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 five Merced River Plan/FEIS 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.

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 developments or other actions are proposed as a result of the Merced River Plan/FEIS, National Park Service staff will determine whether more detailed environmental documentation is required, consistent with the provisions of NEPA.

Following this introduction, the chapter 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 then applied to Alternatives 2, 3, 4, and 5 in subsequent sections. Environmental impacts are summarized in (see table II-9: Impact Summary Table, located at the end of Chapter II of this document.

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

To determine potential cumulative impacts, projects within the region surrounding Yosemite National Park were identified. The region, or assessment area, included eight surrounding counties (Mariposa, Madera, Fresno, Merced, Stanislaus, Tuolumne, Inyo, and Mono), four national forests (Sierra, Stanislaus, Inyo, and Toiyabe), nearby lands administered by the Bureau of Land Management, and lands administered by the National Park Service within Yosemite National Park and the El Portal Administrative Site. Projects occurring within the jurisdictional areas of five city governments in the region (Oakdale, Fresno, Merced, Modesto, and San Francisco . Hetch Hetchy Water and Power) and two private organizations (Pacific Bell and Pacific Gas & Electric Company) also were identified. Projects were identified through correspondence and phone calls with county and city governments and federal land managers. Potential projects, identified as "cumulative actions," included any planning or development activity that was currently being implemented or would be implemented in the reasonably foreseeable future.

Appendix G contains the list of reasonably foreseeable future 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 if they have any additive effects on a particular natural, cultural, or social resource. Because most of these cumulative actions are in the early planning stages, the evaluation of cumulative impacts was based on a general description of the project. Past actions were not included in the cumulative actions list, because many of these actions are already described in the Affected Environment, Chapter III, and in other locations in the document.

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:

Each resource topic area includes a discussion of the impact assessment, and the 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 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.

Pursuant to NEPA requirements, the impact analyses for Alternative 1 (the No Action Alternative) compare resource conditions under Alternative 1 in the year 2020 to existing conditions in the year 1999. The impact analyses for the action alternatives (which collectively refers to Alternative 2, Alternative 3, Alternative 4, and Alternative 5) compare the action alternative in the year 2020 to the No Action Alternative in the year 2020.

It is assumed that annual park visitation would increase over 1999 levels by the year 2020. Although it is not known how much annual visitation would increase by 2020, the Restricted Access Plan would continue to be implemented to manage Yosemite Valley visitation. Increased visitation demand (over 1999 levels) would trigger the need to implement the Restricted Access Plan 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 currently experienced. It is expected that increases in 2020 visitation levels would occur primarily during the current nonpeak periods (e.g., during months on either side of peak summer months, and on weekdays during peak summer months).

In 2020, annual visitation demand is assumed to be the same among all of the alternatives. Accommodation of annual visitation demand would be the same among all of the alternatives, except Alternative 4. Under Alternative 4, application of the management zoning prescriptions in the quarter-mile Merced River corridor boundary would limit the availability of space in Yosemite Valley for concentrated areas of day-visitor parking, park accommodations, and high-intensity visitor recreation areas. As a result, it is assumed that annual visitation demand would not be accommodated in the Valley under Alternative 4, and some visitors could be displaced to other areas of the park or displaced from the park itself.

The Merced River Plan is a prescriptive plan. It prescribes management zones within the Merced River corridor that provide guidance for park management on how to manage the resources within the corridor. However, the plan does not recommend implementation of specific developments or actions. The Merced River Plan is a management plan, and not an action or implementation plan. To provide decision makers and the public with an accurate idea of the environmental consequences of the Merced River Plan/FEIS alternatives, the analysis team identified potential actions that could result from the application of the management zoning prescriptions 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.

Natural Resources

Geology, Geohazards, and Soils

This impact assessment focused on effects that geologic processes in the Yosemite National Park would have on visitors, personnel, and facilities under each alternative of the Merced River Plan/FEIS. Geologic processes can negatively affect visitors, personnel, 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 what effect the Merced River Plan/FEIS alternatives would have on the geologic processes, namely the formation and conservation of soil resources. Development actions prescribed in the Merced River Plan/FEIS could affect the 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 park, especially the 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 will allow natural processes to occur unimpeded.

• The National Park Service is currently revising its management policies pertaining to geologic resources and hazards. The focus of these guidelines will be 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 prescriptive nature of the Merced River 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 the Merced River Plan/FEIS to reduce the intensity of adverse effects.

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. Proposed management prescriptions under the Merced River Plan/FEIS 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 Yosemite Valley, Wawona, or 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 would have no discernible effect on public safety or soil resources. 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 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 in areas susceptible to geologic hazards may decrease the risks but would not necessarily reduce the intensity of the impact.

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 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.

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 of the Merced River Plan. Quantitative analyses of any potential changes to the Merced River were not feasible due to the prescriptive nature of the Merced River 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 III, Affected Environment.

The analysis examined potential changes to the free-flowing nature of the river as a result of management zone prescriptions 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 bridges.

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.

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.

Proposed management prescriptions under the Merced River Plan/FEIS 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 to the allowance of certain park operations, such as removal of bridges or construction of facilities. Regional impacts would be impacts on the 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 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.

NEPA calls for an examination of the impacts on all components of affected ecosystems. 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 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 (including the river's Outstandingly Remarkable Values). A second level of impact assessment must address issues and concerns expressed during public scoping. The third, and probably most important, level compares a projected impact with the natural history of a species or the known sensitivities of a habitat.

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 the Merced River Plan is prescriptive rather than action-specific. 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 Merced River Plan to reduce the adverse effects of impacts to natural resources.

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. Analysis 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 exotic species 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 negative impacts (e.g., smoke from prescribed burning) but over time can successfully replicate natural processes.

Proposed management prescriptions under the Merced River Plan/FEIS 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 would have 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 would be associated with transitional types of impacts, such as facility construction or bridge removal. Long-term impacts are somewhat more conjectural. For example, research on National Park Service lands has documented long-term declines in bird species diversity at heavily used sites. Such a decline 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.

The air quality impact assessment involved the identification and qualitative description of the types of actions under the Merced River Plan/FEIS 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, as summarized below:

• The Merced River Plan would not affect the smoke management policies in the Fire Management Plan.

• The Merced River Plan would not affect the campfire regulations in the Valley.

• The Merced River Plan would not affect the policies of the Restricted Access Plan.

• 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 general conformity rule for any future actions under the Merced River Plan that would occur within Madera County, which is part of San Joaquin Valley Air Basin, a nonattainment area for national ozone and PM-10 standards, and within Mariposa County, which is likely to be designated in the near future as a nonattainment area for the new national eight-hour ozone standard.

Quantitative analysis of potential air quality impacts was not feasible due to the prescriptive nature of the Merced River 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 Merced River Plan/FEIS to reduce the intensity of adverse effects.

Relative to the No Action Alternative, the Merced River Plan/FEIS would change corridor boundaries and Outstandingly Remarkable Values along segments of the main stem and South Fork of the Merced River and would impose management zoning prescriptions. The air quality impact assessment of the plan evaluated how these three basic 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 Yosemite Valley, Wawona, or 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 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.

The noise impact assessment involved the identification and qualitative description of the types of actions under the Merced River Plan/FEIS 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 Outstandingly Remarkable Value. 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.

Several assumptions were integrated into this assessment, as summarized below:

• The Merced River Plan would not affect the wilderness permit system arising from the Wilderness Management Plan.

• The Merced River Plan would not affect the policies of the Restricted Access Plan.

Quantitative analysis of potential noise impacts was not feasible due to the prescriptive nature of the Merced River 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 Merced River Plan to reduce the intensity of adverse effects.

Relative to the No Action Alternative, the Merced River Plan/FEIS would change corridor boundaries and Outstandingly Remarkable Values along segments of the main stem and South Fork of the Merced River and would impose management zoning prescriptions. 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 the 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 Yosemite Valley, Wawona, or 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 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. A long-term impact would have a permanent effect on the ambient noise environment.

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.

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 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 May 14, 1999 Programmatic Agreement (see Appendix H). This includes: (1) identifying areas that could be impacted; (2) assessing the level of resource information available, and conducting appropriate inventories 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 of Historic Places; (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, reduce or mitigate adverse effects.

Cultural resource impact analysis in this environmental impact statement is described in terminology consistent with the regulations of the Council on Environmental Quality (CEQ). CEQ regulations require that the impacts of alternatives and their component actions be disclosed. It is intended, however, to comply with the requirements of both the National Environmental Policy Act (NEPA) and Section 106 of the National Historic Preservation Act (NHPA). 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 NHPA; wherein NHPA requires determinations of no effect or effect, and further requires where there is a determination of effect, a determination of whether that effect is adverse or not adverse. Intensity of impacts in the cultural resource analysis then, for purposes of NEPA, is defined as:

Archeological resources are typically considered eligible for inclusion in the National Register of Historic Places 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/ degradation.

Ethnographic 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 criteria for evaluation and integrity. Intensity of impacts to ethnographic resources may relate to access and use of, as well as changes to, traditionally important places.

CEQ 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. Although adverse effects under Section 106 may be mitigated, for example, the effect remains adverse.

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 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 or avoidance of adverse 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 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, architectural elements and objects may be salvaged for reuse in rehabilitating similar structures or added to the park's museum collection. 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, impacts to 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 remain in effect.

The National Park Service would continue to consult with culturally associated 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 ethnographic 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.

This impacts analysis evaluated four separate aspects of visitor experience, including recreation, interpretation and orientation, 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 management zone prescriptions in the alternatives.

Visitor experience in Yosemite National Park encompasses a broad spectrum of elements, including access to and availability of recreational opportunities, interpretation and orientation programs, various visitor services, and to the Yosemite Wilderness. In addition, every individual visitor to Yosemite brings unique expectations and thus each has a unique experience. As a result, the environmental impact statement identifies, where possible, how the quality of the experience would change given application of the management zoning prescriptions in each of the action alternatives.

Developing a quantitative analysis of potential effects on visitor experience is not feasible due to the prescriptive nature of the Merced River 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.

Assumptions that framed the analysis included the following:

• Visitor demand will increase over 1999 levels and will be the same among all of the alternatives.

• There would be no fundamental change to visitor access by private vehicle to the park.

• All lodging and camping facilities damaged and removed due to the 1997 flood would not be replaced in situ.

• There would be no change in access to the Yosemite Wilderness areas and no change to the wilderness permit system.

• Stock use would continue as currently managed.

• A diverse range of recreational activities is desirable.

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 the management zone prescriptions would interact with all independent and group opportunities available in all segments of the Merced River, including the Valley, the Yosemite Wilderness, and in Wawona, such as floating, swimming and wading, hiking, backpacking, camping, rock climbing, fishing, sightseeing, photography, nature study, bicycling, and stock use.

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 the management zoning prescriptions under the alternatives.

The analysis identified visitor services provided by the National Park Service, and the park partners, including the primary park concessioner that would be inconsistent with the management zone prescriptions under the alternatives. 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.

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

The assessment focused on the context, intensity, and duration of impacts that would result from the proposed management prescriptions under the Merced River Plan/FEIS, relative to the four different 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. The change in the characteristics or the quality of the experience was not considered in determining the intensity of an impact. This discussion was provided for contextual purposes only, to facilitate reader understanding of the implications of an impact.

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 Yosemite Valley, Wawona, or the El Portal Administrative Site. Regional impacts would be impacts on the affected region, which is defined in Chapter III, Affected Environment.

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.

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 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.

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.

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.

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. Though the National Park Service applies management zoning in 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. The Merced River Plan addresses only the management of lands within Yosemite National Park and the El Portal Administrative Site, and the basic designation of land use for the park, as defined by NEPA, will not change as a result of implementing any alternative of the Merced River Plan.

Proposed management prescriptions under the Merced River Plan/FEIS 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 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 not 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.

The focus of this impact assessment was on the effect of changes in overnight accommodation facilities (campgrounds and lodging), parking spaces, and alternative transportation systems (shuttle and regional transit buses) on traffic volumes and associated traffic flow and safety conditions. It was assumed that current alternative transportation services (regional public transit, shuttle buses, Valley floor tours, etc.) would remain essentially unchanged as a result of the Merced River Plan. Given the prescriptive nature of the Merced River Plan, it was assumed that the plan would not result in any substantial, quantifiable construction activity. It was also assumed that the Restricted Access Plan would continue to be used 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 prescriptive nature of the Merced River 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 Merced River Plan/FEIS to reduce the intensity of adverse effects.

This section assessed potential changes in traffic volumes associated with changes to in-park visitor accommodations and/or parking facilities that could result from the application of the management zones under each of the action alternatives. 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.

This section assessed potential changes in parking facilities (location and number of parking spaces) that could result from the application of the management zones. 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.

Proposed management zones under the Merced River Plan/FEIS 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 and/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 impacts specific to Yosemite Valley, Wawona, or 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 would have no discernible effect on traffic flow and/or traffic safety conditions. Minor impacts were effects on traffic flow and/or traffic safety conditions 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 on traffic flow and/or traffic safety conditions. Major impacts would have a substantial, highly noticeable influence on traffic flow and/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 and/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.

The scenic resources analysis assumes that any policy change or action resulting from the Merced River Plan would conform with the National Park Service 1916 Organic Act.

For the purposes of this analysis, the Merced River Plan is assumed to have an impact (negative or beneficial) on scenic resources if it:

• Introduces into or removes from the visual landscape any human-made structure or infrastructure, as it is viewed from within the Merced River corridor

• Substantially changes the quality of the visual landscape, whether foreground, middle ground, or background

• Affects 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.

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 the Merced River Plan 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 Merced River Plan and associated 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 actions that may result from the Merced River Plan 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 sequence of viewpoints; or (c) change the visibility of an viewpoint or 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 would be 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.

The impacts analysis evaluated four separate socioeconomic areas, including the social environment, visitor populations, regional economy, and the impacts to 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 that may wish to lodge overnight in the region (as local overnighters) may be displaced to day excursion visitors 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.

Camping facilities are among the in-park accommodations that could be displaced under the action alternatives. Because camping facilities cannot be substantially expanded in the affected region (Madera, Mariposa, Merced, Mono, and Tuolumne Counties), it is assumed that visitors displaced from camping in the park may not find camping accommodations in the affected region and may decide not to visit the park. It is assumed that these displaced visitors could be replaced by those preferring to lodge in a hotel in the affected region, or some displaced campers may select to lodge in the region rather than camp.

Quantitative analysis of potential effects on socioeconomic conditions was not feasible due to the prescriptive nature of the Merced River 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 (see discussion under Impact Assessment, below). When possible, mitigation measure(s) were incorporated into the Merced River Plan/FEIS to reduce the adverse effects of socioeconomic impacts.

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 application of the management zone prescriptions under each of the action alternatives.

The analysis identified potential changes in park visitor accommodations that could result from the application of the management zone prescriptions and assumed implementation of these changes. This section described changes in the composition of Yosemite visitors (e.g., park overnighters, local overnighters, and day excursion visitors) and qualitatively addressed potential changes in visitor spending. This section also identifies impacts to low-income park visitors associated with changes in availability of low-cost recreation activities and low-cost park accommodations.

This section qualitatively analyzed the impacts of changes in visitor spending and shifts in employment associated with the potential removal of 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.

The analysis identified facilities operated by the primary park concessioner that would be inconsistent with the management zone prescriptions under each of the action alternatives. The analysis assumed that these facilities could be removed, and analyzed the impact on concession revenues.

Proposed management prescriptions under the Merced River Plan/FEIS 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 impacts specific to Yosemite Valley, Wawona, or El Portal. Regional impacts would be impacts on the affected region, which is defined in Chapter III, 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 would have no discernible effect on the socioeconomic environment. Minor impacts were effects on the socioeconomic environment that would be slightly detectable but not 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.

Impacts of the Merced River Plan and associated actions on and from park operations 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 impacts on 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

Proposed management prescriptions under the Merced River Plan/FEIS 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 impacts specific to Yosemite Valley, Wawona, or 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 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 not 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

Alternative 1, the No Action Alternative, represents the current management direction for the Merced River corridor. It is based on the boundaries (see figures II-7 through II-10 in Chapter II, Alternatives), classifications (see figure II-3), and Outstandingly Remarkable Values (see Appendix E) for the Merced River corridor that are currently in place, as published in the 1996 Draft Yosemite Valley Housing Plan. The No Action Alternative would not apply a consistent set of decision-making criteria and considerations, which are composed of seven management elements: boundaries, classifications, updated Outstandingly Remarkable Values, the Section 7 determination process, management zoning, the River Protection Overlay, and the VERP framework.

Natural Resources

Geology, Geohazards, and Soils

Analysis

General Impacts. The following discussion provides an overview of the types of geologic impacts that could occur within the Merced River corridor from application of Alternative 1.

Rockfall Hazards. Under Alternative 1, the potential for adverse impacts to visitors and park facilities from unstable rock slopes, seismic events, and soil erosion would not change. 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. Rockfalls can be expected throughout Yosemite National Park in any area that has steep rock cliffs. Along the Merced River, rockfalls can occur in the upper wilderness reaches, along the edges of Yosemite Valley, within the Merced River 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. Any 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 Yosemite Valley, the Merced River gorge along El Portal Road, El Portal Administration Site, and possibly in Wawona. Although rockfalls do occur throughout Yosemite National Park, their risk to visitors and facilities is considered low in the less-traveled and undeveloped wilderness areas. Facilities located within proximity to the talus zone or within the rockfall shadow zone are most susceptible to damage from rockfalls. Rockfall frequency 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 (Wieczorek, et al. 1998).

Seismic Hazards. Historically, seismic events in the Sierra Nevada and Yosemite National Park have been relatively infrequent; however, when they do occur, the resultant groundshaking is capable of triggering rockfalls and producing ground accelerations that are higher than some older, less structurally stable buildings can tolerate. Typically, the seismic risks of injury to visitors and damage to facilities would occur in the developed portions of Yosemite National Park, such as Yosemite Valley, El Portal, and Wawona. In these areas, buildings and other facilities placed within saturated alluvial soil (for instance, within the floodplain of the Merced River) could also be susceptible to secondary hazards from seismic groundshaking, including liquefaction and seismically induced settlement. Earthquakes in the Sierra Nevada region would continue to expose visitors to injury in unstable buildings or to hazards caused by seismically triggered mass movement from rock slopes. In the upper wilderness reaches of the Merced River, Yosemite Valley, the Merced River gorge, and along the river canyons of the South Fork, earthquakes could trigger rockfalls and subject the area to seismic shaking. In Yosemite Valley and in Wawona on the South Fork, seismic shaking could also be responsible for instability of certain alluvial soils. Buildings and other facilities placed within saturated alluvial soil would continue to be susceptible to secondary hazards from seismic shaking, including liquefaction and seismically induced settlement. Emergency preparedness systems developed to respond to natural disasters within areas of heavy visitor use would remain in place.

Impacts to Soils. Possible projects to accommodate increased visitor use in development zones could result in increased soil compaction, soil loss, and erosion. Compaction of native soils can occur through construction activity, concentrated visitor use in localized areas, or excessive vehicular traffic in unpaved areas. Construction excavation and replacement of native soils with engineered fills contribute to the reduction of local native soil. Excessive surface water runoff or loss of protective vegetation cover can cause erosion. Facilities placed in areas susceptible to damage from erosion and settlement would remain in their current locations. 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. Construction and maintenance projects in the Merced River corridor would continue to occur and result in soil removal and soil matrix mixing. Fluvial mechanics resulting in bank erosion and loss of bank soil would also continue.

Under Alternative 1, the National Park Service could retain (and revise) current management policies pertaining to geologic resources and hazards. Policies include those implemented to protect visitors and reduce damage to park infrastructure. Although it is currently park policy to allow natural geologic processes to proceed unimpeded, the National Park Service, in cooperation with the U.S. Geological Survey, would continue to address geohazards in its planning and management activities to minimize the potential impact on park visitors and facilities. The National Park Service would continue the practice of conducting site-specific geologic analyses prior to the construction of buildings and other facilities to determine potential soil instability. Although rockfalls and earthquakes are unavoidable, and rockfalls are not always predictable in many locations within Yosemite National Park, the National Park Service would continue to avoid locating facilities in areas where current studies indicate such facilities could be affected by geologic events.

Summary of Alternative 1 Impacts. Considering the unpredictable and unavoidable nature of rockfalls and earthquakes and the history of their occurrence, there would be long-term, adverse impacts on public safety from geohazards. Continued development under Alternative 1 would result in a long-term, adverse impact on soil resources, as future projects and visitor use would result in further compaction, soil removal, and erosion.

Cumulative Impacts

Cumulative impacts to geological resources discussed herein 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 geological resources within the river corridor or in the park vicinity.

Various reasonably foreseeable future actions could eventually result in construction of additional structures and facilities within zones susceptible to adverse impacts from earthquakes and rockfall. These facilities would likely be located in developed areas, including Yosemite Valley, the El Portal Administrative Site, and Wawona.

Past Actions. Development projects intended to serve park visitors in Yosemite National Park have included hotels, visitor centers, campgrounds, and bridges with associated roads and parking lots. In addition, facilities required for park infrastructure support, including employee housing, utility facilities, maintenance yards, and supply storage areas, have been developed throughout the park. As popularity of Yosemite attracted a greater number of visitors, the number and magnitude of these projects increased to meet visitor demand. Past actions have resulted in adverse impacts because projects were developed in areas that could be susceptible to damage from geohazards (rockfalls and seismic events), and facility development has contributed to the overall degradation of soil resources in the park.

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 non-motorized 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).

Present Actions. The El Portal Road Reconstruction Project (NPS) is currently underway and affects geology, geohazards, and soils. The reconstruction requires steepening the sheer rock slopes along the north side of the roadway, which increases the potential for rockfalls over the short term (stability of the rock slopes). However, under the direction of engineers, design features for rock cuts along the El Portal Road (e.g., rock-bolting using 30-foot-long dowells) serve to increase the long-term stability of the rock slopes. These design features are also used to stabilize colluvial soil cuts, thereby reducing erosion. On the south side of the El Portal Road, shoulder widening requires construction of a fill slope that, in certain areas, encroaches into the Merced River. These effects are partially mitigated by implementation of standard design and construction-related best management practices. The project also involves rehabilitation of the sewerline which reduces potential soil contamination, and the improvement of roadway drainage, thereby reducing erosion. The encroachment of the fill slope into the Merced River would cause minor obstruction to the free-flowing condition of the river. Overall, the El Portal Road Reconstruction (Segment D) Project would have a beneficial impact by reducing rockfall and soil erosion potential.

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 geohazards and soil resources include:

• Several campground rehabilitation projects, such as at Bridalveil Horse Camp, Yosemite Creek Campground, Tamarack Campground Hodgdon Meadow Campground (NPS)

• The Merced River at Eagle Creek Ecological Restoration Project (NPS)

• Update to the Yosemite Fire Management Plan (NPS), which has a goal of improving ecosystem health and meadow restoration

• Update to the Yosemite Wilderness Management Plan (NPS), which will address land management issues within the wilderness

• Fire Management Action Plan for Wilderness (USFS, Stanislaus)

• The Sierra Nevada Framework for Conservation and Collaboration, and the Management Direction for the John Muir, Ansel Adams and Dinkey Lakes, and Monarch Wildernesses (USFS), both of which will address ecosystem management issues of Forest Service lands adjacent to Yosemite National Park

• The Pinecrest Basin Forest Plan Amendment (USFS, Stanislaus)

• Transportation-related projects (e.g., Yosemite Area Regional Transportation System [YARTS]), which have the general goals of increasing transportation options and reducing reliance on automobiles in the area

Although each of the aforementioned projects may have slight site-specific and short-term adverse effects (e.g., potential short-term construction erosion and soil loss), an objective of each of these projects is to restore and manage natural resources and reduce soil degradation. Therefore, these projects could have a net long-term, beneficial, cumulative impact on soil resources.

Reasonably foreseeable projects that could have both adverse and beneficial effects on regional geology, geohazards, and soils include:

• The Tuolumne Meadows Development Concept Plan, and Tuolumne Wild and Scenic River Management Plan (NPS)

• The Tuolumne Meadows Water and Wastewater Improvements, Hodgdon Meadow Water and Wastewater Treatment Improvements, and White Wolf Water System Improvements (NPS)

• The Orange Crush Fuels Treatment Projects (USFS, Stanislaus)

• A-Rock Reforestation (USFS, Stanislaus) and the Rogge-Ackerson Fire Reforestation (Tuolumne Co.)

• The Yosemite Valley Plan (NPS), which would implement the goals and actions of the 1980 General Management Plan (NPS)

• South Entrance/Mariposa Grove Site Planning (NPS)

• Wawona Campground Improvement (NPS)

• Wilderness Boundary Protection Land Exchange, Seventh Day Adventist Camp, Wawona (NPS)

• Several water improvement projects, such as the Tuolumne Meadows Water and Wastewater Improvements, Replacement/Rehabilitation of Yosemite Valley Sewer Line (NPS); Cherry Dam Fuse Gate, O'Shaughnessy Dam Well, and O'Shaughnessy Compound Water System Improvements (City and Co. of San Francisco)

Cumulative effects of the above-referenced projects could be a combination of adverse and beneficial effects. For example, implementation of the Yosemite Valley Plan is expected to have a long-term benefit on soil resources by increasing coordinated management of natural resources. However, short-term, adverse effects of this plan may include temporary construction impacts (e.g., potential reconstruction of Segment D of the El Portal Road Reconstruction Project above Cascades Diversion Dam). The current approach for the Segment D widening would require redesign. Segment D reconstruction could cause similar types of impacts to those occurring during reconstruction of Segments A, B, and C of El Portal Road (e.g., steepening of sheer rock slopes, potentially leading to short-term slope instability, and traffic circulation, safety, and noise impacts). The net effect of these projects is difficult to anticipate, but would likely result in an overall balance between beneficial and adverse effects.

Reasonably foreseeable projects that could have an adverse effect on regional geology, increase the potential for impacts related to geologic hazards, and increase soil degradation include:

• Merced River Canyon Trail Acquisition (BLM)

• Various development-related projects, such as the Yosemite View parcel land exchange, El Portal (NPS); Rio Mesa Area Plan (Madera Co.); Yosemite Motels, El Portal (Mariposa Co.); Silvertip Resort Village Project (Mariposa Co.); University of California, Merced Campus (Merced Co.); Build Out City of Merced, General Plan; Double Eagle Resort, June Lake (Mono Co.); Tioga Inn, Lee Vining (Mono Co.); June Lake Highlands (Mono Co.); Evergreen Lodge Expansion (Tuolumne Co.); Hardin Flat Lodging and Conference Facility (Tuolumne Co.); Motel and Restaurant, Second Garrotte Basin (Tuolumne Co.); Resources Management Building (NPS); Crane Flat Campus Redevelopment (NPS, YNI); Hazel Green Ranch (Mariposa Co.)

• Transportation projects, such as the Highway 41 Extension (Madera Co.); Yosemite Valley Shuttle Bus Stop Improvements (NPS); South Fork Merced River Bridge Replacement (NPS); Road Realignment and Bridge Replacement of Highway 49 and Old Highway (Mariposa Co.); Expansion of County Transit System; Mariposa Creek Pedestrian/Bike Path (Mariposa Co.); Evergreen Road Improvements (multi-agency, see Appendix G); San Joaquin Corridor Rail Projects (DOT, Amtrak).

Certain development projects, as listed above, could expose additional visitors to risk of rockfall and seismic hazards and result in increased degradation of soil resources. Examples of projects that would result in a cumulative increase in park development include the construction of South Entrance/Mariposa Grove Site Planning (NPS), a new Resources Management Building (NPS), Yosemite West Rezoning Application (NPS), Yosemite Motels, El Portal (Mariposa Co.), Crane Flat Campus Redevelopment (NPS, YNI); Hazel Green Ranch (Mariposa Co.), and the El Portal Road Reconstruction Project (NPS).

Given that hazards related to geologic processes are unavoidable and unpredictable, park visitors would continue to be exposed to injury and damage from earthquakes and rockfalls. This would result in a cumulative, long-term, adverse impact to public safety. The cumulative effect of future development actions under Alternative 1 would be to increase the overall depletion of soil resources by increasing soil removal, compaction, and erosion. Restoration projects could offset the rate of overall soil resource depletion, but not to the extent of providing a cumulative benefit. Future development projects would result in a cumulative, long-term, adverse impact on soil resources.

Rockfall hazards under Alternative 1 and the cumulative projects would result in a long-term, adverse impact to public safety throughout Yosemite National Park because, although some localized projects may reduce these risks, continued development under Alternative 1 could locate facilities in areas susceptible to rockfalls. Earthquakes are unavoidable and unpredictable, and park visitors would continue to be exposed to potential injury and damage; therefore, Alternative 1 and the cumulative projects would have no impact on public safety with respect to seismic hazards. Impacts on soil resources under the cumulative projects would be long term and adverse. Overall, Alternative 1 and the cumulative projects would have a long-term, adverse impact on public safety from rockfalls and earthquakes and a long-term, adverse impact on soil resources.

Considering the unpredictable and unavoidable nature of rockfalls and earthquakes and the history of their occurrence, there would be a long-term, adverse impact on public safety from geohazards. Continued development under Alternative 1 would result in a long-term, adverse impact on soil resources, as future projects and visitor use would result in further compaction, erosion, and soil removal.

