured visitor experiences in the river corridor, use could be directed away from known archeological resources, which would reduce the likelihood of visitor-related damage. If such development or construction occurred and earth-moving activities were required, then intact archeological resource(s), which are identified as an ORV, could be disturbed. This is considered a local, long-term, minor to major, adverse impact, and the intensity of impact would depend on the nature, location, and design of the facility to be developed or removed as well as the quantity and data potential of the archeological resource(s) affected. Like the actions in the 3C zones, these actions would be subject to site-specific planning and compliance and would be undertaken in accordance with the stipulations in the park's 1999 Programmatic Agreement and with other elements of the Merced River Plan. Under the Merced River Plan, ORVs must be protected on a segment-wide basis. Because the river corridor boundary in this alternative would be smaller than under the three action alternatives, fewer archeological resources fall within the river corridor boundary. The absence of a VERP framework in this alternative would not enable the park to monitor the effects of use-related impacts on archeological resources.

User capacity for visitors within El Portal is currently managed via parking capacity in the area. Continuation of the existing user capacity program in the El Portal segment would not change the visitor facilities available on adjacent private lands, the lack of visitor facilities on park lands, or the amount of informal parking available. Because current use does not exceed existing parking capacity, there is potential for an increase in visitor use in El Portal adjacent to the river. This potential increase could have long-term negligible to minor adverse impacts to cultural resources. Additionally, continuation of existing user capacity management policies under the No Action Alternative would not require changes to employee housing, amenities, or other facilities located in El Portal. Park planning efforts and future development in El Portal would continue to be based on the goals of the General Management Plan and on existing utility capacities. Since the General Management Plan calls for increased employee housing in El Portal, it is likely that the level of employee housing would increase in the future, while remaining within utility capacities.

Overall, Alternative 1 is expected to result in long-term, minor to major, adverse effects on archeological resources within the El Portal segment of the river corridor.

Impacts in Wawona. Archeological resources in Wawona include historic and prehistoric sites and districts that relate to homesteading, long-term and seasonal occupation, early tourism, the U.S. Cavalry, historic roads and trails, and early park administration.

Visitor capacity in Wawona is not actively managed but is limited through available overnight lodging and parking areas on park lands. Visitor lodging is also provided on private lands within the river corridor. Continuation of the existing user capacity policies in Wawona could allow for a slight increase in visitor use over the next few decades, which could increase the likelihood of visitor-related damage to archeological resources such as surface collection, vandalism, erosion, and trampling. Therefore, the existing user capacity program in Wawona could result in local, long-term, minor, adverse impacts to archeological resources.

Summary of Alternative 1 Impacts. Compliance with existing park policies, including the 1999 Programmatic Agreement, and federal laws, such as the National Historic Preservation Act, would help ensure that the cultural ORVs in each river segment are being protected and enhanced.

Alternative 1 would continue existing user capacity programs for areas within the Merced River corridor. User capacity is managed through trailhead quotas in wilderness areas and primarily through facility-based capacities in most other areas. Continuation of these existing user capacity programs is not expected to result in any changes to cultural resource ORVs in the short term. In the long term, Alternative 1 is expected to result in a local, long-term, minor, adverse impact to archeological resources due to the increased likelihood of visitor-related damage to these resources and the increased likelihood of development outside of the El Portal river corridor boundary.

Cumulative Impacts

Cumulative effects on archeological resources are based on an analysis of past, present, and reasonably foreseeable future actions in the Yosemite region. The projects identified below include only those projects that could affect archeological resources within the river corridor or in the park vicinity.

Past Actions. Archeological resources are subject to damage from development, vandalism, visitor access, and natural processes such as flooding and wildland fires.

In general, archeological resources within the Merced River corridor are the result of thousands of years of human occupation. Development of facilities within the river corridor has disturbed or destroyed numerous archeological resources and compromised the integrity of numerous other such resources. Park projects from the recent past that have had a minor, adverse effect on historic archeological resources within the river corridor include:

·       Cascades Diversion Dam Removal

Present Actions. Archeological resource sites in the Wilderness, Yosemite Valley, Gorge, El Portal, and Wawona segments of the river corridor are considered to be at risk due to existing facility development. These sites are at or adjacent to trails, structures, utility systems, and other facilities and are subject to ongoing disturbances such as trampling, surface collection, and ground disturbance associated with facility maintenance. Certain specific projects have been mitigated to have no adverse effect, these include:

·       Lower Yosemite Fall Project

·       Cook's Meadow Ecological Restoration

·       South Fork Bridge Replacement

·       Utilities Master Plan/East Yosemite Valley Utilities Improvement Plan

Reasonably Foreseeable Future Actions

The extensive grading and ground disturbance that could be required for the reasonably foreseeable future projects listed below could disturb individual archeological resources. Each of these projects is within an archeologically sensitive area, such as a river valley or a mountain meadow. Specific impacts would depend on the nature, location, and design of the facility to be developed or removed as well as the quantity and data potential of the archeological resource(s) affected. Any disturbance of an individual archeological resource is considered to be a long-term, adverse impact.

·       Curry Village and East Yosemite Valley Campgrounds Improvements

·       El Portal Road Improvements Project (Segment D)

·       Indian Cultural Center

·       Wawona Campground Rehabilitation

·       Yosemite Lodge Area Redevelopment

·       Yosemite Village Interim Parking Improvements

·       El Portal Concept Plan

·       Tuolumne Meadows Concept Plan

·       El Portal Old Wastewater Treatment Facility Removal

Overall, these cumulative actions in combination with Alternative 1 could have a net long-term, moderate, adverse impact on archeological resources with the Merced River corridor.

Impairment

Alternative 1 could result in local, long-term, minor to moderate, adverse effects on archeological resources. These effects are not expected to impair the park's archeological resources for future generations.

National Historic Preservation Act Section 106 Summary

Under regulations of the Advisory Council on Historic Preservation (36 CFR 800.9) that address the criteria of effect and adverse effect, the user capacity program and the El Portal boundary and zoning designations proposed under this alternative would allow (but do not prescribe) actions that have the potential to adversely affect significant properties. The National Park Service has determined that selection of this alternative would result in no adverse effect to historic properties listed in or eligible for listing in the National Register of Historic Places, because the plan does not prescribe specific action. Future actions that are allowed under the proposed alternative would undergo environmental review to determine potential effects on historic properties.

Traditional Cultural Resources

Analysis

The following discussion provides an overview of the types of impacts to traditional cultural resources that could occur within each segment of the Merced River corridor from implementation of the park's user capacity management program without the VERP program. Effects on traditional cultural resources due to the proposed corridor boundary and zoning in El Portal are also addressed for the El Portal segment.

Impacts in Wilderness. Traditional cultural resources in the wilderness include continuing uses such as the travel/trade routes connecting the east and west slopes of the Sierra Nevada range. Existing conditions of these travel/trade routes (which includes the routes themselves and the American Indian's ability to access these routes) are good. User capacity within wilderness areas of Yosemite National Park is currently addressed through trailhead quotas and monitoring of wilderness resource conditions under the Wilderness Impact Management System. In Alternative 1, management of the wilderness areas would continue under the existing trailhead quota system and WIMS.

The wilderness trailhead quotas have been in place for decades and do not directly affect traditional cultural resources. Because there is currently unused capacity under the trailhead quota system, some additional demand could be accommodated. The addition of more visitors in the wilderness could have a local, long-term, minor, adverse impact on traditional cultural resources due to the increased likelihood of visitor-related damage to the trails and an increased likelihood for encounters with other visitors.

Impacts in Yosemite Valley. Traditional cultural resources in Yosemite Valley encompass many natural and cultural features throughout the Valley that are traditionally valued by local American Indian groups, including gathering areas, religious sites, village sites, and cemeteries.

Currently some of these areas are experiencing moderate adverse effects from concentrated visitor-use such as trampling and erosion. Other traditional cultural resources are actively being managed through the use of prescribed fire and invasive plant removal by the National Park Service (NPS 1997p). Under Alternative 1 there would be no change to traditional cultural resources in the Valley in the short term. In the long term, there could be local, minor, adverse effects related to increased visitor use and a corresponding increase in the likelihood of visitor-related damage, such as vandalism, erosion, and trampling.

Impacts in the Gorge. Traditional cultural resources in the Gorge segment include gathering areas and villages. Traditional cultural resources in the gorge are actively being managed through the use of prescribed fire and invasive plant removal by the National Park Service (NPS 1997p). Under Alternative 1, user capacity would continue to be restricted by the existing level of parking in the Gorge. Use levels in the Gorge are generally relatively low, as access is limited by available parking and topography. For example, during peak periods when restricted access is implemented for Yosemite Valley, parking areas in the Gorge become more congested. The existing limits on available parking in the Gorge are expected to limit use levels in this area to the current peak level. This parking capacity would allow for some additional use during the non-peak season. These use levels could increase in the nonpeak season, which could have both short term and long term, minor, adverse effects on traditional cultural resources for the segment under Alternative 1.

Impacts in El Portal. Traditional cultural resources in El Portal consist of, but are not limited to, gathering areas, cemeteries, geological features of traditional spiritual importance, and prehistoric and historic village sites. Like Yosemite Valley, contemporary associated tribes consider all of El Portal to be a traditional use area.

Currently, some of these areas are experiencing adverse effects from concentrated human-use due to roads, housing, parking, and other amenities located in proximity to El Portal's traditional cultural resources. These effects include trampling and erosion. Other traditional cultural resources are actively being managed through the use of prescribed fire and invasive plant removal by the National Park Service (NPS 1997p).

The boundary for the El Portal segment of the river in this alternative is based on the 100-year floodplain or the River Protection Overlay, whichever is greater. The zoning proposed for the El Portal corridor under Alternative 1 calls for Park Operations and Administration (3C) in existing developed areas north and south of the river, and Day Use (2C) for undeveloped areas directly adjacent to the river. Although this zoning plan might allow for future development of visitor facilities, much of the 2C zone is within the River Protection Overlay and is unlikely to be developed. The areas zoned 3C south and north of the river have the potential to be developed as administrative facilities. If development occurs in these zones, there is a potential to adversely affect traditional cultural resources. However, no new development would occur inside the corridor without further site-specific planning and compliance that would be undertaken in accordance with the stipulations in the park's 1999 Programmatic Agreement and the existing elements of the Merced River Plan. The adverse effects of new development would likely be local, long term, and negligible to moderate.

User capacity for visitors within El Portal is currently managed via parking capacity in the area. Continuation of the existing user capacity program in the El Portal segment would not change the visitor facilities available on adjacent private lands, the lack of visitor facilities on park lands, or the amount of informal parking available. Additionally, continuation of user capacity management policies under the No Action Alternative would not require changes to employee housing in El Portal, amenities, or other facilities located there. Park planning efforts and future development in El Portal would continue to be based on the General Management Plan and on existing utility capacities. Since the General Management Plan calls for increased employee housing in El Portal, it is likely that the level of employee housing would increase in the future, while remaining within utility capacities. Therefore, continued implementation of the existing user capacity program is not expected to result in any changes to traditional cultural resources in El Portal.

Overall, Alternative 1 is expected to result in long-term, negligible to moderate, adverse effects on traditional cultural resources within the El Portal segment of the river corridor.

Impacts in Wawona. Traditional cultural resources in Wawona include, but are not limited to, gathering areas, cemeteries, and village sites. Currently, some of these areas are experiencing adverse effects of concentrated visitor-use such as trampling and erosion. Other traditional cultural resources are actively being managed through the use of prescribed fire and invasive plant removal by the National Park Service (NPS 1997p).

Visitor capacity in Wawona is not directly managed but is limited through available overnight lodging, camping, and parking areas on park lands. Visitor lodging is also provided on private lands within the river corridor. Continuation of the existing user capacity policies in Wawona could allow for a slight increase in visitor use over the next few decades, which could increase the likelihood of visitor-related damage to traditional cultural resources such as vandalism, erosion, and trampling. The lack of a VERP program would not enable the National Park Service to detect these effects and take management actions. Therefore, the existing user capacity program in Wawona is not expected to have new, short term impacts but could result in local, long-term, minor, adverse impacts to traditional cultural resources.

