This chapter describes the probable consequences (or impacts) that could result under the alternatives described in this East Yosemite Valley Utilities Improvement Plan Environmental Assessment. The chapter is divided into three parts. The Introduction describes the methods and assumptions that are common to all resource topic areas. The Methods and Assumptions section presents the methods used to assess impacts for each specific resource topic. The subsequent sections after Methods and Assumptions describe the impacts anticipated under each alternative, organized by resource topic. Environmental impacts are summarized in table II-2: Summary of Environmental Consequences, provided in Chapter II.

Impact Analysis

Each alternative contains an impact analysis for each individual resource topic. Impacts are evaluated based on context, duration, intensity, and type, and whether they are direct, indirect, or cumulative. In addition, impairment to park resources and values is considered.

The following guidelines were used to identify the context, duration, intensity (or magnitude), and type of impact for each project alternative.

• Context. The context considers whether the impact would be local or regional. For the purposes of this analysis, local impacts would be those that occur within Yosemite Valley, unless otherwise noted.

• Duration. The duration of an impact is noted as either short-term or long-term and defined in a range of years.

• Intensity. Indicators of the intensity of an impact, whether it is negligible, minor, moderate, or major, are included in the impact analysis and specifically defined by topic area in the methodology section that follows.

• Type. The type of impact refers to whether the effect is considered beneficial or adverse. Beneficial impacts would improve resource conditions. Adverse impacts would deplete or negatively alter resources. Mitigating actions listed in Chapter II would be taken during implementation of the action alternatives. With the exception of the cultural resource analysis, all impacts have been assessed under the assumption that mitigating measures have already been implemented.

Alternative 1 (the No Action Alternative) describes the continuation of current management actions in Yosemite Valley. In this case, this includes the ongoing repairs and maintenance of existing Valley utilities, including repairs to the Valley wastewater system required under a Cleanup and Abatement Order issued by the California Regional Water Quality Control Board. This alternative provides a baseline from which to compare other action alternatives, to evaluate the magnitude of proposed changes, and to measure the environmental effects of these changes.

Cumulative Impacts

The CEQ describes a cumulative impact as follows (Regulation 1508.7):

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

The cumulative projects addressed in this analysis include past actions, present actions, as well as any planning or development activity currently being implemented or planned for implementation in the reasonably foreseeable future. Cumulative actions are evaluated in conjunction with the impacts of an alternative to determine if they have any additive effects on a particular resource. Because most of the cumulative projects are in the early planning stages, the evaluation of cumulative impacts was based on a general description of the project. Appendix H contains the list of cumulative projects included in the cumulative impacts analysis.

Impairment

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

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

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

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

• Identified as a goal in the park’s General Management Plan or other relevant National Park Service planning documents

The evaluation of impairment of park resources was based on the type and intensity of impacts and the types of resources affected. Overall, beneficial impacts would not constitute impairment. With respect to the intensity of impacts, negligible and minor, adverse impacts are not of sufficient magnitude to constitute impairment. Moderate and major adverse impacts may constitute impairment but do not automatically do so. Rather, these impacts must be analyzed with respect to the three bulleted criteria above. Impairment is generally considered for geologic, hydrological, biological, cultural, and scenic resources and recreation. Impairment is addressed in the conclusion section of each impact topic under each alternative.

Methods and Assumptions

This section presents the methods and assumptions used to conduct the environmental impact analyses for each resource topic.

Soils

• This document analyzes impacts to soils and restoration of impacted soils. The soils data used were gathered from the park’s geographic information system (GIS). Types of soil impacts include soil removal, soil profile mixing, soil compaction, soil erosion, soil contamination, and soil restoration and revegetation activities. Activities that may result in soil impacts include the construction of buildings, parking areas, roads, trails, utilities, and other facilities. In the areas affected by the East Yosemite Valley Utilities Improvement Plan, most soils have been previously disturbed by construction of utility lines, roadways, or other facilities
  .

• Soil Removal. Paving activities and construction remove and cover the soil surface and can result in changes to basic soil properties. Excavation and removal of the soil surface would result in a long-term impact because the basic soil properties, which have taken thousands of years to develop, would have been removed. Covering the surface reduces water movement and minimizes the opportunity for the normal physical and chemical soil processes.

• Soil Profile Mixing. Soil excavation and redistribution results in removal or mixing of the soil profile and disrupts soil structural characteristics, interrupting the chemical, physical, and biological processes that naturally occur in the soil. The level of change is dependent on the level of the alteration. It may take many years to redevelop the soil profile.

• Soil Compaction. Soil compaction may occur as a result of construction activities or in areas of intensive use such as trails, campgrounds, and picnic areas. Wetland soils are very susceptible to compaction effects. Soil compaction reduces infiltration rates, thereby increasing surface runoff and the potential for erosion. Deep compaction of soils may impede subsurface flow. In turn, these effects could alter soil chemical processes such as nutrient transfer, biological processes such as root development and microbial patterns, and physical processes such as soil structure. Vegetation growth on compacted soils is often limited due to low infiltration and poor root penetration.

• Soil Erosion. Removal of vegetation through grading activities or pedestrian use may result in accelerated erosion of the soil surface. Soils on steep slopes and along watercourses are especially susceptible to erosion.

• Soil Contamination. The addition of chemical constituents into the soils as a result of pavement installation, untreated runoff from paved surfaces, or from incidental spills, may alter micro- or macro-organism populations, diversity, and dynamics. Machinery involved with construction activities may deposit small amounts of natural and synthetic petrohydrocarbons onto soils through equipment failure or normal operations.

• Soil Restoration. Ecological restoration that would minimize erosion potential, increase organic matter in the soil, and/or allow more natural groundwater flows within soils, would be considered a beneficial effect. Short-term adverse effects may occur during site restoration activities where construction equipment may compact soils, temporarily eliminate groundcover vegetation, and cause potential erosion from surface water runoff over the exposed soils.

Duration of Impact

The duration of soils impacts was characterized as short-term or long-term. Short-term impacts could be restored when project construction is completed and were considered to last 20 years or less. Long-term impacts were considered to last over to 20 years.

Intensity of Impact

The evaluation of the intensity of impacts on soils focuses on hydric soils, resilient soils, and other soils. Hydric soils commonly form in wetlands and can be associated with rare, threatened, or endangered plants. Hydric soils usually form under sufficiently wet conditions to develop anaerobic conditions and support vegetation adapted to wet conditions. Hydric soils are protected by wetland protection policies such as Executive Order 11990, Protection of Wetlands and NPS Director’s Order #77-1, Wetland Protection.

Resilient soils are more capable of withstanding alteration without permanent deformation. These soils tend to be able to recover more quickly from alteration. Generally, these soils do not have major use limitations or severely restrictive physical attributes.

Soils classified as other include those that are not identified as hydric or resilient soils. Generally, these soils have more limitations on use because of steep slopes or other physical attributes. They may require more intensive management or engineered mitigation measures for development, as compared to resilient soils. Other soils are generally more abundant or do not support plant communities that are rare or especially diverse.

Impact intensity was characterized as negligible, minor, moderate, or major. Definitions of impact intensities for various soil types are provided in table IV-1.

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Table IV-1

Soil Impact Intensity Definitions
 

Type of Impact

Beneficial impacts to soils protect or restore natural soil conditions, including abiotic and biotic components, soil structure, and moisture. Adverse impacts would result in degradation of chemical, physical, abiotic, or biotic soil components.

Water Resources

Impacts on hydrology, floodplain values, and water quality are discussed under this resource topic. Hydrology refers to hydrologic processes such as flooding, erosion and deposition, and river or stream channel movement. Particular attention was given to alterations or restoration of water flow (e.g., placement or removal of facilities in the Merced River channel). Floodplain values are attributes of flooding that contribute to ecosystem quality, such as recharge of riparian groundwater. Particular attention was given to alterations or restoration of the floodplain (e.g., placement or restoration of facilities in a floodplain).

Water quality refers to the suitability of surface water for recreational use and wildlife habitat , particularly the enhancement or degradation of water quality. The National Park Service Freshwater Resource Management Guidelines (found in NPS-77) requires the National Park Service to “maintain, rehabilitate, and perpetuate the inherent integrity of water resources and aquatic ecosystems.” The Clean Water Act requires the National Park Service to “comply with all Federal, State, interstate, and local requirements, administrative authority, and process and sanctions respecting the control and abatement of water pollution.”

Duration of Impact

Short-term impacts are usually considered to be less than two years in duration (e.g., construction projects). Long-term impacts remain after an alternative has been implemented and are usually longer than two years in duration. Since the full implementation of an alternative would take place over a number of years, this section frequently assesses the duration of individual actions of the alternative (e.g., removal of structures, site restoration, construction of new structures) instead of full implementation of the alternative.

Intensity of Impact

Negligible impacts would be imperceptible or not detectable. Minor impacts would be slightly perceptible and localized, without the potential to expand if left alone. Moderate impacts would be apparent and have the potential to become larger. Major impacts would be substantial, highly noticeable, and may be permanent.

Type of Impact

Adverse impacts alter natural hydrologic conditions (e.g., impede flood flows, cause unnatural erosion or deposition, etc.) or degrade water quality (e.g., increase pollution or bacteria levels from recreational use). Beneficial impacts are those that restore natural hydrologic conditions (e.g., remove impediments to flood flows, stabilize riverbanks, etc.) or improve water quality (e.g., reduce nonpoint source pollution).

Context of Impact

Localized impacts would occur in the immediate vicinity of an action or in a nearby area indirectly affected by the action (e.g., radiating impacts of concentrated visitor use). Regional impacts would occur over a large area, such as Yosemite National Park or the Sierra Nevada. Many water quality impacts are regional because an action could potentially affect water quality downstream.

Floodplains

National Park Service policy is to protect natural floodplain values and functions, and to minimize risk to life or property by avoiding the use of the regulatory floodplain whenever there is a feasible alternative location. Impacts are evaluated for this resource topic based on the potential to avoid loss of life and property during major floods. The Water Resources section addresses potential impacts on floodplain values and hydrology.

The National Park Service manages floodplains in accordance with Executive Order 11988 and Procedures Manual #77-2, National Park Service Floodplain Management (NPS 2002). The regulatory floodplain is defined as the 100-year, 500-year, or maximum possible flood depending on the type of activity and the amount of risk inherent in the nature of flooding at a location. Generally, the regulatory floodplain is the 100-year flood for most park functions in environments like Yosemite Valley. The 100-year floodplain in Yosemite Valley from Happy Isles to Swinging Bridge was mapped based on the flood frequency analysis prepared by the U.S. Geological Survey after the January 1997 flood (Cella Barr Associates 1998, Stantec Consulting 2000). From Swinging Bridge to Pohono Bridge the floodplain has not been mapped and is based upon the extent of the January 1997 flood. For critical actions such as schools, hospitals, and large fuel storage facilities, the regulatory floodplain is defined as the 500-year floodplain. Some facilities such as picnic areas and day-visitor parking are exempt from the National Park Service guidelines because they are often located near water for the enjoyment of visitors and do not involve overnight occupation.

When there is no practicable alternative to placement of facilities in a floodplain location, National Park Service policy permits the use of the floodplain when there are compelling reasons for doing so, when the level of impact to natural floodplain processes is acceptable, and when mitigation is provided to protect human life and property. A statement of findings must be written to document a decision to place facilities within a floodplain.

Duration of Impact

Short-term impacts would be those that occur over a period of less than one year. Long-term impacts would be those occurring for more than one year. All the impacts evaluated would be considered long-term. The risk posed to construction personnel working in the floodplain (short-term) was considered too small to warrant evaluation.

Intensity of Impact

Beneficial and adverse impacts of individual actions in each alternative were assigned intensities as they relate to effects on life/safety and property in the floodplain. Definitions of impact intensities are provided in table IV-2.

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Table IV-2

Floodplain Impact Intensity Definitions
 

Type of Impact

The removal of structures from the 100-year floodplain was considered a beneficial impact to human life or property. Development of new Class I or Class II actions (non-exempted facilities) in the 100-year floodplain was considered an adverse impact to human life or property.

Wetlands

The results from wetland delineations conducted in Yosemite Valley in 2002 and 2003 and the Yosemite Valley vegetation map (NPS 1994b) were used to evaluate impacts on wetlands. These results, which indicate the location of wetlands, were compared to each action alternative to determine the area of potential impact.

The wetland protection statutes that guide the National Park Service include Executive Order 11990, Protection of Wetlands; Director’s Order #77-1, Wetland Protection, and its accompanying Procedural Manual #77-1; Clean Water Act Sections 10 and 404; and the “no net loss” goal outlined by the White House Office on Environmental Policy in 1993. Executive Order 11990 requires agencies to minimize the destruction, loss, or degradation of wetlands. National Park Service’s Director’s Order #77-1 and Procedural Manual #77-1 provide specific procedures for carrying out Executive Order 11990. Section 10 of the Rivers and Harbors Act and Section 404 of the Clean Water Act authorize the U.S. Army Corps of Engineers to grant permits for construction and disposal of dredged material in waters of the United States. This analysis considers whether proposed actions could breach applicable federal laws, regulations, or executive orders.

Duration of Impact

The expected duration of impacts has been defined as long-term or short-term. Short-term impacts would last up to 20 years following the implementation of an alternative, and long-term impacts would last longer than 20 years after implementation of an alternative.

Intensity of Impact

Three primary measures were used to evaluate the intensity of impacts on wetlands: the size and type of the wetland, the integrity of the wetland, and the connectivity of the wetland to adjacent habitats.

The intensity of impacts has been described as negligible, minor, moderate, or major. Negligible impacts would be imperceptible or not detectable. Minor impacts would be slightly detectable, localized within a small area, and would not affect the overall viability of wetlands in the park. Moderate impacts would be apparent and have the potential to become major impacts. Major impacts would be substantial, highly noticeable, and could become permanent.

Type of Impact

Adverse impacts would degrade the size, integrity, or connectivity of wetlands. Conversely, beneficial impacts would enlarge the size or enhance the integrity and connectivity of wetlands.

Vegetation

Impacts on vegetation communities were assessed in terms of duration, type, and intensity in site-specific, parkwide, and regional contexts.

Duration of Impact

Long-term impacts are defined as those that can be detected for longer than 20 years. Short-term impacts are defined as those lasting less than 20 years.

Intensity of Impact

Three primary parameters were used to evaluate the intensity of impacts on vegetation: (1) changes in the geographic extent and continuity of plant communities, (2) changes in the integrity of plant communities, and (3) the resilience of affected plant communities.

The geographical extent of plant communities within the project area was determined from vegetation data available in the park’s GIS. To measure proposed development, utility corridors and utility infrastructure sites were drawn onto maps generated on the GIS. The area affected was calculated based on assumptions regarding corridor widths and substation or transformer sizes. The relative extent of a plant community was determined by comparison with similar communities within Yosemite National Park.

Human use impacts such as recreational use and foot traffic can extend beyond developed areas and affect plant community size and continuity. Human use can disturb or compact soils, create conditions favorable for non-native species or introduce non-native species, and trample native vegetation cover. Human use impacts that extend beyond development boundaries were considered as factor in determining the intensity of impacts on vegetation.

New development within an otherwise intact and undisturbed area may fragment or disassociate plant communities. Small areas of restoration surrounded by existing or new development may constitute a lesser beneficial impact on plant communities than restoration of a small area adjacent to a larger intact community. In general, reducing and limiting fragmentation and maintaining connections within and among plant communities can minimize adverse effects on plant communities.

The evaluation of the integrity of plant communities was based on:

• Biodiversity

• Opportunities for natural processes to occur such as fire and flooding

• Exotic species introduction and spread

• Resilience of the plant community

In this document, biodiversity refers to the diversity of communities within an ecosystem, the diversity of species within a community, and genetic variation among individual species. Measures of biodiversity may include plant community structure and composition, connectivity of ecosystems, variation in age, structure (density and arrangement), individual species composition and abundance, and the presence or absence of natural structural layers.

Natural processes such as fire and flooding sustain many plant communities. This impact analysis considered whether changes would occur to opportunities for natural processes (or management options such as prescribed burning) to take place. For example, new development may prohibit opportunities for prescribed natural fire.

Non-native species can alter soil chemical and physical properties, hamper native species establishment, and ultimately alter native plant community structure and function. This impact analysis considered whether proposed actions would favor the establishment of non-native species, as well as the ability to contain and reverse non-native plant infestation.

Resilient plant communities are more capable of withstanding anthropogenic alteration without long-term deformation. These communities tend to be able to recover more quickly from alteration.

Negligible impacts would have no measurable or perceptible changes in plant community size, continuity, or integrity. Minor impacts would be measurable or perceptible and localized within a relatively small area and the overall viability of the plant community would not be affected. Moderate impacts would cause a change in the plant community (e.g., size, continuity, and integrity); however, the impact would remain localized. The change would be measurable and perceptible, but could be reversed. Major impacts would be substantial, highly noticeable, and could be permanent in their effect on plant community size, diversity, continuity, or integrity.

Type of Impact

Impacts were classified as adverse if they would reduce the size, continuity, or integrity of a plant community. Conversely, impacts were classified as beneficial if they would increase the size, continuity, or integrity of a plant community.

Wildlife

This analysis addresses the effects of alternatives on wildlife and their habitat, as represented by general vegetation types. The correlation of vegetation impacts and effects on wildlife is also described. Adverse effects to wildlife without modifications to wildlife habitat are also considered.

In general, adverse effects on wildlife can be minimized by reducing and limiting habitat fragmentation; that is, by preserving and restoring large areas of habitat, patches of habitat, and maintaining connections within and among habitat types. Larger patches of habitat tend to support higher numbers and diversity of wildlife species than smaller ones, and connections between habitat patches enable the movement of wildlife between areas, enhancing reproduction and survival. Small patches of habitat can serve as stepping-stones for wildlife moving between larger blocks.

The value of habitat patches for wildlife is also affected by adjacent human activities and development. Severe disruption of habitat between patches can impede wildlife movements. Impacts radiating into habitat patches (referred to in the analysis as radiating impacts), such as light, noise, non-native species, and human use, can affect habitat quality. This impact is less severe in larger habitat patches because the ratio of volume to edge habitat is greater than in smaller patches, and wildlife preserve a core of habitat that is more isolated from radiating impacts. These same factors of radiating impacts also increase the effect of new development beyond the boundaries of the habitat directly affected by removal and/or modification activities.

Ultimately, the value of a restored area or the impact of a developed area to wildlife is determined by the characteristics of the species affected. Home-range size, tolerance of human disturbance, and life-history characteristics determine whether a species reoccupies a restored area or abandons a disturbed area.

Impacts on wildlife have been assessed in terms of changes in the amount and distribution of wildlife habitat, the size and connectivity of habitat, the integrity of the site (including past disturbance), the potential for habituation of wildlife to humans, and the relative importance of habitats.

Habitat types with high value to wildlife were identified through a combination of evaluation methods. Habitat types were evaluated using the California Wildlife Habitat Relationships System based on the number of species unique to each habitat type, the number of special-status species expected in each type, and the scarcity of the habitat in the park. This model indicated that changes to two rare habitat types in the park (fresh emergent wetland and lacustrine) would have the most effect on wildlife (Chow et al. 1994). This evaluation was broadened by an overview of habitat types in the park and the Sierra Nevada that have a recognized high value to wildlife and have undergone extensive reduction and degradation. Such habitats include meadows, riparian, and California black oak woodland (NPS 1994a; UC Davis 1996) Overlaying this evaluation of habitat types, however, was an assessment of the degree to which actions increased or decreased habitat fragmentation (the size of the area affected, its relationship and connection to other habitat areas, and the level of human disturbance that would continue to affect its quality). The home ranges of those species and their tolerance of human disturbance also affect the value of habitat areas to individual species. For instance, the restoration of a 10-acre area could increase habitat for small rodents, but probably would not substantially benefit species with relatively large home ranges such as black bears or mountain lions.

Actions were also assessed as to their potential for causing human/wildlife conflicts resulting from increased recreational disturbances in sensitive habitats such as meadows, and the introduction of unnatural food sources. Such impacts can lead to changes in animal behavior, increased mortality, and altered habitat use.

Duration of Impact

Short-term impacts would be expected to last for less than 20 years. All short-term impacts to wildlife and habitat from implementation of an alternative would relate to construction activities and their immediate effects on wildlife. These impacts end with cessation of construction activity, or soon thereafter, and include the following:

• Noise, dust, and light emanating from construction sites could affect the use of surrounding habitats by wildlife.

• Vegetation removed, trampled, or run-over during temporary use of some habitat as areas for staging of machinery or materials would affect wildlife until such areas could be restored after the project.

• Diversion of water flows during construction would result in unnatural drying or wetting of habitats adjacent to sites.

• Wildlife could be killed by traffic or machinery associated with construction.

• Pits and trenches could entrap wildlife, resulting in their death.

• Spills of fuel, oil, hydraulic fluid, antifreeze, and other toxic chemicals could affect wildlife, especially those in aquatic environments.

• Construction personnel, at in-park residences or at work sites, could provide a source of human food to wildlife, resulting in conditioning of wildlife and in human/wildlife conflicts.

Long-term impacts have been defined as those lasting 20 years or longer. Subsequent impact analyses focused primarily on long-term effects of implementation during the operational lifetime of the alternatives that result in changes in the abundance, diversity, and distribution of wildlife.

Intensity of Impact

Negligible impacts are impacts that would not be measurable or perceptible. Minor impacts would be measurable or perceptible and would be localized within a relatively small area; however, the overall viability of the resource would not be affected. Without further impacts, negative effects would be reversed, and the resource would recover. Moderate impacts would be sufficient to cause a change in the resource (e.g., abundance, distribution, quantity, or quality); however, the impact would remain localized. The change would be measurable and perceptible, but negative effects could be reversed. Major impacts would be substantial, highly noticeable, and could be permanent without active management.