Rockfall hazards under Alternative 1 and the cumulative projects would result in a long-term, adverse impact to public safety throughout Yosemite National Park because, although some localized projects may reduce these risks, continued development under Alternative 1 could locate facilities in areas susceptible to rockfalls. Earthquakes are unavoidable and unpredictable, and park visitors would continue to be exposed to potential injury and damage; therefore, Alternative 1 and the cumulative projects would have no impact on public safety with respect to seismic hazards. Impacts on soil resources under the cumulative projects would be long term and adverse. Overall, Alternative 1 and the cumulative projects would have a long-term, adverse impact on public safety from rockfalls and earthquakes and a long-term, adverse impact on soil resources.

Hydrology, Floodplains, and Water Quality

Analysis

General Impacts. Under Alternative 1, hydrology, floodplain, and water quality conditions of the Merced River would remain as they are today, and future conditions would reflect current management practices and projected visitor levels. Degradation of free-flow river conditions, the adjacent floodplains, and overall water quality would continue.

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 from application of Alternative 1.

Impacts in Wilderness. Hydrologic-process Outstandingly Remarkable Values within wilderness segments of the main stem and South Fork of the Merced River include steep river gradients, glaciers, excellent water quality, logjams, and continual white-water cascades. Hydrologic processes of the wilderness reaches of the Merced River are generally intact, except where facilities exist and human 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). Under Alternative 1, use of these facilities could continue consistent with existing conditions. Hydrologic processes (e.g., water quality) would continue to be negatively affected by development and by human and stock use at these locations. Existing development would continue to adversely affect floodplain characteristics (e.g., water recharge rates, floodwater dissipation). Types of adverse effects associated with continued human and stock use include site-specific degradation of water quality (e.g., refuse, fecal coliform bacteria, human- and stock-induced erosion). Water quality is also positively affected by localizing facility- and use-related impacts and by providing toilets and other facilities designed to minimize adverse effects. Minor footbridges and other obstructions would continue to restrict the free-flow condition of the river and subsequently alter stream processes that define channel characteristics. These continued actions could have long-term, site-specific, adverse effects on wetland and riparian resources 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, while hydrologic processes throughout the river corridor would continue to benefit from concentration of these facility- and use-related effects. In all other areas of the wilderness reaches of the Merced River, continued use of existing facilities (e.g., trails) at a similar level of intensity is not expected to affect hydrologic processes.

Impacts in Yosemite Valley. Hydrologic-process Outstandingly Remarkable Values within Yosemite Valley include world-class waterfalls, the 100-year flood regime, oxbows, and Mirror Lake, an example of a transitory lake. Under Alternative 1, impacts on river characteristics (such as channel shape and sinuosity) stemming from inadequately designed bridges and development in the Merced River corridor would continue. Bridges and other obstructions would continue to restrict the free-flow condition of the river and subsequently alter stream processes that define channel characteristics. These impacts to the natural flow of the river are apparent all along the corridor. These obstructions contain the river in its existing channel within local reaches by restricting free-flow dynamics and the ability of the river to naturally discharge and dissipate channel-forming flows or flood flow. The streamflow would continue to be permanently altered and would adversely affect the Outstandingly Remarkable Values associated with the free-flowing nature of the river. This impact is expected to worsen over time, resulting in a minor to major (depending on site-specific conditions), long-term, adverse effect at various points along the river corridor.

The Merced River floodplain has been negatively affected by past development within the river corridor. Floodplain alterations are concentrated in areas, such as east Yosemite Valley. Structural and recreational development, resulting in impervious surfaces, creation of flow barriers, and loss of vegetative cover, have altered floodplain characteristics and the interaction between the floodplain and high flows of the river. Fill material and protective measures used to make areas within the floodplain more suitable for development have limited the geomorphic diversity and ability of the floodplain to dissipate energy during peak discharge flows. Under Alternative 1, the 100-year flood regime and floodplain formation and evolution, which are Outstandingly Remarkable Values of the river, would continue to be adversely altered.

Visitor use of the river corridor also would continue to have an impact on bank stability and floodplain areas, resulting in continued changes to channel and floodplain morphology. Visitor use would continue to affect the floodplain by compacting soils, reducing vegetative cover, altering streambanks, and inducing erosion. Modifications to the river channel and floodplain (through soil compaction, loss of riparian vegetation, and accelerated erosion) influence important stream characteristics such as riffle/pool complexes, substrate type, channel migration, and riparian cover. These physical aspects often determine the composition of vegetative and aquatic communities that compose the riparian corridor and floodplain. The continued use of streambanks and floodplains by park visitors would adversely affect floodplains in the Merced River corridor, especially in areas of concentrated use such as east Yosemite Valley. This effect would worsen over time as visitor use increases. This would constitute a long-term, adverse impact.

Roadways, structures, and visitor use areas would continue to be present in the floodplain and would be subject to flood hazards under Alternative 1. Executive Order 11988 on floodplain management and the Floodplain Management Guidelines 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. The Floodplain Management Guidelines require medical facilities, schools, and fuel storage areas to be placed outside the 500-year floodplain. Therefore, under Alternative 1, existing flood hazards could remain, whereas future flood hazards would be precluded or mitigated for potential facility construction in the floodplain.

Merced River water quality is degraded through the introduction of refuse, fecal coliform bacteria, and other human-associated pollutants from intensive visitor use of streambanks and the floodplain. Development and visitor impacts in riparian zones also 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. Intensive visitor use would continue to degrade the channel slopes and the riparian corridor, thereby increasing water temperatures and suspended sediment and reducing dissolved oxygen levels. Such changes to the physical characteristics of the river can be harmful to aquatic organisms, riparian vegetation, and water supply uses. These types of changes occur as the channel widens, flattens, and becomes shallower in reaction to the destabilization and degradation of streambanks caused by human activities. These activities are focused in developed and high-use areas, particularly in east Yosemite Valley. Intensive visitor use would continue the long-term degradation of Merced River water quality.

Roads, parking lots, and other impervious surfaces in or near the corridor would continue to release nonpoint-source pollutants into stormwater runoff that would subsequently discharge to the Merced River and its tributaries. These pollutants adversely affect the water quality of the Merced River. Impervious surfaces such as roads and parking lots accumulate automobile-related pollutants that are easily transported to adjacent or nearby water resources through stormwater runoff. Such surfaces also accumulate refuse and other pollutants discarded by park visitors that can be transported to nearby water resources. Roads, parking lots, and other impervious surfaces would continue the long-term degradation of Merced River water quality.

Maintenance associated with existing facilities within the Merced River corridor could result in localized, short-term adverse impacts on water quality by introducing construction-related pollutants (eroded soils, fuels, building materials). These pollutants could be transported to the river corridor through stormwater runoff. Implementation of current management practices would help reduce potential short-term impacts on water quality due to maintenance activities.

Impacts in the Merced River Gorge and El Portal. Facilities and visitor use in the majority of the Merced River gorge are minimal due to topography and access. Water quality and the hydrologic processes of the Merced River would continue to be affected by existing facilities, roads, pullouts, contaminated stormwater runoff, and riprap. Cascades Diversion Dam would continue to adversely affect the free flow of the Merced River (site-specific, major, long-term, and adverse). Roads, parking lots, and other impervious surfaces in or near the corridor could continue to release nonpoint-source pollutants into stormwater runoff that could subsequently discharge to the Merced River. Impervious surfaces accumulate automobile-related pollutants, refuse, and other nonspecific pollutants that are easily transported to adjacent or nearby wetland resources through stormwater runoff. These continued effects would be considered adverse and long term. A bulk storage facility for petroleum fuels and a gas station would continue to be located in El Portal, and the transportation of fuels would continue in the corridor. 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 operation and maintenance procedures. A release of fuel would constitute a short-term, adverse impact to water quality of the Merced River.

Hydrologic-process Outstandingly Remarkable Values in the Merced River gorge and El Portal include continuous rapids and the transition from a mature river in Yosemite Valley to a young river in the gorge. Alternative 1 would have no impact on these Outstandingly Remarkable Values.

Impacts in Wawona. Under Alternative 1, hydrology, floodplains, and water quality in Wawona could continue to be affected by facilities and visitor use. Existing development (e.g., Wawona Campground, the Wawona maintenance facility) would continue to adversely alter floodplain characteristics. The Wawona maintenance facility would continue to pose a threat to water quality of the South Fork (a hydrologic-process Outstandingly Remarkable Value). The risk of hazardous materials release would remain, but would be mitigated by compliance with standard regulatory requirements for the transportation and storage of such materials and normal park operation and maintenance procedures. A potential release of fuel or other hazardous material would constitute a short-term, adverse impact to water quality of the South Fork.

Under Alternative 1, impacts on river characteristics (such as channel shape and sinuosity) stemming from inadequately designed bridges and development would continue. Wawona Bridge and other obstructions would continue to restrict the free-flow condition of the river and subsequently alter stream processes that define channel characteristics. This impact is expected to worsen over time, resulting in a long-term, adverse effect at specific locations along the South Fork.

Visitor use would continue to degrade the channel slopes and the riparian corridor, thereby increasing water temperatures and suspended sediment and reducing dissolved oxygen levels. Such changes to the physical characteristics of the river can be harmful to aquatic organisms, riparian vegetation, and water supply uses. These types of changes occur as the channel widens, flattens, and becomes shallower in reaction to the destabilization and degradation of streambanks caused by human activities. These activities are focused in developed and high-use areas. Visitor use would continue the long-term degradation of South Fork water quality.

Summary of Alternative 1 Impacts. Development and visitor use in the Merced River corridor have affected water resources, the reliant biological communities, and the natural evolution of the river. Under Alternative 1, the continued and potentially worsening substantial alterations of streamflow and floodplains would be a long-term, adverse impact, and the continued degradation of water quality would be a long-term, adverse impact. These effects would be most pronounced in areas with concentrated facilities and visitor use (e.g., Yosemite Valley, El Portal, Wawona). National Park Service administrative requirements do afford some protection to the river from future actions, but no comprehensive or unified plan exists to protect the hydrology, floodplains, water quality, and related Outstandingly Remarkable Values of the Merced River.

Cumulative effects to hydrology discussed herein 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 effect the watershed of the Merced River.

Past Actions. The Merced River has been historically affected by a variety of projects that have introduced obstructions into the river channel, modified the floodplain, and adversely affected water quality. Alterations to hydrology have occurred through development and use within the Merced River corridor since Euro-American settlement. Examples of projects that have had adverse effects on the hydrologic processes of the Merced River include bridges, riprap, removal of large woody debris, dikes, flood walls, impoundments, dams, and buildings.

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 non-motorized 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).

Present Actions. The El Portal Road Reconstruction Project (NPS) is currently underway from the park boundary to the Cascades Diversion Dam, and affects the water quality of the Merced River immediately adjacent to the roadway. The free-flowing condition of the Merced River has been adversely altered by direct placement of fill and riprap to widen and stabilize the roadway. Natural resources are protected during construction by implementation of a compliance monitoring program, erosion and sediment controls, hazardous materials controls, revegetation and reclamation, and by excluding construction from sensitive habitats. Such measures ensure the overall protection and enhancement of the hydrologic, biological, geologic, cultural, scenic, scientific, and recreation Outstandingly Remarkable Values in the zone as a whole and in other parts of the river corridor. Implementation of these measures reduces the overall short-term effects on water quality.

Reasonably Foreseeable Future Actions. Reasonably foreseeable future actions proposed in the region are separated below into four general categories: (1) projects anticipated to have a net beneficial effect; (2) projects anticipated to have both beneficial and adverse effects; (3) projects anticipated to have a net adverse effect; and (4) projects that would not affect the hydrological processes of the Merced River.

Examples of projects that could have a cumulative, beneficial effect on hydrological processes in the Merced River include:

• The Merced River at Eagle Creek Ecological Restoration Project (NPS)

• Update to the Yosemite Wilderness Management Plan (NPS), which will address land management issues within the wilderness

• Several transportation-related projects (e.g., Yosemite Area Regional Transportation System [YARTS]), which have the general goals of increasing transportation options and reducing reliance on automobiles in the area

• Replacement/Rehabilitation of Yosemite Valley Sewer Line (NPS)

• South Fork Merced River Bridges Replacement (NPS)

Although each of the aforementioned projects may have slight site-specific and short-term adverse effects (e.g., construction-related effects on water quality), the general goal of these projects is to increase coordinated resource management and to restore sensitive ecosystems. Therefore, the net cumulative effect of these projects would be a long-term, beneficial impact on hydrological processes of the Merced River.

A reasonably foreseeable project that could have mixed adverse and beneficial effects on hydrological processes includes:

• The Yosemite Valley Plan (NPS)

• South Entrance/Mariposa Grove Site Planning (NPS), which will restore giant sequoia habitat in the Lower Mariposa Grove of Giant Sequoias in Yosemite National Park

Cumulative effects of these projects could be mixed, combining both adverse and beneficial effects. For example, implementation of the Yosemite Valley Plan has the potential to positively affect free flow of the Merced River by the proposed removal of the Cascades Diversion Dam. The Yosemite Valley Plan also has the potential to adversely affect water quality during construction activities related to Segment D of the El Portal Road Reconstruction Project (short-term), with the long-term, beneficial effect of improving water quality. Segment D reconstruction could cause similar types of impacts to those occurring during reconstruction of Segments A, B, and C of El Portal Road (e.g., effects to water quality). 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 Outstandingly Remarkable Values of the Merced River) and implementation of best management practices, compliance monitoring, and restoration.

Reasonably foreseeable projects that could have an adverse effect on hydrological processes include:

• The Yosemite View parcel land exchange, El Portal (NPS)

• Merced River Canyon Trail Acquisition (BLM)

• Yosemite Motels, El Portal (Mariposa Co.)

Cumulative effects of these potential future projects on the Merced River watershed would be related to increased use and facility development, which could result in streambank erosion, soil compaction, loss of vegetation, refuse accumulation, nonpoint-source pollution generation, and degradation of stream characteristics and water quality in the Merced River.

Beneficial cumulative impacts on the Merced River watershed would be related to removal of facilities from the floodplain, removal of channel obstructions, and reduced human-related effects. Cumulative adverse effects to the Merced River watershed would be related to increased use and facility development, which could result in streambank erosion, soil compaction, loss of vegetation, refuse accumulation, nonpoint-source pollution generation, and degradation of stream characteristics and water quality in the Merced River. Overall, the cumulative actions listed above would have a long-term, minor, beneficial effect on hydrologic processes of the Merced River. However, cumulative adverse effects associated with this alternative, in conjunction with other past, present, and reasonably foreseeable actions, could be long term and adverse.

Development and visitor use in the Merced River corridor have affected water resources, the reliant biological communities, and the natural evolution of the river. Under Alternative 1, the continued and potentially worsening substantial alterations of streamflow and floodplains would be a long-term, adverse impact, and the continued degradation of water quality would be a long-term, adverse impact. These effects would be most pronounced in areas with concentrated facilities and visitor use (e.g., Yosemite Valley, El Portal, Wawona). National Park Service administrative requirements do afford some protection to the river from future actions, but no comprehensive or unified plan exists to protect the hydrology, floodplains, water quality, and related Outstandingly Remarkable Values of the Merced River.

Beneficial cumulative impacts on the Merced River watershed would be related to removal of facilities from the floodplain, removal of channel obstructions, and reduced human-related effects. Cumulative adverse effects to the Merced River watershed would be related to increased use and facility development, which could result in streambank erosion, soil compaction, loss of vegetation, refuse accumulation, nonpoint-source pollution generation, and degradation of stream characteristics and water quality in the Merced River. Overall, the cumulative actions listed above would have a long-term, minor, beneficial effect on hydrologic processes of the Merced River. However, cumulative adverse effects associated with this alternative, in conjunction with other past, present, and reasonably foreseeable actions, could be long term and adverse.

Wetlands

Analysis

General Impacts. Wetlands and riparian areas are relatively rare in the context of the entire landscape. When wetlands are converted to systems that are intolerant of flooding (drained agricultural lands, filled developed lands), their storage capacity decreases and downstream flooding increases (National Academy Press 1993, as in NPS 1997g). Modification of even small wetland areas induces effects that are proportionally greater than elsewhere in an ecosystem (Graber 1996).

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 from application of Alternative 1.

Impacts in the Wilderness Segment of the Upper Main Stem Merced River. Wetland and aquatic habitats of the wilderness reaches of the main stem of the Merced River are 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). Under Alternative 1, use of these facilities would continue consistent with existing conditions. Wetland and aquatic habitats at these locations would continue to be negatively affected by existing development and by visitor and stock use. Existing development would adversely affect wetland and aquatic habitats, primarily through habitat fragmentation and the imposition of unnatural barriers to plant and wildlife movements (barriers in turn affect seed sources, nutrients, and plant distribution patterns). Types of adverse effects associated with continued visitor and stock use include site-specific degradation of water quality (e.g., refuse, fecal coliform bacteria, and other visitor- and stock-associated pollutants), potential introduction or spread of noxious weeds (primarily by stock), and grazing, trampling, compaction and erosion, which would result in the loss of natural structure, diversity, and productivity. Wetlands and aquatic habitats are also positively affected by localizing facility- and use-related impacts away from wetlands. These continued actions would have long-term, site-specific, adverse effects on wetland and riparian resources 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, while wetlands overall throughout the river corridor, would continue to benefit from concentration of these facility- and use-related effects. In all other areas of the wilderness reaches of the main stem of the Merced River, continued use of existing facilities (e.g., trails) at a similar level of intensity is not expected to affect wetland and aquatic communities. No specific wetland features of the wilderness reaches of the Merced River are identified as an Outstandingly Remarkable Value. Therefore, none would be affected by this alternative.

Impacts in Yosemite Valley. Under Alternative 1, size, structure, productivity, and continuity of wetland (within wetland and between wetland and riverine habitat) and aquatic habitats within Yosemite Valley would continue to be affected by existing facilities and visitor use.

Facilities such as roads, bridges, and ditches would continue to drain wet meadows, fragment the floodplain, and have adverse effects on wetland and aquatic habitats by imposing unnatural barriers to plant and wildlife movements. These in turn may accelerate drying of wetland habitats and conifer encroachment of wet meadow and riparian communities. Roads, parking lots, and other impervious surfaces in or near the corridor would continue to release nonpoint-source pollutants into stormwater runoff that would subsequently discharge to low-lying wetlands and 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.

General visitor-related effects include trampling, litter, erosion, compaction, and the unintentional introduction and spread of non-native plants and wildlife. It is anticipated that visitor demand and use of the park (overall) would increase and would continue to affect floodplain wetlands and the aquatic habitat of the Merced River by compacting soils, reducing vegetative cover, altering streambanks, and inducing erosion. Modifications to the river channel and floodplain (through soil compaction, loss of riparian vegetation, and accelerated erosion) influence important stream characteristics such as riffle/pool complexes, substrate type, water quality, channel migration, and riparian and wet meadow cover. Along some stretches of the Merced River in eastern Yosemite Valley, river banks are largely denuded, affecting shading and nutrient dynamics in aquatic habitats. These effects may combine to accelerate bank erosion and widening of the Merced River (i.e., the channel could widen, flatten, and become shallower in reaction to the streambank destabilization caused by visitor use and trampling), increase water temperature, increase suspended sediment, and reduce dissolved oxygen levels. Such changes to the physical characteristics of the river would be harmful to aquatic organisms, and riparian and wetland vegetation. Although these activities are focused in developed and high-use areas, particularly in east Yosemite Valley, the effect on wetlands and the aquatic habitat of the Merced River is felt throughout Yosemite Valley. The impact of existing facilities and visitor use within Yosemite Valley under Alternative 1 could escalate as time passes and the continued effects become worse. Overall, continued habitat degradation would result in a long-term, adverse impact to wetland and aquatic habitats (a biological resource Outstandingly Remarkable Value) within Yosemite Valley.

Impacts in the Merced River Gorge and El Portal. Direct visitor intrusion into the majority of riparian areas of the Merced River gorge is minimal due to topography. The riparian zone would continue to be affected by facilities, roads, pullouts, contaminated stormwater runoff, non-native species, use of non-motorized watercraft (and associated visitor trampling at launch and removal locations), and riprap. Cascades Diversion Dam would remain and continue to affect the aquatic environment of the Merced River. 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 the aquatic habitat of the Merced River. Impervious surfaces accumulate automobile-related pollutants, refuse, and other nonspecific pollutants that are easily transported to adjacent or nearby wetland resources through stormwater runoff. The riparian community through the Merced River gorge, identified as an Outstandingly Remarkable Value, would continue to be affected by use of the El Portal Road (and associated pollutants) and non-native species. These continued effects would be considered adverse and long term.

Impacts in Wilderness Segments of the South Fork. Adverse effects to wetland and aquatic resources of the wilderness segments of the South Fork are generally associated with facilities (existing and proposed) and visitor and stock use. No facilities (other than a few trails) currently occur in the upper (above Wawona) and lower (below Wawona) portions of the South Fork, access is difficult, and visitor and stock use is low. The only perceptible change anticipated under Alternative 1 would be an increase in overall visitors to the park, which may increase pressure on relatively unused portions of the South Fork. Although increased visitor use of the upper and lower reaches of the South Fork would negatively affect wetland and aquatic habitats by increasing erosion, soil compaction, trampling, and refuse; decreasing water quality and vegetative cover; and through the potential introduction of non-native species, topography would continue to limit the majority of visitors that can access these portions of the South Fork. No specific wetland features of the upper or lower South Fork are identified as an Outstandingly Remarkable Value. Therefore, none would be affected by this alternative.

Impacts in Wawona. Under Alternative 1, wetland and aquatic habitats within Wawona would continue to be affected by existing facilities and visitor use. Size, structure, productivity, and continuity (within wetland and between wetland and riverine habitat) would continue to decrease 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.

Visitor use would continue to affect the wetlands and the aquatic habitat of the South Fork by compacting soils, reducing vegetative cover, altering streambanks, and inducing erosion as described above. 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. The anticipated overall increase in visitors to the park may increase pressure on relatively unused portions of the South Fork in the vicinity of Wawona, including Wawona Meadow, a biological resource Outstandingly Remarkable Value.

The ongoing effect of habitat degradation and the foreseeable increase in visitors would result in site-specific, long-term, adverse effects to wetland and riparian habitats of the central South Fork and Wawona.

Summary of Alternative 1 Impacts. Development and visitor activity in the Merced River corridor have affected wetland and aquatic resources. Existing facilities and visitor use under Alternative 1 would result in the continued degradation and further impact on the size, structure, productivity, and continuity of wetland and aquatic habitats. Existing facilities would continue to alter natural habitat and ecosystem patterns. Visitor use and the projected increase in park visitors would continue to cause adverse effects, such as trampling, erosion, and compaction. The combined effects of visitor use and existing facilities would lead to additional alterations in vegetation patterns (e.g., conversion of wet meadow to conifer forest) and modifications to the river channel and floodplain (e.g., channel widening). The National Park Service would continue to implement existing goals and policies (e.g., the 1916 Organic Act, Yosemite Natural Resources Yosemite Management Plan, Yosemite Vegetation Management Plan) and make incremental improvements to wetland and aquatic resources on an ad-hoc basis, as opportunities and resource problems present themselves. For example, hampered by existing development and infrastructure, enhancement and re-establishment of wetlands would continue on a site-by-site basis rather than a parkwide or Valleywide basis. Overall, effects would escalate as time passes and the continued effects worsen. These effects would be concentrated in areas of high visitor use, such as Yosemite Valley and in the vicinity of major trails. In areas of little use (for example a majority of the wilderness reaches of the Merced River, and the upper and lower portions of the South Fork), continued use of existing facilities (e.g., trails) at a similar level of intensity would have no noticeable effects on wetland and aquatic communities.

Cumulative effects to wetland and aquatic resources discussed herein 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 effect local wetland patterns (i.e., within the river corridor) as well as large-scale or regional wetland patterns.

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, University of California, Davis 1996). Development and activity in Yosemite National Park has reduced historic wet meadow acreage by 60-65%. Past and ongoing activities include construction of dams, diversion walls, bridges, roads, pipelines, riprap, recreational use, agriculture, 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 (University of California, 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 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 non-motorized 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).

Present Actions. The El Portal Road Reconstruction Project (NPS) is currently underway from the park boundary to the Cascades Diversion Dam, and affects wetlands of the Merced River immediately adjacent to the roadway. Natural resources are protected during construction by implementation of a compliance monitoring program, erosion and sediment controls, hazardous materials controls, revegetation and reclamation, and excluding construction from sensitive habitats. Such measures ensure the overall protection and enhancement of the hydrologic, biological, geologic, cultural, scenic, scientific, and recreation Outstandingly Remarkable Values in the zone as a whole and other parts of the river corridor. Implementation of these measures reduces the overall effects.

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:

• Several Yosemite campground rehabilitation projects, such as at Bridalveil Horse Camp, Yosemite Creek Campground, Tamarack Campground, Hodgdon Meadow Campground; and Wawona Campground Improvement (NPS)

• The Merced River at Eagle Creek Ecological Restoration Project (NPS)

• Update to the Yosemite Fire Management Plan (NPS), which has a goal of improving ecosystem health and meadow restoration

• Update to the Yosemite Wilderness Management Plan (NPS), which will address land management issues within the wilderness

• Fire Management Action Plan for Wilderness (USFS, Stanislaus)

• The Sierra Nevada Framework for Conservation and Collaboration, and the Management Direction for the John Muir, Ansel Adams and Dinkey Lakes, and Monarch Wildernesses (USFS); Wilderness Boundary Protection Land Exchange, Seventh Day Adventist Camp, Wawona (NPS); each of which will address ecosystem management issues of lands adjacent to Yosemite National Park

• Several transportation-related projects (e.g., Yosemite Area Regional Transportation System [YARTS]) which have the general goals of increasing transportation options and reducing reliance on automobiles in the area

• The Tuolumne Meadows Water and Wastewater Improvements; the White Wolf Water System Improvements, and Hodgdon Meadow Water and Wastewater Treatment Improvements, and Replacement/Rehabilitation of Yosemite Valley Sewer Line (NPS); O'Shaughnessy Compound Water System Improvements (City and Co. San Francisco)

• South Fork Merced River Bridges Replacement (NPS)

Although each of these projects may have site-specific 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 native wetlands. For example, implementation of the Tuolumne Meadows Water and Wastewater Improvements project has the potential to adversely affect wetland resources during construction (short-term), with the long-term, beneficial effect of improving water quality through improved wastewater treatment. Another example is the update to the Yosemite Wilderness Management Plan, which could result in the removal of the Merced Lake High Sierra Camp, reducing site-specific erosion and trampling and possibly stock use.

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

• The Tuolumne Meadows Development Concept Plan, and Tuolumne Wild and Scenic River Management Plan (NPS)

• The Orange Crush Fuels Treatment Projects (USFS, Stanislaus)

• The A-Rock Reforestation (USFS, Stanislaus) and the Rogge-Ackerson Fire Reforestation (Tuolumne Co.)

• The Yosemite Valley Plan (NPS)

• South Entrance/Mariposa Grove Site Planning (NPS), which will restore giant sequoia habitat in the Lower Mariposa Grove of Giant Sequoias in Yosemite National Park

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 anticipate. For example, implementation of the Yosemite Valley Plan is expected to have a long-term, beneficial impact to wetland resources by increasing coordinated management of natural resources and reducing facilities within sensitive habitats. However, short-term, adverse effects of this plan may include temporary construction impacts (e.g., potential reconstruction of Segment D of the El Portal Road Reconstruction Project just above Cascades Diversion Dam). Reconstruction of Segment D could cause short-term adverse impacts to natural resources similar to those currently occurring during reconstruction on Segments A, B, and C. These would include loss of mature riparian vegetation, loss of understory vegetation, impacts to special-status species, loss of topsoil, and footprint effects. 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 Outstandingly Remarkable Values of the Merced River) and implementation of best management practices, compliance monitoring, and restoration.

Reasonably foreseeable projects that could have an adverse effect on regional wetlands include:

• The Yosemite View parcel land exchange, El Portal (NPS)

• Merced River Canyon Trail Acquisition (BLM)

• Several development-related projects, such as the Rio Mesa Area Plan (Madera Co.); Yosemite Motels, El Portal (Mariposa Co.); Silvertip Resort Village Project (Mariposa Co.); University of California, Merced Campus (Merced Co.); Buildout of City of Merced, General Plan; Double Eagle Resort, June Lake (Mono Co.); Tioga Inn, Lee Vining (Mono Co.); June Lake Highlands (Mono Co.); Crane Flat Campus Redevelopment (NPS, YNI); Evergreen Lodge Expansion (Tuolumne Co.); Hardin Flat Lodging and Conference Facility (Tuolumne Co.); Motel and Restaurant, Second Garrotte Basin (Tuolumne Co.); Resources Management Building (NPS); Yosemite West Rezoning Application (NPS); and the Hazel Green Ranch (Mariposa Co.)

