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Affected Environmen

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CHAPTER 3: AFFECTED ENVIRONMENT AND
 

ENVIRONMENTAL CONSEQUENCES
 

INTRODUCTION

This chapter describes the existing environment that could be affected by implementation of the

alternatives in the Mariposa Grove FEIS. It also analyzes the impacts that could result from

implementation of each of the alternatives. The information is structured around 14 general topics,

which were derived from National Environmental Policy Act (NEPA) requirements, the purpose and

need of the project, and input gathered during internal and public scoping. These topics are:

•	 Vegetation

•	 Wildlife

•	 Special­status species

•	 Wetlands

•	 Hydrology and water quality

•	 Soils

•	 Air quality and climate change

•	 Soundscapes

•	 Historic structures

•	 American Indian traditional cultural resources

•	 Archaeological resources

•	 Visitor experience and recreation (including public safety and transportation)

•	 Park operations

•	 Energy use and sustainability

NEPA IMPACT ANALYSIS

This chapter provides a scientific and analytic basis for comparisons among the alternatives, in

accordance with direction in NEPA and National Park Service (NPS) policy. The analysis examines

both direct and indirect impacts that could result from the alternatives based on the context,

duration, intensity, and type of potential impact, and whether the impacts would be cumulative. The

following guidelines are applicable to all the analysis topics, with the exception of selected cultural

resources and rare, threatened, and endangered species (see Assessment of Effects on Special­Status

Species and Historic Properties, below).

Context. The context of the impact considers whether the impact would be site­specific, local,

parkwide, or regional. For the purposes of this analysis, local impacts would occur within Mariposa

Grove or South Entrance. Regional impacts refer to Yosemite National Park in conjunction with 

adjacent private and public lands in the western Sierra Nevada.

Duration. The duration of an impact considers whether the impact is short term or long term.

•	 Short­term impacts are generally as long as the construction period (including demolition,

materials staging, renovation or repair of existing facilities, establishment of relocated

facilities, rehabilitation of historic properties, and preparation of areas for ecological

restoration). Impacted resources would return to or resume their previous conditions

Final Environmental Impact Statement 3­1 October 2013

Chapter 3: Affected Environment and

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Introduction

Restoration of the Mariposa Grove of Giant Sequoias

following these activities. In this analysis, short­term impacts may last from a few days for

site­specific activities, to up to six months for historic rehabilitation or extensive

construction.

•	 Long­term impacts last well beyond the construction period, and the resources may not

resume to their previous condition. Permanent impacts could last many years. Successful

ecological restoration is an example of a long­term impact.

Intensity. Intensity refers to the degree or magnitude of impacts on a resource. Each impact is

identified as negligible, minor, moderate, or major, in conformance with the definitions provided

under each impact topic.

Type. The type of impact considers whether the impact is beneficial or adverse. Because the

definition of beneficial varies by resource topic, a discussion is provided separately for each resource

topic.

•	 Beneficial: A positive change in the condition or appearance of the resource, or a change that

moves the resource toward a desired condition.

•	 Adverse: A change that moves the resource away from a desired condition or detracts from

its appearance or condition. Because the definition of adverse varies by resource topic, a

discussion is provided separately for each resource topic.

IMPACT TOPICS CONSIDERED BUT DISMISSED

The impact topics in this section originate from a list that the Council on Environmental Quality

(CEQ) developed to ensure consideration of specific topics during preparation of an environmental

impact statement. The items on the CEQ list that the NPS considered but dismissed are discussed

below. The remaining items on the CEQ list are impact topics addressed in this chapter.

Night Sky. This project is not expected to have an impact on night skies. All new design and

construction, or substantial modifications to structures, would conform to the Yosemite Lighting

Guidelines (NPS 2011j) and avoid impacts on night sky (see Appendix E, Mitigation Measures).

Therefore, this topic was dismissed from further analysis.

Museum Collections. The Yosemite Museum collection would not be affected by the proposed

project. Therefore, this topic was dismissed from further analysis.

Growth­Inducing Impacts. The alternatives proposed in the Mariposa Grove FEIS are unlikely to

foster additional growth in the region surrounding the park. A growth­inducing project would

directly or indirectly:

•	 Foster economic or population growth or additional housing

•	 Remove obstacles to growth

•	 Tax community services or facilities to such an extent that new services or facilities would be

necessary

•	 Encourage or facilitate other activities that cause significant environmental effects

The regional economy in the vicinity of Yosemite National Park is likely to remain the same under all

the alternatives proposed in the Mariposa Grove FEIS, as all the alternatives would accommodate

existing visitor use levels. In the long­term, growth­inducing impacts would be similar to those of

Final Environmental Impact Statement 3­2 October 2013

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Introduction

Restoration of the Mariposa Grove of Giant Sequoias

current conditions, with regional communities providing employment and services similar to current

levels (see Socioeconomics, below). Therefore, this topic was dismissed from further analysis.

Socioeconomics. A socioeconomic analysis for this purpose would evaluate potential impacts on the

social environment, visitor populations, and the regional economy. The social and economic

environments of the surrounding communities are primarily affected by changes in visitor levels,

visitor spending, park and concessioner employment, and park and concessioner spending in the

regional economy. Impacts on Yosemite National Park and the primary concessioner are addressed

in the Mariposa Grove FEIS under Chapter 3, Park Operations.

There would be no measureable changes expected in park­wide annual visitation (estimated

3,951,393 people in 2011) as a result of the Mariposa Grove FEIS. The goal of the plan is to

accommodate the current visitor use levels of the Mariposa Grove area. Concessioner employment

associated with the tram, which is eliminated under Alternatives 2 and 3, is a nominal amount of

employment and revenue generated within the park. While the gift shop would be removed under all

action alternatives, new visitor services would be provided at the South Entrance area (Alternatives 2

or 4) or at Grizzly Giant (Alternative 3). These services would include visitor information,

educational, and other sales items, and it is anticipated that there would be little to no net

employment change under the action alternatives.

Overall, the project is expected to result in negligible impacts on the socioeconomic environment,

visitor populations, and the regional economy. Similarly, the project is not expected to result in

growth­inducing impacts either regionally or in nearby communities; this is a consideration under

the California Environmental Quality Act. Therefore, socioeconomics was dismissed from further

analysis.

Prime and Unique Farmlands. There are no agricultural lands within Yosemite National Park.

There would be no direct or indirect effects on downstream agricultural lands. Therefore, this topic

was dismissed from further analysis.

Land Use. None of the Mariposa Grove FEIS alternatives would fundamentally affect land use in the

Mariposa Grove area. Proposed changes at South Entrance and the Grizzly Giant area of the Grove

would be consistent with the overall land use pattern: a combination of undeveloped open space,

wilderness, and visitor use and recreation. Therefore, this topic was dismissed from further analysis.

Environmental Justice. An environmental justice analysis determines whether a proposed action

would have “disproportionately high and adverse human health or environmental effects on

minority populations and low­income populations.” The NPS and other federal agencies have

determined that a disproportionately high and adverse effect on minority and low­income

populations would be an adverse effect that (1) is predominately borne by a minority population

and/or a low­income population, or (2) will be suffered by the minority population and/or lowincome population and is appreciably more severe or greater in magnitude than the adverse effect

that will be suffered by the nonminority population and/or non­low­income population.

Potential adverse effects identified in an environmental justice analysis include air, noise, and water

pollution; soil contamination; destruction or diminution of aesthetic values; destruction or

disruption of community cohesion and economic vitality; displacement of public and private

facilities and services; increased traffic congestion; and exclusion or separation of minority or lowincome populations from the broader community. Of particular concern is the effect on property

acquisition and displacement of people.

Final Environmental Impact Statement 3­3 October 2013

Chapter 3: Affected Environment and

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Introduction

Restoration of the Mariposa Grove of Giant Sequoias

No aspect of any alternative in the Mariposa Grove FEIS would result in disproportionately high and

adverse human health or environmental effects on minority or low­income populations. Any

restriction on travel or access to any area of the park that might result from the alternatives would be

equally applied to all visitors, regardless of race or socioeconomic standing. The one exception to

this policy is that use by traditionally associated American Indian tribes and groups would continue

to be managed independently of general public recreational use.

Employee housing decisions are not expected to result in destruction or disruption of community

cohesion and economic vitality, displacement of public and private facilities and services, increased

traffic congestion, and/or exclusion or separation of minority or low­income populations from the

broader community.

CUMULATIVE IMPACTS

The environmental consequences analysis includes a discussion of the cumulative impacts, which 

considers the implementation of the alternatives in the context of other past, current, or proposed

projects in the area. A cumulative impact is described in the regulations developed by the Council on

Environmental Quality, as follows:

A “Cumulative impact” is the impact on the environment which results from the incremental

impact of the action when added to other past, present, and reasonably foreseeable future actions

regardless of what agency (Federal or non­Federal) or person undertakes such other actions.

Cumulative impacts can result from individually minor but collectively significant actions taking

place over a period of time. (CEQ regulation 1508.7)

The cumulative impacts addressed in this analysis include past and present projects, as well as

planning or development activity being implemented or planned for implementation in the

reasonably foreseeable future. Appendix B lists the past, present, and reasonably foreseeable actions

considered in the cumulative impacts analysis. These cumulative actions are evaluated in

conjunction with the impacts of an alternative to determine whether they would have additive effects

on a particular resource or value.

IMPAIRMENT

In addition to determining the environmental consequences of the alternatives, NPS Management

Policies 2006 (NPS 2006) and NPS Director’s Order 12 require analysis of potential effects to

determine if actions would impair park resources and values. Following public review and after

conclusion of the no­action period, the evaluation for determination of impairment for the selected

alternative will be documented in an attachment to the Record of Decision for the final Mariposa

Grove EIS.

ASSESSMENT OF EFFECTS ON SPECIAL­STATUS SPECIES AND HISTORIC PROPERTIES

The effect of proposed actions on special­status species and historic properties are determined

under procedures of the Endangered Species Act (Section 7) and the National Historic Preservation

Act (NHPA) (Section 106), respectively. For species listed under the Endangered Species Act, the

NPS, in consultation with the U.S. Fish and Wildlife Service (USFWS), must determine if the action

will have “no effect,” “may effect, not likely to adversely affect,” or “may effect, likely to adversely

affect” listed species or their habitats. Impact assessments on historic properties (i.e. cultural

resources listed on or determined eligible for listing on the National Register of Historic Places

[National Register]) under Section 106 of NHPA must determine whether there is “ no effect on

historic properties,” “no adverse effect,” or “adverse effect.” Some cultural resources impact

determinations may be characterized as necessary to fulfill NEPA requirements. Specific

methodologies are described in respective sections of this chapter.

Final Environmental Impact Statement 3­4 October 2013

Chapter 3: Affected Environment and

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Natural Resources: Vegetation

Restoration of the Mariposa Grove of Giant Sequoias

NATURAL RESOURCES

VEGETATION

Affected Environment

About 1,700 plant species, subspecies,

and varieties and numerous

bryophytes and lichens occur in

Yosemite National Park (NPS 2010b).

The major ecological zones of the

Sierra Nevada form readily apparent,

large­scale, north/south elevation

bands along the axis of the Sierra

Nevada. Major east/west watersheds

that dissect the Sierra Nevada into

steep canyons form a secondary

pattern of vegetation. Yosemite

National Park includes six major

ecological zones: west slope oakchaparral, west slope lower mixed

conifer, west slope California red fir

belt, west slope subalpine conifer, and

alpine, (Keeler­Wolf et al. 2012). The

Mariposa Grove of giant sequoias

occurs between 5,700 and 6,700 feet in

the west slope mixed conifer zone

(figures 3­1 and 3­2). The study area

around the South Entrance is at

approximately 5,150 feet elevation.

Figure 3­1 – The Big Trees

Final Environmental Impact Statement 3­5 October 2013

Chapter 3: Affected Environment and

Environmental Consequences
Natural Resources: Vegetation 

Restoration of the Mariposa Grove of Giant Sequoias 

Figure 3­2 – Schematic of Vegetation by Elevation within Yosemite National Park

Source: National Park Service 1980a

Mariposa Grove 

The Mariposa Grove of Giant Sequoias covers an area of approximately 222 hectares (550 acres). 

This is the boundary of the grove of trees and includes most of the roads, trails, and facilities (NPS 

2011a). It is the largest of the three groves of giant sequoia within Yosemite National Park. Giant 

sequoias occur in the giant sequoia/sugar pine alliance, which is one of three upland forest types in 

the Grove along with the white fir – Sierran mixed conifer alliance and California red fir associations 

(figure 3­3). The giant sequoia/sugar pine alliance is dominated or co­dominated by giant sequoia 

(Sequoiadendron giganteum). Associated tree species include sugar pine (Pinus lambertiana), Jeffrey 

pine (P. jeffreyi), white fir (Abies concolor), ponderosa pine (P. ponderosa), and incense cedar 

(Calocedrus decurrens). Two oak species, California black oak (Quercus kelloggii) and canyon live oak 

(Q. chrysolepsis), and Pacific dogwood (Cornus nuttallii) also occur in some locations. Pockets of 

shrub species include whitethorn ceanothus (Ceanothus cordulatus), greenleaf manzanita 

(Arctostaphylos patula), bush chinquapin (Chrysolepis sempervirens) and huckleberry oak (Quercus 

vaccinifolia) (NPS 2011a). Nine vegetation associations that occur in the Mariposa Grove partly 

define the types of wildlife habitat. These are described in the Wildlife section and include: Sierran 

mixed conifer, white fir, montane hardwood conifer, montane hardwood, ponderosa, montane 

chaparral, wet meadow, barren and Jeffrey pine. Wetlands within the Grove are discussed in the 

Wetlands section of Chapter 3. Figure 3­3 presents vegetation types of the Mariposa Grove, South 

Entrance, and much of southwestern Yosemite National Park and adjacent lands. 

Final Environmental Impact Statement  3­6  October 2013 

Chapter 3: Affected Environment and 

Environmental Consequences 
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Figure 3­3 – Vegetation Alliances and Associations of Southwestern Yosemite National Park

Final Environmental Impact Statement 3­7 

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Natural Resources: Vegetation

Restoration of the Mariposa Grove of Giant Sequoias

The adult giant sequoia population in Mariposa Grove is roughly divided into two subpopulations, a

lower subpopulation in the lower Grove area and an upper subpopulation in the upper Grove area.

Detailed information about the number of adults, juveniles, saplings, and seedlings, as well as their

spatial relationship with roads, burned areas, wetlands, and other geographic features is contained in

the document Giant Sequoias of the Mariposa Grove: Population Status and Trends: 2011 (NPS 2011a).

The relevant key findings of this reference and other relevant reports are discussed below.

Many factors contribute to the current conditions of plant communities in the Mariposa Grove.

Giant sequoia mixed coniferous forest typically requires recurring, moderately intense fires to

maintain healthy ecosystem function (NPS 2011b). The past century of fire suppression has resulted

in increased density and proportion of shade tolerant tree species such as white fir and incense

cedar, increased accumulation of dead and down woody debris, reduced regeneration of giant

sequoia and pines, and reduced density of shrubs (Weatherspoon 1986). Native diseases, insects and

pathogens also shape plant communities. Annosus root disease (Fomes annosus), primarily spread by

tightly spaced white fir, occurs in the Grove and can contribute to failure of mature giant sequoia

(Piirto 1994). Outbreaks of the native Douglas­fir tussock moth (Orgyia pseudotsugata) periodically

occur, causing some mortality in white fir. In addition, snow removal, road repairs, and utilities

maintenance regularly damage or kill vegetation. An average of 30 hazard trees are cut annually to

protect Mariposa Grove parking areas, buildings, and the Grove road (NPS 2011a).

Of the many factors important for successful giant

sequoia germination and establishment, the most

influential are fire and hydrology. Fire is critical for

successful giant sequoia reproduction since it fulfills

several requirements for regeneration. Fire prepares a

seed bed by consuming surface fuels, including downed

trees and dense understories; it provides a nutrient rich 

layer of ash on the soil surface;, and it opens up the

canopy to provide ample light for emerging seedlings

(figure 3­4) (Harvey et al. 1980).

Topography and groundwater levels also influence the

spatial distribution of giant sequoias, with most adults

and juveniles occurring in concave to flat areas

(figure 3­5). Soil moisture, important in all life stages of

the giant sequoias, is especially critical at the

germination stage. In the Mariposa Grove, recruitment

of giant sequoia appears to be tied to wetlands for

several size classes. Juvenile giant sequoias are strongly

associated with the mapped wetlands: 54 percent are

within wetland boundaries, and approximately

81 percent are within 100 feet of wetlands. Saplings also

are correlated with wetlands, with 42 percent

established within wetlands, and 68 percent within 100­feet of wetlands (NPS 2011c). Based on these

associations, it is likely that altered hydrology and impacts on wetlands affect recruitment of giant

sequoias.

Figure 3­4 – Burned Area in Mariposa Grove

Final Environmental Impact Statement 3­8 October 2013

Chapter 3: Affected Environment and

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Natural Resources: Vegetation

Restoration of the Mariposa Grove of Giant Sequoias

Figure 3­5 – Location of Giant Sequoias in the Mariposa Grove

(Note age class distribution and proximity to wetlands particularly in the lower Grove area.)

Final Environmental Impact Statement 3­9 October 2013

Chapter 3: Affected Environment and

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Natural Resources: Vegetation

Restoration of the Mariposa Grove of Giant Sequoias

Giant sequoias have expansive but shallow root systems that provide stability for the tree’s enormous

mass; rather than succumbing to insects or pathogens, toppling or fire are the primary causes of giant

sequoia mortality. The root systems are vast and extend to as much as 200 feet from mature trees

(NPS 2011c). A majority of mature giant sequoias in the Mariposa Grove are found close to existing

roads. An analysis of the spatial arrangement of mature trees in relation to the paved roads in the

Grove found the mean distance from road centerline to tree centerline was 180 feet, with a range of

6.5 to 817 feet; 68 percent of all mature trees lie within 175 feet of road centerlines, which is well

within the root zones of the giant sequoias (NPS 2011c). Because the root systems are so large and

extend under roads, the roads themselves and the maintenance thereof may negatively impact the

majority of adult giant sequoias. Most direct and indirect road impacts are adverse, primarily the

cutting of roots during road construction and maintenance, as well as bole and bark damage from

road maintenance and passing vehicles. In addition, similar to roads, hiking trails are suspected to

have negative impacts (albeit less so than roads) on giant sequoias; where hikers could cause

considerable soil erosion, exposing giant sequoia roots and potentially contributing to tree failure.

However, there is no empirical evidence to substantiate anecdotal impacts that hiking trails influence

the longevity of giant sequoias. Seventy percent of all adult trees are within 200 feet of trails, which is

within the maximum estimated root zone distance for adult giant sequoias (NPS 2011c).

A large number of giant sequoia seedlings and saplings are found near roads. However, as younger

trees mature, the roads may begin to exert the negative impacts described in the previous paragraph.