Type of Impact

Impacts were classified as adverse if they would negatively affect the size, continuity, or integrity of wildlife habitat, or result in unnatural changes in the abundance, diversity, or distribution of wildlife species. Conversely, impacts were classified as beneficial if they would positively affect the size, continuity, or integrity of wildlife habitat.

Special-Status Species

Wildlife

This analysis includes species listed under the Endangered Species Act as threatened or endangered; species that are Candidates for listing under the Endangered Species Act; species given Species of Concern status by the United States Fish and Wildlife Service; species listed by the State of California as threatened, endangered, or species of concern; species considered rare by the California Native Plant Society; and locally rare species of special importance to the park. The impact evaluation for special-status wildlife species was based on the following: (1) the known or likely occurrence of a species or its preferred habitat in the vicinity of the project area; (2) the direct physical loss or adverse modification of habitat; (3) the effective loss of habitat (through avoidance or abandonment) due to construction activity or noise, or the species’ sensitivity to human disturbance.

Habitat fragmentation is also a critical factor for special-status species. Restored blocks of habitat should be large enough to support viable populations, and intact habitat should not be reduced or affected to the point that it would no longer support viable populations. A more detailed discussion of impact duration, intensity, and type is included in the preceding Wildlife section.

Plants

This analysis includes species listed under the Endangered Species Act as threatened or endangered; species that are Candidates for listing under the Endangered Species Act; species given Species of Concern status by the United States Fish and Wildlife Service; species listed by the State of California as threatened, endangered, rare, or species of concern; and locally rare species of special importance to the park. The impact evaluation for special-status plant species was based on the following: (1) the known or likely occurrence of a species or its preferred habitat in the vicinity of the project area; (2) the direct physical loss of habitat; (3) the effective loss of habitat through loss of habitat features such as surface water flows. Impact evaluations determined the location of species in proximity to the proposed project disturbance and assessed the sensitivity of a species to impacts (considering rarity, resilience, population size, and distribution of species throughout the park).

Duration of Impact

The expected duration of impacts has been defined as long-term or short-term for special-status wildlife and plant species. Long-term impacts would be defined as those lasting 20 years or longer and short-term impacts as those lasting less than 20 years.

Intensity of Impact

The intensity and magnitude of impacts on special-status vegetation  and wildlife species have been described as negligible, minor, moderate, or major. Negligible impacts would be imperceptible or not detectable. Minor impacts would be slightly detectable, localized within a relatively small area, and would not affect the overall viability of resources in the park; without further impacts, adverse effects would be reversed, and the resource would recover. Moderate impacts would be sufficient to cause a change in the resource (e.g., abundance, distribution, quantity, or quality), but would remain localized; they would be readily apparent. Major impacts would be substantial, highly noticeable, and affect larger areas.

Type of Impact

Impacts were classified as adverse if they would negatively affect population size, habitat size and continuity, or integrity of a special-status species. Conversely, impacts were classified as beneficial if they would positively affect population size or the size, continuity, or integrity of habitat.

Air Quality

The air quality analysis was based on a qualitative analysis of air emissions from construction and removal activities as well as operations of utility facilities long-term. The creation of pollutants resulting from the implementation of an alternative can contribute to an impact on air quality; however, air quality is a regional issue that is influenced by factors outside the immediate area. In addition, many air quality issues are related to non-construction vehicles and air quality analysis often focuses on vehicle emissions related to increases or decreases in traffic volumes. Since this project is not expected to affect non-construction vehicle trips or traffic volumes, non-construction vehicular emissions are not addressed. However, regional pollutant transport issues were evaluated in the context of regional cumulative impacts.

Many localities have emissions-based regulations in place; however, emissions-based criteria for evaluating the significance of construction-phase impacts have not been established by the National Park Service or the Mariposa County Air Pollution Control District. In the absence of such recommendations, the typical approach is to qualitatively evaluate the significance of temporary construction-related impacts. The analysis of effects was qualitative, and professional judgment was applied to reach reasonable conclusions as to the context, duration, and intensity of potential impacts. When possible, mitigation measure(s) were incorporated into the project to reduce the intensity of adverse effects.

Air quality impacts were evaluated in terms of intensity and duration and whether the impacts were considered beneficial or adverse. Cumulative effects on air quality were also considered based on past, present, and reasonably foreseeable future actions occurring in Yosemite National Park, in combination with the potential air quality effects of each alternative.

Duration of Impact

The duration of the impact considered whether the impact would occur in the short term or long term. Generally, short-term impacts are temporary, transitional and associated with construction and removal activities. Long-term impacts are typically those effects that continue to occur after construction and last 10 years or more and could be considered permanent.

Intensity of Impact

The intensity of an impact considers whether the impact is judged negligible, minor, moderate, or major relative to air quality conditions associated with the No Action Alternative.

Type of Impact

Impacts were considered beneficial or adverse to air quality. Beneficial air quality impacts would reduce emissions or lower pollutant concentrations, while adverse impacts would increase emissions or raise pollutant concentrations.

Noise

Sound impacts related to the project alternatives are expected to be limited to construction-related activities. A qualitative assessment of noise impacts associated with construction activities associated with implementation of the alternatives was developed using professional judgment. There are two types of sensitive receptors of construction noise: visitors and residents. Sound is considered a noise impact only if it is experienced by a noise sensitive receptor. The sound-attenuating impacts of topography and vegetation are not factored into this analysis.

Duration of Impact

Short-term impacts would be temporary impacts that typically occur during construction activities. Long-term impacts would be impacts that continue to occur after construction and typically last 10 years or more and would be considered permanent changes.

Intensity of Impact

The level of impact (negligible, minor, moderate, or major) of sound changes from the No Action Alternative to the action alternatives was evaluated using the following definitions. A negligible impact indicates the change in sound levels would not be perceptible. A minor impact indicates the change in sound levels would be perceptible, but not likely to have a substantial annoyance effect on visitors or residents in the area. A moderate impact indicates the change in sound levels would be easily perceptible and likely to result in annoyance to some park visitors and residents. A major impact indicates the change in sound levels would be very perceptible and likely to annoy most park visitors and residents who experience it.

Type of Impact

Beneficial impacts are those impacts that result in less noise, and adverse impacts are those impacts that result in more noise.

Cultural Resources

This impact analysis methodology applies to three types of cultural resources: archeological sites, traditional cultural resources, and cultural landscape resources (including individually significant historic structures and historic districts).

Section 106 of the National Historic Preservation Act requires a federal agency to take into account the effects of its undertakings on properties included in, eligible for inclusion in, or potentially eligible for inclusion in the National Register of Historic Places, and provide the Advisory Council on Historic Preservation the reasonable opportunity to comment. A Programmatic Agreement was developed in 1999 among the National Park Service at Yosemite, the California State Historic Preservation Officer, and the Advisory Council on Historic Preservation, in consultation with American Indian tribes and the public, to take into account the effects of park planning and operations on historic properties. This agreement supplemented the 1995 Nationwide Programmatic Agreement among the National Park Service, the Advisory Council on Historical Preservation, and the National Conference of State Historic Preservation Officers.

The methodology for assessing impacts to historic resources is based on stipulations V through VIII of the Programmatic Agreement. This includes: (1) establishing an Area of Potential Effect; (2) assessing the background information regarding historic properties within this area and conducting any necessary surveys, inventories, and resource evaluations; (3) comparing the location of the impact area 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 effects; (5) assessing those effects according to procedures established in the Advisory Council on Historic Preservation’s regulations; and (6) considering ways to avoid, reduce, or mitigate adverse effects.

Cultural resource impacts in this document are described in terminology consistent with the regulations of the Council on Environmental Quality, and in compliance with the requirements of the NEPA, Section 106 of the National Historic Preservation Act, and the 1999 Programmatic Agreement regarding the Planning, Design, Construction, Operations, and Maintenance of Yosemite National Park. The Section 106 determination of effect for the undertaking (implementation of the alternative), required by the Programmatic Agreement, is included in the Section 106 Summary for each alternative, presented later in this chapter.

Type of Impact

Impacts are considered to be either adverse or beneficial to historic properties (cultural resources) when analyzed under NEPA. However, impact type is not viewed this way when conducting analysis under Section 106 of the National Historic Preservation Act. For the purposes of assessing effects to historic properties under the National Historic Preservation Act, effects are either adverse or not adverse. Effects under both NEPA and the National Historic Preservation Act are considered adverse when they diminish the significant characteristics of a historic property.

Impacts can be either direct or indirect. Direct impacts result from specific actions, such as demolition of historic structures. Indirect impacts generally occur after project completion, and are a result of changes in visitor-use patterns or management of resources fostered by implementation of an action.

Duration of Impact

Impacts to historic properties (cultural resources) could be of short term, long term, or permanent duration. Analysis of the duration of impacts is required under NEPA, but is not required and is not usually considered in assessing effects in terms of National Historic Preservation Act.

Intensity of Impact

The intensity of an impact on a cultural resource can be defined as negligible, minor, moderate, or major. Negligible impacts would be barely perceptible changes in significant characteristics of a historic property. Minor impacts would be perceptible and noticeable, but would remain localized and confined to a single element or significant characteristic of a historic property (such as a single archeological site containing low data potential within a larger archeological district, or a single contributing element of a larger historic district). Moderate impacts would be sufficient to cause a noticeable but not substantial change in significant characteristics of a historic property (such as an archeological site with moderate data potential or a small group of contributing elements within a larger historic district). Major impacts would result in substantial and highly noticeable changes in significant characteristics of a historic property (such as an archeological site with high data potential or a large group of contributing elements within a larger historic district).

Mitigation

NEPA also calls for a discussion of the appropriateness of mitigation and an analysis of the effectiveness of mitigation. A reduction in intensity of impact from mitigation is an estimate of the effectiveness of this mitigation under the NEPA. It does not suggest that the level of effect, as defined by implementing regulations for Section 106 of the National Historic Preservation Act, is similarly reduced. Although adverse effects under Section 106 may be mitigated, the effects remain adverse.

Mitigation of effects to cultural resources in this document is based on the 1999 Programmatic Agreement and includes the avoidance of adverse effects or the application of one or more standard mitigation measures as described in stipulations VII (C) and VIII of the Programmatic Agreement. Avoidance strategies may include the application of the Secretary of the Interior’s Standards and Guidelines for Archeology and Historic Preservation (Secretary’s Standards; USDOI 1983), design methods such as vegetation screening when placing new facilities in a historic district, and the development of guidelines to ensure compatibility between new and existing facilities. Mitigation of adverse effects to archeological properties may include avoidance and data recovery. Stipulation VIII of the Programmatic Agreement requires that the National Park Service notify the State Historic Preservation Officer, culturally associated American Indian tribes, and certain members of the public of its decision to implement standard mitigation measures as described in Stipulation VIII (A) for individual actions having an adverse effect on historic properties.

Presented below are the specific discussions of duration, intensity, and type of impacts to cultural resources, and a description of typical mitigation measures.

Archeological Resources

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 (cf. 36 CFR 60.4).

Type and Duration of Impact

Any change in the physical attributes of an archeological site is irreparable and considered adverse and of permanent duration. Adverse impacts to archeological resources most often occur as a result of earthmoving activities within an archeological site area, soil compaction or increased erosion, unauthorized surface collection, or vandalism. Beneficial impacts to archeological resources can occur when patterns of visitor use or management action are changed near archeological resources such that an ongoing impact, which would otherwise continue to degrade archeological resources, is reduced or arrested. Direct impacts can occur as a result of grading, trenching, or other activities that damage the structure of an archeological site. Indirect impacts can occur as a result of increasing visitor activity or management action near an archeological site, leading to things such as artifact collection, accelerated soil compaction, and erosion.

Intensity of Impact

The intensity of impact to an archeological resource would depend upon the potential of the resource to yield important information, as well as the extent of the physical disturbance or degradation. For example, major earthmoving at an archeological site with low data potential might result in a minor, adverse impact. Negligible impacts would be barely perceptible and not measurable, and would usually be confined to archeological sites with low data potential. Minor impacts would be perceptible and measurable, and would remain localized and confined to archeological site(s) with low to moderate data potential. Moderate impacts would be sufficient to cause a noticeable change and would generally involve one or more archeological sites with moderate to high data potential. Major impacts would result in substantial and highly noticeable changes, involving archeological site(s) with high data potential.

Mitigation

For archeological resources, mitigation includes avoidance of sites through project design, or recovery of information that makes sites eligible for inclusion in the National Register of Historic Places. According to Stipulation VII (C) of the 1999 Programmatic Agreement, effects to archeological resources are considered not adverse for purposes of Section 106 of the National Historic Preservation Act if data recovery is carried out in accordance with the Archeological Synthesis and Research Design (Hull and Moratto 1999).

Traditional Cultural Resources

Traditional cultural resources are considered eligible for inclusion in the National Register of Historic Places as traditional cultural properties (or places) when: (1) they are rooted in a community’s history and is important for maintaining the continuing cultural identity of the community; and (2) the property (ies) meet National Register criteria for significance and integrity.

Type of Impact

Impacts to traditional cultural resources occur as a result of changes in the physical characteristics, access to, or use of resources, such that the cultural traditions associated with those resources are changed or lost. Beneficial impacts can occur when intrusive facilities or visitor or management activities are removed from a traditional use area; when ecological conditions are improved at a gathering area such that the traditionally used resource is enhanced; or when access for culturally associated American Indian people is enhanced. Adverse impacts occur when physical changes to a traditionally used resource or its setting degrade the resource itself, or degrade access to or use of a resource.

Duration of Impact

Impacts are considered short-term if they represent a temporary change in important vegetation or temporarily restrict access to an important resource and do not disrupt the cultural traditions associated with that resource for a noticeable period of time. They are considered long term if they involve a change in important vegetation or cultural feature, or the addition of a new facility or visitor use that would change the physical character of or access to a resource for a noticeable period of time. This period of time would vary by resource type and traditional practitioners. These long-term changes would disrupt cultural tradition(s) associated with the affected resource, but the disruption would not alter traditional activities to the extent that the important cultural traditions associated with the resource are lost. Permanent impacts to traditional cultural resources would involve irreversible changes in important resources such that the ongoing cultural traditions associated with those resources are lost.

Intensity of Impact

The intensity of impacts to a traditional cultural resource would depend on the importance of the resource to an ongoing cultural tradition, as well as the extent of physical damage or change. Negligible impacts would be barely perceptible and not measurable, and would be confined to a small area or single contributing element of a larger National Register district (such as the proposed traditional cultural property). Minor impacts would be perceptible and measurable and remain localized and confined to a single contributing element of a larger National Register district. Moderate impacts would be sufficient to cause a change in a significant characteristic of a National Register district or property, and/or would generally involve a small group of contributing elements in a larger National Register district. Major impacts would result in substantial and highly noticeable changes in significant characteristics of a National Register district or property, and/or would involve a large group of contributing elements in a larger National Register district and/or an individually significant property.

Mitigation

The National Park Service has initiated consultation and will continue to consult with culturally associated American Indian tribes according to stipulations of the 1999 Programmatic Agreement, as well as specific agreements such as the October 17, 1997 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 strategies to mitigate impacts on traditional cultural resources. Such strategies could include pre-construction cultural surveys of corridors, salvage of specific plants, salvage and reuse of topsoil, and tribal participation in development, implementation, and maintenance of revegetation plans for disturbed areas.

Cultural Landscape Resources, Including Historic Sites and Structures

Type of Impact

Impacts to cultural landscape resources result from physical changes to significant characteristics of a resource or its setting. Beneficial impacts can occur as a result of restoration or rehabilitation of resources, or removal of incompatible or noncontributing facilities. Direct, adverse impacts generally occur as a result of modifying a significant characteristic of a historic structure or landscape resource; removal of a significant structure or landscape resource; or addition of new, incompatible facilities in proximity to a historic site or structure. Indirect adverse impacts can also occur following project completion. These impacts are generally associated with changes in historic vegetation, or continued deterioration of historic structures. They are considered indirect impacts, as they are not directly associated with project construction, but rather result from increased visitor use or change in management of resources fostered by the completed plan.

Duration of Impact

Impacts to historic structures and cultural landscape resources are considered short-term if they involve activities such as temporary removal of vegetation or other contributing resources, road closures, or prescribed burns, where the impacts are noticeable for a period of from one to five years. Other examples of short-term impacts to historic structures include constructing scaffolding surrounding a building during rehabilitation work, or minor deterioration in historic fabric that is repairable as part of routine maintenance and upkeep. Impacts are considered long term if they involve a reversible change, lasting from five to 20 years, in a significant characteristic of a historic structure or landscape. These changes could include such actions as alteration of contributing resources or construction of an incompatible building addition or adjacent facility. Permanent impacts to a historic structure or landscape resources would include irreversible changes in significant characteristics, such as removal of contributing resources; restoration of natural systems and features; irreversible removal of historic fabric that changes the historic character of a property; or demolition of a historic structure.

Intensity of Impact

Negligible impacts are barely perceptible, not measurable, and confined to small areas or a single contributing element of a larger National Register district. Minor impacts would be perceptible and measurable but remain localized and confined to a single contributing element of a larger National Register district. Moderate impacts would be sufficient to cause a change in a significant characteristic of an individually significant historic structure, or would generally involve a single or small group of contributing elements in a larger National Register district. Major impacts would result from substantial and highly noticeable changes in significant characteristics of an individually significant historic structure, or would involve a large group of contributing elements in a National Register district.

Mitigation

Mitigation measures for historic structures and cultural landscape resources include measures to avoid impacts, such as rehabilitation and adaptive reuse, designing new development to be compatible with surrounding historic resources, and screening new development from surrounding historic resources. In situations where a historic structure was proposed for removal, the National Park Service would first consider options for relocating the structure to another location in the park for adaptive reuse. Standard mitigation measures, as defined in the 1999 Programmatic Agreement, include documentation according to standards of the Historic American Buildings Survey/Historic American Engineering Record (HABS/HAER) as defined in the Re-Engineering Proposal (October 1997). The level of this documentation, which includes photography and a narrative history, would depend on the significance of a resource (national, state, or local) and the nature of the resource (an individually significant structure, contributing elements in a cultural landscape or historic district, etc.). When a historic structure is slated for demolition, architectural elements and objects may be salvaged for reuse in rehabilitating similar structures, or they may be added to the park’s museum collection. In addition, the historical alteration of the human environment and reasons for that alteration would be interpreted to park visitors.

Scenic Resources

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 determined impacts on scenic resources by examining the potential effects of the project alternatives on the landscape character and/or features and how any changes may be experienced (such as visibility and viewpoints).

Impacts on scenic resources were examined and determined by:

• Comparing the existing visual character of the landscape in terms of the color, contextual scale, and formal attributes of landscape components and features, and the degree to which actions that may result from the proposed action 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 substantial changes that would alter (1) existing landscape character, whether foreground, intermediate ground, or background, and would be visible from viewpoints the National Park Service has established as important; (2) access to historically important viewpoints or sequence of viewpoints; or (3) the visibility of a viewpoint or sequence of viewpoints.

Duration of Impact

The duration of the impacts considers whether the impact would be short-term or long-term. A short-term impact would be short-lived or temporary due to construction, restoration, or demolition activities, and a long-term impact would be permanent and continual.

Intensity of Impact

The magnitude of impacts to the scenery within the view from specific vantage points and to specific scenic features is described as negligible, minor, moderate, or major as described below.

• Negligible impacts would be imperceptible or not detectable.

• Minor impacts would be slightly detectable or localized within a relatively small area.

• Moderate impacts would be those that are readily apparent.

• Major impacts would be substantial, highly noticeable, and/or result in changing the character of the landscape.

Type of Impact

Impacts were evaluated in terms of whether they would be beneficial or adverse to scenic resources. Beneficial impacts would enhance the existing landscape character, access to historically important viewpoints or sequence of viewpoints, or the visibility of a viewpoint or sequence of viewpoints. Adverse impacts would be effects that reduce the existing landscape character, access to historically important viewpoints or sequence of viewpoints, or the visibility of a viewpoint or sequence of viewpoints.

Visitor Experience and Recreation

Impacts on visitor experience and recreation may occur as a result of changes to road circulation, interpretation facilities, campgrounds and lodging, trails, and other facilities and resources that contribute to the type and quality of the visit to Yosemite National Park. They may also occur from direct actions altering the availability of a specific experience or activity.

Visitor experience and recreation are also directly affected by actions influencing natural resources such as air quality, scenic resources, and cultural resources. Though impacts to these resources are not repeated in the analysis of visitor experience, enhancement or degradation of these resources also enhances or degrades the quality of the visitor experience.

Impacts on visitor experience and recreation have been assessed using professional judgment to develop a qualitative analysis of the effects of actions on the activities of different visitor populations. These conclusions have been considered in combination with data on the proportion, when known, of visitors who participate in different activities while in the park.

Exterior lighting of certain construction sites may be needed for implementation of some alternatives. This lighting has the potential to affect the ability to see the night sky and landscape. Potential impacts on the night sky (ability to see stars and the effect of the sky on the landscape) have been identified for construction activities for each alternative.

Assumptions used in evaluating visitor experience impacts for the alternatives include the following:

• Existing facilities have come into being in response to visitor demands and needs. This includes roads, trails, turnouts and viewpoints, and various visitor services and accommodations.

• Visitors typically prefer to use private vehicles for travel to the park.

• Anticipated changes in visitor participation would represent an effect.

• Anticipated changes in trip quality would represent an effect.

• Anticipated changes in service level (such as reductions in accommodations or increase in services) would represent an effect.

Duration of Impact

A short-term impact on visitor experiences would be temporary in duration due to construction, restoration, or demolition activities. A long-term impact would have a permanent effect on the visitor experience.

Intensity of Impact

The intensity of impacts has been defined as negligible, minor, moderate, and major. Negligible impacts would result in little noticeable change in visitor experience. Minor impacts would result in changes in desired experiences but without appreciably limiting or enhancing critical characteristics. (Critical characteristics are those elements of a recreational activity that are most important to those who pursue it; for example, it may be important to picnickers to be able to drive to a picnic site.) Moderate impacts would change the desired experience appreciably, (i.e., changes one or more critical characteristics, or appreciably reduces/increases number of participants). Major impacts would eliminate or greatly enhance multiple critical characteristics or greatly reduce/increase participation.