• Transportation projects, such as the Highway 41 Extension (Madera Co.); Yosemite Valley Shuttle Bus Stop Improvements (NPS); Road Realignment and Bridge Replacement at Highway 49 and Old Highway (Mariposa Co.); Expansion of Mariposa County Transit System; Mariposa Creek Pedestrian/Bike Path (Mariposa Co.); Evergreen Road Improvements (multi-agency, see Appendix G); and San Joaquin Corridor Rail Projects (DOT, Amtrak)

• Several water-related projects, such as the Replacement/Rehabilitation of Yosemite Valley Sewer Line (NPS); Cherry Dam Fuse Gate, and O'Shaughnessy Dam Well (City and Co. San Francisco)

Cumulative adverse effects would be related to increased facilities, access, and regional growth. Each of the aforementioned projects has the potential to have site-specific, adverse effects on wetland and aquatic resources during construction (short-term) and by direct displacement of resources (long-term). Examples of construction- and human-use-related effects on vegetation patterns include direct displacement of vegetation (e.g., replaced with structures), introduction of non-native species that invade into adjacent natural areas and displace native species (e.g., spread by construction equipment or backyard gardening), fragmentation of habitats that prevents genetic mixing, alteration of natural patterns (e.g., fire suppression around structures, use of herbicides, the introduction of night light), and increased erosion and sedimentation (e.g., during grading activities, overuse of trails). Although each new development is required to mitigate or compensate for adverse effects to wetland and aquatic resources, the mitigation/compensation is generally uncoordinated and does not typically replace natural ecosystem functions or values that were present throughout the region prior to Euro-American settlement.

Wetland and riparian systems of the Merced River and the Sierra Nevada have been substantially altered by development and visitor activities. These changes have negatively influenced wetland size, form, and function and the plants, wildlife, and aquatic species that inhabit them. Cumulative effects would be mixed, combining both adverse and beneficial effects. Cumulative beneficial effects on wetlands include wetland restoration, rehabilitation projects, and ecosystem management. Cumulative adverse effects would be related to past, present, and reasonably foreseeable increased facilities, regional growth, and visitor demand. Several of these cumulative actions could have a long-term, beneficial effect on wetlands and wetland-related Outstandingly Remarkable Values within the river corridor. However, throughout the Sierra Nevada and larger region, regional development and growth could have a net long-term, adverse effect on regional wetland and aquatic resources that would not be compensated by local or regional planning and restoration projects. Therefore, cumulative adverse effects on regional wetland and aquatic habitats due to past, present, and reasonably foreseeable actions, could be major, adverse, and long term.

Although cumulative actions could have a long-term, major, beneficial cumulative effect on wetlands and wetland-related Outstandingly Remarkable Values within the river corridor, throughout the Sierra Nevada and larger region, these past, present, and reasonably foreseeable future actions are likely to increase regional growth (construction and human-use-related effects) and have a long-term, major, adverse cumulative effect on regional wetland patterns (e.g., introduction and spread of non-native species, direct displacement of vegetation by structures) that would not be compensated by piecemeal (i.e., project by project) mitigation. These cumulative actions in combination with Alternative 1 could have a net long-term, adverse effect on regional wetland patterns.

Development and visitor activity in the Merced River corridor have affected wetland and aquatic resources. Existing facilities and visitor use under Alternative 1 would result in the continued degradation and further impact on the size, structure, productivity, and continuity of wetland and aquatic habitats. Existing facilities would continue to alter natural habitat and ecosystem patterns. Visitor use and the projected increase in park visitors would continue to cause adverse effects, such as trampling, erosion, and compaction. The combined effects of visitor use and existing facilities would lead to additional alterations in vegetation patterns (e.g., conversion of wet meadow to conifer forest) and modifications to the river channel and floodplain (e.g., channel widening). The National Park Service would continue to implement existing goals and policies (e.g., the 1916 Organic Act, Yosemite Natural Resources Management Plan, Yosemite Vegetation Management Plan) and make incremental improvements to wetland and aquatic resources on an ad-hoc basis, as opportunities and resource problems present themselves. For example, hampered by existing development and infrastructure, enhancement and re-establishment of woodlands would continue on a site-by-site basis rather than a parkwide or Valleywide basis. Although substantial piecemeal improvements can take place under current direction, "reactive" resource management is not always effective at protecting sensitive resources over the long term. Overall, effects would escalate as time passes and the continued effects worsen. These effects would be concentrated in areas of high visitor use, such as Yosemite Valley and in the vicinity of major trails. In areas of little use (for example a majority of the wilderness reaches of the Merced River, and the upper and lower portions of the South Fork), continued use of existing facilities (e.g., trails) at a similar level of intensity would have no noticeable effects on wetland and aquatic communities.

Although cumulative actions could have a long-term, beneficial cumulative effect on wetlands and wetland-related Outstandingly Remarkable Values within the river corridor, throughout the Sierra Nevada and larger region, these past, present, and reasonably foreseeable future actions are likely to increase regional growth (construction and human-use-related effects) and have a long-term, adverse cumulative effect on regional wetland patterns (e.g., introduction and spread of non-native species, direct displacement of vegetation by structures) that would not be compensated by piecemeal (i.e., project by project) mitigation. These cumulative actions in combination with Alternative 1 could have a net long-term, adverse effect on regional wetland patterns.

Vegetation

Analysis

General Impacts. 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 from application of Alternative 1.

Impacts in the Wilderness Segment of the Upper Main Stem Merced River. Vegetation of the upper 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). Under Alternative 1, use of these facilities would continue consistent with existing conditions. Vegetation at these locations would continue to be negatively affected by development and human and stock use. Existing development would adversely affect vegetation primarily through habitat fragmentation and imposing unnatural barriers to plant and wildlife movements (barriers in turn affect seed source, nutrients, and plant distribution patterns). 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. Types of adverse effects associated with continued human and stock use would include site-specific degradation of water quality (e.g., refuse, fecal coliform bacteria, and other human- and stock-associated pollutants), potential introduction or spread of noxious weeds, and grazing, trampling, compaction and erosion, resulting in loss of natural structure, diversity, and productivity. Vegetation resources are also positively affected by localizing facility- and use-related impacts away from more sensitive areas. These continued actions would have long-term, site-specific, adverse effects on vegetation in the vicinity of facilities and areas of concentrated use.

The degree to which vegetation communities would be affected depends on their position relative to facilities and use as well as sensitivity to perturbation. Riparian, chaparral, and forest communities in close proximity to Merced Lake High Sierra Camp and Backpackers Campground, Little Yosemite Valley Backpackers Campground, Moraine Dome Backpackers Campground and major trail routes would experience site-specific, adverse effects. In all other areas of the upper main stem of the Merced River, continued use of existing facilities (e.g., trails) at a similar level of intensity would have no-net adverse effects on vegetation. Examples of vegetation related Outstandingly Remarkable Values of the upper Merced River include exceptional stands of western juniper and white fir. Although stands of each are adjacent to trails, use of these trails on an annual basis is considered low when compared to high-use trails, such as the trail to Half Dome within Little Yosemite Valley. As such potential effects to these Outstandingly Remarkable Values is considered low under Alternative 1.

Impacts in Yosemite Valley. Under Alternative 1, size, structure, productivity, and continuity (within habitat and between habitats) of vegetation within Yosemite Valley would continue to be affected by existing facilities and visitor use.

Existing facilities, such as roads, bridges, ditches, structures, and campgrounds, would continue to affect vegetation (e.g., roads would continue to drain wet meadows, landscape irrigation would continue to affect native oaks, fire suppression in the vicinity of structures would continue to affect vegetative patterns), fragment connection to the floodplain and have adverse effects on vegetation by imposing unnatural barriers to plant and wildlife movements. Fire management near developed areas would not change under Alternative 1, resulting in continued conifer encroachment into adjacent communities (e.g., oak woodlands, wet meadows, and riparian woodlands). Lack of fire has generally resulted in dense overgrown understory and a shift in species composition to more shade-tolerant coniferous species such as white fir, Douglas-fir, and incense-cedar. Although upland communities would continue to expand and become more continuous through Yosemite Valley, forest health is expected to decline. Summer watering of California black oaks in landscaped areas would continue to contribute to the overall decline of this community in Yosemite Valley by promoting the spread of Armillaria mellea, a fungus that causes root and crown rot of disturbed or severely stressed oaks. The unnaturally dense stands of incense-cedar and ponderosa pine would continue to contribute to the spread of annosus root rot through much of the developed eastern portion of Yosemite Valley (e.g., Upper River and Lower River Campgrounds, Yellow Pine Picnic Area, portions of Yosemite Lodge, and most of the Taft Toe area).

General human-related effects include trampling, unintentional introduction and spread of non-native species (both plant and wildlife), litter, erosion, and compaction. It is anticipated that overall visitor demand and use of the park would increase. Visitor use would continue to affect vegetation by compacting soils, reducing vegetative cover, altering streambanks, and inducing erosion. Modifications to the river channel and floodplain (through soil compaction, loss of riparian vegetation, and accelerated erosion) influence important stream characteristics that may combine to accelerate widening of the Merced River and alter overall vegetative patterns in Yosemite Valley. Trampling and visitor use would continue to adversely affect understory vegetation, introduce and spread non-native species, and impede natural regeneration of native oaks, woody shrubs, and riparian and meadow vegetation.

In general, the ongoing effect of habitat degradation combined with continued visitor use and the foreseeable increase in visitors would aggravate these effects and result in long-term, adverse effects to vegetation within Yosemite Valley. Examples of vegetation-related Outstandingly Remarkable Values within Yosemite Valley include extraordinary examples of the California black oak community, riparian communities, and overall species diversity. These Outstandingly Remarkable Values also would be adversely affected (long-term) by habitat fragmentation, increased conifer dominance, disease, and effects related to facilities and visitor use described above.

Impacts in the Merced River Gorge and El Portal. Direct human intrusion into the majority of riparian areas of the Merced River gorge is minimal due to topography. The riparian zone would continue to be affected by facilities, roads, pullouts, contaminated stormwater runoff, non-native species, use of non-motorized watercraft (and associated human trampling at launch and removal locations), and riprap. The riparian community through the Merced River gorge is listed as an example of an Outstandingly Remarkable Value and would continue to be affected by use of the El Portal Road (and associated pollutants), non-native species, and use of non-motorized watercraft. These potential effects would be considered long term and adverse.

The natural structure, diversity, and productivity of oak communities would continue to be affected by non-native species, fire suppression, and existing facilities. Continued concentrated visitor use and management policies would have site-specific, adverse effects on oak communities. In all other areas of the Merced River gorge, human-related effects to oak vegetation would continue.

Impacts in Wilderness Segments of the South Fork. Adverse effects to vegetation of the upper and lower South Fork are generally associated with facilities (existing and proposed) and visitor and stock use. No facilities, other than a few trails, currently occur in the upper and lower portions of the South Fork, access is difficult, and visitor and stock use is low. The only perceptible change anticipated under Alternative 1 could be an increase in the annual number of visitors to the park that may increase pressure on relatively unused portions of the South Fork. Although increased visitor use of the upper and lower reaches of the South Fork negatively affect vegetation by increasing erosion, soil compaction, trampling, and refuse, decreasing water quality and vegetative cover, and through the potential introduction of non-native species, these effects are considered speculative because topography and limited trail access would continue to limit the majority of visitors that can access these portions of the South Fork.

Impacts in Wawona. Under Alternative 1, vegetation within the central South Fork and Wawona would continue to be affected by existing facilities and visitor use. Size, structure, productivity, and continuity (within and between habitats) would continue to decrease due to conifer encroachment, human trampling, spread of non-native species, continued use of existing development, alteration of natural fire patterns (e.g., in the vicinity of structures), and loss of natural drainage patterns due to roads and diversions. Visitor use would continue to affect the vegetation of the central South Fork by compacting soils, reducing vegetative cover, altering streambanks, and inducing erosion, as described above. These effects would be long term and adverse.

The anticipated increase in overall visitors to the park also may increase pressure on relatively unused portions of the South Fork in the vicinity of Wawona, including Wawona Meadow, which is listed as an example of a biological resource Outstandingly Remarkable Value. Although Wawona Meadow is large and generally intact, it has been the site of repeated human intrusion since the turn of the century. The meadow continues to be affected by ditches, a golf course, a sprayfield for reclaimed water, and helicopter staging. These uses would remain and would continue to adversely affect Wawona Meadow.

Summary of Alternative 1 Impacts. Existing development and human activity in the Merced River corridor affect vegetation patterns. Implementation of Alternative 1 could result in the continued degradation of size, structure, productivity, and continuity of habitats by existing facilities and visitor use. Existing facilities could continue to alter natural habitat and ecosystem patterns. Visitor use and the projected increase in park visitors would continue to cause adverse effects such as trampling, erosion, and compaction. The combined affects of visitor use and existing facilities can lead to alterations in vegetation patterns (e.g., type conversion of wet meadow to conifer forest) and modifications to the river channel and floodplain (e.g., channel widening). The National Park Service could continue to implement existing goals and policies (e.g., the 1916 Organic Act, Yosemite Natural Resources Management Plan, Yosemite Vegetation Management Plan) and make incremental improvements to vegetation on an ad-hoc basis, as opportunities and resource problems are presented. For example, hampered by existing development and infrastructure, enhancement and re-establishment of woodlands could continue on a site-by-site basis rather than a parkwide or Valleywide basis. Although substantial piecemeal improvements can take place under current direction, "reactive" resource management is not always effective at protecting sensitive resources over the long-term. Overall, effects could escalate as time passes and the effects on natural vegetative patterns worsened. These effects would be concentrated in areas of high visitor use such as Yosemite Valley, El Portal, Wawona, and in the vicinity of major trails. In areas of little use (e.g., a majority of the upper main stem of the Merced River, and the upper and lower portions of the South Fork), continued use of existing facilities (e.g., trails) at a similar level of intensity would have no perceptible effects on native vegetation.

Cumulative Impacts

Cumulative effects to vegetation discussed herein 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 effect 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 long-term, adverse alterations to native vegetation patterns 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 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 non-motorized 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).

Present Actions. The El Portal Road Reconstruction Project (NPS) is currently underway from the park boundary to the Cascades Diversion Dam, and affects vegetation of the Merced River immediately adjacent to the roadway. Natural resources are protected during construction by implementation of a compliance monitoring program, erosion and sediment controls, hazardous materials controls, revegetation and reclamation, and excluding construction from sensitive habitats. Such measures ensure the overall protection and enhancement of the hydrologic, biological, geologic, cultural, scenic, scientific, and recreation Outstandingly Remarkable Values in the zone as a whole and other parts of the river corridor. Implementation of these measures reduces the overall effects.

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 vegetation include:

• Several Yosemite campground rehabilitation projects, such as at Bridalveil Horse Camp, Yosemite Creek Campground, Tamarack Campground, and Hodgdon Meadow Campground; and Wawona Campground Improvement (NPS)

• The Merced River at Eagle Creek Ecological Restoration Project (NPS)

• Update to the Yosemite Fire Management Plan (NPS), which has a goal of improving ecosystem health and meadow restoration

• Update to the Yosemite Wilderness Management Plan (NPS), which will address land management issues within the wilderness

• Fire Management Action Plan for Wilderness (USFS, Stanislaus)

• The Sierra Nevada Framework for Conservation and Collaboration, and the Management Direction for the John Muir, Ansel Adams and Dinkey Lakes, and Monarch Wildernesses (USFS); Wilderness Boundary Protection Land Exchange, Seventh Day Adventist Camp, Wawona (NPS); each of which will address ecosystem management issues of lands adjacent to Yosemite National Park

• Several transportation-related projects (e.g., Yosemite Area Regional Transportation System [YARTS]) which have the general goals of increasing transportation options and reducing reliance on automobiles in the area

Although each of these projects may have slight site-specific 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 native vegetation. For example, the update to the Yosemite Wilderness Management Plan could result in the removal of the Merced Lake High Sierra Camp, reducing site-specific erosion and trampling and possibly stock use.

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

• The Tuolumne Meadows Development Concept Plan, and Tuolumne Wild and Scenic River Management Plan (NPS)

• The Tuolumne Meadows Water and Wastewater Improvements; the White Wolf Water System Improvements, Hodgdon Meadow Water and Wastewater Treatment Improvements, and Replacement/Rehabilitation of Yosemite Valley Sewer Line (NPS); O'Shaughnessy Compound Water System Improvements (City and Co. San Francisco)

• The Orange Crush Fuels Treatment Projects (USFS, Stanislaus)

• The A-Rock Reforestation (USFS, Stanislaus) and the Rogge-Ackerson Fire Reforestation (Tuolumne Co.)

• The Yosemite Valley Plan (NPS), which would implement the goals and actions of the 1980 General Management Plan (NPS)

• South Fork Merced River Bridges Replacement (NPS)

• South Entrance/Mariposa Grove Site Planning (NPS), which will restore giant sequoia habitat in the Lower Mariposa Grove of Giant Sequoias in Yosemite National Park

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 anticipate. For example, implementation of the Tuolumne Meadows Water and Wastewater Improvements project has the potential to adversely affect vegetation resources during construction (short-term), with the long-term, beneficial effect of improving water quality through improved wastewater treatment. Another example would be implementation of the Yosemite Valley Plan. Overall, implementation of this plan is expected to have a long-term, beneficial impact to vegetation resources by increasing coordinated management of natural resources and reducing facilities within sensitive habitats. However, short-term, adverse effects of this plan may include temporary construction impacts (e.g., potential reconstruction of Segment D of the El Portal Road Reconstruction Project just above Cascades Diversion Dam). Reconstruction of Segment D could cause short-term adverse impacts to natural resources similar to those currently occurring during reconstruction on Segments A, B, and C. These would include loss of mature (overstory) vegetation, loss of understory vegetation, impacts to special-status species, loss of topsoil, and footprint effects. 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 Outstandingly Remarkable Values of the Merced River) and implementation of best management practices, compliance monitoring, and restoration.

Reasonably foreseeable projects that could have an adverse effect on regional vegetation include:

• The Yosemite View parcel land exchange, El Portal (NPS)

• Merced River Canyon Trail Acquisition (BLM)

• Several development-related projects, such as the Rio Mesa Area Plan (Madera Co.); Yosemite Motels, El Portal (Mariposa Co.); Silvertip Resort Village Project (Mariposa Co.); University of California, Merced Campus (Merced Co.); Buildout of City of Merced, General Plan; Double Eagle Resort, June Lake (Mono Co.); Tioga Inn, Lee Vining (Mono Co.); June Lake Highlands (Mono Co.); Crane Flat Campus Redevelopment (NPS, YNI); Evergreen Lodge Expansion (Tuolumne Co.); Hardin Flat Lodging and Conference Facility (Tuolumne Co.); Motel and Restaurant, Second Garrotte Basin (Tuolumne Co.); Resources Management Building (NPS); Yosemite West Rezoning Application (NPS); and the Hazel Green Ranch (Mariposa Co.)

• Transportation projects, such as the Highway 41 Extension (Madera Co.); Yosemite Valley Shuttle Bus Stop Improvements (NPS); Road Realignment and Bridge Replacement of Highway 49 and Old Highway (Mariposa Co.); Expansion of Mariposa County Transit System; Mariposa Creek Pedestrian/Bike Path (Mariposa Co.); Evergreen Road Improvements (multi-agency, see Appendix G); and San Joaquin Corridor Rail Projects (DOT, Amtrak)

• Several water-related projects, such as the Replacement/Rehabilitation of Yosemite Valley Sewer Line (NPS); Cherry Dam Fuse Gate, and O'Shaughnessy Dam Well (City and Co. San Francisco)

Cumulative adverse effects would be related to increased facilities, access, and regional population growth. Each of the aforementioned projects has the potential to have substantial site-specific adverse effects on vegetation resources during construction (short-term) and by direct displacement of resources (long-term). The larger effect of these actions is related to population and regional growth and their subsequent effect on natural resources, including native vegetation patterns. Regional population growth primarily affects regional vegetation patterns through construction (e.g., new housing and infrastructure) and visitor use. Examples of construction- and human-use-related effects on vegetation patterns include direct displacement of vegetation (e.g., replaced with structures), introduction of non-native species that invade into adjacent natural areas and displace native species (e.g., spread by construction equipment or backyard gardening), fragmentation of habitats that prevents genetic mixing, alteration of natural patterns (e.g., fire suppression around structures, use of herbicides, the introduction of night light), and increased erosion and sedimentation (e.g., during grading activities, overuse of trails). Although each new development is required to mitigate or compensate for adverse effects to vegetation, the mitigation/compensation is generally uncoordinated and does not typically replace natural ecosystem functions or values that were present throughout the region prior to Euro-American settlement. In total, regional development and growth could have a net long-term, major, adverse effect on regional vegetation resources that would not be compensated by regional planning and restoration projects discussed above.

Although cumulative actions could have a long-term, beneficial cumulative effect on vegetation and vegetation-related Outstandingly Remarkable Values within the river corridor, throughout the Sierra Nevada and larger region, these past, present, and reasonably foreseeable future actions are likely to increase regional growth (construction and human-use-related effects) and have a long-term, adverse cumulative effect on regional vegetation patterns (e.g., introduction and spread of non-native species, direct displacement of vegetation by structures) that would not be compensated by piecemeal (i.e., project by project) mitigation. These cumulative actions in combination with Alternative 1 could have a net long-term adverse effect on regional vegetation patterns.

Existing development and human activity in the Merced River corridor affect vegetation patterns. Implementation of Alternative 1 could result in the continued degradation of size, structure, productivity, and continuity of habitats by existing facilities and visitor use. Existing facilities could continue to alter natural habitat and ecosystem patterns. Visitor use and the projected increase in park visitors would continue to cause adverse effects such as trampling, erosion, and compaction. The combined affects of visitor use and existing facilities can lead to alterations in vegetation patterns (e.g., type conversion of wet meadow to conifer forest) and modifications to the river channel and floodplain (e.g., channel widening). The National Park Service could continue to implement existing goals and policies (e.g., the 1916 Organic Act, Yosemite Natural Resources Management Plan, Yosemite Vegetation Management Plan) and make incremental improvements to vegetation on an ad-hoc basis, as opportunities and resource problems are presented. For example, hampered by existing development and infrastructure, enhancement and re-establishment of woodlands could continue on a site-by-site basis rather than a parkwide or Valleywide basis. Although substantial piecemeal improvements can take place under current direction, "reactive" resource management is not always effective at protecting sensitive resources over the long-term. Overall, effects could escalate as time passes and the effects on natural vegetative patterns worsened. These effects would be concentrated in areas of high visitor use such as Yosemite Valley, El Portal, Wawona, and in the vicinity of major trails. In areas of little use (e.g., a majority of the upper main stem of the Merced River, and the upper and lower portions of the South Fork), continued use of existing facilities (e.g., trails) at a similar level of intensity would have no perceptible effects on native vegetation.

Although cumulative actions could have a long-term, beneficial cumulative effect on vegetation and vegetation-related Outstandingly Remarkable Values within the river corridor, throughout the Sierra Nevada and larger region, these past, present, and reasonably foreseeable future actions are likely to increase regional growth (construction and human-use-related effects) and have a long-term, adverse cumulative effect on regional vegetation patterns (e.g., introduction and spread of non-native species, direct displacement of vegetation by structures) that would not be compensated by piecemeal (i.e., project by project) mitigation. These cumulative actions in combination with Alternative 1 could have a net long-term adverse effect on regional vegetation patterns.

Wildlife

Analysis

General Impacts. 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., picnic area and parking lot development, 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).

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 (e.g., the VERP framework, management zoning, the River Protection Overlay, criteria and considerations).

Impacts in the Wilderness Segment of the Upper Main Stem Merced River. 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. Wildlife habitat within the upper Merced River are generally intact. If campground and trail use continues at current levels, adverse impacts could occur at scarcer wet-meadow habitats and result in declines in associated species. For example, trampling of meadow habitat could reduce habitat for voles, reducing forage availability for great gray owls and California kingsnake.

Although administrative and concessioner stock (horses and mules) is typically contained in corrals and pastures away from the river, there would be an adverse impact on wildlife use of the corral areas (for example, cowbirds tend to occur in areas of heavy horse use). Likewise, the continued use of trails by horses and mules could increase cowbird parasitism, in addition to the effect of runoff from trails. Runoff can affect adjacent aquatic habitats by introducing unnaturally high levels of nutrients. Horse and mule droppings could, furthermore, lead to the introduction of non-native plant species and cause locally increased populations of insects such as flies.

Continued concentrated human use could have a site-specific, adverse effect on wildlife in the vicinity of the Merced Lake High Sierra Camp and Little Yosemite Valley Backpackers Campground through trampling of understory vegetation. Concentrated human use would have a mixture of adverse and beneficial effects. Concentrated use could perpetuate a long-term, adverse impact by locally reducing understory vegetation and downed wood (from firewood collection), causing direct disturbance of wildlife, and providing unnatural food sources. On the other hand, it could have a beneficial effect on the park's management of human/mountain lion encounters, which are more common when visitors disperse into little-used areas (Beier 1991). In all other areas of the upper Merced River, human-related effects to wildlife would continue except in site-specific locations where small concentrations of human use cause local, adverse impacts. The presence of food storage devices at Little Yosemite and Merced Lake Backpackers Campgrounds would have a long term, localized, beneficial effect by providing failproof food storage.

Coniferous forest habitats along the upper Merced River are structurally diverse and are expected to continue to support a full community of associated wildlife species, with the exception of site-specific, adverse impacts in popular, dispersed campsites or visitor use areas. Further downstream (into Little Yosemite Valley), in areas with less understory vegetation, continued concentrated human use along the north side of the Merced River would aggravate this affect over time and could have a site-specific, adverse effect on wildlife by degrading habitat within Little Yosemite Valley.

Impacts in Yosemite Valley. Heavily used areas in the Valley can approach the level of disturbance within an urban park. During reconnaissance surveys in 1998, for example, bird diversity at Yosemite Falls was characterized by a preponderance of disturbance-tolerant species. Earlier researchers at the park (Foin et al. 1977, cited in Knight and Gutzwiller 1995) found that Brewer's blackbirds and mountain chickadee increased in areas near visitor trails, while other species decreased (e.g., dark-eyed junco).

As discussed in the previous section, meadow habitat acreage in the Valley has substantially diminished from levels present during pre-Euro-American times and has impacted dependent wildlife species such as Pacific tree frog or red-winged blackbird. The park has already instituted meadow restoration programs that illustrate how productive these habitats can be.

Overall, continued use of facilities at a similar level of intensity could have an adverse effect on wildlife use of the riparian corridor in Yosemite Valley. Wildlife and habitats are already greatly affected by the overall amount of noise, traffic, and human presence, and the effect would continue for riparian-dependent species (e.g., belted kingfisher) at facilities such as North and Lower Pines Campgrounds and Camp 6.

Aquatic habitats have long been subject to modification through the removal of woody debris from the stream channel, a practice that affected natural stream dynamics, reduced habitat diversity for aquatic organisms, and affected nutrient cycling in these habitats.

In forested habitats, encroachment of conifers into California black oak woodlands has probably altered species composition, abundance, and diversity. This situation could continue under Alternative 1 due to the inability to manage trees within and surrounding developed areas with prescribed fire. The encroachment of conifers into California black oak woodlands has affected the availability of acorns as an important seasonal food source for species such as black bears, mule deer, acorn woodpeckers, gray squirrels, and numerous small rodents. Furthermore, conifers provide less suitable habitat for species such as great-horned owls, yellow-rumped warbler, and western bluebird. The impact would be long term and adverse (an ultimate loss of diversity), and, could affect one of Yosemite Valley's Outstandingly Remarkable Values (large stands of black oak).

Impacts in the Merced River Gorge and El Portal. Montane hardwood conifer becomes the dominant type adjacent to riparian areas below Yosemite Valley. This type is broadly transitional between upper-elevation forest types to chaparral and is thus the most important type for migratory wildlife and their associated predators. Access among habitats by wildlife is affected 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-made barriers. The quality of these north-facing habitats is recognized as an Outstandingly Remarkable Value in the El Portal area.

Impacts in the Wilderness Segments of the South Fork. Habitats upstream and downstream of Wawona along the South Fork are relatively inaccessible and intact. Implementation of Alternative 1 would not substantially alter the form or function of these communities.

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, and the fishery^[2] along South Fork is designated a biological resource Outstandingly Remarkable Value under current direction, as are the meadow and wetland communities in Wawona. A survey in 1998 again found willow flycatcher in this location, but breeding has not yet been confirmed. The species is indicative of an intact meadow-riparian complex.

For the coniferous and deciduous forests adjacent to Wawona, the principal impact is fragmentation due to existing development and use. With the foreseeable increase in visitors, this alternative could result in a long-term, adverse impact to wildlife (Andrén 1994).

The South Fork supports self-sustaining populations of brook, rainbow, and brown trout. Through Wawona, the South Fork also supports introduced Sacramento pikeminnow, Sacramento sucker, and hardhead. There is less pressure by anglers on the South Fork fisheries than on the main stem due to difficulty of access and terrain. There could be adverse impacts under Alternative 1, owing to deferred opportunities for restoration and protection.