Climate change may play an important role in the future of Mariposa Grove ecology. The Mariposa

Grove is relatively dry and is close to the elevation where the dominant form of precipitation transitions from snow to rain, suggesting that it may be more vulnerable to changes in precipitation relative

to other groves (York 2011). As the climate warms, snow melt, a major source of soil­water recharge

in giant sequoia groves, is likely to come earlier in the spring than at present, potentially prolonging

the summer drought that is characteristic of the Sierra’s Mediterranean­type climate (York 2011).

Non­native Species. The Mariposa Grove has a relatively low level of infestation of non­native plant

species. However, invasive plant populations in the Mariposa Grove are a concern because of their

potential to spread into more remote wilderness locations. Invasive species mapping in Mariposa

Grove identified six priority species including Himalayan blackberry (Rubus discolor), cut­leaf

blackberry (R. laciniatus), bull thistle (Cirsium vulgare), common mullein (Verbascum thapsus),

foxglove (Digitalis purpurea), many­flowered tobacco (Nicotiana acuminata var. multiflora), and

velvet grass (Holcus lanatus) (NPS 2012a).

Fire Management. Yosemite National Park fire managers began prescribed burning in the Mariposa

Grove in 1971, and nearly the entire Grove has burned at least once over the past 40 years, with most

areas having burned more than once since then (figure 3­6). During this period, the repeated prescribed fires have greatly reduced the density of fuels and trees within the Grove. However, forests

surrounding the Mariposa Grove have not been managed intensively through the years. Much of the

forest surrounding the Grove has not burned in the last 100 years. Historically, these forests burned

roughly every 9 years prior to Park Service management. As more time passes, there is a greater

build­up of fuels and greater departure from the historic fire return frequency, which is described by

the fire return interval departure (FRID). Most of the surrounding forests have a FRID of 4 or

higher. The unburned forest and high concentration of surface fuels, including downed trees, as well

as dense understories in forests surrounding the Grove leave it vulnerable to a high­intensity fire in

the future (NPS 2011b) (figure 3­7).

Final Environmental Impact Statement 3­10 October 2013

Chapter 3: Affected Environment and

Environmental Consequences
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Figure 3­6 – Fire History of the Mariposa Grove

Final Environmental Impact Statement 3­11 

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Figure 3­7 – Fire Return Interval Departure for the Mariposa Grove and Surrounding Forest

Final Environmental Impact Statement 3­12 

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Natural Resources: Vegetation

Restoration of the Mariposa Grove of Giant Sequoias

South Entrance

Upland Vegetation. The dominant vegetation at the South Entrance includes two forest types, one

co­dominated by white fir and sugar pine, with a smaller proportion of incense cedar and Jeffrey

pine, and the other co­dominated by ponderosa pine and incense cedar, with a smaller proportion of

California black oak and canyon live oak (NPS 2011a). The South Entrance also includes a small

pocket of ponderosa pine and incense cedar forest.

This area was heavily logged in the early 1900’s by the Madera Sugar Pine Company and, therefore,

consists of second growth smaller diameter trees. In 1909, the company’s logging activities and land

holdings so worried Wawona hotelier E.P. Washburn that he expressed concern for the scenic

preservation of the drive between Wawona and the Grove (Greene 1987).

Wetlands within the South Entrance area are discussed in the later Wetlands section.

Non­native Species. The South Entrance has a low level of infestation of non­native plant species,

with conditions and treatment similar to those described above for the Mariposa Grove.

Fire Management. The FRID of most of the area immediately surrounding the South Entrance is

greater than 4. An exception is a small section of FRID 2 to the west of the entrance station, which 

burned in the 1980s and again in 2003. Due to fire suppression, the area has an increased stem

density of more shade­tolerant species such as white fir and incense cedar. This species mix was

encouraged by the logging of pines, which occurred in the late 1800s. Fire suppression has also

resulted in an increased stem density of small­diameter trees, and higher concentrations of dead and

downed wood. Hazard trees are removed annually for safety and fuels management.

Environmental Consequences

Impact Assessment Methodology

Determination of the significance of potential impacts on vegetation is based on the context,

duration, type, and intensity of impact that could result from actions associated with implementation

of an alternative under consideration. For the alternatives evaluated in this Mariposa Grove FEIS,

vegetation impact assessment was based on a qualitative analysis of project area vegetation and the

potential effects anticipated as a result of ongoing maintenance, construction, or rehabilitation. The

qualitative analysis also considered areas that were likely to be affected by selective road and

infrastructure improvements, relocation, and/or development, as well as other aspects of the project.

The essential qualities of native plant communities include their spatial extent, integrity

(consistency) of species composition, repeated association with natural features, and vigor in terms

of the growth and reproduction of constituent species. Actions that reduce/degrade these qualities

are considered to have adverse impacts; actions that preserve or restore these qualities have

beneficial impacts. The proposed action alternatives have a variety of different components that

would affect vegetation, including ground disturbance and vegetation removal, alteration of drainage

patterns, changes in vehicle and pedestrian traffic volumes and patterns, impacts on roadside areas,

and active revegetation and restoration measures.

Impact Intensity Level Definitions

Negligible – Native vegetation would not be affected, or impacts would not be measurable.

Final Environmental Impact Statement 3­13 October 2013

Chapter 3: Affected Environment and

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Natural Resources: Vegetation

Restoration of the Mariposa Grove of Giant Sequoias

Minor – Impacts on native vegetation would be detectable however restoration would minimize or

rectify adverse impacts, and would be relatively simple to implement and would have a high 

probability of success.

Moderate – Impacts on native vegetation would be readily apparent and restoration would be

necessary to reduce or rectify adverse impacts.

Major – Impacts on native vegetation would be readily apparent and would substantially change the

biological value of the native plant community in the context of the park or Region. Restoration

would be necessary to reduce or rectify adverse impacts, and its success could not be guaranteed.

Alternative 1: No Action

Construction Impacts. Plant community qualities would be unchanged under Alternative 1 because

concessioner services maintenance and park management would remain as is. No actions such as

removal or renovation of existing infrastructure, improvement of hydrologic flow, project­specific

prescribed fire treatments, soil decompaction, and construction of facilities would be implemented.

Operations­related Impacts. Under Alternative 1, current park resource management programs

such as prescribed burning and invasive species management would continue. Existing road design

and alignment, impermeable surfaces (including parking facilities), insufficient or plugged culverts,

and trails would continue to impair hydrologic connectivity, infiltration, subsurface flow, and

retention of available water within the Mariposa Grove which could degrade native plant

communities. Specific facilities and structures impacting hydrologic flow/process include:

(1) 41 roadway drainage culverts with diminished function or capacity, (2) 2.9 acres of impervious

surface in the lower Grove area and 0.31 acre at the South Entrance, (3) 8.4 acres of existing road

through Mariposa Grove and (4) about 3.5 acres of existing trails with Mariposa Grove. As a result,

48.6 acres of surface water runoff is diverted from natural flow patterns within the Mariposa Grove

and 88.5 acres of surface water runoff is diverted from the Mariposa Grove. Road and parking area

stormwater runoff would continue to discharge waterborne pollutants directly into the giant sequoia

ecosystem. Leaks from the chlorinated­water pipeline through the upper Grove area would continue

to affect soil saturation and plant communities along the water line.

Tram operations, employee parking, and visitor use off trails would continue to damage giant

sequoia root systems and plant communities by compacting soils in local areas. Compacted soils

from pedestrian traffic along trails would continue sheet erosion of litter, duff, and topsoil; the

indirect removal of this protective covering could expose roots and would change conditions

required for giant sequoia seedling survival. Damage to trees, such as stripping off protective bark,

pedestrian trampling of the roots, and collection of seed cones, would continue in high­use areas.

The impact would be minimized with proper fencing, educational programs and signage, and regular

management and patrols of these areas. Narrow points along the Mariposa Grove Road would

continue to result in scrapes that damage giant sequoia as drivers attempt to avoid vehicle collision.

Fire management practices would include prescribed burning in and near the Grove and would favor

a long­term change in plant community composition away from shade­tolerant and fire­intolerant

species. Prescribed fire also would help in the reproductive success and recruitment of giant sequoia

within the Grove. However, the fuels outside the immediate Mariposa Grove vicinity, particularly to

the south and west, could continue to grow, increasing the possibility of a catastrophic crown fire,

which could threaten the survival of the giant sequoias at the Grove.

Impact Significance. Alternative 1 would be expected to have major adverse impacts on vegetation

within the Mariposa Grove that are not widespread but that exist as long­term impacts.

Final Environmental Impact Statement 3­14 October 2013

Chapter 3: Affected Environment and

Environmental Consequences
     

               

   

         

                         

                           

                       

                             

         

                     

                         

                         

                   

                       

                               

                       

                         

                             

                         

                         

                             

                         

                         

                               

                             

                                 

           

                               

                   

             

                     

                       

                 

                         

                         

                           

                     

                             

                       

                 

                         

                             

                     

                         

                        

                             

                           

                           

                         

                           

Natural Resources: Vegetation

Restoration of the Mariposa Grove of Giant Sequoias

Conclusion. Park infrastructure would not be improved and existing adverse impacts on vegetation

would continue, including damage to giant sequoia roots systems, vehicle scraping of giant sequoia,

and impaired hydrologic function within the Mariposa Grove. Commercial tram service, visitor

access, and current fire management practices would continue at existing levels, and would result in

adverse impacts on vegetation resources.

Cumulative Impacts. Cumulative impacts on vegetation discussed in this section consider the past,

present, and reasonably foreseeable future actions in the Yosemite region in conjunction with the

potential effects of Alternative 1(No Action). In the past 150 years, activities associated with 

urbanization and regional population growth (e.g., building and dam construction, utility

installation, road and bridge building, intensive logging, stormwater discharge) contributed to direct

loss of native plant communities in the Yosemite region. Impacts range from direct loss of native

vegetation (e.g., replaced with structures); alteration of natural patterns (e.g., fire suppression around

structures, the introduction of night light); increased erosion and sedimentation (e.g., during grading

activities, overuse of trails); to indirect losses such as changes in water flows that sustain vegetative

habitat. Other activities, particularly fire suppression, changed the nature of existing native plant

communities. These past impacts correlate with the spread of invasive plants in California. While

fewer than 10 percent of the 1,000­plus (Hickman 1993) non­native plant taxa that have established

in California are recognized as serious threats, the spread of non­native plants has dramatically

changed the landscape of the Yosemite region. For example, grasses native to the Mediterranean

region are now a dominant understory plant in the Sierra Nevada foothills. Changes in vegetation are

likely to increase in intensity or rate as the climate continues to change (D’Antonio 2004; Mutch 

2007). The overall effect of these past actions and future trends on vegetation in the Yosemite region

has been adverse, long­term, and major.

Current and future plans and projects in the region would have beneficial and adverse impacts on

vegetation (Appendix B). The Parkwide Invasive Plant Management Plan Update, Comprehensive

Ecological Restoration Projects, Wawona Meadow Restoration Project, and ecological restoration

elements of the Draft Merced and Tuolumne Wild and Scenic River Comprehensive Management Plans

would result in long­term beneficial impacts on plant communities. Activities associated with the

Fire Management Plan/Operational Fire Management Plan and U.S. Forest Service fuels reduction

projects would greatly reduce the threat of large high­severity catastrophic fires, and reduce the

potential for vegetation type conversion. Within the Mariposa Grove area, prescribed burns will

continue to take place periodically; the last burn was in 2008. The Wilderness Stewardship Plan could

contribute watershed­scale protection to native plant communities, depending on the outcome of

the final plan. Past and future actions would have a long­term moderate beneficial effect on

vegetation.

There would be adverse impacts on vegetation associated with the current South Entrance Station

Kiosks Replacement project, the Scenic Vista Management Plan, the Environmental Education

Center, and future actions associated with new development proposed in the Draft Merced River

Plan and Draft Tuolumne River Plan, due to the localized loss of vegetation. Site­specific adverse

effects on vegetation could be short­term (during construction) and long­term (direct displacement

of vegetation). These plans include mitigation measures to preserve the genetic integrity of native

plants and reduce the risk of importation and spread of invasive plants.

In summary, past impacts on vegetation in the region have been adverse, long­term, and major.

Present and foreseeable future actions would contribute to reversing the adverse impacts of past

actions in the region to moderate adverse impacts. Past, present, and future impacts, in conjunction

with the localized, long­term major adverse impacts on vegetation under Alternative 1 (No Action),

would result in a long­term moderate adverse impact on vegetation in the Yosemite region.

Final Environmental Impact Statement 3­15 October 2013

Chapter 3: Affected Environment and

Environmental Consequences
     

               

   

         

           

                             

                           

                         

                     

                       

                       

     

                   

                   

                         

                               

                                 

                                   

                                 

                                 

                               

                               

                           

                               

                           

                             

                                 

                       

                             

                             

      

                           

                             

                               

                               

                           

                             

                           

       

                         

                             

                               

                            

                               

                                   

                       

                       

                             

                             

                

Natural Resources: Vegetation

Restoration of the Mariposa Grove of Giant Sequoias

Alternative 2: South Entrance Hub (Preferred Alternative)

Alternative 2 would remove the gift shop and commercial tram operation from the Mariposa Grove,

and reduce the amount of lower Grove parking while expanding and relocating primary visitor

parking to the South Entrance, making the South Entrance the departure point for visitors accessing

the Grove. Rehabilitation and restoration actions, such as improvement of hydrologic flow, projectspecific prescribed fire and hazardous fuel reduction treatments, soil decompaction, and improved

way­finding and protective barriers that would reduce off­trail pedestrian use, would be components

of this alternative.

Construction­related Impacts. Adverse impacts on vegetation from Alternative 2 within the

Mariposa Grove would include vegetation removal associated with construction of new

infrastructure and the removal of existing buildings and infrastructure. This alternative includes the

option to construct a newly aligned vehicle bridge at the entrance curve to Mariposa Grove, which

would occur within 50 feet of three mature giant sequoias. This, plus the re­route of Mariposa Grove

Road out of the wetland in the lower Grove area, would potentially impact up to 35 seedling or

juvenile giant sequoias; these trees may be removed or transplanted if less than 15 inches diameter at

breast height. This estimate is based on a visual assessment of the general location of the re­route,

and during the design phase tree locations would be surveyed and avoided to the extent possible.

While the construction of the new vehicle bridge would impact giant sequoia roots, the removal of

the existing road alignment through the wetland would reduce impacts on roots of other giant

sequoia in the vicinity over the long term. Shrubs and groundcover would be removed or salvaged

during construction to clear and restore roadside ditches. Removal of the vehicle bridge at the

entrance curve, vault toilets, and trailhead at the lower Grove parking area; extending the existing

footbridge in the lower Grove area; and reducing the size of the lower Grove parking area would

result in changes to plant community composition and structure. In addition, narrowing and

converting the existing paved road past the Grizzly Giant to a hardened trail and developing

accessible pathways in the lower Grove area and at Grizzly Giant would also alter plant community

composition and structure.

Construction of the roundabout at the Wawona Road – Mariposa Grove Road intersection would

result in some vegetation removal, though in a previously disturbed area. It is estimated that the

construction of the roundabout could result in the removal of between 15 and 20 non­giant sequoia

trees. Clearing of vegetation and grading would occur along the existing Washburn Road and in an

undisturbed area south of the Mariposa Grove Road and east of the picnic area during construction

of the proposed pedestrian trail from the South Entrance to the lower Grove area. Areas where

buildings and infrastructure are removed would be restored; indirectly this could result in improving

the plant community function.

Leach fields may be constructed at the South Entrance and lower Grove area contingent upon

further soil surveys and analysis. The potential options for leach field locations plus the allocation of

a 100 percent replacement set­aside area would result in the removal of non­giant sequoia trees. No

giant sequoia habitat would be affected, although the types of trees impacted would vary slightly.

The leaking water line would be repaired or replaced, and the water tank and chlorination unit

would be moved to a site below the museum in the upper Grove area. Repair of the water

distribution system would reduce the extent of or eliminate hydrophitic vegetation currently

supported by water line leaks. Additional discussion of potential wetland impacts associated with 

Alternative 2 is provided in the Wetlands section. Selected limbing or tree removal would be

conducted at Wawona Point to restore the panoramic vista. This could help move these areas

towards a more natural plant community composition and structure.

Final Environmental Impact Statement 3­16 October 2013

Chapter 3: Affected Environment and

Environmental Consequences
     

               

   

         

                           

                           

                   

                   

                             

                         

                             

                               

                                 

        

                     

                         

               

                   

                           

                             

                             

                                 

            

                         

                   

               

                       

                         

                         

                               

                               

                             

                

                           

                             

                         

                             

                                   

                         

                         

                         

                               

                                 

                       

         

                   

                     

Natural Resources: Vegetation

Restoration of the Mariposa Grove of Giant Sequoias

Adverse vegetation impacts at the South Entrance would result from construction of a new parking

area with primary access and visitor support facilities. During construction activities plants may be

broken, crushed, or completely removed. Revegetating areas temporarily impacted by construction

would restore natural plant community composition and structure. South Entrance would require

clearing between 5.0 acres and 6.0 acres of non­giant sequoia habitat. The net footprint after

landscape restoration at the South Entrance build­out would equal 4.72 acres of non­giant sequoia

habitat, including 3.13 acres of impervious surfaces. A new trail from South Entrance to lower Grove

area would impact a total of 0.66 acre, including 0.42 acre along old Washburn road alignment,

0.21 acre of new trail across non­giant sequoia habitat, and approximately 0.03 acre of the new trail

across giant sequoia habitat.

Impact Significance. Under Alternative 2, construction is expected to have site­specific, long­term

minor adverse and beneficial impacts on vegetation within the Mariposa Grove, and moderate longterm adverse impacts on non­Sequoia vegetation at the South Entrance.

Restoration­related Impacts. Beneficial impacts on vegetation under Alternative 2 include (1) a

1.44 acre­reduction of impermeable surfaces within the lower Grove area due to removal of the

lower Grove parking lot, gift shop, and commercial tram staging area and operations, (2) restoration

of 0.43 acre of giant sequoia habitat from the removal of trails with Mariposa Grove, and

(3) restoration of 2.11 acres of giant sequoia habitat from the narrowing of road or conversion of

roads to trails within Mariposa Grove.

Restoration after the removal of impermeable surfaces would provide for giant sequoia habitat

restoration, soil decompaction, and increased water infiltration. Improvements to roadway drainage

culverts with diminished function or capacity, and implementation of sustainable stormwater

strategies would improve hydrologic connectivity, restore subsurface flows, and retain water within

the Mariposa Grove which would restore giant sequoia habitat, and could improve survival and

seedling recruitment. Two areas (21.1 acres and 27.5 acres, respectively) where water is being

diverted from its natural course within Mariposa Grove and one area (88.5 acres) where water is

being diverted outside of Mariposa Grove would be restored. Alternative 2 would restore 1.0 acre of

wetlands due to ecological restoration activities within the lower Grove area and removal of trails

and road narrowing in the upper Grove area.