Type of Impact

Impacts were evaluated in terms of whether they would be beneficial or adverse to visitor experience. Beneficial impacts would enhance visitor participation, quality of visitor experience, and service level. Adverse impacts would be effects that reduce visitor participation, quality of visitor experience, and service level.

Park Operations and Facilities

Transportation

The focus of this impact assessment was on the effect of changes to access, traffic volumes/circulation, and associated traffic flow and safety conditions. Because proposed utility infrastructure improvements would occur throughout the Valley and would often be coordinated with other construction projects undertaken over the next several years, this project does not lend itself to quantification of traffic impacts. Professional transportation planning 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 alternatives to reduce the intensity of adverse effects.

Duration of Impact

A short-term impact is one that would be created during construction activities (e.g., temporary disruption of access during construction of utility improvements). A long-term impact would be created through a permanent change to traffic generation or traffic circulation patterns following completion of the construction phase of the alternative action.

Intensity of Impact

The intensity of impact is classified as either negligible, minor, moderate, or major. Negligible impacts are effects considered not detectable and would have no discernible effect on traffic flow and/or traffic safety conditions. Minor impacts are 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.

Type of Impact

Impacts are considered in the context of being either beneficial or adverse on 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.

Park Operations

Impacts for each project alternative were evaluated by assessing changes to operations that would be required to meet various operational requirements outlined in each of the project alternatives. A qualitative assessment of relative costs was prepared using staff estimates of the funding and labor required to implement these actions. These effects were compared to existing operations, staffing, and funding, which are described in Chapter III.

Existing staffing levels were inventoried and assessments were made of current park operations. In addition, professional judgments by individuals who are most knowledgeable about various activities were used to anticipate the operational changes that would be needed under each action alternative. Estimates were made of the personnel required to maintain Valley utility infrastructure under each of the alternatives. It should be noted that in many cases, existing staffing levels are lower than knowledgeable staff believe necessary to support current operations. It should also be noted that staffing and funding impacts for the action alternatives are difficult to project until such time as final facility designs and operational planning are available. Thus, the estimates are intended to provide a general description of potential effects, considering the variability within the range of possible operational scenarios.

The discussions of impacts are for those operations that would be new, undergo major operational change, or show susceptibility to increases or decreases in operational activity. For example, a decrease in the miles of lines of utilities might reduce staffing needs for facilities management or an increase in the number of lift stations may increase staffing needs and operations costs.

Duration of Impact

Short-term impacts would last only until all construction actions associated with implementation of an alternative are completed. Long-term impacts typically last 10 years or more and would have a permanent effect on operations.

Intensity of Impact

With negligible impacts, there would not be a measurable difference in costs from existing levels. With minor impacts, measurable additions or reductions in cost would be less than 15% of existing levels. With moderate impacts, additions or reductions in cost would be between 15% and 30% of existing levels. With major impacts, additions or reductions in cost would exceed 30% of existing levels.

Type of Impact

Adverse impacts represent an increase in operating costs. Beneficial impacts represent a decrease in operating costs.

Social and Economic Environment

Analysis of social and economic impacts has been included to evaluate potential effects of the alternatives on the region’s economies. The region in this case consists of Madera, Mariposa, and Tuolumne Counties. Environmental consequences of implementing the alternatives were evaluated primarily based on expenditures and the percentage of these expenditures that would occur within the region. The socioeconomic analysis takes into account direct and secondary project-related spending effects. Direct effects are representative of the immediate spending within the sector of the economy where the initial stimulus occurs. Secondary effects include both induced and indirect effects. Induced effects are the impacts resulting from the initial stimulus on the economy from changes in personal consumption (resulting from changes in employee income). Indirect effects represent the impact of the initial stimulus on the economy resulting from changes in business spending. The combination of both direct and secondary spending effects results in the total for project-related spending. The secondary and indirect effects of construction spending within the region are estimated based upon Regional Input-Output Modeling System (RIMS) economic multipliers for California, developed by the U.S. Department of Commerce, Bureau of Economic Analysis, as reported by the State of California (CTTCA 2002).

Potential impacts were evaluated using professional judgment to ascertain reasonable conclusions in the areas of context, duration, intensity and type of the potential impacts.

Duration of Impact

The analysis considered an assessment of duration and distinguished between short-term and long-term duration to understand the extent of the identified effects. In general, short-term impacts are temporary in duration and typically are transitional effects associated with implementation of an action (e.g., related to construction activities). In contrast, long-term impacts have a permanent effect on the social and economic environments (e.g., operational activities).

Intensity of Impact

The intensity of each impact was rated in terms of increasing severity, as negligible, minor, moderate, or major. Negligible impacts are effects considered not detectable and are expected to have no discernible effect on the social and economic environment. Minor impacts are slightly detectable and are not expected to have an overall effect on the character of the social and economic environment. Moderate impacts are detectable, without question, and could have an appreciable effect on the social and economic environment. Such impacts would have the potential to initiate an increasing influence on the social and economic environment (particularly if other factors have a contributing effect). Major impacts are considered to have a substantial, highly noticeable influence on the social and economic environments, and could be expected to alter those environments permanently.

Type of Impact

Impacts were recognized as beneficial if they would improve upon characteristics of the existing social and economic environment, as it relates to visitor population and regional economies. Conversely, impacts were considered adverse if they would degrade or otherwise negatively alter the characteristics of the existing environment.

Alternative 1: No Action

Alternative 1, the No Action Alternative, would maintain the existing utility infrastructure in the east Valley, including necessary repairs and maintenance of the utility systems. It provides a baseline from which to compare the action alternatives, to evaluate the magnitude of proposed changes, and to measure the environmental effects of those changes.

Under the No Action Alternative, no management action would be taken to implement an East Yosemite Valley Utilities Improvement Plan. The existing dispersed utility lines would remain in place, including those utility lines located within meadows identified for ecological restoration in the Yosemite Valley Plan and other environmentally and culturally sensitive areas. Utility corridors would not be established to consolidate multiple utilities into corridors designed to follow existing utility or transportation corridors or proposed transportation corridors and to minimize potential impacts on environmentally sensitive areas. Efficient utility services would not be provided to new facilities proposed under the Yosemite Valley Plan.

The No Action Alternative would include those utility infrastructure projects currently planned for the wastewater collection system and required by the California Regional Water Quality Control Board to address recent wastewater releases. These projects are required to continue the current management and operation of the existing Yosemite Valley wastewater system.

Natural Resources

Soils

Analysis

Soils in Yosemite Valley include resilient, highly valued, and other soils as described in Chapter III, Affected Environment. Soil impacts associated with construction activities include changes to the soil profile and structural characteristics as well as soil compaction related to the use of heavy equipment. Removal of vegetation in construction areas can also result in accelerated soil erosion, particularly near watercourses. Finally, construction activities have the potential to result in incidental spills of hydrocarbons or other substances impacting micro- or macro-organisms present in the soils.

Impacts to soils associated with Alternative 1 are summarized in table IV-3 and described by subarea below.

Happy Isles. Required repairs would result in the disturbance of approximately 0.6 acre of soils that are classified as neither highly valued nor resilient soils. Soil excavation would result in disruption of the existing soil profile, interrupting the natural chemical, physical, and biological process in the soil. However, it is likely that soils in this area have previously been disturbed through construction of the utilities that are to be repaired. The localized removal of vegetation and use of heavy equipment would increase soil erosion and result in soil compaction in these areas. In addition to the short-term construction impacts, continued operation and maintenance of the utilities is expected to have localized, long-term, minor, adverse indirect effects on soils from continued disruption of natural subsurface water flows and resulting effects to soil characteristics.

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Table IV-3

Soil Impacts Associated with Alternative 1
 

The areas that would be affected are within an existing utility corridor that has been previously disturbed by utility installation and maintenance. Construction impacts would be mitigated through minimizing the area disturbed, salvaging the existing soils for use as backfill, implementing Best Management Practices during construction to reduce soil erosion and transport, and restoring the area with native plants when construction is complete.

Campgrounds. Construction activities in this area would include spot repairs to the existing wastewater lines serving the Upper Pines and North Pines Campgrounds. In addition, the existing wastewater line that crosses Tenaya Creek to the north from North Pines Campground must be excavated and replaced. Construction activities associated with these repairs would result in the disturbance of up to 2.2 acres of soils. Of these soils, approximately 1 acre is classified as highly valued, 0.9 acre is classified as resilient, and 0.3 acre is classified as other. Impacts to soils would be similar to those described above for the Happy Isles area but would also include an increased risk of soil erosion and transport due to excavation of the riverbanks and bed.

The areas that would be affected are within existing utility corridors that have been previously disturbed and are currently developed as campground areas. Construction impacts would be mitigated as discussed above for the Happy Isles area, with particular attention to erosion control measures and bank stabilization during construction work within Tenaya Creek.

Ecological Restoration Area. Construction activities in this area would include significant replacements and spot repairs to existing wastewater lines. Repairs needed include replacement of the wastewater utility line river crossing from Lower Pines Campground to North Pines Campground and replacement of the wastewater utility line river crossing just east of Stoneman Bridge. The wastewater line repairs would result in disturbance of up to 5.3 acres of soil, including approximately 4.6 acres of highly valued soils, 0.4 acre of resilient soils, and 0.3 acre of soils classified as other. Soil excavation would result in impacts as described above for the Happy Isles area.

The areas that would be affected are within existing corridors that have been previously disturbed and developed as campgrounds, but which are currently identified for ecological restoration in the Yosemite Valley Plan. Construction impacts would be mitigated as described above for the Happy Isles area.

The Ahwahnee. Repairs to the wastewater utility infrastructure in The Ahwahnee area would result in the disturbance of up to 3.6 acres of soils, including approximately 1.8 acres of highly valued soils, 1.5 acres of resilient soils, and 0.3 acre of other soils. Impacts in construction areas are expected to be similar to those described above for the Happy Isles area.

The areas that would be affected are within existing corridors that have been previously disturbed and developed. Construction impacts would be mitigated through mitigation measures as discussed above for the Happy Isles area.

Curry Village. The wastewater utility infrastructure in the Curry Village area also requires significant replacement and repairs of the existing system. Construction activities are expected to disturb up to 2 acres of soil, including approximately 1.2 acres of resilient soils and 0.8 acre of other soils. Impacts in construction areas are expected to be similar to those described above for the Happy Isles area.

The areas that would be affected are within existing corridors that have been previously disturbed and developed, and are currently proposed for redevelopment. Construction impacts would be mitigated as described above for the Happy Isles area.

Housekeeping Camp. Repairs to the wastewater utility infrastructure in the Housekeeping Camp area would result in the disturbance of up to 2.5 acres of soil, including approximately 2.2 acres of highly valued soils and 0.3 acre of resilient soils. Impacts in construction areas are expected to be similar to those described above for the Happy Isles area.

The areas that would be affected are within existing corridors that have been previously disturbed and developed. Construction impacts would be mitigated through mitigation measures as discussed above for the Happy Isles area.

Yosemite Village. Repairs to the wastewater utility infrastructure in Yosemite Village would result in disturbance of up to 8.7 acres of soils, including approximately 0.5 acre of highly valued soils, 6.5 acres of resilient soils, and 1.7 acres of other soils. Impacts in construction areas are expected to be similar to those described above.

The areas that would be affected are within existing corridors that have been previously disturbed and developed. Construction impacts would be mitigated through mitigation measures as discussed above.

Camp 6/Cook’s Meadow. Repairs to the wastewater utility infrastructure in the Camp 6 area would result in disturbance of up to 6.1 acres of soils, approximately 4.2 acres of highly valued soils, 0.9 acre of resilient soils, and 1 acre of soils classified as other. Repairs in this area include the excavation and replacement of the Yosemite Creek utility line crossing. Impacts in construction areas are expected to be similar to those described above.

The areas that would be affected are within existing corridors that have been previously disturbed and developed. Construction impacts would be mitigated through mitigation measures as discussed above.

Summary of Alternative 1 Impacts

According to the Yosemite Valley Plan (NPS 2000a), approximately 407 acres of soil in the Valley are currently affected by some level of previous disturbance. Of this acreage, 120 acres are highly valued resource soils, 217 acres are resilient soils, and the remaining soils are classified as other. All of the utility repairs proposed in this alternative would occur in areas previously disturbed by utility construction and maintenance. Repair activities required to maintain the existing wastewater lines would impact approximately 31 acres of soils, of which approximately 14 acres are classified as highly valued, 12 acres are classified as resilient, and 5 acres are classified as other.

This alternative is expected to have a local, short-term, moderate, adverse effect on highly valued soils; a local, short-term, minor, adverse effect on resilient soils; and a local, short-term, negligible, adverse effect on other soils from construction activities. Construction impacts to soils would be mitigated by implementation of Best Management Practices to minimize spills, soil compaction, and erosion. Implementation of these mitigation measures would be expected to reduce soil impacts to a minor intensity. In addition, there would continue to be local, long-term, minor, adverse indirect effects on soils from ongoing disruptions of natural subsurface flows and resultant effects on soil characteristics over time.

Cumulative Impacts

Cumulative impacts to soil resources are based on analysis of past, present, and reasonably foreseeable future actions in Yosemite Valley in combination with potential effects of this alternative. The projects identified below include only those projects that could affect soil resources within Yosemite Valley.

Certain development projects could result in increased degradation of soil resources, such as expansion of campgrounds and construction of lodging and employee housing in Yosemite Valley, as identified in the Yosemite Valley Plan. However, other Yosemite Valley Plan projects related to habitat restoration (such as removal of roads through Stoneman and Ahwahnee Meadows, and the Ecological Restoration of Flood-Damaged Campgrounds) designed to restore wet meadow habitats in areas previously developed as campgrounds would have long-term, beneficial effects on soils. Although these types of projects may have slight site-specific, short-term, adverse effects (e.g., potential construction erosion and soil loss), the objective of these projects is to restore and manage natural resources and reduce soil degradation. For example, full implementation of the Yosemite Valley Plan would restore approximately 177 acres of soil, of which approximately 136 acres would be highly valued resource soils in Yosemite Valley. The cumulative projects would result in local, long-term, minor, beneficial cumulative impacts to soil resources. Alternative 1 could minimize these benefits because utilities would remain in the areas proposed for ecological restoration, thus requiring future utility repairs and continuing to disrupt natural subsurface water flows. This would result in minor, long-term, localized adverse impacts to soil resources.

Alternative 1 and the cumulative projects would have a local, long-term, negligible to minor, beneficial impact to soils from ecological restoration with existing utilities left in place.

Impairment

Alternative 1 would continue maintenance of existing utility infrastructure within existing disturbed areas and would not be expected to impair the park’s soil resources.

Hydrology, Floodplains, and Water Quality

Analysis

Under Alternative 1, the existing utility infrastructure would remain in place, including the existing 13 individual utility line crossings of the Merced River and major tributaries. Although the design and underground location of these utilities minimizes impacts from many hazards, natural processes, such as riverbank scouring, can expose or damage utilities over time. Existing utility line crossings that have been exposed would continue to adversely influence the free flow of the river by altering flow dynamics and could result in localized morphologic changes to the bed and banks of the river until repairs are undertaken to excavate and replace the utility crossing at a lower elevation. The high number of utility line river crossings results in a high potential for facilities to be damaged during flood events, with the potential for water quality impacts from wastewater releases. Alternative 1 would leave utility infrastructure concentrated in the floodplain and River Protection Overlay area (see discussion of River Protection Overlay in Chapter V, Merced Wild and Scenic River). Ongoing maintenance and repairs of these facilities would continue to result in hydrologic impacts to natural subsurface flows between meadows and the river and water quality impacts associated with repair and maintenance construction activities in the riverbed and banks.

Impacts on hydrology, water quality, and the floodplain associated with Alternative 1 are described by subarea below.

Happy Isles. Repairs proposed in the Happy Isles area would result in the temporary loss of vegetation and have the potential for increased soil erosion and associated water quality impacts. The use of heavy equipment presents a potential for accidental releases of fuels or other hazardous substances that could impact local surface water or groundwater quality.

Construction impacts would be mitigated through minimizing the area disturbed, salvaging the existing soils for use as fill, and implementing Best Management Practices during construction to reduce the potential for water quality impacts associated with soil erosion and construction equipment releases. Restoration of the pre-existing grade and revegetation upon project completion is expected to reduce the short-term adverse impacts to local hydrologic processes and water quality to a minor level.

A small portion of this area is located within the floodplain, where some repairs would occur. Alternative 1 would not increase facilities in the floodplain but only maintain the existing system and so would not affect the floodplain’s current ability to accommodate flood flows.

Campgrounds. Construction activities in the Campgrounds area would include excavation and replacement of the wastewater line that crosses from North Pines Campground to the north across Tenaya Creek. Reconstruction of this line would result in local, short-term, moderate adverse effects to creek flow and water quality associated with the temporary diversion of water and increased sediment transport that would occur during construction and the excavation of the creekbank and creekbed for replacement of the utility line. The use of heavy equipment in the creek could result in accidental releases of fuels or other hazardous substances impacting water quality. Retention of the wastewater line crossing the creek would continue the potential for long-term, local, adverse water quality impacts associated with wastewater releases into the creek and ongoing repairs and maintenance within the creekbed and banks.

Construction impacts would be minimized by constructing the creek crossing during seasonal low water, thus minimizing the disturbance area on the bank and creekbed, salvaging creekbed materials for replacement after construction, returning the creekbed to its pre-existing contour, and implementing Best Management Practices during construction. These measures would be expected to reduce short-term adverse effects to a minor to moderate level.

Although some of the repairs in the Campgrounds area would occur within the floodplain, Alternative 1 would not change the existing concentration of utility facilities within the floodplain or its ability to accommodate water flows during floods.

Ecological Restoration Area. In addition to utility line repairs within the Ecological Restoration area, the Merced River wastewater line crossing from Lower Pines to North Pines Campgrounds would be excavated and replaced. Reconstruction of this line would result in local, short-term, moderate adverse effects to river flow and water quality associated with the temporary diversion of water required during construction and the excavation of the riverbank and riverbed for replacement of the utility line. The use of heavy equipment in the river could result in accidental releases of fuels or other hazardous substances impacting water quality.

Retention of the wastewater line crossing the river would continue the potential for adverse water quality impacts associated with wastewater releases into the river. Retaining utility infrastructure in the environmentally sensitive and wetland areas identified for ecological restoration under the Yosemite Valley Plan would also adversely affect the hydrology of the area by impeding the natural subsurface water flows between the river and adjacent meadow areas, resulting in a localized, long-term, minor, adverse effect.

Construction impacts related to utility repairs would be minimized by constructing the river crossing during seasonal low water, minimizing the disturbance area on the riverbank and riverbed, salvaging riverbed materials for replacement after construction, and returning the riverbed to its pre-existing elevation and contour. Use of Best Management Practices during construction can minimize the potential for water quality impacts associated with accidental spills or soil erosion. With mitigation, the construction related effects on hydrology and water quality are expected to be reduced to a minor to moderate intensity.

Repair activities in the Ecological Restoration area all would occur within the floodplain. Although the repairs in this area would occur within the floodplain, Alternative 1 would not change the existing concentration of utility facilities within the floodplain or its ability to accommodate flood flows.

The Ahwahnee. Construction impacts to hydrology, floodplains, and water quality in The Ahwahnee area would be similar to those discussed for the Happy Isles area above. Hydrology and water quality impacts would also be mitigated as described for the Happy Isles area. Retaining utility infrastructure in Ahwahnee Meadow could continue existing local, long-term, minor, adverse effects on subsurface water flow through the meadow.

Although some of the repairs in The Awahnee area would occur within the floodplain, the existing concentration of utility facilities within the floodplain would not change, nor would the floodplain’s ability to accommodate flood flows.

Curry Village. The utility repairs in the Curry Village area would occur outside of the floodplain. Impacts to water quality and hydrology in construction areas are expected to be similar to those described above for the Happy Isles area.

The areas that would be affected are within existing corridors that have been previously disturbed and developed and which are currently proposed for redevelopment. Construction impacts would be mitigated as described for the Happy Isles area.

Housekeeping Camp. Repairs to the utility infrastructure in the Housekeeping Camp area would occur within the floodplain and include the replacement of a Merced River utility line crossing from Housekeeping Camp to the former Lower River Campground. Impacts in this area would be similar to those described above for the Merced River crossing in the Ecological Restoration area.

Construction impacts would be mitigated as discussed above for the Ecological Restoration area. Although Alternative 1 proposes repairs of utilities within the floodplain, it does not change the existing concentration of facilities in that area or the ability to accommodate flood flows.

Yosemite Village. Utility line repairs in the Yosemite Village area would occur outside of the floodplain. Construction impacts to water quality would be similar to those discussed above for the Happy Isles area. Construction impacts would be minimized as discussed above for the Happy Isles area.

Camp 6/Cook’s Meadow. Utility repairs in the Camp 6 area would occur within the floodplain and require construction in Yosemite Creek. Impacts from construction activities in Yosemite Creek would be similar to those discussed for the Merced River crossing in the Ecological Restoration area above, including local, short-term, moderate adverse effects to creek flow and water quality associated with the temporary diversion of water that would occur during construction and the excavation of the creekbank and creekbed for replacement of the utility line. The use of heavy equipment in the creek could result in accidental releases of fuels or other hazardous substances. Retaining utility infrastructure in Cook’s Meadow would continue existing local, long-term, minor, adverse hydrological impacts to the subsurface movement of water through the meadow.

Construction impacts would be mitigated as discussed above for the Ecological Restoration area and would be expected to reduce short-term construction effects to a minor level.

Although the repairs in this area would occur within the floodplain, the existing concentration of utility facilities within the floodplain and its ability to accommodate flood flows would not change under this alternative.