Summary of Alternative 1 Impacts. Past wildlife management practices, development, and human activity in the Merced River corridor have adversely affected wildlife habitats and patterns. Under Alternative 1 four basic adverse impacts would continue to occur and are expected to worsen over time. These include degradation in habitat quality for riparian and wet-meadow-dependent wildlife; loss of habitat connectivity and increase in habitat fragmentation; an increase in human-related disturbance, and continued stress on wildlife through factors such as the increasing presence of non-native species and disturbance-tolerant wildlife. The National Park Service would continue to implement existing goals and policies (e.g., the 1916 Organic Act, Yosemite Natural Resources Management Plan, Yosemite Vegetation Management Plan) and make incremental improvements on an ad-hoc basis, as opportunities and resource problems present themselves. For example, hampered by existing development and infrastructure, enhancement and re-establishment of woodlands would continue on a site-by-site basis rather than on a parkwide or Valleywide basis. Although substantial piecemeal improvements can take place under current direction, "reactive" resource management is not always effective at protecting sensitive resources over the long term. Overall, effects could escalate as time passed and the effects on natural wildlife patterns could become worse. These effects would be concentrated in areas of high human use such as Yosemite Valley, El Portal, and Wawona, where the loss of species diversity and habitat has already occurred.

Cumulative effects to wildlife discussed herein 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 effect 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 beginning 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 construction of dams, diversion walls, bridges, roads, pipelines, riprap, recreational use, 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 Fellars 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 Sierra Nevada-wide amphibian declines; 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 non-motorized 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).

Present Actions. The El Portal Road Reconstruction Project (NPS) is currently underway from the park boundary to the Cascades Diversion Dam, and affects wildlife of the Merced River immediately adjacent to the roadway. Natural resources are protected during construction by implementation of a compliance monitoring program, erosion and sediment controls, hazardous materials controls, revegetation and reclamation, and excluding construction from sensitive habitats. Such measures ensure the overall protection and enhancement of the hydrologic, biological, geologic, cultural, scenic, scientific, and recreation Outstandingly Remarkable Values in the zone as a whole and other parts of the river corridor. Implementation of these measures reduces the overall effects.

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 wildlife include:

• Several Yosemite campground rehabilitation projects, such as at Bridalveil Horse Camp, Yosemite Creek Campground, Tamarack Campground, Hodgdon Meadow Campground; and Wawona Campground Improvement (NPS)

• The Merced River at Eagle Creek Ecological Restoration Project (NPS)

• Update to the Yosemite Fire Management Plan (NPS), which has a goal of improving ecosystem health and meadow restoration

• Update to the Yosemite Wilderness Management Plan (NPS), which will address land management issues within the wilderness

• Fire Management Action Plan for Wilderness (USFS, Stanislaus)

• The Sierra Nevada Framework for Conservation and Collaboration, and the Management Direction for the John Muir, Ansel Adams and Dinkey Lakes, and Monarch Wildernesses (USFS); Wilderness Boundary Protection Land Exchange, Seventh Day Adventist Camp, Wawona (NPS); each of which will address ecosystem management issues of lands adjacent to Yosemite National Park

• Several transportation-related projects (e.g., Yosemite Area Regional Transportation System [YARTS]) which have the general goals of increasing transportation options and reducing reliance on automobiles in the area

Although each of these projects may have slight site-specific 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 native wildlife. For example, the update to the Yosemite Wilderness Management Plan could result in the removal of the Merced Lake High Sierra Camp, reducing site-specific erosion and trampling and possibly stock use.

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

• The Tuolumne Meadows Development Concept Plan, and Tuolumne Wild and Scenic River Management Plan (NPS)

• The Tuolumne Meadows Water and Wastewater Improvements; the White Wolf Water System Improvements, Hodgdon Meadow Water and Wastewater Treatment Improvements, Replacement/Rehabilitation of Yosemite Valley Sewer Line (NPS); O'Shaughnessy Compound Water System Improvements (City and Co. San Francisco)

• The Orange Crush Fuels Treatment Projects (USFS, Stanislaus)

• The A-Rock Reforestation (USFS, Stanislaus) and the Rogge-Ackerson Fire Reforestation (Tuolumne Co.)

• The Yosemite Valley Plan (NPS), which would implement the goals and actions of the 1980 General Management Plan (NPS)

• South Fork Merced River Bridges Replacement (NPS)

• South Entrance/Mariposa Grove Site Planning (NPS), which will restore giant sequoia habitat in the Lower Mariposa Grove of Giant Sequoias in Yosemite National Park

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 anticipate. For example, implementation of the Tuolumne Meadows Water and Wastewater Improvements project has the potential to adversely affect wildlife resources during construction (short-term), with the long-term, beneficial effect of improving water quality through improved wastewater treatment. Another example would be implementation of the Yosemite Valley Plan. Overall, implementation of this plan is expected to have a long-term, beneficial impact to wildlife resources by increasing coordinated management of natural resources and reducing facilities within sensitive habitats. However, short-term, adverse effects of this plan may include temporary construction impacts (e.g., potential reconstruction of Segment D of the El Portal Road Reconstruction Project just above Cascades Diversion Dam). Reconstruction of Segment D could cause short-term adverse impacts to natural resources similar to those currently occurring during reconstruction on Segments A, B, and C. These would include loss of mature (overstory) wildlife, loss of understory vegetation, impacts to special-status species, loss of topsoil, and footprint effects. 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 Outstandingly Remarkable Values of the Merced River) and implementation of best management practices, compliance monitoring, and restoration.

Reasonably foreseeable projects that could have an adverse effect on regional wildlife include:

• The Yosemite View parcel land exchange, El Portal (NPS)

• Merced River Canyon Trail Acquisition (BLM)

• Several development-related projects, such as the Rio Mesa Area Plan (Madera Co.); Yosemite Motels, El Portal (Mariposa Co.); Silvertip Resort Village Project (Mariposa Co.); University of California, Merced Campus (Merced Co.); Buildout of City of Merced, General Plan; Double Eagle Resort, June Lake (Mono Co.); Tioga Inn, Lee Vining (Mono Co.); June Lake Highlands (Mono Co.); Crane Flat Campus Redevelopment (NPS, YNI); Evergreen Lodge Expansion (Tuolumne Co.); Hardin Flat Lodging and Conference Facility (Tuolumne Co.); Motel and Restaurant, Second Garrotte Basin (Tuolumne Co.); Resources Management Building (NPS); Yosemite West Rezoning Application (NPS); and the Hazel Green Ranch (Mariposa Co.)

• Transportation projects, such as the Highway 41 Extension (Madera Co.); Yosemite Valley Shuttle Bus Stop Improvements (NPS); Road Realignment and Bridge Replacement at Highway 49 and Old Highway (Mariposa Co.); Expansion of Mariposa County Transit System; Mariposa Creek Pedestrian/Bike Path (Mariposa Co.); Evergreen Road Improvements (multi-agency, see Appendix G); and San Joaquin Corridor Rail Projects (DOT, Amtrak)

• Several water-related projects, such as the Replacement/Rehabilitation of Yosemite Valley Sewer Line (NPS); Cherry Dam Fuse Gate, and O'Shaughnessy Dam Well (City and Co. San Francisco)

Cumulative adverse effects would be related to increased facilities, access, and regional population growth. Each of the aforementioned projects has the potential to have substantial site-specific adverse effects on wildlife resources during construction (short-term) and by direct displacement of resources (long-term). The larger effect of these actions is related to population and regional growth and their subsequent effect on natural resources, including native wildlife patterns. Regional population growth primarily affects regional wildlife patterns through construction (e.g., new housing and infrastructure) and human use. Examples of construction- and human-use-related effects on wildlife patterns include direct displacement of wildlife (e.g., replaced with structures), introduction of non-native species that invade into adjacent natural areas and displace native species (e.g., spread by construction equipment or backyard gardening), fragmentation of habitats that prevents genetic mixing, alteration of natural patterns (e.g., fire suppression around structures, use of herbicides, the introduction of night light), and increased erosion and sedimentation (e.g., during grading activities, overuse of trails). More importantly, some of the projects provide for increased residential growth adjacent to the park and would accommodate increased recreational development. In total, regional development and growth could have a net long-term, moderate, adverse effect on wildlife associated with the Merced River corridor. For the species at higher elevations, the effects are somewhat mitigated by resource protection planning and restoration. Although each new development is required to mitigate or compensate for adverse effects to wildlife, the mitigation/compensation is generally uncoordinated and does not typically replace natural ecosystem functions or values that were present throughout the region prior to Euro-American settlement. In total, regional development and growth could have a net long-term, moderate, adverse effect on regional wildlife resources that would not be compensated by regional planning and restoration projects discussed above.

Wildlife communities have been manipulated almost since the beginning of the park, and these actions have negatively influenced wildlife and wildlife habitat. Past, present, and future reasonably foreseeable cumulative effects would be mixed, combining both adverse and beneficial effects. Cumulative beneficial effects on wildlife include habitat restoration and rehabilitation projects and ecosystem management. Cumulative adverse effects would be related to increased facilities, regional growth, and visitor demand. Although general effects associated with this alternative are beneficial, the overall cumulative effect of other past, present, and reasonably foreseeable actions, in combination with this alternative would be adverse, and long term.

Past wildlife management practices, development, and human activity in the Merced River corridor have adversely affected wildlife habitats and patterns. Under Alternative 1 four basic adverse impacts would continue to occur and are expected to worsen over time. These include degradation in habitat quality for riparian and wet-meadow-dependent wildlife; loss of habitat connectivity and increase in habitat fragmentation; an increase in human-related disturbance, and continued stress on wildlife through factors such as the increasing presence of non-native species and disturbance-tolerant wildlife. The National Park Service would continue to implement existing goals and policies (e.g., the 1916 Organic Act, Natural Resources Management Plan, Vegetation Management Plan) and make incremental improvements on an ad-hoc basis, as opportunities and resource problems present themselves. For example, hampered by existing development and infrastructure, enhancement and re-establishment of woodlands would continue on a site-by-site basis rather than on a parkwide or Valleywide basis. Although substantial piecemeal improvements can take place under current direction, "reactive" resource management is not always effective at protecting sensitive resources over the long term. Overall, effects could escalate as time passed and the effects on natural wildlife patterns could become worse. These effects would be concentrated in areas of high human use such as Yosemite Valley, El Portal, and Wawona, where the loss of species diversity and habitat has already occurred.

Wildlife communities have been manipulated almost since the beginning of the park, and these actions have negatively influenced wildlife and wildlife habitat. Past, present, and future reasonably foreseeable cumulative effects would be mixed, combining both adverse and beneficial effects. Cumulative beneficial effects on wildlife include habitat restoration and rehabilitation projects and ecosystem management. Cumulative adverse effects would be related to increased facilities, regional growth, and visitor demand. Although general effects associated with this alternative are beneficial, the overall cumulative effect of other past, present, and reasonably foreseeable actions, in combination with this alternative would be adverse and long term.

Rare, Threatened, and Endangered Species

Analysis

General Impacts. Due to the programmatic and prescriptive nature of the project, it is difficult to predict impacts on individual species with any accuracy. No attempt is made to quantify discrete impacts to individual species and the conclusions herein are limited to general statements about rare, threatened, or endangered (sometimes referred to as "special-status") plants and animals considered as a whole. A more detailed biological assessment was presented to the U.S. Fish and Wildlife Service in compliance with Section 7 of the Federal Endangered Species Act in January 2000. A revised Biological Assessment, based on this Merced River Plan/FEIS will be submitted to the U.S. Fish and Wildlife Service in June 2000.

All other aspects of the analysis being equal, species present in low numbers or of limited distribution are the most sensitive to impacts. Simultaneously, species of lesser rarity but greater vulnerability to the types of actions that might take place (as a result of management decisions under the plan) are also important as measures of adverse impact 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 the Merced River Plan) and are discussed below as examples of possible effects.

River-related rare, threatened, and endangered species are considered a general biologic resource Outstandingly Remarkable Value. Therefore, any adverse or beneficial effect described herein to river-related rare, threatened, or endangered species is considered to have a corresponding effect on the general Outstandingly Remarkable Value.

The following discussion provides an overview of the types of impacts to rare, threatened, and endangered species that could occur within each segment of the Merced River corridor from application of Alternative 1.

Impacts in the Wilderness Segment of the Upper Main Stem Merced River. Habitats of the wilderness reaches of the Merced River are 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). Under Alternative 1, use of these facilities could continue consistent with existing conditions. Habitats at these locations could continue to be negatively affected by development and visitor and stock use. Existing development could adversely affect rare, threatened, and endangered species and their habitats, primarily through habitat fragmentation and the imposition of unnatural barriers to plant and wildlife movements (barriers in turn affect seed sources, nutrients, and plant distribution patterns). 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. Types of adverse effects associated with continued visitor and stock use include site-specific degradation of water quality (e.g., refuse, fecal coliform bacteria, and other human- and stock-associated pollutants), potential introduction or spread of noxious weeds (primarily by stock), and grazing, trampling, compaction and erosion, resulting in loss of natural structure, diversity, and productivity.

The degree to which rare, threatened, and endangered species would be affected depends on individual species requirements habitat requirements, position relative to facilities and use, and sensitivity to perturbation. Rare, threatened, and endangered species that occur in close proximity to 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.

The following examples describe general actions and related adverse effects that could occur in the vicinity of facilities and areas of concentrated use. These effects are generally considered long-term and adverse. In all other areas of the wilderness reaches of the main stem of the Merced River, continued use of existing facilities (e.g., trails) at a similar level of intensity would have no effects on 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 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 may have long-term, adverse effects on habitat for northern goshawk and Cooper's hawk at this location, as repeated disturbances near nest trees can result in nest failure or abandonment.

Impacts in Yosemite Valley. Under Alternative 1, size, structure, productivity, and continuity (within habitat and between habitats) of habitats within Yosemite Valley could continue to be affected by existing facilities, stock, and visitor use.

Existing facilities, such as roads, bridges, ditches, and campgrounds, could continue to affect habitats (e.g., drain wet meadows), fragment, and have adverse effects on rare, threatened, and endangered species by imposing unnatural barriers to plant and wildlife movements. Fire management near developed areas would not change under Alternative 1 and could promote mistletoe and oak galls and continued conifer encroachment into adjacent communities (e.g., oak woodlands, wet meadows, and riparian woodlands). Lack of fire has generally resulted in dense overgrown understory and a shift in species composition to more shade-tolerant coniferous species such as white fir, Douglas-fir, and incense-cedar. Roads, parking lots, and other impervious surfaces in or near the corridor could continue to release nonpoint-source pollutants into stormwater runoff that could subsequently discharge to low-lying wetlands and the aquatic habitat of the Merced River.

Within Yosemite Valley, the effects of stock are concentrated at stables and along major trails. General human-related effects include trampling, litter, noise, night lighting, erosion, compaction, and unintentional introduction and spread of non-native plants and wildlife. It is anticipated that overall visitor demand and use of the park would increase. Visitor use could continue to affect habitat for rare, threatened, and endangered species by compacting soils, reducing vegetative cover, altering streambanks, and inducing erosion. Modifications to the river channel and floodplain (through soil compaction, loss of riparian vegetation, and accelerated erosion) influence important stream characteristics that may combine to accelerate widening of the Merced River and alter overall vegetative patterns in Yosemite Valley. Trampling and visitor use could continue to adversely affect understory vegetation, introduce and spread non-native species, and impede natural regeneration of native oaks, woody shrubs, and riparian and meadow vegetation.

The following examples describe general actions and related adverse effects that could occur to rare, threatened, and endangered species within Yosemite Valley:

• Trampling of meadows (e.g., at the base of El Capitan) could have direct effects on rare plants, such as habitat for ground-dwelling wildlife species (e.g., voles), therefore reducing the prey base for great gray owl.

• Continued high visitor use and continuation of the stables within Yosemite Valley would promote brown-headed cowbirds to the detriment of species such as yellow warbler.

• Riparian-dependent species (e.g., belted kingfisher) would continue to be adversely affected by 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, yellow-rumped warbler, and western bluebird and plant species including sugar stick, boreal bedstraw, false pimpernel, azure penstemon, and ladies. tresses that depend more heavily on meadow and oak woodland habitats.

• Non-native planted trout could continue to affect native rainbow trout strains. Bullfrogs could continue to affect special-status amphibians, or possible reintroduction efforts (e.g., for California red-legged frog).

• Continued non-native predation, fragmentation of aquatic and floodplain habitats, use of non-motorized watercraft, swimming, and fishing may 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 to hawks (e.g., Cooper's hawk, sharp-shinned hawk) within Yosemite Valley.

• Implementation of this alternative could negatively affect the success of reintroduction or recolonization of species, such as harlequin duck and willow flycatcher, now extirpated from Yosemite Valley.

The National Park Service could continue to implement existing goals and policies (e.g., the 1916 Organic Act, Yosemite Natural Resources Management Plan, Yosemite Vegetation Management Plan) and make incremental improvements on an ad-hoc basis as opportunities and resource problems present themselves. For example, hampered by existing development and infrastructure, enhancement and re-establishment of oak woodlands would continue on a site-by-site rather than a Valleywide basis. Although substantial improvements can take place under current direction and implementation, "reactive" resource management is not always effective at protecting sensitive resources over the long term.

In general, the ongoing effect of habitat degradation combined with continued visitor use and the foreseeable increase in visitors could make the current situation worse and result in long-term adverse effects to rare, threatened, and endangered species within Yosemite Valley. For example, potential effects to Cooper's hawk would likely be adverse, given the abundance of suitable habitat away from the river while continued effects to already rare or absent species such as California red-legged frog and great gray owl, would be considered long-term and adverse.

Impacts in the Merced River Gorge and El Portal. Direct human intrusion into the majority of riparian and other habitat areas of the Merced River gorge is minimal due to topography. The riparian zone could continue to be affected by facilities, roads, turnouts, contaminated stormwater runoff, non-native species, use of non-motorized watercraft (and associated visitor trampling at launch and removal locations), and riprap. Roads, parking lots, and other impervious surfaces in or near the corridor could continue to release nonpoint-source pollutants into stormwater runoff that could subsequently discharge to the aquatic habitat of the Merced River. The natural structure, diversity, and productivity of oak communities could continue to be affected by non-native species, fire suppression, and existing facilities. Continued concentrated visitor use and management policies could have site-specific, adverse effects on oak communities. In all other areas of the Merced River gorge, human-related effects to oak habitats would continue.

The following examples describe general actions and related adverse effects that could occur to rare, threatened, and endangered species within the Merced River gorge.

• Use of the El Portal Road (and associated pollutants), presence of non-native species, and trampling (e.g., at launch and removal sites for non-motorized watercraft) could have adverse effects on special-status species such as Tompkin's sedge or Valley elderberry longhorn beetle.

• Noise and lighting associated with vehicle traffic and developed areas, and fire suppression in close proximity to structures could adversely affect habitat for spotted owl over the long term.

In general, the ongoing effect of habitat degradation combined with continued visitor use and the foreseeable increase in visitors could result in a long-term (depending on specific effects on particular species), adverse effects to rare, threatened, and endangered species within the Merced River gorge.

Impacts in Wilderness Segments of the South Fork. No facilities (other than a few trails) currently occur in the upper and lower portions of the South Fork (above and below Wawona), 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 relatively inaccessible habitats. The only perceptible change anticipated under Alternative 1 could be an overall increase in visitors to the park that may increase pressure on relatively unused portions of the South Fork. Although increased visitor use of the upper and lower reaches of the South Fork could negatively affect habitats, these effects are considered speculative because topography would continue to limit the majority of visitors that can access these portions of the South Fork.

Impacts in Wawona. Under Alternative 1, habitats within the Wawona could continue to be affected by existing facilities and visitor use. Size, structure, productivity, and continuity (within habitat and between habitats) could continue to decrease due to conifer encroachment, visitor trampling, spread of non-native species, continued use of existing development, alteration of natural fire patterns (e.g., in the vicinity of historic structures), and loss of natural drainage patterns due to roads and diversions. Visitor use could continue to affect habitats of the central South Fork by compacting soils, reducing vegetative cover, altering streambanks, and inducing erosion, as described above. Roads, parking lots, and other impervious surfaces in or near the corridor could 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.

The following examples describe general actions and related adverse effects that could occur to rare, threatened, and endangered species along the South Fork. These effects are generally considered long term and adverse.

• Continued degradation of meadow and aquatic habitats coupled with an expected increase in visitors, could adversely affect species such as Wawona riffle beetle and willow flycatcher.

The South Fork includes nearly a full range of environments typical to the Sierra Nevada and supports numerous populations of rare plants and wildlife. Alternative 1 would likely have no effect on populations or individuals of these species.

Summary of Alternative 1 Impacts. Development and visitor activity in the Merced River corridor has affected rare, threatened, and endangered species. Implementation of Alternative 1 could continue to alter natural habitat and ecosystem patterns. The National Park Service would continue to implement existing goals and policies (e.g., the 1916 Organic Act, Yosemite Natural Resources Management Plan, Yosemite Vegetation Management Plan) and make incremental improvements on an ad-hoc basis, as opportunities and resource problems present themselves. For example, hampered by existing development and infrastructure, enhancement and re-establishment of woodlands could continue on a site-by-site basis rather than on a parkwide or Valleywide basis. Although substantial piecemeal improvements can take place given consistent under current direction, "reactive" resource management is not always effective at protecting of sensitive resources over the long term. Overall, effects to rare, threatened, and endangered species would be considered long-term and adverse. Effects could escalate as time passes and natural ecosystem patterns are not restored. These effects would be concentrated in areas of heavy visitor use such as Yosemite Valley. In areas of little use (e.g., a majority of the upper main stem of the Merced River and the upper and lower portions of the South Fork), continued use of existing facilities (e.g., trails) at a similar level of intensity would have little effect on rare, threatened, and endangered species.

Cumulative effects to rare, threatened, and endangered species discussed herein are based on analysis of past, present, and reasonably foreseeable actions in the Yosemite region. The intensity of impact depends on whether the impacts are anticipated to interact cumulatively. For example, factors external to the park, such as broad regional habitat degradation and pesticide use, can combine with existing, in-park impacts, such as non-native species, to cause declines in rare, threatened, or endangered amphibians (e.g., mountain yellow-legged frog and Yosemite toad), an adverse, cumulative impact. 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 beginning 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 Fellars 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 Sierra Nevada-wide amphibian declines; possible causes include habitat destruction, non-native fish, pesticides, and diseases. Past and ongoing activities that affect rare, threatened, or endangered species include construction of dams, diversion walls, bridges, roads, pipelines, riprap, recreational use, 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 non-motorized 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).

Present Actions. The El Portal Road Reconstruction Project (NPS) is currently underway from the park boundary to the Cascades Diversion Dam, and affects habitats immediately adjacent to the roadway. Special-status species with potential to be affected during construction include Valley elderberry longhorn beetle, roosting bats, peregrine falcon, and Tompkin's sedge. Special-status roosting bats could be affected, primarily through the noise generated by construction equipment and blasting. Blasting is also a concern for the peregrine falcon, known to occur at the Cascades aerie in the project vicinity (the peregrine was recently delisted but continues to be a species of concern in the park). Adverse effects to these species are avoided or minimized during construction by implementation of a compliance monitoring program, pre-construction surveys, erosion and sediment controls, minimizing noise during sensitive biological periods, construction timing restrictions, hazardous materials controls, revegetation and reclamation, and excluding construction from sensitive habitats. Such measures ensure the overall protection and enhancement of the hydrologic, biological, geologic, cultural, scenic, scientific, and recreation Outstandingly Remarkable Values in the zone as a whole and other parts of the river corridor. Implementation of these measures reduces the overall effects.

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 rare, threatened, or endangered species include:

• Several Yosemite campground rehabilitation projects, such as at Bridalveil Horse Camp, Yosemite Creek Campground, Tamarack Campground, Hodgdon Meadow Campground; and Wawona Campground Improvement (NPS)

• The Merced River at Eagle Creek Ecological Restoration Project (NPS)

• Update to the Yosemite Fire Management Plan (NPS), which has a goal of improving ecosystem health and meadow restoration

• Update to the Yosemite Wilderness Management Plan (NPS), which will address land management issues the wilderness

• Fire Management Action Plan for Wilderness (USFS, Stanislaus)

• The Sierra Nevada Framework for Conservation and Collaboration, and the Management Direction for the John Muir, Ansel Adams and Dinkey Lakes, and Monarch Wildernesses (USFS); Wilderness Boundary Protection Land Exchange, Seventh Day Adventist Camp, Wawona (NPS); each of which will address ecosystem management issues of lands adjacent to Yosemite National Park

• Several transportation-related projects (e.g., Yosemite Area Regional Transportation System [YARTS]) which have the general goals of increasing transportation options and reducing reliance on automobiles in the area

Although each of these projects may have slight site-specific 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, or endangered species. For example, the update to the Yosemite Wilderness Management Plan could result in the removal of the Merced Lake High Sierra Camp, reducing site-specific erosion and trampling and possibly stock use.

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

• The Tuolumne Meadows Development Concept Plan, and Tuolumne Wild and Scenic River Management Plan (NPS)

• The Tuolumne Meadows Water and Wastewater Improvements; the White Wolf Water System Improvements, Hodgdon Meadow Water and Wastewater Treatment Improvements, and Replacement/Rehabilitation of Yosemite Valley Sewer Line (NPS); O'Shaughnessy Compound Water System Improvements (City and Co. San Francisco)

• The Orange Crush Fuels Treatment Projects (USFS, Stanislaus)

• The A-Rock Reforestation (USFS, Stanislaus) and the Rogge-Ackerson Fire Reforestation (Tuolumne Co.)

• The Yosemite Valley Plan (NPS), which would implement the goals and actions of the 1980 General Management Plan (NPS)

• South Fork Merced River Bridges Replacement (NPS)

• South Entrance/Mariposa Grove Site Planning (NPS), which will restore giant sequoia habitat in the Lower Mariposa Grove of Giant Sequoias in Yosemite National Park

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 anticipate. For example, implementation of the Tuolumne Meadows Water and Wastewater Improvements project has the potential to adversely affect rare, threatened, and endangered species during construction (short-term), with the long-term, beneficial effect of improving water quality through improved wastewater treatment. Another example would be implementation of the Yosemite Valley Plan. Overall, implementation of this plan is expected to have a long-term, beneficial impact to rare, threatened, and endangered species by increasing coordinated management of natural resources and reducing facilities within sensitive habitats. However, short-term, adverse effects of this plan may include temporary construction impacts (e.g., potential reconstruction of Segment D of the El Portal Road Reconstruction Project just above Cascades Diversion Dam). Reconstruction of Segment D could cause short-term adverse impacts to natural resources similar to those currently occurring during reconstruction on Segments A, B, and C. These would include loss of mature (overstory) vegetation, loss of understory vegetation, impacts to special-status species, loss of topsoil, and footprint effects. 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 Outstandingly Remarkable Values of the Merced River) and implementation of best management practices, compliance monitoring, and restoration.

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

• The Yosemite View parcel land exchange, El Portal (NPS)

• Merced River Canyon Trail Acquisition (BLM)

• Several development related projects, such as the Rio Mesa Area Plan (Madera Co.); Yosemite Motels, El Portal (Mariposa Co.); Silvertip Resort Village Project (Mariposa Co.); University of California, Merced Campus (Merced Co.); Buildout of City of Merced, General Plan; Double Eagle Resort, June Lake (Mono Co.); Tioga Inn, Lee Vining (Mono Co.); June Lake Highlands (Mono Co.); Crane Flat Campus Redevelopment (NPS, YNI); Evergreen Lodge Expansion (Tuolumne Co.); Hardin Flat Lodging and Conference Facility (Tuolumne Co.); Motel and Restaurant, Second Garrotte Basin (Tuolumne Co.); Resources Management Building (NPS); Yosemite West Rezoning Application (NPS); and the Hazel Green Ranch (Mariposa Co.)

• Transportation projects, such as the Highway 41 Extension (Madera Co.); Yosemite Valley Shuttle Bus Stop Improvements (NPS); Road Realignment and Bridge Replacement at Highway 49 and Old Highway (Mariposa Co.); Expansion of Mariposa County Transit System; Mariposa Creek Pedestrian/Bike Path (Mariposa Co.); Evergreen Road Improvements (multi-agency, see Appendix G); and San Joaquin Corridor Rail Projects (DOT, Amtrak)

• Several water-related projects, such as the Replacement/Rehabilitation of Yosemite Valley Sewer Line (NPS); Cherry Dam Fuse Gate, and O'Shaughnessy Dam Well (City and Co. San Francisco)

Cumulative adverse effects would be related to increased facilities, access, and regional population growth. Each of the aforementioned projects has the potential to have substantial site-specific adverse effects on rare, threatened, and endangered species during construction (short-term) and by direct displacement of resources (long-term). The larger effect of these actions is related to population and regional growth and their subsequent effect on natural resources, including rare, threatened, and endangered species. Regional population growth primarily affects regional rare, threatened, and endangered species through construction (e.g., new housing and infrastructure) and visitor use. Examples of construction- and human-use-related effects on rare, threatened, and endangered species include direct displacement of rare, threatened, and endangered species (e.g., nest trees removed and replaced with structures), introduction of non-native species that invade into adjacent natural areas and displace native species (e.g., the spread of yellow star thistle by construction equipment and its subsequent adverse impacts on special status plant species), fragmentation of habitats that prevents genetic mixing, alteration of natural patterns (e.g., use of herbicides, the introduction of night light), and increased erosion and sedimentation (e.g., during grading activities, overuse of trails). Although each new development is required to mitigate or compensate for adverse effects to rare, threatened, and endangered species, the mitigation/compensation is generally uncoordinated and does not typically replace natural ecosystem functions or values that were present throughout the region prior to Euro-American settlement. In total, regional development and growth could have a net long-term, moderate to major (depending on species-specific impacts), adverse effect on regional rare, threatened, and endangered species that would not be compensated by regional planning and restoration projects discussed above.