Summary of Alternative 1 Impacts. Compliance with existing park policies, including the 1999 Programmatic Agreement; the 1997 Agreement between the National Park Service, Yosemite National Park, and the American Indian Council of Mariposa County, Inc. for Conducting Traditional Activities; and federal regulations such as the National Historic Preservation Act, American Indian Religious Freedom Act, and Native American Graves Protection and Repatriation Act would help ensure that the cultural ORVs in each river segment are being protected and enhanced.

Alternative 1 would continue existing user capacity programs for areas within the Merced River corridor. User capacity is managed through trailhead quotas in wilderness areas and primarily through facility-based capacities in most other areas. Continuation of these existing user capacity programs is not expected to result in any changes to traditional cultural resources in the short term. In the long term, Alternative 1 is expected to result a local, long-term, minor, adverse impact to traditional cultural resources due to the increased likelihood of visitor-related damage to these resources and the increased likelihood of development outside of the El Portal river corridor boundary.

Cumulative Impacts

Cumulative effects on traditional cultural resources are based on analysis of past, present, and reasonably foreseeable future actions in the Yosemite region. The projects identified below include only those projects that could affect traditional cultural resources within the river corridor or in the park vicinity.

Past Actions. Traditional cultural resources have been lost or damaged in Yosemite National Park through past development, visitor use, natural events, and widespread disruption of cultural traditions. Nevertheless, Yosemite retains many sites and resources of significance to local and culturally associated American Indians.

In general, traditional cultural resources within the Merced River corridor are the result of thousands of years of human occupation. Development of facilities within the river corridor has disturbed or destroyed numerous traditional cultural resources and compromised the integrity of numerous other such resources.

The Cascades Diversion Dam Removal project is a recent park project that benefited traditional cultural resources within the river corridor by restoring the river and its banks back to a more natural state and allowing native vegetation to repopulate the banks.

The Yosemite Valley Plan, completed in 2000, calls for projects that will have both adverse and beneficial effects on traditional cultural resources by damaging gathering areas and historic villages or restricting access to traditional use places, and by beneficially affecting traditional cultural resources by restoring native plant habitat.

Present Actions. Projects currently underway that will improve traditional cultural resources in the long term include the Cook's Meadow Ecological Restoration, Parkwide Invasive Plant Management Plan. These two projects benefit native plant communities through restoration, improved site development, or ecosystem planning. Traditional gathering areas are positively affected in the long term by these projects.

The Lower Yosemite Fall Project and the South Fork Merced River Bridge Replacement adversely affect traditional cultural resources in the short term during construction. The Lower Yosemite Fall Project site design will continue to adversely affect traditional cultural properties in the long term. Potential adverse affects from the Utilities Master Plan/East Yosemite Valley Utilities Improvement Plan on traditional cultural resources are being mitigated by salvaging and reusing sod, resulting in no permanent damage.

Reasonably Foreseeable Future Actions. Reasonably foreseeable future actions proposed in the region are separated below into three general categories: (1) projects that could adversely affect traditional cultural resources; (2) projects that could beneficially affect traditional cultural resources; and (3) projects that could either adversely or beneficially affect traditional cultural resources. Examples of projects that could have a cumulative, adverse effect on traditional cultural resources include:

·       Curry Village and East Yosemite Valley Campgrounds Improvements

·       Wawona Campground Rehabilitation

·       El Portal Road Improvements Project (Segment D)

These three projects could adversely affect traditional cultural resources by damaging gathering areas and historic villages or restricting access to traditional use places. These projects could have long-term, adverse impacts on traditional cultural resources. The intensity of this impact would depend on the extent to which gathering sites were damaged and access to traditional use places was restricted.

Examples of projects that could have a cumulative, beneficial effect on traditional cultural resources include:

·       Yosemite Lodge Area Redevelopment

·       Indian Cultural Center

·       Visitor Use and Floodplain Restoration Program

·       El Portal Old Wastewater Treatment Facility Removal

The removal of the wastewater treatment facility at El Portal would benefit traditional cultural resources by restoring the area to a more natural state. The Yosemite Lodge project could benefit traditional cultural resources through sensitive site design. The Indian Cultural Center will provide a place and facilities for the local American Indian community to assemble in their ancestral land (Yosemite Valley).

Examples of projects that could have adverse and beneficial effects on traditional cultural resources include:

·       El Portal Concept Plan

·       Tuolumne Meadows Concept Plan

The El Portal Concept Plan and the Tuolumne Meadows Concept Plan could adversely affect traditional cultural resources by damaging gathering areas and historic villages or restricting access to traditional use places, and could beneficially affect traditional cultural resources by restoring native plant habitat.

The cumulative projects within and in the vicinity of Yosemite National Park would result in a long-term, minor, beneficial impact on traditional cultural resources because the long-term, beneficial impacts associated with the management of natural resources and river processes in the vicinity of the Merced River corridor would be partially offset by the short- and long-term, adverse impacts associated with damaging gathering areas or restricting access to traditional use places.

Overall, these cumulative actions in combination with Alternative 1 could have a net long-term, minor, beneficial impact on traditional cultural resources within the Merced River corridor. They could also result in a long-term, minor, adverse impact due to increased development and visitor-related damage.

Impairment

Alternative 1 could result in local, long-term, minor, adverse effects on traditional cultural resources. Therefore, this alternative is not expected to impair the park's traditional cultural resources for future generations.

National Historic Preservation Act Section 106 Summary

Under regulations of the Advisory Council on Historic Preservation (36 CFR 800.9) that address the criteria of effect and adverse effect, the user capacity program and the El Portal boundary and zoning designations proposed under this alternative would allow (but do not prescribe) actions that have the potential to adversely affect significant properties. The National Park Service has determined that selection of this alternative would result in no adverse effect to historic properties listed in or eligible for listing in the National Register of Historic Places, because the plan does not prescribe specific action. Future actions that are allowed under the proposed alternative would undergo environmental review to determine potential effects on historic properties.

Historic Sites, Structures, and Landscapes

Analysis

The following discussion provides an overview of the types of impacts to historical sites, structures, and landscapes that could occur within each segment of the Merced River corridor from implementation of the park's user capacity management program without the VERP program. Effects on these resources due to the proposed corridor boundary and zoning in El Portal are also addressed for the El Portal segment.

Impacts in Wilderness. Historic sites, structures, and landscapes in the wilderness include the Merced Lake High Sierra Camp, John Muir trail, remains of the original Yosemite Grant boundary fence, U.S. Cavalry trails, and sites associated with early stock grazing.

User capacity within wilderness areas of Yosemite National Park is addressed through trailhead quotas and monitoring of wilderness resource conditions under the Wilderness Impact Management System. In Alternative 1, management of the wilderness areas would continue under the existing trailhead quota system and WIMS.

The wilderness trailhead quotas have been in place for decades, and do not directly affect historic sites, structures, and landscapes. Because there is unused capacity under the trailhead quota system, some additional demand can be accommodated. The addition of more visitors in the wilderness could have a local, long-term, minor, adverse impact on historic sites, structures, and landscapes due to the increased likelihood of visitor-related damage such as surface collection, vandalism, erosion, and trampling.

Impacts in Yosemite Valley. Historic sites, structures, and landscapes in Yosemite Valley include the Yosemite Valley Historic District, which consists of historic bridges, a campground, orchards, trails, roads, residences, administrative facilities, and visitor accommodations. This district includes the Yosemite Village Historic District and the Curry Village Historic District. The Valley also contains several National Register-eligible or -nominated historic buildings and three National Historic Landmarks: the LeConte Memorial Lodge, the Ranger's Club, and The Ahwahnee.

Under Alternative 1, there would be no change to historic sites, structures, and landscapes in the Valley in the short term because visitor use levels would remain similar to current levels. In the long term, there could be local, minor, adverse effects related to increased visitor use and a corresponding increase in visitor-related damage, such as vandalism, surface collection, erosion, and trampling.

Impacts in the Gorge. Historic sites, structures, and landscapes in the Gorge segment include the Merced Canyon Travel Corridor and the powerhouse associated with the Yosemite Valley Hydroelectric Power Plant.

Under Alternative 1, user capacity would continue to be restricted by the existing level of parking in the Gorge. The current parking capacity would allow for some additional use during the nonpeak season. During peak periods when restricted access is implemented for Yosemite Valley, parking areas in the Gorge become more congested. The existing limits on available parking in the Gorge are expected to limit use levels of this area to the current peak level. Since use levels in the Gorge are relatively low and access is limited by available parking, Alternative 1 is not expected to have any effect on historic resources for the segment in the long or short term.

Impacts in El Portal. Historic sites, structures, and landscapes in the El Portal segment consist of the Old El Portal cultural landscape, the Murchison (National Lead Company) structures, railroad houses, the chapel, the old store, the El Portal Market, the old hotel (Yosemite Institute administrative offices), Bagby Station, and other sites and structures related to early industry, homesteading, and tourism in the Merced River corridor. Some of these structures are privately owned or used only as National Park Service or park partner's administrative facilities. Because these structures are not open to the public, they are unlikely to experience adverse effects from visitor use.

The boundary for the El Portal segment of the river in this alternative is based on the 100-year floodplain or the River Protection Overlay, whichever is greater. The zoning proposed for the El Portal corridor under Alternative 1 calls for primarily Park Operations and Administration (3C) in existing developed areas north and south of the river, and primarily Day Use (2C) for undeveloped areas directly adjacent to the river. Although this zoning designation might allow for future development of visitor facilities, much of the 2C is within the River Protection Overlay and is unlikely to be developed. The areas zoned 3C south and north of the river have the potential to be developed as administrative facilities. These areas contain historic sites, structures, and/or landscapes and, if developed further, have the potential to adversely affect these resources. The potential actions would be subject to site-specific planning and compliance and would be undertaken in accordance with the stipulations in the park's 1999 Programmatic Agreement. Therefore the adverse effects of new development would likely be local, long term, and minor to moderate.

Because the boundary in Alternative 1 is smaller than under the three action alternatives, fewer historic sites, structures, and landscapes fall within the river corridor boundary. Although all ORVs are protected regardless of whether they fall within or outside of the boundary, the resources within the boundary would likely receive greater protection due to the stringent requirements of the existing Merced River Plan elements and the Wild and Scenic Rivers Act. The smaller boundary in Alternative 1 could result in a local, long-term, minor to moderate, adverse effect to historic sites, structures, and landscapes.

User capacity within El Portal is currently managed via parking capacity in the area. Continuation of the existing user capacity program in the El Portal segment would not change the visitor facilities available on adjacent private lands, the lack of visitor facilities on park lands, or the amount of informal parking available. Therefore, the existing user capacity program is not expected to result in any changes to historic resources in El Portal.

Alternative 1 would allow for an increase in employee housing in El Portal, which could substantially increase the population of El Portal and require new development within the El Portal Cultural Landscape. This new development will comply with the proposed El Portal design guidelines, and any treatment of the cultural landscape would be subject to site-specific planning and compliance and undertaken in accordance with the stipulations in the park's 1999 Programmatic Agreement. The adverse effects of new development would likely be local, long term, and minor to moderate.

Overall, Alternative 1 is expected to result in long-term, minor to moderate, adverse effects on historic resources within the El Portal segment of the river corridor.

Impacts in Wawona. Historic sites, structures, and landscapes in Wawona include the Washburn cultural landscape, the Chowchilla Mountain Road, Civilian Conservation Corps structures, the Wawona Covered Bridge, the Wawona Hotel (a National Historic Landmark), and the Pioneer Yosemite History Center. Many relocated and individually listed National Register historic structures comprise the Pioneer Yosemite History Center.

Visitor capacity in Wawona is not actively managed but is limited through available overnight lodging and parking areas on park lands. Visitor lodging is also provided on private lands within the river corridor. Continuation of the existing user capacity policies in Wawona could allow for a slight increase in visitor use over the next few decades, which could increase the likelihood of visitor-related damage to historic sites, structures, and landscapes such as vandalism, erosion, and trampling. Therefore, the existing user capacity program in Wawona could result in local, long-term, minor, adverse impacts to these resources.

Summary of Alternative 1 Impacts. Compliance with existing park policies, including the 1999 Programmatic Agreement, Yosemite National Park Design Guidelines, and federal regulations such as the National Historic Preservation Act, would help ensure that the cultural ORVs in each river segment are being protected and enhanced.