Over the long­term, removal of infrastructure and elimination of the commercial tram service from

the Mariposa Grove would protect and restore giant sequoia habitat and could improve the health of

mature sequoias and aid in seedling recruitment. Project­wide, the net change in development under

Alternative 2 would equal the addition of 0.74 acre in developed area which is comprised of

3.98 acres net reduction in of developed area within the Grove plus 4.72 acres of new development at

the South Entrance. The removal of facilities and roads would improve water infiltration and could

reduce impacts on vegetation by removing pavement that covers roots. Human­induced impacts that

change the environment (e.g., impermeable surfaces that alter soil moisture content) and indirectly

affect the vigor and reproduction of giant sequoia would be reduced. Removal of facilities and roads

could reduce the need for hazard tree removal in some areas. Hazard tree removal would continue to

ensure visitor safety and infrastructure protection where appropriate. Appendix D provides the

restoration plan for the Grove.

Impact Significance. Alternative 2 is expected to have site­specific, long­term, major beneficial

impacts and minor adverse impacts on vegetation within the Mariposa Grove.

Final Environmental Impact Statement 3­17 October 2013

Chapter 3: Affected Environment and

Environmental Consequences
     

               

   

         

                       

                                 

                           

                             

                             

                           

                           

                               

                           

                               

                       

                           

                  

                             

                             

                     

                          

                   

                           

           

                     

                         

                             

                       

                       

                     

                 

                 

                           

                       

                               

                         

                 

         

                             

                                 

                               

                               

                           

                               

                 

                           

             

Natural Resources: Vegetation

Restoration of the Mariposa Grove of Giant Sequoias

Operations­related Impacts. Narrowing the existing road past the Grizzly Giant into a hardened

trail and converting the southern portion of the upper Grove loop road to a pedestrian trail would

reduce traffic and operational activities in the Mariposa Grove and reduce adverse impacts on

vegetation. Adverse impacts on vegetation would be introduced from vehicle and visitor use at the

new Grove parking area at the Grizzly Giant. The South Entrance would experience an increase in

visitation and operational use resulting in greater adverse impacts on vegetation. Day use activities

would continue to cause vegetation impacts in the Mariposa Grove. Pedestrian traffic would include

direct impacts on the trails from soil compaction, erosion, and root exposure that could affect the

health of giant sequoia; but much of this can be minimized through clear trail delineation. Vandalism,

such as stripping off bark from giant sequoia, could continue in high­use areas. But the impact would

be minimized with proper fencing, educational programs and signage, and regular management and

patrols of these areas. The addition of way­finding signs and improving visitor orientation could

reduce off­trail use, indirectly improving plant community composition and structure.

Mechanical thinning and prescribed fire planned south and west of the Grove up to the park’s

boundary with the Sierra National Forest would mitigate risks of a catastrophic crown fire reaching

the Mariposa Grove. Implementing these fire management actions would improve plant

communities and return areas to the pattern of natural plant composition and structure.

Impact Significance. Alternative 2 operations are expected to have site­specific, long­term minor

beneficial and adverse impacts on vegetation within the Mariposa Grove, and minor adverse impact

on vegetation at the South Entrance.

Conclusion. Construction activities within the Mariposa Grove would result in some temporary

adverse impacts on vegetation. There would be long­term major beneficial impacts from the

termination of commercial tram services and the removal of developed areas that would result in

3.98­acres of ecological restoration within Mariposa Grove. Restoration of hydrological flows would

have long­term beneficial impacts on vegetation within the Mariposa Grove. The second growth 

vegetation at the South Entrance would experience moderate long­term adverse impacts from

greater use and development of parking and other facilities.

Cumulative Impacts. The regional past, present, and reasonably foreseeable projects affecting

vegetation would be the same as those under Alternative 1 (No Action)—an overall long­term

moderate adverse impact on vegetation in the Yosemite region. These impacts, in conjunction with 

the long­term major beneficial impacts of Alternative 2 on vegetation in the Mariposa Grove, and the

long­term moderate adverse impacts on vegetation at the South Entrance, would result in long­term

moderate adverse impacts on vegetation in the Yosemite region.

Alternative 3: Grizzly Giant Hub

Alternative 3 would remove the commercial tram operation and build a new bypass road, including

two new bridges, and a new larger parking lot near the Grizzly Giant, outside of giant sequoia

habitat. This alternative would make the Grizzly Giant the primary departure point for visitors to the

Grove. The current South Entrance parking lot would remain as is, and the lower Grove parking lot

would be largely removed; ten ABAAS­compliant parking spaces would be provided in the lower

Grove area. Accessible pathways would be developed in the lower Grove area and at Grizzly Giant.

Rehabilitation and restoration actions, such as improvement of hydrologic flow, project­specific

prescribed fire and hazardous fuel reduction treatments, and soil decompaction would be similar to

those described under Alternative 2, South Entrance Hub.

Final Environmental Impact Statement 3­18 October 2013

Chapter 3: Affected Environment and

Environmental Consequences
     

               

   

         

               

                       

                           

                               

                                 

                       

                             

                                 

                               

                               

                             

                               

                         

                           

                             

                             

      

                           

                         

                           

                           

                  

                     

                           

     

                   

                             

                               

                                   

                         

                                   

                                 

                             

                 

                     

                 

                           

                         

                               

                           

                   

             

                       

                               

                           

                             

Natural Resources: Vegetation

Restoration of the Mariposa Grove of Giant Sequoias

Construction­related Impacts. Adverse vegetation impacts from Alternative 3 would include

vegetation removal associated with removal of existing infrastructure and construction of new

structures, including the bypass road, two new vehicle bridges, new parking facility and primary

access node at the Grizzly Giant Hub, flush toilets at the lower Grove parking area, extending the

existing footbridge in the lower Grove area, reducing the size of the lower Grove parking area to

include only ABAAS­compliant parking spaces, narrowing and converting the existing road surface

to a hardened trail. Construction of the newly aligned vehicle bridges south of the current road

would occur within 50 feet of one mature giant sequoia. While the new vehicle bridges would impact

giant sequoia roots, the removal of the existing road alignment and culverts would reduce impacts on

roots of other giant sequoia in the vicinity. Construction of the bypass road would impact about

2.2 acres of vegetation, primarily non­giant sequoia habitat but including 0.33 acre of giant sequoia

forest and 0.10 acre of raised crossings over wetlands. Construction activities for the bypass road and

new bridge structure would occur near existing mature giant sequoia, which could adversely impact

the root system. The Grizzly Giant Hub would require clearing approximately 5.61 acres of nongiant sequoia habitat and shrub lands. The net footprint after landscape restoration at the Grizzly

Giant Hub after build­out would equal 3.13 acres of non­giant sequoia habitat, including 2.92 acres

of impervious surfaces.

Adverse vegetation impacts from Alternative 3 at the Grizzly Giant area would include vegetation

removal associated with construction of a parking lot and vault toilet facilities. Adverse vegetation

impacts from Alternative 3 would be concentrated in different locations than under Alternative 1

or 2, because under Alternative 3 the South Entrance would remain unchanged and the primary

facility improvements would occur within the Grove at Grizzly Giant.

Impact Significance. Alternative 3 is expected to have site­specific, long­term moderate adverse

impacts on non­giant sequoia vegetation at the Mariposa Grove, and minimal adverse impacts on

vegetation at the South Entrance.

Restoration­related Impacts. Beneficial impacts on vegetation from Alternative 3 include (1) a

2.38­acre reduction of impermeable surfaces within the lower Grove area, (2) restoration of 0.58 acre

of giant sequoia habitat due to the removal of trails with Mariposa Grove, and (3) restoration of

2.79 acres of giant sequoia habitat due to the narrowing of road or conversion of roads to trails

within Mariposa Grove. Project­wide, the net change in development under Alternative 3 would

result in the addition of 0.50 acre in developed area which is comprised of 5.75 acre net reduction in

of developed area within the Grove plus 6.25 acres of new development at the Grizzly Giant arrival

area and new bypass road. Restoration after the removal of impermeable surfaces would provide for

giant sequoia habitat restoration, soil decompaction, and increase water infiltration. Improvements

to roadway drainage culverts with diminished function or capacity, and implementation of

sustainable stormwater strategies would improve hydrologic connectivity, restore subsurface flows,

and retain water within the Mariposa Grove which would restore giant sequoia habitat, and could

improve survival and seedling recruitment. The amount of area where hydrologic connectivity is

being restored would be similar to Alternative 2. Alternative 3 would restore 1.0 acre of wetlands

within the lower Grove area. Appendix D includes the restoration plan for the Grove.

Impact Significance. Alternative 3 is expected to have site­specific, long­term major beneficial

impacts on vegetation within the Mariposa Grove.

Operations­related Impacts. Narrowing portions of the existing road into a hardened trail and

converting the southern portion of the upper Grove loop road to a pedestrian trail would reduce

traffic and operational activities in the Mariposa Grove and reduce adverse impacts on vegetation.

Removing the existing road from the lower Grove area to the Grizzly Giant and routing operational

Final Environmental Impact Statement 3­19 October 2013

Chapter 3: Affected Environment and

Environmental Consequences
     

               

   

         

                             

                           

                         

                           

                     

                  

                 

                             

   

                     

                       

                           

                             

                         

                               

                           

              

                 

                           

                       

                             

                             

               

                   

                             

                           

                           

                     

                       

              

                 

                             

                         

                           

                  

                     

                             

                   

                                 

                             

                               

                                   

                         

Natural Resources: Vegetation

Restoration of the Mariposa Grove of Giant Sequoias

use to the bypass road would reduce operational­related impacts on vegetation at the lower Grove

area compared to Alternative 2 but would introduce disturbance into new non­giant sequoia habitat

areas. Shifting the primary arrival node to Grizzly Giant would increase visitation and operational

use in that location resulting in greater indirect adverse impacts on vegetation from pedestrian

trampling and off­trail use. However, additional way­signing and day­use­related activities would

result in similar impacts on vegetation as Alternative 2.

Impact Significance. Alternative 3 operations would have site­specific, long­term minor adverse

impacts on vegetation within the Mariposa Grove, and moderate adverse impact on vegetation at the

Grizzly Giant.

Conclusion. Construction activities within the Mariposa Grove would result in long­term moderate

adverse impacts on non­giant sequoia vegetation associated with the construction of the bypass

road, parking area, and primary access facilities at Grizzly Giant Hub. Long­term beneficial impacts

would result from the termination of commercial tram services and the removal of developed areas

that would make 5.75 acres available for ecological restoration within the Mariposa Grove.

Alternative 3 would result in a net addition of 0.05 acre in developed areas project­wide after buildout. Overall, long­term beneficial impacts on vegetation are expected to be moderate within the

Mariposa Grove and negligible at the South Entrance.

Cumulative Impacts. The regional past, present, and reasonably foreseeable projects affecting

vegetation would be the same as those under Alternative 1 (No Action)—an overall long­term

moderate adverse impact on vegetation in the Yosemite region. These impacts, in conjunction with 

the long­term beneficial impacts of Alternative 3 in the Mariposa Grove, and the long­term adverse

impacts on vegetation near the Grizzly Giant and access road, would result in long­term moderate

adverse impacts on vegetation in the Yosemite region.

Alternative 4: South Entrance Hub with Modified Commercial Tram Service

Alternative 4 would maintain the commercial tram tour, but with a limited route and hours of

operation, while also relocating the majority of the parking to the South Entrance, making the South 

Entrance the primary departure point for visitors to the Grove. Numerous other rehabilitation and

restoration actions, such as improvement of hydrologic flow, project­specific prescribed fire and

hazardous fuel reduction treatments, soil decompaction, and improvement of visitor orientation and

interpretation, would be components of this alternative.

Construction­related Impacts. Adverse impacts resulting from construction of new facilities or

modification of existing infrastructure are expected to be similar to those described in Alternative 2.

However, construction of the modified T­intersection at the Wawona Road – Mariposa Grove Road

intersection would result in slightly different vegetation removal affecting between 5 and 10 trees,

though these impacts would occur in a previously disturbed area.

Impact Significance. Alternative 4 is expected to have site­specific, long­term minor adverse

impacts on vegetation within the Mariposa Grove and moderate adverse impacts on vegetation at the

South Entrance.

Restoration­related Impacts. Beneficial impacts on vegetation from Alternative 4 include (1) a

1.59 acre reduction of impermeable surfaces within the lower Grove area due to removal of the lower

Grove parking lot, gift shop, and commercial tram staging area and operations, (2) restoration of

0.02 acre of giant sequoia habitat from the removal of trails with Mariposa Grove, and (3) restoration

of 0.23 acres of giant sequoia habitat from the narrowing of road or conversion of roads to trails

within Mariposa Grove. Drainage and hydrologic improvements would be similar to those in

Final Environmental Impact Statement 3­20 October 2013

Chapter 3: Affected Environment and

Environmental Consequences
     

               

   

         

                             

                               

                                   

        

                   

             

                 

                         

                                 

                         

                     

                           

                   

                     

             

                     

                          

                             

                     

                       

                         

  

                 

                           

                       

                             

               

                           

                             

                           

                       

                         

          

                         

                             

                       

                           

                               

                       

                         

                         

Natural Resources: Vegetation

Restoration of the Mariposa Grove of Giant Sequoias

Alternative 2. Alternative 4 would restore 0.77 acre of wetlands within the lower Grove area. Projectwide, Alternative 4 would result in a net addition of developed areas of2.88 acres, which is comprised

of an estimated 1.84 acre net reduction in developed area within the Grove plus 4.72 acres of new

development at the South Entrance.

Impact Significance. Alternative 4 is expected to have site­specific, long­term major beneficial

impacts on vegetation within the Mariposa Grove.

Operations­related Impacts. Commercial tram operations would require keeping the existing road

width and improved road surfaces which would continue to impair giant sequoia root systems and

encroach on the ability of some sequoias to grow in diameter due to the proximity of asphalt. Road

stormwater runoff would continue to discharge waterborne pollutants directly into the giant sequoia

ecosystem. Commercial tram operations, employee parking, and visitor use would continue to

damage giant sequoia root systems. Narrow points along the Mariposa Grove Road would continue

to result in vehicle scraping the bark of giant sequoia.

Impact Significance. Alternative 4 is expected to have site­specific, long­term moderate adverse

impacts on vegetation within the Mariposa Grove.

Conclusion. Construction activities within the Mariposa Grove would result in some temporary

adverse impacts on vegetation. There would be long­term major beneficial impacts from the

removal of developed areas that would result in 5.98 acres of ecological restoration within Mariposa

Grove. Restoration of hydrological flows would have long­term beneficial impacts on vegetation

within the Mariposa Grove. The second growth vegetation at the South Entrance would experience

moderate long­term adverse impacts from greater use and development of parking and other

facilities.

Cumulative Impacts. The regional past, present, and reasonably foreseeable projects affecting

vegetation would be the same as those under Alternative 1 (No Action)—an overall long­term

moderate adverse impact on vegetation in the Yosemite region. These impacts, in conjunction with 

the long­term beneficial impacts of Alternative 4 in the Mariposa Grove, would result in moderate

adverse impacts on vegetation in the Yosemite region.

WILDLIFE

Affected Environment

Wildlife in the Mariposa Grove and South Entrance is diverse and abundant, reflecting the wide

range of Yosemite National Park habitats. The mixed conifer hardwood habitat type of the project

area adjacent to and surrounding the Mariposa Grove supports an especially rich diversity of wildlife

species. The mixture and interface of vegetation types provide complex forest structure with 

numerous ecological niches. The uniqueness of the Mariposa Grove supports a distinct assemblage

of wildlife species (NPS 2013a).

Park biologists reviewed park data (NPS 2013a) and used the California Wildlife Habitat

Relationships model to predict which wildlife species are likely to occur in and around the Grove

and South Entrance. Together, the Mariposa Grove and South Entrance are home to 78 different

reptile, amphibian, mammal, and bird species. Concentrated areas of human use in the Mariposa

Grove may have degraded habitat of some wildlife, especially in upper and lower Grove areas. Giant

sequoia stands within the Mariposa Grove are highly productive, structurally diverse habitats that

support a high number of wildlife species. In addition, introduced non­native species within the

Mariposa Grove and South Entrance have the potential to degrade habitat for wildlife. Wildlife

Final Environmental Impact Statement 3­21 October 2013

Chapter 3: Affected Environment and

Environmental Consequences
     

               

   

         

                             

         

   

                                 

                         

                       

                             

                     

                     

                       

                         

                     

                             

                   

                       

                       

                               

                                   

                           

                                 

                         

                 

    

                             

                         

                                 

                         

                                 

                       

                       

                 

                             

                               

                             

                 

                 

                 

                 

                 

                 

           

              

Natural Resources: Wildlife

Restoration of the Mariposa Grove of Giant Sequoias

species and their habitat requirements are reviewed in this section, along with the potential effect on

wildlife resources from the project alternatives.

Mariposa Grove

There are a total of nine vegetation types within the Mariposa Grove that are components of the

various wildlife habitats. These include Sierran mixed conifer, white fir, montane hardwood conifer,

montane hardwood, ponderosa, montane chaparral, wet meadow, barren, and Jeffrey pine (NPS

1997). The vegetation types present are Sierran mixed conifer forest and white fir forest; dominant

tree species in these communities include white fir (Abies concolor), giant sequoia (Sequoiadendron

giganteum), and sugar pine (Pinus lambertiana) (NPS 1997). Old­growth forest types provide habitat

for raptor species such as the California spotted owl (Strix occidentalis occidentalis) (California

species of special concern [CSC]) and northern goshawk (Accipiter gentilis) (CSC), as well as cavitydependent mammal species such as the Pacific fisher (Martes pennanti pacicica) (federal candidate

for listing [FC]/CSC) and various bat species. Less common forested types in the Mariposa Grove

include montane hardwood conifer, montane hardwood, ponderosa, and Jeffrey pine, which 

provide habitat for a variety of bird species, including the olive­sided flycatcher (Contopus cooperi)

(CSC), and bat species. Montane chaparral, the only shrub­dominated plant community, provides

habitat for a variety of mammal species and reptile species. Barren rock outcrops are present at

Wawona Point and provide valuable habitat for a variety reptiles and roost sites for a number of bat

species, including the western mastiff bat (Eumops perotis californicus) (CSC). Finally, a small amount

of wet meadow habitat is present in the Mariposa Grove and provides valuable habitat for a variety

of songbird species and amphibians such as the song sparrow (Melospiza melodia) and the Sierra

Nevada ensatina (Ensatina eschscholtzii plattensis). These vegetation communities are shown in

figure 3­8.

The Mariposa Grove is moderately developed, with a variety of paved roads and trails primarily

through the Sierran mixed conifer, montane hardwood conifer, and white fir habitats. In addition

there are two paved areas in the Sierran mixed conifer forest. The Grove experiences high levels of

pedestrian traffic from May through October, with use dissipating as one travels from the lower

Grove area to the upper Grove area, and on to Wawona Point. These conditions can affect wildlife

use patterns or condition wildlife to relatively high human activity levels. Park and concessioner

management practices, such as no­wildlife­feeding reminders for visitors, no camping or fires, and

bear­proof trash receptacles, have been implemented to discourage attractive nuisance conditions

for wildlife. The Grove’s proximity to wilderness may offer superior quality for some habitat types.