Although cumulative actions could have a long-term, beneficial cumulative effect on rare, threatened, and endangered species and related Outstandingly Remarkable Values within the river corridor, throughout the Sierra Nevada and larger region, these past, present, and reasonably foreseeable future actions are likely to increase regional growth (construction and human-use-related effects) and have long-term, moderate to major (depending on species-specific impacts), adverse cumulative impacts on regional rare, threatened, and endangered species that would not be compensated by regional planning and restoration projects discussed above. These cumulative actions in combination with Alternative 1 could have a net long-term, adverse effect on regional rare, threatened, and endangered species.

Development and visitor activity in the Merced River corridor has affected rare, threatened, and endangered species. Implementation of Alternative 1 could continue to alter natural habitat and ecosystem patterns. The National Park Service would continue to implement existing goals and policies (e.g., the 1916 Organic Act, Yosemite Natural Resources Management Plan, Yosemite Vegetation Management Plan) and make incremental improvements on an ad-hoc basis, as opportunities and resource problems present themselves. For example, hampered by existing development and infrastructure, enhancement and re-establishment of woodlands could continue on a site-by-site basis rather than on a parkwide or Valleywide basis. Although substantial piecemeal improvements can take place given consistent under current direction, "reactive" resource management is not always effective at protecting of sensitive resources over the long term. Overall, effects to rare, threatened, and endangered species would be considered long-term and adverse. Effects could escalate as time passes and natural ecosystem patterns are not restored. These effects would be concentrated in areas of heavy visitor use such as Yosemite Valley. In areas of little use (e.g., a majority of the upper main stem of the Merced River and the upper and lower portions of the South Fork), continued use of existing facilities (e.g., trails) at a similar level of intensity would have little effect on rare, threatened, and endangered species.

Although cumulative actions could have a long-term, beneficial cumulative effect on rare, threatened, and endangered species and related Outstandingly Remarkable Values within the river corridor, throughout the Sierra Nevada and larger region, these past, present, and reasonably foreseeable future actions are likely to increase regional growth (construction and human-use-related effects) and have long-term, moderate to major (depending on species-specific impacts), adverse cumulative impacts on regional rare, threatened, and endangered species that would not be compensated by regional planning and restoration projects discussed above. These cumulative actions in combination with Alternative 1 could have a long-term, adverse effect on regional rare, threatened, and endangered species.

Air Quality

Analysis

General Impacts. Under Alternative 1, air quality would continue to be listed as an Outstandingly Remarkable Value along all segments of the main stem and South Fork of the Merced River in the park, but not the El Portal Administrative Site; however, no policies that protect or enhance air quality along these segments have been developed as a direct result of such listing. Policies and actions that protect and enhance air quality in the corridor arise not from the Wild and Scenic Rivers Act but from such laws as the federal Clean Air Act.

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. 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 the 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.

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.

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 and near Wawona under certain meteorological conditions. Emissions from prescribed burning would continue to be controlled through implementation of smoke management policies in the 1990 Fire Management Plan; these policies are intended to minimize impacts on air quality from prescribed burning within the park and region. 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. 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 the Valley on typically busy days would be essentially the same as under existing conditions since, on those days, the Restricted Access Plan would be in effect; 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. As a general matter, the downward trend in emissions of ozone precursors per vehicle would more than offset the 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 80% for volatile organic compounds and 50% for nitrogen oxides between existing conditions and 2020. 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 in the future in rough proportion to the number of vehicle-miles-traveled within the Valley.

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, non-wilderness 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, which would represent a long-term, regional, beneficial effect. With respect to particulate matter, overall local emissions under Alternative 1 could increase relative to existing conditions, resulting in a long-term, adverse effect, since that pollutant is more closely linked to overall vehicle-miles-traveled, which would increase, than to tailpipe exhaust emissions, which would decrease.

Cumulative effects to air quality discussed herein 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 six-fold. Air quality conditions within the 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, a Restricted Access Plan was developed for use when traffic and parking conditions in Yosemite Valley are overcongested. The plan has 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.

The 1990 Fire Management Plan was developed to address management issues related to prescribed natural burns, prescribed burns, and wildfires in the park. Implementation of the smoke management policies of the 1990 Fire Management Plan reduces the potential for burns or wildfires to have a major effect on air quality in the park or in the park vicinity.

Present Actions. The El Portal Road Reconstruction Project (NPS) is currently underway and has both negative (short-term during construction) and potentially beneficial (long-term) effects on air quality. Short-term, construction-related effects include dust and other pollutant emissions associated with operation of construction equipment, earthmoving activities, and vehicle travel over unpaved surfaces. Current safety improvements on Segments A, B, and C of El Portal Road would facilitate regional transit service on that route, which could have a long-term, beneficial impact by reducing automobile trips.

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 not anticipated to have a net adverse or beneficial, long-term effect.

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

• The Yosemite Area Regional Transportation System (YARTS) is a collaborative, multiagency effort to evaluate the feasibility of a regional transportation system and to determine the organizational structure of an entity that would implement and operate the system. The intent of YARTS is to provide an attractive alternative to private vehicles by expanding the range of travel options for visitors to Yosemite Valley and to other primary park destinations, and for employees commuting to work in the park.

• The San Joaquin Corridor Rail Projects (DOT, Amtrak) would contribute to a long-term, beneficial impact on air quality because such improvements would encourage travel by alternative (non-private vehicle) modes, particularly if combined with the potential expansion of regional transit service proposed by YARTS.

• The Yosemite West Rezoning Application (NPS) and the Resources Management Building (NPS) are two projects that would reduce work/home commutes for some employees.

• The Yosemite Valley Plan (NPS) 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.

• The Yosemite Valley Plan (NPS) also includes safety improvements on Segment D of the El Portal Road Reconstruction Project (i.e., the segment from Cascades Diversion Dam [near the El Portal Road/Big Oak Flat Road intersection] to the Pohono Bridge). Construction activity on Segment D would cause short-term, major, adverse impacts on local air quality primarily due to dust from construction activities, similar to those currently occurring during construction on Segments A, B, and C. Those adverse impacts associated with Segment D construction activity could be mitigated by implementation of best management practices. Safety improvements on Segment D of El Portal Road, together with improvements on Segments A, B, and C, would facilitate expanded regional transit service on that route, and expanded transit could lead to fewer vehicles and less vehicle emissions.

• Several other regional projects that will have a net beneficial effect on air quality by improving the relative attractiveness of alternative modes of transportation and thereby reducing private automobile vehicle trips include the Yosemite Valley Shuttle Bus Stop Improvements (NPS) and the Expansion of Mariposa County Transit System.

Although most of the aforementioned projects would have localized, short-term adverse effects (e.g., construction-related effects), the general goal of each of these projects is to improve regional transportation, circulation, and safety. As such, these projects would, individually and in combination, encourage travel to the park by alternative (non-private vehicle) modes and would have a beneficial, long-term effect on air quality.

Reasonably foreseeable future actions that could have an adverse effect on air quality include:

• Revisions to the 1990 Yosemite Fire Management Action Plan and development of the U.S. Forest Service's Fire Management Action Plan for Wilderness, which could lead to increased use of prescribed burning techniques

• Forest-related projects, such as the Orange Crush Fuels Treatment Projects the A-Rock Reforestation, the Fire Management Action Plan for Wilderness (USFS, Stanislaus), and the Rogge-Ackerson Fire Reforestation (Tuolumne Co.)

• The Wawona Campground Improvement (NPS)

• Various development-related projects such as the Mariposa County General Plan Update; Hazel Green Ranch (Mariposa Co.); Rio Mesa Area Plan (Madera Co.); Yosemite Motels, El Portal (Mariposa Co.); Silvertip Resort Village Project (Mariposa Co.); University of California, Merced Campus (Merced Co.); and the Buildout of City of Merced, General Plan

• The Highway 41 Extension (Madera Co.), which would not be a land use development project but would remove an obstacle to land use development (and associated emissions) in the fast-growing area north of Fresno

Revisions to 1990 Yosemite Fire Management Plan, the development of the Fire Management Action Plan for Wilderness (USFS, Stanislaus), and the fuels and reforestation projects 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 upon the extent to which these projects protect air resources. The Wawona Campground Improvement (NPS) would construct additional campsites, which could result in increased local emissions from campfires, unless the overall project (which would also involve rehabilitation of an existing campground) provides for group fire rings, rather than fire rings at each campsite.

Cumulative growth in the region, and the transportation projects such as the Highway 41 Extension (Madera Co.) that support cumulative growth, 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 Replacement/Rehabilitation of Yosemite Valley Sewer Line (NPS); and South Fork Merced River Bridges Replacement (NPS)

• Several Yosemite campground rehabilitation and resource restoration projects and plans, such as Merced River at Eagle Creek Ecological Restoration Project (NPS); update to the Yosemite Wilderness Management Plan (NPS); Tamarack Campground Rehabilitation (NPS); Bridalveil Horse Camp Rehabilitation (NPS); Yosemite Creek Campground Rehabilitation (NPS); and the South Fork and Merced Wild and Scenic River Implementation Plan (USFS, BLM)

• Land exchanges, such as Yosemite View Parcel Land Exchange, El Portal (NPS) and Wilderness Boundary Protection Land Exchange, Seventh Day Adventist Camp, Wawona (NPS)

Many of the above 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 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, 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, since 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, adverse cumulative 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 on going state and federal mobile-source control programs. With respect to particulate matter, conditions in the 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, the opposing emissions trends would tend to diminish the magnitude of the effect, regardless of whether the effect would be beneficial or adverse.

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, non-wilderness 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, which would represent a long-term, regional, beneficial effect. With respect to particulate matter, overall local emissions under Alternative 1 could increase relative to existing conditions, resulting in a long-term, adverse effect, since that pollutant is more closely linked to overall vehicle-miles-traveled, which would increase, than to tailpipe exhaust emissions, which would decrease.

Since Alternative 1 would not involve any substantial construction projects, the local, short-term, adverse cumulative 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 corridor would be determined by both regional sources and local sources, and the relative influence of these two types of sources would vary on a daily and seasonal basis. 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, the opposing emissions trends would tend to diminish the magnitude of the effect, regardless of whether the effect would be beneficial or adverse.

Noise

Analysis

General Impacts. Under this alternative, "natural quiet" would continue to be listed as an Outstandingly Remarkable Value along the wilderness segment of the main stem of the Merced River, and the wilderness and "below Wawona" segments of the South Fork. However, no policies that protect and enhance natural quiet along these segments have been developed as a direct result of such listing. Policies and actions that protect and enhance natural quiet in the corridor arise not from the Wild and Scenic Rivers Act but from such plans as the 1989 Wilderness Management Plan.

Under Alternative 1, the acoustical environment in wilderness areas would continue to be shaped largely by natural sources of sound punctuated by intrusive noise generated by high-altitude aircraft overflights. In some wilderness areas, such overflights would continue to be the principal source of adverse noise impacts. The permit system under the Wilderness Management Plan would continue to minimize the noise associated with visitor use in wilderness by restricting the number of overnight visitors. In contrast, noise from high-altitude aircraft overflights, which is an issue that is national in scope, will likely worsen over the long term, given the upward national trend in the number of aircraft flights.

The acoustical environment in non-wilderness areas would 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. 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. The gradual increase in visitation and related vehicular traffic would lead to an incremental increase in roadside noise levels. On typically busy days, when the Restricted Access Plan would be in effect, 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. In both wilderness and non-wilderness areas, 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, 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 non-wilderness areas would 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. Alternative 1 would accommodate a gradual increase in annual visitation, which would lead to a local, long-term, adverse effect along the various roads that traverse the corridor in non-wilderness areas.

Cumulative effects to the ambient noise environment discussed herein 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 National Park Service has adopted two plans, a Restricted Access Plan and the Wilderness Management Plan, that indirectly affect overall noise levels in the river corridor. The Restricted Access Plan was developed for use when traffic and parking conditions in Yosemite Valley are overcongested. 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.

Present Actions. The El Portal Road Reconstruction Project (NPS) is currently underway and has both adverse (short-term during construction) and beneficial (long-term) effects on noise. Short-term, construction-related effects include noise from heavy equipment operations. Current safety improvements on Segments A, B, and C of El Portal Road would facilitate regional transit service on that route, which may have a long-term, beneficial impact on roadside noise levels by replacing automobile trips with a fewer number of transit vehicles trips, depending upon transit ridership levels and the technology used for transit vehicles.

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:

• The Yosemite Area Regional Transportation System (YARTS) is a collaborative, multiagency effort to evaluate the feasibility of a regional transportation system and to determine the organizational structure of an entity that would implement and operate the system. The intent of YARTS is to provide an attractive alternative to private vehicles by expanding the range of travel options for visitors to Yosemite Valley and to other primary park destinations, and for employees commuting to work in the park.

• Passenger rail improvements in the Amtrak San Joaquin Corridor (DOT, Amtrak) and potential creation of high-speed rail service would encourage travel by alternative (nonprivate vehicle) modes, particularly if combined with the potential expansion of regional transit service proposed by YARTS.

• The Yosemite West Rezoning Application (NPS) and the Resources Management Building (NPS) are two projects that would reduce in-Valley vehicle trips for some employees.

• The Yosemite Valley Plan (NPS) 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.

• The Yosemite Valley Plan (NPS) also includes safety improvements on Segment D of the El Portal Road Improvement Project (i.e., the segment from Cascades Diversion Dam [near the El Portal Road/Big Oak Flat Road intersection] to the Pohono Bridge). Construction activity on Segment D would cause short-term adverse impacts on the local noise environment primarily due to construction activities, similar to those currently occurring during construction on Segments A, B, and C. Those adverse impacts associated with Segment D construction activity could be mitigated by implementation of best management practices. Safety improvements on Segment D of El Portal Road, together with improvements on Segments A, B, and C, would facilitate expanded regional transit service on that route, and expanded transit could lead to fewer vehicles and less vehicle noise.

• Several other regional transportation projects that would have a net beneficial effect on noise by improving the relative attractiveness of alternative modes of transportation and thereby reducing private automobile vehicle trips include the Yosemite Valley Shuttle Bus Stop Improvements (NPS), and the Expansion of Mariposa County Transit System (Mariposa Co.).

• Update to the National Park Service's 1989 Yosemite Wilderness Management Plan.

Although most of the aforementioned projects would have localized, short-term, adverse effects (e.g., construction-related effects), the general goal of each of these projects is to improve regional transportation, circulation, and safety. As such, these projects would, individually and in combination, encourage travel to the park by alternative (non-private vehicle) modes and would therefore have a beneficial, long-term effect on the ambient noise environment.

To the extent that the transportation-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) and the technology selected for the buses. While a bus generates higher maximum noise levels than an automobile, a shift from auto to bus trips would reduce average roadside noise levels, assuming a certain number of auto trips would be displaced. For instance, a typical diesel-powered bus generates the same amount of noise as approximately 6 to 50 typical automobiles at speeds of 40 miles per hour or less (the difference between bus and auto noise is inversely related to speed), based on data compiled by the U.S. Department of Transportation (FHWA 1995). Assuming that a typical electric bus generates approximately 6 dBA less than a typical diesel bus, an electric bus generates the same amount of noise as approximately 2 to 13 typical automobiles. 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 a combination of low ridership levels and typical diesel bus technology.

Implementation of an update to the Yosemite Wilderness Management Plan (NPS) would have a net beneficial, long-term effect on the ambient noise environment in the Merced River corridor because of the emphasis on improving visitor use management as it relates to naturally functioning ecosystems and a quality diverse wilderness experience.

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

• Various development-related projects, such as the Mariposa County General Plan Update (Mariposa Co.); Hazel Green Ranch (Mariposa Co.); Rio Mesa Area Plan (Madera Co.); Yosemite Motels, El Portal (Mariposa Co.); University of California, Merced Campus (Merced Co.); Buildout of City of Merced, General Plan

• Wawona Campground Improvement (NPS)

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. The Wawona Campground Improvement (NPS) would construct additional campsites, which may result in increased noise in Section 35.

Cumulative projects 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 Replacement/Rehabilitation of Yosemite Valley Sewer Line; and South Fork Merced River Bridges Replacement (NPS)

• Several Yosemite campground rehabilitation and resource restoration projects and plans, such as Merced River at Eagle Creek Ecological Restoration, Bridalveil Horse Camp Rehabilitation; and Yosemite Creek Campground Rehabilitation (NPS)

• Land exchanges, such as Yosemite View Parcel Land Exchange, El Portal (NPS) and Wilderness Boundary Protection Land Exchange, Seventh Day Adventist Camps, Wawona (NPS)

Many of the above cumulative projects would result in local, short-term, 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, minor, long-term adverse effect in some portions of the corridor in wilderness areas due to increased aircraft overflights and associated intrusive noise levels. In non-wilderness 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, minor, long-term, beneficial effect within the corridor depending upon the type of technology used for transit purposes and 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, 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 would result in a local, long-term, adverse effect on the ambient noise environment. In non-wilderness 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, adverse effect on noise levels in those portions of the corridor through which roadways traverse.

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 non-wilderness areas would 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. Alternative 1 would accommodate a gradual increase in annual visitation, which would lead to a local, long-term, adverse effect along the various roads that traverse the corridor in non-wilderness areas.

Since Alternative 1 would not involve any substantial construction projects, the local, short-term, 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 would result in a local, long-term, adverse effect on the ambient noise environment. In non-wilderness 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, adverse effect on noise levels in those portions of the corridor through which roadways traverse.

Cultural Resources

Archeological Resources

Analysis

General Impacts. The following discussion provides an overview of the types of archeological resource impacts that could occur within the Merced River corridor from application of Alternative 1.

Under Alternative 1, there would be no change in management and treatment of archeological sites in the Merced River corridor. Therefore, impacts to archeological resources would occur only as a result of ongoing park operations and programs, such as facilities maintenance and repair. These actions have the potential to disturb intact archeological resources, which are identified as an Outstandingly Remarkable Value. Since the intensity of impacts would depend upon the nature, location, and design of the undertaking as well as the quantity and data potential of the archeological site(s) affected, it is not possible to determine the intensities of those impacts. These actions would be subject to site-specific planning and compliance and would be undertaken in accordance with stipulations in the park's 1999 Programmatic Agreement (Advisory Council on Historic Preservation 1999). Every effort would be made during the design phase to avoid adverse impacts. Where such avoidance were not feasible or prudent, the park would implement data recovery excavations to retrieve important scientific information, thereby reducing the intensity of the impact.

Summary of Alternative 1 Impacts. There would be no change in the treatment and management of archeological resources as a result of Alternative 1. Any site-specific planning and compliance actions would be accomplished in accordance with stipulations in the park's 1999 Programmatic Agreement.

Cumulative impacts to archeological resources discussed herein 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 archeological resources within the river corridor.

Past Actions. Archeological resources are subject to damage from development, vandalism, visitor access, and natural processes. For example, the 1997 flood exposed portions of two archeological resources in El Portal.

In general, the 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.

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 non-motorized 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).

Present Actions. There are archeological resource sites in Yosemite Valley, El Portal, and Wawona that are considered to be at risk from 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.

Reasonably Foreseeable Future Actions. Reasonably foreseeable future actions proposed in the region that could have a cumulative effect on archeological resources in the vicinity include:

• Several Yosemite campground rehabilitation projects, such as at Bridalveil Horse Camp, Yosemite Creek Campground, Tamarack Campground, Wawona Campground, and Hodgdon Meadow Campground (NPS)

• The Merced River at Eagle Creek Ecological Restoration Project (NPS)

• Update to the Yosemite Wilderness Management Plan (NPS)

• The Yosemite Valley Plan (NPS)

• Several transportation-related projects (e.g., Yosemite Area Regional Transportation System), which have the general goals of increasing transportation options and reducing reliance on automobiles in the area

• South Entrance/Mariposa Grove Site Planning (NPS)

• Resources Management Building, Yosemite West Rezoning Application, South Fork Merced River Bridges Replacement (NPS)

• Tuolumne Meadows Development Concept Plan, and Tuolumne Wild and Scenic River Management Plan (NPS)

• Several water improvement projects, such as the Tuolumne Meadows Water and Wastewater Improvements, the White Wolf Water System Improvements, Hodgdon Meadow Water and Wastewater Treatment Improvements, Replacement/Rehabilitation of Yosemite Valley Sewer Line (NPS), Cherry Dam Fuse Gate, O'Shaughnessy Dam Well, and O'Shaughnessy Compound Water System Improvements (City and Co. of San Francisco)

• Orange Crush Fuels Treatment Projects (USFS, Stanislaus)

• Various development-related projects, such as the Yosemite View parcel land exchange, El Portal (NPS); Wilderness Boundary Protection Land Exchange, Seventh Day Adventist Camp, Wawona (NPS), Hazel Green Ranch (Mariposa Co.), Crane Flat Campus Redevelopment (NPS, YNI), Rio Mesa Area Plan (Madera Co.); Yosemite Motels, El Portal (Mariposa Co.); Silvertip Resort Village Project (Mariposa Co.); University of California, Merced Campus (Merced Co.); Buildout of City of Merced General Plan; Double Eagle Resort, June Lake (Mono Co.); Tioga Inn, Lee Vining (Mono Co.); June Lake Highlands (Mono Co.); Evergreen Lodge Expansion (Tuolumne Co.); Hardin Flat Lodging and Conference Facility (Tuolumne Co.); Motel and Restaurant, Second Garrotte Basin (Tuolumne Co.); Resources Management Building (NPS); Yosemite West Rezoning Application (NPS); and the Hazel Green Ranch (Mariposa Co.)

• Transportation projects, such as the Highway 41 Extension (Madera Co.); Yosemite Valley Shuttle Bus Stop Improvements (NPS); South Fork Merced River Bridges Replacement (NPS); Road Realignment and Bridge Replacement of Highway 49 and Old Highway (Mariposa Co.); Expansion of Mariposa County Transit System; Mariposa Creek Pedestrian/Bike Path (Mariposa Co.); Evergreen Road Improvements (multi-agency, see Appendix G); San Joaquin Corridor Rail Projects (DOT, Amtrak)

• Merced River Canyon Trail Acquisition (BLM)

The extensive grading and ground disturbance that could be required for these cumulative projects could disturb individual archeological resources. Each of these cumulative projects is within an archeologically sensitive area, such as a river valley or a mountain meadow. Any disturbance of an individual archeological resource is likely to have a long-term, moderate to major, adverse impact, with the intensity of the impact subject to design and final locations of proposed facilities.

Alternative 1 and the cumulative projects within and in the vicinity of Yosemite National Park would result in a long-term, adverse impact on archeological resources. The intensity of the impact would depend upon design and final locations of proposed facilities.

There would be no change in the treatment and management of archeological resources as a result of Alternative 1. Any site-specific planning and compliance actions would be accomplished in accordance with stipulations in the park's 1999 Programmatic Agreement.

Alternative 1 and the cumulative projects within and in the vicinity of Yosemite National Park would result in a long-term, adverse impact on archeological resources. The intensity of the impact would depend upon design and final locations of proposed facilities.

Ethnographic Resources

Analysis

General Impacts. The following discussion provides an overview of the types of ethnographic resource impacts that could occur within the Merced River corridor from application of Alternative 1.

Under Alternative 1, there would be no change in management and treatment of ethnographic resources in the Merced River corridor. Therefore, impacts to ethnographic resources would occur only as a result of ongoing park operations and programs, such as facilities maintenance and repair. Since the intensity of impact depends upon the nature, location, and design of the undertaking, as well as the quantity and nature of ethnographic resource(s) affected, it is not possible to determine the intensities of those impacts. These actions would be subject to site-specific planning and compliance and would be undertaken in accordance with stipulations in the park's 1999 Programmatic Agreement (Advisory Council on Historic Preservation 1999). The park would continue to consult with culturally associated Indian tribes under this Programmatic Agreement and the cooperative agreement for traditional uses. Every effort would be made during the design phase to avoid adverse impacts. Where such avoidance were not feasible or prudent, the park, in consultation with culturally associated Indian tribes, would mitigate the impacts to the greatest extent possible, potentially reducing the intensity of the impacts. Mitigation could include identification of and assistance in providing access to alternative resource gathering areas, continuing to provide access to traditional use and spiritual areas, and screening new development from traditional use areas.

Summary of Alternative 1 Impacts. There would be no change in the treatment and management of ethnographic resources as a result of Alternative 1. Any site-specific planning and compliance actions would be accomplished in accordance with stipulations in the park's 1999 Programmatic Agreement, and the park would continue to consult with culturally associated Indian tribes under this Programmatic Agreement and the cooperative agreement for traditional uses.

Cumulative impacts to ethnographic resources discussed herein are based on analysis of past, present, and reasonably foreseeable actions in the Yosemite region in combination with potential effects of this alternative.

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

In general, the ethnographic 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 ethnographic resources and compromised the integrity of numerous other such resources.

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 non-motorized 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).

Present Actions. No present actions have been identified that would affect ethnographic resources in the Merced River corridor.

Reasonably Foreseeable Future Actions. Reasonably foreseeable future actions proposed in the region are separated below into two general categories: (1) projects that could adversely affect ethnographic resources; and (2) projects that could beneficially affect ethnographic resources.

Examples of projects that could have a cumulative, adverse effect on ethnographic resources in the region include:

• Several Yosemite campground rehabilitation projects, such as at Bridalveil Horse Camp, Yosemite Creek Campground, Tamarack Campground, Wawona Campground, and Hodgdon Meadow Campground (NPS)

• The Yosemite Valley Plan (NPS)

• Several water improvement projects, such as the Tuolumne Meadows Water and Wastewater Improvements, the White Wolf Water System Improvements, Hodgdon Meadow Water and Wastewater Treatment Improvements, Replacement/Rehabilitation of Yosemite Valley Sewer Line (NPS), Cherry Dam Fuse Gate, O'Shaughnessy Dam Well, and O'Shaughnessy Compound Water System Improvements (City and Co. of San Francisco)

• The Orange Crush Fuels Treatment Projects (USFS, Stanislaus)

• Transportation projects, such as the Highway 41 Extension (Madera Co.); Yosemite Valley Shuttle Bus Stop Improvements (NPS); South Fork Merced River Bridges Replacement (NPS); Road Realignment and Bridge Replacement of Highway 49 and Old Highway (Mariposa Co.); Expansion of Mariposa County Transit System; Mariposa Creek Pedestrian/Bike Path (Mariposa Co.); Evergreen Road Improvements (multi-agency, see Appendix G); San Joaquin Corridor Rail Projects (DOT, Amtrak)

• Various development-related projects such as, the Yosemite View parcel land exchange, El Portal (NPS); Rio Mesa Area Plan (Madera Co.); Yosemite Motels, El Portal (Mariposa Co.); Silvertip Resort Village Project (Mariposa Co.); University of California, Merced Campus (Merced Co.); Buildout of City of Merced General Plan; Double Eagle Resort, June Lake (Mono Co.); Tioga Inn, Lee Vining (Mono Co.); June Lake Highlands (Mono Co.); Evergreen Lodge Expansion (Tuolumne Co.); Hardin Flat Lodging and Conference Facility (Tuolumne Co.); Motel and Restaurant, Second Garrotte Basin (Tuolumne Co.); Hazel Green Ranch (Mariposa Co.); and Resources Management Building (NPS)

• Merced River Canyon Trail Acquisition (BLM)

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

Reasonably foreseeable projects that would beneficially affect ethnographic resources in the Merced River corridor include:

• The Merced River at Eagle Creek Ecological Restoration Project (NPS)

• Update to the Yosemite Wilderness Management Plan, which will address land management issues within the wilderness (NPS)

• Update to the Yosemite Fire Management Plan, which has a goal of improving ecosystem health and meadow restoration (NPS)

• The Sierra Nevada Framework for Conservation and Collaboration, and the Management Direction for the John Muir, Ansel Adams and Dinkey Lakes, and Monarch Wildernesses (USFS), both of which will address ecosystem management issues of Forest Service lands adjacent to Yosemite National Park

• Fire Management Action Plan for Wilderness (USFS, Stanislaus)

• The Pinecrest Basin Forest Plan Amendment (USFS, Stanislaus)

• A-Rock Reforestation (USFS, Stanislaus) and the Rogge-Ackerson Fire Reforestation (Tuolumne Co.)

These cumulative projects could result in restoration of native plant habitat, which would be a long-term, beneficial impact on ethnographic resources. The intensity of this impact would depend on the extent to which gathering sites were restored and access to traditional use places were continued.

The cumulative projects within and in the vicinity of Yosemite National Park would result in a long-term, minor, beneficial impact on ethnographic 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 long-term, adverse impacts associated with damaging gathering sites or restricting access to traditional use places.

Alternative 1 and the cumulative projects within and in the vicinity of Yosemite National Park would result in a long-term, beneficial impact on ethnographic resources. The intensity of the impact would depend upon the extent of the management of natural resources and river processes.

