Chapter IV: Environmental Consequences

Introduction

This chapter describes the probable consequences (or impacts) that could result under the alternatives described in this environmental assessment. The chapter is divided into three parts. The Introduction describes the methodologies and assumptions that are common to all resource topic areas. The Methodologies and Assumptions section presents the methods used to assess impacts for each specific resource topic. The next section describes the impacts anticipated under each alternative, organized by resource topic. Environmental impacts are summarized in Chapter II, table II-1: Summary of Environmental Consequences.

Impact Analysis

Each alternative contains an impact analysis for each individual resource topic. Impacts are evaluated based on context, duration, and intensity 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 (NPS 1997).

§         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 the immediate vicinity of the Curry Village and East Yosemite Valley Campground Improvements Project, unless otherwise noted.

§         Duration. The duration of an impact is noted as either short term or long term and is 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 mitigation measures have already been implemented.

Alternative 1 (the No Action Alternative) describes the continuation of current management actions in Yosemite Valley and the project area. This alternative would continue to provide ongoing repairs and maintenance of existing project area utilities. 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 Council on Environmental Quality 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. The list of cumulative projects included in this analysis is provided in Appendix D.

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 of 1916. The Organic Act established the National Park Service with a mandate “to conserve the scenery and the natural and historic objects and the wildlife 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 is less likely to constitute impairment if it is an unavoidable result, which cannot reasonably be further mitigated, of an action necessary to preserve or restore the integrity of park resources or values (NPS 2000a). An impact is more likely to constitute impairment to the extent that it affects a resource or value whose conservation is:

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

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

§         Identified as a goal in the park’s General Management Plan (NPS 1980) 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 not automatically. Rather, these impacts must be analyzed with respect to the three bulleted criteria above. Impairment is generally considered for recreation and for geologic, hydrological, biological, cultural, and scenic resources. Impairment is addressed in the conclusion section of each impact topic under each alternative.

Methodologies and Assumptions

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

Geologic Processes

This document focuses on potential damage from geologic processes such as earthquakes and rockfalls. The U.S. Geological Survey conducted mapping in Yosemite Valley to determine the location of the base of the talus, and the location of the rockfall zone (the distance calculated to determine outlying boulder locations beyond the extent of the talus). Geologic processes can negatively affect visitors, personnel, and facilities when events such as rockfalls, earthquakes, and severe soil instability result in injury, death, or damage to facilities. ^[1]

Based on active fault locations and rockfall susceptibility, several assumptions regarding facility placement, geologic design parameters, and public safety were integrated into this assessment, as summarized below.

§         It is not possible to avoid risks due to geologic processes such as earthquakes and rockfalls. Considering this, some facilities located within the project area could be exposed to the risk of damage from earthquakes and rockfalls.

§         Geotechnical studies to determine soil stability conditions would be performed prior to placing, designing, or relocating a facility within the project area, and facility design within the project area would conform to accepted building codes regarding seismic design parameters.

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

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

§         Large-impact, low-frequency geologic hazards that affect public safety are rarely predictable, and the extent to which they may affect people and property cannot be quantified. Analysis of such effects is therefore qualitative, and professional judgment is applied to reach reasonable conclusions as to the context, duration, and intensity of potential impacts.

§         Low- to moderate-impact, high-frequency geologic hazards can be forecast and appropriate geotechnical and structural engineering design can reduce the risk to public safety. Seismically induced rockfall can only be mitigated by avoiding development in hazard zones.

Duration of Impact

Geologic impacts related to seismic events would likely be long term and permanent.

Intensity of Impact

The intensity of an impact is based on its location within the project area and on the types of activities and facilities proposed in that location. The intensity of the impact would be negligible if facilities of any kind are located outside geologic hazard zones. The intensity of the impact would be minor if standard-occupancy and miscellaneous facilities are located within the rockfall zone. The intensity of the impact would be moderate if essential, hazardous, or special occupancy facilities are located within the rockfall zone.

There will always be a potential for adverse impacts to life and property due to seismic hazards, especially in developed areas. Therefore, management actions to avoid placement of facilities in areas susceptible to seismic hazards may decrease the risks, but would not necessarily reduce the intensity of the impact.

Type of Impact

All seismic events are potentially hazardous. The type of impact is related to risk, and it is difficult to estimate risk involving natural events. In general, reducing risk is considered a beneficial impact. The impact is considered beneficial if there would be a decrease in the density of individuals or facilities within the rockfall zone.

Generally, maintaining facilities within or moving facilities into a zone of higher risk or exposing people to greater levels of risk is considered adverse. Specifically, the impact is considered adverse if essential and hazardous occupancy facilities remain in or are placed in the rockfall zone.

Soils

This document analyzes impacts to soils in undeveloped natural zones. The soils data used were gathered from the park’s geographic information system. Actions prescribed in the Curry Village and East Yosemite Valley Campground Improvements Project could affect soil resources through erosion, compaction, soil profile mixing, and soil removal. Activities that could result in soil impacts include the construction of buildings, campsites, parking areas, roads, trails, other facilities, and utilities.

§         Soil Erosion. Removal of vegetation through grading activities or pedestrian use could accelerate erosion of the soil surface. Soils on steep slopes and along watercourses are especially susceptible to erosion.

§         Soil Compaction. Soil compaction could 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 Profile Mixing. Soil excavation and redistribution result in removal or mixing of the soil profile and disrupt 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 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 have taken thousands of years to develop. Covering the surface reduces water movement and interferes with normal physical and chemical processes.

Duration of Impact

Short-term soils impacts could be restored when project construction is completed and were considered to last 20 years or less. Long-term impacts are those that would last for over 20 years.

Intensity of Impact

The evaluation of the intensity of impacts on soils focuses on resilient soils and other soils. Resilient soils are more capable of withstanding alteration without permanent deformation. These soils tend to recover more quickly from alteration. Generally, resilient soils do not have major use limitations or severely restricted physical attributes.

Soils classified as other soils generally 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.

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

Table IV‑1 Soil Impact Intensity Definitions
Soil Type	History of Disturbance	Size of Impact
		Small Scale (1 to 5 acres)	Small but Measurable (5 to 10 acres)	Measurable and Moderate Scale (10 to 20 acres)	Large Scale (>20 acres)
Resilient Soils	Previously Disturbed	Negligible	Negligible	Minor	Moderate
	Undisturbed	Negligible	Minor	Moderate	Moderate
Other Soils	Previously Disturbed	Negligible	Minor	Moderate	Moderate
	Undisturbed	Minor	Moderate	Moderate	Major

Source: EDAW 2003

 Hydrology and Water Quality

Hydrology refers to hydrologic processes such as flooding, erosion, deposition, and 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).

 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 (NPS 1991a) 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 federal, state, interstate, and local requirements, administrative authority, and sanctions with respect to the control and abatement of water pollution.

Duration of Impact

Short-term impacts are those that occur during project implementation and are usually considered to last for less than two years (e.g., construction projects). Long-term impacts are those that would remain after the alternative has been implemented and usually last longer than two years. Since full project implementation 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, construction of new structures) instead of full project implementation.

Intensity of Impact

Negligible impacts would be imperceptible or not detectible. 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 could be permanent.

Type of Impact

Adverse impacts would alter natural hydrologic conditions (e.g., impede flood flow, 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 would restore natural hydrologic conditions (e.g., remove impediments to flood flow, 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 in this section 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, Floodplain Management, and the National Park Service Special Directive 93-4, Floodplain Management Guideline (NPS 1993a). 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. The extent of floodplain impact established by the 1997 flood inundation was considered for this project.

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 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. In this case, a statement of findings must be written to document a decision to place facilities within a floodplain.

 Duration of Impact

Short-term impacts are those that would occur over a period of less than one year. Long-term impacts are those that would occur for more than one year.

Intensity of Impact

Beneficial and adverse impacts of individual actions in each alternative were assigned intensities as they relate to effects on the safety of humans and property in the floodplains. In the context of risk to human life and property, the removal of structures from the designated floodplain is considered a beneficial impact. Development of new Class I or Class II actions (nonexempted facilities) in the 100-year floodplain is considered an adverse impact to human life and property. Definitions of impact intensities are provided in table IV‑2.

 

Table IV‑2 Floodplain Impact Intensity Definitions
Intensity	Presence of people in floodplain	Ease of flood evacuation	Number of structures in floodplain	Flooding damage to property
Negligible	Daytime only (few to none)	Easy	Few to none	No damage likely
Minor	Daytime only (may be numerous)	Easy	Few	Slight damage possible
Moderate	Overnight	Easy	Medium	Severe damage possible
Major	Overnight	Difficult	Numerous	Severe damage likely

Source: EDAW 2003

 Wetlands

The National Park Service is committed to minimizing wetland loss. The wetland protection mechanisms used by 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 Section 404; and the “no net loss” goal outlined by the White House Office on Environmental Policy in 1993. Executive Order 11990 requires that leadership be provided by involved agencies to minimize the destruction, loss, or degradation of wetlands. The National Park Service Director’s Order #77-1 and Procedural Manual #77-1 provide specific procedures for carrying out the executive order. Section 404 of the Clean Water Act requires project applicants to obtain permits from the U.S. Army Corps of Engineers for discharges of fill or dredged materials into waters of the United States. Waters of the U.S. are defined to include navigable rivers and streams, their tributaries, and adjacent or hydrologically connected wetlands.

Wetland impacts were estimated using wetland-specific data collected as part of the Yosemite Valley Plan and wetland delineations conducted in December 2002 and January 2003.

Duration of Impact

Short-term wetlands impacts are those that would last up to 20 years following project implementation; long-term impacts would last for more than 20 years after project implementation.

Intensity of Impact

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

Type of Impact

Adverse impacts are those that 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

Short-term vegetation impacts are those that would last up to 20 years following project implementation; long-term impacts would last for more than 20 years after project implementation.

 Intensity of Impact

Two primary parameters were used to evaluate the intensity of impacts on vegetation: (1) the size and continuity of plant communities; and (2) the nature, structure, diversity (integrity), and rarity of plant communities.

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 (e.g., density, arrangement, and presence or absence of natural vegetation layers), and individual species composition and abundance.

Other not-so-visible impacts (such as encroachment of wetland habitats by non-native species) would continue to be managed by vegetation management staff in conjunction with National Park Service programs that provide for the protection and long-term management of the park’s vegetative resources.

Types of Impact

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

Wildlife

Impacts on wildlife were 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. 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.

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.

Duration of Impact

Short-term wildlife impacts are those that would last for less than 20 years. All short-term impacts to wildlife and habitat resulting from project implementation would be associated with construction activities. These impacts would 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.

§         Removing, trampling, or running over vegetation during temporary use of some habitat as staging areas for machinery or materials could affect wildlife until such areas are restored after the project.

§         Diversion of water flows during construction could 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 are those that would last for 20 years or longer. The impact analysis focused primarily on the long-term effects of implementation during the operational lifetime of the alternatives that would result in changes in the abundance, diversity, and distribution of wildlife.

Intensity of Impact

Negligible impacts are those 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 are 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 are classified as beneficial if they would positively affect the size, continuity, or integrity of wildlife habitat.

Special-Status Species

This analysis includes species listed under the Federal Endangered Species Act as threatened or endangered; species listed by the state of California as threatened, endangered, or species of concern; 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 of habitat; and (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.

The assessment of potential impacts to special-status plant species was based on comparisons between the No Action Alternative and the action alternatives. Impacts were evaluated considering species sensitivity to impacts (based on rarity, resilience, size of population, and extent of species throughout the park); location of species in proximity to new disturbance; and mitigation measures applied as appropriate for the species and the site.

Duration of Impact

Short-term impacts to special-status wildlife and plant species are those that would last for less than 20 years; long-term impacts are those that would last for more than 20 years.

Intensity of Impact

The Federal Endangered Species Act defines the terminology used to assess impacts on listed species. In this document, the terminology used for all special-status species is as follows:

§         No effect – The appropriate conclusion when proposed actions would not affect a special-status species or designated critical habitat.

§         Not likely to adversely affect – The appropriate conclusion when impacts on special-status species are expected to be discountable, insignificant, or completely beneficial. Beneficial impacts are contemporaneous positive effects without any adverse effects on the species. Insignificant impacts relate to the size of the impact and should never reach the scale where incidental take occurs. Discountable impacts are those extremely unlikely to occur.

§         Likely to adversely affect – The appropriate finding if any adverse impact on special-status species may occur as a direct, indirect, interrelated, or interdependent action. In the event the overall impact of the proposed action is beneficial to the special-status species, but is also likely to cause some adverse effects, then the action is “likely to adversely affect” the species. If incidental take is anticipated to occur as a result of the proposed action, a “likely to adversely affect” determination should be made.

§         Likely to jeopardize proposed species / adversely modify proposed critical habitat – The appropriate conclusion when the proposed action is likely to jeopardize the continued existence of a proposed species or adversely modify the proposed critical habitat. This conclusion is also likely to indicate impairment of park resources or values.

Type of Impact

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

Air Quality

This air quality analysis was based on a qualitative analysis of air emissions from construction and removal activities as well as long-term operations of facilities. 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.