Summary of Alternative 1 Impacts

Alternative 1 proposes the ongoing maintenance and operation of existing utilities. Many of these utilities are currently located within the floodplain and several utility lines cross the Merced River or major tributaries. With the mitigation measures described in Chapter II and above, construction of required repairs is expected to result in short-term, minor, adverse effects on subsurface and surface water hydrology, and water quality within Yosemite Valley. This alternative would have local, long-term, minor, adverse effects on the free flow of the Merced River from the continuing future repairs to multiple utility line crossings that become exposed in the riverbed over time. Local, long-term, minor, adverse effects to subsurface water flows through meadow areas and between the river and adjacent meadows would continue with maintenance of current utility infrastructure. Maintenance of existing utilities within the floodplain would not affect the ability to accommodate flood flows.

Cumulative Impacts

Cumulative effects to hydrology, floodplains, and water quality are based on analysis of past, present, and reasonably foreseeable future actions in Yosemite Valley in combination with potential effects of Alternative 1.

The Merced River has been affected by a variety of projects over time 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 actions that have had adverse effects on the hydrologic processes of the Merced River include placement of riprap; removal of large woody debris; and construction of bridges, dikes, flood walls, impoundments, dams, and buildings. Conversely, more recent actions such as riverbank restoration projects, removal of impoundments and bridges, and limiting visitor use to particular areas help restore the natural river flow and reduce bank erosion.

Reasonably foreseeable future projects that would have beneficial impacts on hydrologic processes and water quality include restoration actions identified in the Yosemite Valley Plan. Elements of the Yosemite Valley Plan include removal of Sugar Pine Bridge, which constrains flows of the Merced River; rehabilitation of the Lower Yosemite Fall corridor; restoration of campgrounds within the floodplain to natural meadow conditions; and removal of facilities from the 100-year floodplain. Alternatively, construction of additional lodging, campsites, and a visitor transit center in the Valley could have adverse impacts on hydrology, floodplains, and water quality. Overall, the effect of implementation of projects identified in the Yosemite Valley Plan would have a long-term, beneficial effect on river hydrologic processes, floodplains, and water quality.

The Merced River Plan protects river-related natural resources through the application of management elements, including the River Protection Overlay, management zoning, protection and enhancement of Outstandingly Remarkable Values, Section 7 determination process, and implementation of a Visitor Experience Resource Protection framework (see Chapter V, Merced Wild and Scenic River).

Other proposed future projects include the Lower Yosemite Fall Project, Cascades Dam Removal, Happy Isles Dam Removal, Happy Isles to Vernal Falls Trail Reconstruction, and the Eagle Creek Merced River Ecological Restoration (Yosemite Valley). Cumulatively, these projects are anticipated to have beneficial impacts on hydrologic processes and water quality of the Merced River.

While some of the past, present, and reasonably foreseeable future projects along the Merced River in Yosemite Valley would ultimately remove constrictions to streamflows, enhance water quality, rehabilitate eroded streambanks, and reduce degradation of stream characteristics in the Merced River, others would result in adverse water quality impacts and bank erosion. Thus, the cumulative projects would result in a local, long-term, minor, beneficial impact to hydrologic processes and water quality. Alternative 1 would reduce this beneficial impact to some degree by retaining existing utility infrastructure within the floodplains and riverbanks, resulting in the potential for long-term, minor to moderate, adverse effects related to utility maintenance and repairs.

The past, present, and future projects in Yosemite Valley, considered cumulatively with Alternative 1, would have a local, long-term, negligible to minor, beneficial effect on hydrologic processes, floodplains, and water quality in Yosemite Valley.

Impairment

Impacts to hydrology, floodplains, and water quality associated with Alternative 1 are expected to be minor and localized. Alternative 1 would not impair the hydrologic resources of the park for future generations.

Wetlands

Analysis

Alternative 1 would continue the maintenance and operation of existing utility infrastructure in Yosemite Valley, including those utility lines through wetland areas. Direct and indirect impacts to wetland and aquatic habitats could occur as a result of normal maintenance and repair of the utility lines over time, as well as from known required wastewater system repair projects. Repair activities may impact wetland and aquatic habitats directly due to soil disturbance during excavation; soil compaction related to the use of heavy equipment; vegetation removal, which can also result in accelerated soil erosion; root damage; and introduction and spread of non-native species. Wetland and aquatic habitats in the vicinity of repair activities may be indirectly impacted by the addition of silt, the resuspension of sediment, or the introduction of pollutants (i.e., fuels or lubricants) related to construction activities. Alternative 1 would leave utility infrastructure concentrated in the floodplain and River Protection Overlay area (see discussion of River Protection Overlay in Chapter V, Merced Wild and Scenic River). Ongoing maintenance and repairs of these facilities would continue to result in long-term impacts to natural subsurface flows between the river and adjacent wetland areas.

The Cowardin system of wetland classification was used for the impact analysis, as it protects a broader range of wetlands than those classified as jurisdictional under the U.S. Army Corps of Engineers. Wetland and aquatic habitats in Yosemite Valley include riverine upper perennial, palustrine forest, palustrine scrub shrub, and palustrine emergent as described in Chapter III, Affected Environment. Impacts associated with Alternative 1 are described by subarea below. Table IV-4 provides the acreage by subarea of wetland and aquatic habitats potentially affected by Alternative 1.

Happy Isles. In the Happy Isles area, there are no wetland or aquatic habitats present within the areas to be affected by repair activities. Therefore, direct impacts to wetland or aquatic habitats are not anticipated; however, indirect impacts to wetland or aquatic habitats in the immediate vicinity of the repairs (e.g., the Merced River) may include the addition of silt and the introduction of pollutants (i.e., fuels or lubricants). The application of mitigation measures described in Chapter II, specifically those related to stormwater management measures and spill prevention and pollutant control, would reduce the potential localized, short-term, adverse, construction-related impacts to wetland and aquatic habitats in the Happy Isles area to a negligible intensity.

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Table IV-4

Wetland and Aquatic Habitats Potentially Affected by Alternative 1
 

Campgrounds. There would be no permanent reduction in the size of wetland and aquatic habitats in the Campgrounds area. There would be localized, short-term, adverse, construction-related impacts to 0.30 acre of wetland and aquatic habitats, which include riverine upper perennial, palustrine forest, palustrine scrub shrub, and palustrine emergent. Effects to wetland and aquatic habitats would be related to heavy equipment and repair activities and could include soil disturbance and compaction, dust, vegetation removal, root damage, erosion, and introduction and spread of non-native species. The addition of silt, the resuspension of sediment, or the introduction of pollutants (i.e., fuels or lubricants) related to construction activities could degrade the quality of native wetland and aquatic habitats in the immediate vicinity of the repairs. The application of mitigation measures described in Chapter II, specifically those related to protection of wetland areas, minimization of disturbance areas, stormwater management measures, and spill prevention and pollutant control, would reduce the potential local, short-term, adverse impacts to wetland and aquatic habitats to a minor intensity. In addition, with the application of the mitigation measures, there would be no long-term impacts associated with Alternative 1 on the integrity and connectivity of the wetlands. However, the continued presence of utility infrastructure within wetland and aquatic habitats could have local, long-term, minor, adverse effects on the hydrology of these habitats by impeding the natural subsurface water flows within wetland areas and between the river and adjacent wetlands.

Ecological Restoration Area. There would be no permanent reduction in the size of wetland and aquatic habitats in the Ecological Restoration area. There would be localized, short-term, adverse, construction-related impacts to 0.83 acre of wetland and aquatic habitats, which include riverine upper perennial and palustrine emergent. Effects to wetland and aquatic habitats related to repair activities would be similar to those discussed for the Campgrounds area. The application of mitigation measures discussed above for the Campgrounds area would reduce the potential local, short-term, adverse construction-related impacts to wetland and aquatic habitats to a minor intensity. However, retaining utility infrastructure in wetland areas could result in local, long-term, minor, adverse effects to wetlands due to their obstruction of natural subsurface water flows within wetland habitats and between the river and adjacent wetland areas.

The Ahwahnee. There would be no permanent reduction in the size of wetland and aquatic habitats in the Ahwahnee area. There would be localized, short-term, adverse, construction-related impacts to 1.55 acres of palustrine emergent wetland habitat. Effects to wetland and aquatic habitats related to repair activities would be similar to those discussed for the Campgrounds area. The application of mitigation measures discussed above for the Campgrounds area would reduce the potential local, short-term, adverse construction-related impacts to wetland and aquatic habitats to a minor intensity.

Curry Village. There would be no permanent reduction in the size of wetland and aquatic habitats in the Curry Village area. There would be localized, short-term, adverse, construction-related impacts to 0.06 acre of wetland habitat, which includes palustrine forest and palustrine emergent. Effects to wetland and aquatic habitats related to repair activities would be similar to those discussed in the Campgrounds area. The application of mitigation measures as described above for the Campgrounds area would reduce the potential local, short-term, adverse impacts to wetland and aquatic habitats to a negligible intensity.

Housekeeping Camp. There would be no permanent reduction in the size of wetland and aquatic habitats in the Housekeeping Camp area. There would be localized, short-term, adverse, construction-related impacts to 0.19 acre of riverine upper perennial habitat. Effects to wetland and aquatic habitats related to repair activities would be similar to those discussed above for the Campgrounds area. The application of mitigation measures as discussed for the Campgrounds above would reduce the potential adverse impacts to wetland and aquatic habitats to a negligible intensity.

Yosemite Village. There would be no permanent reduction in the size of wetland and aquatic habitats in the Yosemite Village area. There would be localized, short-term, adverse, construction-related impacts to 0.13 acre of palustrine emergent wetland habitat. Effects to wetland and aquatic habitats related to repair activities would be similar to those discussed for the Campgrounds area. The application of mitigation measures discussed above for the Campgrounds area would reduce the potential local, short-term, adverse construction-related impacts to wetland and aquatic habitats to a negligible intensity.

Camp 6/Cook’s Meadow. There would be no permanent reduction in the size of wetland and aquatic habitats in the Camp 6/Cook’s Meadow area. There would be localized, short-term, adverse, construction-related impacts to 0.76 acre of wetland and aquatic habitats, which include riverine upper perennial, palustrine forest, and palustrine emergent. Effects to wetland and aquatic habitats related to repair activities would be similar to those discussed for the Campgrounds area. The application of mitigation measures discussed above for the Campgrounds area would reduce the potential adverse impacts to wetland and aquatic habitats to a minor intensity.

Summary of Alternative 1 Impacts

There would be no permanent reduction in the size of wetland and aquatic habitats in Yosemite Valley associated with Alternative 1. There would be localized, short-term, adverse, construction-related impacts to 3.82 acres of wetland and aquatic habitats, which corresponds to approximately 0.4 % of the wetland and aquatic habitats within Yosemite Valley. The areas that would be affected are within existing corridors that have previously been disturbed and developed. Impacts to wetland and aquatic habitats in these areas are not expected to have long-term, adverse effects on the size, integrity, and connectivity of wetlands in Yosemite Valley. Wetland impacts associated with Alternative 1 are expected to be localized, short-term, minor, adverse, construction-related impacts.

Construction impacts would be mitigated through the application of mitigation measures described in Chapter II, specifically those related to protection of wetland areas, minimization of disturbance areas, stormwater management measures, and spill prevention and pollutant control. However, the continued presence of utility infrastructure within wetland and aquatic habitats would continue to have long-term, minor, adverse effects on the hydrology of these habitats by impeding the natural subsurface water flows within wetland areas and between the river and adjacent wetlands.

Cumulative Impacts

Cumulative effects to wetland and aquatic resources are based on analysis of past, present, and reasonably foreseeable future actions in Yosemite Valley in combination with potential effects of this alternative. The projects identified below include those projects that have the potential to affect local wetland patterns.

Wetland and riparian systems of the Merced River corridor have been substantially altered by development and visitor activities. These changes have negatively influenced the size, form, and function of wetlands 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 would include wetland restoration, rehabilitation projects, and ecosystem management. Cumulative adverse effects would be related to increased facilities, regional growth, and visitor demand.

Reasonably foreseeable future actions within Yosemite Valley are considered to have an overall beneficial effect on wetlands. For example, the Merced River Plan protects river-related natural resources through the application of management elements, including the River Protection Overlay, management zoning, protection and enhancement of Outstandingly Remarkable Values, and implementation of a Visitor Experience Resource Protection framework (refer to Chapter V, Merced Wild and Scenic River).

Full implementation of the Yosemite Valley Plan would result in a net gain of 118 acres of wetlands in Yosemite Valley through actions such as restoration of the former Upper and Lower River Campgrounds and a portion of Lower Pines Campground to natural conditions; removal of roads through Stoneman and Ahwahnee Meadows; and removal of other bridges (e.g., Sugar Pine and possibly Stoneman) affecting the natural flow of the Merced River. Alternative 1 could minimize these benefits because utilities would remain in the restoration areas and utility repairs needed in the future would continue to have short-term, localized, adverse impacts to these resources. Farther downstream, removal of the Cascades Diversion Dam would remove an unnatural constriction to the free flow of the Merced River, thereby enhancing natural river dynamics including wetlands and aquatic systems below Yosemite Valley. Some Yosemite Valley Plan projects, such as construction of a replacement footbridge at the Happy Isles area, construction of a vehicle bridge across Yosemite Creek near Yosemite Lodge, and expansion of some campgrounds in Yosemite Valley, have the potential to adversely affect local wetlands. These projects would be designed to ensure the long-term protection of wetlands consistent with the Merced River Plan, the Clean Water Act, and Executive Order 11990: Protection of Wetlands.

Cumulative actions would have a long-term, moderate, beneficial cumulative effect on wetlands within Yosemite Valley due to wetland restoration efforts. The local, short-term and long-term, minor, adverse effects from ongoing maintenance and repairs associated with Alternative 1 would somewhat reduce the beneficial effects of the cumulative projects resulting in long-term, minor to moderate, beneficial effects.

Impairment

The No Action Alternative would result in local, short and long-term, minor, adverse effects to wetland and aquatic habitats due to planned wastewater repair and maintenance activities. These short-term effects would not impair the park’s wetland resources for future generations.

Vegetation

Analysis

Alternative 1 would continue the maintenance and operation of the existing utility systems in Yosemite Valley. Required repairs identified for the existing system would occasionally result in some minor loss of vegetation in repair areas. Effects would be related to the use of heavy equipment for excavation and repair activities and could include soil disturbance and compaction, dust generation, vegetation removal, root damage, erosion, introduction and spread of non-native species, and spread of annosus root disease. The addition of pollutants (i.e., fuels or lubricants) related to utility repair operations could degrade the quality of native vegetation. In addition, there would continue to be a minor long-term loss of vegetation due to routine clearance of vegetation at utility access manholes may occur.

As discussed in Chapter III, annosus root disease is present in many areas of the Valley, including areas that would be impacted by proposed actions under this alternative. Most soils excavated under this project will be stored on site and reused as fill. Any soils that cannot be reused on site and must be moved off site would be treated in accordance with park root rot management policies to ensure that infected materials are not moved into other areas.

Impacts on vegetation associated with Alternative 1 are described by subarea below. Table IV-5 provides the acreage by subarea of vegetation community types potentially affected by Alternative 1. Meadow, riparian, and California black oak vegetation communities are identified as highly valued resources in the Yosemite Valley Plan.

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Table IV-5

Vegetation Community Types Potentially Affected by Alternative 1
 

Happy Isles. In the Happy Isles area, Alternative 1 would result in the disturbance and localized removal of vegetation over approximately 0.6 acre, which includes 0.1 acre of riparian, a highly valued resource. The vegetation or cover types that would be affected by the localized removal of vegetation include mixed riparian-conifer corridor forest, developed ponderosa pine forest, white fir-Douglas fir forest, and developed open area-sparse vegetation. Construction-related repairs planned in this area would have localized, short-term, adverse effects to vegetation. Effects would be related to heavy equipment and excavation and repair activities and could include soil disturbance and compaction, dust generation, vegetation removal, root damage, erosion, introduction and spread of non-native species, and spread of annosus root disease. The addition of pollutants (i.e., fuels or lubricants) related to utility repair operations could degrade the quality of native vegetation. Wastewater repairs required in this area would have local, short-term, minor, adverse effects to vegetation. In addition, localized, long-term, minor loss of vegetation due to routine clearance of vegetation at utility access manholes may occur.

The areas that would be affected are within an existing utility corridor that has been previously disturbed by utility installation and maintenance. The application of mitigation measures described in Chapter II, particularly those designed to address revegetation, minimization of disturbance areas, non-native species, and annosus root disease, would reduce the local, short-term, adverse construction-related impacts to vegetation to a negligible to minor intensity. With the application of the mitigation measures described in Chapter II, the geographic extent, continuity, integrity, and resilience of plant communities would not be permanently impacted by repair and maintenance activities associated with Alternative 1.

Campgrounds. In the Campgrounds area, Alternative 1 would result in the disturbance and localized removal of vegetation over approximately 2.2 acres, which includes 0.5 acre of riparian, a highly valued resource. California black oak, a highly valued resource, may also be adversely affected by construction activities when present within mixed conifer vegetation communities. The vegetation or cover types that would be affected by the localized removal of vegetation include fen, mixed riparian-conifer corridor forest, impacted mixed riparian-conifer corridor forest, open ponderosa pine-California black oak woodland, developed open ponderosa pine-California black oak woodland, developed ponderosa pine forest, sparse ponderosa pine scrub, and river. Planned repairs required in this area would have local, short-term, minor, adverse effects to vegetation. Effects to vegetation related to construction activities would be similar to those discussed for the Happy Isles area. In addition, localized, long-term, minor loss of vegetation due to routine clearance of vegetation at utility access manholes may occur.

The areas that would be affected are within an existing utility corridor that has been previously disturbed by utility installation and maintenance, as well as campground development and use. The application of mitigation measures as described above would reduce the local, short-term, adverse construction-related impacts to vegetation to a minor intensity.

Ecological Restoration Area. In the Ecological Restoration area, Alternative 1 would result in the disturbance and localized removal of vegetation over approximately 5.3 acres, which includes 1.0 acre of meadow and 0.1 acre of riparian, both highly valued resources. California black oak, a highly valued resource, may also be adversely affected by construction activities when present within mixed conifer vegetation communities. The vegetation or cover types that would be affected by the localized removal of vegetation include bunch-grass meadow, Carex vesicaria wet meadow, impacted mixed riparian-conifer corridor forest, developed open ponderosa pine-California black oak woodland, ponderosa pine forest, dense mixed coniferous forest, and river. Planned repairs to existing utilities in this area would have local, short-term, minor to moderate, adverse effects to vegetation. Localized, long-term, minor loss of vegetation due to routine clearance of vegetation at utility access manholes may occur. Effects to vegetation related to construction activities would be similar to those discussed for the Happy Isles area.

The areas that would be affected are within existing corridors that were previously disturbed and developed as campgrounds, but are currently identified for ecological restoration in the Yosemite Valley Plan. The application of mitigation measures described above for the Happy Isles area would reduce these potential local, short-term, adverse construction-related impacts to vegetation to a minor intensity. Maintenance of the existing utility infrastructure within these areas could result in local, long-term, minor, adverse effects to vegetation.

The Ahwahnee. In The Ahwahnee area, Alternative 1 would result in the disturbance and localized removal of vegetation over approximately 3.6 acres, which includes 1.6 acres of meadow and 0.2 acre of riparian, both highly valued resources. California black oak, a highly valued resource, may also be adversely affected by construction activities when present within mixed conifer vegetation communities. The vegetation or cover types that would be affected by the localized removal of vegetation include bunch-grass meadow, Carex senta wet meadow border, grass-sedge meadow, grass meadow, mixed low meadow, impacted mixed riparian-conifer corridor forest, open ponderosa pine-California black oak woodland, developed open ponderosa pine-California black oak woodland, ponderosa pine forest, developed ponderosa pine forest, sparse ponderosa pine scrub, dense mixed coniferous forest, river, watered lawn, and bare. Planned repairs in this area would have local, short-term, minor to moderate, adverse effects to vegetation. In addition, localized, long-term, minor loss of vegetation due to routine clearance of vegetation at utility access manholes may occur. Effects to vegetation related to construction activities would be similar to those discussed for the Happy Isles area.

The areas that would be affected are within existing corridors that have been previously disturbed and developed. The application of mitigation measures as discussed for the Happy Isles area above would reduce these potential local, short-term, adverse construction-related impacts to vegetation to a minor intensity.

Curry Village. In the Curry Village area, Alternative 1 would result in the disturbance and localized removal of vegetation over approximately 2.0 acres, which includes 0.1 acre of oak, a highly valued resource. The vegetation or cover types that would be affected by the localized removal of vegetation include grass-sedge meadow, California black oak woodland with encroaching conifers, ponderosa pine forest, developed ponderosa pine forest, dense mixed coniferous forest, developed open area-sparse vegetation, watered lawn, and bare. Construction-related repairs in this area would have local, short-term, minor, adverse effects to vegetation. In addition, localized, long-term, minor loss of vegetation due to routine clearance of vegetation at utility access manholes may occur. Effects to vegetation from construction activities would be similar to those discussed for the Happy Isles area.

The areas that would be affected are within existing corridors that have been previously disturbed and developed, and are currently proposed for redevelopment. The application of mitigation measures as discussed for the Happy Isles area above would reduce these potential local, short-term, adverse construction-related impacts to vegetation to a negligible to minor intensity.

Housekeeping Camp. In the Housekeeping Camp area, Alternative 1 would result in the disturbance and localized removal of vegetation over approximately 2.5 acres, which includes 0.1 acre of riparian, a highly valued resource. The vegetation or cover types that would be affected by the localized removal of vegetation include impacted mixed riparian-conifer corridor forest, developed open ponderosa pine-California black oak woodland, and river. Required construction-related repairs in this area would have local, short-term, minor, adverse effects to vegetation. In addition, localized, long-term, minor loss of vegetation due to routine clearance of vegetation at utility access manholes may occur. Effects to vegetation related to construction activities would be similar to those discussed for the Happy Isles area.