There would be no change in the treatment and management of ethnographic resources as a result of Alternative 1. Any site-specific planning and compliance actions would be accomplished in accordance with stipulations in the park's 1999 Programmatic Agreement, and the park would continue to consult with culturally associated Indian tribes under this Programmatic Agreement and the cooperative agreement for traditional uses.

Alternative 1 and the cumulative projects within and in the vicinity of Yosemite National Park would result in a long-term, beneficial impact on ethnographic resources. The intensity of the impact would depend upon the extent of the management of natural resources and river processes.

The following discussion provides an overview of the types of cultural landscape resource impacts that could occur within the Merced River corridor from application of Alternative 1.

All cultural landscape resources, historic sites, and structures would continue to be managed as they are today. Therefore, impacts to cultural landscape resources would occur only as a result of ongoing park operations and programs, such as facilities maintenance and repair. These actions have the potential to adversely affect historic resources, which are classified as an Outstandingly Remarkable Value. Impacts would be associated with maintenance activities that remove historic fabric, remove historic structures, or add incompatible facilities within or adjacent to historic structures. The intensity of impact would depend upon the nature, location, and design of the undertaking, measurable change in character-defining features of a historic property, and the number of contributing elements of a historic district that are affected. These actions would be subject to site-specific planning and compliance and would be undertaken in accordance with stipulations in the park's 1999 Programmatic Agreement. Every effort would be made during the design phase to avoid adverse impacts. These efforts could include screening and/or sensitive design that would be compatible with cultural landscape resources. Should avoidance of adverse impacts not be possible, documentation and treatment stipulated in the 1999 Programmatic Agreement would reduce the intensity of the impact.

There would be no change in the treatment and management of cultural landscape resources as a result of Alternative 1. Any site-specific planning and compliance actions would be accomplished in accordance with stipulations in the park's 1999 Programmatic Agreement.

Cumulative impacts to cultural landscape resources discussed herein are based on analysis of past, present, and reasonably foreseeable actions in the Yosemite region in combination with potential effects of this alternative.

Past Actions. Cultural landscape resources have been lost or damaged in Yosemite through past development, visitor use, and natural events. In wilderness areas, cultural 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 structures associated with hydropower generation. 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.

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 non-motorized 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).

Present Actions. The El Portal Road Reconstruction Project (NPS) is currently underway and affects cultural landscape resources within the Merced River gorge. Cultural landscape resources are protected during construction by implementation of a compliance monitoring program.

Reasonably Foreseeable Future Actions. Reasonably foreseeable future actions proposed in the region that could affect cultural landscape resources include:

• Several Yosemite campground rehabilitation projects, such as at Bridalveil Horse Camp, Yosemite Creek Campground, Tamarack Campground, Wawona Campground, and Hodgdon Meadow Campground (NPS)

• The Yosemite Valley Plan (NPS), which would implement the goals and actions of the 1980 General Management Plan

• Several transportation-related projects (e.g., Yosemite Area Regional Transportation System (YARTS)), which have the general goals of increasing transportation options and reducing reliance on automobiles in the area

• The Merced River at Eagle Creek Ecological Restoration Project (NPS)

• The Update to the Yosemite Wilderness Management Plan, which will address land management issues within the wilderness

• Several water improvement projects, such as Replacement/Rehabilitation of Yosemite Valley Sewer Line (NPS); Cherry Dam Fuse Gate, O'Shaughnessy Dam Well, and O'Shaughnessy Compound Water System Improvements (City and Co. of San Francisco)

• Merced River Canyon Trail Acquisition (BLM)

• Update to the Yosemite Fire Management Plan (NPS), which has a goal of improving ecosystem health and meadow restoration

Given that each of these actions could result in removal of historic fabric or resources, add noncontributing elements to the historic cultural landscape, or add incompatible facilities within or adjacent to a cultural landscape resource, these cumulative projects would have a long-term, minor to major, adverse impact on cultural landscape resources. The impact intensity of any planning projects would depend upon the extent to which the plan's recommendations were implemented.

Alternative 1 and the cumulative projects within and in the vicinity of Yosemite National Park would result in a long-term, adverse impact on cultural landscape resources. The intensity of the impact would depend upon the nature, location, and design of the undertaking, measurable change in character-defining features of a historic property, and the number of contributing elements of a historic district that were affected.

There would be no change in the treatment and management of cultural landscape resources as a result of Alternative 1. Any site-specific planning and compliance actions would be accomplished in accordance with stipulations in the park's 1999 Programmatic Agreement.

Alternative 1 and the cumulative projects within and in the vicinity of Yosemite National Park would result in a long-term, adverse impact on cultural landscape resources. The intensity of the impact would depend upon the nature, location, and design of the undertaking, measurable change in character-defining features of a historic property, and the number of contributing elements of a historic district that were affected.

Under regulations of the Advisory Council on Historic Preservation (36 Code of Federal Regulations 800.9) that address the criteria of effect and adverse effect, the National Park Service has determined that selection of this alternative would result in "no effect" to historic properties listed in or eligible for listing in the National Register of Historic Places. The California State Historic Preservation Officer has concurred with this determination.

Visitor Experience

Recreation

Analysis

General Impacts. The following discussion provides an overview of the types of visitor experience impacts that could occur within the Merced River corridor from application of Alternative 1.

Impacts in Wilderness. There would be no changes regarding access to campgrounds in the wilderness under this alternative. Existing facilities within wilderness segments of the Merced River corridor reflect current management practices and use levels based on the Wilderness Act and federal and Yosemite National Park wilderness policies and guidelines. Outstandingly Remarkable Values within wilderness segments include the pristine wilderness, and travel and camping in Little Yosemite Valley and at Merced and Washburn Lakes. These Outstandingly Remarkable Values would not be affected by this alternative.

Impacts in Yosemite Valley. Under the No Action Alternative, some activities could become more crowded because of an ongoing, long-term increase in the park's overall visitation. As a result, the characteristics of these activities could change. For example, fishing could become a more social experience as opposed to a solitary experience in certain parts of the river corridor. Changes in the quality of the experience would vary by recreational opportunity and location within the river corridor. Although a full range and diversity of recreational opportunities would still be available to visitors, there could be a local, long-term,adverse impact associated with recreation under Alternative 1 due to a continuing deterioration of the quality of the visitor experience.

Outstandingly Remarkable Values within Yosemite Valley include hiking, picnicking, camping, climbing, skiing, fishing, photography, swimming, nature study, horseback riding, biking, sightseeing, and boating. Continuing degradation of the quality of some of these Outstandingly Remarkable Values is considered to be a long-term, adverse impact under this alternative.

Impacts in the Merced River Gorge and El Portal. Recreation within the Merced River gorge and El Portal would remain consistent with existing conditions. In El Portal, people swim at Patty's Hole and near the sand pit. Fishermen access the river from the sand pit, as well as between Patty's Hole and the sand pit. These areas would not be affected.

Outstandingly Remarkable Values within the Merced River gorge and El Portal include picnicking, climbing, fishing, photography, sightseeing, and white-water use. These Outstandingly Remarkable Values would not be affected under this alternative.

Impacts in Wawona. Recreational use of Wawona would remain similar to existing conditions. Outstandingly Remarkable Values within Wawona include hiking, picnicking, camping, skiing, fishing, photography, swimming, nature study, horseback riding, biking, sightseeing, and boating. These Outstandingly Remarkable Values would not be affected under this alternative.

Summary of Alternative 1 Impacts. Under Alternative 1, availability and diversity of recreational opportunities in the river corridor would continue as presently managed. Activities such as the use of non-motorized watercraft (e.g., rafts, inner tubes, kayaks), swimming and wading, hiking, backpacking, camping, rock climbing, fishing, sightseeing, photography, nature study, bicycling, and stock use would continue to be available at existing levels. Trails and campgrounds within the corridor would be maintained in their current locations. Alternative 1 therefore would have no impact on recreation in Yosemite National Park. The river environment would continue to degrade, and this continuing degradation would have a long-term, adverse effect on the quality of the riverine environment for recreational activities.

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 vicinity.

Past Actions. 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 non-motorized watercraft. Implementation of these actions would have 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 (e.g., restrooms) that mitigate adverse effects associated with visitor use.

Present Actions. The El Portal Road Reconstruction Project (NPS) is currently underway and has both adverse (short-term during construction) and beneficial (long-term) effects on visitor experience. Short-term, construction-related effects include travel delay and closure of the area to recreational use. Those effects are mitigated by implementation of a traffic control plan with measures such as strict construction timing restrictions, roadway safety procedures, and the use of flaggers, and signals. Long-term effects are improved access to recreational opportunities along the river corridor and El Portal Road, and easier, more dependable, and safer access for recreational vehicles, buses, and other vehicles to Yosemite Valley and other park destinations.

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 a net adverse effect.

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

• The Yosemite Area Regional Transportation System (YARTS)

• The Merced River at Eagle Creek Ecological Restoration Project (NPS)

• Several Yosemite campground rehabilitation projects, such as at Bridalveil Horse Camp, Yosemite Creek Campground, Tamarack Campground, Wawona Campground, and Hodgdon Meadow Campground (NPS)

• The Merced River Canyon Trail Acquisition (BLM)

These projects would provide increased access for visitors to the park and expand recreational opportunities in the vicinity of the park.

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

• The Yosemite Valley Plan (NPS)

• The Update to the Yosemite Wilderness Management Plan (NPS)

These projects have the potential to enhance the quality of the visitor experience in the wilderness and Yosemite Valley but also could result in the removal of existing recreational facilities. For example, the Yosemite Wilderness Management Plan could prescribe the closure of the High Sierra Camps. The structures would remain to be interpreted as cultural resources. This change could be considered a local, long-term, adverse impact to some users, due to the loss of a unique lodging experience in the wilderness. 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 in the wilderness, a reduction in stock impacts, improvements in scenic and natural quiet, and improvements in opportunities for solitude and a primitive and unconfined recreational experience.

Reasonably foreseeable projects that could have a net adverse effect on visitor experience include:

• Several development-related projects, including Yosemite Motels, El Portal (Mariposa Co.); Silvertip Resort Village Project (Mariposa Co.); Double Eagle Resort, June Lake (Mono Co.); Tioga Inn, Lee Vining (Mono Co.); June Lake Highlands (Mono Co.); Evergreen Lodge Expansion (Tuolumne Co.); Hardin Flat Lodging and Conference Facility (Tuolumne Co.); Motel and Restaurant, Second Garrotte Basin (Tuolumne Co.); the Rio Mesa Area Plan (Madera Co.); Hazel Green Ranch (Mariposa Co.); and the Yosemite West Rezoning Application (NPS)

These projects could increase visitor use in the park and in the river corridor and could contribute to increased congestion and reduce the quality of specific, solitude-based recreational opportunities in the park.

The cumulative projects would have a long-term, negligible, 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 the removal of specific recreational opportunities.

Alternative 1 and the cumulative projects within and in the vicinity of Yosemite National Park would result in a long-term, beneficial impact on recreation, because an increase in visitor access and an expansion of recreational opportunities would only be partially offset by the removal of specific recreational opportunities.

Under Alternative 1, availability and diversity of recreational opportunities in the river corridor would continue as presently managed. Activities such as the use of non-motorized watercraft (e.g., rafts, inner tubes, kayaks), swimming and wading, hiking, backpacking, camping, rock climbing, fishing, sightseeing, photography, nature study, bicycling, and stock use would continue to be available at existing levels. Trails and campgrounds within the corridor would be maintained in their current locations. The river environment would continue to degrade, and this continuing degradation would have a long-term, adverse effect on recreational activities.

Alternative 1 and the cumulative projects within and in the vicinity of Yosemite National Park would result in a long-term, beneficial impact on recreation, because an increase in visitor access and an expansion of recreational opportunities would only be partially offset by the removal of specific recreational opportunities.

Interpretation & Orientation

Analysis

General Impacts. The following discussion provides an overview of the types of impacts on interpretation and orientation that could occur within the Merced River corridor from application of Alternative 1.

Impacts in Wilderness. Interpretive programs in the wilderness, such as ranger talks at Little Yosemite Valley Backpackers Campground and ranger-led loop hikes in the wilderness that visit the High Sierra Camps, including Merced Lake High Sierra Camp, would continue as currently managed.

Impacts in Yosemite Valley. Interpretation and orientation services include programs offered at the Yosemite Valley Visitor Center, The Ansel Adams Gallery, Lower Pines Campground amphitheater, ranger-led walks and talks, and other related park partner programs. The diversity and availability of programs would continue under the existing management approach.

The main Valley Visitor Center is difficult to find, and although it is centrally located in Yosemite Village, directional signs in Yosemite Valley are not ideal and there is no adjacent parking. This situation would continue under Alternative 1 and could constitute an adverse impact on visitor experience, as visitors wander around the Valley in search of the Visitor Center. Relocation of this facility is not considered under Alternative 1; however, the proper placement of improved signs and directional information could mitigate this impact.

Some interpretive and educational services and facilities provided by the National Park Service and the park partners (Yosemite Institute, Yosemite Association, Yosemite Fund, Sierra Club, Yosemite Concession Services, and The Ansel Adams Gallery) would continue at present levels and in present locations throughout the park.

Impacts in the Merced River Gorge and El Portal. There are no interpretive programs currently offered in the gorge or in El Portal. Under Alternative 1, this condition would not change.

Impacts in Wawona. Interpretation and orientation services include programs offered at the Pioneer Yosemite History Center, Wawona Campground amphitheater, ranger-led walks and talks, and other related park partner programs. The diversity and availability of programs would continue under the existing management approach.

Summary of Alternative 1 Impacts. The availability and diversity of interpretation and orientation programs and services would not change under Alternative 1. This alternative provides flexibility in terms of where exhibits could be placed, trails built, and programs offered for the benefit of visitors.

Cumulative effects on visitor experience as it relates to orientation and interpretation are based on analysis of past and reasonably foreseeable future actions in the Yosemite region. 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. 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 the jurisdiction of these agencies. 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 non-motorized 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).

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.

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

• The Yosemite Valley Plan (NPS)

• South Entrance/Mariposa Grove Site Planning (NPS)

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

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

• The Update to the Yosemite Wilderness Management Plan (NPS)

This planning effort could prescribe the closure of the Merced Lake High Sierra Camp. The potential discontinuation of visitor use of the Merced Lake High Sierra Camp would disrupt the High Sierra Camp loop-trip experience and the ranger-led interpretive hikes in the wilderness. 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 cumulative 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 loss of ranger-led hikes in the wilderness.

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

The availability and diversity of interpretation and orientation programs and services would not change under Alternative 1. This alternative provides flexibility in terms of where exhibits could be placed, trails built, and programs offered for the benefit of visitors.

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

Visitor Services

Analysis

General Impacts. The following discussion provides an overview of the types of impacts on visitor services that could occur within the Merced River corridor from application of Alternative 1.

Impacts in Wilderness. Under Alternative 1, the availability and diversity of visitor services in the wilderness would not change from what is currently available. Access to an organized camping experience in the wilderness at the backpackers campgrounds (Little Yosemite Valley, Moraine Dome, and Merced Lake Backpackers Campgrounds) and lodging at the Merced Lake High Sierra Camp would not change under this alternative. In addition, visitors could still establish independent camps in the wilderness under the wilderness permit and quota systems and the Wilderness Management Plan. In the wilderness, camping is controlled through the quota system as part of the Wilderness Management Plan, and although the park is able to accommodate visitor demand parkwide, there is unmet demand for wilderness permits in the Merced River corridor.

Impacts in Yosemite Valley. Under Alternative 1, the availability and diversity of visitor services would not change from what is currently available to the visitor in Yosemite Valley. Visitor services include camping (e.g., Camp 4 (Sunnyside Campground), North Pines Campground, Upper and Lower Pines Campgrounds, and the backpackers campground at Tenaya Creek), lodging (e.g., Curry Village, Housekeeping Camp, Yosemite Lodge, and The Ahwahnee), and food and retail services.

At present, visitor demand for camping and lodging in Yosemite Valley is unmet during the summer months. During these peak months, Camp 4 (Sunnyside Campground), North Pines Campground, Upper Pines Campground, and Lower Pines Campground are generally full.

In addition, Housekeeping Camp, Curry Village, and Yosemite Lodge (which is at capacity year-round) are typically full in the peak months. The park's inability to meet camping and lodging demand in Yosemite Valley was exacerbated by the damage sustained during the 1997 flood. Campsites that were closed as a result (e.g., Upper River and Lower River Campgrounds) would not necessarily be reopened under this alternative. Some units at Yosemite Lodge were also removed due to damage and would not be replaced.

No further direction beyond existing park plans would be provided regarding rebuilding, relocating, or removing camping and lodging facilities, with an unknown impact on the number of campsites or lodging units within the park. Thus, the number of campsites and lodging units in the corridor could increase, decrease, or stay the same under Alternative 1.

It is possible that Alternative 1 could perpetuate the inability to meet demand for camping and lodging, or it could alleviate some of the current unmet demand. It is possible that some segment of the visitor population might, as a result, choose to visit the park during other times of the year. Some visitors would be forced to plan further ahead to secure camping and lodging accommodations during peak times, if there were to be no change or a decrease in numbers of campsites and lodging units. The inability to meet camping and lodging demand could constitute an adverse impact, because some visitors likely would be displaced as a result of an insufficient number of campsites and lodging units in the park.

The National Park Service, park partners, and the primary park concessioner would continue to operate food service and retail outlets in Yosemite Valley, and thus could continue to meet demand. As a result, Alternative 1 would have no impacts associated with these aspects of visitor services.

Impacts in the Merced River Gorge and El Portal. Visitor services currently offered in the gorge include picnicking, lodging, and restaurants run by private businesses, and a store and gas station operated as park concessions. These services would not be affected by Alternative 1.

Impacts in Wawona. During peak summer months, Wawona Campground and the Wawona Hotel are typically full. Under Alternative 1, this condition would not change, which would further exacerbate the park's ability to meet demand for camping and lodging, especially during peak summer months. The existing concession-operated food and retail services in Wawona would continue to operate at present levels.

Summary of Alternative 1 Impacts. Alternative 1 could perpetuate the inability to meet demand for camping and lodging. This is considered a potential long-term, adverse impact on the availability and diversity of visitor services.

Cumulative effects on visitor experience as it relates to visitor services are discussed herein and are based on analysis of past 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 experience within the river corridor or in the park vicinity.

Past Actions. Upper and Lower River Campgrounds and part of Lower Pines Campground were closed following damage sustained during the 1997 flood. This resulted in a decrease in the overall number of campsites available to visitors in the Valley. Similarly, lodging units at the Yosemite Lodge were removed as a result of flood damage and have not been replaced.

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.

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

• The Yosemite Area Regional Transportation System (YARTS)

• Several Yosemite campground rehabilitation projects, such as at Bridalveil Horse Camp, Yosemite Creek Campground, Tamarack Campground, Wawona Campground, and Hodgdon Meadow Campground (NPS)

• Several development-related projects, including Yosemite Motels, El Portal (Mariposa Co.); Silvertip Resort Village Project (Mariposa Co.); Double Eagle Resort, June Lake (Mono Co.); Tioga Inn, Lee Vining (Mono Co.); June Lake Highlands (Mono Co.); Evergreen Lodge Expansion (Tuolumne Co.); Hardin Flat Lodging and Conference Facility (Tuolumne Co.); Motel and Garrotte Restaurant, Second Garrotte Basin (Tuolumne Co.); the Rio Mesa Area Plan (Madera Co.); and the Yosemite West Rezoning Application (NPS).

These projects could improve transportation to and from the park, which would ultimately have a beneficial effect on visitor services by providing increased access for visitors staying outside the park. In addition, the number of campsites and lodging units in the park and in the park vicinity could increase, which would improve visitor services for park visitors.

Reasonably foreseeable projects that could have a net adverse effect on visitor services include:

• The Update to the Yosemite Wilderness Management Plan (NPS)

The Yosemite Wilderness Management Plan could prescribe the closure of the High Sierra Camps. This change could affect the ability to meet the lodging demand in the corridor and park and could be considered an adverse impact due to the loss of a unique lodging experience in the wilderness.

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

• The Yosemite Valley Plan (NPS)

The Yosemite Valley 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. Visitor services could be improved by reducing automobile congestion, limiting crowding, and expanding orientation and interpretation services. The Yosemite Valley Plan, however, would prescribe a reduction in camping and lodging units in Yosemite Valley, which would have an adverse effect on the provision of visitor services.

These cumulative projects would have a long-term, minor, adverse impact on visitor services due to the reduction of camping and lodging opportunities in Yosemite Valley and potential closure of the High Sierra Camps. These adverse impacts would be partially offset by improving transportation to and from the park, 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, adverse impact on visitor services because of the potential reduction of camping and lodging opportunities in Yosemite Valley and the potential removal of the High Sierra Camps. This adverse impact would be partially offset by improving transportation to and from the park, rehabilitating and expanding some campgrounds in the park, and expanding lodging opportunities outside the park.

Alternative 1 could perpetuate the inability to meet demand for camping and lodging. This is considered to be a potential long-term, adverse impact on the availability and diversity of visitor services.

Alternative 1 and the cumulative projects within and in the vicinity of Yosemite National Park would result in a long-term, adverse impact on visitor services because of the potential reduction of camping and lodging opportunities in Yosemite Valley and the potential removal of the High Sierra Camps. This adverse impact would be partially offset by improving transportation to and from the park, rehabilitating and expanding some campgrounds in the park, and expanding lodging opportunities outside the park.

Wilderness Experience

Analysis

General Impacts. The following discussion provides an overview of the types of impacts on wilderness experience that could occur within the Merced River corridor from application of Alternative 1.

Under Alternative 1, access to Yosemite wilderness within the corridor would continue as currently managed under the wilderness permit system and Wilderness Management Plan. Additionally, group and primitive camping experiences, hiking opportunities, and opportunities for solitude in the wilderness would remain unchanged. At present, the park is able to accommodate visitor requests for wilderness permits parkwide; however, demand for permits specifically in the Merced River corridor typically exceed demand as controlled by the quota system. The quota system helps to maintain the management direction that visitors have the ability to experience solitude and engage in a primitive camping experience in the wilderness. This inability to meet demand for wilderness permits in the Merced River corridor would likely continue under Alternative 1.

Summary of Alternative 1 Impacts. Alternative 1 would continue the current management practices for the wilderness area. Since the inability to meet demand for wilderness permits would continue, this is a long-term, adverse impact.

Cumulative effects on the wilderness experience 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 the wilderness experience within the river corridor or in the park vicinity.

Past Actions. The wilderness permit/trailhead quota system, established in 1974-76 set limits for the numbers of people allowed to enter the wilderness per day per trailhead. These limits were based on extensive research and monitoring to assess capacity based on ecological and social considerations, and were in response to exceptionally high levels of use in the early to mid-1970s. This system has had beneficial impacts on the wilderness experience through implementation of a quota system to protect natural resources.

Present Actions. The wilderness permit/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.

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

• Several planning or restoration efforts are in various stages of development, including the Fire Management Plan (NPS); the Fire Management Action Plan for Wilderness (USFS); the Sierra Nevada Framework for Conservation and Collaboration (USFS); Management Direction for the John Muir, Ansel Adams and Dinkey Lakes, and Monarch Wildernesses (USFS); the Pinecrest Basin Forest Plan Amendment (USFS, Stanislaus); the Tuolumne Meadows Development Concept Plan (NPS); and Tuolumne Wild and Scenic River Management Plan (NPS)

• The Merced Canyon River Trail Acquisition (BLM)

These projects could result in the restoration of wilderness areas within the park and in the park vicinity. Any improvement to the wilderness ecosystem is considered to be a long-term, beneficial impact.

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

• The Update to the Yosemite Wilderness Management Plan (NPS)

The Yosemite Wilderness Management Plan could prescribe the closure of the High Sierra Camps. The structures would remain to be interpreted as cultural resources. This change could affect the ability to meet lodging demand and would impact some users due to the loss of a unique lodging experience in the wilderness. In addition, the potential discontinuation of visitor use of the High Sierra Camps would eliminate the High Sierra Camp loop-trip experience. 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 in the wilderness and a reduction in stock impacts. 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 long-term, adverse impact of removing the High Sierra Camps.

Alternative 1 and the cumulative projects within and in the vicinity of Yosemite National Park would result in a long-term, beneficial impact to the wilderness experience, because the beneficial improvements to the wilderness ecosystem would offset the adverse removal of the High Sierra Camps.

Alternative 1 would continue the current management practices for the wilderness area. Since the inability to meet demand for wilderness permits would continue, this is a long-term, adverse impact.

Alternative 1 and the cumulative projects within and in the vicinity of Yosemite National Park would result in a long-term, beneficial impact to the wilderness experience, because the beneficial improvements to the wilderness ecosystem would offset the adverse removal of the High Sierra Camps.

Social Resources

Land Use

Analysis

General Impacts. Because the basic land use designation of Yosemite National Park (i.e., public parklands) would not change under Alternative 1, and because National Park Service policy concerning the acquisition of private lands within or adjacent to the park is compatible with current plans and policies, Alternative 1 would have no land use impacts.

Private property within the river corridor in El Portal and Wawona is not zoned under the Merced River Plan. Alternative 1 would not result in conflicts with existing land uses or existing plans and policies and would not induce changes in those land uses.

Section 8 of the Wild and Scenic Rivers Act withdraws lands within the boundaries of Wild and Scenic Rivers from "public entry, sale, or disposition under the public land laws of the United States." This section of the Wild and Scenic Rivers Act preempts public land laws, such as the 1872 General Mining Act, under which nonreserved public lands may be disposed of for private use. However, because Yosemite National Park is by definition "reserved land," no additional lands have been identified for withdrawal under the Merced River Plan. Furthermore, much of the river corridor had previously been withdrawn after the creation of Yosemite National Park and the establishment of the El Portal Administrative Site (72 Stat. 1772).

In accordance with Section 9 of the Wild and Scenic Rivers Act, lands within one-quarter mile of the main stem and South Fork of the Merced River have been withdrawn from all forms of appropriation under mining and mineral leasing laws of the United States. Because much of the river corridor had previously been withdrawn after the creation of Yosemite National Park and the establishment of the El Portal Administrative Site (72 Stat. 1772), no additional lands have been identified for withdrawal under the Merced River Plan.

Summary of Alternative 1 Impacts. Since the basic land use of the park would not change, no impacts to land uses would occur as a result of Alternative 1.

Cumulative impacts to land use discussed herein 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 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 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 non-motorized 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).

Present Actions. The El Portal Road Reconstruction Project (NPS) does not affect the land uses within the Merced River corridor.

Reasonably Foreseeable Future Actions. Reasonably foreseeable future actions proposed in the region that are anticipated to change overall land uses can be separated into local and regional projects. Local projects (i.e., those within the park and involving parklands) being carried out under the direction of the National Park Service include:

• The Yosemite Valley Plan, the Yosemite View parcel land exchange, El Portal; South Entrance/Mariposa Grove Site Planning; Resources Management Building; Yosemite West Rezoning Application; Tuolumne Meadows Development Concept Plan, and Tuolumne Wild and Scenic River Management Plan; Wilderness Boundary Protection Land Exchange, Seventh Day Adventist Camp, Wawona (NPS); and Crane Flat Campus Redevelopment (NPS, YNI)

• Several Yosemite campground rehabilitation projects, such as at Tamarack Campground, Bridalveil Horse Camp, Yosemite Creek Campground, Hodgdon Meadow Campground, and the Wawona Campground Improvement (NPS)

Local projects have the potential to change land uses within the park. For example, the Yosemite Valley Plan could change existing land uses and the intensity of existing land uses within portions of the Merced River corridor in Yosemite Valley as well as in El Portal and Wawona. These changes to land uses would be dictated by the development plans outlined in the Yosemite Valley Plan.

Another example of a local project is the land exchange between the National Park Service and the owner of a parcel of private property near the park's western entrance at the El Portal Administrative Site. The owner of the private parcel would receive a plot of National Park Service land adjacent to the owner's hotel properties in exchange for the landowner's plot two miles west of the Arch Rock Entrance Station. This land exchange would allow the National Park Service to construct facilities, such as a vehicle turnaround area, that would increase the vehicle handling efficiency of the entrance station. The U.S. Congress has passed legislation allowing this land exchange to occur, but it is not yet completed. Though completion of the land exchange would alter the land use for those two plots of land, the overall effect would be insignificant, because the two plots of land are close together and there would be no net change in the amount of each type of land use in the area. A similar land exchange would also take place in Wawona. The Seventh Day Adventist recreational camp is located in Wawona on privately owned land inside the boundaries of Yosemite National Park. The privately owned land occupied by the camp literally abuts portions of Yosemite's designated Wilderness. To protect designated Wilderness, this project would exchange lands between the National Park Service and the Seventh Day Adventist camp.