The air quality assessment involved the identification and qualitative description of the types of activities associated with the Curry Village and East Yosemite Campground Improvements Project that could affect air quality, corresponding emissions sources and pollutants. A qualitative assessment was performed to determine the potential for higher pollutant emissions or concentrations, taking into account the frequency, duration, location, and reversibility of the potential impact. 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 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 measures 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 impacts 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

Short-term air quality impacts are those that would be associated with construction and removal activities, while long-term impacts are those that would result from changes in motor-vehicle-related emissions.

Intensity of Impact

Negligible impacts are those that would be barely perceptible and confined to a small area. Minor impacts would be perceptible and remain localized and confined. Moderate impacts would be sufficient to cause a change in the air quality. Major impacts would result in substantial and highly noticeable changes in air quality.

Type of Impact

Beneficial air quality impacts are those that would reduce emissions or lower pollutant concentrations, while adverse impacts would increase emissions or raise pollutant concentrations.

Noise

Noise impacts could result from either transportation-related actions or from nontransportation actions. Noise impacts related to the project alternatives are expected to be limited to construction-related activities and nontransportation actions. The number of vehicles traveling through the project area is not anticipated to substantially change over existing conditions, although the mix of vehicles could change. A qualitative assessment of noise impacts is presented. The action alternatives are assessed relative to the No Action Alternative. The following types of noise associated with an activity or facility have been evaluated:

§         Construction/demolition (voices, heavy equipment, tools, forestry, etc.)

§         Housing (voices, service vehicles, trash removal, music, dogs, etc.)

§         National Park Service and primary operations (voices, service vehicles, sirens, idling vehicles, fueling stations, snow removal, trash removal, etc.)

§         Parking (voices, service vehicles, trash removal, etc.)

§         Lodging (voices, service vehicles, trash removal, etc.)

§         Pedestrian and hiking trails (voices, etc.)

In addition, the following assumptions were used:

§         There are two types of sensitive receptors with respect to nonvehicle noise: visitors and residents. Sound is considered a noise impact only if it is experienced by a sensitive receptor.

§         A reduction in the number of people (e.g., visitors, employees, or residents) in an area would generally result in a reduction in the amount of noise (fewer voices, fewer service vehicles, less trash removal, etc.), but not necessarily a reduction in peak noise levels.

§         An increase in the number of people (e.g., visitors, employees, or residents) in an area would generally result in an increase in the amount of noise (more voices, more service vehicles, more trash removal, etc.), but not necessarily an increase in peak noise levels.

§         A reduction in facilities (e.g., buildings, cabins, parking areas, etc.) in an area would generally result in a reduction in the amount of noise (fewer voices, less heavy equipment, less trash removal, etc.), but a reduction in peak noise levels would be a function of which facilities were removed.

§         An increase in facilities (e.g., buildings, cabins, parking areas, etc.) in an area would generally result in an increase in the amount of noise (more voices, more heavy equipment, more trash removal, etc.), but the peak noises produced would be a function of the types of facilities introduced.

Duration of Impact

Short-term noise impacts are those that would be temporary in duration and would be associated with construction. Long-term impacts have a permanent effect on the ambient noise environment (visitor and operational activity).

Intensity of Impact

Negligible impacts are those that would not be detectible. Minor impacts would be slightly detectible in close proximity to the source, but are not expected to have an appreciable effect on ambient noise levels. Moderate impacts would be clearly detectible and could have an appreciable effect on ambient noise levels; moderate adverse impacts could include introduction of noise associated with an activity or facility into an area with little or no ambient noise. Major impacts would be clearly audible against ambient noise levels or would have a substantial, highly noticeable effect on ambient noise levels.

Type of Impact

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

Cultural Resources

Section 106 of the National Historic Preservation Act requires a federal agency to take into account the effects of its undertakings on properties included or eligible for inclusion on the National Register of Historic Places and to provide the Advisory Council on Historic Preservation the reasonable opportunity to comment. This requirement applies to properties not formally determined eligible, but which are considered to meet eligibility requirements. A Programmatic Agreement was developed among the National Park Service, the California State Historic Preservation Office, and the Advisory Council on Historic Preservation, in consultation with American Indian tribes and the public, which guides the park’s actions in regards to historic properties.

The methodology for assessing impacts to historic resources is based on Stipulations V through VIII of the Programmatic Agreement. This methodology includes: (1) establishing an area of potential effect; (2) assessing the level of resource information available and conducting appropriate inventories and evaluations necessary to obtain information about resources eligible for listing on the National Register; (3) comparing the location of the impact area with that of resources listed, eligible, or potentially eligible for listing on the National Register of Historic Places; (4) identifying the extent and type of effects; (5) assessing these effects according to procedures established by the Advisory Council on Historic Preservation’s regulations; and (6) considering ways to avoid, reduce, or mitigate adverse effects.

Cultural resource impacts in this environmental assessment are described in terminology consistent with the regulations of the Council on Environmental Quality, and in compliance with the requirements of the National Environmental Policy Act, 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 under the heading “Section 106 Summary” for each alternative, presented later in this chapter.

Duration of Impact

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

Type of Impact

Under the National Environmental Policy Act, impacts to historic properties (cultural resources) are considered to be either adverse or beneficial. For the purposes of assessing effects to historic properties under Section 106 of the National Historic Preservation Act, effects are either adverse or not adverse. Impacts/effects under both the National Environmental Policy Act and the National Historic Preservation Act are considered adverse when they diminish the significant characteristics of a historic property.

Intensity of Impact

Negligible cultural resource impacts are those that would result in barely perceptible changes in the 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 the 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 the 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 of Impacts

The National Environmental Policy Act also calls for a discussion of the appropriateness of mitigation and an analysis of the effectiveness of mitigation. A reduction in the intensity of an impact due to mitigation is an estimate of the effectiveness of the mitigation under the National Environmental Policy Act, but 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, and the National Park Service may satisfy the Section 106 obligation, the effects would still be considered adverse under the National Historic Preservation Act.

Mitigation for National Environmental Policy Act purposes in this document is based on the 1999 Programmatic Agreement and includes the avoidance of adverse impacts or the application of one or more standard mitigation measures 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 (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. Stipulation VIII of the Programmatic Agreement requires the National Park Service to notify the State Historic Preservation Officer, 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 that have an adverse impact on historic properties.

Archeological Resources

Archeological resources are typically considered eligible for inclusion on the National Register of Historic Places under criterion d of 36 Code of Federal Regulations, Part 60, for the information they have or may be likely to yield.

Type and Duration of Impact

Any change to the physical attributes of an archeological site is considered irreparable, adverse, and permanent. Adverse impacts to archeological resources most often occur as a result of earthmoving activities within an archeological site, soil compaction, increased erosion, unauthorized surface collection, or vandalism. Beneficial impacts to archeological resources can occur when ongoing impacts, which would otherwise continue to degrade archeological resources, are reduced or arrested due to changes in visitor-use patterns or management practices in the vicinity of the resources. 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 increased visitor activity or management actions in the vicinity of an archeological site, leading to such occurrences as artifact collection, accelerated soil compaction, or erosion.

Intensity of Impact

The intensity of an 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 could 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 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 sites with high data potential.

Mitigation

For archeological resources, mitigation includes avoiding sites through project design, or recovering information that makes the sites eligible for inclusion on the National Register of Historic Places. According to Stipulation VII (C) of the 1999 Programmatic Agreement, effects on archeological resources are not considered 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).

Ethnographic Resources

Ethnographic resources are considered eligible for inclusion on the National Register of Historic Places as traditional cultural properties when they are rooted in a community’s history, are important in maintaining the continuing cultural identity of the community, and meet criteria for evaluation and integrity. The intensity of impacts to ethnographic resources may relate to access and use of, as well as changes to, traditionally important places.

Type of Impact

Impacts to ethnographic 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 resources are enhanced; or when access for American Indian people is enhanced. Adverse impacts occur when physical changes to a traditionally used resource or its setting degrade the resource itself, or decrease 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, or alter the characteristics for which the resource is eligible for listing on the National Register. They are considered long term if they involve a change in important vegetation or cultural features, add a new facility or increase visitor use in a way that would change the physical character of, or access to a resource for a noticeable period of time, or alter the characteristics for which a resource is eligible for listing on the National Register. This period of time would vary by resource type and traditional practitioners. These long-term changes would disrupt cultural traditions 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 ethnographic 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 an ethnographic resource would depend on the importance of the resource to an ongoing cultural tradition, as well as the extent of the 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 ethnographic landscape). Minor impacts would be perceptible and measurable and would 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 individually significant property.

Mitigation

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

Cultural Landscape Resources, Historic Sites, and Structures

Type of Impact

Impacts to cultural landscape resources and historic sites and structures 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; removing a significant structure or a landscape resource; or adding 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 to 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 changes in the management of resources fostered by the completed action.

Duration of Impact

Impacts to historic structures and cultural landscape resources are considered short term if they involve such activities as temporary road closures, where the impacts are noticeable for a period of one to five years. Other examples of short-term impacts to historic structures include constructing scaffolding around 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 5 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 to an adjacent facility. Permanent impacts to a historic structure or landscape resource 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 would be barely perceptible and not measurable and would be confined to small areas or a single contributing element of a larger National Register district. Minor impacts would be perceptible and measurable, but would 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. The level of this documentation, which includes photography and a narrative history, would depend upon the significance of the resource (national, state, or local) and the nature of the resource (an individually significant structure, or a contributing element in a cultural landscape or historic district). 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 Organic Act of 1916, is to conserve the scenery and natural and historic objects. Following this direction, the impacts on scenic resources were determined by examining the potential effects of the Curry Village and East Yosemite Valley Campground Improvements Project on the landscape character and/or features and how changes would be experienced visually. The visual analysis incorporated the scenic resources methodology applied in the Final Yosemite Valley Plan/Supplemental Environmental Impact Statement (SEIS) (NPS 2000a) and utilizes the National Park Service scenic rating categorizations defined below:

§         A-scenic. Areas included in scenic views commonly chosen by eminent early photographers and painters, or included in the most significant scenery views existing today (includes all meadows and the Merced River).

§         B-scenic. Areas included in scenic views less commonly chosen by historic photographers and painters, or comprising less significant modern views.

§         C-scenic. Areas of minor scenic quality and areas accepting visual intrusion without detracting from either A-scenic or B-scenic views.

Scenic resource 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.

Although views are not a prominent feature of the Curry Village area (NPS 1994c), views of a number of important Valley features are available from the open areas of the Village, including views of Stoneman Meadow, the Valley floor, and surrounding cliffs. Impacts to the following primary views from within Curry Village were considered as part of the scenic resources impact assessment:

§         View of Glacier Point, looking south from the area between the Curry Pavilion to the lounge building

§         View of Half Dome, looking east from the vicinity of the ice rink and Curry Orchard parking lot

§         View of Royal Arches and Washington Column, looking north from the Curry Orchard parking lot

§         View of Stoneman Meadow, looking east from the east end of Boys Town

Duration of Impact

Short-term impacts are those that would be short-lived or temporary due to construction and demolition activities, and long-term impacts would be permanent and continual.

Intensity of Impact

Negligible impacts are those that would be imperceptible or not detectible. Minor impacts would be slightly detectible or localized within a relatively small area. Moderate impacts would be those that are readily apparent and occur within A-scenic or B-scenic areas. Major impacts would be substantial, highly noticeable, and/or result in a change to the character of the landscape in an A-scenic or B-scenic area.

Type of Impact

Beneficial impacts are those that would enhance the existing landscape character. Adverse impacts would reduce the existing landscape character. Impacts to C‑scenic areas are not considered adverse. Impacts to areas categorized as B-scenic or A‑scenic are considered adverse if they would substantially alter the important scenic features associated with that classification.

Park Operations and Facilities

The Curry Village and East Yosemite Valley Campground Improvements Project was analyzed in terms of the utilities or services that would need to be expanded to service new development under each proposed alternative, focusing primarily on the increased number of connections that would be needed. Analysis of effects was qualitative, and professional judgment was applied to reach reasonable conclusions as to the context, duration, and intensity of potential impacts.

Duration of Impact

Short-term impacts are those that would occur during construction activities. Long-term impacts would cause a permanent change in utility operation.

Intensity of Impact

Negligible impacts are those that would not be detectible and would have no discernible impact on water and wastewater flows. Minor impacts to water and wastewater flows would be slightly detectible, but would not be expected to have an overall effect on those conditions. Moderate impacts would be clearly detectible and could have an appreciable effect on water and wastewater flows. Major impacts would have a substantial impact on water and wastewater flows that could permanently alter these conditions.

Type of Impact

Impacts for each alternative were evaluated by qualitatively assessing changes to load and demand, facilities, and infrastructure. For purposes of this analysis, an alternative is assumed to have an impact (adverse or beneficial) on utilities, solid waste, or recycling if it would result in:

§         Direct changes to existing park utilities, operation, facilities, or staffing requirements or policies associated with park utilities or operations

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

The analysis was based on the assumption that connections from existing lines to new facilities would be as direct as possible, while also attempting to avoid impacts to trees, wetlands, and other sensitive resources. Impacts to existing structures, roads, and utilities infrastructure would also be avoided to the extent possible in order to minimize indirect effects. Beneficial impacts would result from decreased service or utilities requirements or increased quality or reliability of utilities or service.