Alternative 1 would continue existing user capacity programs for areas within the Merced River corridor. User capacity is managed through trailhead quotas in wilderness areas and primarily through facility-based capacities in most other areas. Continuation of the existing user capacity programs is not expected to result in any changes to historic resources in the short term. In the long term, Alternative 1 is expected to result a local, minor, adverse impact to some historic sites, structures, and landscapes due to increased likelihood of visitor-related damage to these resources and the increased likelihood of development outside of the El Portal river boundary. Other historic resources in El Portal are no affected by visitor use. These include the Murchison structures, the Yosemite Institute administrative offices, Bagby Station, the El Portal railroad houses, the El Portal chapel, and the old store in El Portal.

Cumulative Impacts

Cumulative effects on cultural resources as they relate to historic sites, structures, and landscapes are based on analysis of past, present, and reasonably foreseeable future actions in the Yosemite region. The projects identified below include only those projects that could affect historic sites, structures, and landscapes within the river corridor or in the park vicinity.

Past Actions. Past development, visitor use, and natural events have destroyed or damaged historic sites, structures, and landscapes. In wilderness areas, historical landscape resources include remnants of early stock grazing, trails, and work camps. In Yosemite Valley, Wawona, and El Portal, cultural landscape resources include early hotels, bridges, stores, studios, cabins, farms, and railroad structures that were associated with early Euro-American pioneer settlement and industries. In the Merced River gorge, cultural landscape resources include segments of the early wagon road and engineering projects. Rapidly disappearing structures and sites in other areas include homestead cabins, barns, road and trail segments, bridges, mining complexes, railroad and logging facilities, blazes, and campsites. These resources are reminders of the area's ranching, grazing, lumbering, and mining history.

Past park projects that adversely affected historic sites, structures, and landscapes within the river corridor include:

·       Cascades Diversion Dam Removal

·       Cascades Housing Removal

Both of these river restoration projects required removal of historic structures that were contributing elements to the Yosemite Valley Hydroelectric System, a National Register-nominated property. The removal of these structures resulted in long-term, moderate, adverse impacts.

Every year, the park's historic preservation crew restores or rehabilitates historic structures throughout the front country and wilderness, beneficially affecting these resources in the long term. Most recently, the crew completed the restoration of the covered bridge in Wawona.

The implementation of projects outlined in the Yosemite Valley Plan may have adverse and beneficial impacts on historic sites, structures, and landscapes. The plan prescribed the removal or benign neglect of some resources, resulting in a long-term, moderate, adverse effect. The plan may require removal of historic orchards and bridges that could be eligible for listing on the National Register or as contributing elements to a National Register historic district. Additionally, these plans could add noncontributing elements to historic landscapes. Conversely, the plan also prescribed management actions to treat historic sites, structures, and landscapes.

Present Actions. Projects currently underway that adversely affect historic sites, structures, or landscapes include the Cook's Meadow Ecological Restoration, which necessitated the removal of a historic road, and the Lower Yosemite Fall Project, which benefited the Yosemite Valley historic landscape through improved site design that complements existing significant historic landscape characteristics.

Reasonably Foreseeable Future Actions. Reasonably foreseeable future actions proposed in the region are separated below into two general categories: (1) projects anticipated to have a net adverse effect; and (2) projects anticipated to have adverse and beneficial effects to historic sites, structures, and landscapes.

Projects anticipated to have a net adverse effect include:

·       Yosemite Village Interim Parking Improvements

·       El Portal Road Improvements Project (Segment D)

·       Indian Cultural Center

·       Wawona Campground Rehabilitation

·       Environmental Education Campus Development Program

These projects require new development that will likely have a negligible to minor impact on historic sites, structures, or landscapes within Yosemite Valley. Yosemite Village Interim Parking Improvements will alter historically significant circulation routes, the El Portal Road Improvements Project will possibly alter dimensions or materials of this historic road, and the Indian Cultural Center will add structures to a currently undeveloped portion of the Yosemite Valley Historic District. The Environmental Education Campus Development Program will require the redevelopment of historic structures and landscapes.

Projects anticipated to have adverse and beneficial effects include:

·       El Portal Concept Plan

·       Tuolumne Meadows Concept Plan

·       The Tuolumne River Wild and Scenic River Comprehensive Management Plan

Each of these plans could prescribe removal or benign neglect of historic sites, structures, and landscapes, resulting in a long-term, moderate, adverse effect. Additionally these plans could add noncontributing elements to historic landscapes.

Conversely, each of these plans could prescribe management actions to protect historic sites, structures, and landscapes, resulting in a local, long-term, moderate, beneficial impact. The overall impact intensity of any planning project would depend on the extent to which the plan's recommendations were implemented.

The cumulative projects would have a long-term, moderate, adverse impact on historic sites, structures, and landscapes because these projects would, individually and in combination, disrupt historical circulation and land use patterns, add noncontributing elements to the cultural landscape, or result in the removal of historic fabric or resources. The intensity of the overall impact would depend on the degree of the impacts associated with the individual projects that would affect cultural landscape resources.

Overall, these cumulative actions in combination with Alternative 1 could have a net long-term, moderate, adverse impact on historic sites, structures, and landscapes within the Merced River corridor.

Impairment

Impacts associated with Alternative 1 are not expected to impair the park's historic sites, structures, and landscapes for future generations.

National Historic Preservation Act Section 106 Summary

Under the 1999 Programmatic Agreement and the regulations of the Advisory Council on Historic Preservation (36 CFR 800.9) that address the criteria of effect and adverse effect, the user capacity program and the El Portal boundary and zoning designations proposed under this alternative would allow (but do not prescribe) actions that have the potential to adversely affect significant properties. The National Park Service has determined that selection of this alternative would result in no adverse effect to historic properties listed in or eligible for listing in the National Register of Historic Places.

Visitor Experience

Analysis

The following discussion provides an overview of the types of impacts to recreation, interpretation and orientation, visitor services, and wilderness experience that could occur within each segment of the Merced River corridor under the No Action Alternative. Effects on visitor experience from the proposed corridor boundary and zoning in El Portal are also addressed in the El Portal segment discussion.

Recreation

Analysis

The following discussion provides an overview of the types of impacts to recreational resources and the recreation ORVs that could occur within each segment of the Merced River corridor from implementation of existing user capacity policies. Effects on recreation from the proposed corridor boundaries and zoning in El Portal are also addressed for the El Portal segment.

Impacts in Wilderness. Recreation ORVs in the Wilderness segment include outstanding opportunities for solitude along the river, primitive and unconfined recreation, and recreational opportunities such as day hiking, backpacking, horseback riding and packing, camping, and the enjoyment of natural river sounds.

User capacity within wilderness areas of Yosemite National Park is currently addressed primarily through trailhead quotas for overnight visitors, monitoring of wilderness resource conditions under the Wilderness Impacts Monitoring System, and management zoning of the Wilderness areas, which calls for very low levels of facility development and visitor use in wilderness areas. There are currently no restrictions on day use within wilderness areas. Because most Wilderness trails receive relatively low levels of use, and because day use by hikers causes few impacts, quotas have not been needed. Under Alternative 1, wilderness areas would continue to be managed in this manner.

The existing wilderness trailhead quotas have been in place for decades, and in general seem to provide sufficient access for people desiring overnight wilderness access, while providing for the solitude desired from a wilderness experience and protection of natural, cultural, and wilderness resources. Although park visitation is expected to increase through 2020 under Alternative 1, there is currently some unused capacity within the Wilderness Trailhead Quota System. Wilderness overnight visitation numbers are down from the levels of the 1980s, but use has begun increasing again in recent years. Thus, most visitors who want to access the Wilderness can, although they may not be able to obtain a permit for their preferred destination.

Under Alternative 1, numbers of day visitors in wilderness areas would be expected to continue to increase in areas accessible from the Valley, such as Little Yosemite Valley. The increase in use in these areas could result in local, long-term, minor to moderate, adverse effects on recreation and the recreation ORVs, due to decreased opportunities for solitude.

Alternative 1 is not expected to result in any substantive change in access to day use or overnight recreation opportunities in wilderness areas. Alternative 1 would be expected to have a local, long-term, minor to moderate, adverse effect on recreation and the recreation ORVs in those areas affected by day visitors. Otherwise, Alternative 1 would not affect recreation in wilderness areas and the spectrum of recreational opportunities encompassed in the recreation ORV would continue to be protected and enhanced.

Impacts in Yosemite Valley. The recreation ORVs in Yosemite Valley include opportunities to experience a spectrum of river-related recreational activities, from nature study and sightseeing to hiking.

Visitor capacity in the Valley is not actively managed on a daily basis, but is regulated through facility capacities (primarily related to overnight accommodations, parking, and utilities), management zoning (which provides guidance on facility development and visitor use levels), and other use limits implemented through the Superintendent's Compendium or other policies. These existing policies, particularly the limits on overnight use and facilities, indirectly limit the number of visitors to the Valley. Current management practices sometimes result in significant traffic on peak summer weekends and holidays, as visitors circle through the Valley looking for parking. Park management sometimes implements restricted access policies to manage traffic into Yosemite Valley. These are implemented when traffic congestion is creating unacceptable human safety and resource impacts. Visitor surveys over the years have indicated that traffic congestion and parking are two of the main factors that adversely affect visitor experience in the Valley (Gramann 1992; ORCA 2000; Manning et al. 1999a, b).

In the short term, the continuation of existing policies under the No Action Alternative would not be expected to affect visitor access to recreational opportunities. As park visitation increases through 2020, the limitations on parking and lodging in the Valley would limit the number of visitors who can access the many recreation activities within the Valley during peak periods. In the long term, assuming no increase in overnight accommodations or day-visitor parking in the Valley, there would likely be more days when potential day visitors could not find parking in the Valley, were subject to restricted access controls in trying to reach the Valley, or perceived adverse effects to their experience related to traffic congestion and crowding. These adverse effects would likely occur only during peak periods, reducing the overall effect on recreation to a local, long-term, minor to moderate, adverse effect.

Impacts in the Gorge. The recreation ORVs for the Gorge segment of the river corridor are related to the opportunities for a spectrum of recreational opportunities, such as picnicking, fishing, photography, and sightseeing. Access to the gorge is limited by available parking along Highway 140 and at two off-road parking areas. User capacity for the gorge is currently managed through parking access.

Under Alternative 1, user capacity would continue to be limited primarily through the existing level of parking in the gorge. It is likely that the existing parking capacity would allow for some additional use during non-peak seasons. During peak periods and when restricted access is implemented for Yosemite Valley, parking areas in the gorge become more congested. The existing limits on available parking in the gorge would be expected to limit peak uses of this area to the current peak level of use. Increased visitation could result in reaching this peak on more days, but would likely be limited to peak periods. Since use levels in the gorge are relatively low and access is limited by available parking, the overall effect of Alternative 1 on access to recreation activities in the gorge, the quality of recreation experiences, and the recreation ORVs in the long term is expected to be local, negligible to minor, and adverse.

Impacts in El Portal. The recreation ORVs for El Portal are related to a range of river-related activities, and in particular whitewater rafting and kayaking. In addition, fishing is noted in the ORVs and this segment of the Merced River is the only segment classified as a Wild Trout Fishery. There are no established visitor facilities on National Park Service lands in this segment, although commercial rafting operations use an existing raft launch at the western edge of the segment and there are many informal parking areas along Highway 140.

The boundary for the El Portal segment of the river in Alternative 1 is based upon the 100-year floodplain or the River Protection Overlay, whichever is greater. The management zoning for the El Portal corridor under Alternative 1 calls for park administrative uses (3C) in existing developed areas north and south of the river, and day use (2C) for undeveloped areas directly adjacent to the river. This narrow boundary would allow for some additional development outside the river corridor boundary. Within the corridor, the areas zoned 3C have the potential to be developed as administrative facilities, but only if these facilities can meet the Merced River Plan criteria for construction within the river corridor (protection of the ORVs). The areas zoned for day use would also allow for some future development of visitor facilities inside the corridor; however, much of the area zoned 2C is within the River Protection Overlay and is unlikely to be developed. Development of additional administrative facilities north of the river would not adversely affect the access to or opportunities for recreation activities, since these potential development areas are not currently used for recreation access. Since there are no existing visitor facilities on National Park Service lands, visitor use within the corridor is limited, and most of the recreation in this area is concentrated in and near the river, the proposed boundary and management zoning would likely have a long-term, local, negligible, adverse effect on access to recreation, the quality of the visitor experience, and the recreation ORVs within this segment.