Regional projects (those that take place outside of the park) that would affect land use and planning within the Yosemite region and are not under National Park Service jurisdiction include:

• Projects undertaken by county governments include: Hazel Green Ranch (Mariposa Co.); Mariposa County General Plan Update (Mariposa Co.); Yosemite Motels, El Portal (Mariposa Co.); Mariposa Creek Pedestrian/Bike Path (Mariposa Co.); Silvertip Resort Village Project (Mariposa Co.); Rio Mesa Area Plan (Madera Co.); University of California, Merced Campus (Merced Co.); Buildout of the City of Merced, General Plan (City of Merced); Double Eagle Resort, June Lake (Mono Co.); Tioga Inn, Lee Vining (Mono Co.); Evergreen Lodge Expansion (Tuolumne Co.); Hardin Flat Lodging and Conference Facility (Tuolumne Co.); Motel and Restaurant, Second Garrotte Basin (Tuolumne Co.); and Evergreen Road Improvements (multi-agency, see Appendix G)

• Projects undertaken by federal agencies include: South Fork and Merced Wild and Scenic River Implementation Plan (USFS, BLM); Sierra Nevada Framework for Conservation and Collaboration (USFS); and Merced River Canyon Trail Acquisition (BLM)

Regional projects have the ability to alter land use in the park vicinity. An example of such a project would be the Mariposa County General Plan Update, which is scheduled to begin in 2000. Although the plan does not explicitly call for land use changes, it does provide general guidance for land use, zoning, and development throughout Mariposa County, which could likely impact land use in the long term.

Another regional project that could affect land use is the South Fork and Merced Wild and Scenic River Implementation Plan. This plan covers management of lands along river segments including: a 15-mile portion of the main stem extending from the El Portal Administrative Site to a point 300 feet upstream of the confluence with Bear Creek; a 21-mile segment of the South Fork from the park boundary to the confluence of the Merced River; and a 3-mile segment of the South Fork just upstream of Wawona, where the National Park Service has jurisdiction over the north side of the river and the U.S. Forest Service has jurisdiction over the south side. The plan calls for the long-term protection of natural and cultural resources, and managing the area for the use and enjoyment of visitors in a way that will leave the resource unimpaired for future use and enjoyment as a natural setting.

The impact intensity of planning projects would depend upon the extent to which the plan's recommendations were implemented. Land uses would most likely shift in various areas. The short-term impacts on land use would be neither adverse nor beneficial; likewise, long-term impacts on land use would be neither adverse nor beneficial.

Alternative 1 and the cumulative projects within and in the vicinity of Yosemite National Park would result in no net effect on land use (i.e., the impact would be neither beneficial nor adverse), due to the fact that land uses would simply shift.

Since the basic land-use designation would not change, no impacts to land uses would occur as a result of Alternative 1.

Alternative 1 and the cumulative projects within and in the vicinity of Yosemite National Park would result in no net effect on land use (i.e., the impact would be neither beneficial nor adverse), due to the fact that land uses would simply shift.

Transportation

Analysis

General Impacts. The following discussion provides an overview of the types of transportation impacts that could occur within the Merced River corridor from application of Alternative 1.

Camping, lodging, parking, and circulation facilities are assumed to remain as they are under existing conditions. Operational improvements (e.g., new signs to more efficiently direct visitors to destinations) could be made under Alternative 1, but no such improvements are assumed for this analysis. Some lodging facilities at Yosemite Lodge that were damaged by the 1997 flood were repaired. Other camping and lodging facilities damaged by, and/or removed after, the 1997 flood, however, would not be repaired or rebuilt under Alternative 1, and such facilities undamaged by the flood would remain. Parking for private automobiles and commercial tour buses would remain dispersed at sites and turnouts throughout the Merced River corridor. Shuttle bus routes would most likely continue to serve only the east Valley. The Restricted Access Plan would continue to be implemented to manage visitor access during periods of high visitation when there were more vehicles than available parking spaces and, in some instances, than roads could accommodate.

Traffic congestion and delays would continue to occur at busy intersections and could worsen somewhat as visitation levels increase in the future. This could trigger the need to implement the Restricted Access Plan on an increasing number of days during the peak season. It is expected that increases in visitation levels would occur primarily during the current nonpeak periods (e.g., during months on either side of peak summer months, and on weekdays during peak summer months). If that were to occur, then traffic congestion during those nonpeak periods could approximate current congestion during peak periods. Increases in visitation during peak periods also could occur, and to the degree that such increases happen, congestion would marginally worsen. Increasing congestion and delays would be a long-term, adverse impact on traffic conditions.

Parking demand likely would exceed parking availability, which could trigger the need to implement the Restricted Access Plan on an increasing number of days during the peak season. Visitors would continue to be able to drive their private vehicles, but many would not be able to find parking spaces near their destinations and would need to park in roadside spaces or spend more time searching for parking. The need to park in roadside spaces could increase conflicts between vehicles, as visitors unable to find an authorized space could decide to park in unauthorized/improper areas. This would have a long-term, adverse impact on traffic safety conditions by slightly increasing the potential for traffic safety hazards.

Summary of Alternative 1 Impacts. Increases in visitation during peak periods could occur, and congestion and delays would be a long-term, adverse impact on traffic conditions. Parking demand likely would exceed parking availability, which could trigger the need to implement the Restricted Access Plan on an increasing number of days during the peak season. Visitors would continue to be able to drive their private vehicles, but many would not be able to find parking spaces near their destinations and would need to park in roadside spaces or spend more time searching for parking. The need to park in roadside spaces could increase conflicts between vehicles, as visitors unable to find an authorized space could decide to park in unauthorized/improper areas. This would have a long-term, adverse impact on traffic safety conditions by slightly increasing the potential for traffic safety hazards.

Cumulative transportation effects discussed herein 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 access and transportation in the vicinity of the river corridor.

Past Actions. Development of a circulation system that includes roadways, parking areas, and bridges has occurred within and in the vicinity of Yosemite National Park. This circulation system was developed to provide access to the park and the surrounding areas. In the 1980s, the Restricted Access Plan was developed for use when traffic and parking conditions in Yosemite Valley are overcongested. The plan has the effect of reducing the number of incoming vehicles until the traffic volume and parking demand in the Valley decreases sufficiently (as departing visitors leave the Valley) to stabilize traffic conditions.

Present Actions. The El Portal Road Reconstruction Project (NPS) is currently underway and has both adverse (short-term during construction) and beneficial (long-term) effects on transportation. Short-term, construction-related effects include visitor delays and safety hazards through the construction work zone. Those effects are mitigated by implementation of a traffic control plan, with measures such as strict construction timing restrictions, roadway safety procedures, flaggers, and signalling. Current safety improvements on Segments A, B, and C of El Portal Road would facilitate regional transit service on that route, which would be a long-term, beneficial impact.

Reasonably Foreseeable Future Actions. Reasonably foreseeable future actions proposed in the region are separated below into four general categories: (1) projects anticipated to have a net beneficial effect; (2) projects anticipated to have both beneficial and adverse effects; (3) projects anticipated to have adverse effects; and (4) projects not anticipated to have a net adverse or beneficial effect.

Reasonably foreseeable projects that could have a cumulative, long-term, beneficial effect on regional transportation include the following:

• The Yosemite Area Regional Transportation System (YARTS)

• San Joaquin Corridor Rail Projects (DOT, Amtrak)

• The Yosemite West Rezoning Application (NPS)

  The Yosemite Valley Plan (NPS)

The aforementioned projects, individually and in combination, would reduce congestion by encouraging travel to the park by alternative (non-private vehicle) modes. For example, YARTS is a collaborative, multi-agency effort to evaluate the feasibility of a regional transportation system and to determine the organizational structure of an entity that would implement and operate the system. The intent of YARTS is to provide an attractive alternative to private vehicles by expanding the range of travel options for visitors to Yosemite Valley and to other primary park destinations, and for employees commuting to work in the park. It also could provide a means for visitors to travel to Yosemite Valley when the Restricted Access Plan is implemented for private vehicles during times of severe congestion. The initial YARTS service would be a demonstration project (scheduled to begin by early summer 2000), with a target market of visitors staying overnight in the gateway communities and employees working at Yosemite National Park who live in the gateway communities. A successful YARTS would reduce the number of day visitors arriving in private vehicles. Similarly, the Yosemite West Rezoning Application would include a provision for a regional staging area to provide visitor parking and linkage to regional public transportation systems. The preferred alternative of the Yosemite Valley Plan would consolidate parking for day visitors at Yosemite Village and in parking areas outside Yosemite Valley (at Badger Pass, El Portal, and South Landing), which would result in a reduction in vehicle travel in the eastern portion of Yosemite Valley. The circulation pattern in Yosemite Valley would be changed by the removal of roads from Ahwahnee and Stoneman Meadows, the removal of parking from Curry Orchard, the conversion of Northside Drive to a multi-use (bicycle and pedestrian) paved trail from El Capitan crossover to Yosemite Lodge, and the conversion of Southside Drive to two-way traffic between El Capitan crossover and Curry Village. The implementation of these projects would result in a reduction in automobile congestion within Yosemite Valley. In addition, parking lots(s) outside the Valley could be used to intercept day visitors and shift those visitors to Valley-bound shuttle buses.

Reasonably foreseeable projects that could have a short-term, adverse effect but a cumulative, long-term, beneficial effect on regional transportation include:

• Highway 41 Extension (Madera Co.)

• South Entrance/Mariposa Grove Site Planning (NPS)

• Yosemite Valley Shuttle Bus Stop Improvements (NPS)

• South Fork Merced River Bridges Replacement (NPS)

  Road Realignment and Bridge Replacement of Highway 49 and Old Highway (Mariposa Co.)

• Mariposa Creek Pedestrian/Bike Path (Mariposa Co.)

• Evergreen Road Improvements (multi-agency, see Appendix G)

Although the above projects would have site-specific and short-term, adverse effects (e.g., construction-related transportation effects), the general goal of each of these projects is to improve regional transportation circulation and safety.

Reasonably foreseeable projects that could have a short-term, adverse effect on regional transportation include:

• Several water improvement projects, such as the Tuolumne Meadows Water and Wastewater Improvements, White Wolf Water System Improvements, Hodgdon Meadow Water and Wastewater Treatment Improvements, and Replacement/Rehabilitation of Yosemite Valley Sewer Line (NPS); Cherry Dam Fuse Gate, O'Shaughnessy Dam Well, and O'Shaughnessy Compound Water System Improvements (City and Co. of San Francisco)

• Forest-related projects, such as the Orange Crush Fuels Treatment Projects and the A-Rock Reforestation (USFS, Stanislaus), and the Rogge. Ackerson Fire Reforestation (Tuolumne Co.)

• Various development-related projects, such as the Yosemite View parcel land exchange, El Portal (NPS); Rio Mesa Area Plan (Madera Co.); Yosemite Motels, El Portal (Mariposa Co.); Silvertip Resort Village Project (Mariposa Co.); University of California, Merced Campus (Merced Co.); Buildout of City of Merced, General Plan; Double Eagle Resort, June Lake (Mono Co.); Tioga Inn, Lee Vining (Mono Co.); June Lake Highlands (Mono Co.); Evergreen Lodge Expansion (Tuolumne Co.); Hardin Flat Lodging and Conference Facility (Tuolumne Co.); Motel and Restaurant, Second Garrotte Basin (Tuolumne Co.); Hazel Green Ranch (Mariposa Co.); Crane Flat Campus Redevelopment (NPS, YNI); Wilderness Boundary Protection Land Exchange, Seventh Day Adventist Camp, Wawona (NPS); and the new Resources Management Building (NPS)

The adverse effects associated with the above projects would be short term in nature, primarily related to construction-generated traffic on roadways serving the project sites. These projects would not result in any net, long-term effects to regional transportation.

Given the potential for a reduction in the number of day visitors arriving in private vehicles, these cumulative projects would have a long-term, minor to moderate, beneficial impact on the regional transportation system. The impact intensity of any planning projects would depend upon the extent that the plan's recommendations are implemented. The short-term, construction-related traffic impacts that would occur from development of site-specific projects would not appreciably alter these long-term, beneficial impacts.

Alternative 1 and the cumulative projects within and in the vicinity of Yosemite National Park would result in a long-term, adverse or beneficial impact on traffic and traffic safety conditions in Yosemite National Park, because the beneficial impacts associated with the cumulative projects would be offset by the adverse impacts associated with Alternative 1, including the potential increase in traffic congestion within Yosemite Valley and the potential increase in traffic safety hazards. Whether the impact is adverse or beneficial depends on the implementation of various projects that would benefit the transportation system.

Increases in visitation during peak periods could occur, and congestion and delays would be a long-term, adverse impact on traffic conditions. Parking demand likely would exceed parking availability, which could trigger the need to implement the Restricted Access Plan on an increasing number of days during the peak season. Visitors would continue to be able to drive their private vehicles, but many would not be able to find parking spaces near their destinations and would need to park in roadside spaces or spend more time searching for parking. The need to park in roadside spaces could increase conflicts between vehicles, as visitors unable to find an authorized space could decide to park in unauthorized/improper areas. This would have a long-term, adverse impact on traffic safety conditions by slightly increasing the potential for traffic safety hazards.

Alternative 1 and the cumulative projects within and in the vicinity of Yosemite National Park would result in a long-term, adverse or beneficial impact on traffic and traffic safety conditions in Yosemite National Park, because the beneficial impacts associated with the cumulative projects would be offset by the adverse impacts associated with Alternative 1, including the potential increase in traffic congestion within Yosemite Valley and the potential increase in traffic safety hazards. Whether the impact is adverse or beneficial depends on the implementation of various projects that would benefit the transportation system.

Scenic Resources

Analysis

Impacts in the Wilderness. Scenic resources and views from the Merced River and its banks within the wilderness reaches are generally pristine, except where human use is relatively intense (e.g., in the vicinity of the Little Yosemite Valley Backpackers Campground, Moraine Dome Backpackers Campground, and Merced Lake High Sierra Camp and Backpackers Campground). Under Alternative 1, use of these facilities would continue consistent with existing conditions, and scenic resources at these locations could remain somewhat impaired.

Scenic Outstandingly Remarkable Values of the wilderness reaches of the Merced River include views of the glaciated Merced Lake and Washburn Lake river canyon, Bunnell Cascades, the confluence of tributaries, and the Clark and Cathedral Ranges. Because of the relatively remote location, continuation of current management direction under Alternative 1 is not anticipated to affect these resources.

Impacts in Yosemite Valley. Under Alternative 1, the Merced River could continue to widen in certain areas as a result of human-caused erosion, loss of bank vegetation, and trampling. For this reason, and because Alternative 1 would not address the effect of crowding on enjoyment of scenic resources, the alternative could have an adverse effect on the physical landscape features that determine the character of a given scenic view or sequence of views. It also could affect the ability of visitors to enjoy certain scenic views, including many of the highly valued scenic resources in Yosemite Valley identified in the 1980 General Management Plan. This effect would be directly related to the number of people traveling in the Merced River corridor, the duration of their stay, the density of people gathered at specific views, and the extent and effectiveness of minor restoration programs that could occur under the No Action Alternative. These factors affect both the amount of physical damage caused by humans on the features that define important scenic resources in the park, and the ability of people to experience scenic resources in relative solitude.

Existing facilities and visitor use patterns could continue to affect natural vegetation and soil patterns, reducing vegetative cover and altering natural vegetative patterns. An example includes increased encroachment of conifers within meadow and riparian communities that could, over time, alter the character of a given scenic view or sequence of views or obscure the scenic view altogether.

Overall, park visitation could increase over existing levels, although the increase in park visitation by 2020 is not quantifiable. Though applicable throughout the park, human-caused erosion and crowding is likely to be much more of an issue in Yosemite Valley than in the wilderness, El Portal, or Wawona due to the Valley's much higher concentration of visitors. Efforts to manage visitation and protect scenic resources in high-use areas, such as Yosemite Valley, under the No Action Alternative would be conducted in a piecemeal fashion. In the absence of a comprehensive planning effort to manage increased visitation and maintain and restore natural communities, Alternative 1 would result in a local, long-term, adverse impact on scenic resources, including some of those scenic resources identified in the 1996 Draft Yosemite Valley Housing Plan as Outstanding Remarkable Values in Yosemite Valley.

Impacts in the Merced River Gorge and El Portal. Scenic resources and views from the Merced River and its banks within the Merced River gorge are generally intact, except where facilities intrude upon the natural character. Under Alternative 1, use of these facilities would continue consistent with existing conditions, although the numbers of park visitors accessing these facilities could increase over current levels. In the absence of comprehensive planning efforts to manage increased visitation and maintain and restore natural communities, scenic resources at these locations could be negatively affected by increased visitor use. Increased visitor use and its resultant effects on scenic resources (e.g., degradation of resources, trampling, crowding) could have local, long-term, adverse effects on scenic resources at these locations. Scenic Outstandingly Remarkable Values of the Merced River gorge include views of cascades and waterfalls, the Rostrum, Elephant Rock, and the V-shaped river gorge. Because they are not easily accessible, continuation of current management direction under Alternative 1 is not anticipated to affect these resources.

The El Portal Administrative Site was established by Congress in 1958 to allow relocation of operations and maintenance utilities, facilities, and services out of Yosemite National Park. Since El Portal is an administrative site with substantial existing development, scenic Outstandingly Remarkable Values are not attributed to the El Portal Administrative Site. While there are scenic resources in El Portal, these scenic resources are not exemplary on a regional or national scale.

Impacts in the South Fork. Scenic resources and views from the Merced River and its banks along the South Fork are generally pristine. Since park visitation could increase over existing levels, Wawona would experience a higher concentration of visitors in 2020. Efforts to manage visitation and protect scenic resources in Wawona under the No Action Alternative would be conducted in a piecemeal fashion. In the absence of a comprehensive planning effort to manage increased visitation and maintain and restore natural communities, Alternative 1 would result in a local, long-term, adverse impact on scenic resources in accessible areas of Wawona, including those scenic resources identified in the 1996 Yosemite Valley Draft Housing Plan, such as historic vistas, and views of the confluence and cascades of Chilnualna Creek. Trampling, crowding, and degradation of resources could adversely affect the scenic resources in these areas. Other segments of the South Fork, such as the wilderness and the length of the river below Wawona within the park, are not easily accessible to visitors. Continuation of current management direction under Alternative 1 is not anticipated to affect the scenic resources in these areas. Scenic Outstandingly Remarkable Values of the Wilderness segment and the length of the river below Wawona within the park include views of the Triple Divide Peak, the Sierra Crest, and continual white-water cascades in the deep and narrow canyon of the South Fork.

Summary of Alternative 1 Impacts. In the absence of a comprehensive planning effort to manage increased visitation and maintain and restore natural communities, Alternative 1 would have a local, long-term, adverse impact on scenic resources in developed and easily accessible areas.

Cumulative impacts to scenic resources discussed herein are based on analysis of past 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 scenic resources within the river corridor or in the immediate park vicinity.

Past Actions. Scenic resources have been affected by numerous past actions since the inception of the park. Primary among these, when considered in relation to the potential effects of the Merced River Plan, is the alteration of natural communities caused by Euro-American settlers who lived in the park. For example, attempts to establish agricultural activities and the development of tourism resulted in the drying out of the Valley by breaching the moraine and controlling 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. This has had a local, long-term, adverse effect on scenic resources, as the conifers now block views of important scenic resources that were viewable before the vegetation patterns were changed.

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 non-motorized 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).

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.

Projects that could have a cumulative beneficial effect on scenic resources include those that could reduce the number of vehicles entering the park and therefore the frequency of intrusion of vehicles into the scenic landscape. Projects that improve the general health of ecosystems viewable from or within the Merced River corridor also would result in a net cumulative, beneficial effect on scenic resources. Examples of these types of projects are:

• The Yosemite Area Regional Transportation System (YARTS)

• Yosemite Valley Shuttle Bus Stop Improvements (NPS)

• Update to the Yosemite Fire Management Plan (NPS)

• The Merced River at Eagle Creek Ecological Restoration Project (NPS)

• South Fork Merced River Bridges Replacement (NPS)

• The Sierra Nevada Framework for Conservation and Collaboration, and the Management Direction for the John Muir, Ansel Adams, Dinkey Lakes, and Monarch Wildernesses (USFS)

The general goal of these projects is to either reduce private vehicle traffic in the park, and especially in Yosemite Valley (which would reduce the frequency of vehicles intruding into important scenic resources viewable within or from the Merced River corridor), or to improve the health of ecosystems that make up parts of important scenic resources, either in the park or on lands adjacent to the park. For example, the update to the Yosemite Wilderness Management Plan could result in the removal of the Merced Lake High Sierra Camp, reducing site-specific erosion and trampling and restoring natural vegetation. These cumulative projects would have a net long-term, beneficial impact on scenic resources.

Reasonably foreseeable projects that could have an adverse effect on scenic resources include:

• Replacement/Rehabilitation of Yosemite Valley Sewer Line (NPS)

• Yosemite View parcel land exchange, El Portal (NPS)

The local, long-term, adverse effects of these reasonably foreseeable projects would be related to the potential introduction of new structures and/or infrastructure that would intrude into views of important scenic resources within or viewable from the Merced River corridor. For example, the Yosemite View parcel land exchange could result in new development in an area of El Portal that is currently undeveloped and a reduce the vegetative screening of the existing motel complex. This project would result in increased views of developed structures on the banks of the Merced River from Highway 140.

Reasonably foreseeable projects that could have a mixed effect on scenic resources include:

• The Yosemite Valley Plan (NPS)

• Wawona Campground Improvement (NPS)

The Yosemite Valley Plan would have a local, long-term, beneficial impact on scenic resources in the Valley due to restoration of disturbed or developed land to natural conditions and, in particular, large-scale restoration of areas within the A. scenic category (areas considered to have the most significant scenic views within the Valley). The Yosemite Valley Plan also would include areas of new development in the Valley (largely consolidated in the east Valley), Wawona, and El Portal, resulting in adverse impacts due to visual intrusions in the scenic landscape. However, impacts in these areas contribute directly to the improvement of the scenery within the Valley by removing facilities and restoring impacted areas.

The Wawona Campground Improvement project would have a local, long-term, beneficial impact on scenic resources due to restoration activities to improve the existing degraded campground, including activities to revegetate the riverbanks. Some aspects of the campground improvement project could have adverse effects on scenic resources due to new development in undeveloped areas, such as the proposal to construct an additional campground in Section 35.

These past and reasonably foreseeable future actions could have a net local, long-term, major, beneficial cumulative effect on scenic resources in Yosemite Valley because of the overall emphasis on restoring disturbed or developed land to natural conditions, improving the health of ecosystems, and reducing the number of vehicles. Scenic resources in the Wilderness segments would experience local, long-term, negligible, beneficial cumulative impacts due to the reduction of site-specific erosion and trampling and restoration of natural vegetation. In some developed areas in Wawona and El Portal, the cumulative projects would result in local, long-term, minor, adverse cumulative impacts to scenic resources due to visual intrusions in the scenic landscape from new facilities, such as facilities being relocated from Yosemite Valley.

Alternative 1 and the cumulative projects within and in the vicinity of Yosemite National Park would result in local, long-term, beneficial impacts on scenic resources in designated Wilderness and Yosemite Valley because of the overall emphasis on restoring disturbed or developed land to natural conditions, improving the health of ecosystems within or adjacent to the park, and reducing the number of vehicles traveling through the park. The adverse impacts to scenic resources in the Valley associated with Alternative 1 would be offset by restoration activities planned in the Yosemite Valley Plan. In some developed areas in Wawona and El Portal, Alternative 1 and the cumulative projects would result in local, long-term, adverse impacts to scenic resources due to visual intrusions in the scenic landscape from new facilities, such as facilities being relocated from Yosemite Valley, as prescribed in the Yosemite Valley Plan.

In the absence of a comprehensive planning effort to manage increased visitation and maintain and restore natural communities, Alternative 1 would have a local, long-term, adverse impact on scenic resources in developed and easily accessible areas.

Alternative 1 and the cumulative projects within and in the vicinity of Yosemite National Park would result in local, long-term, beneficial impacts on scenic resources in designated Wilderness and Yosemite Valley because of the overall emphasis on restoring disturbed or developed land to natural conditions, improving the health of ecosystems within or adjacent to the park, and reducing the number of vehicles traveling through the park. The adverse impacts to scenic resources in the Valley associated with Alternative 1 would be offset by restoration activities planned in the Yosemite Valley Plan. In some developed areas in Wawona and El Portal, Alternative 1 and the cumulative projects would result in local, long-term, adverse impacts to scenic resources due to visual intrusions in the scenic landscape from new facilities, such as facilities being relocated from Yosemite Valley, as prescribed in the Yosemite Valley Plan.

Socioeconomics

Social Environment

Analysis

General Impacts. Under Alternative 1, employee housing and commutes would not substantially change from existing conditions in Yosemite Valley, El Portal, and Wawona. The often cramped, crowded, and communal housing conditions for seasonal employees and lack of sufficient housing types for employees with families could continue in Yosemite Valley and Wawona.

Although Yosemite National Park and the El Portal area provide outstanding outdoor recreational opportunities, local communities lack recreation facilities for area residents. For example, Yosemite Valley does not have a community center or other such facility to provide a centralized meeting area for Valley residents. El Portal lacks pedestrian access between Rancheria Flat housing, the Trailer Village, the El Portal Village Center, and local schools. El Portal Road, Foresta Road, and Highway 140 provide the only travel corridors in El Portal, neither of which provides sidewalks or sufficient road berms for safe pedestrian travel. El Portal and Wawona also have limited community amenities. Under Alternative 1, the lack of sufficient community recreational facilities would continue, and the crowded and communal housing conditions could worsen. The above-described conditions would constitute a local, long-term adverse environmental impact associated with the No Action Alternative on the social environments of the Valley, El Portal, and Wawona.

Cumulative Impacts. Cumulative effects on the social environment discussed herein are based on analysis of reasonably foreseeable future actions in the Yosemite region in combination with potential effects of this alternative. The cumulative projects that follow are those most relevant to this environmental discipline.

Reasonably foreseeable future projects that could have a cumulative, beneficial effect on the social environment include:

• Yosemite Area Regional Transportation System (YARTS)

• Merced River Canyon Trail Acquisition (BLM)

Implementation of YARTS would provide additional transportation options for employees and community residents. YARTS could somewhat improve the commuting conditions of employees by providing regional transportation alternatives for those employees resulting in a regional, long-term, beneficial impact on employee commutes.

The Bureau of Land Management's Merced River Canyon Trail Acquisition would allow for the development of a recreational trail west of the El Portal Administrative Site. This project would somewhat improve community amenities in El Portal, resulting in a local, long-term, beneficial impact on the social environment of El Portal.

A reasonably foreseeable future project that could have an adverse effect on the social environment includes:

• The Yosemite View parcel land exchange, El Portal (NPS)

The Yosemite View parcel land exchange would somewhat reduce the amount of open space available to the community of El Portal, although the proposed motel development would incorporate a public trail system and limited nature/river interpretive areas. This project would result in a local, long-term, adverse impact to the social environment of El Portal. This would result from the strain on limited community amenities in El Portal, loss of open space, and the opportunity cost of removing the National Park Service Parkline land from consideration for other community needs.

A reasonably foreseeable future project that could have a mixed effect on the social environment includes:

• The Yosemite Valley Plan (NPS)

The Yosemite Valley Plan would remove substantial amounts of employee housing from Yosemite Valley, and would construct new employee housing in El Portal and Wawona, among other locations. Redesigned housing in Yosemite Valley and new housing in El Portal and Wawona would substantially improve the quality of housing in these communities. 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 experience local, long-term, adverse effects associated with increases in commuting time, change of housing locale, and a decrease in social amenities near housing sites. For the Yosemite Valley workforce, the adverse effects may be so severe that they would no longer be willing to work in the Valley and may leave the area. The social environment in El Portal and Wawona would experience local, long-term, adverse effects due to substantial increases in housing in these communities, although it is expected that the projected population growth would be gradual. Even though the Yosemite Valley Plan calls for the placement of community amenities in El Portal, there could be substantial strains on the limited community amenities of El Portal as employees transition from Yosemite Valley.

The cumulative projects would have a regional, long-term, negligible, beneficial impact on employee commuting conditions due to the provision of regional transportation alternatives. The cumulative projects would have a local, long-term, moderate to major, adverse effect on the social environments of Yosemite Valley, El Portal, and Wawona due to decreases in housing and social amenities near housing and increases in commuting time in Yosemite Valley, and substantial increases in housing in El Portal and Wawona (resulting in substantial strains on the limited community amenities of El Portal and Wawona, even though the Yosemite Valley Plan calls for the placement of community amenities in El Portal). The impact intensity of any planning projects would depend upon the extent that the plan's recommendations are implemented.

Alternative 1 and the cumulative projects within and in the vicinity of Yosemite National Park would result in a regional, long-term, beneficial impact by providing additional transportation options for employees and community residents. Alternative 1 and the cumulative projects would have a local, long-term, adverse effect on the social environments of Yosemite Valley, El Portal, and Wawona due to decreases in housing and social amenities near housing and increases in commuting time in Yosemite Valley, and substantial increases in housing in El Portal and Wawona (resulting in substantial strains on the limited community amenities of El Portal and Wawona, even though the Yosemite Valley Plan calls for the placement of community amenities in El Portal).

Conclusions. Under Alternative 1, the lack of sufficient community recreational facilities would continue, and the crowded and communal housing conditions could worsen resulting in a local, long-term adverse environmental impact on the social environments of Yosemite Valley, El Portal, and Wawona.