The areas that would be affected are within existing corridors that have been previously disturbed and developed. The application of mitigation measures discussed above for the Happy Isles area would reduce these potential local, short-term, adverse, construction-related impacts to vegetation to a negligible to minor intensity.

Yosemite Village. In the Yosemite Village area, Alternative 1 would result in the disturbance and localized removal of vegetation over approximately 8.7 acres, which includes 0.3 acre of meadow, 0.1 acre of riparian, and 3.5 acres of oak, all highly valued resources. The vegetation or cover types that would be affected by the localized removal of vegetation include grass-sedge meadow, grass meadow, white alder riparian forest, California black oak woodland, developed California black oak woodland, open ponderosa pine-California black oak woodland, developed open ponderosa pine-California black oak woodland, ponderosa pine forest, developed ponderosa pine forest, dense mixed coniferous forest, developed open area-sparse vegetation, and watered lawn. Proposed repairs in this area would have local, short-term, minor to moderate, adverse effects to vegetation. In addition, localized, long-term, minor loss of vegetation due to routine clearance of vegetation at utility access manholes may occur. Effects to vegetation related to construction activities would be similar to those discussed for the Happy Isles area.

The areas that would be affected are within existing corridors that have been previously disturbed and developed. The application of mitigation measures as discussed above for the Happy Isles area would reduce these potential local, short-term, adverse, construction-related impacts to vegetation to a minor intensity.

Camp 6/Cook’s Meadow. In the Camp 6/Cook’s Meadow area, Alternative 1 would result in the disturbance and localized removal of vegetation over approximately 6.1 acres, which includes 0.8 acre of meadow, 1.3 acres of riparian, and 1.1 acres of oak, all highly valued resources. The vegetation or cover types that would be affected by the localized removal of vegetation include Carex senta wet meadow border, Carex vesicaria wet meadow, grass meadow, oxbow and cutoff channels, mixed riparian-conifer corridor forest, impacted mixed riparian-conifer corridor forest, California black oak woodland, open ponderosa pine-California black oak woodland, developed open ponderosa pine-California black oak woodland, ponderosa pine forest, dense mixed coniferous forest, developed open area-sparse vegetation, and bare. Proposed repairs in this area would have local, short-term, minor to moderate, adverse, construction-related effects to vegetation. In addition, localized, long-term, minor loss of vegetation due to routine clearance of vegetation at utility access manholes may occur. Effects to vegetation related to construction activities would be similar to those discussed for the Happy Isles area.

The areas that would be affected are within existing utility corridors that have been previously disturbed and developed. The application of mitigation measures discussed for the Happy Isles area above would reduce these potential local, short-term, adverse, construction-related impacts to vegetation to a minor intensity

Summary of Alternative 1 Impacts

Alternative 1 would result in the disturbance and localized removal of vegetation over approximately 31 acres, which includes 3.7 acres of meadow, 2.4 acres of riparian, and 4.7 acres of oak, all highly valued resources. The areas that would be affected are all within existing corridors that have previously been disturbed and developed. Vegetation impacts in these areas are not expected to adversely impact the geographic extent, continuity, integrity, and resilience of plant communities in the Valley, but are primarily expected to be localized, short-term, minor to moderate, adverse impacts. Construction impacts can be mitigated to a minor level through the application of mitigation measures described in Chapter II, particularly those designed to address revegetation, minimization of disturbance areas, non-native species, and annosus root disease. Localized, long-term, minor loss of vegetation due to routine clearance of vegetation at utility access manholes may also continue to occur as a result of Alternative 1.

Cumulative Impacts

Cumulative effects to vegetation are based on analysis of past, present, and reasonably foreseeable future actions in Yosemite Valley in combination with potential effects of this alternative. The projects identified below include those projects that have the potential to affect local vegetation patterns.

Vegetation in Yosemite Valley has been substantially altered by development and visitor activities. These changes have negatively influenced the size, form, and function of vegetation communities and the plants and wildlife that inhabit them. Cumulative effects from future actions would be mixed, combining both adverse and beneficial effects. Cumulative beneficial effects on vegetation include restoration, rehabilitation projects, and ecosystem management. Cumulative adverse effects would be related to increased facilities and visitor demand.

Reasonably foreseeable future actions within Yosemite Valley are considered to have an overall net benefit to vegetation. For example, the Merced River Plan protects river-related natural resources through the application of management elements, including the River Protection Overlay, management zoning, protection and enhancement of Outstandingly Remarkable Values, and implementation of a Visitor Experience Resource Protection framework.

Full implementation of the Yosemite Valley Plan would restore approximately 175 acres, of which approximately 160 acres would be highly valued resource vegetation in Yosemite Valley. Such proposed actions include removal and restoration of several former campgrounds; removal of roads through Stoneman and Ahwahnee Meadows; and natural vegetation restoration actions in several areas. Alternative 1 could minimize these benefits since utilities would remain in the restoration areas and utility repairs needed in the future could continue to have short-term, localized, adverse impacts to these resources. Although certain Yosemite Valley Plan projects (such as construction of new parking and lodging facilities, and expansion of campgrounds in Yosemite Valley) have the potential to adversely affect local vegetation, these projects would be designed to ensure the long-term protection of sensitive vegetation communities consistent with the Merced River Plan and the park’s Vegetation Management Plan.

Cumulative actions could have a long-term, minor, beneficial cumulative effect on vegetation within Yosemite Valley due to the significant restoration efforts identified in the Yosemite Valley Plan. Although Alternative 1 would result in localized, short-term and long-term, minor, adverse effects, when combined with past, present, and reasonably foreseeable future actions, there is still expected to be a net long-term, minor, beneficial effect on vegetation patterns.

Impairment

The No Action Alternative would result in local, short and long-term, minor, adverse effects to vegetation due to repair and maintenance activities. Therefore, Alternative 1 would not impair the park’s vegetation resources for future generations.

Wildlife

Analysis

Under Alternative 1, the National Park Service would maintain the existing utility infrastructure in Yosemite Valley. Required maintenance and repair activities could disturb wildlife during these activities. Effects would be related to heavy equipment and human intrusion and could include noise, dust generation, vegetation removal, trench excavation, or decreased oxygen levels in aquatic habitats. These actions could result in direct losses of nests, burrows, and wildlife, and indirect effects through the disturbance of nesting birds or roosting bats. The addition of pollutants (i.e., fuels or lubricants) related to equipment operations in these areas could degrade the quality of the environment and the wildlife habitat it provides. In addition, localized, long-term, minor, adverse effects to wildlife may occur as a result of routine clearance of vegetation at utility access manholes.

Impacts associated with Alternative 1 are described by subarea below. In all subareas, the areas affected are within existing utility corridors that have been previously disturbed by utility installation and maintenance. Table IV-5 provides the acreage by subarea of vegetation community types potentially affected by Alternative 1. Meadow, riparian, and wetland habitat types are identified in the Yosemite Valley Plan as high value wildlife habitats and impacts to these habitats would have the greatest potential to adversely affect wildlife. Impacts to these high value wildlife habitats are called out specifically in the analysis below.

Happy Isles. Local, minor, short-term, adverse effects on native fish and wildlife could occur during required utility repair activities in the Happy Isles area. Repair activities would have local, short-term, adverse, construction-related effects on up to 0.6 acre, which includes 0.1 acre of riparian, a high value wildlife habitat. The wildlife habitat types that would be affected include montane riparian, ponderosa pine, sierra mixed conifer, and urban. Effects would be related to heavy equipment use and human intrusion and could include noise, dust, soil disturbance and compaction, vegetation removal, trench excavation, sedimentation, elevated turbidity, and decreased oxygen levels in aquatic habitats. These actions could result in direct losses of nests, burrows, wildlife, and reproductive habitat for aquatic organisms and indirect effects through the disturbance of nesting birds or roosting bats. The addition of pollutants (i.e., fuels, lubricants) related to equipment operations in these areas could degrade the quality of the environment and the wildlife habitat it provides. Some trees and shrubs that could provide roosts, perches, or nest sites would be removed to accommodate construction activities. Proposed repairs in this area would have local, short-term, minor, adverse, construction-related effects on wildlife. Localized, long-term, minor, adverse effects to wildlife due to routine clearance of vegetation at utility access manholes may also occur as a result of Alternative 1.

The application of mitigation measures described in Chapter II, particularly minimizing disturbance areas; installing fencing and signs to protect high value wildlife habitats; preserving, where possible, natural features with obvious high value to wildlife, such as tree snags; scheduling disruptive activities of construction in nesting habitat or hibernacula and maternity colony roosting habitat to occur outside the nesting season of birds and when bats are neither hibernating nor have young (e.g., birds breed from March to August, bats hibernate from September 1 to February 15, and bat young are nursing and unable to fly from May to mid August); instituting controls to prevent impacts to wildlife from excavations; limiting all work within the bed or banks of the Merced River to seasonal low water periods; developing and implementing a Stormwater Pollution Prevention Plan to control erosion, sedimentation, and compaction; and instituting spill prevention measures would reduce the potential adverse impacts to native fish and wildlife to a minor intensity. Additional mitigation is described under the wetland and vegetation resource areas, as it relates to wildlife habitat avoidance, the minimization of impacts to wildlife habitat, and revegetation of disturbed portions of the project area. With the application of the mitigation measures, the size, continuity, and integrity of wildlife habitats as well as the abundance, diversity, and distribution of wildlife species would not be permanently impacted by repair and maintenance activities associated with Alternative 1.

Campgrounds. Local, minor, short-term, adverse effects on native fish and wildlife could occur during utility repair activities. Construction of repairs would have local, short-term, adverse effects on approximately 2.2 acres, which includes 0.5 acre of riparian and 0.30 acre of wetland and aquatic habitat, both high value wildlife habitats. The wildlife habitat types that would be affected include fresh emergent wetland, montane riparian, montane hardwood conifer, ponderosa pine, and riverine. Effects to native fish and wildlife related to construction activities and long-term maintenance of utility access manholes would be similar to those discussed for the Happy Isles area. The application of mitigation measures as discussed above for the Happy Isles area would reduce the potential adverse impacts to native fish and wildlife to a minor intensity.

Ecological Restoration Area. Local, minor, short-term, adverse effects on native fish and wildlife could occur during utility repair activities in the Ecological Restoration area. The construction-related activities would have short-term, adverse effects on approximately 5.3 acres, which includes 1.0 acre of meadow, 0.1 acre of riparian, and 0.83 acre of wetland and aquatic habitat, all high value wildlife habitats. The wildlife habitat types that would be affected include wet meadow, montane riparian, montane hardwood conifer, ponderosa pine, sierra mixed conifer, and riverine. Effects to native fish and wildlife related to construction activities and ongoing maintenance of utility access manholes would be similar to those discussed for the Happy Isles area. The application of mitigation measures as discussed above for the Happy Isles area would reduce the potential adverse impacts to native fish and wildlife to a minor intensity.

The Ahwahnee. Local, minor, short-term, adverse effects on native fish and wildlife in The Ahwahnee area could occur during utility system repair activities. Construction-related repair activities would have short-term, adverse effects on approximately 3.6 acres, which includes 1.6 acres of meadow, 0.2 acre of riparian, and 1.55 acres of wetland habitat. The wildlife habitat types that would be affected include wet meadow, montane riparian, montane hardwood conifer, ponderosa pine, sierra mixed conifer, riverine, and urban. Effects to native fish and wildlife related to construction activities and ongoing maintenance of utility access manholes would be similar to those discussed for the Happy Isles area. The application of mitigation measures as discussed above for the Happy Isles area would reduce the potential adverse impacts to native fish and wildlife to a minor intensity.

Curry Village. Local, minor, short-term, adverse effects on native fish and wildlife could occur during utility system repair activities in Curry Village. Construction-related repair activities would have short-term, adverse effects on approximately 2.0 acres, which includes 0.06 acre of wetland habitat. The wildlife habitat types that would be affected include wet meadow, montane hardwood conifer, ponderosa pine, sierra mixed conifer, and urban. Effects to native fish and wildlife related to construction activities and ongoing maintenance of utility access manholes would be similar to those discussed for the Happy Isles area. The application of mitigation measures as discussed above for the Happy Isles area would reduce the potential adverse impacts to native fish and wildlife to a negligible to minor intensity.

Housekeeping Camp. Localized, minor, short-term, adverse effects on native fish and wildlife could occur during utility repair activities in the Housekeeping Camp area. Construction-related activities would have short-term, adverse effects on approximately 2.5 acres, which includes 0.1 acre of riparian and 0.19 acre of aquatic habitat. The wildlife habitat types that would be affected include montane riparian, montane hardwood conifer, and riverine. Effects to native fish and wildlife related to construction activities and ongoing maintenance of utility access manholes would be similar to those discussed for the Happy Isles area. The application of mitigation measures as discussed above for the Happy Isles area would reduce the potential adverse impacts to native fish and wildlife to a negligible to minor intensity.

Yosemite Village. Localized, minor, short-term, adverse effects on native fish and wildlife could occur during utility repair activities in the Yosemite Village area. The proposed construction-related activities would have short-term, adverse effects on approximately 8.7 acres, which includes 0.3 acre of meadow, 0.1 acre riparian, and 0.13 acre of wetland habitat. The wildlife habitat types that would be affected include wet meadow, montane riparian, black oak woodland, montane hardwood conifer, ponderosa pine, sierra mixed conifer, and urban. Effects to native fish and wildlife related to construction activities and ongoing maintenance of utility access manholes would be similar to those discussed for the Happy Isles area. The application of mitigation measures as described above for the Happy Isles area would reduce the potential adverse impacts to native fish and wildlife to a minor intensity.

Camp 6/Cook’s Meadow. Localized, minor, short-term effects on native fish and wildlife could occur during proposed utility repair activities in the Camp 6/Cook’s Meadow area. Construction of the required repairs would have short-term, adverse effects on approximately 6.1 acres, which includes 0.8 acre of meadow, 1.3 acre of riparian, and 0.76 acre of wetland and aquatic habitat. The wildlife habitat types that would be affected include wet meadow, montane riparian, black oak woodland, montane hardwood conifer, ponderosa pine, sierra mixed conifer, and urban. Effects to native fish and wildlife related to construction activities and ongoing maintenance of utility access manholes would be similar to those discussed for the Happy Isles area. The application of mitigation measures as described above for the Happy Isles area would reduce the potential adverse impacts to native fish and wildlife to a minor intensity.

Summary of Alternative 1 Impacts

Construction-related activities associated with Alternative 1 would have local, short-term, minor, adverse effects on approximately 31 acres, which includes 3.7 acres of meadow, 2.4 acres of riparian, and 3.82 acres of wetland and aquatic habitat. Ongoing maintenance of utility access manholes would also result in some localized, long-term, minor, adverse effects on wildlife habitats. The areas that would be affected are all within existing corridors that have previously been disturbed and developed. Wildlife impacts in these areas are related to construction activities and are expected to be localized, short-term and long-term, minor, adverse impacts. These impacts are not expected to have any long-term, adverse effect on the size, continuity, and integrity of wildlife habitats or the abundance, diversity, and distribution of wildlife species within Yosemite Valley. Construction impacts would be mitigated through the application of mitigation measures described in Chapter II, specifically minimizing disturbance areas; installing fencing and signs to protect high value wildlife habitats; preserving, where possible, natural features with obvious high value to wildlife, such as tree snags; scheduling disruptive activities of construction in nesting habitat or hibernacula and maternity colony roosting habitat to occur outside the nesting season of birds and when bats are neither hibernating nor have young (e.g., birds breed from March to August, bats hibernate from September 1 to February 15, and bat young are nursing and unable to fly from May to mid August); instituting controls to prevent impacts to wildlife from excavations; limiting all work within the bed or banks of the Merced River to seasonal low water periods; developing and implementing a Stormwater Pollution Prevention Plan to control erosion, sedimentation, and compaction; and instituting spill prevention measures.

Cumulative Impacts

Cumulative effects to wildlife are based on analysis of past, present, and reasonably foreseeable future actions within Yosemite Valley in combination with potential effects of this alternative. The projects identified below include those projects that have the potential to affect local wildlife patterns.

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

Reasonably foreseeable future actions within Yosemite Valley are considered to have an overall net benefit to wildlife. For example, the Merced River Plan protects river-related natural resources through the application of management elements, including the River Protection Overlay, management zoning, protection and enhancement of Outstandingly Remarkable Values, and implementation of a Visitor Experience Resource Protection framework. Full implementation of the Yosemite Valley Plan would increase the size, continuity, and integrity of wildlife habitats in Yosemite Valley. Although certain Yosemite Valley Plan projects (such as construction or redevelopment of facilities in Curry Village or campground areas in the east Valley) have the potential to adversely affect local wildlife, these projects must be designed to ensure the long-term protection of sensitive vegetation communities consistent with the Merced River Plan and the Vegetation Management Plan. In addition, implementation of the Visitor Experience and Resource Protection framework (included in both the Merced River Plan and Yosemite Valley Plan) will help reduce adverse effects of visitor use on wildlife habitat and patterns.

Cumulative actions would have a local, long-term, minor to moderate, beneficial cumulative effect on wildlife within Yosemite Valley. Although Alternative 1 could result in local, short-term and long-term, minor, adverse effects, these minor, adverse effects would not substantially reduce the net local, long-term, minor to moderate, beneficial effect on wildlife patterns from cumulative projects.

Impairment

The No Action Alternative would result in minor, adverse impacts to wildlife for a diversity of species in the immediate vicinity of utility repairs. However, the extent and quality of wildlife habitat for species throughout Yosemite Valley would not be substantially reduced. Therefore, Alternative 1 would not impair the park’s wildlife resources.

Special-Status Species

Analysis

Alternative 1 would continue the maintenance and operation of existing utility systems in Yosemite Valley. Special-status species known or likely to occur in the immediate vicinity of Alternative 1 include the Wawona riffle beetle, Mariposa sideband snail, Sierra pygmy grasshopper, western pond turtle, 10 species of birds, 10 species of bats, and 14 species of plants. Impacts on these species and their habitat associated with Alternative 1 are described below.

Wawona Riffle Beetle. Utility repair and maintenance activities in the vicinity of the Merced River may have localized, short-term, minor to moderate, adverse effects on the Wawona riffle beetle. Effects would be related to heavy equipment and human intrusion, and could include river-related impacts such as vegetation removal, decreased oxygen levels, the addition of silt, resuspension of sediment, or the introduction of pollutants (i.e., fuels or lubricants). These actions could result in direct losses of individuals or habitat for Wawona riffle beetle downstream of utility line river crossing repairs. The application of mitigation measures, as described in Chapter II, would reduce the potential adverse impacts to Wawona riffle beetle to a minor intensity. Specifically, these measures would involve minimizing the area disturbed and implementing Best Management Practices during construction to reduce the potential for water quality impacts associated with soil erosion and construction equipment fuel releases.

Mariposa Sideband Snail. Utility repair and maintenance activities within rockslide habitat may have localized, short-term, minor to moderate, adverse effects on the Mariposa sideband snail. Effects would be related to heavy equipment and human intrusion and could include vegetation removal, direct disturbance of rockslide habitat, or the introduction of pollutants (i.e., fuels or lubricants). These actions could result in direct losses of individuals or habitat for the Mariposa sideband snail in rockslide areas. The application of mitigation measures described in Chapter II, specifically minimizing the area disturbed, installing fencing and signs to protect sensitive habitats, and implementing spill prevention, would reduce the potential adverse impacts to the Mariposa sideband snail to a minor intensity.

Sierra Pygmy Grasshopper. Repair and maintenance activities within riparian habitats may have localized, short-term, minor to moderate, adverse effects on the Sierra pygmy grasshopper. Effects would be related to heavy equipment and human intrusion and could include vegetation removal or the introduction of pollutants (i.e., fuels or lubricants). These actions could result in direct losses of individuals or habitat for the Sierra pygmy grasshopper. The application of mitigation measures described in Chapter II, specifically, minimizing the area disturbed, timing construction in riparian habitats outside the Sierra pygmy grasshopper's active period (e.g., schedule construction for the fall or winter), and implementing pollution prevention measures, would reduce the potential adverse impacts to the Sierra pygmy grasshopper to a minor intensity.

Western Pond Turtle. Utility repair and maintenance activities in the vicinity of aquatic habitats may have localized, short-term, minor to moderate, adverse effects to the western pond turtle. Effects would be related to heavy equipment and human intrusion and could include vegetation removal, decreased oxygen levels, the addition of silt, resuspension of sediment, or the introduction of pollutants (i.e., fuels or lubricants). These actions could result in direct losses of individuals or habitat for the western pond turtle within aquatic habitats. The application of mitigation measures described in Chapter II would reduce the potential adverse impacts to western pond turtle to a minor intensity. Specifically, these measures would involve minimizing the area disturbed and implementing Best Management Practices during construction.

Special-Status Species of Birds. Utility repair and maintenance activities may have localized, short-term, minor to moderate, adverse effects on special-status birds in the immediate vicinity of construction activities. Effects would be related to heavy equipment and human intrusion and could include disruption of breeding activities or the possible direct destruction or removal of nesting habitat or sites (e.g., snags and trees). Localized, long-term, minor, adverse effects to special-status bird species and their habitat may also occur as a result of routine clearance of vegetation at utility access manholes. The application of mitigation measures described in Chapter II, specifically, limiting construction activities to outside the breeding season for special-status bird species (e.g., birds breed from March to August) and conducting pre-construction surveys in appropriate habitats if construction activities during the breeding season cannot be avoided, would reduce the potential adverse impacts to special-status bird species to a minor intensity.