Visitor capacity within El Portal is currently managed primarily by the parking capacity, the lack of visitor facilities on National Park Service lands, and existing agreements with the Bureau of Land Management on commercial rafting operations. Continuation of the existing user capacity program in the El Portal segment would not change the visitor facilities available on adjacent private lands, the lack of existing visitor facilities on park lands, the amount of parking available, or the access to the spectrum of recreational opportunities included in the recreation ORVs. Therefore, the user capacity program for Alternative 1 would not be expected to result in any short-term or long-term effect on recreation. .

Impacts in Wawona. The recreation ORVs for Wawona relate to the spectrum of river-related recreational activities available, from nature study to photography to hiking. Below Wawona, the recreation ORVs are related to outstanding opportunities for river-related solitude, enjoyment of natural river sounds, and primitive and unconfined recreation in an untrailed, undisturbed environment. River-related recreational opportunities within this area include hiking, fishing, and whitewater kayaking. There is no recreation ORV for the Wawona Impoundment segment.

Visitor capacity in Wawona is not actively managed on a daily basis, but is limited through the availability of overnight lodging and day-visitor parking areas on National Park Service lands. Demand for day-visitor parking currently exceeds the supply on peak summer days, resulting in traffic congestion. Continuation of the current user capacity policies in Wawona would not result in any changes in the short term. If visitation increases in the long term, parking demand could exceed supply on more days. The spectrum of recreational opportunities would be maintained under this alternative, but visitors unable to find parking would not be able to access the recreational opportunities on those peak days. Therefore, the effects of Alternative 1 on access to recreation activities, the quality of the visitor experience, and the recreation ORVs in Wawona would be expected to be a local, long-term, minor, adverse effect.

Summary of Alternative 1 Impacts. Alternative 1 would continue existing user capacity programs for areas within the Merced River corridor. User capacity would continue to be managed through trailhead quotas in wilderness areas, and primarily through facility-based capacities in most other areas. Continuation of these existing user capacity programs would not be expected to result in any changes to recreational access, the quality of the visitor experience, or the recreation ORVs in the short term. In the long term, Alternative 1 could result in local, long-term, minor to moderate, adverse effects on access to recreational activities, the quality of visitor experience, and recreation ORVs in the developed areas of the river corridor, primarily related to traffic congestion and access to parking. The spectrum of recreational opportunities would be maintained under this alternative, but visitors unable to find parking would not be able to access the recreational opportunities on those peak days. Therefore, Alternative 1 would be expected to protect and enhance the recreation ORVs for each segment of the river.

Cumulative Impacts

Cumulative impacts on visitor experience as it relates to recreation are based on analysis of past, present, and reasonably foreseeable future actions in the Yosemite region in combination with potential effects of this alternative. The projects identified include only those that could affect visitor experience within the river corridor or in the park.

Past Actions. Past actions have had both beneficial and adverse effects on recreation. The El Portal Road Improvements Project, Segments A, B and C, had a short-term, adverse effect on visitor access during construction, including delays and closure of the area to recreational use. The project had long-term beneficial effects related to improved access to recreational opportunities along the river corridor and the El Portal Road, and easier, more dependable, and safer access for recreational vehicles, buses, and other vehicles to Yosemite Valley and other park destinations. Overall, this project provided increased access for visitors to the park and expanded recreational opportunities in the vicinity of the park, resulting in a beneficial effect. The Rehabilitate Yosemite Valley Campground Restrooms project had a beneficial effect by improving the quality of visitor facilities in Yosemite Valley.

Projects implemented under the Yosemite Valley Plan could alternately enhance or degrade the quality of the visitor experience in Yosemite Valley. The plan prescribed projects that result in short-term construction effects on access to recreation opportunities, the removal of some existing recreational facilities, and potential limitations on the ability to access Valley destinations by private vehicles. The plan also provides for improvements to the natural environment, reductions in traffic congestion and crowding, and improved visitor facilities in the long term.

Present Actions. Current projects underway include Happy Isles to Vernal Fall Trail Reconstruction, Lower Yosemite Fall Project, Yosemite Motels Expansion, and Yosemite Valley Shuttle Bus Stop Improvements. These projects could result in short-term adverse effects on visitor access to recreation opportunities during construction activities. In the long term, these projects would be expected to have local, beneficial effects on recreation by providing new or improved trails, increasing overnight lodging close to recreation opportunities, and by providing for improved shuttle bus stops for visitors to Yosemite Valley.

Reasonably Foreseeable Future Actions. Reasonably foreseeable future actions proposed in the region are separated below into two general categories: (1) projects anticipated to have a net beneficial effect and (2) projects anticipated to have both adverse and beneficial effects.

Examples of future projects that could have a net, beneficial effect on regional visitor experience as it relates to recreation include:

·       Curry Village and East Yosemite Valley Campgrounds Improvements

·       Multi-Use Trail to West Yosemite Valley

·       Red Peak Pass Trail Rehabilitation

·       Wawona Campground Rehabilitation

·       Yosemite Lodge Area Redevelopment

These projects would improve existing recreation facilities or develop new recreation facilities, increasing recreation opportunities and the quality of the visitor experience.

Reasonably foreseeable future projects that could have both adverse and beneficial impacts include:

·       Update to the Yosemite Wilderness Management Plan

·       El Portal Road Improvements Project (Segment D)

·       Yosemite Village Interim Parking Improvements

These projects have the potential to enhance the quality of the visitor experience in the Wilderness and Yosemite Valley, but could also result in short-term construction effects on access to recreation opportunities and the removal of some existing recreational facilities. For example, the update to the Yosemite Wilderness Management Plan could call for additional restrictions on facilities and activities in wilderness areas. This change could be considered a local, long-term, adverse impact to some users, due to the potential restrictions. This action could also result in a beneficial effect for other user groups whose access to the wilderness would not be affected, but who would benefit from a reduction in facilities and activities and their associated impacts in wilderness areas, and improvements in opportunities for solitude and a primitive and unconfined recreational experience. El Portal Road Improvements Project (Segment D) and the Yosemite Village Interim Parking Improvements would improve traffic circulation and parking in Yosemite Valley, improving visitor access to recreation opportunities.

The past, present, and foreseeable future projects would have a long-term, negligible to minor, beneficial impact, because the beneficial impacts associated with increased visitor access and expanded recreational opportunities would be partially offset by the adverse impacts associated with construction activities and the potential removal of specific recreational opportunities.

Overall, Alternative 1 and the cumulative projects within and in the vicinity of Yosemite National Park would result in a local, long-term, negligible, beneficial cumulative impact on recreation, because an increase in visitor access and an expansion of recreational opportunities would be partially offset by the removal of specific recreational opportunities, and increased congestion in developed areas of the river corridor.

Interpretation and Orientation

Analysis

The following discussion provides an overview of the impacts to interpretation and orientation that could occur within each segment of the Merced River corridor under Alternative 1. Effects on interpretation and orientation from the proposed corridor boundaries and zoning in El Portal are also addressed for the El Portal segment.

Impacts in Wilderness. Under Alternative 1, user capacity in wilderness areas would continue to be managed under the existing Wilderness Trailhead Quota System, and other relevant park policies. This would not be expected to result in any effect on the existing level of interpretive programs in the Wilderness, such as ranger talks at Little Yosemite Valley Backpackers Campground or ranger-led loop hikes.

Impacts in Yosemite Valley. Under Alternative 1, user capacity in Yosemite Valley would continue to be managed primarily through limitations on overnight and day-use parking facilities, as well as other relevant park policies. Continuation of the existing user capacity program in Yosemite Valley would not be expected to affect the availability and diversity of interpretation, orientation, education, and information services within the corridor.

Impacts in the Gorge. No interpretive programs are currently offered in the Gorge segment. Alternative 1 would have no impact on interpretation and orientation for the gorge.

Impacts in El Portal. Under Alternative 1, the proposed corridor boundary and management zoning reflect the El Portal segment's current and planned use as primarily an administrative center. The proposed corridor boundary, zoning configuration, and user capacity programs would not impact existing interpretation and orientation opportunities in El Portal.

Impacts in Wawona. Under Alternative 1, visitor capacity in Wawona would continue to be controlled primarily through limitations on overnight and day-use parking facilities, as well as other relevant park policies. Continuation of existing user capacity management policies for Wawona would not affect interpretive programs provided at the Wawona Campground Amphitheater, the Pioneer Yosemite History Center in Wawona, or other areas.

Summary of Alternative 1 Impacts. Existing park user capacity management programs for the Merced River corridor are primarily based upon wilderness trailhead quotas and existing facility capacity limits, as well as other management policies as described in Chapter II. Continuation of current user capacity management policies would not be expected to affect access to or the diversity of interpretation and orientation programs offered throughout the corridor.

Cumulative Impacts

Cumulative effects on visitor experience as it relates to orientation and interpretation are based on analysis of past, present, and reasonably foreseeable future actions in the Yosemite region in combination with potential effects of this alternative. The projects identified below include only those projects that could affect visitor interpretation and orientation within the river corridor or in the park vicinity.

Past Actions. Past park projects that affected visitor interpretation and orientation within the river corridor include the Happy Isles Fen Habitat Restoration and the Merced River Ecological Restoration at Eagle Creek. These projects included interpretative signs and facilities to provide information regarding natural systems in the park, resulting in a beneficial effect on interpretation in the river corridor.

Present Actions. Projects currently underway that provide more opportunities for interpretive and orientation include the Cook's Meadow Ecological Restoration and the Lower Yosemite Fall Project. The Yosemite Valley Bus Stop Improvements would also result in a beneficial effect on visitor experience related to increased orientation and interpretation.

Reasonably Foreseeable Future Actions. Reasonably foreseeable future actions proposed in the region are separated below into two general categories: (1) projects anticipated to have a net beneficial effect; and (2) projects anticipated to have both a beneficial and an adverse effect.

Examples of projects that could have a cumulative, beneficial effect on visitor experience as it relates to orientation and interpretation include:

·       Yosemite Village Interim Parking Improvements

·       Indian Cultural Center

These projects could enhance the quality of the visitor experience by increasing interpretation and orientation facilities and services in Yosemite Valley.

Reasonably foreseeable projects that could have both a beneficial and adverse effect include:

·       Update to the Yosemite Wilderness Management Plan

This planning effort could result in increased restrictions in wilderness areas that could affect existing facilities or uses, resulting in an adverse effect on users that currently use these facilities. On the other hand, this could result in a beneficial effect for other user groups who would benefit from a reduction in facilities in the wilderness and enhanced opportunities for solitude and self-guided interpretive experiences.

The past, present, and reasonably foreseeable future projects would have a long-term, minor, beneficial impact, because the beneficial impacts associated with an increase in interpretation and orientation programs and services would only be partially offset by the potential for decreased programs in wilderness areas.

Alternative 1 and the cumulative projects within and in the vicinity of Yosemite National Park would result in a local, long-term, minor, beneficial cumulative impact because the availability and diversity of interpretation and orientation programs and services in the corridor would increase.

Visitor Services

Analysis

The following discussion provides an overview of the types of impacts to visitor services that could occur within each segment of the Merced River corridor under the No Action Alternative. Effects on visitor services from the proposed corridor boundary and management zoning in El Portal are also addressed for the El Portal segment.

Impacts in Wilderness. Under Alternative 1, wilderness areas would continue to be managed under existing wilderness trailhead quotas and other current management policies. Continuation of these policies would not affect the existing low level of visitor services in the Wilderness.

Impacts in Yosemite Valley. Visitor services within the Valley include lodging, food service, and concession-managed activities such as tours and raft rentals. Under Alternative 1, visitor capacity in Yosemite Valley would continue to be managed under existing user capacity policies, including facility limits and specific activity limits. This would not be expected to affect the level of visitor services provided in the Valley, or access to these services. Visitor capacity would continued to be managed primarily through limits on the number of rooms and campsites available for overnight guests, as well as the parking available for day visitors to the Valley. Alternative 1 would not be expected to result in any impacts on the availability of visitor services in the short term. If overnight accommodations and other visitor services are held at existing levels in the future, increased demand for overnight accommodations and other services could result in local, long-term, minor, adverse effects on visitor experience related to access to and availability of visitor services in Yosemite Valley.

Impacts in the Gorge. No visitor services are currently offered in the Gorge segment of the corridor, and continuation of existing user capacity management policies under Alternative 1 would have no effect on visitor services.