Transportation

The transportation analysis considered the effects of changes to overnight accommodation facilities and access patterns on traffic volumes/circulation and associated traffic flow and safety conditions. It was assumed that visitation patterns would not change substantially from existing conditions, with the exception of day-use visitation, which would be altered by the removal of day-visitor parking from Curry Village. Construction impacts were also evaluated. Qualitative analysis was conducted to assess the effects on traffic flow and traffic safety to reach reasonable conclusions as to the context, intensity, and duration of potential impacts. The analysis was based on information presented in the Final Yosemite Valley Plan/SEIS and also incorporated information from the Yosemite Valley Cultural Landscape Report (NPS 1994c), the Final Yosemite Transportation Alternatives Study (BRW 2000), and the Yosemite Transportation Symposium (NPS 1996). When possible, mitigation measures were incorporated into the alternatives to reduce the intensity of adverse effects.

Duration of Impact

Short-term impacts are those that would occur during construction activities (e.g., temporary disruption of access during construction of facilities). Long-term impacts would cause permanent changes to traffic volumes, as well as changes to circulation (e.g., removal of Southside Drive from Stoneman Meadow) following completion of the construction phase of the alternative.

Intensity of Impact

Negligible impacts are those that would not be detectible and would have no discernible effect on traffic flow and/or traffic safety conditions. Minor impacts on traffic flow and/or traffic safety conditions would be slightly detectible, but not expected to have an overall effect on these conditions. Moderate impacts would be clearly detectible 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

Beneficial impacts are those that 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.

Visitor Experience and Recreation

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

Visitor experience is also directly affected by actions that influence 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 were qualitatively assessed using professional judgment to analyze the effects of the project on the activities of different visitor populations. These conclusions have been considered in combination with existing data on the proportion of visitors who participate in different park activities. Beneficial impacts would enhance visitor participation, the quality of visitor experiences, or service levels.

Duration of Impact

Short-term impacts on the visitor experience are those that would be temporary in duration due to construction or demolition activities. Long-term impacts would have a permanent effect on the visitor experience.

Intensity of Impact

Negligible impacts are those that 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 the number of participants). Major impacts would eliminate or greatly enhance multiple critical characteristics or greatly reduce/increase participation.

Type of Impact

Beneficial impacts are those that would enhance visitor participation, the quality of visitor experiences, and service levels. Adverse impacts would reduce visitor participation, the quality of visitor experiences, and service levels. The analysis was also based on whether there would be a complete loss of a recreational opportunity, a change in access to or availability of a recreational opportunity, or a change in the aggregate of recreational opportunities for the visitor.

Night Sky

Interior and exterior lighting of buildings and of certain infrastructure such as parking facilities is needed to accommodate visitors. This lighting has the potential to affect the ability to see the night sky and landscape. The Yosemite National Park Exterior Lighting Guidelines (NPS 1997d) serve as an initial guide for preserving and restoring the night environment of the park as visitor service facilities are rehabilitated and new buildings and infrastructure are designed and built.

Potential impacts on the night sky (ability to see stars and the effect of the sky on the landscape) have been identified for the removal or addition of buildings for each alternative. All impacts are considered long term. Where artificial lighting already exists within a complex, a substantial change in outdoor lighting is considered a minor long-term impact. Where artificial lighting would be substantially expanded beyond or reduced within an existing complex, the change is considered a moderate long-term impact. The addition of lighting to an area where no architectural lighting exists or removal of all architectural lighting from a distinct area is considered a major long-term impact.

Social and Economic Environment

Analysis of social and economic impacts has been included to evaluate potential impacts of the alternatives on the visitor population and regional economics. For the purposes of evaluating visitor population, current visitor demand and behavior were assumed to be unchanged. Visitation for 1998 was established as a baseline condition. Projected changes in park visitation were based on visitor service capacity changes associated with the Yosemite Valley Plan. Proposed actions were evaluated to estimate, when possible, their expected effects on future visitation. Future day visitation was projected to be unchanged due to the uncertain influences of numerous factors. Future visitor spending patterns and behavior were assumed to be unchanged from current conditions. The identified impacts were evaluated by comparing them to the baseline conditions.

Impacts to the Yosemite region’s economy were determined based on the effects of the expected changes in visitor spending. The region in this case consists of Madera, Mariposa, and Tuolumne Counties. Environmental consequences of implementing the alternatives were evaluated primarily based on expenditures that would be anticipated to occur within the region. The socioeconomic analysis takes into account direct and secondary project-related spending effects. Direct impacts are representative of the immediate spending within the sector of the economy where the initial stimulus occurs. Secondary effects include both induced and indirect impacts. 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 impacts of the initial stimulus on the economy from changes in business spending.

Assessments of potential social and economic impacts were based on comparisons between the No Action Alternative and the two action alternatives. The significance of these impacts was evaluated in relation to the affected environment described in Chapter III. Potential impacts were evaluated using professional judgment to ascertain reasonable conclusions with respect to the context, duration, intensity, and type of potential impacts.

Duration of Impact

Short-term impacts are those that would be temporary in duration and typically are transitional effects associated with project implementation (e.g., related to construction activities). In contrast, long-term impacts would have a permanent effect on the social and economic environments (e.g., operational activities).

Intensity of Impact

Negligible impacts are those that would not be detectible and would have no discernible effect on the social and economic environment. Minor impacts would be slightly detectible and would not be expected to have an overall effect on the character of the social and economic environment. Moderate impacts would be clearly detectible 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 would 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 are considered 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 are 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, maintains the status quo at the Curry Village and east Yosemite Valley campground project area. It provides a baseline from which to compare the action alternatives, to evaluate the magnitude of proposed changes, and to measure the environmental impacts of those changes.

 Natural Resources
Geologic Processes
Analysis
Curry Village

Existing facilities in Curry Village within the talus and rockfall zones include cabins, Curry Pavilion, and employee facilities (housekeeping, maintenance, and employee lounge area). In accordance with the Yosemite Valley Geologic Hazard Guidelines (NPS 1999b) (Appendix D), these facilities, except for Curry Pavilion, would remain within these zones since they are classified as either standard occupancy (nonessential structures such as employee housing, registration building, and retail space) or miscellaneous occupancy (campground and parking areas). Curry Pavilion is designated in the guidelines as special occupancy and can remain within the rockfall zone at the discretion of the National Park Service. Rockfall events would result in a local, long-term, moderate, adverse impact on public health and safety.

Maintenance and repair of existing utility infrastructure could occur within the talus zone or rockfall zone. Since the utilities are underground, maintenance activities would be expected to have a negligible impact on public health and safety. Conducting on-going maintenance and repair to existing utility infrastructure would result in a local, short-term, negligible, adverse impact on public health and safety.

Campgrounds

Under the No Action Alternative, the South Camp area would continue to serve as an unmarked parking area for approximately 75 cars. Talus and rockfall zones encroach upon a portion of the parking area and trail. The parking and trail facilities are considered miscellaneous structures and would remain in these zones, in accordance with the Yosemite Valley Geologic Hazard Guidelines. The potential for rockfall events would result in a local, long-term, moderate, adverse impact on public health and safety.

The majority of the existing campgrounds would continue to be located outside the talus and rockfall zones. A small portion of Upper Pines Campground is located in the talus zone (Loops E and F). Since campgrounds are considered miscellaneous structures, their location is consistent with the Yosemite Valley Geologic Hazard Guidelines. The potential for rockfall events would result in a local, long-term, moderate, adverse impact on public health and safety. Ongoing maintenance of existing utilities could occur in the talus and rockfall zones. Since the utilities are underground, these maintenance activities would be expected to have a local, short-term, negligible, adverse impact on public health and safety.

Summary of Alternative 1 Impacts. The potential for seismic events would result in a local, short-term (frequent, small seismic events), minor, adverse impact and a local, long-term (infrequent, moderate to large seismic events), moderate, adverse impact on public health and safety. The potential for rockfall events, including seismically triggered rockfall impacts, would result in a local, short- and long-term, moderate, adverse impact on public health and safety.

Cumulative Impacts

Cumulative impacts to geologic processes are based on analysis of past, present, and reasonably foreseeable future actions in the Yosemite region in combination with potential impacts of this alternative. The steep granite walls of Yosemite Valley constitute the primary geologic resource affecting the project area. Actions requiring the use of explosives for trail maintenance or road work could potentially trigger rockfall events, which would be an adverse impact, especially for existing facilities and members of the public present within the talus and rockfall zones during such an event. Risks of such impacts would be evaluated before decisions concerning the type of work to be undertaken would be made. The consistent use of park explosive guidelines and the monitoring of blasting activities would maintain the current level of risk at facilities in the Valley. Cumulative trail maintenance and road work activities would result in a local, short-term, moderate, adverse impact on public health and safety.

Rockfall hazards are being reduced through projects that relocate people and facilities away from rockfall hazard zones, such as the removal of units at Housekeeping Camp, as identified in the Yosemite Valley Plan, and the Curry Village Employee Housing Project. However, portions of existing campsites and structures in Curry Village would remain in the talus and rockfall zones. Rockfall hazards constitute a long-term, moderate, adverse impact to park visitors, as multiple facilities are located in the talus and rockfall zones. Earthquakes are unavoidable and unpredictable and represent a potentially long-term, moderate, adverse impact to public health and safety. Rockfall events on a Valleywide basis have a natural recurrence interval, and time between events increases the probability of recurrence.

Alternative 1 would contribute to this cumulative impact because facilities, including overnight accommodations, would be retained in the talus and rockfall zones. This contribution would not affect the magnitude of the cumulative impacts. Alternative 1, in conjunction with projects planned for the area, would result in a local, long-term, moderate, adverse impact to public health and safety in Yosemite Valley.

Impairment

The No Action Alternative would result in a local, long-term, negligible, adverse impact to geologic resources. The retention of facilities in the talus and rockfall zones would continue to expose structures and people to rockfall events. However, no change to existing conditions would occur that would affect geologic resources in the area. Rockfalls and seismic events would continue to occur throughout the Valley. Therefore, Alternative 1 would not impair geologic resources in the Valley.

Soils
Analysis
Curry Village and Campgrounds

The No Action Alternative would continue to generate adverse soil impacts primarily related to erosion, compaction, soil profile mixing, and soil removal at existing structures, roads, trails, campgrounds, and parking facilities throughout the project area. Soils that are coarse textured (e.g., sand) and have little organic matter provide less structural integrity and are more apt to erode than soils with a finer-grained matrix (e.g., silt or clay). Removal of vegetation in heavily traveled areas would further reduce soil stability. Continued uncontrolled access to the river would result in further erosion and decreased streambank stability. These activities would result in a local, long-term, minor, adverse impact to soil resources.

Maintenance of existing utilities could disturb soils. Since the utilities are underground, these maintenance activities would be expected to have a local, short-term, negligible, adverse impact on soil resources. The areas within existing utility corridors have been previously disturbed. Soil disturbances from utility maintenance activities could be mitigated by minimizing the area disturbed and implementing Best Management Practices.

Adverse impacts to soil resources from current uses have occurred for several decades at existing building and road sites. The continued visitor use of unpaved areas, including campsites, trails, and parking areas, would result in further degradation of soil resources. Impacts from soil loss and degradation of soil resources through foot and vehicular traffic would likely continue over an extended period of time. The continued visitor use of unpaved areas associated with Alternative 1 would result in a local, long-term, minor, adverse impact to soil resources.

Summary of Alternative 1 Impacts. Unprotected stream and river banks would continue to destabilize and erode as the Merced River and its tributaries meander throughout the Valley, resulting in a local, long-term, minor, adverse impact to soil resources. Unpaved areas, including campsites, trails, and parking areas, would experience further degradation of soil resources due to continued visitor use. Soil loss and degradation of soil resources through foot and vehicular traffic would result in a local, long-term, minor, adverse impact on existing soil resources.

Cumulative Impacts

Development projects intended to serve park visitors in Yosemite National Park have included hotels, visitor centers, campgrounds, and bridges, with associated roads and parking lots. In addition, facilities required to support park infrastructure, including employee housing, utility facilities, maintenance yards, and supply storage areas, have been developed throughout the Valley. As the popularity of Yosemite attracted a greater number of visitors, the number and magnitude of these projects increased to meet visitor demand. Past facility development has contributed to the overall degradation of soil resources in the park (i.e., soil erosion on unpaved trails and campsites from foot traffic).

Certain projects could result in increased degradation of soil resources, such as construction projects related to lodging, employee housing, and other facilities, as identified in the Yosemite Valley Plan and Yosemite Motels Expansion. However, other projects related to habitat restoration (e.g., Yosemite Valley Plan, Cook’s Meadow Ecological Restoration, and Eagle Creek Merced River Ecological Restoration) would have long-term beneficial impacts on soils. Although these types of projects may have slight site-specific, short-term, adverse effects on soils (e.g., potential short-term construction erosion and soil loss), an objective of these projects is to restore and manage natural resources and reduce soil degradation. Additionally, the impacts associated with those projects would be minimized through the use of Best Management Practices, as required by local, state, and federal regulations. For example, full implementation of the Yosemite Valley Plan would restore approximately 177 acres of soil, of which approximately 136 acres would be high-value resource soils. The cumulative projects would result in a local, long-term, minor, beneficial cumulative impact on soil resources.

Alternative 1 would result in a local, long-term, minor, adverse impact to soil resources through continued bank destabilization, erosion, and soil loss. These impacts would be offset by the beneficial impacts of the cumulative projects. Alternative 1 would not affect the magnitude of the cumulative impacts. Alternative 1, in combination with the cumulative projects, would result in a local, long-term, minor, beneficial cumulative impact on soil resources.