A high diversity of wildlife is present in the Mariposa Grove; a total of 72 wildlife species (including

special­status wildlife species) have been observed in the area. This diverse array of species includes:

eight amphibian and reptile species, such as the gregarious slender salamander (Batrachoseps

gregarious), northern alligator lizard (Elgaria coerulea), and northwestern fences lizard (Sceloporus

occidentalis occidentalis); 32 mammal species, such as black bear (Ursus americanus), bobcat (Lynx

rufus), mountain lion (Puma concolor), Douglas squirrel (Tamiasciurus douglasii), California ground

squirrel (Spermophilus beecheyi), and yellow­bellied marmot (Marmota flaviventris), plus a variety of

bat species; and 32 bird species, including Cooper’s hawk (Accipiter cooperii), golden­crowned

kinglet (Regulus satrapa), mountain chickadee (Poecile gambeli), mountain quail (Oreortyx pictus),

pileated woodpecker (Dryocopus pileatus), and western bluebird (Sialia mexicana) (NPS 2013a).

Final Environmental Impact Statement 3­22 October 2013

Chapter 3: Affected Environment and

Environmental Consequences
     

               

   

         

                               

   

                                       

   

                           

                       

                                 

                             

                     

                       

Natural Resources: Wildlife

Restoration of the Mariposa Grove of Giant Sequoias

Figure 3­8 – Vegetation as a Component of Wildlife Habitat in and Near the Mariposa Grove

Source: NPS 1997

Note: This map of park plant communities was used by biologists to predict habitat suitability for wildlife in the project

vicinity.

South Entrance

The South Entrance contains habitats similar to those at the Mariposa Grove and is dominated by

montane hardwood conifer. Dominant tree species within this community include ponderosa pine,

incense cedar, California black oak, and canyon live oak. These habitats are shown in figure 3­9. This

diversity of plant species creates a complex habitat structure that includes pure stands of conifers

interspersed with stands of broad­leaved trees, often with an understory of shrubs. This provides

habitat for a variety of bird and mammal species, as discussed below.

Final Environmental Impact Statement 3­23 October 2013

Chapter 3: Affected Environment and

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Natural Resources: Wildlife

Restoration of the Mariposa Grove of Giant Sequoias

Figure 3­9 – Vegetation as a Component of Wildlife Habitat in and Near the South Entrance

Source: NPS 1997

Note: This map of park plant communities was used by biologists to predict habitat suitability for wildlife in the project

vicinity.

The South Entrance is moderately developed, with a variety of paved roads and trails primarily

through the montane hardwood conifer and white fir habitats, and high year­round vehicle traffic

volumes along Wawona Road and the Mariposa Grove Road. There is one small paved area off of the

main road. Similar to the Grove environment, the abundance of vehicles and pedestrians can affect

wildlife use patterns or condition wildlife to relatively high human activity levels. Park and

concessioner management practices, such as no­wildlife­feeding reminders for visitors, no camping

or fires, and bear­proof trash receptacles, have been implemented to discourage wildlife from

becoming habituated to human food.

There is lower diversity of wildlife present in the South Entrance area than in the Mariposa Grove

area. Species observed include 10 mammal species, such as the black bear, bobcat, coyote (Canis

latrans), mule deer (Odocoileus hemionus), and western gray squirrel (Sciurus griseus); and five bird

species, such as the acorn woodpecker (Melanerpes formicivorus), Canada goose (Branta

canadensis), spotted owl, and western bluebird (NPS 2013a).

Final Environmental Impact Statement 3­24 October 2013

Chapter 3: Affected Environment and

Environmental Consequences
     

               

   

         

                               

                                   

                                 

                             

                             

                 

                                 

       

                             

                             

                             

        

     

                             

             

                                   

  

                             

                           

                             

                             

             

                               

                       

                           

                 

                               

                     

                           

       

                   

                         

                       

                       

           

                               

                     

                               

Natural Resources: Wildlife

Restoration of the Mariposa Grove of Giant Sequoias

Environmental Consequences

Impact Assessment Methodology

Determination of the significance of potential impacts on wildlife is based on the duration, type, and

intensity of impact; all are influenced by the scale (area) of impact. Impacts can be direct, i.e. an

immediate result of the action, or indirect, resulting from the action but occurring later in time or

removed from the location of direct physical impacts. Wildlife impact analysis was based on a

qualitative assessment of the project area and the impacts anticipated as a result of ongoing

maintenance, construction or rehabilitation. Quantitative analysis was conducted to determine areas

that were likely to be affected by selective roadside tree thinning and brush removal as well as other

aspects of the project.

Adverse impacts include those that would negatively affect the size, continuity, or integrity of wildlife

habitat, or result in unnatural changes in the abundance, diversity, or distribution of wildlife species.

Conversely, impacts were classified as beneficial if they would positively affect the size, continuity, or

integrity of wildlife habitat.

Impact Intensity Level Definitions

Intensity of impacts on wildlife was analyzed by determining the extent at which the proposed road

improvements would disturb wildlife and their habitat.

Negligible – Wildlife would not be affected, or impacts would not result in a loss of individual or

habitat.

Minor – Impacts on wildlife would be measurable or perceptible and local; however, the overall

viability of the population or subpopulation would not be affected and without further adverse

impacts the population would recover. Impacts on wildlife, such as displacement of nests or dens or

obstruction of corridors, would be detectable. If mitigation is needed to reduce or rectify adverse

impacts, it would be relatively simple to implement.

Moderate – Impacts would be sufficient to cause a change in the population or subpopulation (e.g.,

abundance, distribution, quantity, or viability); however, the impact would remain local. The change

would be measurable and perceptible, but the negative impacts could be reversed. Mitigation would

probably be necessary to reduce or rectify adverse impacts.

Major – Impacts would be substantial, highly noticeable, and could be permanent in their impact on

population or subpopulation survival without active management. Extensive mitigation would likely

be necessary to reduce or rectify adverse impacts, and its success could not be guaranteed.

Alternative 1: No Action

Under Alternative 1 current infrastructure, concessioner services and maintenance, and park

management would remain as is. No rehabilitation and restoration actions, such as improvement of

hydrologic flow and universal access, project­specific prescribed fire and hazardous fuel reduction

treatments, soil decompaction, and improvement of visitor orientation and interpretation, would be

implemented.

Operation­related Impacts. Disturbance from operations, recreations, and routine maintenance

affect wildlife using the habitats at the Mariposa Grove and in the surrounding areas. Types of

disturbance include noise, artificial light, human presence, automobile traffic, and other useassociated effects. Because of the level of disturbance that has been ongoing for 30 years, some

Final Environmental Impact Statement 3­25 October 2013

Chapter 3: Affected Environment and

Environmental Consequences
     

               

   

         

                             

                             

                         

                         

     

               

                 

                       

     

                         

                   

                             

                       

                     

                       

                         

                       

                   

                      

                               

                             

                         

                             

                           

                           

               

       

                               

                                 

                       

                           

                               

                               

                             

                               

                       

                         

                 

                             

           

                             

                     

           

                 

                         

Natural Resources: Wildlife

Restoration of the Mariposa Grove of Giant Sequoias

wildlife species have probably abandoned the habitat. The remaining species are not likely to further

change because they have adapted to the level of human disturbance. Natural hydrologic flow and

processes that are currently impacted by inadequate drainage culverts would continue to degrade

wildlife habitat in Mariposa Grove. Erosion and sedimentation form runoff would continue to

impact nearby habitat.

Impact Significance. Local, long­term, minor to moderate, adverse impacts.

Conclusion. No construction­related impacts would occur. Though there would be some continued

adverse effects on wildlife species, Operation­related impacts would include minor to moderate

human disturbance of wildlife.

Cumulative Impacts. The cumulative impacts on wildlife discussed in this section consider the past,

present, and reasonably foreseeable actions in the Yosemite region in combination with potential

effects of Alternative 1 (No Action). Regional impacts on wildlife began before the inception of

Yosemite National Park. Past impacts on wildlife include regional population growth, intensive

logging, fire suppression, rangeland clearing, grazing, mining, draining, damming, water diversions,

and the introduction of nonnative species. Purposeful efforts to eradicate predators were

widespread. For example, fur­bearing mammals were trapped by park rangers until 1925; mountain

lions were considered dangerous predators and controlled through the 1920s. Removal of predators

can have cascading effects through the food­chain. Natural wildfires with their overall beneficial

effects on wildlife habitat were suppressed routinely until 1972 (Wuerthner 1994).

Mammal species that once thrived in Yosemite, but are now extremely rare, are the fisher, wolverine

(possibly extinct), and Sierra Nevada red fox. Willow flycatchers no longer nest in Yosemite Valley

for a variety of complex reasons, including parasitism by brown­headed cowbirds, destruction of

riparian and meadow habitat, past cattle grazing, nest predation, and lack of a regionally sustainable

population. Population declines have been detected in numerous other bird species in the Sierra

Nevada, including the Yosemite area. Possible causes for these declines include grazing, logging, fire

suppression, development, recreational use, pesticides, habitat destruction on wintering grounds,

and large­scale climate changes.

Amphibians in Yosemite have suffered population declines similar to those seen in the rest of the

Sierra Nevada (Drost and Fellars 1996). Red­legged frogs were found in Yosemite in the past, but are

presumed extirpated from the park. Significant factors in their disappearance probably include

reduction in perennial ponds and wetlands, and predation by bullfrogs. At higher elevations, Sierra

Nevada yellow­legged frogs and Yosemite toads are still present in a number of areas but are severely

reduced in population and range. Foothill yellow­legged frogs may no longer be found in the park.

However, one population of foothill yellow­legged frog occurs adjacent to the park boundary on the

Tuolumne River, and there may be a small population in the park. Research continues to identify the

causes of Sierra Nevada­wide amphibian declines; possible causes include nonnative fish, pesticides,

habitat destruction, and diseases. Native fish in Yosemite were probably limited to rainbow trout and

the Sacramento sucker. Rainbow trout introduced through stocking have now hybridized with 

and/or displaced, the original strain. The combined impact of these past regional actions on wildlife

has been long­term, major, and adverse.

Present and future actions in the region would have beneficial and adverse effects (Appendix B).

Plans and actions with generalized beneficial impacts on special­status habitat include the Fire

Management Plan/Operational Fire Management Plan, Fuels reductions/forest rehabilitation projects

(US Forest Service), Invasive Plant Management Plan Update, Comprehensive Ecological Restoration

Actions, ecological restoration elements proposed in the Draft Merced and Tuolumne Wild and Scenic

Final Environmental Impact Statement 3­26 October 2013

Chapter 3: Affected Environment and

Environmental Consequences
     

               

   

         

             

             

                             

                         

                         

                   

                           

                     

                       

                     

                               

                           

                 

                         

                       

                       

                       

                   

                     

               

                             

                               

                     

                   

                         

                               

                           

                           

                             

             

           

                             

                         

                     

                     

                       

               

                             

                       

                       

                       

                         

                         

                               

Natural Resources: Wildlife

Restoration of the Mariposa Grove of Giant Sequoias

River Comprehensive Management Plans, Wawona Meadow Restoration, and the Wilderness

Stewardship Plan. Activities associated with the Fire Management Plan/Operational Fire Management

Plan and U.S. Forest Service fuels reduction projects would greatly reduce the threat of large highseverity catastrophic fires, and reduce the potential for vegetation type conversion and habitat loss.

Ecological restoration elements of the Draft Merced and Tuolumne Wild and Scenic River

Comprehensive Management Plans would result in long­term beneficial impacts on potential habitat

for wildlife. The Wawona Road Wildlife Crossings project and the under­road wildlife crossing at

the South Entrance Station Kiosks Replacement project would reduce the threat of future vehiclerelated fisher mortality in the south portion of Yosemite. Future efforts such as the Wilderness

Stewardship Plan could contribute watershed­scale protection to habitat for wildlife, depending on

the outcome of the final plan. These present and future actions would have a long­term moderate

beneficial effect on special­status species by increasing the quantity and quality of affected habitats.

There would be construction­related adverse impacts associated with the Yosemite Environmental

Education Center and new development proposed in the Draft Merced and Tuolumne Wild and

Scenic River Comprehensive Management Plans, due to the localized loss of upland habitat. There

would be localized clearing­related effects from the Scenic Vista Management Plan and the South 

Entrance Station Kiosks Replacement projects in upland habitats. Site­specific adverse effects on

wildlife could be short­term (during construction) and long­term (permanent displacement of

vegetation). NPS plans and projects include mitigation measures to protect wildlife, with emphasis

on protection during prime denning and nesting periods.

Changes in climate also pose a threat to wildlife, including American pika, yellow­legged frog and

bighorn sheep. These species, as well as a variety of amphibians, would be affected by warming

temperatures through transitions in vegetation communities, changes in snow pack and runoff, and

increasing competition from other species (including invasive species. Present and future

construction­ and climate­related impacts on wildlife would be long­term minor to moderate, and

adverse.

In summary, past impacts on wildlife in the have been adverse, long­term, and major. Some present

and foreseeable future actions would contribute to reversing the adverse impacts of past actions in

the region. Past, present, and future impacts, in conjunction with the local, long­term minor to

moderate adverse impacts of Alternative 1 (No Action) would result in a long­term moderate adverse

impact on wildlife in the Yosemite region.

Alternative 2: South Entrance Hub (Preferred Alternative)

Alternative 2 would remove the commercial tram operation and reduce the amount of lower Grove

area parking while expanding and relocating primary visitor parking to the South Entrance, making

the South Entrance the departure point for visitors accessing the Grove. Rehabilitation and

restoration actions, such as improvement of hydrologic flow, project­specific prescribed fire and

hazardous fuel reduction treatments, and soil decompaction would be components of this

alternative.

Construction­related Impacts. Construction­related activities would result in few adverse impacts

on wildlife and would be limited to the immediate construction zone. Removal of existing buildings

and infrastructure and construction of new facilities would generate noise and ground vibrations,

disturb habitat, and create other disturbances associated with human presence. Noise and human

activity within the construction zone may temporarily interrupt foraging, mating, and nesting

behavior, cause wildlife to temporarily avoid the area or interfere with animal movement patterns.

Disturbed nests in the immediate vicinity of construction activity would be susceptible to

abandonment. As a result, impacts on bird species and wildlife would be minor. Use of heavy

Final Environmental Impact Statement 3­27 October 2013

Chapter 3: Affected Environment and

Environmental Consequences
     

               

   

         

                           

             

                                   

                             

                             

                           

                               

                           

                           

                           

                         

                         

                     

                         

                                   

                             

                 

                 

                           

         

                   

                     

                         

                     

                       

                           

                       

                         

                       

                     

                             

                               

                               

                               

                               

                           

                                 

                     

               

           

                               

                     

                           

                           

                                   

Natural Resources: Wildlife

Restoration of the Mariposa Grove of Giant Sequoias

equipment creates the potential for wildlife injuries or death, specifically for small wildlife, such as

lizards and mammals that may become entrapped.

Removal of trees or snags could affect breeding bats or birds by removing nests or roosts. The impact

of tree removal would be minimized though site design and timing of removal; thus, impacts on

breeding bats or birds would be minimal. Removal of mature trees and snags would negatively

impact previously high­quality fisher habitat by removing dens. The impacts would be minimized by

timing the removal outside of the denning season (March 1 to June 30). These impacts would be

restricted to the development footprint and immediate vicinity and would be short­term, lasting only

as long as construction. Construction of infrastructure in the lower Grove area would occur in

previously disturbed wildlife habitat; as a result adverse impacts would be minor. Infrastructure and

facilities built at the South Entrance would be constructed in largely previously undeveloped wildlife

habitat. South Entrance would require clearing between 5.0 acres and 6.0 acres of non­giant sequoia

wildlife habitat. The net footprint after landscape restoration following South Entrance build­out

would equal 4.72 acres of non­giant sequoia wildlife habitat, including4.08 acres of impervious

surfaces. A new trail from South Entrance to the lower Grove area would impact a total of 0.66 acres,

which includes 0.42 acre along an existing road, 0.21 acre of new trail through non­giant sequoia

wildlife habitat, and 0.03 acre through giant sequoia wildlife habitat.

Impact Significance. Local, short­term, minor, adverse impacts would occur from construction

related noise and activity, and local, long­term, moderate, adverse impacts would occur from the

removal of trees and snags.

Restoration­related Impacts. The restoration of the Mariposa Grove of Giant Sequoias would

include restoring hydrology processes and wetland ecosystems to natural conditions, removing

infrastructure such as the road and parking lots, removing invasive species, and planting native

vegetation. Restoration activities have the potential to temporarily disturb populations of wildlife;

however, reduced vehicular traffic through the Mariposa Grove would have beneficial impacts on

the wildlife populations currently found in at the site because human disturbance, including sound

and noise pollution, would greatly decrease. Restoring native vegetation and hydrologic function

would help preserve the unique natural features and potentially increase biodiversity of wildlife

using the habitats surrounding the Mariposa Grove. Improvements to drainage culverts would

restore natural flow, and reduce sedimentation and erosion within wildlife habitat.

Beneficial impacts on wildlife habitat under Alternative 2 include (1) a 1.44 acre reduction of

impermeable surfaces within the lower Grove area due to removal of the lower Grove parking lot,

gift shop, and commercial tram staging area and operations, (2) restoration of 0.43 acre of giant

sequoia habitat from the removal of trails with Mariposa Grove, and (3) restoration of 2.11 acres of

giant sequoia habitat from the narrowing of road or conversion of roads to trails within Mariposa

Grove. Project­wide, the net change in development under Alternative 2 would result in the addition

of 0.75 acre in developed area which is comprised of 3.98 acres net reduction in of developed area

within the Grove plus 4.72 acres of new development at the South Entrance.

Impact Significance. Site specific, long­term, moderate, beneficial impacts on wildlife.

Operation­related Impacts. Disturbance from operations, recreations, and routine maintenance

affect wildlife using the habitats at the Mariposa Grove and in the surrounding areas. Types of

disturbance include noise, artificial light, human presence, automobile traffic, and other useassociated effects. Alternative 2 would remove and relocate public parking from the lower Grove

area to the park’s South Entrance and remove the commercial tram staging and operations resulting

in a change in traffic patterns and operations use. There would be a reduction in traffic in Mariposa

Final Environmental Impact Statement 3­28 October 2013

Chapter 3: Affected Environment and

Environmental Consequences
     

               

   

         

                           

                         

                               

                                   

                       

                         

                                 

                         

                             

                               

                             

                         

                         

                               

                              

                   

                     

                       

                     

                     

                             

                                 

                         

                         

                             

                       

                               

                               

                               

                               

                     

                 

                             

                           

                             

                             

                         

         

                               

                                 

                             

                               

                             

Natural Resources: Wildlife

Restoration of the Mariposa Grove of Giant Sequoias

Grove and a potential reduction in wildlife vehicle collisions. However, new facilities would increase

operational activity at the South Entrance and potential impacts on wildlife in that location.