Impacts in El Portal. The proposed El Portal segment boundary and management zoning, which focuses on the area's designation as an administrative and operations center, would not be expected to result in any change in the limited visitor services available in El Portal. Visitor services in El Portal are largely run by private businesses (e.g., lodging, restaurants, etc.) on private lands that are not managed under park management policies. The proposed river boundary, zoning, and continuation of existing user capacity management policies under Alternative 1 would not affect visitor services in this area.

Impacts in Wawona. Visitor services in Wawona include lodging, food service, and activities such as horseback riding, golfing, and interpretative programs at the Pioneer Yosemite History Center. Under Alternative 1, the continuation of existing user capacity management policies in Wawona would not affect the level of visitor services provided in the Wawona segments, or access to these services in the short term. If overnight accommodations and other visitor services are held at existing levels in the future, increased demand for overnight accommodations and other services could result in local, long-term, minor, adverse effects on visitor experience related to access to and availability of visitor services in Wawona.

Summary of Alternative 1 Impacts. Continuation of existing user capacity program policies within the Merced River corridor would not be expected to result in any effects on access to or the availability of visitor services in the short term. If overnight accommodations and other visitor services are held at existing levels in the future, increased demand for overnight accommodations and other services could result in local, long-term, minor, adverse effects on visitor experience related to access to and availability of visitor services in Yosemite Valley and Wawona.

Cumulative Impacts

Cumulative effects on visitor experience as it relates to visitor services are based on analysis of past, present, and reasonably foreseeable future actions in the Yosemite region in combination with potential effects of Alternative 1. The projects identified below include only those projects that could affect visitor experience within the river corridor or in the park vicinity.

Past Actions. The El Portal Road Improvements Project, Segments A, B, and C improved transportation to and from the park, which had a beneficial effect on visitor services by providing increased access for visitors staying outside the park. The Rehabilitate Yosemite Valley Campground Restrooms also had a beneficial effect on visitor services by improving the quality of existing visitor facilities.

Implementation of projects prescribed in the Yosemite Valley Plan will have a mixed effect on visitor services. The plan proposes restoration of degraded areas and a reduction of development within the Merced River ecosystem while enhancing the quality of the visitor experience in Yosemite Valley. Reducing automobile congestion, limiting crowding, and expanding orientation and interpretation services may improve visitor services. The plan does, however, prescribe an overall reduction in overnight accommodations in Yosemite Valley, which would have an adverse effect on the provision of visitor services.

Present Actions. Projects currently underway that have a beneficial effect on visitor services include the Yosemite Motels Expansion, the Yosemite Valley Shuttle Bus Stop Improvements, and the Lower Yosemite Fall Project. These projects provide for additional accommodations close to the park and improve visitor facilities in the Yosemite Valley area.

Reasonably Foreseeable Future Actions. Reasonably foreseeable future actions proposed in the region are separated below into two general categories: (1) projects anticipated to have a net beneficial effect; and (2) projects anticipated to have a net adverse effect.

Examples of projects that could have a cumulative beneficial effect on visitor services include:

·        Curry Village and East Yosemite Valley Campgrounds Improvements

·        Wawona Campground Rehabilitation

·        Yosemite Lodge Area Redevelopment

·        Yosemite Village Interim Parking Improvements

These projects are expected to improve and expand campgrounds and campground facilities, improve overnight accommodations and other services at the Yosemite Lodge, and improve parking and traffic circulation for visitors to Yosemite Valley.

A reasonably foreseeable project that could have a net adverse effect on visitor services is the Update to the Yosemite Wilderness Management Plan, which could call for reductions in the level of facilities and activities in wilderness areas. This could change the level of overnight accommodations in wilderness areas, which could be considered an adverse effect on visitor services.

These cumulative projects would have a long-term, minor to moderate, adverse impact on visitor services due to the overall reduction of overnight accommodations in Yosemite Valley and the potential reduction in wilderness areas. These adverse impacts would be partially offset by improving parking and traffic circulation in Yosemite Valley, rehabilitating and expanding some campgrounds in the park, and expanding lodging opportunities outside the park.

Alternative 1 and the cumulative projects within and in the vicinity of Yosemite National Park would result in a long-term, minor to moderate, adverse cumulative impact on visitor services because of the potential reduction of overnight accommodations in Yosemite Valley and potential wilderness areas, and the potential for future increased demand for overnight accommodations. This adverse impact would be partially offset by improving parking and traffic circulation within Yosemite Valley, rehabilitating and expanding some campgrounds in the park, and expanding lodging opportunities outside the park.

Wilderness Experience

Analysis

The following discussion provides an overview of the types of impacts to the wilderness experience that could occur within the Merced River corridor under Alternative 1.

Under Alternative 1, the park would continue to manage use of the Wilderness primarily through the existing trailhead quota system, as well as other relevant management policies. Alternative 1 would not result in any change to wilderness access or the opportunities for solitude and primitive recreation.

Summary of Alternative 1 Impacts. There would be no change to the wilderness experience under Alternative 1.

Cumulative Impacts

Cumulative effects on the wilderness experience are based on analysis of past, present, and reasonably foreseeable future actions in the Yosemite region in combination with the effects of this alternative. The projects identified below include only those projects that could affect the wilderness experience within the river corridor or in the park vicinity.

Past Actions. Past restoration and rehabilitation projects in wilderness areas, such as trail maintenance and illegal campsite restoration, improved the wilderness experience by restoring and improving trail conditions and restoring meadow environments near trails. The recently completed Fire Management Plan (NPS 2004) is expected to result in local, long-term, beneficial effects on the wilderness experience by improving natural conditions.

Present Actions. The Wilderness Trailhead Quota System continues to limit and/or disperse use based on trailhead access, and thus provides the beneficial impact of improved experience of natural values due to resource protection.

Reasonably Foreseeable Future Actions. Reasonably foreseeable future actions proposed in the region are separated below into two general categories: (1) projects anticipated to have a net beneficial effect; and (2) projects anticipated to have both a beneficial and adverse effect.

The Red Peak Pass Trail Rehabilitation could have a net beneficial effect on visitor experience by improving ecosystem health in wilderness areas within the park, restoring meadows, and improving trails. Any improvement to the wilderness ecosystem is considered to be a long-term, beneficial impact.

The update to the Yosemite Wilderness Management Plan is expected to have both beneficial and adverse effects. This update could call for a reduction in existing facilities or activities in wilderness areas. This change could reduce overnight accommodations in wilderness areas, resulting in an adverse effect to some visitors. On the other hand, this action might also result in a beneficial effect for other user groups whose access to the wilderness would not be affected, but who would benefit from a reduction in facilities and activities in the wilderness. These individuals could benefit from improvements in scenic and natural quiet qualities, opportunities for solitude, and an overall primitive recreational experience.

These cumulative projects would have a long-term, minor, beneficial impact on the wilderness experience, because the wilderness ecosystem would be improved and would only be partially offset by the potential, long-term, adverse impacts related to additional restrictions on activities and facilities in wilderness areas.

Alternative 1 and the cumulative projects within and in the vicinity of Yosemite National Park would result in a long-term, minor, beneficial cumulative impact to the wilderness experience, because the beneficial improvements to the wilderness ecosystem would offset the potential reductions in wilderness facilities and activities.

Social Resources

Land Use

Analysis

The following discussion provides an overview of the types of impacts to land use that could occur within each segment of the Merced River corridor under the No Action Alternative. The analysis for the El Portal segment also describes the types of impacts to land use that could occur based on implementation of the narrow river corridor boundary and management zoning proposed for El Portal under this alternative.

The park establishes management zoning to classify park areas and prescribe future desired resource conditions, visitor activities and use levels, and appropriate facilities. Management zones in the river corridor were established in the Merced River Plan. These management zones place an emphasis on integrating protection and enhancement of the natural and cultural resources identified as ORVs with the protection and enhancement of the spectrum of recreational experiences identified in the recreation ORVs. Management zoning sets the goals for each area; the park implements user capacity management measures to help achieve the goals set out in the management zoning prescriptions.

Impacts to Wilderness. User capacity measures implemented under Alternative 1, including the existing wilderness trailhead quotas, would be consistent with the management zoning developed in the Merced River Plan and with the existing land uses in the Wilderness segments of the river corridor.

Impacts to Yosemite Valley. User capacity measures implemented under Alternative 1, including facility and specific activity limits, would be consistent with the management zoning developed through the Merced River Plan and with existing land uses in the Yosemite Valley segment.

Impacts to the Gorge. User capacity measures implemented under Alternative 1, including facility and specific activity limits, would be consistent with the management zoning developed through the Merced River Plan and with existing land uses in the Gorge segment.

Impacts in El Portal. Under Alternative 1, the river corridor boundary in the El Portal segment would include 193 acres, of which 137 acres would be zoned for day use (2C) and the other 56 acres would be zoned for administrative uses (3C). The 3C zoning designation would allow for development of some additional park administrative facilities and 2C zoning would allow for development of some day use facilities. Development within the corridor would be limited to facilities that meet the requirements of the Wild and Scenic Rivers Act, including the protection and enhancement of the ORVs. The potential residential and administrative types of development that would likely occur in the future would be consistent with existing development patterns. Areas outside the corridor boundary could also be developed, to the extent that any ORVs located outside the river corridor are protected. The potential for increased development in the El Portal segment, both inside and outside the corridor boundary, would result in more residential and administrative development and less open space. Development would likely increase, resulting in a local, long-term, minor to moderate, adverse effect on land use in El Portal.

User capacity measures implemented under Alternative 1, including facility and specific activity limits, would be consistent with the management zoning established for the El Portal segment under this alternative.

Impacts to Wawona. User capacity measures implemented under Alternative 1, including facility and specific activity limits, would be consistent with the management zoning developed through the Merced River Plan and with existing land uses in Wawona.

Summary of Alternative 1 Impacts. Under Alternative 1, the park would continue to implement existing user capacity policies, including wilderness trailhead quotas, facility limits, and specific activity limits. Since these existing user capacity policies are designed to help the park achieve the goals defined in the management zoning prescriptions, implementation of Alternative 1 would be consistent with management zoning in the river corridor. The proposed river corridor boundary and management zoning in El Portal could result in local, long-term, minor to moderate, adverse effects on land use due to the potential for increased residential and administrative development and a decrease in open space in the El Portal area.

Cumulative Impacts

Cumulative effects to land use are based on an analysis of past, present, and reasonably foreseeable future actions in combination with the potential effects of this alternative. The projects identified below include only those projects that could affect land use within the river corridor and in the immediate vicinity of Yosemite National Park.

Past Actions. In general, land uses in the Merced River corridor have been determined by past decisions on the development, relocation, and removal of specific facilities. Development within the Merced River corridor has occurred since Euro-American occupation.

In 1991, the U.S. Forest Service and the Bureau of Land Management developed a joint South Fork and Merced Wild and Scenic River Implementation Plan for the segments of the main stem and South Fork of the Merced River that are under their jurisdiction. The plan is also a general management plan with many prescriptive goals and few specific actions. The plan endeavors to limit or end consumptive uses such as grazing within the river corridor and calls for the formalization of camping and launch facilities for nonmotorized watercraft. By eliminating impacts where feasible (grazing does not currently occur within the river corridor), concentrating impacts in areas able to withstand visitor use, and providing facilities that mitigate adverse effects associated with visitor use (e.g., restrooms), implementation of these actions has a beneficial effect.

The Yosemite Valley Plan calls for relocation of facilities out of Yosemite Valley to El Portal and Wawona and for redevelopment of areas within Yosemite Valley. All of the changes proposed are consistent with the types of development already in the river corridor segments and with the land use zoning established in the Merced River Plan. The changes proposed in this plan would result in an adverse effect on existing land use in El Portal and Wawona as open space areas are developed for residential uses and administrative uses. The intensity of the effect would depend upon the extent to which the proposed development in the plan is implemented.

Present Actions. The Mariposa County General Plan Update would evaluate and address countywide land use issues and is expected to benefit land use throughout the county. The Yosemite Motels Expansion project, a privately sponsored project, would be expected to have local, long-term, adverse effects on land use in El Portal associated with the increased intensity of development adjacent to El Portal.

Reasonably Foreseeable Future Actions. The El Portal Concept Plan will evaluate development opportunities and constraints in El Portal and evaluate the potential for relocation of employee housing and other park administrative facilities from the Valley to El Portal. The impact intensity of this project would depend upon the intensity of development proposed and the extent to which the Concept Plan addresses compatibility with existing land uses in El Portal. The long-term impacts on land use could be either adverse or beneficial.