Impairment

The No Action Alternative would result in a local, long-term, minor, adverse impact to soil resources through continued bank destabilization, erosion, and soil loss. These impacts would be localized within the project area and would not be considered severe. The extent and quality of soil resources throughout the remainder of the Yosemite Valley would not be affected by this alternative. Therefore, Alternative 1 would not be expected to impair the soil resources of Yosemite Valley for future generations.

Hydrology, Floodplains, and Water Quality
Analysis

In this analysis, the line delineating the January 1997 flood extent is referred to as the floodplain, since the observed flood was found to be a close representation of the 100-year floodplain as modeled by the U.S. Army Corps of Engineers. Given uncertainties associated with floodplain modeling (e.g., available streamflow data, need to extrapolate data between collection points, and uncertainties in topographic data), the 1997 flood extent can be confidently used as a proxy for the 100-year floodplain.

Curry Village

Curry Village currently has no structures within the floodplain and thus does not affect water flow or the flood regime of the Merced River. Under this alternative, there would be no change in the water flow or flood regime of the Merced River. Existing parking areas and turnouts in areas such as Curry Orchard would continue to be sources of nonpoint-source pollution and would therefore continue to affect water quality. However, since no development or redevelopment would occur under this alternative, water quality conditions would remain the same, and water quality would not decline. Alternative 1 would have a local, long-term, negligible, adverse impact on water quality.

Ongoing maintenance and repairs to existing infrastructure would take place in Curry Village outside the floodplain. The areas that would be affected are within corridors that have been previously disturbed. Construction impacts could be mitigated by minimizing the area disturbed, salvaging 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.

Campgrounds

A small number of campsites on the southeast end of Upper Pines Campground are within the floodplain. However, there are no structures within the floodplain and thus no impact to water flow or the flood regime of the river. Lower Pines campsites at the northwestern area also are within the floodplain. These areas, including drive-in campsites and restrooms, are currently at risk of flooding damage and also have the potential to affect the river’s water flow and restrict its flood capacity. The recreational vehicle dump station currently within the River Protection Overlay would not be demolished and would continue to affect water quality in and downstream of the project area. The unmitigated flood hazard to structures in the floodplain under Alternative 1 would result in a local, long-term, moderate, adverse impact. The continued operation of campground facilities and the recreational vehicle dump station in the floodplain would result in a local, long-term, minor, adverse impact on water quality.

Maintenance of existing utility facilities could take place within the floodplain. The use of heavy equipment presents the potential for accidental releases of fuels or other hazardous substances that could affect local surface water or groundwater quality. Impact from maintenance activities could be mitigated by minimizing the area disturbed, salvaging existing soils for use as fill, and implementing Best Management Practices to reduce the potential for water quality impacts associated with soil erosion and construction equipment releases.

Summary of Alternative 1 Impacts. The No Action Alternative would result in a local, long-term, moderate, adverse impact to water quality due to the continued operation of campground facilities and the recreational vehicle dump station in the floodplain, close to the river. The ongoing maintenance of existing utility facilities would be expected to result in a short-term, minor to moderate, adverse effect on surface water hydrology and water quality in the project area. The unmitigated flood hazard could result in damage to facilities, such as that sustained during the 1997 flood, and would be considered a local, long-term, moderate, adverse impact.

Cumulative Impacts

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

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, repair of flood damaged trails at Happy Isles, Eagle Creek Merced River Ecological Restoration, and implementation of the East Yosemite Valley Utilities Improvement Plan (NPS 2003a). Other proposed future projects include the Lower Yosemite Fall Project, Cascades Diversion Dam Removal, and Happy Isles Dam Removal. Cumulatively, these projects are anticipated to have beneficial impacts on hydrologic processes and water quality of the Merced River. Alternatively, adverse impacts could occur by implementing the Yosemite Valley Plan projects, including construction of additional lodging and a visitor transit center in Yosemite Valley. Overall, implementing projects identified in the Yosemite Valley Plan would have a long-term, minor, beneficial effect on river hydrologic processes, floodplains, and water quality.

The Merced River Plan (NPS 2001a) 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 and Resource Protection framework (see Chapter V, Merced Wild and Scenic 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 the existing facilities in the floodplain, including the utility infrastructure, which would affect the magnitude of the cumulative impacts. The past, present, and future projects in Yosemite Valley, considered cumulatively with Alternative 1, would have a local, long-term, negligible, beneficial impact on hydrologic processes, flood hazards, and water quality.

Impairment

Alternative 1 would result in a local, long-term, minor to moderate, adverse impact to hydrology, flooding, and water quality due to the continued operation of campgrounds and the recreational vehicle dump station within the floodplain and repairs to existing utility systems. Because these impacts are expected to be minor to moderate and localized, Alternative 1 would not impair the hydrologic resources of Yosemite Valley for future generations.

Wetlands
Analysis

Wetlands within Curry Village and the campgrounds experience ongoing, adverse impacts from encroachment by non-native vegetation and conifers, fragmentation from roads and infrastructure, and trampling (NPS 2000a). Roads and multi-use trails negatively affect wetlands by diverting surface and subsurface flows as well as generating and concentrating polluted runoff (NPS 2000a). Wetlands not immediately adjacent or downslope of buildings, paved surfaces, or high use areas are somewhat buffered from these impacts and therefore provide important habitat values.

Curry Village

The wetlands at Curry Village consist of palustrine forest, palustrine emergent, palustrine scrub shrub, and riverine intermittent streambed. Visitation at Curry Village has resulted in a large number of informal paths between the cabins. The development of paths and trampling have reduced the cover of vegetation and compacted the soil, exacerbating surface water runoff into wetlands. Curry Village has a relatively large number of developed and paved surfaces, which surround or bisect most of the wetlands in this area. The existence of these surfaces likely degrades wetlands in Curry Village due to water diversion and polluted runoff. Under Alternative 1, wetlands in Curry Village would continue to experience local, long-term, adverse impacts from pedestrian traffic and runoff. Given that wetlands are a high-value resource and that most of the wetlands in Curry Village are likely affected by these activities, the impacts are considered to be major in intensity.

Campgrounds

The wetlands in the South Camp area consist of palustrine emergent and riverine intermittent streambed. Some of these wetlands are affected by the adjacent paved trail, but most are located away from human disturbance. These wetlands drain to Upper Pines then Lower Pines campgrounds before reaching the Merced River. A portion of these wetlands experience a local, long-term, minor, adverse impact due to the presence of people on trails that cross the riverine intermittent streambed wetlands. Due to the small area of disturbance, these impacts are of minor intensity.

The wetlands at Upper Pines Campground consist of palustrine forest, palustrine emergent, palustrine scrub shrub, and riverine intermittent streambed. Some of these wetlands drain to the Merced River through Lower Pines Campground, while others drain directly to the Merced River. Some of the riverine intermittent streambed wetlands drain the restored fen near Happy Isles. Under Alternative 1, the wetlands at Upper Pines would continue to experience a local, long-term, moderate, adverse impact due to the presence of people in the campground.

The wetlands at Lower Pines Campground include palustrine scrub shrub and riverine intermittent streambed. These wetlands flow to the Merced River. Under Alternative 1, wetlands at Lower Pines would continue to experience a local, long-term, minor, adverse impact and a reduction in wildlife value due to trampling by campground visitors.

Summary of Alternative 1 Impacts. The No Action Alternative would result in an overall local, long-term, moderate, adverse impact to existing wetlands due to pedestrian foot traffic that results in trampling of vegetation, erosion of streambanks, and increases in sedimentation into waterways.

Cumulative Impacts

Cumulative impacts 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. Beneficial cumulative effects on wetlands include wetland restoration, rehabilitation projects, and ecosystem management. Adverse cumulative 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 and Resource Protection framework. Implementation of the Yosemite Valley Plan would result in a net gain of wetlands in Yosemite Valley through actions such as restoration of the upper Merced River to natural conditions; removal of roads through Ahwahnee Meadow; and removal of other bridges (e.g., Sugar Pine and possibly Stoneman) affecting the natural flow of the Merced River. Farther downstream, removal of the Cascades Diversion Dam would also 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 and construction of a vehicle bridge across Yosemite Creek near Yosemite Lodge, 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 local, long-term, major, beneficial cumulative effect on wetlands within Yosemite Valley due to wetland restoration efforts.

Alternative 1 would have a local, long-term, moderate, adverse impact to existing wetlands at Curry Village, and a local, long-term, minor, adverse impact to wetlands in Lower Pines Campground, due to continued trampling by park visitors. The beneficial impacts associated with the cumulative projects would overshadow these effects, and Alternative 1 would not affect the magnitude of the cumulative impacts. Alternative 1, in combination with the cumulative projects, would result in a net long-term, major, beneficial effect on wetland patterns.

Impairment

The No Action Alternative would result in a local, long-term, negligible, adverse impact to existing wetlands at South Camp and Upper Pines Campground; a local, long-term, minor, adverse impact to existing wetlands at Lower Pines Campground; and a local, long-term, moderate, adverse impact to existing wetlands at Curry Village. Although the Merced River system and its related wetlands are key resources within Yosemite Valley, the effect of this alternative on wetland resources would be primarily localized and would not diminish the overall value of this resource. The extent and quality of wetland and associated riparian habitats throughout Yosemite Valley would remain largely unaffected, and wetland resources would not be impaired for future generations.

Vegetation
Analysis

Existing impacts to the vegetation in the project planning area were identified in the Final Yosemite Valley Plan/SEIS. These include removal and alteration of ecological processes such as fire, with a resulting alteration of the species composition and structure of the vegetation, trampling of understory vegetation, and fragmentation of vegetation by existing roads and development.

Curry Village

Trampling of understory vegetation would continue to occur at Curry Village. Trampling and alteration of natural plant succession and stand density would also continue under this alternative, resulting in a local, long-term, moderate, adverse impact. Given that the extent of this disturbance extends throughout Curry Village, this impact is considered moderate.

Campgrounds

Vegetation of Upper Pines and Lower Pines Campgrounds would continue to be affected by camping activity under Alternative 1. Campers currently trample the understory vegetation and remove downed wood for campfires from the campground areas. As a result, understory vegetation is largely absent from the campgrounds. Vegetation outside of the campground areas has a dense understory that is not affected by trampling or wood removal. The absence of fire may affect this area by increasing the density of trees and altering the species composition of the overstory. The continued camping activity in Upper Pines and Lower Pines Campgrounds would result in a local, long-term, moderate, adverse impact to vegetation.

Summary of Alternative 1 Impacts. Under Alternative 1, existing impacts to vegetation in Curry Village and the Upper and Lower Pines Campgrounds would continue. Continued camping activity, including vegetation trampling and disruption of normal ecological processes such as fire, would result in a local, long-term, adverse impact to vegetation. The majority of habitat disturbance occurs in natural communities that are widespread in Yosemite Valley and the region; therefore, overall impacts would be moderate in intensity.

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 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 would be mixed, combining both adverse and beneficial effects. Beneficial cumulative effects on vegetation include restoration, rehabilitation projects, and ecosystem management. Adverse cumulative 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 and Resource Protection framework. Full implementation of the Yosemite Valley Plan would restore over 100 acres, of which a substantial amount would be high-value resource vegetation in Yosemite Valley. Such proposed actions include removal of roads through Ahwahnee Meadow and natural vegetation restoration actions in several areas. Although certain Yosemite Valley Plan projects have the potential to adversely affect local vegetation (such as the Curry Village Employee Housing, Lower Yosemite Fall, and Yosemite Lodge Area Redevelopment projects) the cumulative projects would increase the overall size, connectivity, and integrity of vegetation within the watershed, resulting in a long-term, major, beneficial cumulative effect on vegetation.

Alternative 1 would have a local, long-term, moderate, adverse effect on vegetation due to the continued trampling of vegetation in the project area. However, the beneficial effects of the cumulative projects would overshadow this impact, and Alternative 1 would not alter the magnitude of the cumulative impact. Alternative 1, in combination with the cumulative projects, would result in a net long-term, major, beneficial effect on vegetation patterns.

Impairment

Alternative 1 would result in a local, long-term, moderate, adverse impact to vegetation in the immediate vicinity of the project sites. The effect of this alternative on vegetation would be localized and would not be considered severe. The extent and quality of vegetation throughout the remainder of Yosemite Valley would remain unaffected by this alternative. Therefore, Alternative 1 would not impair vegetation resources in Yosemite Valley for future generations.

Wildlife
Analysis

Ongoing impacts to wildlife in the project area were identified in the Final Yosemite Valley Plan/SEIS. Impacts include some loss of forest understory due to human access and fire suppression, removal of dead tree or snag habitat, availability of human food and trash, and noise and visual disturbance associated with human activities and vehicles. Wildlife mortality and habitat fragmentation also occurs due to vehicle travel. These impacts reduce the amount and quality of areas available to sensitive species that require undisturbed habitat for essential activities such as nesting, roosting/resting, and foraging. Other species tolerant of human disturbance may benefit from these impacts, which provide foraging opportunities and human structures as nesting or resting areas.