Where roads in the Mariposa Grove would be narrowed and converted to primarily trail use, the

need to remove hazardous trees (dead snags or diseased trees that may fall on the road but provide

important wildlife habitat) would be reduced. Private vehicles with accessible placards (a vehicle

displaying a state­issued license plate, a state­issued accessible parking permit, or a temporary

Yosemite­issued parking permit) would still be able to drive to the Grizzly Giant, but traffic would be

reduced on the road due to the absence of the commercial tram tour.

Operational activities in the vicinity of the South Entrance would increase human disturbance in the

area. Wildlife in this area may be somewhat accustomed to human disturbance related to the existing

facilities. However, placing the main entrance facilities for the Mariposa Grove in this area would

increase activities that produce noise, which would disturb local wildlife, particularly breeding birds

and night­dwelling animals. These changes at the South Entrance would affect the local wildlife

populations by causing them to relocate to more suitable, less disturbed habitat or find new nesting

areas, which could affect reproductive success for a short period after new infrastructure is developed.

Impact Significance. Local, long­term, minor, adverse impacts in the Mariposa Grove where

operations­related impacts would be reduced from current levels. Local, long­term, moderate,

adverse impacts at the South Entrance where operational­related impacts are greater than current

levels.

Conclusion. Construction activities within the Mariposa Grove would result in some adverse

impacts on wildlife. Beneficial impacts from restoration­related activities would potentially restore

3.93 areas of wildlife habitat within the Mariposa Grove. After build­out, Alternative 2 would result

in a net 0.05 acre reduction of developed area, which is comprised of 3.98 acres net reduction of

developed area within the Grove plus 4.72 acres of new development at the South Entrance.

Construction of facilities at the South Entrance would require clearing between 5.0 acres and

6.0 acres of non­giant sequoia wildlife habitat. The net footprint after landscape restoration at the

South Entrance build­out would equal 4.72 acres of non­giant sequoia wildlife habitat, including

4.08 acres of impervious surfaces. A new trail from South Entrance to the lower Grove area would

impact 0.63 acre of non­giant sequoia wildlife habitat and 0.03 acre of giant sequoia wildlife habitat.

Operation­related adverse impacts on wildlife would be reduced in the Mariposa Grove as a result of

changes in traffic and use patterns, but would increase at the South Entrance from increases in traffic

and use patterns as a result of the new entrance facility.

Cumulative Impacts. The regional past, present, and reasonably foreseeable projects affecting

wildlife would be the same as those under Alternative 1 (No Action)—an overall long­term moderate

adverse impact on wildlife in the Yosemite region. These impacts in conjunction with the long­term

moderate beneficial impacts of Alternative 2 on wildlife in the Mariposa Grove, would contribute to

reversing the adverse impacts of past actions in the region, particularly within Yosemite. On a

regional scale, long­term moderate adverse impacts on wildlife in the Yosemite region would

continue.

Alternative 3: Grizzly Giant Hub

Alternative 3 would remove the commercial tram operation and build a new bypass road, two new

bridges, and a new larger parking lot near the Grizzly Giant. These new facilities would be located

outside of giant sequoia habitat but the new construction may affect Pacific fisher habitat. This

alternative would make the Grizzly Giant the primary departure point for visitors to the Grove. The

current South Entrance parking lot would remain as is and the lower Grove parking lot would be

Final Environmental Impact Statement 3­29 October 2013

Chapter 3: Affected Environment and

Environmental Consequences
     

               

   

         

                       

                       

                         

                 

                             

                         

                             

                             

                         

                             

                           

                         

                             

                           

            

                     

                         

                   

                             

                               

                                   

                         

                                   

                                 

         

               

                 

                         

                       

                         

                             

                                 

                             

                         

                                 

                               

                           

                       

                     

                   

                     

                         

                       

                             

Natural Resources: Wildlife

Restoration of the Mariposa Grove of Giant Sequoias

reconfigured as a smaller lot of ABAAS­compliant parking spaces. Rehabilitation and restoration

actions, such as improvement of hydrologic flow, project­specific prescribed fire and hazardous fuel

reduction treatments, and soil decompaction would be similar to those in Alternative 2.

Construction­related Impacts. Short­term minor adverse impacts and long­term adverse impact on

wildlife would primarily occur at the new Grizzly Giant bypass road and primary access facilities.

Construction of the bypass road would impact about 2.2 acres of wildlife habitat, which includes

0.33 acre through giant sequoia forest and 0.10 acre of raised crossings over wetlands. In addition,

the bypass road would disturb about 3.11 acres of prime denning habitat for the fisher.

Construction­related impacts on wildlife at the South Entrance would be less than those for

Alternative 2; because the South Entrance would not serve as the primary access node, fewer facility

improvements would be required in that location resulting in less ground disturbance and less

impact on wildlife and wildlife habitat. The Grizzly Giant Hub would require clearing approximately

5.61 acres of non­giant sequoia wildlife habitat. The net footprint after landscape restoration at the

Grizzly Giant Hub following build­out would equal 3.13 acres of non­giant sequoia wildlife habitat,

including 2.92 acres of impervious surfaces.

Impact Significance. Site specific, long­term, moderate, adverse impacts on wildlife within the

Grizzly Giant area and minor adverse impacts on wildlife at Mariposa Grove and South Entrance.

Restoration­related Impacts. Beneficial impacts on wildlife from Alternative 3 include (1) a

2.38­acre reduction of impermeable surfaces within the lower Grove area, (2) restoration of 0.58 acre

of giant sequoia habitat due to the removal of trails with Mariposa Grove, and (3) restoration of

2.79 acres of giant sequoia habitat due to the narrowing of road or conversion of roads to trails

within Mariposa Grove. Project­wide, the net change in development under Alternative 3 would

result in the addition of 0.50 acre in developed area which is comprised of 5.75 acre net reduction in

of developed area within the Grove plus 6.25 acres of new development at the Grizzly Giant arrival

area and new bypass road.

Impact Significance. Site specific, long­term, moderate, beneficial impacts on wildlife.

Operation­related Impacts. Under Alternative 3 disturbance to wildlife from operations,

recreation, and routine maintenance would occur primarily at Grizzly Giant bypass road and

primary access facilities. Types of disturbance include noise, artificial light, human presence,

automobile traffic, and other use­associated effects. Similar to Alternative 2, Alternative 3 would

remove and relocate public parking from the lower Grove area and remove the commercial tram

staging and operations resulting in a change in traffic patterns and operational use. There would be a

reduction in traffic in Mariposa Grove beyond Grizzly Giant and a potential reduction in wildlife

vehicle collisions in those areas. However, new facilities would increase operational activity and

potential wildlife impacts at the Grizzly Giant bypass road and access facility as the result of more

vehicles traveling to the bigger parking lot. Adverse impacts due to construction of new facilities at

the Grizzly Giant would occur in high quality wildlife habitat areas previously unaffected by roads,

vehicle transportation, and access facility operations. As a result, wildlife within areas previously

undisturbed by operation­related activities could experience moderate adverse impacts, but these

may be short­term if wildlife acclimates to new operation­related disturbance levels.

Impact Significance. Site specific, long­term, moderate, adverse impacts on wildlife within the

Grizzly Giant area and minor adverse impacts on wildlife at Mariposa Grove and South Entrance.

Conclusion. Adverse impacts from construction and operations on wildlife are expected to be

moderate at the Grizzly Giant bypass road and access facility and minor elsewhere within the

Final Environmental Impact Statement 3­30 October 2013

Chapter 3: Affected Environment and

Environmental Consequences
     

               

   

         

                         

                       

                             

                               

                               

                             

                 

                             

                           

                           

                             

               

                   

                             

                           

                           

                     

                       

              

               

                             

                       

                             

                                 

                               

                             

                 

                     

                   

                 

                             

                         

                         

                               

                               

                             

                                 

                       

                                   

                               

                             

                         

               

Natural Resources: Wildlife

Restoration of the Mariposa Grove of Giant Sequoias

Mariposa Grove and South Entrance. The moderate adverse impacts on wildlife would be associated

with the construction of the bypass road and increased traffic through prime fisher habitat, along

with the parking area and primary access facilities at the Grizzly Giant Hub. Project­wide, the net

change in development under Alternative 3 would result in the addition of 0.50 acre in developed

area which is comprised of 5.75 acre net reduction in of developed area within the Grove plus

6.25 acres of new development at the Grizzly Giant arrival area and new bypass road.

Cumulative Impacts. The regional past, present, and reasonably foreseeable projects affecting

wildlife would be the same as those under Alternative 1 (No Action)—an overall long­term moderate

adverse impact on wildlife in the Yosemite region. These impacts, in conjunction with the long­term

beneficial impacts of Alternative 3 within the Mariposa Grove, and the long­term moderate adverse

impacts near the Grizzly Giant hub and associated access road, would result in long­term moderate

adverse impacts on wildlife in the Yosemite region.

Alternative 4: South Entrance Hub with Modified Commercial Tram Service

Alternative 4 would maintain the commercial tram tours but with a limited route and hours of

operation while also relocating the majority of the parking to the South Entrance, making the South 

Entrance the primary departure point for visitors to the Grove. Numerous other rehabilitation and

restoration actions, such as improvement of hydrologic flow, project­specific prescribed fire and

hazardous fuel reduction treatments, soil decompaction, and improvement of visitor orientation and

interpretation, would be components of this alternative.

Construction­related Impacts. Adverse impacts resulting from relocation of infrastructure or

modification to existing infrastructure are expected to be similar to those described in Alternative 2.

Alternative 4 would construction the South Entrance similar to Alternative 2 and would

require clearing between 5.0 acres and 6.0 acres of non­giant sequoia wildlife habitat and would

result in a net build­out footprint of 4.72 acres including 4.08 acres of impervious surfaces. A new

trail from South Entrance to the lower Grove area would be constructed similar to Alternative 2 and

would impact 0.63 acre of non­giant sequoia wildlife habitat of which 0.42 acre follows an existing

road, and 0.03 acre of giant sequoia wildlife habitat.

Impact Significance. Site specific, long­term, minor, adverse impacts on wildlife within the

Mariposa Grove and moderate adverse impacts on wildlife at the South Entrance.

Restoration­related Impacts. Similar to Alternative 2 and Alternative 3, restoration­related impacts

would result in beneficial impacts on wildlife from the restoration of giant sequoia habitat and

hydrological function; and the resulting improvements to habitat quality and function from these

restoration actions. Specifically, beneficial impacts on wildlife and wildlife habitat from Alternative 4

include (1) a 1.59 acre reduction of impermeable surfaces within the lower Grove area due to

removal of the lower Grove parking lot, gift shop, and commercial tram staging area and operations,

(2) restoration of 0.02 acre of giant sequoia wildlife habitat from the removal of trails with Mariposa

Grove, and (3) restoration of 0.23 acres of giant sequoia wildlife habitat from the narrowing of road

or conversion of roads to trails within Mariposa Grove. Drainage and hydrologic improvements

would be similar to those in Alternative 2. Alternative 4 would restore 0.77 acre of wildlife habitat in

wetlands within the lower Grove area. Project­wide, Alternative 4 would result in a net addition of

developed areas of 2.88 acres, which is comprised of an estimated 1.84 acre net reduction in

developed area within the Grove plus 4.72 acres of new development at the South Entrance.

Impact Significance. Site specific, long­term, moderate, beneficial impacts on wildlife.

Final Environmental Impact Statement 3­31 October 2013

Chapter 3: Affected Environment and

Environmental Consequences
     

               

   

         

                   

                         

                               

                         

                             

                       

                     

                             

                 

                             

                       

                             

                           

                               

                                 

                               

                               

                           

                                 

                           

                 

                             

                           

                             

                             

                         

                         

                           

                         

                           

                           

                               

                           

                                 

                       

                     

                                     

                     

Natural Resources: Wildlife

Restoration of the Mariposa Grove of Giant Sequoias

Operation­related Impacts. Under Alternative 4, commercial tram service would continue to

operate on the existing road and cause operations­related impacts on wildlife. Commercial tram

operations would be reduced in the upper Grove area, but would continue unchanged in the lower

Grove area. The South Entrance would experience an increase in visitation and operational use

resulting in greater adverse impacts on wildlife similar to the impacts described for Alternative 2.

Impact Significance. Local, long­term, minor, adverse impacts in the upper Mariposa Grove where

operations­related impacts would be reduced from current levels. Local, long­term, moderate,

adverse impacts in the lower Grove area where operation levels would continue unchanged and at

the South Entrance where operational­related impacts are greater than current levels.

Conclusion. The existing road within the lower Grove area would not be narrowed to the upper

Grove area and existing adverse impacts on wildlife from traffic would continue. Construction

activities at the South Entrance would impact between 5.0 acres and 6.0 acres of non­giant sequoia

wildlife habitat, and at build­out the net footprint would total 4.72 acres. Operation­related adverse

impacts on wildlife would increase at the South Entrance due to increases in traffic and use patterns

as a result of the new transportation hub. The impacts from vehicular and commercial tram traffic on

the road between the lower and upper areas of the Grove would continue under Alternative 4.

Beneficial impacts on wildlife from Alternative 4 include a net restoration of about 1.84 acres within

the Grove as the result of relocating facilities to the South Entrance. Long­term beneficial impacts

would be similar to those in Alternative 2. Alternative 4 would result in less net reduction of

developed area than Alternative 2 because Alternative 4 includes less trail removal and road

narrowing.

Cumulative Impacts. The regional past, present, and reasonably foreseeable projects affecting

wildlife would be the same as those under Alternative 1 (No Action)—an overall long­term moderate

adverse impact on wildlife in the Yosemite region. These impacts, in conjunction with the long­term

moderate beneficial impacts of Alternative 4 on wildlife in the Mariposa Grove, would contribute to

reversing the adverse impacts of past actions in the region, particularly within Yosemite. On a

regional scale, long­term moderate adverse impacts on wildlife in the Yosemite region would

continue.

SPECIAL­STATUS SPECIES

The USFWS and the State of California Department of Fish and Wildlife (CDFW) classify

threatened, endangered, or rare species of plants and animals as those that have undergone serious

national, state or local declines and which may be threatened with extinction if not otherwise

protected. Federal and state regulations, including Section 7 of the 1973 Endangered Species Act

(USFWS 1998), CEQ regulations, as well as NPS Management Policies 2006 (NPS 2006), require

analysis of whether the proposed actions would cause impacts on any plant or animal species listed

or under consideration for listing as threatened or endangered. In addition, Yosemite National Park

recognizes state and local rare and sensitive species, and maintains its own list of “park special status

plant species.” These species have extremely limited distributions, represent relict populations from

past climatic or topographic conditions, have unique adaptations to local conditions (endemics),

occur at the extreme extent of their range in the park, or are listed by the California Native Plant

Society or the California Natural Diversity Database as rare or sensitive.

Final Environmental Impact Statement 3­32 October 2013

Chapter 3: Affected Environment and

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Natural Resources: Special­status Species

Restoration of the Mariposa Grove of Giant Sequoias

Affected Environment

Special­status Species Considered

For the purposes of this analysis, special­status wildlife species are limited to species listed by the

USFWS as an endangered, threatened, proposed, or candidate species; species identified by the

CDWF as an endangered, threatened, or candidate species; or CDWF species of special concern or

fully protected species, or California Bird Species of Special Concern. Special­states plant species in

this analysis include the categories used for wildlife; in addition, plant species identified by Yosemite

National Park as special­status species, species listed by the California Native Plant Society as

Rank 1A, 1B, or 2, and species on the U.S. Forest Service Threatened and Endangered or Watch Lists

are evaluated.

Each special­status species was evaluated to determine its potential to occur at either the Mariposa

Grove or the South Entrance and to be affected by the alternatives. This evaluation considered the

distribution and abundance of each species, habitat requirements of each species, habitat

characteristics of each site, and existing human disturbance at each site. Special­status wildlife

species with potential to occur or that occur at either project site are listed in table 3­1. Special­status

plant species are listed in table 3­2 and are described briefly in the following pages.

A total of 20 special­status wildlife species and 32 special­status plant species were considered in the

evaluation of the Mariposa Grove and South Entrance project sites (NPS 2013a and 2011e). As a result

of the preliminary assessment, including an analysis of distribution and abundance, habitat

requirements of each species, habitat characteristics of each project site, existing human disturbance

issues of each project site, and targeted 2010 surveys verifying occurrences (for plants), it was

determined that 12 of the 20 special­status wildlife species, and 10 of the 32 special­status plant

species warranted further consideration in the body of this Mariposa Grove FEIS based on

documented occurrence or suitable habitat available in the study area (table 3­1, table 3­2). The

remaining eight special­status wildlife species and 22 special­status plant species do not occur in the

project areas, have only anecdotal sightings, or suitable habitat is not present; therefore, there would

be no direct, indirect, or cumulative effects on these species from actions proposed in the alternatives.

These species are not evaluated further in this Mariposa Grove FEIS.

Table 3­1 – Special­status Wildlife Species

Species Name Status Habitat Preference

Mariposa Grove

Occurrence

South Entrance

Occurrence

Amphibians

California red­legged frog

(Rana draytonii)

FT Lakes, ponds, slow

streams, marshes, and

swamps, sea level to

1,525 m (5,000 ft.)

X X

Sierra Nevada yellow­legged frog

(Rana sierrae)

FC Lakes, ponds, meadow

streams, isolated deep

perennial pools, and

riverbanks

X X

Yosemite toad

(Bufo canorus)

FC Wet meadows ranging

from 1,950 to 3,444 m

(6,400 to 11,300 ft.)