Overall, the cumulative projects would be expected to have local, long-term, minor to moderate, adverse impacts on land use due to the potential for additional development of residential and administrative uses and a decrease in open space in the El Portal area and Wawona areas. The impacts should be offset somewhat by the planning efforts underway on countywide planning and the El Portal Concept Plan.

The cumulative effects of Alternative 1 and the cumulative projects would result in local, long-term, minor to moderate, adverse effects on land use within the river corridor.

Transportation

Analysis

The following discussion provides an overview of the types of transportation impacts associated with Alternative 1, the No Action Alternative. Because transportation services and facilities are not provided in Yosemite wilderness areas, this discussion does not address impacts in the Wilderness segments of the river corridor.

In general, transportation conditions would remain unchanged under Alternative 1, although traffic levels would be expected to increase over time. Traffic levels during peak periods would continue to adversely affect transportation due to congestion on roads and in parking areas. Visitor parking would occasionally spill into natural areas along roadsides, resulting in conflicts among parked and moving vehicles. Pedestrian traffic from roadside parking to activity areas would conflict with moving traffic. The park would continue to occasionally implement restricted access programs in response to traffic and safety conditions. If visitation grows in the future, these impacts would become more frequent and more intense.

Impacts in Yosemite Valley. At present, visitor travel to Yosemite Valley is not actively controlled on a daily basis, but it is regulated through facility capacities. For the transportation system, capacities are primarily determined by the parking supply. Several traffic bottlenecks, where high volumes of pedestrians cross major roadways, affect transportation conditions during peak travel periods. During these peak periods, park staff direct visitors to available parking and manage vehicle and pedestrian traffic at several congested intersections. Park employees direct visitors to roadside parking areas when parking lots are full. On the busiest days the roadside parking can spill into natural areas. Visitors may experience delays in accessing recreation sites due to the time spent searching for parking. High visitation on weekends in the peak season sometimes results in significant traffic congestion within Yosemite Valley. This congestion primarily affects visitors and other travelers as they exit the Valley via Northside Drive. A line of waiting vehicles typically backs up along Northside Drive from the intersection at Yosemite Lodge. The line can reach to Yosemite Village and beyond on the busiest afternoons. The congestion from private vehicle traffic delays the operation of the Yosemite Valley Shuttle Bus system, thus reducing its effective capacity and causing overcrowding of the buses during peak times. Park management implements restricted access to the Valley when it determines that local traffic congestion is creating unacceptable human safety, visitor experience, and resource impacts. Restricted access results in the diversion of visitor and other traffic away from roads in Yosemite Valley and onto other roads in the park.

Under Alternative 1, for the short term there would continue to be negligible to minor, adverse impacts on the transportation system during peak periods. In the long term, these adverse effects related to parking and congestion could increase as a result of growth in visitation, primarily extending into additional time periods and on additional days. If they become more frequent and/or more widespread in time, the impacts could increase to local, minor to moderate, and adverse.

Impacts in the Gorge. Current access to the Merced River gorge is limited by available roadside parking along the shoulders of Highway 140 and at two off-road parking areas. Parking availability effectively limits the capacity for visitors who can access this segment of the Merced River.

Under Alternative 1, user capacity would continue to be limited through the existing parking supply in the Gorge segment. Available parking fills relatively infrequently in this area, and additional use could occur during off-peak times. When restricted access is implemented for Yosemite Valley, the parking spaces in the Gorge are likely to become more congested as visitor use is displaced away from the Valley. The existing parking supply in the Gorge would limit the degree to which displaced users from the Valley could be accommodated. If park visitation increases, parking areas in the Gorge could be filled more regularly. If demand is increased by traffic diversion from the Valley, parking may begin to spill onto the shoulders of the road near the current spaces. This could create safety issues for the vehicles parking along Highway 140 in the Gorge and could cause conflicts with through traffic on Highway 140.

Under Alternative 1, for the short term there would be negligible impacts on the transportation system of the Gorge. In the long- term, there could be local, negligible to minor, adverse effects related to parking availability and traffic safety conflicts during peak periods.

Impacts in El Portal. There are no established visitor facilities on National Park Service land in the El Portal segment of the Merced River. Transportation access to river activities is from Highway 140 and Foresta Road via informal parking areas along the shoulders of both roads. There is also a small gravel parking lot for the existing Red Bud commercial raft launch site at the western edge of the El Portal segment. The boundary and management zoning under Alternative 1 would maintain a narrow boundary in El Portal, which would allow for future development of administrative and visitor use facilities in areas outside the corridor. Increased development of employee housing or visitor facilities could result in increased traffic in the areas and would likely result in a local, long-term, minor, adverse effect on transportation conditions in this segment.

Under Alternative 1, user capacity would continue to be limited through the existing parking supply in El Portal. Available parking fills relatively infrequently in this area, and additional use could occur during off-peak times. The existing supply of parking in El Portal would be expected to limit future use of this area to the current peak level of use. Growth in visitor use (primarily rafting and fishing) in the area could result in the parking areas filling more frequently. If parking capacity were exceeded, parking would begin to spill onto the shoulders of the roads near the current spaces. This could create safety issues for the vehicles parking along roadways and could cause conflicts with through traffic.

Overall, Alternative 1 would be expected to result in a local, long-term, negligible to minor, adverse effect on the transportation system in El Portal.

Impacts in Wawona. At present, visitor traffic in the Wawona segments is not actively managed on a daily basis, but is regulated through the capacity of the overnight lodging and parking areas. Parking is actively managed during limited peak periods. The active management of the visitor parking lot at the Mariposa Grove directly affects transportation conditions in Wawona. When the Mariposa Grove lot fills, visitors' vehicles are diverted to other parking areas and visitors travel to the grove via shuttle. Much of the displaced parking occurs in Wawona, primarily near the Wawona Store. The displaced parking from Mariposa Grove frequently causes the parking lot at the store to fill. On many days visitors park vehicles along the road shoulders of Highway 41 and Forest Drive. Some visitors who want to use facilities at Wawona, including the store and the Pioneer Yosemite History Center, may be displaced by the overflow parking conditions.

Under Alternative 1, visitor transportation in the Wawona segment would continue to be controlled by the existing parking supply in the Wawona area. During peak periods when restricted access is implemented for Mariposa Grove, the parking spaces in Wawona could become more congested. If park visitation increases, parking areas in Wawona could be filled more frequently. If sufficient demand is created by traffic diversion from Mariposa Grove or the Valley, parking may begin to spill into additional roadside areas. This could create safety issues for the vehicles parking along Highway 41 and Forest Drive and cause conflicts with through traffic on Highway 41.

Under Alternative 1, for the short term there would be negligible impacts on the transportation system of the Wawona area. In the long term, there could be local, negligible to minor, adverse effects related to access and traffic congestion during peak periods.

Summary of Alternative 1 Impacts. Alternative 1 would continue existing user capacity programs for areas within the Merced Wild and Scenic River corridor. For the short term, continuation of these existing user capacity programs would be expected to result in local, short-term, negligible to minor, adverse effects on the transportation systems. In the long term, Alternative 1 could result in local, negligible to minor, adverse effects on the transportation system.

Cumulative Impacts

Cumulative impacts on transportation are based on analysis of past, present and reasonably foreseeable future actions in the Yosemite region in combination with potential effects of Alternative 1.

Past Actions. Past actions that have affected transportation include the El Portal Road Improvements Project (Segments A, B, and C) and the development of the Yosemite Valley Plan. The El Portal Road Improvements Project has provided a minor, long-term, beneficial impact to transportation as it has improved road conditions and safety concerns between the Yosemite National Park boundary and the intersection of the El Portal and Big Oak Flat Roads. The Yosemite Valley Plan would implement major changes in transportation to and within Yosemite Valley. The number of private vehicle trips by visitors to and within the Valley would be reduced significantly. Implementation of projects under the Yosemite Valley Plan would result in local, long-term, moderate to major, beneficial transportation impacts.

Present Actions. Current projects underway include the South Fork Bridge Replacement, Yosemite Valley Shuttle Bus Procurement, and Yosemite Valley Shuttle Bus Stop Improvements. These current projects would likely result in long- term, minor, beneficial impacts on transportation.

Reasonably Foreseeable Future Actions. The reasonably foreseeable future actions proposed in the region are all expected to have beneficial impacts on the transportation system or the demand for transportation services in the river corridor or the park. These projects include Yosemite Village Interim Parking Improvements, El Portal Concept Plan, El Portal Road Improvements Project (Segment D), Northside-Southside Drive Repaving, and the Yosemite Lodge Area Redevelopment. The Northside-Southside Drive Repaving would provide long- term, minor, beneficial, localized improvements to existing transportation problems, primarily in the areas of safety and efficiency of the transportation system. The Yosemite Village Interim Parking Improvements project would improve some existing traffic congestion points in the Valley and would facilitate the management of parking spaces for day visitors, resulting in minor, beneficial transportation benefits. The Yosemite Lodge Area Redevelopment project would remove the single greatest traffic congestion point in Yosemite Valley, which when combined with Alternative 1 could result in minor to moderate, long- term, beneficial transportation impacts. The El Portal Concept Plan, if successfully implemented, would relocate employee housing and work sites away from Yosemite Valley. This would reduce travel within the Valley by a small amount and result in negligible transportation benefits.

Scenic Resources

Analysis

The following discussion provides an overview of the types of impacts to scenic resources that could occur within each segment of the Merced River corridor under Alternative 1.

Impacts in the Wilderness. Scenic ORVs of the Wilderness segments of the river corridor include views from the Merced River and its banks of the exposed bedrock riverbed, Merced Lake and Washburn Lake, the Bunnell Cascade, the confluence of tributaries, a large concentration of granite domes, and the Clark and Cathedral Ranges. Park management practices and use levels would continue to be based on the Wilderness Act and federal and Yosemite National Park wilderness policies and guidelines, such as the trailhead quota system (which limits and disperses visitor use) and WIMS. Because of the remote location of the Wilderness segments of the river and the low levels of use, continuation of current management direction under Alternative 1 is not expected to affect scenic ORVs.

Impacts in Yosemite Valley. Scenic ORVs within Yosemite Valley include views from the Merced River and its banks of waterfalls and water features (Nevada, Vernal, Illilouette, Yosemite, Sentinel, Ribbon, and Bridalveil Falls and Silver Strand), rock cliffs (Half Dome, North Dome/Washington Column, Glacier Point, Yosemite Point/Lost Arrow Spire, Sentinel Rock, Three Brothers, Cathedral Rocks, and El Capitan), and meadows (Stoneman, Ahwahnee, Cook's, Sentinel, Leidig, El Capitan, and Bridalveil). There is a scenic interface of river, rock, meadow, and forest throughout the Valley segment.

Under Alternative 1, the National Park Service would continue to implement existing user capacity policies. These policies are consistent with the management zoning prescribed in the Merced River Plan and are not expected to adversely affect scenic resources.

Many of scenic resources are insensitive to user-related impacts and would be more directly affected by development within the river corridor, which could result in a loss of vegetative cover and an increase in structures and facilities that could obstruct scenic views.

Alternative 1 would protect and enhance the scenic ORVs through the application of a range of management zones.

Areas zoned Open Space (and Undeveloped Open Space) (2A), Discovery (2B), and Day Use (2C) are designed to enhance scenic ORVs by placing restrictions on new development and encouraging restoration activities. Measures taken to enhance ORVs include closure or restoration of riparian areas and site hardening, such as construction of boardwalks or picnic facilities. New facilities in these management zones are designed in accordance with the Yosemite Valley design guidelines (NPS 2004c), which guides facility design to promote scenic values. Continuing the current method of managing these zones would have a local, long-term, minor to moderate, beneficial impact on scenic resources and the scenic ORVs.

To further protect and enhance the ORVs in other parts of the corridor, areas zoned Camping (3A), Visitor Base and Lodging (3B), and Park Operations and Administration (3C) direct high-impact activities and facilities to areas better able to withstand heavy use or to already developed locations. Potential projects in these developed zones that could affect scenic resources include additional development, vegetation removal, and increased intensity of use. Although new design would follow the park's design guidelines, increased development density, surface hardening, vegetation removal, and increased visitor use (and consequent decrease in opportunities for solitude) would have a local, long-term, minor, adverse impact on scenic resources.