Special-Status Species of Bats. Utility repair and maintenance activities may have localized, short-term, minor to moderate, adverse effects to special-status bat species in the immediate vicinity of construction activities. Effects would be related to heavy equipment and human intrusion and could include disruption of breeding activities or the possible direct destruction or removal of bat roosts (e.g., snags and trees). Localized, long-term, minor, adverse effects to special-status bat species and their habitat may also occur as a result of routine clearance of vegetation at utility access manholes. The application of mitigation measures described in Chapter II, specifically, conducting preconstruction surveys in appropriate habitats if construction activities during hibernation and nursing periods cannot be avoided, minimizing removal of large oak trees and large snags, and scheduling disruptive activities of construction in hibernacula and maternity colony roosting habitat to occur when bats are neither hibernating nor have young (e.g., bats hibernate from September 1 to February 15 and bat young are nursing and unable to fly from May to mid August), would reduce the potential adverse impacts to special-status bat species to a minor intensity.

 Special-Status Species of Plants. Utility repair and maintenance activities may have localized, short-term, minor to moderate, adverse effects on special-status plant species in the immediate vicinity of construction activities. Effects would be related to the use of heavy equipment during excavation and repair activities and could include soil disturbance and compaction, dust generation, vegetation removal, root damage, erosion, introduction and spread of non-native species, or the introduction of pollutants (i.e., fuels or lubricants). Localized, long-term, minor, adverse effects to special-status plant species may occur as a result of routine clearance of vegetation at utility access manholes. The application of mitigation measures described in Chapter II, particularly performing rare plant surveys prior to construction in appropriate habitats and at appropriate times (e.g., during plant species flowering periods), avoiding special-status species of plants to the extent possible, minimization of disturbance areas, and implementing a noxious weed abatement program, would reduce the potential adverse impacts to special-status plant species to a minor intensity.

Summary of Alternative 1 Impacts

Alternative 1 would likely result in local, minor, short-term, adverse impacts to special-status species during construction of utility repairs and local, long-term, minor, adverse effects to special-status species as a result of routine clearance of vegetation at utility access manholes. These impacts are not expected to adversely affect the viability of these species or to have long-term adverse effects on their abundance or distribution. Implementation of mitigation measures to reduce impacts to special-status species are expected to minimize the adverse impacts.

Cumulative Impacts

Cumulative effects to special-status species are based on analysis of past, present, and reasonably foreseeable future actions within Yosemite Valley in combination with potential effects of this alternative. The projects identified below include those projects that have the potential to affect local special-status species.

Natural habitats in Yosemite Valley have been manipulated since the inception of Yosemite National Park. Regional wildlife and vegetation patterns have been historically affected by logging, fire suppression, rangeland clearing, grazing, mining, draining, damming and diversions, and the introduction of non-native species. Past and ongoing activities that affect special-status species include recreational use and construction of bridges, diversion walls, roads, pipelines, riprap, buildings, campgrounds, and other recreational features.

Reasonably foreseeable future actions within Yosemite Valley are considered to have an overall net benefit to special-status species. For example, the Merced River Plan protects river-related natural resources through the application of management elements, including the River Protection Overlay, management zoning, protection and enhancement of Outstandingly Remarkable Values, and implementation of a Visitor Experience Resource Protection framework.

Full implementation of the Yosemite Valley Plan would increase the size, continuity, and integrity of habitats, especially meadow, riparian, California black oak, and upland habitats, for special-status species in Yosemite Valley. Although certain Yosemite Valley Plan projects, such as construction of new lodging and parking facilities, and expansion of campgrounds in the east Valley, have the potential to adversely affect local special-status species, these projects must be designed to ensure the long-term protection of special-status species consistent with the Merced River Plan and the Endangered Species Act. In addition, implementation of the Visitor Experience and Resource Protection framework (included in both the Merced River Plan and Yosemite Valley Plan) will help reduce adverse effects of visitor use on special-status species.

Cumulative actions would have a local, long-term, moderate, beneficial cumulative effect on special-status species within Yosemite Valley. Thus, past, present, and reasonably foreseeable future actions, in combination with the local, short-term, minor, adverse effects from Alternative 1, would have a net local, long-term, minor to moderate, beneficial effect on special-status species.

Impairment

The No Action Alternative would result in a local, short-term, minor, adverse impact to special-status species in the immediate vicinity of utility repair activities. The extent and quality of habitat for these species within Yosemite Valley would remain unaffected. Therefore, Alternative 1 would not impair the park’s special-status species resources for future generations.

Air Quality

Analysis

Although pollutant emissions resulting from implementation of Alternative 1 could contribute to an impact on air quality in Yosemite Valley, air quality is a regional issue that is more influenced by regional factors. Therefore, the air quality analysis presented below is not discussed by the nine subareas discussed in other resource sections. This section presents a qualitative assessment of air emissions related to continued operation of existing utility systems in Yosemite Valley, including construction emissions related to wastewater line repairs required by the California Regional Water Quality Control Board and discussed in Chapter II.

Alternative 1 would include use of construction equipment to repair the existing wastewater system. Air quality effects from this alternative would relate primarily to construction equipment emissions and dust generated during planned repair activities. Emissions from construction equipment would occur in the vicinity of utility repair projects and could result in mildly unpleasant odors that could be noticeable to park visitors in nearby areas. Construction activities in each area are expected to be of relatively short duration, and many repairs would be timed during the fall and winter when visitor levels in the park are at their lowest. Use of Best Management Practices (e.g., site watering, covering stockpiles, covering haul trucks, or vehicle emission controls) to reduce both tailpipe and fugitive dust emissions would be made a condition of construction contractor agreements.

Alternative 1 would not result in any change in long-term operating emissions related to Yosemite Valley utilities systems.

Summary of Alternative 1 Impacts

Alternative 1 would result in local, short-term, minor, adverse impacts to air quality. There would be no long-term effect on regional air quality under this alternative.

Cumulative Impacts

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

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 associated emissions from industrial, commercial, and vehicular sources in upwind areas. 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 become congested. 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 visitors leave the Valley) to stabilize traffic conditions.

The Yosemite Area Regional Transportation System (YARTS) is a multi-agency effort to provide transportation options, reduce reliance on automobiles, and improve regional air quality. Efforts underway under this project are expected to result in long-term, beneficial impacts on air quality throughout the region.

The Yosemite Valley Plan proposes to enhance the quality of the visitor experience in Yosemite Valley by reducing automobile congestion and limiting crowding. It also proposes traffic management systems and options for the size and placement of parking lots, both within and outside of 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 would have a long-term, moderate, adverse impact on nitrogen oxide emissions from the use of diesel buses through 2015, but long-term, minor to major, beneficial impacts to volatile organic compounds, carbon monoxide, and particulate matter emissions.

The purpose of the Merced River Plan is to protect and enhance the Outstandingly Remarkable Values and free-flowing condition of the river for the benefit and enjoyment of present and future generations. The protection of natural resources under this plan would benefit air quality.

Reasonably foreseeable future actions proposed for Yosemite Valley could have beneficial or adverse impacts on air quality. For example the National Park Service’s Shuttle Bus Replacement Project could have a net beneficial effect on air quality by improving the attractiveness of alternative modes of transportation and thereby reducing private automobile trips. Although the Shuttle Bus Replacement Project would have localized, short-term, adverse air quality effects, the general goal of the project is to relieve congestion and provide for alternative means of transportation. As such, this project would encourage travel to the park by alternative (nonprivate vehicle) modes and would have a long-term, beneficial effect on air quality.

Other reasonably foreseeable future National Park Service projects, such as the Eagle Creek Merced River Ecological Restoration Project and Trail Reconstruction from Happy Isles to Vernal Fall, are not anticipated to have a net adverse or beneficial effect on air quality except for short-term, localized impacts during construction.

Although cumulative growth in the region will tend to adversely affect air quality, implementation of ongoing state and federal mobile-source control programs would ameliorate this effect to a degree. With respect to particulate matter, conditions in the Valley would be determined by both regional sources and local sources and could be beneficial or adverse. Considered with the adverse impacts associated with regional air quality influences, the cumulative projects would have a local, long-term, moderate, beneficial effect on air quality in Yosemite Valley.

Alternative 1 and the cumulative projects would result in local, long-term, moderate, beneficial impacts on air quality. The local, short-term, adverse effects associated with construction emissions from repair activities on the existing utility systems would not offset the long-term, beneficial effects of the cumulative projects.

Impairment

Implementation of Alternative 1 is expected to result in local, short-term, minor, adverse impacts to air quality from construction activities. These short-term impacts are not expected to impair park resources for future generations.

Noise

Analysis

Utility repair activities proposed under Alternative 1 would involve operation of heavy-duty equipment at repair sites, which could generate substantial amounts of noise during these operations. Since utility infrastructure is located throughout Yosemite Valley and repairs are required in many areas, park visitors and employees could be impacted during construction activities. Table IV-6 provides typical noise levels generated by construction equipment. Noise in the area of repair operations would vary depending on a number of factors, such as the number and type of equipment in operation on a given day, usage rates, the level of background noise in the area, and the distance between sensitive uses and the construction site.

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Table IV-6

Typical Noise Levels from Construction Equipment

 

dBA = A-weighted decibels

SOURCES:  Federal Transit Authority 1995
 

Winter ambient noise levels at various locations in Yosemite Valley ranged from 59 to 69 day-night level (DNL) in 1999 (NPS 2000 ). Summer ambient noise levels would be expected to be higher because of the level of visitation and activity during the summer. Construction noise would be loudest immediately adjacent to the construction area, but due to generally low background sound levels in Yosemite Valley, the noise may be audible a long distance from the source. Some construction equipment and activities can produce sounds in excess of 100 dB, typically in short bursts over the duration of the project. These noises would be perceived as 16 or more times as loud as a typical vehicle.

Noise impacts would be mitigated through scheduling repair operations during daytime hours and avoiding peak visitor periods whenever possible, using hydraulic or electric powered tools when feasible, and requiring the use of best-available noise control techniques.

Happy Isles. Utility repairs in the Happy Isles area could result in short-term noise impacts on visitors to the Happy Isles Nature Center or those hiking in the area. These impacts could be moderate to major in intensity, but would be short-term in duration.

Campgrounds. Campground utility repairs would most likely be scheduled to occur during the fall or winter, when visitor numbers are low. Although North Pines and Lower Pines Campgrounds are closed during the winter, Upper Pines Campground remains open and visitors camping or hiking in this area could be impacted by construction noise as utility lines are repaired. In addition, construction noise could result in short-term, moderate, adverse effects to other park visitors farther removed from the repair sites. Utility system repairs at each repair site would be short-term in duration.

Ecological Restoration Area. Construction of wastewater line repairs in the Ecological Restoration area could result in short-term noise impacts to visitors in the vicinity of Housekeeping Camp and along the road north of Stoneman Bridge. These repairs would most likely be scheduled to occur during fall or winter periods when visitor numbers are low and Housekeeping Camp is closed to park visitors. Park contractors camped in Housekeeping Camp could be impacted. These construction noise impacts are expected to be moderate to major in intensity, but short-term in duration.

The Ahwahnee. The Ahwahnee area utility repairs could result in construction noise impacts on park visitors in The Ahwahnee hotel area as well as residents in the Tecoya Housing area. Construction noise impacts would be adverse, local, moderate to major in intensity, and short-term in duration.

Curry Village. The utility repair activities in Curry Village would result in construction noise impacts on park residents and visitors in the Curry Village area. These noise impacts would be local, short-term, moderate to major, adverse effects.

Housekeeping Camp. Repairs in Housekeeping Camp would likely be scheduled to occur during fall or winter, after Housekeeping Camp has closed for the season to park visitors. Park contractors using these facilities during construction periods could be impacted. These construction-related impacts would be adverse, local, moderate to major in intensity, and short-term in duration.

Yosemite Village. Construction of utility repairs in the Yosemite Village area would result in local, short-term, moderate to major, adverse noise effects on residents and visitors in this area.

Camp 6/Cook’s Meadow. Repairs to utility facilities located in the Camp 6 and Cook’s Meadow areas would result in local, short-term, moderate to major, adverse noise effects on park visitors and residents.

Summary of Alternative 1 Impacts

Utility repairs required for ongoing operation and maintenance of existing utility infrastructure would result in local, short-term, moderate to major, adverse impacts to park visitors, residents, and contractors in the vicinity of repair projects. This alternative is not expected to have any long-term impact on ambient noise levels in Yosemite Valley.

Cumulative Impacts

Cumulative effects to the ambient noise environment are based on the analysis of past, present, and reasonably foreseeable future actions in Yosemite Valley in combination with potential effects of this alternative. The projects identified below include those projects within Yosemite Valley that could affect noise within the Valley.

The Yosemite Valley Plan proposes to enhance the quality of the visitor experience in Yosemite Valley by reducing automobile congestion, limiting crowding, and expanding orientation and interpretation services. It also proposes traffic management systems and options for the size and placement of parking lots, both within and outside of Yosemite Valley. Parking lots outside the Valley could be used to intercept day visitors and shift those visitors to Valley-bound shuttle buses. Overall, general sound levels associated with traffic along most roadways in the Valley would be reduced, representing a long-term beneficial impact.

The purpose of the Merced River Plan is to protect and enhance the Outstandingly Remarkable Values and free-flowing condition of the river for the benefit and enjoyment of present and future generations. The protection of natural resources and maintenance of visitor-intensive uses in the appropriate management zones under this plan would have beneficial effects on the noise environment.

Reasonably foreseeable future actions proposed for Yosemite Valley could have beneficial or adverse impacts on noise. For example, the National Park Service’s Shuttle Bus Replacement Project could have a net beneficial effect on the ambient noise environment by improving the attractiveness of alternative modes of transportation, thereby reducing private automobile trips. Although the Shuttle Bus Replacement Project would increase the frequency of bus trips and related localized, short-term, adverse noise effects, noise levels generated by the individual buses will decrease. The general goal of the project is to relieve congestion and provide for alternative means of transportation. As such, this project would encourage travel to the park by alternative (nonprivate vehicle) modes and would have a long-term, beneficial effect on noise. To the extent that transportation-related projects would replace automobile trips in the Valley with bus trips, the anticipated beneficial effect would depend on ridership levels (and the corresponding number of automobile trips that would be avoided) and the technology selected for the buses.

Other reasonably foreseeable future National Park Service projects, such as Eagle Creek Merced River Ecological Restoration and Happy Isles to Vernal Fall Trail Reconstruction, are not anticipated to have a net adverse or beneficial effect on the ambient noise environment except for short-term, localized impacts during construction.

The gradual increase in annual visitation to the park would likely offset the beneficial effects of cumulative actions that would tend to reduce vehicle trips and their associated noise, resulting in a local, long-term, minor, adverse effect on the noise environment. Alternative 1 would contribute to this impact in the short term.

Impairment

The No Action Alternative would result in a local, short-term, moderate, adverse effect on noise in Yosemite Valley during construction activities associated with repairs to existing utility facilities. Alternative 1 is not expected to have any long-term, adverse noise effects and is not expected to impair park resources for future generations.

Cultural Resources

As described in Chapter III, cultural resources in Yosemite Valley include prehistoric and historic archeological sites, historic structures, other elements of the cultural landscape that are older than 50 years, American Indian traditional resource gathering areas, and other places and resources to which culturally associated American Indians attach religious and cultural significance. Impacts that would result from activities proposed under Alternative 1 would affect these different resource types in various ways. How the significance of the potential impacts is gauged also varies by resource type.

Archeological Resources

Analysis

Much of the utility infrastructure in Yosemite Valley was installed with little consideration for buried cultural resources prior to the passage of resource conservation legislation and the establishment of federal agency compliance programs. Excavation of trenches for utilities and various construction activities have occurred throughout the Valley, disturbing archeological material to varying degrees depending on the extent of development and the density of cultural material. The same can be said of development of the transportation infrastructure through time, which often overlapped with utilities corridors and will likely continue to do so.

Despite the disturbance that can be anticipated from previous development activities throughout the Valley, intact archeological deposits are known to exist even in the most highly developed areas such as Yosemite Village. Archeological monitoring of utility upgrades in the 1980s and 1990s revealed the presence of extensive intact archeological deposits with no surface evidence, often immediately adjacent to previous construction sites or under existing roads and developed trails. Monitoring allows for identification of unknown resources and continuous examination of archeological deposits in areas previously determined to be disturbed or of low information potential. This allows for constant reassessment of those determinations if a feature or higher density concentration of undisturbed materials is revealed. The monitoring archeologist has the opportunity to collect items or samples of particular interest, or to halt excavation long enough to excavate particular deposits if need be, thus conducting data recovery where needed. In this way, monitoring serves as a secondary layer of assurance that significant information regarding the cultural materials will be incorporated into the data base that informs about the nature of previous lifeways and can be used to inform planning and compliance needs for future activities. Subsurface testing of known sites is itself damaging to potential archeological deposits, so testing is not typically conducted on a Valley-wide basis, but only where potential effects from proposed activities may occur.

For construction activities related to repair of existing utilities, sediments in the existing utility corridors are disturbed to the extent of the previous excavation. Although the extent of the previous excavations is unknown, it likely varied considerably. Even if the extent of previous excavations was known, control during re-excavation could not be precise enough to ensure that no new impacts would occur to adjacent buried cultural materials, either previously recorded or unknown.

Some general approaches are recommended to avoid or mitigate potential direct and indirect impacts to archeological resources in addition to those included in the Construction Mitigation Measures and Resource Specific Mitigation Measures in Chapter II. Excavations at manholes (either for removal of the manhole or for pipe bursting activities) should be limited to the sediments that are disturbed from the previous excavation when the manhole was first installed. If it is determined that proposed excavations at manholes within or adjacent to recorded sites may exceed the area of previously disturbed sediments, these areas would be tested prior to construction activities and data recovery, if required based upon testing, would occur.

Potential indirect impacts on cultural resources could occur as a result of changes in traffic patterns during construction-related detours. Changed foot traffic patterns could bring visitors into contact with cultural resources in places they normally would not travel through. A similar effect is possible with vehicle traffic if detours increase visitation at locations typically not as popular. This could bring an increased number of people into contact with normally isolated or hard-to-find cultural resources. This would be a short- and potentially long-term, but probably minor impact when compared to all potential visitor contacts with all cultural resources. However, detours would be formalized whenever the use of a traffic route is blocked or impaired by construction and related activities. Foot traffic would be directed to follow established detours, and efforts would be made to limit detours to constructed paths as much as possible. There is also a potential for illegal collection of cultural material or vandalism during archeological excavations associated with the project. Efforts would be made to limit visitor access to site areas during excavation activities and to secure subsurface exposures at night.

The actions in Alternative 1, which are designed to repair and maintain existing utility facilities, will include clearing of vegetation, trenching, filling, grading, and other earthmoving activities. These activities have the potential to affect several recorded archeological sites and may impact unrecorded buried cultural resources. Monitoring of excavations by archeologists, a standard procedure for ground-disturbing activities in Yosemite National Park, would reduce potential impacts associated with discovery of unrecorded cultural resources. Impacts associated with Alternative 1 are described by subarea below.

Happy Isles. Construction activities in the Happy Isles area would include repairs to the existing wastewater line. While there are no recorded archeological sites within the Area of Potential Effect for Alternative 1 in the Happy Isles area, minimizing the area disturbed and monitoring excavation would reduce the potential for impacts to unrecorded buried cultural material.

Campgrounds. In the Upper Pines Campground, Alternative 1 construction activities would include installation of a new manhole and spot repairs to the existing wastewater lines serving the campground. These activities have the potential to impact important deposits at one archeological site. The site is a prehistoric American Indian habitation site considered to be of moderate data potential. The site has not been subject to test excavations to determine its nature, extent, integrity and specific data potential; the boundaries are based only on surface observations and its potential eligibility for inclusion in the National Register of Historic Places is unknown. Since the site is currently recorded only based on surface evidence,testing would be conducted on this site prior to construction. Data recovery, if determined to be required after testing, would be carried out in accordance with the 1999 Programmatic Agreement to retrieve any important information, thereby reducing the intensity of long-term, adverse impacts from moderate to minor.

Ecological Restoration Area. There are no recorded archeological sites within the Area of Potential Effect for Alternative 1 in the Ecological Restoration Area. Minimizing the area disturbed and monitoring excavation would reduce the potential for impacts to unrecorded buried cultural material.

The Ahwahnee. Three sites in The Ahwahnee area with high data potential may be impacted by proposed pipe bursting repairs. Potential impacts to important cultural material at two of the sites would be avoided by limiting the excavation at the manholes to the area originally excavated for their installation. The third site is an archeological site that encompasses the area around The Ahwahnee and includes evidence of both historic Euroamerican and prehistoric American Indian habitation. Limiting construction activities to the previously disturbed sediments around the existing manholes would avoid potential impacts to any intact buried cultural material that may be present at this location.

Curry Village. Intact sediments at two archeological sites in the Curry Village area may be disturbed by grading, trenching, and earthmoving activities necessary to repair existing utilities under Alternative 1. These sites are prehistoric American Indian and historic Euraomerican habitation sites ranging in estimated data potential from low to moderate. Proposed replacement of a wastewater line in this area will impact one unevaluated site. This site has not been subject to test excavations to determine its nature, extent, integrity and specific data potential, so the boundaries are based only on surface observations and its potential eligibility for inclusion in the National Register of Historic Places is unknown. The site will be evaluated through test excavations, and where utility line construction would result in loss of important archeological information, data recovery to retrieve important information, carried out in accordance with the 1999 Programmatic Agreement, would reduce the intensity of permanent adverse impacts from major to minor. In addition, the proposed replacement of another wastewater line in this area by pipe bursting has the potential to impact another site recorded directly to the south. In this case, while the site boundaries have not been determined by testing, potential impacts to any intact cultural materials at the site would be avoided by limiting the excavation at the three manholes to the areas originally excavated for their installation.

Housekeeping Camp. There are no recorded archeological sites within the Area of Potential Effect for Alternative 1 in the Housekeeping Camp area. Minimizing the area disturbed and monitoring excavation would reduce the potential for impacts to unrecorded buried cultural material.