Curry Village

Wildlife in Curry Village would continue to experience impacts due to trampling of vegetation and soils and the near-constant presence of people. The majority of species that occur in Curry Village are likely habituated to human disturbance, and some species may be attracted to the area to forage on food waste and trash or to nest or roost in buildings or other developed structures. Sensitive species associated with undisturbed habitats are likely absent in most areas of Curry Village, given the high degree of habitat disturbance and human activity. The continued reduction of available habitat to sensitive wildlife would result in a local, long-term, moderate, adverse impact to wildlife.

Campgrounds

Sensitive wildlife in the South Camp area would continue to experience a reduction of available habitat because of human and habitat disturbance along surrounding paths. Several relatively large areas of undeveloped habitat exist in the eastern portion of the Upper Pines Campground and throughout the South Camp area that also support high-value wetland habitat. Given the relatively low intensity of the campground development as compared to that at Curry Village and the presence of high-value habitat blocks, the impact to wildlife under Alternative 1 would continue to be local, long term, minor, and adverse.

Summary of Alternative 1 Impacts. Wildlife would continue to be affected by the constant presence of people and trampling of vegetation in the project area. These impacts reduce the amount and quality of areas available to sensitive species that require undisturbed habitat for essential activities such as nesting, roosting/resting, and foraging, resulting in an overall local, long-term, moderate, adverse impact to wildlife.

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, 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. Implementation of the Yosemite Valley Plan would restore 141 acres of river-associated wildlife habitat in Yosemite Valley. 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 and Resource Protection framework. Implementation of the Visitor Experience and Resource Protection framework (included in both the Merced River Plan and Yosemite Valley Plan) would help reduce adverse effects of visitor use on wildlife habitat and patterns.

Cumulative actions would have a local, long-term, moderate to major, beneficial effect on wildlife within Yosemite Valley because of the habitat restoration provisions of the Yosemite Valley Plan and Merced River Plan. Thus, past, present, and reasonably foreseeable future actions would have a net local, long-term, moderate to major, beneficial effect on wildlife patterns. Alternative 1 would have a local, long-term, moderate, adverse effect on wildlife, due to the loss of forest understory caused by human access, fire suppression, removal of dead tree or snag habitat, availability of human food and trash, and noise and visual disturbance associated with human activities and vehicles. However, because the cumulative projects would overshadow the localized effects, Alternative 1 would not affect the magnitude of the cumulative impacts. Alternative 1 and the cumulative projects would result in a net long-term, major, beneficial effect on wildlife patterns.

Impairment

Alternative 1 would result in a local, long-term, moderate, adverse impact to wildlife. The extent and quality of wildlife habitat throughout the remainder of Yosemite Valley would remain unaffected by this alternative. Therefore, Alternative 1 would not impair wildlife within Yosemite Valley for future generations.

Special-Status Species
Analysis

A variety of special-status species have the potential to occur in the project area (table III-6). These species include the Yosemite Mariposa sideband snail and Mt. Lyell salamander (both of which require moisture as part of their habitat), and species that require standing water such as California red-legged frog, foothill yellow-legged frog, and western pond turtle. Cooper’s hawk and spotted owl generally nest in areas of dense tree cover that are away or buffered from human disturbance. Spotted owl is considered the only federally listed species with the potential to occur within the project area. The peregrine falcon requires cliffs or tall structures for nesting. The special-status bats roost and nest in large trees, cracks in cliffs, or structures and forage over open water, meadows, or forested areas.

Impacts to special-status species would be the same as those described for sensitive wildlife. These impacts ultimately serve to exclude or restrict use of many of the project areas by special-status species.

Curry Village

Due to human and habitat disturbances, Curry Village does not likely provide more than occasional habitat for special-status species, such as raptors or bats that may at times forage from or roost in trees and buildings. Mariposa sideband snail is the only special-status species known to have occurred historically in Curry Village. Special-status species that have the potential to incur the greatest ongoing impacts due to human and habitat disturbances are shown on figure III-4. These species are known to occur or have been observed recently in or adjacent to the project planning areas. Impacts to these species may include restricted use of habitats or direct disturbance to individuals and are considered local, long term, moderate, and adverse. Other species such as the California red-legged frog and foothill yellow-legged frog, which are likely extirpated from Yosemite Valley, are not likely to be affected by these impacts.

Campgrounds

The only special-status species known to be present within the campgrounds (Whitney’s sedge) occurs in the South Camp area (figure III-4). This species likely sustains the greatest adverse impact due to unofficial trail use in the South Camp area by visitors who may trample plants. The absence of wood on the forest floor in campground areas reduces the availability of fungus, which indirectly affects spotted owl foraging opportunities. Fungus is a major dietary component for flying squirrels, which in turn are a significant component of the diet of California spotted owls. Thus, removal of wood from areas within and adjacent to campgrounds significantly reduces foraging opportunities for California spotted owl.

Alternative 1 would continue to result in a local, long-term, minor, adverse impact to special-status species due to habitat degradation from human use and habitat fragmentation. The South Camp area is located at the edge of Yosemite Valley, next to the talus zone, which likely reduces visitor access to this area as compared to other areas. The minor amount of trail and parking lot development would result in a local, long-term, minor, adverse effect on special-status species in South Camp. Alternative 1 would continue to result in a local, long-term, minor, adverse impact due to the degradation and fragmentation of the habitat at Upper Pines Campground and the degradation of habitat due to vegetation trampling by campers. For the abandoned portion of the Lower Pines Campground, there could be a local, long-term, minor, beneficial impact from the implementation of the Merced River Plan, which protects natural resources adjacent to the river, including bat foraging areas, raptor hunting and perching areas, amphibian and turtle habitat, and forest habitat for other species.

Summary of Alternative 1 Impacts. The No Action Alternative would continue to contribute to habitat degradation from human use and habitat fragmentation. These impacts likely exclude or restrict use of the project area by certain species, such as Mariposa sideband snail, spotted owl, Cooper’s hawk, peregrine falcon, special-status bats, western pond turtle, Mt. Lyell salamander, and special-status plants known to occur in the project vicinity. Therefore, Alternative 1 would result in an overall local, long-term, moderate, adverse impact to special-status species.

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 have been manipulated almost since the inception of the park. Regional wildlife and vegetation patterns have been historically affected by logging, fire suppression, rangeland clearing, grazing, mining, draining, damming, diversions, and the introduction of non-native species. 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 and Resource Protection framework. Full implementation of the Yosemite Valley Plan would increase the size, continuity, and integrity of habitats, especially meadow, riparian, black oak, and upland habitats, for special-status species in Yosemite Valley. Although certain Yosemite Valley Plan projects, such as the Curry Village Employee Housing, Lower Yosemite Fall, and Yosemite Lodge Area Redevelopment projects, have the potential to adversely affect local special-status species, full implementation of the cumulative projects would have a long-term, moderate, beneficial effect on habitat for special-status species by enhancing habitat connectivity, size, and structure within Yosemite Valley.

Although Alternative 1 would continue to contribute to habitat degradation due to human use and fragmentation, this impact would be overshadowed by the improvements to habitat connectivity, size, and structure that would occur under the cumulative projects. Alternative 1 would not affect the magnitude of the cumulative impacts. Thus, past, present, and reasonably foreseeable future actions, in combination with Alternative 1, would have a net local, long-term, moderate, beneficial effect on special-status species.

Impairment

The No Action Alternative would continue to result in a local, long-term, minor, adverse impact to special-status species due to habitat degradation from human use and habitat fragmentation. For the abandoned portion of the Lower Pines Campground, there may be a local, long-term, minor, beneficial impact from the implementation of the Merced River Plan. The extent and quality of habitat for the special-status species throughout the rest of Yosemite Valley would remain unaffected. Therefore, Alternative 1 would not impair special-status species or their habitats in Yosemite Valley 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 in terms of the planning areas used in other resource sections. This section presents a qualitative assessment of air emissions related to continued operation of existing facilities and utility systems in the project area, including emissions related to ongoing maintenance of the utility facilities.

Alternative 1 would not result in changes to existing air pollution sources in the project area. Existing emissions from sources within the project area – including furnaces, boilers, woodstoves, campfires, generators, barbecues, prescribed fires, motor vehicles, and operations and maintenance activities – would continue at approximately their existing levels. Alternative 1 would include use of construction equipment to repair the maintain the existing utility infrastructure. Continued maintenance of lodging, camping, and parking in their existing conditions would encourage visitors to drive through the area, maintaining the existing levels of vehicular emissions and traffic-related fugitive dust throughout the project area.

Air quality effects from this alternative would relate primarily to construction equipment emissions, dust generated during planned repair activities, and the continued vehicular emissions from vehicles accessing Curry Village and the campgrounds. Emissions from construction equipment would occur in the vicinity of utility maintenance activities and could result in mildly unpleasant odors that could be noticeable to park visitors in nearby areas. Construction activities 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.

Continued vehicle traffic associated with visitor use, lodging, and parking would result in continued vehicle-related emissions, particularly ozone precursor, carbon monoxide, and associated fugitive dust, resulting in a local and regional, long-term, minor, adverse impact to air quality. The replacement of private vehicles and transit vehicles with lower emission vehicles over time, however, would result in a decrease of emissions over current levels. The use of Best Management Practices during construction activities and the replacement of private vehicles over time would result in an overall regional, long-term, minor, beneficial impact to air quality. A detailed quantitative summary of the regional air quality impacts associated with the No Action Alternative is included in Chapter 4 of the Yosemite Valley Plan.

Summary of Alternative 1 Impacts. Alternative 1 would result in a local, short-term, minor, adverse effect to air quality from construction activities, which could be mitigated by the use of Best Management Practices, as described above. Alternative 1 would result in a local and regional, long-term, minor, adverse impact to air quality associated with continued levels of vehicle traffic and visitor use. Alternative 1 would result in a local and regional, long-term, negligible, adverse impact as private and fleet vehicles are replaced over time with lower-emission vehicles. Overall, this alternative would have a local, long-term, negligible, adverse impact to air quality.

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 near or within the project area.

Since 1950, the population of California has tripled, and the rate of increase in vehicle-miles-traveled has increased sixfold. 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 are over 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 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, some of which would be implemented under Alternatives 2 and 3. Parking lots 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 with respect to nitrogen oxide emissions due to the use of diesel buses through 2015, but a long-term, minor to major, beneficial impact with respect 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 a local, short-term, minor, adverse air quality effect, the general goal of the project is to relieve congestion and to 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 regional, long-term, minor, beneficial effect on air quality. In addition, over the next 15 to 20 years, substantial reductions in emissions would result from the gradual replacement of older vehicles, including fleet vehicles, with newer, lower-emission vehicles, resulting in a local, long-term, minor, beneficial impact on air quality.

Other reasonably foreseeable future National Park Service projects not anticipated to have a net long-term adverse or beneficial effect on air quality include Replacement/Rehabilitation of Yosemite Valley Main Sewer Line, Eagle Creek Merced River Ecological Restoration, Happy Isles to Vernal Fall Trail Reconstruction, Repair Flood-Damaged Trail Bridges at Happy Isles, and Happy Isles Site Improvements.

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 impact on air quality in Yosemite Valley.

Under Alternative 1, the local and regional, long-term, minor, adverse impact to air quality associated with continued levels of vehicle traffic and visitor use in the project area would not affect the magnitude of the cumulative impact. The regional programs and other Valleywide programs to reduce vehicle emissions would overshadow the localized adverse impact of Alternative 1. Alternative 1, in combination with other reasonably foreseeable projects, would result in a local, long-term, moderate, beneficial impact on air quality in Yosemite Valley.

Impairment

Implementation of Alternative 1 would be expected to result in a local, long-term, minor, adverse impact from construction activities and continued vehicular emissions from visitors accessing Curry Village and the campgrounds. Construction impacts could be mitigated by use of Best Management Practices, and vehicular emissions would be reduced over time through the introduction of lower-emission vehicles. These impacts would not impair park resources for future generations.

Noise
Analysis

Alternative 1 would not result in long-term changes to existing noise levels in the project area. All vehicle access routes, traffic levels, housing and lodging locations and densities, and camper and visitor activities and intensities would remain at existing levels. These activities would result in a local, short-term, negligible to moderate, adverse impact to the noise environment. Vehicle noise would typically not be noticeable at a distance of 100 feet or more from Yosemite Valley roads, except for individual sound events such as the passage of buses. Ambient noise levels found in lodging and recreation areas would remain generally low, with peak nonvehicle noises still occurring from National Park Service and concession operations. Both vehicle and nonvehicle noise would continue to affect the experiences of both visitors and residents. A detailed analysis of existing and projected noise levels in the project area under the No Action Alternative can be found in the Final Yosemite Valley Plan/SEIS.

Ongoing utility repair activities would involve the operation of heavy equipment at repair sites, which could generate substantial amounts of noise during these operations. Since utility infrastructure is located throughout the project area, park visitors and employees could be affected during construction. Table IV‑3 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.

 

Table IV‑3 Typical Noise Levels from Construction Equipment
Equipment	Typical Noise Level (dBA) 50 feet from the Source
Air Compressor	81
Backhoe	80
Compactor	82
Concrete Mixer	85
Concrete Pump	82
Crane, Derrick	88
Crane, Mobile	83
Dozer	85
Generator	81
Grader	85
Impact Wrench	85
Jack Hammer	88
Loader	85
Paver	89
Pneumatic Tool	85
Pump	76
Rock Drill	98
Roller	74
Saw	76
Scraper	89
Truck	88
dBA = A-weighted decibels Source: FTA 1995

 Winter ambient noise levels at various locations in Yosemite Valley ranged from 59 to 69 day-night level (DNL) in 1999 (NPS 2000a). Summer ambient noise levels would 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 decibels, typically in short bursts over the duration of the project. These noises would be perceived as 16 or more times louder than a typical vehicle.