X X

Final Environmental Impact Statement 3­33 October 2013

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Natural Resources: Special­status Species

Restoration of the Mariposa Grove of Giant Sequoias

Species Name Status Habitat Preference

Mariposa Grove

Occurrence

South Entrance

Occurrence

Birds

Bald eagle

(Haliaeetus leucocephalus)

CE, CFP Forested riparian areas

of lakes and rivers A X

California spotted owl

(Strix occidentalis occidentalis)

CSC, BSSC Late­stage oak and

ponderosa pine forests O P

Great gray owl CE Mixed conifer and

other conifer forest

types, wet meadow

A X

Golden eagle

(Aquila chrysaetos)

CFP Forest near open

terrain A X

Long­eared owl

(Asio otus)

CSC, BSSC Dense vegetation

adjacent to open

grassland or

shrubland, and open

forests

P X

Northern goshawk

(Accipiter gentilis)

CSC, BSSC Coniferous forests O P

Olive­sided flycatcher

(Contopus cooperi)

CSC, BSSC Coniferous forest O P

Peregrine falcon

(Falco peregrines)

CFP Sheer cliff habitat with

adjacent woodlands,

meadows, or marches

A X

Vaux’s swift

(Chaetura vauxi)

CSC, BSSC Coniferous or mixed

forest; forages in

forest openings,

especially above

streams

P X

Yellow warbler

(Dendroica petechia)

CSC, BSSC Wet, deciduous

thickets, especially in

willows

P X

Mammals

Pacific fisher

(Martes pennanti)

FC, CSC Mature coniferous

forests and deciduousriparian habitatsO P

Pallid bat

(Antrozous pallidus)

CSC Oak, ponderosa pine,

and giant sequoia

habitats

O P

Sierra Nevada mountain beaver

(Aplodontia rufa californica)

CSC Moist meadows and

montane riparian

habitat

A A

Spotted bat

(Euderma maculatum)

CSC Variety of habitats,

crevices O P

Townsend’s big­eared bat

(Corynorhinus townsendii)

CSC Near rocky areas; may

also occasionally

inhabit old buildings

P X

Western mastiff bat

(Eumops perotis californicus)

CSC Desert scrub and

chaparral to montane

coniferous forest

O P

Western red bat

(Lasiurus blossevillii)

CSC Strongly associated

with riparian and large

mature trees

O P

Notes: FC = Federal Candidate; CSC = California Species of Special Concern; BSSC = California Bird Species of Special

Concern; X = Does not occur, dismissed from further analysis; A = Anecdotal sighting habitat unsuitable, dismissed

from further analysis; O = Occurs based on documentation; P = Suitable habitat available in study area, but no

documentation

Final Environmental Impact Statement 3­34 October 2013

Chapter 3: Affected Environment and

Environmental Consequences
       

               

   

         

            

   

         

       

   

       

    

           

       

       

           

      

               

       

         

         

    

   

       

       

       

     

         

     

           

         

         

         

      

           

   

         

       

           

   

     

   

           

       

         

  

             

           

         

      

             

   

  

     

        

                                       

                                           

                             

     

                               

Natural Resources: Special­status Species

Restoration of the Mariposa Grove of Giant Sequoias

Table 3­2 – Special­status Plant Species

Scientific Name Common Name Location1 Status Habitat Preference

Arnica dealbata Mock leopardbane UG PSS Open montane forest, slopes and

dry meadows. Endemic to

California, from southernmost

Cascade Range to southern

Sierra Nevada.

Asarum lemmonii Lemmon’s wild

ginger

UG, LG, AR PSS Shaded drainage bottoms in

montane forest. Endemic to

California, known from Sierra

Nevada and one station in the

Southern Cascade ranges.

Arabis repanda var.

repanda

Repand rockcress UG PSS Openings in conifer forest, talus,

rock outcrops, dry meadows.

Known from the Sierra Nevada,

Transverse Ranges, and ranges in

western Nevada.

Carex sartwelliana Yosemite sedge UG, LG PSS Drainages in mid­elevation

forests and meadow borders.

Endemic to California, central

Sierra Nevada south to

Transverse and Peninsular

Ranges, northern end of species’

range in Yosemite.

Cinna bolanderi Bolander’s

woodreed

UG, LG PSS, CRPR 1B.2 Moist, partly shaded meadows

and stringers. Endemic to central

Sierra Nevada, with a significant

proportion of species range and

occurrences within Yosemite.

Collinsia childii Child’s blue­eyed

Mary

MR PSS Shaded slopes of open oak and

mixed coniferous woodlands.

Endemic to central and southern

Sierra Nevada, reaching the

northern extent of its range in

Mariposa County.

Hulsea brevifolia Short­leaved

alpinegold

UG PSS, FSS, SC,

CRPR 1B.2

Slopes with thin duff layer in

montane conifer forest. Endemic

to central and southern Sierra

Nevada.

Myrica hartwegii Sierra sweet­bay SE PSS, CRPR 4.3 Restricted to stream and river

banks at the average high water

line. Endemic to northern and

central Sierra Nevada.

Piperia colemanii Coleman’s piperia UG, LG, SE PSS, CRPR 4.3 Dry shade of mid­elevation

conifer forests.

Sequoiadendron

giganteum

Giant sequoia UG, LG PSS Well­watered drainages in

montane mixed conifer forest.

Notes: PSS = Park Service Special Status; FSS = U.S. Forest Service Sensitive; CRPR = California Native Plant Society Rare

Plant Rank (formerly CNPS list); UG = upper Grove; LG = lower Grove; AR = Access road south from Grizzly Giant to

Hwy 41; SE = South Entrance; MR = Road from South Entrance to Mariposa Grove

1 Location of 2010 Occurrences

Scientific and common names in this section match those found in Appendix C of NPS 2011a.

Final Environmental Impact Statement 3­35 October 2013

Chapter 3: Affected Environment and

Environmental Consequences
       

               

   

         

   

                               

                               

                           

                               

                             

    

                             

                               

                               

                       

                                 

                         

                         

                         

     

                           

                               

                             

                           

                         

                                 

                             

                       

    

           

           

             

             

                               

                             

                           

           

   

   

                               

                               

                         

                             

                             

                 

Natural Resources: Special­status Species

Restoration of the Mariposa Grove of Giant Sequoias

Critical Habitat

Section 7 of the Endangered Species Act requires federal agencies to ensure that any federal action

authorized, funded, or carried out is not likely to jeopardize the continued existence of listed species

or modify critical habitat. Critical habitat is defined as the specific geographic area, whether

occupied by listed species or not, that is determined to be essential for the conservation and

management of the listed species. Critical habitat for each listed species is formally described in the

Federal Register.

There are no federally listed species with potential to occur in the Mariposa Grove project area.

There are no designated critical habitat areas for federally listed species in the project area. The

Pacific fisher is a Candidate for listing under the federal Endangered Species Act. The NPS is

conducting informal consultation with the USFWS regarding the proposed actions described in this

Mariposa Grove FEIS, and mitigation actions to protect the fisher are enhanced as a result of this

consultation (see Appendix E, Mitigation Measures). Should the fisher be listed under the

Endangered Species Act prior to the completion of Mariposa Grove project implementation, the

NPS will enter into either informal or formal consultation or conference with the USFWS.

Special­Status Species Overview

A total of 12 special­status wildlife species, including six special­status bird species and six specialstatus mammal species, are known to occur or have suitable habitat available at the Mariposa Grove

or the South Entrance. Status and habitat preferences are identified in table 3­1. Of these, six specialstatus wildlife species have a strong association with the Mariposa Grove and South Entrance and

have been repeatedly detected during multiple surveys: the Pacific fisher, California spotted owl,

pallid bat, spotted bat, western mastiff bat, and the western red bat. A discussion of suitable habitat

or known populations of these special­status species at each of the project areas is provided below.

The special­status wildlife species observations discussed below are from the following four sources

(NPS 2013a):

• 2009­2011 Pacific fisher surveys (Cline 2013);

• Bat surveys (Pierson et al. 2006);

• NPS camera surveys conducted in 2011; and

• Owl survey data conducted over multiple years.

A total of 10 special­status plant species are known to occur at the Mariposa Grove or South 

Entrance. Status and habitat characteristics of these 10 species are identified in table 3­2. A

discussion of suitable habitat and locations of known populations of these special­status species at

each project area is provided below (NPS 2013a).

Mariposa Grove

Special­status Wildlife

California spotted owl. There is one California spotted owl active nest site and at least one territory

in the Mariposa Grove (NPS 2013a). The species has been detected in the Mariposa Grove since

1995 (1995, 2004­2006, 2007, and 2010­2011). Most recently surveys conducted by the U.S.

Geological Survey have resulted in 41 detections since 2004. Sierra mixed coniferous forest is the

most common plant community in the vicinity of the Mariposa Grove, and it provides suitable

roosting, nesting, and foraging habitat for the spotted owl.

Final Environmental Impact Statement 3­36 October 2013

Chapter 3: Affected Environment and

Environmental Consequences
       

               

   

         

                         

                           

                

                           

                           

                           

    

                       

                           

        

                                  

                         

                         

                             

                                 

                         

                             

                           

                               

                             

                             

                           

                           

                           

                         

                                 

                             

                           

                             

                                 

                                   

                                     

  

                       

                                   

                                     

                           

              

                   

                     

                     

                     

                           

Natural Resources: Special­status Species

Restoration of the Mariposa Grove of Giant Sequoias

Long­eared owl. Little is known about the status long­eared owl in Yosemite National Park (NPS

2013a). Although they have not been observed in the Mariposa Grove, the Grove appears to contain

suitable nesting and foraging habitat for long­eared owls.

Northern goshawk. There are five records of Northern goshawk in the Mariposa Grove and on

Mariposa Grove Road, dating from 1930, 1974, 1990, and 1992 (NPS 2013a). Key breeding

requirements, including suitable nesting and foraging habitat, and adequate prey, likely exist at the

Mariposa Grove.

Olive­sided flycatcher. There are two records of the olive­sided flycatcher in the Mariposa Grove

(1941, 1972) (NPS 2013a). The Mariposa Grove site appears to contain suitable coniferous forest

habitat for the species.

Pacific fisher. Yosemite National Park lies at the northern tip of the fisher’s current range in the

southern Sierra Nevada. The Pacific Fisher Status and Recovery 2009­2011 Final Report (Cline

2013) documented five to eight individual animals in and around Mariposa Grove and along

Wawona Road. Two fisher dens were documented in Yosemite National Park, and a third was

documented very near the park border. One of the dens was located 300 meters from the Mariposa

Grove Road. Additional NPS camera surveys conducted in 2011 confirm the presence of both 

female and male radio­collared fishers in an area that is proposed for future development under

some alternatives of the EIS. These studies suggest that fishers are distributed in low abundance

throughout a narrow corridor of habitat in the southern portion of the park that borders Sierra

National Forest; fishers do not currently occupy suitable habitat north of the Merced River and in

the western portion of the park (Cline 2013; 2013d). The Mariposa Grove is extremely important

contiguous habitat for the Pacific fisher. All alternatives in the Mariposa Grove occur in high quality

fisher habitat according to a fisher habitat suitability model by Spencer et al. (2008).

Pallid bat. Multiple occurrences of the pallid bat, including colonial roost sites in giant sequoias,

have been documented in the Mariposa Grove. The Mariposa Grove’s giant sequoias provide

important refugia for pallid bats. A 2006 report entitled Bat Use of the Giant Sequoia Groves in

Yosemite National Park documented the pallid bat’s use of giant sequoia basal fire scars in the

Mariposa Grove (Pierson et al. 2006). Three colonial roost sites in giant sequoias were documented

in 2000­2001. Additional colonial roost sites were reported in the lower Grove area, near the

commercial tram parking, and a pair of adjacent trees west of the Grizzly Giant. The largest number

of pallid bat detections in the Mariposa Grove has been along trails or in the relatively open seep

areas and rock outcrops, and the fewest have been along the creek and in the meadow (Pierson et al.

2006).

Spotted bat. Although rare in the Mariposa Grove, spotted bats have been detected acoustically in

the wet meadow area in the upper Grove area. This species is known to travel large distances from

its roost sites to forage and is thought to be an obligate cliff­dweller. It is likely that the Mariposa

Grove provides only suitable foraging habitat for the species; however, suitable cliff roosting habitat

may be found at adjacent Wawona Point.

Townsend’s big­eared bat. Although the Townsend’s big­eared bat has not been documented in

the Mariposa Grove, suitable habitat adjacent to rocky areas is present.

Vaux’s swift. In Yosemite National Park, Vaux’s swifts are probably widely distributed in oldgrowth forests where standing, hollow snags afford suitable nesting sites (NPS 2013a). Although the

Vaux’s swift has not been documented in the Mariposa Grove, suitable old­growth forest habitat is

present.

Final Environmental Impact Statement 3­37 October 2013

Chapter 3: Affected Environment and

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Natural Resources: Special­status Species

Restoration of the Mariposa Grove of Giant Sequoias

Western mastiff bat. There are few records of the western mastiff bat (2000, 2001) in the Mariposa

Grove, mostly associated with an open rock outcrop at Wawona Junction (a gap that may be a

flyway), and in the meadow in the upper Grove area (Pierson et al. 2006). The species has been

detected only acoustically and was relatively rare during the Pierson et al. 2006 bat surveys.

Western red bat. There are 25 records of western red bats in the Mariposa Grove (2000, 2001) that

were acoustically detected in an open rock setting at Rattlesnake Dome and on the road at Wawona

Junction (Pierson et al. 2006). The Wawona Junction is suspected as being a flyway for bats to enter

the grove (Pierson et al. 2006). Although other species, such as the pallid bat, have been documented

using the giant sequoias at the Mariposa Grove for roosting, this species has not been observed

roosting in these areas (Pierson et al. 2006).

Yellow warbler. The Mariposa Grove site contains a small amount of suitable riparian habitat for

the species ().

Special­status Plants

The presence of special status species including Sequoias are tied to the rich deep soils in the groves

which are partially attributable to glaciation of the grove site. The presence of a relatively large

number of special­status plant species in the Grove ties in part to the presence of metamorphic

bedrock and the consequent presence of metasedimentary soils and mineralized water. The soil and

water of this substrate have added nutrients, and soils have higher water retention capacities than

typical Sierra Nevada granitic bedrock environments.

Bolander’s woodreed. The park’s largest known population of Bolander’s woodreed is in the wet

meadow of the upper Grove area, below the Mariposa Grove Museum, with small patches also

present along small streams throughout the Mariposa Grove. Its preferred habitat is mostly shady,

moist sites along small streams or in stringer meadows at elevations ranging from 6,200 to 7,800 feet.

Child’s blue­eyed Mary. This species appears to be restricted to soils derived from

metasedimentary rocks, but is frequently encountered where the soil, slope, shade, elevation, and

moisture conditions are met. It occurs on steep, shady banks of creek drainages along the Mariposa

Grove Access Road and in the Wawona area.

Coleman’s piperia. Coleman’s piperia is often found in the dry shade of conifer forests. It is found

as widely scattered individuals throughout the area of the Mariposa Grove and South Entrance

Station. It is the most commonly encountered Piperia species in this area.

Giant sequoia. There are many stands of giant sequoia in the Mariposa Grove area. See the

Vegetation section of this chapter for detailed information about habitat characteristics.

Lemmon’s wild ginger. In the upper Grove area, this species is found in the wet meadow near the

Museum, and is frequent in all the small streams and moist drainages throughout the Grove (NPS

2011e).

Mock leopardbane. There is a single known occurrence of the mock leopardbane in the upper

Grove area that consists of several patches in the open forest along the trail from the upper Grove

loop road to Wawona Point (NPS 2011e). Mock leopardbane is fire­dependent and prefers open

ground in light shade of coniferous forests, where it grows in open mineral soil or shallow duff. Due

to its short stature (3 to 9 inches tall) it is easily shaded out by encroaching shrubs and herbaceous

vegetation.

Final Environmental Impact Statement 3­38 October 2013

Chapter 3: Affected Environment and

Environmental Consequences
       

               

   

         

                         

                               

                           

                                 

                             

  

                             

                       

                           

                                     

  

                             

                                 

                               

                       

   

   

                         

                           

     

                   

                          

                   

                         

                         

                   

                           

                               

                     

   

                       

                             

                           

                                       

                                 

             

                         

                       

                                     

     

Natural Resources: Special­status Species

Restoration of the Mariposa Grove of Giant Sequoias

Repand rockcress. Repand rockcress habitat is open, lightly shaded slopes with a thin duff layer,

such as occurs after low­intensity fires that remove downed fuel and thick duff. In the upper Grove

area, this species has appeared in large numbers on recent low­intensity prescribed burn slopes.

Although it was not observed in unburned forest outside of the upper Grove area in 2010, it may

appear on forest slopes outside the Mariposa Grove as these areas undergo prescribed burn (NPS

2011e).

Short­leaved alpinegold. The species has a single occurrence in the upper Grove area; this is a

single patch where the loop road intersects with the Wawona Point spur. This occurrence was

confirmed by additional surveys in 2003, 2004 and 2010 (NPS 2011e). Short­leaved alpinegold is firedependent and prefers light gaps in fir forest canopy where the duff layer is thin or mineral soil is

exposed.

Yosemite sedge. Yosemite sedge is common in moist seepages in the Mariposa Grove. It is seen

along the road between the upper and lower Grove areas (NPS 2011e). It prefers the thick organic

soils of streamsides and seepages in partial shade, although it persists in full sun after fire has

removed the overstory. Its population sizes appear to be boosted by fire.

South Entrance

Special­status Wildlife

California spotted owl. Although there are no records of the California spotted owl at the South 

Entrance, the South Entrance site contains suitable ponderosa pine and oak forest habitats for the

species (NPS 2013a).

Northern goshawk. Although there are no records of the northern goshawk at the South Entrance,

the South Entrance site contains suitable ponderosa pine and oak forest habitats for the species.

Olive­sided flycatcher. Although there are no records of the olive­sided flycatcher at the South 

Entrance, the South Entrance site contains suitable coniferous forest habitat for the species (NPS

2013a).

Pacific fisher: The South Entrance is located in high quality fisher habitat. Five to eight individual

animals were documented in and around Mariposa Grove, along Wawona Road, and the South 

Entrance area (Cline 2013). A fisher den was documented in Mariposa Grove and the South 

Entrance is located within the home range for that den site. In addition, radio­collared fishers have

been located at South Entrance during aerial telemetry flights (L. Cline, personal communication

September 2013).

Pallid bat. Although there are no records of the pallid bat at the South Entrance, the South Entrance

site contains Sierran mixed conifer forest habitat that is suitable for the species (NPS 2013a).

Spotted bat. Although there are no records of the spotted bat at the South Entrance, the species uses

a variety of habitats for foraging and is known to travel large distances from its roost sites to forage. It

is likely that the South Entrance provides only suitable foraging habitat for the species, as it does not

contain suitable cliff roosting habitat (NPS 2013a).

Western mastiff bat. Although there are no records of the western mastiff bat at the South Entrance,

the South Entrance site contains montane hardwood/conifer forest habitat that is suitable as a

foraging site for the species, but the area does not include cliff or outcrop habitat needed for a roost

site (NPS 2013a).

Final Environmental Impact Statement 3­39 October 2013

Chapter 3: Affected Environment and

Environmental Consequences
       

               

   

         

                               

                   

   

                           

                         

                               

                    

                             

           

                         

                                   

                               

                         

                           

                           

                                     

                                   

                         

                           

                             

                         

                     

                           

              

                         

                           

                           

                               

                             

                           

                           

                        

                         

                         

                                 

                               

         

Natural Resources: Special­status Species

Restoration of the Mariposa Grove of Giant Sequoias

Western red bat. Although there are no records of the western red bat at the South Entrance, the

South Entrance site contains suitable habitat for the species (NPS 2013a).

Special­status Plants

Child’s blue­eyed Mary. Child’s blue­eyed Mary appears to be restricted to soils derived from

metasedimentary rocks, but is frequently encountered where the soil, slope, shade, elevation and

moisture conditions are met. It occurs on steep, shady banks of creek drainages along the Mariposa

Grove Access Road, and in the Wawona area (NPS 2011e).