Yosemite Village. Much of the area encompassed by Yosemite Village includes archeological sites that were originally recorded as seven separate sites but now are collectively referred to as a single site area representing prehistoric and historic American Indian and historic Euroamerican habitation. The collective site has been proven through previous evaluation and monitoring projects to have many areas of important archeological deposits. Impacts to this site area from the work proposed under Alternative 1 would be direct and major and would require data recovery excavations, in accordance with the 1999 Programmatic Agreement, to mitigate effects to the important deposits within the area of the site that would be impacted by construction. In addition, burials have been located within the site area and the proposed work would have to be monitored according to the terms of an inadvertent discovery plan prepared in consultation with Indian tribes and the State Historic Preservation Officer prior to construction. Construction activities that are of particular concern include those proposed in the western one-third of the Yosemite Village area. Data recovery excavations would have to follow a research design with goals consistent with those in Hull and Moratto (1999). With appropriate data recovery in accordance with the 1999 PA, the adverse impacts would be mitigated from moderate to minor level.

Camp 6/Cook’s Meadow. A proposed spot repair along the wastewater line in the Camp 6/Cook’s Meadow area has the potential to impact one site of high data potential. This site has been evaluated and potential impacts to important deposits would be mitigated through data recovery, carried out in accordance with the 1999 Programmatic Agreement, to reduce the intensity of permanent adverse impacts from moderate to minor.

Summary of Alternative 1 Impacts

Alternative 1 consists exclusively of repairs or upgrades within existing utility trenches, therefore, the number of archeological resources that could receive adverse effects would be more limited than for the other alternatives. Alternative 1 has the potential to affect eight known sites. Of these sites, one has low data potential, two have moderate data potential, and five have high data potential. Impacts to four of these sites will be avoided by limiting excavation to previously disturbed manhole areas.

Data recovery excavations are known to be needed in one area at Yosemite Village to mitigate potential effects prior to construction. National Register evaluation testing would occur at three other sites in order to determine whether the proposed effects would be adverse. If it is determined that the sites are eligible for the National Register of Historic Places, data recovery excavation to retrieve important information, carried out in accordance with the 1999 Programmatic Agreement, would occur prior to construction to mitigate the adverse effect under the National Historic Preservation Act and reduce the intensity of permanent, adverse impacts to minor under NEPA.

Cumulative Impacts

Cumulative impacts to archeological resources are based on analysis of past, present, and reasonably foreseeable future actions in Yosemite Valley in combination with potential effects of this alternative. Assessment of cumulative effects is hampered by a lack of information for untested sites throughout the Valley. Development of facilities within Yosemite Valley has disturbed or destroyed numerous archeological resources and compromised the integrity of numerous other such resources, which has had an adverse cumulative effect on archeological resources.

Reasonably foreseeable future actions proposed in the region that could have an adverse cumulative effect on archeological resources in Yosemite include any development-related projects that include excavation, such as Curry Village Employee Housing, Eagle Creek Merced River Ecological Restoration, Ecological Restoration of Flood-Damaged Campgrounds, Lower Yosemite Fall Project, and Curry Village and East Yosemite Valley Campground Improvements. Excavations and other construction activities related to these cumulative projects could disturb individual archeological resources, which are located throughout the Valley. The Yosemite Valley Plan would have a local, long-term, adverse cumulative effect on cultural resources in Yosemite Valley due to possible disturbance associated with earth-moving, construction, and demolition projects. The National Park Service would follow stipulations of the 1999 Programmatic Agreement and would avoid and mitigate adverse effects to archeological resources to the greatest extent feasible.

The Merced River Plan provides a framework for decision-making on future management actions within the Merced River corridor through the application of a consistent set of decision-making criteria and considerations composed of seven management elements: boundaries, classifications, Outstandingly Remarkable Values, the Section 7 determination process, management zoning, the River Protection Overlay, and the Visitor Experience and Resource Protection framework. The Merced River Plan calls for protection of cultural resources and would have a local, long-term, minor, beneficial cumulative effect on archeological resources.

The cumulative projects within and in the vicinity of the Yosemite Valley would result in a local, long-term, negligible to minor, adverse impact on archeological resources due to the potential disturbance of such resources during subsurface excavations associated with development projects. Alternative 1 is likely to contribute to this adverse effect; however, mitigation of adverse effects will occur through data excavation and recovery in compliance with the 1999 Programmatic Agreement. Therefore, Alternative 1 and the cumulative projects within the Valley would result in a local, long-term, negligible to minor, adverse impact on archeological resources.

Impairment

Although highly valued cultural resources are located within the Area of Potential Effect for Alternative 1, the effect of this alternative on archeological resources would be primarily localized and mitigated where required through data recovery to retrieve important information, carried out in accordance with the Programmatic Agreement. Therefore, this alternative would not impair the park’s resources for future generations.

Traditional Cultural Resources

Analysis

Several of the actions in Alternative 1 would occur within areas identified as historic American Indian habitation sites, traditional cultural resource gathering locations, and other areas and resources to which the Native Americans attach religious and cultural significance. These resource areas may be eligible to the National Register of Historic Places as Traditional Cultural Properties. Although Bibby (1994) recommended that the entire Yosemite Valley be nominated to the National Register of Historic Places as a Traditional Cultural Property, the individual traditional cultural resources in the Valley have not been evaluated. Under the National Historic Preservation Act, if not yet evaluated, historic properties must be managed as if they are National Register of Historic Places eligible resources. The severity of potential impacts to traditional cultural properties can only be determined in consultation with the people who place a cultural value on the resource. Implementation of the construction mitigation measures described in Chapter II can limit disturbances within these resource areas, but determining how to mitigate potential direct and indirect impacts to the cultural value of the property must come through consultation with the affected party(s). The park participates in ongoing consultation with American Indian tribes that are culturally associated with traditional cultural resources in the Valley regarding the potential impacts and mitigation measures to address the impacts.

Potential effects to traditional cultural resources are discussed for each of the project subareas below.

Happy Isles. Although no specific known traditional cultural resources have been identified within the Area of Potential Effects for Alternative 1 in the Happy Isles area, it is likely that traditionally used plants occur in the area. Construction activities in the area would be expected to result in local, short-term, minor, adverse effects.

Consultation regarding these effect and appropriate mitigation measures has identified the need for minimizing disturbance of areas that have not previously been disturbed; soil storage, salvage, and disposal measures to ensure regeneration of native species and reduce the potential for introduction of invasive species; and tribal participation in the development and implementation of revegetation plans for disturbed areas. Monitoring of construction activities will also be conducted within the traditional cultural resource areas as a standard procedure for any ground-disturbing activities in the Valley. See the mitigation measures discussion in Chapter II for a detailed list of mitigation measures incorporated into the project to address traditional cultural resources.

Campgrounds. Traditional cultural resources that could be affected by proposed wastewater line repairs in the Campgrounds area include a historic American Indian habitation site (Ummataw) in the Upper Pines Campground and two gathering areas for mushrooms, a traditional cultural resource, within the North Pines Campground and the proposed Tenaya Creek Campground area. Construction activities in the area would be expected to result in local, short-term, minor, adverse effects on traditional cultural resources.

Consultation regarding these effects and appropriate mitigation measures has identified mitigation measures described above under the Happy Isles subsection and in the discussion of mitigation measures in Chapter II of this document. In addition, archeological sites have been identified at several of the locations designated as historic American Indian habitation sites, and specific mitigation recommendations have been made where the proposed construction activities may impact subsurface cultural material.

Ecological Restoration Area. Although no specific known traditional cultural resources have been identified within the Area of Potential Effect for Alternative 1 in the Ecological Restoration area, it is likely that some traditionally utilized plant resources are present. Construction activities in this area would likely result in local, short-term, minor, adverse impacts. Consultation has identified mitigation measures to minimize adverse effects as discussed above under the Happy Isles subarea and in the mitigation measure discussion in Chapter II.

The Ahwahnee. Proposed utility repairs in this area could impact a historic American Indian habitation site (Wiskalah). Construction activities in this area would likely result in local, short-term, minor, adverse impacts. Consultation has identified mitigation measures to minimize adverse effects as discussed above under the Happy Isles subarea and in the mitigation measures discussion in Chapter II.

Curry Village. Although no specific known traditional cultural resources have been identified within the Area of Potential Effect for Alternative 1 in the Curry Village area, there is a possibility that traditionally used plant resources are present in the area. Construction activities in this area would likely result in local, short-term, minor, adverse impacts to these resources. Consultation has identified mitigation measures to minimize adverse effects as discussed above under the Happy Isles subarea and in the mitigation measures discussion in Chapter II.

Housekeeping Camp. Proposed utility repairs in the Housekeeping Camp area could affect a historic American Indian habitation site (Holow/Tuyuyuyu). Construction activities in this area would likely result in local, short-term, minor, adverse impacts. Consultation has identified mitigation measures to minimize adverse effects as discussed above under the Happy Isles subarea and in the mitigation measures discussion in Chapter II.

Yosemite Village. Proposed utility repairs in the Yosemite Village area could affect the historic American Indian habitation sites of Ahwahnee and Yowatchke as well as traditional California black oak use areas. Construction activities in this area would likely result in local, short-term, minor, adverse impacts. Consultation has identified mitigation measures to minimize adverse effects as discussed above under the Happy Isles subarea and in the mitigation measures discussion in Chapter II.

Camp 6/Cook’s Meadow. Activities proposed under Alternative 1 in the Camp 6/Cook’s Meadow area could affect a traditional strawberry gathering area and a mushroom gathering area. Construction activities in this area would likely result in local, short-term, minor, adverse impacts. Consultation has identified mitigation measures to minimize adverse effects as discussed above under the Happy Isles subarea and in the mitigation measures discussion in Chapter II.

Summary of Alternative 1 Impacts

Activities proposed under Alternative 1 could adversely affect known and unknown traditional cultural resources, including six traditional gathering areas and five historic Native American habitation sites. Because activities at these locations would be short-term and localized, construction activities in this area would likely result in local, short-term, minor, adverse impacts. Consultation has identified mitigation measures to minimize adverse effects as discussed above under the Happy Isles subarea and in the mitigation measure discussion in Chapter II. Implementation of these mitigation measures is expected to mitigate the adverse effect under the National Historic Preservation Act and reduce the intensity of long-term, adverse impacts to minor under NEPA.

Cumulative Impacts

Cumulative impacts to traditional cultural resources discussed herein are based on analysis of past, present, and reasonably foreseeable future actions in Yosemite Valley in combination with potential effects of this alternative. Development, operation, and maintenance of facilities in the Valley has disturbed, destroyed, or impacted the integrity of numerous traditional cultural resources, which has had an adverse cumulative effect. Nevertheless, Yosemite National Park retains many sites and resources of significance to local and culturally associated American Indians.

Reasonably foreseeable future actions proposed in the region, including development and maintenance projects under the Yosemite Valley Plan, could have an adverse cumulative effect on traditional cultural resources. Projects proposed under the Yosemite Valley Plan would result in expanded development and disturbance of traditional gathering areas and historic American Indian habitation sites. In recognition of the potential for future impacts to traditional cultural resources, the park entered into an agreement with the American Indian Council of Mariposa County, Inc. in 1997 regarding the conduct of traditional activities in Yosemite National Park, and committed to consultation with all culturally associated American Indian entities under the 1999 Programmatic Agreement.

The Merced River Plan was developed to guide decision-making on proposed actions within the Merced River corridor by applying consistent decision-making criteria and management zone policies to development in this area. Although these guidelines include protection of cultural resources, they do allow for development that could result in adverse effects on traditional cultural resources.

Other planned projects (such as the Ecological Restoration of Flood-Damaged Campgrounds and the Eagle Creek Merced River Ecological Restoration) call for restoration of native vegetation, which could have a long-term, beneficial effect on traditional cultural resources.

Cumulatively, these projects would be expected to have a local, long-term, minor, adverse effect on traditional cultural resources. Alternative 1 could contribute to this minor, adverse effect.

Impairment

Alternative 1 is relatively limited in scope and would not change the management or treatment of traditional cultural resources in Yosemite Valley. This alternative is not expected to result in impairment of the traditional cultural resources present in the park.

Cultural Landscape Resources, Including Historic Sites and Structures

Alternative 1 would not change the management and treatment of historic structures and contributing elements of the cultural landscape. These resource types have little potential to be directly impacted by the activities proposed for Alternative 1 because of the narrow Area of Potential Effect for the project. The only historic resources known within the direct impact area are the utilities themselves where they are at least 50 years old and retain properties that can offer information to interpretation of the development of Yosemite Valley. For the latter, the utilities could contribute to a description of the infrastructure that was put in place throughout the development of the Valley for its different uses in the historic era. However, the degree of alteration of the utilities infrastructure over time suggests that integrity of this resource is lacking, and better information to describe the development of the Valley’s infrastructure may be available in park planning and maintenance records.

Some indirect effects could result from actions proposed under Alternative 1, such as intrusions on visual sight from a building (viewshed) where the setting contributes to the building’s significance (e.g., The Ahwahnee). Increased dust, noise, and increased or decreased access may also adversely affect historic resources. Under Alternative 1, all of these indirect effects would be short-term and minor. Direct impacts on the cultural landscape of the actions proposed for Alternative 1 are expected to be short-term and negligible and would be adequately addressed by the construction mitigation measures discussed in Chapter II.

The Ahwahnee. Alternative 1 has the potential to impact historic resources only within The Ahwahnee area. As noted above in the discussion of Archeological Resources, pipe bursting repair activities are proposed to occur immediately south of The Ahwahnee. These repairs have the potential to impact buried cultural material in this area. While the hotel would not experience any direct impacts, it is included in the historic property site record for the archeological site, acknowledging the overlap between the built and subsurface, historic-era archeological resource at this location. Indirect effects to The Ahwahnee that may result from excavation of the manhole vaults (e.g., noise or dust generation) would be short-term and of negligible intensity and would be adequately addressed by the construction mitigation measures and the resource specific mitigation measures for cultural resources described in Chapter II.

Summary of Alternative 1 Impacts

Because Alternative 1 would consist exclusively of repairs or upgrades within existing utility trenches, no direct National Historic Preservation Act effects or NEPA impacts to historic structures or the cultural landscape are anticipated. Potential indirect impacts would be adequately addressed by the mitigation measures described in Chapter II.

Cumulative Impacts

Cumulative impacts to historic resources and cultural landscape resources are based on analysis of past, present, and reasonably foreseeable future actions in Yosemite Valley in combination with potential effects of this alternative. Past development, visitor use, and natural events have resulted in adverse cumulative impacts to historic resources and the cultural landscape. Over time, structures and sites such as homestead cabins, barns, road and trail segments, bridges, mining complexes, railroad and logging facilities, historic tourist facilities, blazes, and campsites have been affected. These resources are reminders of the Valley’s ranching, grazing, lumbering, and mining history as well as early tourism.

Reasonably foreseeable future actions that could affect historic and cultural landscape resources in the Valley include several proposals within the Yosemite Valley Plan. The Yosemite Valley Plan would result in the removal, relocation, or modification of historic buildings and structures, and the introduction of modern facilities and development within historic districts and contributing portions of the cultural landscape. The Yosemite Valley Plan also would restore native vegetation communities to patterns more in keeping with the cultural landscape and historic setting of the Valley. Overall, implementation of the Yosemite Valley Plan would adversely affect the cultural landscape. Protection of cultural resources is an integral component of the Merced River Plan. The plan provides a framework for decision-making on future management actions within the Merced River corridor through the application of a consistent set of decision-making criteria and consideration of specific management elements. The plan would have a beneficial cumulative effect on cultural resources, including historic structures and cultural landscape resources.

The cumulative projects in Yosemite Valley would result in a local, long-term, minor, adverse impact on historic resources and the cultural landscape due to the disturbance of such resources from planned projects. Alternative 1 and the cumulative projects in Yosemite Valley would result in a local, long-term, minor, adverse impact on historic and cultural landscape resources.

Impairment

Alternative 1 would have negligible adverse effects on historic and cultural landscape resources and would not impair the park’s historic site or cultural landscape resources for future generations.

Section 106 Summary for Alternative 1

Under regulations of the Advisory Council on Historic Preservation (36 CFR 800.9) addressing the criteria of effect and adverse effect, the National Park Service finds that the continuation of current park utility operations, including repairs and maintenance, would have the potential to adversely affect significant historic properties. Some archeological sites may be at risk of disturbance during construction of the required wastewater system repairs. If archeological sites could not be avoided, monitoring and data recovery carried out in accordance with the 1999 Programmatic Agreement would retrieve important information from the disturbed resources, thereby avoiding adverse impacts. Traditional cultural resources may also be disturbed during utility repairs in these areas. The park has developed mitigation measures through consultation with culturally associated American Indians groups to address adverse effects on these resources.

In accordance with National Park Service policies and procedures, the park would continue to protect cultural resources to the greatest extent allowable under present funding and staffing levels. Disturbance of significant cultural resources would be avoided wherever possible, but in instances where avoidance or preservation could not be achieved, appropriate mitigation would be carried out under provisions of the 1999 Programmatic Agreement.

Social Resources

Scenic Resources

Analysis

Under Alternative 1, existing utility infrastructure would be maintained and operated. Since the Merced River and adjacent meadows are included in the A scenic category, and most of the east Valley area is within the A or B scenic categories, construction activities are likely to have short-term, adverse effects on scenic resources. The No Action Alternative is not expected to impact landscape character, access to important viewpoints, or visibility of viewpoints. Repair activities could have localized, short-term, minor, adverse impacts on scenic Valley views from various vantage points. Although views of scenic features would not be obstructed, there is a potential for the visual intrusion of construction activities into the view.

Happy Isles. The Happy Isles area is within the A scenic category. The limited repairs proposed under Alternative 1 in this area could result in short-term, local, minor, adverse impacts to Valley views and views of scenic features through the intrusion of construction activities into the views. Alternative 1 would not result in any long-term impact on the scenic resources of Yosemite Valley.

Campgrounds. Areas impacted by repairs in the Campgrounds area are within all three scenic categories. For example, repairs proposed for Upper Pines Campground are within an area classified as category C. However, the replacement of the Merced River crossing from Lower Pines to North Pines Campgrounds would occur within a category A scenic area. Construction activities in this area could have short-term, minor, adverse impacts to Valley views from some popular vantage points, such as Upper Yosemite Fall, Glacier Point, and Columbia Point. Construction activity in this area could also affect views of some scenic features, such as Half Dome, through intrusion of construction activity into the foreground or intermediate ground view. This would result in a short-term, local, minor to moderate, adverse impacts to scenic resources.

Ecological Restoration Area. The Ecological Restoration area is within the A and B scenic categories. Alternative 1 construction activities would be visible from some popular vantage points and could have short-term, adverse effects on Valley views and views of some scenic features, as discussed above. These impacts would be local, minor to moderate and adverse, but short-term in duration.

The Ahwahnee. The Ahwahnee area is primarily classified as an A scenic area. Construction in this area could be visible from some popular vantage points and could have adverse effects on views of some scenic features through intrusion of construction activity into the view. This would result in short-term, local, minor to moderate, adverse impacts to scenic resources.

Curry Village. The Alternative 1 utility repair activities in the Curry Village area would occur within areas classified as B scenic resources. Construction activities in this area could impact some Valley views in the short-term and would result in local, short-term, minor, adverse impacts.

Housekeeping Camp. Repairs in the Housekeeping Camp area would occur within both A and B scenic areas. Construction activities in this area would be visible from some popular vantage points and could have adverse effects on views of some scenic features through intrusion of construction activity into the view. This would result in short-term, local, minor to moderate, adverse impacts to scenic resources.

Yosemite Village. Repairs in the Yosemite Village area would occur within areas designated as B for scenic resources. Construction in this area could also be visible from some popular vantage points and could have adverse effects on views of some scenic features through intrusion of construction activity into the view. This would result in short-term, local, minor, adverse impacts to scenic resources.

Camp 6/Cook’s Meadow. Repairs in the Camp 6/Cook’s Meadow area would occur primarily within an A scenic category. Construction in this area could be visible from some popular vantage points and could have adverse effects on views of some scenic features through intrusion of construction activity into the view. This would result in short-term, local, minor to moderate, adverse impacts to scenic resources.

Summary of Alternative 1 Impacts

The No Action Alternative would result in a local, short-term, minor to moderate, adverse impacts to highly valued scenic resources. Alternative 1 would not result in any long-term, adverse impact to scenic resources.

Cumulative Impacts

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

Scenic resources have been affected by numerous past actions since the inception of the park. Primary among these is the alteration of natural communities caused by Euro-American settlers who lived in the park. For example, 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-leaved trees along the riverbanks were replaced by the comparatively dense stands of conifers that exist today. These events have resulted in a local, long-term, adverse effect on scenic resources, as the conifers now block views of visually important landscape features that were visible throughout the Valley before the vegetation patterns were changed.

Reasonably foreseeable future actions that would have a net beneficial cumulative effect on scenic resources include those that improve the general health of ecosystems along the Merced River corridor and within Yosemite Valley. The Merced River Plan prescribes the restoration of degraded areas of the Merced River corridor, resulting in beneficial impacts on A category scenic resources, and implementation of the Yosemite Valley Plan would restore riverside meadow areas and result in a net decrease in development within Yosemite Valley. These projects are expected to have a long-term, major, beneficial effect on the scenic resources in Yosemite Valley.

Reasonably foreseeable projects that would have an adverse effect on scenic resources include those Yosemite Valley Plan projects that would result in additional structures and infrastructure within the Valley, including Curry Village Employee Housing, Curry Village and East Yosemite Valley Campground Improvements, and Yosemite Lodge Area Redevelopment. The local, long-term, moderate, adverse effects of these reasonably foreseeable projects would be related to an increase in the amount of development visible in Valley views from popular vantage points, and the potential intrusion of new development areas into views of scenic resources within the Valley. For example, new development at Curry Village could increase the development density in the vicinity of the river and reduce the vegetative screening of the existing Curry Village complex.