Impacts in the Gorge. Scenic ORVs of the Gorge segment include views from the Merced River and its banks of the Cascades, spectacular rapids among giant boulders, Wildcat Fall, Tamarack Creek Fall, the Rostrum, and Elephant Rock. The extensive application of 2A+, 2A, and 2B zoning and the quarter-mile boundary over a majority of the Gorge segment would protect and enhance these ORVs. Management zoning in the Gorge segment would substantially limit areas in which new development could occur and would maintain the natural appearance of the gorge, thus ensuring the protection of the scenic ORVs.

Under Alternative 1, the National Park Service would continue to implement existing user capacity policies. These policies are consistent with the management zoning prescribed in the Merced River Plan and are not expected to affect scenic resources.

Impacts in El Portal. Scenic resources in the El Portal segment of the river corridor consist of views of the geologic transition between granite and metasedimentary bedrock along the canyon walls and distinct views of Chinquapin Fall.

Portions of El Portal would be zoned 3C (e.g., the Trailer Village/Abbieville, Old El Portal), which could allow additional development. Since the river corridor boundary is narrow under Alternative 1, there is more potential for development in El Portal in those areas outside the corridor boundary. Such development could change the quality of the visual landscape within the Merced River corridor and could have local, long-term, minor, adverse effects on the scenic resources in El Portal. Implementing mitigation measures described in Appendix B could mitigate adverse effects. The adverse impact on scenic resources in El Portal could be further offset by the potential restoration of the Sand Pit, resulting in a negligible, adverse impact.

Impacts in Wawona. Scenic ORVs of the Wawona segments of the river corridor include views from the Merced River and its banks of large pothole pools within slickrock cascades, old-growth forest, meadows, Wawona Dome, and continual whitewater cascades in the deep and narrow river canyon below Wawona.

Under Alternative 1, park management would continue to implement existing user capacity policies. These policies would be consistent with the management zoning prescribed in the Merced River Plan and would not be expected to adversely affect scenic resources.

Summary of Alternative 1 Impacts. Compliance with existing park policies, including the Yosemite Valley design guidelines, would help ensure that the scenic ORVs in the Wilderness, Yosemite Valley, Gorge, and Wawona segments are protected and enhanced. Application of existing management zoning and other user capacity policies would have a local, long-term, minor, beneficial impact on scenic resources and the scenic ORVs in Yosemite Valley and Wawona due to opportunities to restore degraded areas of the Merced River corridor and remove developments inconsistent with the River Protection Overlay. This beneficial impact would be partially offset by management zoning that would allow for some new development. In the El Portal segment, Alternative 1 would have a minor, adverse impact on scenic resources due to the potential for new development in El Portal. This adverse impact could be partially offset by the restoration of the Sand Pit.

Cumulative Impacts

Cumulative effects on scenic resources are based on analysis of past, present, and reasonably foreseeable future actions in the Yosemite region. The projects identified below include only those projects that could affect scenic resources within the Merced River corridor or in the park vicinity.

Past Actions. Scenic resources have been affected by numerous past actions since the inception of the park. Primary among these is the alteration of natural communities caused by Euro-American settlers who lived in the park. For example, attempts to establish agriculture and the development of tourism resulted in the drying out of the Valley by breaching the El Capitan moraine and suppressing naturally occurring fires, which affected vegetation patterns along the Merced River. Broad-leafed trees along the riverbanks were replaced by the comparatively dense stands of conifers that exist today. These activities have had a local, long-term, moderate, adverse effect on scenic resources, because the conifers now block views of important scenic resources that were visible before the vegetation patterns were changed.

Recent park projects that have benefited scenic resources within the river corridor include the Fire Management Plan, which addresses improvements to ecosystem health through integration of fire management principles and other vegetation management principles, and the Cascades Diversion Dam Removal, which restored the natural flow of the Merced River at the top of the Gorge segment, thereby improving scenic resources.

Projects implemented under the Yosemite Valley Plan could include improvements to the natural setting through restoration and improved site design. Adverse effects on scenic resources could occur in areas of new development.

Present Actions. Current projects that adversely affect scenic resources due to increased development and obstruction of views include the Yosemite Motels Expansion in El Portal and the Curry Village Employee Housing in Yosemite Valley.

Reasonably Foreseeable Future Actions. Reasonably foreseeable future actions proposed in the region are separated below into three general categories: (1) projects anticipated to have a net beneficial effect; (2) projects anticipated to have both adverse and beneficial effects; and (3) projects anticipated to have an adverse effect.

Projects that could have a net beneficial cumulative effect on scenic resources include those that improve the built environment to better address significant views. Examples of projects that could have a beneficial cumulative, effect on scenic resources include:

·       Yosemite Lodge Area Redevelopment

·       Visitor Use and Floodplain Restoration Program

·       El Portal Old Wastewater Treatment Facility Removal

Projects that prescribe increased development--especially development in previously undeveloped areas--would have a long-term, moderate, adverse impact to scenic resources. Examples of projects that could have both adverse and beneficial effects on scenic resources include:

·       El Portal Concept Plan

·       Tuolumne Meadows Concept Plan

·       Tuolumne Wild and Scenic River Comprehensive Management Plan

·       Update to the Yosemite Wilderness Management Plan

All four of these plans could improve the natural setting through restoration and improved site design. Adverse effects on scenic resources could occur in areas of new development.

Examples of projects that could have a adverse cumulative effect on scenic resources include:

·       Environmental Education Campus Development Program

·       Indian Cultural Center

·       Yosemite Village Interim Parking Improvements

The local, long-term, adverse effects of these projects would be related to the potential introduction of new structures and infrastructure that would intrude into views of important scenic resources within or viewable from the Merced River corridor. For example, the Yosemite Village Interim Parking Improvements could result in a decrease in vegetation, an increase in the glare caused by parked vehicles, and an increase in hardscape. The effects of this development would be visible from important Valley-rim viewpoints such as Glacier Point. The Indian Cultural Center would introduce new structures into a currently undeveloped part of the Valley and would adversely affect foreground views.

These past, present, and foreseeable future projects would have a long-term, minor, adverse impact because the beneficial effects associated with restoration, vegetation management, and vehicle reduction would be slightly outweighed by the potential for increased development and a decreased ability to view and experience scenic resources.

Overall, these cumulative actions in combination with Alternative 1 could have a net long-term, minor, adverse impact on scenic resources and the scenic ORVs within the Merced River corridor.

Impairment

Because impacts associated with Alternative 1 are expected to be beneficial or only negligibly adverse, this alternative would not be expected to impair the park's scenic resources for future generations.

Socioeconomics

Social Environment

Analysis

Under Alternative 1, park management would continue to manage user capacity based on current policies, including wilderness trailhead quotas, facility limits, and limits on specific activities. The river corridor for the El Portal segment would be the same as identified in the Merced River Plan.

Since the No Action Alternative would not change existing policies regarding facilities and operations within the river corridor segments, there would be no substantive changes to the social environments within the river corridor. Existing housing, community amenities, and other facilities could continue to be used as they are currently. Commute times to and from the park from various areas would likely increase in the future, because overall visitation to the park would result in increased traffic on roads used for commuting.

Impacts in Wilderness Areas. There are limited facilities in park wilderness areas, and few employees are stationed in these areas. User capacity would continue to be managed under the existing trailhead quotas, and visitor and employee levels would be expected to remain at current levels. The No Action Alternative is not expected to affect the social environment in Wilderness segments of the river corridor.

Impacts in Yosemite Valley. The No Action Alternative would not require changes to existing employee housing, available amenities, or other facilities in the Valley. Park planning efforts and future development in the Valley would continue to be based on the General Management Plan and on existing utility capacities within the Valley. Since the General Management Plan calls for reduced administrative facilities in the Valley, employee housing in the Valley would likely decrease in the future. Commute times to the Valley from other areas are not expected to change in the short term, but could increase in the long term with increases in park visitation and traffic levels on roads leading to the park. Overall, effects from Alternative 1 on the social environment would likely be local, long-term, minor, and beneficial due to decreased crowding in Yosemite Valley. Effects on employees relocated out of the Valley would be local, minor to moderate, and adverse due to increased commutes over time. The intensity of the adverse effect would depend upon the level of housing increases or decreases and where this employee housing was replaced.

Impacts in El Portal. Continuation of user capacity management policies under the No Action Alternative would not require changes to employee housing in El Portal, amenities, or other facilities located there. Park planning efforts and future development in El Portal would continue to be based on the General Management Plan and on existing utility capacities. Since the General Management Plan calls for increased employee housing in El Portal, it is likely that the level of employee housing would increase in the future, while remaining within utility capacities.

The river corridor boundary and management zoning in El Portal under Alternative 1 is consistent with existing uses of the corridor and would not expected to require changes to housing, community amenities, or facilities. The narrow corridor boundary would allow for future development of new or expanded park administrative facilities outside the corridor in the El Portal area. Future increased development within the El Portal Administrative Site could result in local, long-term, minor to moderate, adverse effects on community amenities due to the potential for increased administrative staff and/or employee housing in the area. The intensity of the impacts would depend on the level of development within the El Portal Administrative Site.

Impacts in Wawona. The No Action Alternative would not change how user capacity is currently managed in Wawona. Therefore, there would be no changes to housing, community amenities, or other facilities. Park planning efforts and future development in Wawona would continue to be based on the General Management Plan and on existing utility capacities. Park staffing and employee housing in Wawona could increase or decrease in the future, within the limits of the utility capacities. The General Management Plan calls for increased employee housing in Wawona; therefore, employee housing would likely increase in the future, within the limits of the utility capacities. Commute times to Wawona from other areas would not be expected to change in the short term, but could increase in the long term with increases in park visitation and traffic levels on roads leading to the park. Overall effects from Alternative 1 on the social environment are expected to be local, long-term, minor to moderate, and adverse due to changes in housing levels and increased commutes over time. The intensity of the adverse effect would depend upon the level of housing increases or decreases and where this employee housing was replaced.

Summary of Alternative 1 Impacts. The continuation of user capacity policies within the river corridor would not require substantive changes to existing housing and facilities in the local communities within the corridor. Housing and staffing in these areas could increase or decrease in the future, within the limits of the existing utility capacities. Commute times would not be expected to change in the short term, but could increase in the long term with increases in park visitation and traffic levels on roads leading to the park. Overall effects from Alternative 1 on the social environment are expected to be local, long term, minor to moderate, and adverse due to potential changes in housing levels and increased commutes over time. The intensity of the adverse effect would depend upon the level of housing increases or decreases and where this employee housing was replaced.

Cumulative Impacts

This discussion of the cumulative effects on the social environment is based on analysis of past, present, and reasonably foreseeable future actions in the Yosemite region in combination with potential effects of this alternative.

Past Actions. The Yosemite Valley Plan, completed in 2000, provides guidance for the relocation of park and concessioner employee housing and other administrative facilities from the Valley to El Portal and Wawona, as called for in the General Management Plan. Implementation of this plan would result in mixed effects on the social environments in the river corridor. The social environment in Yosemite Valley would experience local, long-term, beneficial effects associated with reduced crowding, more secure housing conditions, and increased privacy. The social environment of the workforce would also experience local, long-term, adverse effects associated with increases in commuting time, changes of housing locale, and decreases in social amenities near housing sites. The social environment in El Portal and Wawona would experience local, long-term, adverse effects due to the potentially substantial increases in housing in these communities, although it is expected that the population growth would be gradual. Even though the Yosemite Valley Plan calls for the placement of community amenities in El Portal, there could be strains on the limited community amenities of El Portal and Wawona resulting from the population growth.

Present Actions. Current projects include projects that benefit the social environment and projects that adversely affect the social environment in the river corridor.

The Mariposa County General Plan Update and the Curry Village Employee Housing project are expected to benefit the social environment in the corridor. The Curry Village Employee Housing project provides for new, efficiently designed employee housing to replace crowded temporary housing areas that were developed after the January 1997 flood. The Mariposa County General Plan Update will evaluate and address countywide land-use issues and is expected to benefit the social environment throughout the county.

The Yosemite Motels Expansion project is expected to have short- and long-term, adverse effects on the social environment in El Portal. This project could result in short-term construction effects and in longer term effects related to increased development and traffic congestion in the El Portal area.