Alternative 1 and the cumulative projects within and in the vicinity of Yosemite National Park would result in a regional, long-term, beneficial impact by providing additional transportation options for employees and community residents. Alternative 1 and the cumulative projects would have a local, long-term, adverse effect on the social environments of Yosemite Valley, El Portal, and Wawona due to decreases in housing and social amenities near housing and increases in commuting time to Yosemite Valley, and substantial increases in housing in El Portal and Wawona (resulting in substantial strains on the limited community amenities of El Portal and Wawona, even though the Yosemite Valley Plan calls for the placement of community amenities in El Portal).

Visitor Populations

Analysis

General Impacts. Under Alternative 1, there would be no changes to visitor accommodations in the park. The number of lodging and camping facilities would be maintained at current levels. Camping and lodging facilities damaged by and/or removed after the 1997 flood would not be repaired or rebuilt.

Overall, park visitation would increase over existing levels, although the increase in park visitation by 2020 is not quantifiable. It is expected that increases in visitation would occur primarily during the current nonpeak periods (e.g., during months on either side of peak summer months. known as the shoulder season. and on weekdays during peak summer months).

Increased visitation would likely be day users (local overnighters and day visitors) rather than park overnighters, because in-park accommodations would remain at current levels and are generally filled to capacity during the peak season, and because all-weather lodging facilities operate near capacity year-round. Increases in day use would be limited by the continued implementation of the Restricted Access Plan, as discussed in the transportation section. Since the number of in-park accommodations would not increase or decrease under Alternative 1, there would be no impact on park overnighters associated with increased or decreased opportunities to lodge or camp in the park.

In addition, it is expected that there would be no change in Yosemite visitor spending behavior. No changes are proposed that would alter the types of goods and services available to park visitors. Furthermore, Alternative 1 would not involve any actions that would change the profile of the "typical" Yosemite visitor, such as excluding or attracting different visitor groups. Visitor spending behavior, as described in the 1998 YARTS survey, would be expected to be representative of future Yosemite visitor spending behavior.

Under this alternative, Yosemite visitor spending would increase proportionately to the increase in visitation by 2020. Impacts to the economy associated with changes in visitor spending are discussed below under the heading "Regional Economy."

Cumulative Impacts. Cumulative socioeconomic impacts discussed herein are based on analysis of past and reasonably foreseeable future actions in the Yosemite region in combination with potential effects of this alternative. The cumulative projects that follow are those most relevant to the visitor populations.

Reasonably foreseeable future projects that could have a cumulative, beneficial effect on the visitor population include:

• Yosemite Area Regional Transportation System (YARTS)

• Wawona Campground Improvement (NPS)

YARTS would provide increased access for day visitors to the park and a means for visitors to travel to the Valley if the Restricted Access Plan were implemented. It is anticipated that the regional, long-term, beneficial effect of YARTS would be dependent on the number of visitors that would use the voluntary regional transit system.

The Wawona Campground Improvement project would improve the existing camping facilities at Wawona Campground and would construct additional campground facilities in Section 35 in Wawona. This project would have a local, long-term, beneficial impact on the visitor population by increasing the number of campsites in the park.

A reasonably foreseeable future project that could have a net adverse effect on the visitor population includes:

• The Yosemite Valley Plan (NPS)

The Yosemite Valley Plan would substantially reduce the number of lodging facilities and nominally reduce the number of campsites in Yosemite Valley, resulting in a local, long-term, adverse impact on the visitor population due to decreased opportunities to lodge and camp in the Valley. Since the number of less expensive lodging and camping units would be reduced under the Yosemite Valley Plan, the number of low-income visitors able to stay overnight in the Valley may be reduced. This could represent a local, long-term, adverse impact on the low-income visitor population.

The cumulative projects would have a regional, long-term, negligible to minor, beneficial impact on the visitor population by providing increased access for day visitors to the park. The intensity of the regional impact would be dependent on the number of visitors that would use the voluntary regional transit system. Given the reduction in the number of lodging and camping units, these cumulative projects would have a local, long-term, moderate, adverse impact on the visitor population due to decreased opportunities to lodge and camp in the Valley.

Alternative 1 and the cumulative projects within and in the vicinity of Yosemite National Park would result in a regional, long-term, beneficial impact on the visitor population by providing increased access for day visitors to the park. The intensity of the regional impact would be dependent on the number of visitors that would use the voluntary regional transit system. Alternative 1 and the cumulative projects would have a local, long-term, adverse impact on the visitor population due to the potential overall reduction in the number of lodging and camping units in the park.

Conclusions. Annual park visitation would increase over existing levels (primarily day users), and visitor spending would increase proportionately to the increase in visitation. There would be no impact on park overnighters, since the number of in-park accommodations would not change under Alternative 1.

Alternative 1 and the cumulative projects within and in the vicinity of Yosemite National Park would result in a regional, long-term, beneficial impact on the visitor population by providing increased access for day visitors to the park. The intensity of the regional impact would be dependent on the number of visitors that would use the voluntary regional transit system. Alternative 1 and the cumulative projects would have a local, long-term, adverse impact on the visitor population due to the potential overall reduction in the number of lodging and camping units in the park.

Regional Economy

Analysis

General Impacts. As stated above under the heading "Visitor Populations," the increase in park visitation would likely be day visitors, due to limitations on park accommodations. Demand for lodging during the shoulder season would more likely be accommodated by the gateway communities, which have more capacity during the peak midweek and shoulder season than does the park. In the short term, the increased demand for overnight accommodations may not be accommodated in the region, resulting in some visitors being displaced to or replaced by day visitors. In the long term, it is expected that the lodging market in the gateway areas would respond to visitor demand and sufficient lodging would become available.

The increase in park visitation (primarily during the current nonpeak periods) and proportionate increase in visitor spending would have a long-term, beneficial effect on the regional economy. The peak visitation season would be extended into the shoulder season, somewhat reducing the "seasonality" of the visitor-serving businesses in the affected region by providing a longer revenue-generating period, and additional income and employment for the region. Although the magnitude of the increase in visitation and visitor spending is not known, the effect on the regional economy would not be substantial due to the relatively modest increase in visitor spending in the region (given the continued implementation of the Restricted Access Plan) as compared to the size of the regional tourist economies.

Cumulative Impacts. Cumulative socioeconomic impacts discussed herein are based on analysis of reasonably foreseeable future actions in the Yosemite region in combination with potential effects of this alternative. The cumulative projects that follow are those most relevant to the regional economy.

• The Yosemite Valley Plan (NPS)

• Yosemite Area Regional Transportation System (YARTS)

• Development-related projects, such as Yosemite West Rezoning Application (NPS), Hazel Green Ranch (Mariposa Co.), Yosemite Motels, El Portal (Mariposa Co.), Double Eagle Resort, June Lake (Mono Co.), Tioga Inn, Lee Vining (Mono Co.), Evergreen Lodge Expansion (Tuolumne Co.), Hardin Flat Lodging and Conference Facilities (Tuolumne Co.), Motel and Restaurant, Second Garrotte Basin (Tuolumne Co.), Silvertip Resort Village Project (Mariposa Co.)

The Yosemite Valley Plan would have a short-term, beneficial impact on the regional economy resulting from project construction spending and employment associated with implementation of the alternative. In the long-term, although the Yosemite Valley Plan would result in a decrease in in-park accommodations (and its associated visitor spending), the overall economic impacts of changes from visitor spending and operations spending to the regional economy would be long-term and beneficial. It is anticipated that Yosemite visitor spending associated adverse impacts to the regional economy would be more than offset by increased regional output and employment from expanded National Park Service in-park operations and the proposed new park visitor transit system.

YARTS would provide increased access for day visitors to the park and a means for visitors to travel to the Valley if the Restricted Access Plan were implemented. It is anticipated that the long-term, beneficial effect of YARTS would be dependent on the number of visitors that would use the voluntary regional transit system.

Several new lodging facilities are planned in the affected region, including tent cabins and hard-sided cabins at Hazel Green Ranch outside the park near the Big Oak Flat Entrance Station (Mariposa Co.), a hotel complex as part of the Yosemite West Rezoning Application (NPS), Yosemite Motels, El Portal (Mariposa Co.), Double Eagle Resort in June Lake, Tioga Inn, Lee Vining (Mono Co.), Evergreen Lodge expansion near Camp Mather, a hotel in Hardin Flat, a motel and restaurant in Second Garrotte Basin (Tuolumne Co.), and the Silver Tip Resort Village Project in Fish Camp. Development of these facilities would expand the overnight lodging capacity of the gateway region. By providing local construction spending and employment during development, increasing lodging revenues and transient occupancy taxes, and providing sources of income and employment for area residents, these facilities would have a long-term, beneficial effect on the regional economy. The development of these facilities would increase demand for government services, including police, fire, and other services; it would be expected, however, that local government taxes assessed for these facilities would offset the incremental costs associated with providing such services.

These cumulative projects would have a short-term, minor, beneficial effect on the regional economy due to project construction spending and employment associated with implementation of the projects. The cumulative projects would have a long-term, minor, beneficial effect on the regional economy due to increased regional output and employment from expanded National Park Service in-park operations, increased access for day visitors to the park, and increased lodging revenues and transient occupancy taxes and providing sources of income and employment for area residents.

Alternative 1 and the cumulative projects within and in the vicinity of Yosemite National Park would result in a short-term, beneficial impact on the regional economy due to project construction spending and employment associated with development of the cumulative projects. Alternative 1 and the cumulative projects would result in a long-term, beneficial impact on the regional economy due to an increase in park visitation (primarily during the current non-peak periods), increased regional output and employment from expanded National Park Service in-park operations, increased access for day visitors to the park, and increasing lodging revenues and transient occupancy taxes and providing sources of income and employment for area residents.

Conclusions. The increase in park visitation (primarily during the current nonpeak periods) and proportionate increase in visitor spending would have a long-term, beneficial effect on the regional economy.

Alternative 1 and the cumulative projects within and in the vicinity of Yosemite National Park would result in a short-term, beneficial impact on the regional economy due to project construction spending and employment associated with development of the cumulative projects. Alternative 1 and the cumulative projects would result in a long-term, beneficial impact on the regional economy due to an increase in park visitation (primarily during the current non-peak periods), increased regional output and employment from expanded National Park Service in-park operations, increased access for day visitors to the park, and increasing lodging revenues and transient occupancy taxes and providing sources of income and employment for area residents.

Concessioner

Analysis

General Impacts. Under Alternative 1, there would be no change to the concession facilities in the park. Concession facilities would be maintained at current levels, and facilities removed after the 1997 flood would not be rebuilt. The peak visitation season would be extended into the shoulder season, somewhat reducing the "seasonality" of concession businesses by providing a longer revenue-generating period.

The increase in park visitation and proportionate increase in visitor spending under Alternative 1 would have a local, long-term, beneficial effect on primary park concessioner revenues. The increase in concession revenues would largely be associated with increases in visitor spending on meals, services, and novelties. Lodging revenue increases would be less prevalent, since concession lodging facilities are currently generally operating close to capacity during the peak and shoulder seasons, and no new concession lodging facilities are proposed under this alternative. This would be a local impact, since the concession operations are generally confined to the park.

Cumulative Impacts. Cumulative socioeconomic impacts discussed herein are based on analysis of reasonably foreseeable future actions in the Yosemite region in combination with potential effects of this alternative. The cumulative projects that follow are those most relevant to concessioner operations.

• The Yosemite Valley Plan (NPS)

• Update to the Yosemite Wilderness Management Plan (NPS)

The Yosemite Valley Plan proposes changes to park facilities that are expected to have a local, long-term, adverse impact on the primary park concessioner. The adverse impact is associated with locating new employee housing outside of the Valley, and a decrease in annual concessioner profits (although the profit loss could be offset and result in the concessioner. s net profit being unaffected).

The update to the Yosemite Wilderness Management Plan (NPS) could restrict visitor use of the Merced Lake High Sierra Camp, resulting in closure of the camp to overnight lodging and a loss of revenues to the concessioner associated with providing overnight lodging services. The cumulative effect of the potential closure of Merced Lake High Sierra Camp would be a local, long-term, adverse impact on primary park concessioner revenues.

The cumulative projects would have a local, long-term, minor, adverse impact on the primary park concessioner associated with locating new employee housing outside of the Valley, a decrease annual concessioner profits (although this could be offset and result in the concessioner's net profit being unaffected), and possible closure of Merced Lake High Sierra Camp.

Alternative 1 and the cumulative projects within and in the vicinity of Yosemite National Park would result in a long-term, adverse impact on the primary park concessioner associated with locating new employee housing outside of the Valley, a decrease in annual concessioner profits (although this could be offset and result in the concessioner's net profit being unaffected), and possible closure of Merced Lake High Sierra Camp. The adverse impact associated with the cumulative projects would be somewhat offset by the beneficial impact associated with reducing the "seasonality" of concession operations and increased visitor spending forecast under Alternative 1.

Conclusions. Alternative 1 would have a local, long-term, beneficial effect on concessioner revenues due to a reduction in the "seasonality" of concession operations and increased visitor spending.

Alternative 1 and the cumulative projects within and in the vicinity of Yosemite National Park would result in a long-term, adverse impact on the primary park concessioner associated with locating new employee housing outside of the Valley, a decrease in annual concessioner profits (although this could be offset and result in the primary park concessioner's net profit being unaffected), and possible closure of Merced Lake High Sierra Camp. The adverse impact associated with the cumulative projects would be somewhat offset by the beneficial impact associated with reducing the "seasonality" of concession operations and increased visitor spending forecast under Alternative 1.

Park Operations and Facilities

Analysis

General Impacts. Park operations would continue at current levels of staffing, housing, management, and logistical maneuvering. Traffic congestion identified in the 1980 General Management Plan would not be addressed, and operational functions identified in that plan as being moved to El Portal would remain within Yosemite Valley. Park operations would continue to be primarily dispersed between Yosemite Valley and El Portal. Yosemite Valley would continue to serve as a base of parkwide operations for some functions, including administrative offices, concessions management, some visitor protection, interpretation operations, and the National Park Service stable. However, Resources Management offices, which were damaged during the 1997 flood, would be relocated to El Portal. The National Park Service Administration (headquarters) Building in Yosemite Village would continue to serve an organizational function in the midst of an interpretive complex. This situation complicates park operations in various ways and would continue over time. Dispersed staff requires additional trips to coordinate meetings, primarily between Yosemite Valley and El Portal, which decreases staff productivity (e.g., travel time to and from work areas) and increases road wear on vehicles.

Park operations staffing levels have declined in recent years and, in many cases, are below levels considered necessary. However, personnel will continue to be assigned to essential park operational responsibilities to the extent possible. If current staffing levels remain the same in future years, this would represent a long-term, adverse impact to future park operations.

The following discussion provides an overview of the types of impacts to park operations and facilities that could occur within each segment of the Merced River corridor from implementation of Alternative 1.

Impacts in Wilderness. The wilderness reaches of the Merced River would continue to be managed based on the Wilderness Act and federal and Yosemite National Park wilderness policies and guidelines. Alternative 1 is not anticipated to alter visitor use patterns or facilities within wilderness reaches of the Merced River (main stem and South Fork). Consequently, Alternative 1 would have no impact on park operations and facilities within wilderness segments of the main stem and South Fork of the Merced River.

Impacts in Yosemite Valley. Camping, lodging, parking, and other facilities are assumed to remain as they are under existing conditions. Operational improvements (e.g.,  hiring additional staff) could be made under Alternative 1, but no such improvements are assumed for this analysis. Some lodging facilities at Yosemite Lodge that were damaged by the 1997 flood were repaired and would remain. Other camping and lodging facilities damaged by, and/or removed after, the 1997 flood, however, would not be repaired or rebuilt. Over the long term, old or failing facilities would increase demand on park operations, especially maintenance personnel. It is anticipated that visitor demand and overall use of the park would increase. Increased visitor use could increase adverse impacts on facilities (e.g., wear on roads and trails) and natural areas (e.g., trampling, soil compaction) and increase demand for maintenance, protection, interpretation, and resource (restoration) services over the long term. Parking demand likely would exceed parking availability, which could trigger the need to implement the Restricted Access Plan on an increasing number of days during the peak season. Visitors would continue to be able to drive their private vehicles, but many would not be able to find parking spaces near their destinations and would need to park in roadside spaces or spend more time searching for parking. Visitors unable to locate legal parking could circle the Valley in search of a place to park, which could increase driver aggravation and lead to increases in vehicle accidents (increasing demand on protection services). Visitors unable to locate a parking space could also decide to park in unauthorized/improper areas, which could degrade natural areas (e.g., directly as a result of parking on natural vegetation, indirectly by the creation of informal trails from unauthorized/improper parking areas to park destinations) and increase demand on protection (enforcement), maintenance, and resource (restoration) services. The effects on park operations and facilities would be directly related to the change in visitation and could result in a long-term, adverse effect.

Parking for private automobiles and commercial tour buses would remain dispersed at sites and turnouts throughout the Merced River corridor. This situation complicates park operations in various ways and would continue over time. Patrol of facilities and visitor use of the facilities and adjacent areas would continue consistent with existing conditions. These operations could be aggravated and become worse over time as visitation increases. Although the Restricted Access Plan could continue to be implemented to manage visitor access during periods of high visitation when there were more vehicles than available parking spaces, implementation of the Restricted Access Plan as visitation increases would create its own demand on park operations, primarily protection personnel. It is expected that increases in visitation levels would occur primarily during the current nonpeak periods (e.g., during months on either side of peak summer months, and on weekdays during peak summer months) and could result in the need for additional year-round staff (e.g., protection, maintenance, interpretation). Overall, the effects on park operations and facilities created by dispersed parking would be directly related to the increase in visitation and could result in a long-term, adverse effect.

Overall, increased visitation to Yosemite Valley would increase demand on protection (enforcement), maintenance, and resource (restoration) services. The effects on park operations and facilities would be directly related to the change in visitation and could result in a long-term, adverse impact.

Impacts in Merced River Gorge and El Portal. Old or failing facilities (e.g., El Portal Road) would continue in their current condition. Over the long term, maintenance of these facilities would likely increase and become more complicated, creating an increased demand on park operations, especially maintenance personnel. Increased maintenance of major facilities could also result in temporary facility closure and increase demand for protection services personnel to direct visitors to other areas (e.g., temporary road closures could increase detours and the need for protection services to enforce detours).

Increased visitation to Yosemite Valley could have adverse effects on park operations and facilities of the gorge and El Portal, if implementation of the Restricted Access Plan resulted in increased visitation to these areas by people displaced out of the Valley. Increased use of the gorge and El Portal could increase demand on maintenance, protection, resource, and interpretation staff. If use of the gorge and El Portal increased, it is reasonable to assume that demand for parking, interpretation, and recreational opportunities would increase proportionally. As the demand for parking increases, use of park facilities as well as unauthorized/improper areas would increase. Increased use of either would increase maintenance and protection activities. Increased parking in unauthorized/improper areas also could decrease visitor safety (e.g., parking at unauthorized locations along El Portal Road could increase vehicle accidents and vehicle-visitor conflicts) and degrade natural areas (e.g., directly as a result of parking on natural vegetation, indirectly by the creation of informal trails from unauthorized/improper parking areas to park destinations). These in turn would increase demand on protection (enforcement), maintenance, and resource (restoration) services. The effects on park operations and facilities would be directly related to the change in visitation within the gorge and El Portal and could result in long-term, adverse effects. These impacts would be concentrated in areas of relatively easy access (e.g., along the El Portal Road, in El Portal, and at Cascades). A majority of the gorge is relatively inaccessible, and visitor use is unlikely to increase. Consequently, there would be no impact on park operations and facilities at these locations.

Impacts in Wawona. Effects on park operations and facilities in Wawona would be similar to those described for the gorge and El Portal. Old or failing facilities (e.g., the South Fork Merced River Bridge in Wawona) would continue in their current condition. Over the long term, maintenance of these facilities would likely increase and become more complicated, creating an increased demand on park operations, especially maintenance personnel. Increased maintenance of facilities, such as the South Fork Merced River Bridge, could also result in temporary facility closure and increase demand for protection services personnel to direct visitors to other areas (e.g., temporary bridge closure could increase detours and the need for protection services to enforce detours).

Increased visitation to Yosemite Valley could have adverse effects on park operations and facilities of Wawona if implementation of the Restricted Access Plan resulted in increased visitation to this area by people displaced out of the Valley. Increased use of Wawona could increase demand on maintenance, protection, resource, and interpretation staff similar to that described for the gorge and El Portal. The effects on park operations and facilities would be directly related to the change in visitation within Wawona and could result in long-term, adverse effects.

Summary Alternative 1 Impacts. Long-term, adverse impacts to park operations and facilities as a result of Alternative 1 would be related to dispersed park operations, staffing levels, old or failing facilities, and increased visitation. Park operations would continue to be dispersed between Yosemite Valley and El Portal. Dispersed staff requires additional trips to coordinate meetings, primarily between Yosemite Valley and El Portal, which decreases staff productivity (e.g., travel time to and from work areas) and increases road wear and demand on all personnel. Staffing levels throughout the park have declined in recent years and, in many cases, are below levels considered necessary. If current staffing levels remain the same in future years, this would represent a long-term, adverse impact to future park operations as staff were unable to meet the demand for park operations services and facilities. Old or failing facilities would continue in their current condition, and over the long term, could require increased maintenance. It is anticipated that visitor demand and overall use of the park would increase. Increased visitor use could increase adverse impacts on facilities (e.g., wear on roads and trails) and natural areas (e.g., trampling, soil compaction) and increase demand for maintenance, protection, interpretation, and resource (restoration) services over the long term. In total, Alternative 1 could have long-term, adverse impacts on park operations and facilities.

Cumulative effects on park operations and facilities discussed herein are based on analysis of past, present, and reasonably foreseeable future actions in the immediate Yosemite region in combination with potential effects of this alternative. The extent to which past, present, or reasonably foreseeable projects could have a cumulative effect, when combined with other actions that could result under present National Park Service management strategies, is determined largely by whether such projects would affect demand for park operations services and facilities. For example, effects of projects that change the number of vehicles traveling through the park could combine with effects of the Merced River Plan to either increase or decrease the need for maintenance activities on roads and bridges. Similarly, projects that affect demand for other park operations services and facilities could also have a cumulative effect. These services include maintenance of utility systems, provision of interpretation programs, visitor protection, and resource management.

Past Actions. Park operations and facilities have been affected by numerous past National Park Service management decisions made since the inception of the park. Primary among those, when considered in relation to the potential effects of the Merced River Plan, include relocating the National Park Service maintenance shops and warehouse to El Portal (mostly adverse), removal of the hydroelectric generating plant (mostly adverse), professionalization of law enforcement staff (mostly adverse), rehabilitation of the water and electric distribution systems (mostly beneficial), improved communication systems (cell phones and radios, mostly beneficial), relocating the National Park Service wastewater treatment facility from Yosemite Valley to El Portal (mostly beneficial), and implementation of the prescribed fire program (adverse and beneficial). Overall, there is no net adverse or beneficial effect of these past actions on park operations and facilities.

Present Actions. Present actions that affect park operations and facilities include planning related to the Yosemite Valley Plan (NPS) and the El Portal Road Reconstruction Project (NPS). The Yosemite Valley Plan has substantially increased demand on resource, facility, and planning staff. The El Portal Road Reconstruction Project (NPS) is currently underway and affects park operations and facilities because the reconstruction is placing some increased demand on park operations staff.

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.

Projects that could have a cumulative, beneficial effect on park operations and facilities include those that could reduce the number of visitors entering the park, reduce the number or amount of facilities within the park, or reduce long-term maintenance activities. Examples of these types of projects include:

• Transportation projects including the Yosemite Valley Shuttle Bus Stop Improvements (NPS), The South Fork Merced River Bridges Replacement (NPS), and Evergreen Road Improvements (multi-agency, see Appendix G)

• Several Yosemite utility projects, such as Replacement/Rehabilitation of Yosemite Valley Sewer Line, Tuolumne Meadows Water and Wastewater Improvements, White Wolf Water System Improvements, and Hodgdon Meadows Water and Wastewater Treatment Improvements, and O'Shaughnessy Compound Water System Improvements (NPS)

• Planning efforts, including the South Entrance/Mariposa Grove Site Planning (NPS), update to the Yosemite Fire Management Plan (NPS), update to the Yosemite Wilderness Management Plan (NPS), and Fire Management Action Plan for Wilderness (USFS, Stanislaus)

• Rogge-Ackerson Fire Reforestation (Tuolumne Co.)

Although each of the aforementioned projects could have short-term, adverse effects associated with planning, construction, replacement, or rehabilitation, the general goal of each of these projects is to reduce long-term maintenance. Therefore, these projects could have a long-term, beneficial, cumulative impact on park operations and facilities.

Reasonably foreseeable projects that could have mixed adverse and beneficial effects on park operations and facilities include:

• The Yosemite Area Regional Transportation System (YARTS), which has a goal of increasing transportation options and reducing reliance on automobiles in the area

• Planned rehabilitation of Tamarack Campground, Yosemite Creek Campground, Hodgdon Meadow Campground, Wawona Campground Improvement, and Bridalveil Horse Camp (NPS)

• Development-related projects such as Yosemite West Rezoning Application (Mariposa Co.), Crane Flat Campus Redevelopment (NPS, YNI), Tuolumne Meadows Development Concept Plan (NPS), Resource Management Building, Expansion of Mariposa County Transit System, and University of California, Merced Campus (Merced Co.)

Cumulative effects of the campground rehabilitation projects could be mixed, combining both adverse and beneficial effects. For example, the rehabilitation of Tamarack Campground would have a short-term, adverse effect on park operations and facilities during planning and construction. Post-construction, maintenance would be reduced compared to existing conditions, resulting in a long-term, beneficial impact on park operations and facilities.

Reasonably foreseeable projects that could have an adverse effect on park operations and facilities include:

• The Yosemite Valley Plan (NPS), which would implement the goals of the 1980 General Management Plan

• Tuolumne Meadows Development Concept Plan, and Tuolumne Wild and Scenic River Management Plan (NPS)

• Several regional lodging projects, including Yosemite Motels, El Portal (Mariposa Co.): Silvertip Resort Village Project (Mariposa Co.), Tioga Inn, Lee Vining (Mono Co.); Hazel Green Ranch (Mariposa Co.), and Evergreen Lodge Expansion (multi-agency, see Appendix G)

• Merced River Canyon Trail Acquisition (BLM)

• Sierra Nevada Framework for Conservation and Collaboration (USFS)

Each of these projects would increase demand for services and facilities and add to the cumulative, adverse impact on park operations and facilities. For example, the Yosemite Valley Plan could substantially increase demand on park operations and facilities in the short term during planning, repair, rehabilitation, construction/demolition, and replacement of facilities (e.g., removal of the road through Stoneman Meadow, construction of new campsites, restoration of large areas of Yosemite Valley to natural conditions).

These past, present, and reasonably foreseeable future actions could have adverse, cumulative effects on park operations and facilities because of the increased demand on park operations services and facilities over both the short and long term. The combined effects of Alternative 1 with other cumulative projects would result in a long-term, adverse impact on park operations and facilities because of the increased demand on park operations services and facilities resulting from these projects.

Long-term, adverse impacts to park operations and facilities as a result of Alternative 1 would be related to dispersed park operations, insufficient staffing levels, old or failing facilities, and increased visitation. Park operations would continue to be dispersed between Yosemite Valley and El Portal. Dispersed staff requires additional trips to coordinate meetings, primarily between Yosemite Valley and El Portal, which decreases staff productivity (e.g., travel time to and from work areas) and increases road wear on vehicles and demand on all personnel. Staffing levels throughout the park have declined in recent years and, in many cases, are below those believed necessary by knowledgeable staff. If current staffing levels remain the same in future years, this would represent a long-term, adverse impact to future park operations as staff were unable to meet the demand for park operations services and facilities. Old or failing facilities would continue in their current condition and, over the long term, could require increased maintenance. It is anticipated that visitor demand and overall use of the park would increase. Increased visitor use could increase adverse impacts on facilities (e.g., wear on roads and trails) and natural areas (e.g., trampling, soil compaction) and increase demand for maintenance, protection, interpretation, and resource (restoration) services over the long term. In total, Alternative 1 could have long-term, adverse impacts on park operations and facilities.

The combined effects of Alternative 1 with other cumulative projects would result in a long-term, adverse impact on park operations and facilities because of the increased demand on park operations services and facilities resulting from these projects.

Under Alternative 1, human-made obstructions would continue to obstruct the free-flowing characteristic of the Merced River and subsequently alter stream processes that define channel characteristics such as channel shape and sinuousity and the ability of the river to naturally discharge and dissipate channel-forming flows or flood flows. The streamflow would continue to be permanently altered and would adversely affect the Outstandingly Remarkable Values associated with the free-flowing nature of the river. This impact is expected to worsen over time, resulting in an unavoidable adverse effect.

Alternative 1 would not result in the temporary or permanent loss of any resources.

Since no actions are associated with Alternative 1, no short-term benefits would occur. However, the ongoing impacts to the free-flowing condition of the river, streambank erosion, and impacts to biological communities associated with the river would continue. In addition, obstructions in the river corridor would continue to be present. Therefore, no changes to the free-flowing condition of the river would occur.