Coleman’s piperia. Coleman’s piperia is often found in the dry shade of conifer forests. It is found

in the vicinity of the South Entrance.

Sierra sweet­bay. The Sierra sweet­bay’s preferred habitat is rocky stream banks within the seasonal

flood zone, typically at the average high water line. It is found between 1,600 and 4,300 feet in mixed

conifer forest. It is known from two populations in Yosemite, one of which is continuous along Big

Creek from the South Entrance to its junction with the South Fork Merced River below Wawona.

Environmental Consequences

Impact Assessment Methodology

Determination of the significance of potential impacts on special­status species is based on the

locality, duration, type, and intensity of impact. The impact evaluation for special­status species was

based on the following: (1) the known or likely occurrence of a species or its preferred habitat in the

vicinity of the project area; (2) the direct physical loss or adverse modification of habitat; and (3) the

loss or degradation of habitat, such as could occur through avoidance or abandonment due to

construction or rehabilitation activity or noise, or the species’ sensitivity to human disturbance. For

plant species, this could occur due to loss of habitat features such as surface water flows.

Impacts were evaluated through determination of the location of the species or their habitat with 

respect to the proposed locations of various rehabilitation activities, such as culvert installation,

plant thinning, etc. Sensitivity of a species to impacts was assessed through consideration of rarity,

resilience, population size, and distribution throughout the park.

Data presented are based on field reconnaissance, literature review, the professional knowledge and

judgment of park staff, records of observations, published references, and studies of selected species.

Timely surveys specific to this planning effort would need to be conducted prior to implementation

to identify individuals or populations of special­status species within the project area at the time of

implementation.

Adverse impacts include those that would negatively affect the size, continuity, or integrity of habitat,

or result in unnatural changes in the abundance, diversity, or distribution of the species. Conversely,

impacts were classified as beneficial if they would positively affect the abundance, diversity, or

distribution of the species or the size, continuity, or integrity of habitat.

This evaluation also determines impacts on federal­ or state­listed special­status species based on

metrics specific to the Endangered Species Act. These impacts are defined as follows:

No Impact – The project (or action) is outside suitable habitat and there would be no disturbance or

other direct or indirect impacts on the species. The action would not affect special­status species or

designated critical habitat (USFWS 1998).

Final Environmental Impact Statement 3­40 October 2013

Chapter 3: Affected Environment and

Environmental Consequences
       

               

   

         

                                 

                                   

                       

                         

                     

                             

                             

               

                                   

                         

                                     

                     

     

       

                   

                         

                       

                       

                 

         

                 

                               

                             

                           

                         

                         

                       

                   

                           

                       

                           

                               

                                   

                           

                       

                         

                               

                         

                                 

                           

                       

                           

                           

Natural Resources: Special­status Species

Restoration of the Mariposa Grove of Giant Sequoias

May Affect, Not Likely to Adversely Affect – The project (or action) occurs in suitable habitat or

results in indirect impacts on the species, but the impact on the species is likely to be entirely

beneficial, discountable, or insignificant. The action may pose impacts on special­status species or

designated critical habitat but given circumstances or mitigation conditions, the impacts may be

discounted, insignificant, or completely beneficial. Insignificant impacts would not result in take.

Discountable impacts are those that are extremely unlikely to occur. Based on best judgment, a

person would not (1) be able to meaningfully measure, detect, or evaluate insignificant impacts or

(2) expect discountable impacts on occur (USFWS 1998).

May Affect, Likely to Adversely Affect – The project (or action) would have an adverse impact on a

special­status species as a result of direct, indirect, interrelated, or interdependent actions. An

adverse impact on a listed species may occur as a direct or indirect result of the proposed action or

its interrelated or interdependent actions and the impact is not: discountable, insignificant, or

beneficial (USFWS 1998).

Alternative 1: No Action

Under Alternative 1 current infrastructure, concessioner services and maintenance, and park

management would remain as is. No rehabilitation and restoration actions, such as improvement of

hydrologic flow and universal access, project­specific prescribed fire and hazardous fuel reduction

treatments, soil decompaction, and improvement of visitor orientation and interpretation, would be

implemented.

Construction­related Impacts. There would be no construction­related effects on the Mariposa

Grove under Alternative 1 (No Action).

Operation­related Impacts. Operational activities that disturb native vegetation have the potential

to disturb or injure special­status plants, specifically giant sequoia, in the vicinity of existing use areas

such as parking lots, roads, and trails. Operational activities are controlled to the extent possible and

avoid known sensitive areas; however, individuals may be trampled, and suitable habitat may be

affected, which could affect local populations and would be a noticeable, but minor, impact. Natural

hydrologic flow and processes that are currently impacted by inadequate drainage culverts would

continue to degrade special­status species habitat in the Mariposa Grove. Erosion and sedimentation

form runoff would continue to impact nearby special­status species habitat.

Continued operations would disturb special­status wildlife in the vicinity of the Mariposa Grove and

would continue to preclude species sensitive to human disturbance, such as the fisher. Operational

activities that affect suitable habitat, such as giant sequoia forests, would continue to affect species

that rely on the affected habitats for foraging, breeding, nesting and other uses by reducing the

quality of the habitat and possibly forcing the species to relocate or find other suitable habitat in the

region. Human disturbance from operational activities would continue to reduce the quality of the

surrounding habitats and disturb special­status species. Disturbance during the breeding and nesting

periods for special­status birds could result in effects on reproductive success, which could affect

local populations.

In particular, the California spotted owl, pallid bat, and fisher have the highest potential to be

affected by activities at the Mariposa Grove. Continued operations would disturb California spotted

owl which nest within 2 kilometers of the current parking lot and paved road, and forage in high use

areas (e.g., current parking lot). Operational and recreational activities can cause owls to abandon

disturbed habitat, and reduce reproductive success. Human disturbance and noise pollution from

operational activities and facilities would affect owls, which detect their prey primarily by sound, and

would thus affect foraging and breeding success of these species. Disturbance during the breeding

Final Environmental Impact Statement 3­41 October 2013

Chapter 3: Affected Environment and

Environmental Consequences
       

               

   

         

                       

                      

                           

                             

                                   

                                   

                               

                             

                         

                             

                       

                             

                               

                             

                                 

                           

                             

                               

                         

                       

  

                     

         

                           

                       

                 

                       

                     

            

                           

                   

                   

                           

                             

               

                     

                               

                 

                         

                         

                       

                       

                       

                       

                

Natural Resources: Special­status Species

Restoration of the Mariposa Grove of Giant Sequoias

and nesting periods for California spotted owls (breed from approximately February to September)

could result in impacts on reproductive success, which could affect local populations.

Pallid bats have reproductive roosts in the Mariposa Grove and could experience disruptive impacts

from operational activities similar to that of the California spotted owl. Pallid bats use giant sequoia

trees as their maternal roosts and colonial roost sites were recorded in the lower Grove area, near the

commercial tram parking, and a pair of adjacent trees in the middle grove, west of the Grizzly Giant.

Pierson et al. (2006) concluded that giant sequoia trees provided important refugia for pallid bats in

the Mariposa Grove. Pacific fishers have been detected in the Mariposa Grove, including in the

vicinity of high use areas, such as the South Entrance, Mariposa Grove Road, parking lot, trails

within the Grove, and the paved road leading up to Wawona Point (2013d). Wildlife vehicle

collisions have become a concern in Yosemite, with nine documented road­kill fishers (including

two lactating females) along the Wawona Road over the past two decades (Cline 2013). A tenth roadkill fisher has been documented on the nearby Glacier Point Road, and an additional three road­kill

fishers have been documented south of the park in Sierra National Forest along Highway 41 (Cline

2013). This stretch of road poses a significant threat for fishers and other wildlife because it bisects a

very narrow corridor of suitable habitat (Cline 2013). Existing surface water impacts that affect

hydrology and wetland ecosystems would have a negative effect on the condition of riparian habitat

that the Pacific fisher relies on for foraging, dispersal, and resting. Impacts on riparian areas could

further fragment corridor habitat and impede movement of individual fishers. Overall, there would

be long­term, minor operations­related adverse impacts on special­status plants and wildlife (NPS

2013a).

Restoration­related Impacts. There would be no restoration­related effects on the Mariposa Grove

under Alternative 1 (No Action).

Impact Significance. Alternative 1 (No Action) may affect, but is not likely to adversely affect statelisted special­status species. There are no known federal­listed species in the project area.

Conclusion. No construction­related or restoration­related impacts would occur under

Alternative 1 (No Action). Long­term, minor, adverse operation­related impacts would continue to

affect special­status plants. Long­term, minor adverse effects related to disturbance and habitat

degradation would continue for special­status wildlife.

Alternative 1 (No Action) may affect, but is not likely to adversely affect state­listed special­status

species. There are no federal­listed species in the project area.

Cumulative Impacts. The cumulative impacts on special­status species discussed in this section

consider the past, present, and reasonably foreseeable future actions in the Yosemite region in

conjunction with the potential effects of Alternative 1 (No Action). In the past 150 years, activities

associated with urbanization and regional population growth (e.g., building and dam construction,

utility installation, road and bridge building, intensive logging, stormwater discharge) contributed to

direct loss of habitat for special­status species in the Yosemite region. Impacts range from direct loss

of special­status species habitat (e.g., replaced with structures), alteration of natural environments

(e.g., fire suppression around structures, the introduction of night light), increased erosion and

sedimentation, and habitat fragmentation, to indirect habitat losses such as changes in water flows

that sustain plant communities. Purposeful efforts to eradicate predators were widespread. For

example, fur­bearing mammals were trapped by park rangers until 1925; mountain lions were

considered dangerous predators and controlled through the 1920s. The effect of reduced numbers

of predators can cascade throughout wildlife food chains. Other activities, particularly fire

suppression, changed the structure of existing native habitats.

Final Environmental Impact Statement 3­42 October 2013

Chapter 3: Affected Environment and

Environmental Consequences
       

               

   

         

                               

                           

                         

                             

                           

                       

                   

   

                               

                           

                       

                         

                           

                         

                           

                             

                       

                           

                             

                       

                   

           

                 

                         

             

                           

                             

                   

                 

                         

                         

                     

                       

                         

                         

                   

                         

                             

                     

                 

                           

                       

                               

                         

                             

                           

                   

                             

Natural Resources: Special­status Species

Restoration of the Mariposa Grove of Giant Sequoias

Mammal species that once thrived in Yosemite, but are now extremely rare, are the fisher, wolverine

(possibly extinct), and Sierra Nevada red fox. Willow flycatchers are likely extirpated from Yosemite

for a variety of complex reasons including parasitism by brown­headed cowbirds, destruction of

riparian and meadow habitat, past cattle grazing, nest predation, and lack of a regionally sustainable

population (Seigel 2007). Population declines have been detected in numerous other bird species in

the Sierra Nevada. Possible causes for these declines include grazing, logging, fire suppression,

development, recreational use, pesticides, habitat destruction on wintering grounds, and large­scale

climate changes.

Amphibians in Yosemite have suffered population declines similar to those seen in the rest of the

Sierra Nevada (Drost and Fellars 1996). Red­legged frogs are presumed extirpated from the park.

Significant factors in their disappearance probably include reduction in perennial ponds and

wetlands, and predation by bullfrogs. At higher elevations, Sierra Nevada yellow­legged frogs and

Yosemite toads are still present, but populations are severely reduced in population and range.

Foothill yellow­legged frogs may no longer be found in Yosemite. However, one population of

foothill yellow­legged frog occurs adjacent to the park boundary on the Tuolumne River, and there

may be a small population in the park. Research continues to identify the causes of Sierra Nevadawide amphibian declines; possible causes include nonnative fish, pesticides, habitat destruction, and

diseases. The impacts of these past regional actions on special­status species have been adverse.

Present and future actions in the region have beneficial and adverse effects on special­status species

(Appendix B). Plans and actions with beneficial impacts on special­status habitat include the

Wilderness Sierra Nevada Yellow­legged Frog Reintroduction and Trout Eradication Project, Fire

Management Plan/Operational Fire Management Plan, Fuels reductions/forest rehabilitation projects

(US Forest Service), Invasive Plant Management Plan Update, Comprehensive Ecological Restoration

Actions, ecological restoration elements proposed in the Draft Merced and Tuolumne Wild and Scenic

River Comprehensive Management Plans, Wawona Meadow Restoration, and the Wilderness

Stewardship Plan. The frog reintroduction and trout eradication project will increase the amount of

high quality aquatic habitat for the Sierra Nevada yellow­legged frog and improve the success rate of

Sierra Nevada yellow­legged frog reintroductions in high Sierra habitats. Activities associated with 

the Fire Management Plan/Operational Fire Management Plan and U.S. Forest Service fuels reduction

projects would greatly reduce the threat of large high­severity catastrophic fires, and reduce the

potential for vegetation type conversion and habitat loss. Ecological restoration elements of the

Draft Merced and Tuolumne Wild and Scenic River Comprehensive Management Plans would result in

long­term beneficial impacts on potential habitat for special­status species. The Wawona Road

Wildlife Crossings project and the under­road wildlife crossing at the South Entrance Station Kiosks

Replacement project would reduce the threat of future vehicle­related fisher mortality in the south 

portion of Yosemite. Future efforts such as the Wilderness Stewardship Plan could contribute

watershed­scale protection to habitat for special­status species, depending on the outcome of the

final plans. These present and future actions would have a long­term moderate beneficial effect on

special­status species by increasing the quantity and quality of affected habitats.

There would be construction­related adverse impacts associated with the Yosemite Environmental

Education Center and new development proposed in the Draft Merced and Tuolumne Wild and

Scenic River Comprehensive Management Plans, due to the localized loss of upland habitat. Localized

habitat for the valley elderberry longhorn beetle would be lost by actions proposed in the preferred

alternative of the Draft Merced Wild and Scenic River Comprehensive Management Plan. The NPS

would continue to work with the U.S. Fish and Wildlife Service on mitigation to reduce this potential

loss. There would be clearing­related effects on upland habitat related to the South Entrance Station

Kiosks Replacement project and the Scenic Vista Management Plan. Prime habitat for special­status

species would not be affected, or effects would be mitigated. The current required site­specific tree

Final Environmental Impact Statement 3­43 October 2013

Chapter 3: Affected Environment and

Environmental Consequences
       

               

   

         

                   

                     

                     

                     

                   

                           

                               

                   

                        

                             

                           

                         

                               

           

           

                   

                         

                           

                            

                   

                         

                       

                         

                         

                             

                         

                       

                   

                           

                         

    

                               

                       

                                 

                               

                           

                               

                                 

                         

                                 

                             

                             

                   

                         

                       

Natural Resources: Special­status Species

Restoration of the Mariposa Grove of Giant Sequoias

removal. Site­specific adverse effects on special­status species could be short­term (during

construction) and long­term (permanent displacement of vegetation). These plans and projects in

Yosemite include mitigation measures to protect special­status species, with emphasis on protection

during prime denning and nesting periods. Construction­related impacts on special­status species

would have a long­term moderate adverse impact on special­status species.

Changes in climate also pose a threat to several special­status species, including American pika,

yellow­legged frog and bighorn sheep. These species, as well as a variety of amphibians, would be

affected by warming temperatures through transitions in vegetation communities, changes in snow

pack and runoff, and increasing competition from other species (including invasive species).

In summary, past impacts on special­status species in the region have been adverse. Some present

and foreseeable future actions would contribute to reversing the adverse impacts of past actions in

the region. Present and future impacts, in conjunction with the minor adverse impacts on specialstatus species under Alternative 1 (No Action), would result in a long­term minor adverse impact on

special­status species in the Yosemite region.

Alternative 2: South Entrance Hub (Preferred Alternative)

Alternative 2 would implement comprehensive ecological restoration actions, including removing

the commercial tram operation, removing parking and restoring the lower Grove area to giant

sequoia habitat, improving hydrologic flows that sustain the giant sequoia, and converting roads to

trails. The South Entrance would be the primary departure point for visitors accessing the Grove.

Construction­related Impacts. Construction activities are not expected to result in direct impacts

on special­status plants. Impacts on special­status plant species would be similar to those described

in the “Vegetation” section. No special­status plants have been identified in the development

footprint, although several species, including giant sequoia, occur in the vicinity and could result in

indirect impacts similar to those identified in the “Vegetation” section. Construction pollutants in

runoff that travels offsite could potentially affect special­status plant species that may occur along or

near stream courses or associated wetland habitats, including the Lemmon’s wild ginger, Yosemite

sedge, Scribner woodreed, Sierra sweet­bay, and giant sequoia. Runoff of sediments and stormwater

pollutants could degrade downstream habitat conditions. With application of mitigation measures,

construction pollutants are not expected to result in a substantial reduction or degradation of

downstream wetland habitats due to application of mitigation measures to capture sediments and

stormwater pollutants.

In general, parking and development would be removed and reduced in the Mariposa Grove of giant

sequoias, and new construction would take place at the South Entrance where the transportation

hub and parking area would be relocated. The South Entrance area was heavily logged in the early

1900’s by the Madera Sugar Pine Company and forested areas consist of smaller diameter trees than

the giant sequoia grove, which has never been logged. The South Entrance is considered less valuable

habitat for special­status wildlife habitat due to the intensity of road traffic at the site when

compared to remote parts of the Grove, and because of the history of logging. Suitable habitat is

present for several species including the Northern goshawk, California spotted owl, pallid bat,

spotted bat, Western red bat, and Western mastiff bat. While suitable habitat is also present for the

fisher and animals have been documented in the vicinity, moving parking and the transportation hub

to the South Entrance would move this development farther away from the known fisher den site.

Construction activities would permanently disturb potential special­status habitat near the South 

Entrance. The net development footprint at the South Entrance would impact 4.72 acres of

previously logged non­giant sequoia habitat, including installation of 4.08 acres of impervious

Final Environmental Impact Statement 3­44 October 2013

Chapter 3: Affected Environment and

Environmental Consequences
       

               

   

         

                         

                 

                         

                             

                           

                             

                             

                         

                           

                   

                           

                         

                           

                         

                         

                                 

                             

                             

                             

                             

                           

                             

                          

                     

    

           

                           

        

                       

                       

                             

                               

                               

                               

                             

                           

                       

                         

                           

                         

           

                         

                           

                         

                         

Natural Resources: Special­status Species

Restoration of the Mariposa Grove of Giant Sequoias

surfaces. Vegetation clearing would cause individuals within the habitats to scatter or relocate.

Construction noise could disturb foraging behavior and compromise reproductive success.

Vegetation removal for construction operations could result in the removal of important habitat

elements such as snags, woody debris, canopy cover, and large trees. The expansion of the existing

facility at the South Entrance would create a larger barrier to wildlife movement through the local

area. However, the size of the expanded development footprint likely would not be sufficient to

substantially alter existing movement patterns of wildlife and access to unique or key habitat areas.