Curry Village

Ongoing utility maintenance activities in Curry Village would cause temporary noise impacts on park residents and visitors in the Curry Village area, resulting in a local, short-term, moderate to major, adverse impact.

Campgrounds

Campground utility maintenance activities would most likely be scheduled to occur during the fall or winter, when visitor numbers are low. Although Lower Pines Campground is closed during the winter, Upper Pines Campground remains open, and visitors camping or hiking in this area could be affected by construction noise as during utility maintenance activities. In addition, construction noise could result in a short-term, moderate, adverse impact to other park visitors farther removed from the maintenance activities. Utility maintenance activities would be short term in duration.

Summary of Alternative 1 Impacts. Noise generated by routine maintenance and debris removal activities under Alternative 1 would result in a local, short-term, moderate to major, adverse impact to park visitors, residents, and contractors in the vicinity of repair projects. Alternative 1 would not be expected to have a long-term impact on ambient noise levels in Yosemite Valley.

Cumulative Impacts

Cumulative effects on 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 levels near and within the project area.

The Yosemite Valley Plan proposes to enhance the quality of the visitor experience in Yosemite Valley by reducing automobile congestion and traffic, limiting crowding, and expanding orientation and interpretive 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 Yosemite Valley could be used to intercept day visitors and shift those visitors to Valley-bound shuttle buses. Overall, sound levels associated with traffic along most roadways in Yosemite Valley would be reduced, resulting in a local, long-term, minor, beneficial impact.

The Merced River Plan proposes further actions to both enhance visitor experience as well as 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. Protecting natural resources and maintaining visitor-intensive uses in the appropriate management zones under this plan would have additional local, long-term, minor, beneficial impacts on the noise environment.

Reasonably foreseeable future actions proposed in the Yosemite Valley Plan could have beneficial or adverse impacts on the Valley noise environment. 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 and thereby reducing private automobile trips. Although the Shuttle Bus Replacement Project would have a local, short-term, minor, adverse noise effect, the general goal of the project is to relieve congestion and to 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 local, long-term, minor, 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 upon ridership levels, the corresponding number of automobile trips that would be avoided, and the technology selected for the buses. The noise associated with the installation of multiple projects in Yosemite Valley would represent a short-term, moderate adverse impact that could last for several years as the projects are implemented.

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 impact on the ambient noise environment, except for short-term, localized impacts during construction.

The maintenance of the existing utility system and other facilities would contribute to cumulative noise in the project area, but this contribution would not alter the magnitude of the cumulative impacts. Alternative 1, in combination with the cumulative projects, would result in a local, long-term, negligible, beneficial impact to the noise environment.

Impairment

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

Cultural Resources
Archeological Resources
Analysis

Alternative 1 would not change the management and treatment of archeological sites in the project area. Adverse impacts would continue to result from visitor use and periodic maintenance of existing facilities. Sensitive resources could also be exposed or damaged through natural processes, such as erosion along the banks of the Merced River. Any site-specific planning and compliance actions would be performed in accordance with stipulations in the park’s 1999 Programmatic Agreement.

Maintenance of the utility system throughout the project area has the potential to further affect several recorded archeological sites and could also affect unrecorded buried cultural resources. 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 typically untraveled locations. A similar impact would be possible with vehicle traffic, if detours increased visitation at less-visited locations, bringing an increased number of people into contact with isolated or hard-to-find cultural resources. This would be a short- and potentially long-term impact, but probably a minor one when compared to all potential visitor contacts with the park’s 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.

Curry Village

Maintenance of the utility system in Curry Village has the potential to affect cultural resources. If cultural resources could not be avoided, the site would be evaluated to determine its potential eligibility for inclusion on the National Register of Historic Places. If the site was determined to be eligible for the National Register, careful project design and data recovery to retrieve important information, carried out in accordance with the 1999 Programmatic Agreement, would result in a local, long-term, minor adverse impact.

Campgrounds

Maintenance of the utility system throughout the campgrounds has the potential to affect cultural resources. If cultural resources could not be avoided, the site would be evaluated to determine its potential eligibility for inclusion on the National Register of Historic Places. If the site was determined to be eligible for the National Register, careful project design and data recovery to retrieve important information, carried out in accordance with the 1999 Programmatic Agreement, would reduce the intensity of the local, long-term, adverse impact from moderate to minor.

Summary of Alternative 1 Impacts. Alternative 1 would not change the treatment or management of archeological resources in the project area. Because Alternative 1 consists exclusively of maintenance to the existing utility infrastructure, the number of archeological resources that could sustain adverse impacts is limited. Any site-specific planning and compliance actions would be performed in accordance with stipulations in the park’s 1999 Programmatic Agreement, which mandate data recovery excavation to retrieve important information, thus reducing the intensity of the local, long-term, adverse impact to minor under the National Environmental Policy Act.

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. In general, archeological resources within Yosemite Valley are the result of thousands of years of human occupation. Previous development, operation, and maintenance of facilities within Yosemite Valley have disturbed, destroyed, or compromised numerous archeological resources. Two archeological sites are situated within the Upper Pines Campground, and a third is within easy walking distance between the campground and the river. Two of these sites are highly valued resources; one is the large historic village of Ummataw with an associated archeological component, and another is the old American Indian site of Hookehatchke, also with associated archeological remains. Another site with historic and prehistoric components is situated in the Lower Pines Campground and has been adversely affected by visitor usage, and campground and amphitheater construction. Five surface and subsurface archeological deposits within and in the vicinity of Camp Curry have sustained a local, long-term, negligible to minor, adverse impact as a result of past maintenance activities. These past actions have had a local, permanent, minor to moderate, adverse cumulative impact on archeological resources.

It is anticipated that these sites, and other, as-yet-undiscovered subsurface deposits, may continue to be affected by ongoing operational and maintenance activities, as well as direct and indirect impacts from future development, vandalism, visitor access, and natural processes. The Visitor Experience and Resource Protection study and program, established under the Yosemite Valley Plan, will monitor existing and desired conditions (including cultural resources), thereby minimizing the degree of adverse impacts. The National Park Service would follow guidelines of the 1999 Programmatic Agreement, avoiding adverse impacts to archeological resources to the greatest extent possible through the use of barriers or fencing, monitoring of excavations in sensitive areas, and project redesign. Where not possible, data involving prehistoric and historic lifeways would be recovered through recordation and data recovery according to provisions in the Programmatic Agreement. It is anticipated that these actions would result in a local, permanent, negligible to minor, adverse cumulative impact to archeological resources.

Alternative 1 would continue the existing management and treatment of archeological resources, with limited potential for causing impacts to archeological resources. Alternative 1 would not change the magnitude of the cumulative impacts and, in combination with the cumulative projects, would result in a local, permanent, negligible to minor, adverse cumulative impact to archeological resources.

Impairment

Although several sites, including high-value cultural resources, are located within the area of potential effect, the impact of this alternative on archeological resources would be minimized through avoidance where possible and monitoring of ground-disturbing activities. For those impacts that could not be avoided, recordation and/or data recovery would be conducted, as outlined in the 1999 Programmatic Agreement. Any adverse impacts would be primarily localized and would not be considered severe. In addition, Alternative 1 would not change the treatment or management of archeological resources. With implementation of the mitigation measures outlined above, Alternative 1 would result in a local, permanent, negligible to minor, adverse impact and would not impair archeological resources for future generations.

 Ethnographic Resources
Analysis

Alternative 1 would not change the management or treatment of ethnographic resources in the Curry Village and east Yosemite Valley campgrounds area. The three identified ethnographic village sites and portions of the three ethnographic gathering areas located within the area of potential effect have been adversely affected by campground development and maintenance and visitor use. It is anticipated that these areas would continue to sustain adverse impacts from existing campground and visitor facilities. Archeological components associated with two of the three ethnographic village locations are discussed above. Any site-specific planning and compliance actions would be performed in accordance with stipulations in the park’s 1999 Programmatic Agreement, and park staff would continue to consult with culturally associated American Indian tribes under this Programmatic Agreement and the cooperative agreement for traditional uses.

Maintenance of the utility infrastructure throughout the project area has the potential to further affect several recorded ethnographic sites. The severity of potential impacts to traditional cultural properties could only be determined in consultation with the people who place a cultural value on the resource. Implementation of the construction mitigation measures identified in Chapter II would limit disturbances within these resource areas, but determining how to mitigate potential direct and indirect impacts to the cultural value of a property must come through consultation with the affected individuals.

Curry Village and Campgrounds

Maintenance of the utility infrastructure could affect ethnographic resources. Construction activities would be monitored within ethnographic resource areas as a standard procedure for any ground-disturbing activities, resulting in a local, short--term, negligible to minor, adverse impact. Consultation regarding use of traditional resource gathering areas could result in the short-term designation of alternative gathering areas, or construction activities could be timed to avoid affecting these areas during periods when use of the sites by tribal people would occur.

Summary of Alternative 1 Impacts. Ethnographic resources would continue to be treated and managed as they are at present. Maintenance activities could adversely affect ethnographic resources. Because construction activities would be short term and localized, it is expected that consultation would produce treatment solutions to mitigate any impacts considered adverse under the National Historic Preservation Act, resulting in a local, short--term, negligible to minor, adverse impact under the National Environmental Policy Act.

Cumulative Impacts

Cumulative impacts to ethnographic resources are based on analysis of past, present, and reasonably foreseeable future actions in Yosemite Valley in combination with potential impacts of this alternative. Ethnographic resources and their traditional cultural associations have been lost or damaged in Yosemite Valley through past development, visitor use, natural events, and widespread disruption of cultural traditions. Nevertheless, Yosemite National Park retains many sites and resources of significance to local and culturally associated American Indians.

In general, the ethnographic resources within the vicinity of Curry Village and Lower and Upper Pines Campgrounds are the result of thousands of years of human occupation. Development, operation, and maintenance of facilities within Yosemite Valley have disturbed, destroyed, or affected the integrity of numerous ethnographic resources, which has had a local, permanent, minor, adverse cumulative impact.

Reasonably foreseeable future actions proposed in the region that could have an adverse cumulative impact on ethnographic resources in Yosemite Valley include development-related maintenance projects. Traditional gathering areas would be further disturbed by visitor use and natural events that would continue to have a local, permanent, minor, adverse impact on ethnographic resources.

Foreseeable projects such as Eagle Creek Ecological Restoration, Cook’s Meadow Ecological Restoration, and Lower Yosemite Fall projects could beneficially affect ethnographic resources in Yosemite Valley. These cumulative projects could restore native plant habitat, which would have a local, permanent, minor, beneficial impact on ethnographic resources. The intensity of this impact would depend on the extent to which gathering sites were restored and access to traditional use areas continued.

The National Park Service would continue to consult with culturally associated American Indian tribes according to stipulations of the Programmatic Agreement and specific agreements – such as the October 17, 1999 Agreement Between the National Park Service, Yosemite National Park, and the American Indian Council of Mariposa County, Inc. for Conducting Traditional Activities – to develop appropriate mitigation strategies for impacts to ethnographic resources. Such strategies could include identifying and assisting in providing access to alternative resource gathering areas, continuing to provide access to traditional use or spiritual areas, and screening new development from traditional use areas. Therefore, the cumulative projects in Yosemite Valley would result in a local, permanent, minor, adverse impact on ethnographic resources due to the disturbance of the remaining resources.

The short-term, localized construction impacts identified for Alternative 1 associated with maintenance of existing utility infrastructure would not change the magnitude of the cumulative impact. Alternative 1, in combination with the cumulative projects, would result in a local, permanent, minor, adverse impact on ethnographic resources.

Impairment

Alternative 1 would have a minor adverse impact on ethnographic resources, but not with respect to their treatment and management. Therefore, Alternative 1 would not impair ethnographic resources for future generations.

Cultural Landscape, Historic Sites, and Structures
Analysis
Natural Systems and Features

Under Alternative 1, the general pattern of development in the project area and the historic relationship between the natural and built environment would not change. Alternative 1 would not remove structures or features from the project area. Implementation of the River Protection Overlay would provide some protection of the Merced River corridor. Ongoing park management of the meadow, woodland, and forest areas would result in a local, long-term, minor beneficial impact to the natural systems and features that contribute to the Valleywide cultural landscape.

Historic Land-Use Patterns

Historic land-use patterns would not change. The historic developed area of Curry Village would remain and would continue to function as it does today, resulting in a local, long-term, negligible, beneficial impact.

Historic Circulation Systems

There would be no changes to the current, historic circulation systems in the project area. Southside Drive would remain at its present location, crossing Stoneman Meadow; vehicular access to the east end of the Valley and to the project area would continue to be restricted, resulting in a local, long-term, negligible, beneficial impact.

Curry Village and the Camp Curry Historic District

The historic design and spatial organization of the Curry Village developed area would remain as it exists today. Historic structures and landscape resources would remain intact and would be managed under current treatment policies. These policies would preserve and protect, to the greatest extent possible, the integrity and character of the historic district, while minimizing deterioration caused by normal use and natural forces.