Reasonably Foreseeable Future Actions. Reasonably foreseeable future actions proposed in the region are separated below into three general categories: (1) projects anticipated to have a net beneficial effect; (2) projects anticipated to have a net adverse effect; and (3) projects anticipated to have a mixed effect.

A reasonably foreseeable future project that could have a cumulative, beneficial effect on the social environment is:

·       El Portal Concept Plan

The El Portal Concept Plan will evaluate development opportunities and constraints in El Portal and evaluate the potential for relocation of employee housing and other park administrative facilities from the Valley to El Portal. This planning effort would be expected to develop a design plan that protects the ORVs in the El Portal segment and provides for needed amenities that will benefit the social environment in El Portal.

Together, the past, present and reasonably foreseeable future projects would have a local, long-term, minor to moderate, adverse effect on the social environments within the corridor due to increased housing and population pressures in El Portal and Wawona and increased commutes for employees relocated from the Valley. The impact intensity of any planning projects would depend on the extent to which the plan's recommendations are implemented.

Alternative 1 and the cumulative projects would have a local, long-term, minor to moderate, cumulative, adverse effect on the social environments within the corridor due to increases in housing and population pressures in El Portal and Wawona. The impact intensity would depend on the extent to which the cumulative projects' recommendations are implemented.

Visitor Populations

Analysis

Alternative 1 would provide for the continued implementation of existing park policies regarding visitor use within the river corridor. These include wilderness trailhead quotas, facility limits, and limits on specific activities. These policies would allow for continued growth in visitor populations to the point where visitation is constrained by existing facilities (i.e., lodging and parking). In the long-term, Alternative 1 could result in higher visitation levels in the future resulting in a need for increased use of restricted access policies. The level of overnight accommodations for visitors in the park would remain consistent with the overall developed area capacities identified in the General Management Plan and would be constrained by existing utility capacities. Under Alternative 1, the composition of the Yosemite visitor population (the ratio of park overnighters to day visitors) is not expected to change from existing conditions.

Summary of Alternative 1 Impacts. Alternative 1 is not expected to result in any substantive changes in visitor populations in the park. Long-term increases in visitor levels would likely result in increased use of restricted access policies during peak periods.

Cumulative Impacts

This discussion of cumulative impacts on visitor populations is based on analysis of past, present, and reasonably foreseeable future actions in the Yosemite region in combination with potential effects of this alternative.

Past Actions. The Yosemite Valley Plan, completed in 2000, provides for a reduction in overnight accommodations in Yosemite Valley, which would result in a local, long-term, adverse impact on visitors due to decreased opportunities to lodge and camp in the Valley.

Present Actions. The Yosemite Motels Expansion project provides for additional overnight accommodations close to the park. This project is expected to result in a local, long-term, beneficial effect on visitor populations.

Reasonably Foreseeable Future Actions. Reasonably foreseeable future projects that could have a cumulative, beneficial effect on visitor populations include:

·       Curry Village and East Yosemite Valley Campgrounds Improvements

·       Yosemite Lodge Area Redevelopment

These projects would result in the development of some new overnight accommodations in the Curry Village and Yosemite Lodge areas. These projects would have a local, long-term, beneficial impact on visitor populations by increasing overnight accommodations in the park.

The cumulative projects would have a regional, long-term, negligible to minor, adverse impact on visitor populations due to the overall reduction in overnight accommodations in Yosemite Valley. This adverse effect would be offset somewhat by additional overnight accommodations being constructed outside the park.

Overall, Alternative 1 and the cumulative projects within and in the vicinity of Yosemite National Park would result in a local, long-term, negligible to minor, adverse impact on visitor populations, due to the potential overall reduction in the number of lodging and camping units in the park. This effect is offset somewhat by development of overnight accommodations in areas outside the park.

Regional Economy

Analysis

Under Alternative 1, the number of overnight accommodations and the composition of the Yosemite visitor population are not expected to change substantively from existing conditions. Yosemite visitor spending in the region would be expected to increase with increased visitor levels, resulting in a local, long-term, negligible to minor, beneficial effect on the regional economy. Alternative 1 is not expected to result in any shifts in regional employment.

Summary of Alternative 1 Impacts. Under Alternative 1, visitor populations and visitor spending would be expected to increase in the long-run, resulting in a regional, long-term, negligible to minor, benefit to the regional economy.

Cumulative Impacts

The cumulative impacts to the regional economy discussed in this section are based on analysis of past, present, and reasonably foreseeable future actions in the Yosemite region in combination with potential effects of this alternative.

Past Actions. The Yosemite Valley Plan, completed in 2000, calls for substantial construction associated with the relocation of administrative and employee housing facilities and redevelopment of areas within Yosemite Valley. This would have a short-term, beneficial impact on the regional economy due to project construction spending and employment. In the long term, the Yosemite Valley Plan would decrease in-park accommodations and increase accommodations outside the park. Overall, the economic impacts to the regional economy of changes from visitor spending and operations spending are expected to be long-term and beneficial.

Present Actions. Current projects that affect the regional economy include the Yosemite Motels Expansion, Yosemite Valley Shuttle Bus Stop Improvements, Utilities Master Plan/East Yosemite Valley Utilities Improvement Plan, Resources Management Building, South Fork Bridge Replacement, and Curry Village Employee Housing. Construction spending associated with these projects is expected to have a short-term, beneficial impact on the regional economy due to project construction spending and employment.

Reasonably Foreseeable Future Actions. Reasonably foreseeable future projects that could have a cumulative, beneficial effect on the regional economy include:

·       Curry Village and East Yosemite Valley Campground Improvements

·       El Portal Road Improvements Project (Segment D)

·       Indian Cultural Center

·       Yosemite Lodge Area Redevelopment

·       Wawona Campground Rehabilitation

·       Yosemite Village Interim Parking Improvements

These projects are expected to have a short-term, beneficial impact on the regional economy due to project construction spending and employment. Development of new campgrounds and cabins near Curry Village would increase the overnight lodging capacity in Yosemite Valley somewhat, which would increase visitor spending and benefit the regional economy.

These cumulative projects would have a short-term, minor, beneficial effect on the regional economy, primarily due to construction spending and employment. The cumulative projects would have a long-term, negligible to minor, beneficial effect on the regional economy due to increased regional output and employment resulting from increased overnight accommodations in the park and in local communities.

Overall, Alternative 1 and the cumulative projects within and in the vicinity of Yosemite National Park would result in a cumulative, short-term, minor, beneficial impact on the regional economy due to construction spending and employment and a long-term, negligible to minor, beneficial impact on the regional economy due to increased overnight accommodations in the park and in local communities.

Concessioner

Analysis

Continuation of current policies regarding user capacity within the Merced River corridor would not substantively change the services and facilities operated by the primary park concessioner. Increases in future visitor populations would result in a local, long-term, negligible to minor, benefit to the concessioner.

Summary of Alternative 1 Impacts. Under Alternative 1, accommodations and facilities in the park would be maintained at their current levels. Increases in future visitor populations would result in a local, long-term, negligible to minor, benefit to the concessioner.

Cumulative Impacts

Cumulative impacts to concessioner operations are based on analysis of past, present, and reasonably foreseeable future actions in the Yosemite region in combination with potential effects of this alternative.

Past Actions. The Yosemite Valley Plan, completed in 2000, provides for a reduction in overnight accommodations in Yosemite Valley and relocation of some employee housing to areas outside of the Valley, which would result in a local, long-term, adverse impact on concessioner operations.

Present Actions. The Curry Village Employee Housing project will provide safe and efficient housing for some concessioner employees currently housed in temporary housing in the Valley. This would result in a local, long-term, beneficial effect on concessioner operations.

Reasonably Foreseeable Future Actions. Reasonably foreseeable future actions proposed in the region that could affect concessioner operations are separated below into two general categories: (1) projects anticipated to have a net beneficial effect; and (2) projects anticipated to have a net adverse effect.

Reasonably foreseeable future projects that could have a cumulative, beneficial effect on concessioner operations include:

·       Curry Village and East Yosemite Valley Campgrounds Improvements

·       Yosemite Lodge Area Redevelopment

These projects will add some overnight accommodations in the Valley and result in more visitor spending, resulting in a long-term benefit on concessioner operations.

A reasonably foreseeable future project that could adversely affect the concessioner is the update to the Yosemite Wilderness Management Plan. New policies adopted in this plan could restrict or reduce facilities and/or activities in the wilderness, including concessioner run facilities, resulting in a potential loss of revenues to the concessioner.

The cumulative projects would have a local, long-term, minor to moderate, adverse impact on the primary park concessioner associated with locating new employee housing outside of the Valley and possible restrictions or reductions in wilderness facilities or activities. The adverse effect would be partially offset by increased accommodations being developed in Curry Village and at Yosemite Lodge. The impact intensity of any planning projects would depend on the extent to which the Yosemite Valley Plan's recommendations are implemented.

Overall, Alternative 1 and the cumulative projects within and in the vicinity of Yosemite National Park would result in a long-term, minor to moderate, cumulative adverse impact on the concessioner associated with locating new employee housing outside of the Valley and possible future restrictions in wilderness areas.

Park Operations and Facilities

Analysis

The following discussion provides an overview of the types of impacts to park operations, infrastructure, facilities, and energy consumption that could occur within each segment of the Merced River corridor under Alternative 1. Under Alternative 1, park management would continue to protect and enhance the ORVs of the Merced River through implementation of the Merced River Plan and other existing park management policies.

Park Operations

Impacts in Wilderness. Park operations in the Wilderness segments include (1) visitor protection personnel (backcountry patrol rangers and Little Yosemite Valley campground rangers); (2) National Park Service and concessioner stock operations personnel that support trail maintenance, forestry management, and the Merced Lake High Sierra Camp; (3) facilities maintenance personnel that perform trail repair and construction and campground maintenance; and (4) resources management and science personnel that monitor impacts to river-related ORVs.

User capacity within the Wilderness segments is currently addressed through the existing trailhead quota system and monitoring of wilderness resource conditions under WIMS. Under Alternative 1, the trailhead quota system would continue to be implemented. The trailhead quota system has been in place for more than 25 years and is currently operating below capacity. Until capacity is reached, it is expected that any increase in visitor use could be accommodated without increasing park staff, ranger patrols, or related wilderness activities (such as periodic restoration in some areas and continued implementation of WIMS). Therefore, Alternative 1 would likely have a negligible effect on park operations in the Wilderness segments of the Merced River corridor.

Impacts in Yosemite Valley. Park operations in Yosemite Valley include (1) visitor protection and law enforcement personnel (enforcement patrol rangers, mounted-horse patrol rangers, traffic management, emergency medical response, structural and wildland fire protection, and resource protection); (2) National Park Service and concessioner stock operations personnel in two stables and tack storage areas; (3) administrative management personnel (Superintendent's Office); (4) facilities maintenance personnel that perform water and electric utility systems maintenance, road and trail repair and construction, campground maintenance, and employee and administrative buildings and grounds maintenance; (5) resources management and science personnel that perform ecological restoration project implementation, wildlife management, and monitoring of impacts to river-related ORVs; (6) business and revenue management personnel; and (7) interpretation personnel at the Yosemite Valley Visitor Center and Museum, the Nature Center at Happy Isles, and the park media relations office and field operations (such as evening programs and ranger-led walks).

Visitor capacity in the Valley is not actively managed on a daily basis, but is controlled through facility capacities, primarily related to overnight accommodations and available parking. Current management practices sometimes result in heavy traffic congestion on peak summer weekends and holidays, when parking facilities can reach capacity. Park management occasionally restricts access to the Valley, and park personnel are required to manage traffic along roads and at key intersections and to assist with parking during periods of peak use. In addition, heavy traffic congestion has at times impeded emergency vehicle access, which in turn adversely affects visitor safety.

Under Alternative 1, heavy traffic congestion during periods of peak visitation would continue to require park personnel to manage traffic flow and assist with visitor parking, resulting in minor to moderate, adverse impacts to park operations and visitor safety during periods of high visitor use.

Impacts in the Gorge. Park operations in the Gorge segment include (1) visitor protection personnel (law enforcement patrol rangers, emergency medical response, structural and wildland fire protection, and resources protection); (2) facilities maintenance personnel that perform water and electric utility systems maintenance, road repair and construction, picnic area maintenance, and employee and administrative buildings and grounds maintenance; (3) resources management and science