The cumulative projects within the Valley would result in a local, long-term, major, beneficial cumulative impact on scenic resources in Yosemite Valley because of the overall emphasis on restoring disturbed or developed land to natural conditions within A category scenic areas and improving the health of ecosystems within Yosemite Valley.

Alternative 1 and the cumulative projects within and in the Merced River corridor would result in a local, long-term, major, beneficial impact on scenic resources in Yosemite Valley. This is due to the overall emphasis on restoring disturbed or developed land to natural conditions and improving the health of ecosystems within Yosemite Valley. The long-term, beneficial effects on highly valued scenic resources associated with the restoration projects proposed in the Yosemite Valley Plan would outweigh the short-term, adverse effects associated with construction activities associated with Alternative 1.

Impairment

The No Action Alternative would result in short-term, minor to moderate, adverse impacts to scenic resources within Yosemite Valley. No long-term impacts to scenic resources are anticipated, and the park’s highly valued scenic resources would not be impaired for future generations.

Visitor Experience and Recreation

Analysis

Alternative 1 would not be expected to result in any long-term effects to visitor experience or recreational resources in Yosemite Valley. Access to park facilities and recreation areas for hiking, swimming, fishing, and other activities may be impacted during construction activities related to utility repairs. Sightseeing by car or bus could be affected by temporary changes in traffic circulation and access. Passive recreation activities could also be disrupted by the noise and visual intrusion of construction activities. Enjoyment of the park at night could be affected by construction lighting, if required. A Visitor Communication and Protection Plan will be developed prior to each utility repair project to ensure that visitors are safely and efficiently routed around construction areas in the Valley. This plan will include means for communicating construction and closure schedules to the public, adequate barriers to keep visitors clear of active construction areas, and clear signage to direct visitors to open park destinations during construction. Construction activities would be expected to have a local, short-term, minor to moderate, adverse effect on visitor experience and recreation near construction sites.

Happy Isles. Construction in the Happy Isles area may result in some short-term road and trail closures on the west side of the Merced River. Activities in this area would not be expected to result in limiting access to the main trails accessed on the east side of the Merced River, but the recreational experience on portions of this trail could be adversely affected by noise and other construction impacts during repairs. Short-term road closures of Happy Isles Loop Road, if required, could impact access by vehicle to this area; however, access to this area by personal vehicle is restricted during normal park operations. No construction activities are expected to occur at night in this area. Overall, construction activities in this area would have local, short-term, minor, adverse effects on visitor experience and recreation.

Campgrounds. Reconstruction of the wastewater line crossing of the Merced River in the Campgrounds area would result in temporary adverse, local effects on the recreation experience in the Lower Pines and North Pines Campgrounds and adjacent areas. This river crossing repair would be constructed during the fall low water, when visitor numbers are lower than during spring and summer.

Construction activities in these areas could have short-term, adverse effects on camping, hiking, and sightseeing experiences for visitors. Major roadways would not be affected, and there would be limited impacts on visitor sightseeing by car or bus. No construction activity would be scheduled to occur at night while these campground areas are open. Construction activities in this area are expected to have local, short-term, minor to moderate, adverse effects on visitor experience and recreation.

Ecological Restoration Area. The Ecological Restoration area also requires reconstruction of a wastewater line crossing of the Merced River east of Stoneman Bridge as well as repairs to facilities paralleling the main roadway between Lower River and Upper River Campgrounds. Construction activities in this area could result in some temporary changes in roadway access or circulation, resulting in adverse, local effects on the recreation experience for visitors within the nearby campground areas and for sightseers traveling by bus or car. The river crossing would be constructed during the fall low water, when visitor numbers are lower than during spring and summer. Construction would not be expected to occur during evening hours. Construction activities in this area are expected to have local, short-term, minor to moderate, adverse effects on visitor experience and recreation.

The Ahwahnee. Construction activity in The Ahwahnee area is not expected to result in changes to traffic circulation or restricted access to park facilities, and is not expected to adversely affect those sightseeing by car or bus. No construction would be scheduled to occur during nighttime hours in this area. Construction in the vicinity of The Ahwahnee and in Ahwahnee Meadow would be expected to have short-term, adverse impacts on visitor trip quality for those visitors staying at The Ahwahnee or spending time in that vicinity. Construction activities in this area are expected to have local, short-term, minor to moderate, adverse effects on visitor experience and recreation.

Curry Village. The repair activities in Curry Village could result in some short-term access restrictions or the rerouting of access to various facilities within Curry Village. No construction would be scheduled to occur during nighttime hours in this area. There could be construction-related noise, odor, and other adverse impacts on recreation experiences for visitors staying in or visiting the Curry Village area during the time required to complete the repairs. Construction activities in this area are expected to have local, short-term, minor to moderate, adverse effects on visitor experience and recreation.

Housekeeping Camp. Repairs in the Housekeeping Camp area would include reconstruction of the Merced River wastewater crossing in this area, which would be constructed during fall low water. These repairs would not be expected to affect major roadways or access to park facilities by visitors traveling by car or bus. No construction would be scheduled to occur during nighttime hours in this area. Construction of utility repairs within Housekeeping Camp could result in local, short-term, minor to moderate, adverse impacts to visitor experience and recreation due to noise and other impacts associated with construction activities.

Yosemite Village. Repairs are required throughout Yosemite Village and would likely result in temporary access restrictions and temporary changes in traffic circulation within Yosemite Village and on Northside Drive. No construction would be scheduled to occur during nighttime hours in this area. Noise and other construction impacts would be expected to result in local, short-term, minor to moderate, adverse effects on visitor experience and recreation in this area.

Camp 6/Cook’s Meadow. Construction activities in this area could result in short-term restrictions on traffic circulation as repairs are constructed near Sentinel Drive. No construction would be scheduled to occur during nighttime hours in this area. Noise and other construction impacts would be expected to result in local, short-term, minor to moderate, adverse effects on visitor experience and recreation in this area.

Summary of Alternative 1 Impacts

Alternative 1 would result in temporary impacts during construction of utility repairs. These activities would result in local, short-term, minor to moderate, adverse impacts on recreation and the quality of visitor experiences near construction sites. Alternative 1 would not result in any long-term, adverse effects on recreational resources or visitor experiences.

Cumulative Impacts

Cumulative impacts on recreation are determined based on analysis of past, present, and reasonably foreseeable future actions in Yosemite Valley in combination with potential effects of this alternative. The projects identified include only those that could affect recreation in Yosemite Valley.

Examples of reasonably foreseeable future actions that could have a beneficial cumulative effect on recreational opportunities include projects proposed under the Yosemite Valley Plan, such as development of a new visitor center in Yosemite Village, expanded transit service distributing visitors to more park destinations, and expansion of campgrounds in Yosemite Valley. Other reasonably foreseeable projects that could have a beneficial cumulative effect on recreation include the following: Happy Isles to Vernal Fall Trail Reconstruction, Discovery View Scenic Overlook Vault Toilet Installation, Rehabilitate Yosemite Valley Campground Restrooms, Eagle Creek Merced River Ecological Restoration (Yosemite Valley), Lower Yosemite Fall Project, and the Shuttle Bus Replacement Project. These projects could result in short-term disruptions of recreational activities due to construction, but in the long term they would provide expanded recreational opportunities in Yosemite Valley and improved transit service distributing visitors to more park destinations.

The Merced River Plan would have a beneficial cumulative effect on recreation in Yosemite Valley by protecting and enhancing a spectrum of recreational opportunities available in the Valley. In addition, the management zoning prescribed under the Merced River Plan provides for various types of recreation, from opportunities for solitude to interactive and group-based recreational activities.

The cumulative projects would have a local, long-term, moderate, beneficial effect on recreation due to expanded recreational opportunities in Yosemite Valley and improved transit service distributing visitors to more park destinations.

Alternative 1 and the cumulative projects in Yosemite Valley would result in a local, long-term, moderate, beneficial impact on recreation due to expanded recreational opportunities in Yosemite Valley and improved transit service distributing visitors to more park destinations. The short-term, minor to moderate, adverse impacts on recreation activities near construction areas would be offset by the beneficial impacts of the cumulative projects.

Conclusions

Alternative 1 would result in local, short-term, minor to moderate, adverse impacts to recreational activities in the vicinity of utility repair projects. No long-term, adverse impacts on recreational resources or visitor experiences are expected.

Impairment

The No Action Alternative would result in local, short-term, minor to moderate, adverse impacts on recreation near construction activities. This alternative is not expected to impact the diversity or quality of recreational opportunities in Yosemite Valley for the long term. Therefore, Alternative 1 would not impair the park’s recreational resources for future generations.

Park Operations and Facilities

Transportation

Analysis. Alternative 1 would not result in any long-term effects on roadways, traffic volume and circulation, and traffic safety. Construction activities would result in temporary increases in construction traffic on access roadways related to worker and material transport to construction sites. Construction of some repairs could result in short-term changes to traffic circulation and result in traffic delays in the vicinity of construction activities. As mentioned previously, a Visitor Communication and Protection Plan will be developed prior to each utility repair project to ensure that visitors are safely and efficiently routed around construction areas in the Yosemite Valley. This plan will include means for communicating construction and closure schedules to the public, adequate barriers to keep visitors clear of active construction areas, and clear signage to direct visitors to temporary changes in traffic patterns during construction. Alternative 1 is expected to have local, short-term, adverse impacts on traffic volume, circulation, and safety related to construction activities.

Happy Isles. The limited repairs that would occur in the Happy Isles area are in an area with little public traffic and are not expected to impact traffic volumes, circulation, or other major roadways in Yosemite Valley.

Campgrounds. The repairs proposed for the Campgrounds area could temporarily affect access roads within the campgrounds, but would not impact other transportation facilities. Alternative 1 would have a local, short-term, negligible effect on traffic circulation and safety in Yosemite Valley.

Ecological Restoration Area. Repairs in this area would occur near Stoneman Bridge and Northside Drive. These repairs could result in some short-term, local, minor to moderate, adverse effects to traffic circulation.

The Ahwahnee. Repairs in The Ahwahnee area could include one crossing of Ahwahnee Road and could result in short-term impacts on this roadway. Therefore, Alternative 1 is expected to have a local, short-term, minor to moderate, adverse impact on traffic circulation and safety from construction in this area.

Curry Village. Curry Village utility repairs could result in some short-term, local, minor, adverse effects to traffic circulation and safety due to repairs required near major roadways in the Curry Village area.

Housekeeping Camp. Repairs within Housekeeping Camp could have short-term, adverse effects on the interior access road in this area but would not affect any major roadways or other transportation facilities. Therefore, Alternative 1 is expected to have a local, short-term, negligible effect on traffic in this area.

Yosemite Village. The extensive repairs required in this area would be expected to require several short-term changes in traffic circulation and access. This is expected to result in local, short-term, minor to moderate, adverse effects on traffic circulation and safety in Yosemite Village.

Camp 6/Cook’s Meadow. Repairs in the Camp 6/Cook’s Meadow area could result in short-term impacts to major roadways where repairs are proposed, including Sentinel Drive, Northside Drive, and Village Drive. This could result in short-term, local, moderate, adverse impacts on traffic circulation and safety in Yosemite Valley.

Summary of Alternative 1 Impacts. Alternative 1 would result in short-term, local, minor to moderate, adverse effects on transportation circulation and safety within Yosemite Valley. These impacts could be minimized and mitigated through development of a Visitor Communication and Protection Plan prior to start of construction.

Cumulative Impacts. Cumulative effects on transportation facilities, traffic circulation, and safety are based on analysis of past, present, and reasonably foreseeable future actions in Yosemite Valley in combination with the potential effects of this alternative. The extent to which past, present, or reasonably foreseeable future projects could have a cumulative effect, when combined with this alternative, is determined largely by whether such projects would affect transportation facilities or traffic circulation within Yosemite Valley.

Past, present, and reasonably foreseeable projects that could have a long-term beneficial effect on transportation include implementation of the Yosemite Valley Plan and YARTS. Since 1950 the population of California has tripled, and the rate of increase in vehicle-miles-traveled has increased six-fold. Transportation conditions within the park have been influenced by this surge in population growth. 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 until the traffic volume and parking demand in Yosemite Valley decrease sufficiently (as visitors leave the Valley) to stabilize traffic conditions, resulting in a long-term, major, beneficial impact to traffic flow on El Portal Road and Big Oak Flat Road.

The Yosemite Valley Plan proposes to enhance the quality of the visitor experience in Yosemite Valley by reducing automobile congestion and limiting crowding. It also proposes traffic management systems and options for the sizing and placement of parking lots, both within and outside of Yosemite Valley. Parking lot(s) outside the Valley could be used to intercept day visitors and shift those visitors to Valley-bound shuttle buses. Implementation of the Yosemite Valley Plan would result in a substantial decrease in traffic volumes and a major improvement in traffic flow within Yosemite Valley and particularly on El Portal Road between its intersection with Big Oak Flat Road and Pohono Bridge. Therefore, the Yosemite Valley Plan would result in a local, long-term, major, beneficial impact to traffic flow, access and circulation, and transportation safety conditions along the Merced River corridor and in Yosemite Valley.

Construction of some of the reasonably foreseeable future projects planned or approved within the Merced River corridor, such as the Curry Village Employee Housing, Lower Yosemite Fall Project, and Yosemite Lodge Area Redevelopment projects, could result in short-term, adverse impacts on transportation. The adverse effects of these projects would be localized and short-term in nature, and primarily related to construction-generated traffic on roadways serving the project sites. Construction activities would increase traffic on local roadways, both from equipment and material haul trips and commute trips by construction workers. Some construction projects could also result in trip delays. The intensity of the adverse effects from the construction-related traffic would range from minor to moderate, depending on which, if any, of the construction projects occurred simultaneously. Activities related to the construction of the reasonably foreseeable projects would result in a local, short-term, minor to moderate, adverse impact to traffic flow.

Collectively, the cumulative projects discussed above would have a local, long-term, major, beneficial impact on transportation conditions along the Merced River corridor. Construction activities associated with the development of cumulative projects, however, would reduce the intensity of this beneficial impact to a minor or moderate level in the short term. Alternative 1 and the cumulative projects would result in a local, long-term, moderate, beneficial impact on transportation conditions along the Merced River corridor.

Conclusions. Alternative 1 would result in local, short-term, minor to moderate, adverse impacts to traffic circulation and safety. No long-term adverse impacts on traffic circulation or safety are expected.

Impairment. The National Park Service has a management responsibility to conserve the scenery, natural and historic objects, and wildlife resources of the park. Traffic operations are not subject to the impairment standard.

Park Operations

Analysis. Under Alternative 1, existing utility facilities would remain in place and be maintained and repaired. Major repairs are required on wastewater collection facilities throughout the Valley, and other utilities will require repairs over time. Park operations staff would continue to operate, maintain, and repair utility systems as needed. Costs associated with operating and maintaining these facilities could increase over time, particularly due to the effort required to maintain numerous utility river crossings. The effect on park operations from increased efforts and costs is considered to be moderate. Impacts on park operations are not expected to vary by area, and therefore are not discussed for each area individually.

Summary of Alternative 1 Impacts. Alternative 1 would have local, long-term, moderate, adverse impacts on park operations.

Cumulative Impacts. Cumulative effects on park operations and facilities are based on analysis of past, present, and reasonably foreseeable future actions in Yosemite Valley in combination with potential effects of this alternative. The extent to which past, present, or reasonably foreseeable future projects could have a cumulative effect, when combined with this alternative, is determined largely by whether such projects would affect park facilities or the demand for park operations services and facilities. Projects that affect park facilities themselves or the demand for facilities management, resource management, and maintenance of utility systems services in particular would have the potential for cumulative effects with the proposed project.

Park operations and facilities have been affected by numerous past National Park Service management decisions and projects since the inception of the park. Recent projects include Cook’s Meadow Ecological Restoration, Happy Isles Gauging Station Bridge Removal, the Merced River Plan, and implementation of the Yosemite Valley Plan. Overall, there is no net adverse or beneficial effect of these past actions on park operations and facilities.

Reasonably foreseeable future actions that would have a beneficial cumulative effect on park operations and facilities are 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. An example is the Replacement/Rehabilitation of the Yosemite Valley Main Sewer Line. Although this project would have short-term, adverse effects associated with planning, construction, replacement, and rehabilitation, its overall effect would be to reduce long-term maintenance. Therefore, this project would have a long-term, beneficial cumulative impact on park operations and facilities.

Examples of reasonably foreseeable projects that would have an adverse effect on park operations and facilities are the Merced River Plan and the Yosemite Valley Plan. Implementation of these plans would 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, and restoration of large areas of Yosemite Valley to natural conditions). Implementation of these plans is expected to have local, short- and long-term, moderate to major, adverse impacts on park operations and facilities.

Overall, the past, present, and reasonably foreseeable future actions would have local, moderate, adverse cumulative impacts because of the increased demand on park operations, services, and facilities over both the short and long term. These cumulative effects, in combination with Alternative 1, would result in local, short- and long-term, moderate to major, adverse impacts on park operations and facilities.

Conclusions. Alternative 1 would result in local, long-term, moderate, adverse impacts on park operations and facilities related to costs for operation and maintenance of dispersed utility facilities with a high number of river and creek crossings.

Impairment. The National Park Service has a management responsibility to conserve the scenery, natural and historic objects, and wildlife resources of the park. Park operations are not subject to the impairment standard.

Socioeconomics

Analysis

Alternative 1 would continue the ongoing management and operation of existing utility systems within Yosemite Valley. Alternative 1 would result in the continuation of routine operations, including maintenance of utility facilities and repairs, as needed. It also includes conducting those repairs required to comply with the California Regional Water Quality Control Board Cleanup and Abatement Order. Since the socioeconomic effects are not related to specific subareas within the Valley, these effects are not discussed by area.

Alternative 1 would result in $11.4 million in direct spending on materials, labor, and equipment for emergency, immediate, and intermediate repairs required to ensure compliance of the existing wastewater system with the Cleanup and Abatement Order. Not all of this cost would be spent within the regional economy. Typically, design and engineering costs are spent outside of the region and can account for up to 25% of the total estimated project cost. In addition, a significant portion of construction costs also may be spent outside the region. It was estimated that approximately 50% of the total $11.4 million would be spent within the three-county region of Mariposa, Tuolumne, and Madera Counties.

In addition to the expected $5.7 million in direct expenditures within the region, the construction expenditures would result in secondary and induced effects within the economy as the construction dollars are spent by businesses and households. Secondary and induced impacts were estimated using economic multipliers developed by the Department of Commerce, Bureau of Economic Analysis (CCTF 2002). Based on these multipliers, $5.7 million in construction expenditures would result in $13.4 million of economic output in the region, including $4.3 million in earnings to households and creation of 123 jobs in the regional economy. Based on 2000 economic data presented in Chapter III, the changes in economic output and employment would represent an increase of 0.2% over existing conditions and would likely not have a discernible effect on the social and economic environment. Therefore, construction expenditures related to this alternative would have a regional, short-term negligible, beneficial impact on the economy.

Summary of Alternative 1 Impacts

Alternative 1 would result in a regional, short-term, negligible, beneficial impact on the region’s economy but could reduce regional, long-term benefits by adversely affecting development proposed under the Yosemite Valley Plan.

Cumulative Impacts

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

Reasonably foreseeable future projects by the National Park Service that could have a beneficial cumulative effect on the regional economy are related to construction activity, including the Curry Village Employee Housing, Eagle Creek Merced River Ecological Restoration, Ecological Restoration of Flood-Damaged Campgrounds, the El Portal Road Improvement Project (from Cascades Diversion Dam to Pohono Bridge), Cascades Dam Removal, Happy Isles Fen Habitat Reclamation Project, Happy Isles Gauging Station Bridge Removal, Happy Isles to Vernal Falls Trail Reconstruction, Curry Village and East Yosemite Valley Campground Improvements, Lower Yosemite Fall Project, Replacement/Rehabilitation of Yosemite Valley Main Sewer Line, Yosemite Lodge Area Redevelopment, and Yosemite Valley Shuttle Bus Stop Improvements. Private development projects such as the Yosemite Motels Expansion just outside of the park entrance at El Portal and other facilities constructed under the Mariposa County General Plan Update would also result in short-term spending in the construction sector.

The cumulative planning, transportation, facility improvement, and development-related projects identified would generate construction-related output, employment, and income in the regional economy. Construction spending associated with the cumulative projects would also generate secondary output impacts as a result of local spending on materials and wages. Some of this construction-related spending would be expected to occur outside of the affected region.

The total construction-related spending in the affected region associated with the cumulative projects would have a short-term, major, beneficial impact on the regional economy resulting from the substantial and highly noticeable increase in construction output, income, and employment in the three-county region. The increase in construction-related output would be highly noticeable when compared with the total output of the construction industry in the affected region.

Some projects would increase the amount of visitor overnight accommodations in or near the park, including the Curry Village and East Yosemite Valley Campground Improvements, Yosemite Lodge Area Redevelopment, and Yosemite Motels Expansion. Increased overnight accommodations from these projects would result in a beneficial impact to employment, output, and taxable retail sales over the long term. The effect of this increase would be negligible because the total increase in overnight accommodations would not be substantial in comparison to existing accommodations. Therefore, cumulative actions would result in a local, long-term, negligible, beneficial impact to the regional economy.

The cumulative projects within and in the vicinity of Yosemite National Park would result in a local, long-term, negligible, beneficial impact to the regional economy, and a local, short-term, major, beneficial impact during construction. While Alternative 1 would have a local, short-term, negligible benefit on the regional economy, Alternative 1 could also adversely affect the full implementation of many of the projects proposed under the Yosemite Valley Plan, due to a lack of utility infrastructure capable of efficiently serving redeveloped or new proposed areas. These adverse effects could result in a reduction of the long-term, negligible, beneficial impact expected from the cumulative projects.

Impairment

The National Park Service has a management responsibility to conserve the scenery, natural and historic objects, and wildlife resources of the park. Socioeconomic resources are not subject to the impairment standard.

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