However, without implementation of some of the projects mandated by the Yosemite Valley Plan, the facilities in the Valley would be inadequate to satisfy the needs of the park’s visitors, and thus the wear and tear would continue on the historic fabric of some of the most significant buildings. Under Alternative 1, no rehabilitation of Curry Village’s historic buildings or structures would be undertaken. Ongoing processes of deterioration due to weather, pests, and human actions would continue unchecked. This overuse and deterioration of the individual buildings would ultimately lead to a general degradation of the Camp Curry Historic District. A further impact on the historic district would result from the continuing visual intrusion of the temporary housing in the Boys Town and Huff House areas. The intensity of the adverse impact would be reduced by documenting resources as stipulated in the 1999 Programmatic Agreement, and by ensuring that designs for new construction were compatible with historic settings and architecture. However, continued deterioration would be considered a local, long-term, moderate, adverse impact.

Table IV‑4 summarizes the impacts of Alternative 1 on each of the contributing buildings and structures within the Camp Curry Historic District. Because the historic district would also be affected if no action were taken on the nonhistoric buildings and structures within the district, these impacts are also summarized in the table.

Table IV‑4 Alternative 1 Historic Resources and Impacts
Alternative 1 Components	Alternative 1 Impacts
A. Historic Buildings or Structures
§      Camp Curry Post Office (currently Curry Village registration building)	§      Continue use as a registration building §      Inefficient operation due to undersized facility §      Continued deterioration and resultant loss of historic fabric, particularly due to overuse
§      Curry Village registration building (currently Lounge)	§      Continue use as a lounge §      Ongoing deterioration of historic fabric
§      Wood cabins-with-bath (Bungalows) §      Wood cabins-without-bath §      Stoneman Lodge	§      Continue historic use as guest accommodations §      Ongoing deterioration of historic features
§      Historic Cottages (Huff House, Tresidder Residence, Mother Curry Bungalow, Cottage 819, and Bungalow 90A/B)	§      Continue use as employee housing §      Not in compliance with the Yosemite Valley Plan §      Heavy use accelerates damage to and deterioration of historic fabric
§      6 Restrooms in tent cabin areas (not addressed in the Yosemite Valley Plan)	§      Continue historic use as restrooms for tent cabin guests
§      2 comfort stations and bicycle rental building near existing ice rink (not addressed in the Yosemite Valley Plan)	§      Retain comfort stations for continued historic use as public restrooms §      Retain bicycle rental building for current use
§      Tent cabins	§      Retain all guest tent cabins in Curry Village in their present historic configuration §      Continue National Park Service policy of cyclical maintenance and replacement §      Not in compliance with the Yosemite Valley Plan
§      Camp Curry entrance sign	§      Retain the historic symbol of Curry Village at its historic location §      Continued deterioration of sign and surrounding environment
§      Transformer in Curry Village bungalow area (not addressed in the Yosemite Valley Plan)	§      Retain functioning transformer in its historic location §      Visually intrusive element in historic setting
§      Storage structure in Curry Village bungalow area (not addressed in the Yosemite Valley Plan)	§      Retain structure in its historic location
§      Stoneman Bridge	§      Retain Stoneman Bridge in place for continued vehicle use §      Not in compliance with the Yosemite Valley Plan (calls for pedestrian use or possible removal)
B. Nonhistoric Buildings or Structures
§      Amphitheater	§      No new amphitheater outside Curry Village §      Continuation of interpretive events in their historic location in Curry Village §      Continued conflict between amphitheater events and Curry Village outdoor dining and gathering spaces
§      Ice rink	§      Retain ice rink and attendant skate rental facility at present location §      Present ice rink facility is an unattractive feature along Curry Village Road §      Not in compliance with the Yosemite Valley Plan
§      Grocery store	§      No expansion of grocery store
§      Service area (maintenance, housekeeping, employee cafeteria)	§      No changes to maintenance, housekeeping, and employee cafeteria §      Not in compliance with the Yosemite Valley Plan §      Current housekeeping and maintenance facilities are inadequate, and service area is not separated from public areas
§      Curry Village employee housing	§      Retain all existing employee housing in Curry Village §      Not in compliance with the Yosemite Valley Plan §      Temporary housing visually intrudes on historic district §      Employees are housed in historic cabins, resulting in accelerated deterioration due to overuse

 Curry Orchard

No concerted effort would be made to protect and preserve Curry Orchard, other than salvaging cuttings and establishing representative plants at an appropriate conservation facility outside the park. The eventual loss of this resource would constitute a local, long-term, moderate, adverse impact to the Valleywide cultural landscape. However, documenting the orchard according to stipulations of the 1999 Programmatic Agreement would provide a historical record of the resource, thereby reducing the intensity of the adverse impact from moderate to minor.

Short-Term Impacts

The short-term impacts of Alternative 1 on historic resources would be the continuation of ongoing deterioration and the general intrusion of current management practices. With no new projects, there would be no additional short-term impacts on the historic district.

Summary of Alternative 1 Impacts. Under the No Action Alternative, historic properties and contributing cultural resources would be managed and protected under current policies. General deterioration would be expected to continue, resulting in a long-term adverse impact on the historic district. The existing ice rink complex would continue to be an intrusive visual element in the Village. The transformer in the bungalow area would also be visually intrusive. Occupancy of historic buildings by employees and the presence of temporary employee housing within the historic district would continue to have an adverse impact on the district as a whole. The lack of separation between housekeeping and maintenance areas and guest accommodations would also continue to adversely affect the historic district. Finally, the eventual loss of Curry Orchard would have an adverse impact on the Village. Impacts to individual features would result in a local, long-term, moderate, adverse impact to the overall character of the Camp Curry Historic District and the entire project area. The intensity of the adverse impact would be reduced by documenting resources as stipulated in the 1999 Programmatic Agreement.

Cumulative Impacts

Cumulative impacts on historic resources are based on analysis of past, present, and reasonably foreseeable future actions in Yosemite Valley and elsewhere in the park in combination with potential impacts of this alternative. The previous designation of the Camp Curry Historic District, implementation of the Yosemite Area Regional Transportation System and the Yosemite Valley Shuttle Stop Improvements, and the potential establishment of the Yosemite Valley Cultural Landscape Historic District are actions that, taken together with the implementation of this alternative, would cumulatively affect the historic resources within the project area. With the continuation of current park management policies and implementation of mitigation stipulated in the 1999 Programmatic Agreement, the cumulative projects would result in a long-term, minor, adverse impact on historic resources.

The continued maintenance of historic resources, absent the rehabilitation measures proposed by the Yosemite Valley Plan, while adversely affecting the historic district, would not change the magnitude of the cumulative impact. Alternative 1, in combination with the cumulative projects, would result in a long-term, minor, adverse impact on historic resources.

Impairment

There would be no change in the general management and maintenance of historic resources under Alternative 1. Continued maintenance would occur in accordance with established programs intended to preserve sensitive historic resources. The mitigation provided in these programs would ensure that historic resources would not be impaired for future generations.

Section 106 Summary

Under regulations of the Advisory Council on Historic Preservation (36 Code of Federal Regulations 800.9) addressing the criteria of effect and adverse effect, the National Park Service finds that the continuation of current park operations, including repairs and maintenance, would have the potential to adversely affect significant historic properties.

These historic properties consist of contributing elements of the Curry Village Historic District, the Yosemite Valley Archeological District, ethnographic resources, and Yosemite Valley historic cultural landscape features. Two archeological sites situated within or in the vicinity of the Upper Pines Campground, another site with historic and prehistoric components situated in the Lower Pines Campground, and five sites with surface and subsurface constituents in the vicinity of Curry Village may continue to be affected by ongoing operational and maintenance activities, as well as direct and indirect effects of future development, vandalism, visitor access, and natural processes. Two identified ethnographic village sites and portions of the three ethnographic gathering areas located within the area of potential effect would continue to sustain adverse effects from continuing visitor use, and maintenance of existing campground and visitor facilities. This alternative would have no effect on historic buildings or structures individually listed on the National Register of Historic Places. Historic elements of the Curry Village Historic District would continue to suffer adverse effects from deterioration and overuse of individual buildings and structures and association with nonhistoric structures within Curry Village.

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 resources would be avoided wherever possible, but in instances where avoidance or preservation could not be achieved, appropriate mitigation would be implemented. Procedures could involve data recovery carried out in accordance with the Programmatic Agreement to retrieve important information from the disturbed resources. To resolve any adverse effects to traditional cultural properties, park staff would consult with culturally associated American Indian tribes under the 1999 Programmatic Agreement and cooperative agreement for traditional uses. Adverse effects to historic resources would be mitigated through Historic American Buildings Survey/Historic American Engineering Record documentation, interpretation, and/or salvage and reuse of historic elements.

Social Resources
Scenic Resources
Analysis

Under the No Action Alternative, the amount of intrusion into Yosemite Valley views would not change from existing conditions. Some scenic features would continue to be obstructed by traffic along roads and other development in Yosemite Valley. The degree of obstruction or impact would continue to depend upon the vantage point of the visitor. Maintenance of existing utility infrastructure would occur in B‑scenic and C‑scenic areas. Construction activities would likely have short-term adverse impacts on scenic resources. Alternative 1 would not be expected to adversely impact landscape character, access to important viewpoints, or visibility of viewpoints.

Curry Village

No new development would occur at Curry Village, and existing visual conditions would remain. Stoneman Meadow, located north of the main Curry Village development, would continue to be bisected by Southside Drive. This highly scenic meadow, designated as A-scenic, is noted for its quality views. The view of Glacier Point (one of the 11 significant visual landmarks within the park) from Curry Village would continue to be obstructed. Unchecked growth of non-native vegetation in Curry Village would continue to obstruct views within and from the Village. Loss of the aging fruit trees of Curry Orchard would continue, exposing the parking lot and thus adversely affecting both the view from Glacier Point and local views from Curry Village and Stoneman Meadow. The continued obstruction of quality views would result in a local, long-term, minor, adverse impact to scenic resources. Maintenance of existing utility infrastructure in Curry Village could affect some Valley views resulting in a local, short-term, minor, adverse impact to scenic resources.

Campgrounds

Many of the campsites destroyed during the 1997 flood were never removed and are an eyesore for those visiting the project area. These abandoned and degraded campsites would remain under the No Action Alternative, resulting in a local, long-term, minor, adverse impact to scenic resources.

The South Camp area would remain relatively undeveloped, providing foreground wooded views but no distant views. Upper Pines Campground would continue to provide limited views because of the steep-sloping Valley wall to the south. Lower Pines Campground would continue to contain abandoned and degraded campsites, resulting in a local, long-term, minor, adverse impact to scenic resources. Maintenance of existing utility infrastructure in the campgrounds could affect some views resulting in a local, short-term, negligible, adverse impact to scenic resources.

Summary of Alternative 1 Impacts. Under the No Action Alternative, the amount of intrusion into Yosemite Valley views would remain as it is today. Some scenic features would continue to be obstructed by the intrusion of vegetation into the viewshed, resulting in a local, long-term, minor, adverse impact to scenic resources. The degree of obstruction or impact would continue to depend upon the vantage point of the visitor. Under the No Action Alternative, campsites abandoned after the 1997 flood would continue to degrade, resulting in a local, long-term, minor, adverse impact on scenic resources. Utility maintenance activities would result in a local, short-term, negligible to minor, adverse impact on 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 river corridor or in the immediate project vicinity.

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, moderate, 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 and can be seen from or within the Merced River corridor (e.g., the Eagle Creek Merced River Ecological Restoration Project, Merced River Plan, and implementation of the Yosemite Valley Plan). The Merced River Plan prescribes the restoration of degraded areas of the Merced River corridor, resulting in a local, long-term, major, beneficial impact on scenic resources.

Reasonably foreseeable projects that would have an adverse effect on scenic resources include development-related projects (e.g., construction of lodging at Yosemite Lodge pursuant to the Yosemite Valley Plan). The local, long-term, adverse effects of these reasonably foreseeable projects would be related to the potential introduction of new structures and/or infrastructure that would intrude into views of important scenic resources within, or viewable from, the Merced River corridor. The cumulative projects within and in the vicinity of the Merced River corridor 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 and improving the health of ecosystems within Yosemite Valley.

Under Alternative 1, the long-term, minor, adverse impact from the continued degradation of campsites abandoned after the 1997 flood would be overshadowed by the improvements to scenic resources throughout the Valley, and would not change the magnitude of the cumulative impact. Alternative 1 and the cumulative projects would result in a local, long-term, major, beneficial impact on scenic resources in Yosemite Valley, due to the overall emphasis on restoring disturbed or developed land to natural conditions and improving the health of ecosystems within Yosemite Valley.

Impairment

Alternative 1 would result in a local, long-term, minor, adverse effect on scenic resources due to the retention of degraded campsites and continued obstruction of high-quality views from Curry Village. The short-term adverse effect of this alternative on scenic resources would be primarily localized and would not be considered severe. Therefore, Alternative 1 would not impair scenic resources for future generations.

Park Operations and Facilities
Analysis

Under Alternative 1, existing utilities, facilities, infrastructure, demand, and management in the project area would remain as they are today. The National Park Service Division of Facilities Management would continue to manage electric, water, and sewer infrastructure and service. Solid waste and recycling services would continue to be carried out by the National Park Service Roads and Trails Branch of the Division of Facilities Management and Yosemite Concessioner Service following existing management and practices.

Maintenance of utilities in the project area would be localized and would result in a local, long-term, moderate, beneficial impact on park utilities because of the improved service following the necessary repairs. Utility repair activities could require temporary disruption to services, resulting in a local, short-term, minor, adverse impact.

Summary of Alternative 1 Impacts. Alternative 1 would not change the demand and maintenance of utilities, solid waste, and recycling in the project area. The performance of required maintenance activities would result in a local, short-term, minor, adverse impact to utility services. The resulting improvements to service would result in a local, long-term, moderate, beneficial impact on park utilities.

Cumulative Impacts

Cumulative impacts on utilities and solid waste and recycling services in and around the project area 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 utilities, solid waste, or recycling in the project area.

Implementation of the Yosemite Valley Plan would cause a slight increase in demand on utilities and solid waste and recycling services throughout the park, resulting in a regional, long-term, minor, adverse impact on utilities, solid waste, and recycling. Throughout Yosemite Valley, removal, construction, and relocation of a number of employee housing units and other park facilities would result in significant changes to utilities infrastructure. Relocation of a large number of park employees currently residing in Yosemite Valley to out-of-Valley housing areas would result in a local, long-term, moderate to major, beneficial impact by reducing demand on utilities in Yosemite Valley. However, relocation of existing facilities would require construction of additional utility lines, resulting in a local, short-term, moderate, adverse impact.

The Lower Yosemite Fall Project and Discovery View Scenic Overlook Vault Toilet Installation would result in minor increases in utility infrastructure and service requirements, resulting in a local, long-term, minor, adverse impact on utilities. Implementation of several ecological restoration and facilities renovation and rehabilitation projects would temporarily disrupt utility services in some areas of Yosemite Valley during construction, as well as remove or abandon outdated or unused utility infrastructure. The temporary interruption to utility services during construction would result in a local, short-term, negligible to minor, adverse impact, while removal or abandonment of outdated or unused utility infrastructure would result in a local, long-term, minor, beneficial impact on utilities.

Implementation of the East Yosemite Valley Utilities Improvement Plan would substantially benefit utility infrastructure and service throughout Yosemite Valley, resulting in a long-term, major, beneficial impact on utilities. Utility infrastructure improvements would include the construction of consolidated utility corridors and would address demand and service reliability requirements. Construction of the new infrastructure would, however, require temporary interruptions to service in some areas, resulting in a short-term, minor to moderate, adverse impact on utilities.

Overall, the past, present, and reasonably foreseeable future actions would have a local, long-term, moderate, beneficial cumulative impact because of the utility infrastructure improvements throughout the Valley. Alternative 1 would continue to maintain existing utility infrastructure, but would not increase utility services, which, while adverse, would not affect the magnitude of the cumulative impacts. The cumulative impacts, in combination with Alternative 1, would result in a local, long-term, moderate, beneficial impact on utilities.

Impairment

Alternative 1 would result in a short-term, minor, adverse impact to utilities in the project area and a long-term, negligible, adverse impact on the maintenance and operation of the utility infrastructure. However, these impacts would not impair park resources for future generations.

Transportation Planning
Analysis

The No Action Alternative would maintain existing transportation facilities and visitor travel patterns in the project area as well as travel conditions and patterns to the project area from other areas. Traffic volumes would increase, and parking demand would continue to exceed available parking supply. Many visitors would not be able to find parking near their destinations, and many visitors would park in roadside spaces. This congestion would continue to affect all visitors, regardless of travel mode, because bicyclists, regional transit, tour buses, and private autos would share the same roadways.

High traffic volumes within Yosemite Valley, along with inadequate parking and visitor confusion, would continue to create congestion during the peak season. Excess vehicle circulation would be common, as visitors seek the best routes for their destination and search for limited parking spaces. Excess vehicle circulation and congestion would continue between Curry Village and Yosemite Lodge. The intersection near Curry Village would remain highly congested. Traffic congestion would continue to cause delays for visitors in private vehicles, leading to increased vehicle emissions, and disruptions to the operation of the Valley shuttle system.

Curry Village

Alternative 1 would not change existing traffic circulation patterns or parking supply. Parking for day visitors and overnight guests would be unrestricted. Visitors to Curry Village would continue to experience congestion at the entrance roadway and insufficient parking to serve visitor demand. Visitors would continue to park in scattered lots and along roadsides. Traffic congestion would continue on Southside Drive, especially from vehicle recirculation to find parking. Conflicts between vehicles and pedestrians would continue to take place when pedestrians cross parking areas and roads to reach Curry Village attractions. Ongoing maintenance and upgrading of existing utilities could require temporary rerouting of traffic during construction. These conditions would result in a local, long-term, moderate, adverse impact. The construction mitigation measures identified in Chapter II would be implemented to reduce construction-related traffic impacts.

Campgrounds

Parking and access to the campgrounds would not be substantially altered under the No Action Alternative. No new construction would occur in the campgrounds, although maintenance to existing utility infrastructure would take place. The construction activities could require rerouting or temporary closure of campground serving roadways, resulting in a local, short-term, minor, adverse impact to traffic circulation.

Summary of Alternative 1 Impacts. With the No Action Alternative, existing roadway network and parking opportunities would remain unchanged. Visitors would continue to drive to the project area for overnight and day-use activities, increasing traffic congestion. Congestion and crowded parking conditions throughout the project area would continue and probably worsen under the No Action Alternative. The continued congestion and shortage of parking supply throughout the project area would result in a local, long-term, moderate, adverse impact. Utility maintenance activities would temporarily increase construction traffic on access roadways related to worker and material transport to construction sites, resulting in a local, short-term, minor, adverse impact to traffic circulation.

Cumulative Impacts

Cumulative impacts to transportation 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 impact, when combined with this alternative, is determined largely by whether such projects would affect transportation facilities or traffic circulation in the project area.

Under Alternative 1, while existing traffic and parking conditions would continue in the project area, other improvements provided in the Yosemite Valley Plan would be implemented, including the Yosemite Area Regional Transportation System. 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 reduce automobile congestion and limit 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, resulting in a local, long-term, major, beneficial impact to traffic flow, access, and circulation.

Construction of some of the reasonably foreseeable projects planned or approved within Yosemite Valley, such as the Curry Village Employee Housing, Lower Yosemite Fall, and Yosemite Lodge Area Redevelopment projects, could result in a local, short-term, adverse impact 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, such as the El Portal Road Improvement Project (the segment from Cascades Diversion Dam to Pohono Bridge) could also result in trip delays. The intensity of the adverse effect 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 reasonably foreseeable projects would result in a local, short-term, minor to moderate, adverse impact to traffic flow.

The cumulative projects would have a local, long-term, major, beneficial impact on transportation conditions in Yosemite Valley. Construction activities associated with the cumulative projects, however, would reduce the intensity of the beneficial impact to a minor or moderate level in the short term. The adverse impact associated with the continuance of existing congestion through Curry Village under Alternative 1 would reduce the overall benefit from other improvements to traffic and pedestrian circulation throughout the Valley; therefore, Alternative 1 would affect the magnitude of the cumulative impact. Alternative 1 and the cumulative projects would result in a local, long-term, minor, beneficial impact on transportation conditions in Yosemite Valley.

Impairment

Alternative 1 would not have a long-term impact on traffic circulation or safety and thus would not impair park resources for future generations.

Visitor Experience
Analysis

Under Alternative 1, the occasional heavy congestion, lack of parking, low reliability of the transportation system, and traffic impacts on recreation areas would continue to affect the visitor experience. Increases in visitation to Yosemite Valley would increase impacts to the visitor experience due to crowding, longer delays for access, and a lack of campsites.

Under Alternative 1, access to Yosemite Valley would remain unrestricted, and traffic congestion, air quality, and noise would continue to affect the visitor experience in the project area. Amenities for visitors – including food service, restroom, and shower facilities – would not be sufficient to meet visitor demand, and visitors would continue to experience crowding at food service areas and limited access to shower facilities. Traffic congestion would continue to occur during peak hours on Southside Drive.

Maintaining the utility infrastructure, would involve construction activities throughout the project area. Construction activities could temporarily alter vehicle and pedestrian circulation, occupy parking areas, generate noise and dust, and limit or block visitor access to certain areas. Construction activities would also introduce additional traffic into the project area. Construction activities would be localized and temporary, resulting in a short-term, minor to moderate, adverse impact to the visitor experience.

Curry Village

Day visitors would continue to have access to day-use parking in Curry Village. Traffic congestion would increase on heavy-use days, and spontaneity would be reduced. Overnight wilderness users would continue to park in the wilderness parking area in Curry Village. The number of accessible parking spaces would continue to be insufficient for the growing demand, creating inconvenience for disabled visitors. Disabled visitors would continue to have difficultly navigating in Curry Village due to dispersed accessibility. The continuance of these conditions would result in a local, long-term, minor, adverse impact to the visitor experience.

Employees and visitors would continue to share the cafeteria in Curry Village, which is currently undersized and overcapacity. Visitors would continue to have long waits in the cafeteria line, although mainly during peak hours of the peak visitation season. Light pollution would continue due to outdated lighting infrastructure used to illuminate lodging areas; food, retail, and other service facilities; and operations support facilities. The continuance of these conditions would result in a local, long-term, major, adverse impact to the visitor experience.

Campgrounds

No changes to the campgrounds within the project area would occur under Alternative 1, and there would continue to be no group campsites available in the project area. Restoration of campsites destroyed by the 1997 flood also would not occur. No shower facilities would be constructed in the campgrounds, and campers would continue to go to Curry Village to shower. Except during low-use periods, views of automobiles, buses, and scattered parking lots and facilities, along with vehicle-related noise and odors, would remain part of most recreational experiences. The continuance of these conditions would result in a local, long-term, major, adverse impact to the visitor experience.

Summary of Alternative 1 Impacts. Inadequate service for the visitor population would continue under Alternative 1. Access and navigation in Curry Village would remain confusing to visitors, due to multiple access roads. Visitation levels would likely increase, compounding problems with congestion and parking. Due to congestion and lack of available parking, many visitors would be forced to spend extra time circulating to find parking, instead of enjoying the area’s features. The continuance of these conditions would result in a local, long-term, minor to moderate, adverse impact to the visitor experience.

Cumulative Impacts

Cumulative effects to the visitor experience 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 the visitor experience near and within the project area.

Visitation to the park is expected to increase due to projected increases in population within the state, including a doubling of population within the nearby Central Valley areas, although future visitation would be influenced by more than just the local population. If visitation continues to increase and private vehicles remain the primary mode of travel in the park, problems with traffic congestion, access, and parking would continue.

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

The Merced River Plan would have a beneficial cumulative impact 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 impact on the visitor experience due to expanded recreational opportunities in Yosemite Valley and improved transit service that would distribute visitors to more park destinations. Alternative 1 would allow continued congestion and inadequate visitor services in Curry Village and the campgrounds. Because of the high level of visitation to this area, the continuance of these adverse conditions would affect the magnitude of the cumulative impact. Alternative 1 and the cumulative projects in Yosemite Valley would result in a local, long-term, minor, beneficial impact on the visitor experience because of the expanded recreational opportunities in Yosemite Valley and improved transit service.

Impairment

Impacts of Alternative 1 to the visitor experience include occasional heavy traffic congestion; lack of visitor parking, especially for visitors with disabilities; difficulty in navigating through the development areas; low reliability of the transportation system; light pollution; and traffic impacts on recreation areas. These conditions would contribute to erosion of the visitor experience and opportunities for enjoyment of the park. As such, Alternative 1 would impair park resources for future generations.

Socioeconomics
Analysis

Visitor Population

Under Alternative 1, there would be no change to the day-visitor and overnight visitor populations. The number of lodging and camping facilities would remain the same. There would be no significant changes to the park’s facilities and operations that would appreciably affect the visitor population. Alternative 1 would result in a local, long-term, negligible, adverse impact on the visitor population.

Regional Economics

There would be no change to visitor spending behavior under Alternative 1, because no changes to the types of goods and services available to visitors would occur. Additionally, no new construction would occur under Alternative 1, and thus no construction spending impact on the regional economy. Because no changes in visitor spending or construction spending are projected, there would be no change in park employment under Alternative 1 and no employment impact on the regional economy. Alternative 1 would result in a local, long-term, negligible, adverse impact on regional economics.

Summary of Alternative 1 Impacts. Alternative 1 would not change the visitor population and regional economics of the area. The No Action Alternative would have a regional, long-term, negligible, adverse impact on local communities, visitor population, and regional economies.

Cumulative Impacts

Cumulative socioeconomic effects are based on an analysis of past, present, and reasonably foreseeable future actions in the region in combination with potential impacts 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 impact on the regional economy are related to construction activity, including that proposed under the Yosemite Valley Plan; Eagle Creek Merced River Ecological Restoration; Ecological Restoration of Flood-Damaged Campgrounds; the El Portal Road Improvement Project; Cascades Diversion Dam Removal; Happy Isles Fen Habitat Reclamation Project; Happy Isles to Vernal Fall Trail Reconstruction; Lower Yosemite Fall Project; Replacement/Rehabilitation of Yosemite Valley Main Sewer Line; Yosemite Lodge Area Redevelopment; Yosemite Valley Shuttle Bus Stop Improvements; and the East Yosemite Valley Utilities Improvement Plan. Private development projects such as the Yosemite Motels Expansion just outside 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 the 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 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 in the long term. The