There would also be constructed­related impacts in the lower Grove area, though actions would

ultimately enhance habitat in the grove. Injuries and mortalities would be prevented by mitigation

measures that schedule construction activities with seasonal consideration of wildlife lifecycles to

minimize impacts during sensitive periods (i.e. after bird nesting and fisher denning seasons, when

bats are neither hibernating nor have young, etc.), establish construction buffer zones when fisher

are detected in the area, and ensure education and enforcement to limit construction worker

activities.

Construction actions proposed under Alternative 2 would decrease the size and continuity of

special­status habitat at the South Entrance. However, this would not affect the abundance, diversity,

or distribution of special­status species, as the size of the affected area is small in relation to the

amount of habitat available for special­status species in the area. In addition, the South Entrance area

is in close proximity to busy roads and the forest consists of previously logged second growth trees,

which do not provide the quality of habitat characteristics as the pristine forest in the Grove.

Relocation of the transportation hub out of the Mariposa Grove to the South Entrance likely would

have a beneficial impact on the fisher because traffic would be reduced between the South Entrance

and the Grove, which is prime denning habitat for the fisher. Overall, there would be a short­term,

minor adverse impact as a result of construction activities in the Mariposa Grove.

Impact Significance. Construction activities may affect, but are not likely to adversely affect statelisted special­status species.

Restoration­related Impacts. Long­term beneficial impacts would occur from restoration­related

activities. Beneficial impacts on special­status species would be similar to those described in the

“Vegetation” and “Wildlife” sections.

Ecological restoration of the Mariposa Grove would restore hydrology processes and wetland

ecosystems to natural conditions, removing infrastructure such as the road and parking lots,

removing invasive species, and planting native vegetation. There would be a 1.44 acre reduction of

impermeable surfaces within the lower Grove area due to removal of the lower Grove parking lot,

gift shop, and commercial tram staging area and operations, restoration of 0.43 acre of giant sequoia

habitat from the removal of trails with Mariposa Grove, and restoration of 2.11 acres of giant sequoia

habitat from the narrowing of road or conversion of roads to trails within Mariposa Grove.

Restoration of natural hydrologic flows would enhance habitat (currently over forty acres of surface

water runoff is diverted from natural flow patterns within the Mariposa Grove). Restoration

activities have the potential to disturb populations of the special­status plant species; however,

reduced use of the Mariposa Grove would have beneficial impacts on special­status plant species

populations. Mitigation measures already in place to protect resources and minimize impacts on

sensitive species and habitats would continue.

The restoration of the Mariposa Grove would include enhancing habitat for special­status wildlife,

such as the Pacific fisher, California spotted owl and pallid bat. Restoration activities have the

potential to temporarily disturb populations of special­status wildlife; however, reduced use of the

Mariposa Grove would have beneficial impacts on the populations of special­status species currently

Final Environmental Impact Statement 3­45 October 2013

Chapter 3: Affected Environment and

Environmental Consequences
       

               

   

         

                             

                       

                       

                         

                           

                           

                       

                 

                     

                       

         

                           

                               

                             

                             

                               

                               

                         

                               

                      

                   

                             

         

                     

                             

                           

          

                       

                         

                             

                         

                         

                             

                         

                         

                     

                               

                           

                         

                           

                                 

                     

Natural Resources: Special­status Species

Restoration of the Mariposa Grove of Giant Sequoias

found in at the site because human disturbance, including sound and noise pollution, would greatly

decrease. Restoring native vegetation and hydrologic function would help preserve the unique

natural features and potentially increase biodiversity of special­status wildlife using the habitats

surrounding the Mariposa Grove. Mitigation measures already in place to protect resources and

minimize impacts on sensitive species and habitats, such as reducing noise and light pollution, would

continue.

Beneficial impacts on special­status species from Alternative 2 include a 1.44 acre reduction of

impermeable surfaces within the Mariposa Grove which would provide for habitat restoration, soil

decompaction, and greater water infiltration. Improvements to roadway drainage culverts with 

diminished function or capacity, and implementation of sustainable stormwater strategies would

improve hydrologic connectivity, restore subsurface flows, and retain water within the Mariposa

Grove which would restore special­status species habitat.

Restoration actions proposed under Alternative 2 would increase the size and continuity of prime

special­status species habitat in the Mariposa Grove. The gift shop, the majority of the lower Grove

parking lot, and commercial tram staging area and operations would be removed from the Grove.

There would be a 1.44 acre reduction of impermeable surfaces within the lower Grove area,

restoration of 0.43 acre of giant sequoia habitat from the removal of trails within the Mariposa

Grove, and restoration of 2.11 acres of giant sequoia habitat from the narrowing of road or

conversion of roads to trails. Restoration of natural hydrologic flows would enhance habitat

(currently over forty acres of surface water runoff is diverted from natural flow patterns within the

Mariposa Grove). Restoration of 1.0 acre of wetland would be restored.

Impact Significance. Overall, restoration activities under Alternative 2 would have a long­term

major beneficial impact on special­status species. Alternative 2 may affect, but is not likely to

adversely affect state­listed special­status species.

Operation­related Impacts. Operational use would result in similar types of impacts as described

under Alternative 1 (No Action). Removal of road access and elimination of commercial tram service

would reduce operational activities levels in the Mariposa Grove, but new facilities would increase

operational activity at the South Entrance.

Operational activities could result in trampling or destruction of native vegetation, including specialstatus plants, and degradation of suitable habitat for special­status plants. Pedestrian traffic along

trails would continue sheet erosion of litter, duff, and topsoil. Removal of this protective covering

would continue to degrade special­status species habitat. Vandalism of giant sequoia could continue

in high­use areas. These impacts would be minimized with proper fencing, educational programs and

signage, and regular management and patrols of these areas. Additionally, removal of road access and

elimination of tram service from the Mariposa Grove would reduce human­related activities that

have the potential to disturb or injure giant sequoia compared to Alternative 1.

Reduced operations in the Mariposa Grove could decrease unregulated access into undisturbed

habitats adjacent to the abandoned roads. With a reduction in the number of roads in the Mariposa

Grove, the need to remove hazardous vegetation, such as large hollow trees, broken­top trees, snags,

and downed logs that support special­status species wildlife would be reduced. Reducing operations

in the Mariposa Grove and locating facilities to the South Entrance would move operations further

from existing nests for California spotted owl, roost for pallid bats, and the fisher den site; thus

reducing potential operations­related impacts on these species and protecting prime denning

habitat.

Final Environmental Impact Statement 3­46 October 2013

Chapter 3: Affected Environment and

Environmental Consequences
       

               

   

         

                                 

                           

                           

                               

                         

                       

                             

                                 

                           

                                 

                           

                 

                             

                           

                       

                       

                             

              

                       

                             

                         

                         

                               

                             

             

                       

                         

                           

                         

         

                         

                         

                               

                         

                             

                               

                               

                           

                                 

                                   

                        

                               

                                 

                       

                           

                                 

                             

Natural Resources: Special­status Species

Restoration of the Mariposa Grove of Giant Sequoias

Increased use of the South Entrance as a parking lot and for new visitor facilities could degrade

habitat conditions and reduce the quality of the habitats for some special­status wildlife. Suitable

habitat for several species is present including the Northern goshawk, California spotted owl, pallid

bat, spotted bat, Western red bat, Western mastiff bat, and Pacific fisher. Locating facilities at the

South Entrance would move operations farther from the known fisher den site. Vegetation and

habitat elements that could potentially support special­status species, such as mature conifer and

hardwood trees, large hollow trees, broken­top trees, snags, and downed logs, may be removed for

the new parking lot and buildings and could reduce use of the habitats at the South Entrance by

special­status birds and mammals. However, this area would be less valuable as special­status wildlife

habitat due to the intensity of road traffic compared to remote parts of the Grove. Relocation of

infrastructure and facilities and increasing the number of visitors under Alternative 2 would also

increase the extent and intensity of these human­caused operational disturbances. These

disturbances could reduce reproductive success of species breeding and nesting in the vicinity of the

redevelopment area and cause short­ or long­term abandonment of areas known or potentially used

by several special­status wildlife species. Disturbances on the landscape that restrict wildlife

movement and access to important habitats can affect dispersal, reproductive potential, and

distribution of species. The expansion of the existing facility at the South Entrance would create a

larger barrier to movement through the local area.

Removal of road access and elimination of commercial tram service would reduce operational

activities levels in the Mariposa Grove, but new facilities would increase operational activity at the

South Entrance. Overall, the impacts of operational activities would move from highly valued habitat

in the Mariposa Grove, to less highly valued habitat at the South Entrance. Operational changes

would result in a long­term, moderate beneficial impact in the Mariposa Grove, and a long­ term

minor adverse impact at the South Entrance area. These operational changes may affect, but are not

likely to adversely affect state­listed special­status species.

Impact Significance. Alternative 2 may affect, but is not likely to adversely affect state­listed specialstatus species. There are no federal­listed species associated with the Mariposa Grove area. Should

the Pacific fisher be proposed for federal listing under the Endangered Species Act during

implementation of the Mariposa Grove project, the NPS would consult with USFWS to ensure

adequate protection of the fisher.

Conclusion. There are no federal listed species in the Mariposa Grove project area, though a

number of other special­status species are present including the giant sequoia, California spotted

owl, pallid bat, and the Pacific fisher (a candidate for listing under the Endangered Species Act).

Construction actions proposed under Alternative 2 would decrease the size and continuity of

special­status habitat at the South Entrance. The size of the affected area would not affect the

abundance, diversity, or distribution of special­status species, as the size of the affected area is small

in relation to the amount of special­status habitat available for special­status species in the area. The

ongoing construction of wildlife crossings under Wawona Road (an action that is separate from the

actions evaluated in this EIS; see Appendix B) will mitigate the effects on wildlife corridors in this

area. In addition, the area affected at the South Entrance is in close proximity to busy roads and the

forest consists of second growth trees, which are not prime habitat for many species.

Relocation of the transportation hub out of the Mariposa Grove to the South Entrance is likely to

have a beneficial impact on the fisher, as visitor use and vehicles would be concentrated farther away

from prime fisher denning habitat. Restoration actions proposed under Alternative 2 would

substantially increase the size and continuity of prime special­status species habitat in the Mariposa

Grove. The majority of the lower Grove parking lot, gift shop, and commercial tram staging area and

operations would be removed from the Grove. There would be a 1.44 acre reduction of impermeable

Final Environmental Impact Statement 3­47 October 2013

Chapter 3: Affected Environment and

Environmental Consequences
       

               

   

         

                               

                               

                               

                             

                           

                           

                         

                               

        

                 

                           

                           

                   

                               

                           

               

         

                               

                                 

                             

                                 

                               

                 

                         

           

                   

                         

                               

                           

        

                       

                           

                               

                               

                                   

                               

                         

                   

                           

                     

                         

                           

                               

                                 

                             

Natural Resources: Special­status Species

Restoration of the Mariposa Grove of Giant Sequoias

surfaces within the lower Grove area, restoration of 0.43 acre of giant sequoia habitat from the

removal of trails within the Mariposa Grove, and restoration of 2.11 acres of giant sequoia habitat

from the narrowing of road or conversion of roads to trails. Restoration of natural hydrologic flows

would enhance habitat (currently over forty acres of surface water runoff is diverted from natural

flow patterns within the Mariposa Grove). Overall, Alternative 2 would substantially increase the size

and continuity of prime special­status species habitat in the Mariposa Grove, and reduce the

integrity of less­valued habitat at the South Entrance, resulting in a long­term moderate beneficial

impact on special­status species. Alternative 2 may affect, but is not likely to adversely affect federalor state­listed special­status species.

Cumulative Impacts. The regional past, present, and reasonably foreseeable projects affecting

special­status species would be the same as those under Alternative 1 (No Action)—an overall longterm moderate adverse impact on special­status species in the Yosemite region. These impacts, in

conjunction with the long­term moderate beneficial impacts of Alternative 2 on special­status

species in the Mariposa Grove, would contribute to reversing the adverse impacts of past actions in

the region, particularly within Yosemite. On a regional scale, long­term minor adverse impacts on

special­status species in the Yosemite region would continue.

Alternative 3: Grizzly Giant Hub

Alternative 3 would remove the commercial tram operation and construct a new bypass road to a

new, larger parking lot at the Grizzly Giant. The new road would require construction of two new

bridges. These new facilities would be located outside of giant sequoia habitat. The Grizzly Giant

would be the primary arrival point for visitors to the Grove. The current South Entrance parking lot

would remain as is, with 20 parking spaces, and the lower Grove parking lot would largely be

removed. Rehabilitation and restoration actions, such as improvement of hydrologic flow, projectspecific prescribed fire and hazardous fuel reduction treatments, and soil decompaction would be

similar to those in Alternative 2.

Construction­related Impacts. Impacts on special­status species would occur primarily at the new

Grizzly Giant by­pass road and primary access facilities, in prime fisher denning habitat.

Construction of the bypass road would impact about 2.2 acres of special­status species habitat in a

pristine forest (not previously logged), including 0.33 acre through giant sequoia habitat and 0.10 of

raised crossings over wetlands.

Construction equipment and activities would remove vegetation; create noise, lighting, and human

disturbances; and reduce the quality of the area for use by wildlife. Although construction activities

would be short­term in nature, the new road and parking area would be permanent. These facilities

and traffic could affect reproductive success of birds nesting in the vicinity, such as the spotted owl

or of bats roosting in trees. In addition, other special­status birds or mammals that are present in the

vicinity at the time of construction may be forced to relocate or could be injured by construction

equipment, particularly during grading and vegetation removal. The removal of large trees and snags

would affect many cavity­dependent species, such as owls, fisher, and bats.

In particular, construction activities and the permanent bypass road and Grizzly Giant parking area

would be moved to prime fisher denning habitat and/or known fisher occurrences. Construction

noise would disturb movement patterns, and foraging or breeding behavior of fishers. Vegetation

removal for construction operations could result in the removal of important habitat elements for

fisher, such as snags, woody debris, canopy cover, and nesting and roosting sites for owls and bats.

Fisher habitat within the proposed footprint of the Grizzly Giant parking area is an open mesa top

with mature pines and little understory; habitat that is less suitable for fishers, although a fisher was

Final Environmental Impact Statement 3­48 October 2013

Chapter 3: Affected Environment and

Environmental Consequences
       

               

   

         

                       

                              

                   

                             

                       

                             

            

               

                             

                                 

                         

                   

                               

                             

                                 

                                    

                   

                             

         

                 

                               

                             

                       

                     

                           

                             

                               

                     

                                 

                       

                             

                     

                            

                           

                       

                               

                         

                           

                           

                           

                         

                   

Natural Resources: Special­status Species

Restoration of the Mariposa Grove of Giant Sequoias

repeatedly documented in the proposed parking area during 2011 camera surveys (NPS 2013a).

Habitat within the footprint of the proposed new access road would traverse prime fisher habitat.

Impact Significance. Overall, there would be a long­term, major, adverse impact on special­status

species as a result of construction activities and permanent structures in the Mariposa Grove under

Alternative 3. Construction activities and permanent structures proposed under Alternative 3 may

affect, and are likely to adversely affect state­listed special­status species. There are no federal listed

species in the Mariposa Grove area.

Restoration­related Impacts. Beneficial impacts on special­status species from Alternative 3

include (1) restoration of 0.58 acre of giant sequoia habitat from the removal of trails with Mariposa

Grove, and (2) restoration of 2.79 acres of giant sequoia habitat from the narrowing of road or

conversion of roads to trails within Mariposa Grove. Restoration after the removal of impermeable

surfaces would provide for giant sequoia habitat restoration which would provide special­status

species habitat. Alternative 3 would restore 1.0 acre of wetlands habitat within the lower Grove area.

Project­wide, the net change in development under Alternative 3 would result in the addition of

0.50 acre in developed area which is comprised of 5.75 acre net reduction in of developed area within

the Grove plus 6.25 acres of new development at the Grizzly Giant arrival area and new bypass road.

Impact Significance. Restoration activities proposed under Alternative 3 would have a long­term,

major, beneficial impact on special­status species. Alternative 3 may affect, but is not likely to

adversely affect, state­listed special­status species.

Operation­related Impacts. Operation­related impacts on special­status species are expected to be

similar to those described in Alternative 2; however, the location of impacts would take place along

the Grizzly Giant by­pass road and primary access facilities. Adverse impacts would occur in areas

previously unaffected by roads, vehicle transportation and access facility operations. These impacts

could affect the local populations of special­status species previously undisturbed by operationrelated activities and could degrade suitable habitat, thus inhibiting species use of the area.

Operations at Grizzly Giant have potential to disturb special­status wildlife that rely on the habitats

in the area for nesting, breeding, foraging, roosting, and other uses. The types of impacts from

human disturbance and day­to­day activities would be similar to those described under

Alternative 2, and impacts on species would be similar because the same species occur in the vicinity

of Grizzly Giant. Impacts on special­status species in general would include general disturbance

from noise and lighting, habitat loss, degradation or reduced quality of the habitat at and

surrounding Grizzly Giant, potential injury or mortality to wildlife, and reduced reproductive

success for birds and bats that have been using the area in the past.

Disturbances on the landscape that restrict wildlife movement and access to important habitats can

affect dispersal, reproductive potential, and distribution of species. Establishment of the Grizzly

Giant facilities would create a barrier to movement through the local area. However, the size of the

development would likely not be sufficient to substantially alter existing movement patterns of

wildlife and access to unique or key habitat areas. Riparian corridors provide important dispersal

habitat or landscape linkages for Pacific fishers and provide important rest site elements, such as

broken tops, snags, and coarse woody debris (Heinemeyer and Jones 1994; Seglund 1995). However,

primary movement corridors following the drainages south of the Grizzly Giant are not anticipated

to be directly affected by the construction of new facilities.

Final Environmental Impact Statement 3­49 October 2013

Chapter 3: Affected Environment and

Environmental Consequences
       

               

   

         

                 

                 

       

           

               

                 

             

               

             

               

       

           

             

       

           

             

                 

          

       

               

                             

                             

                         

                         

                               

                         

                         

         

                             

                                 

                                 

                         

                           

                             

          

                 

                           

                           

                           

                         

                         

       

                   

                           

                             

                 

             

   

Natural Resources: Special­status Species

Restoration of the Mariposa Grove of Giant Sequoias

Of particular concern at the Grizzly Giant bypass road

and facilities is the Pacific fisher (figure 3­10), which has

documented occurrences near these features.

Operations would introduce human disturbance, noise

and light pollution at Grizzly Giant which would affect

breeding and resting behavior of fisher using the site.

More importantly, there is an increased potential for

fisher road­kills with more than double the increase in

private vehicle traffic. Increased vehicular traffic near

occupied fisher habitat would have the potential to

increase mortality through collisions with vehicles. A

new by­pass road would fragment contiguous high 

quality fisher habitat in the Mariposa Grove.

Impact Significance. Overall, there would be longterm, moderate, adverse operational impacts on specialstatus species under Alternative 3. Operations activities

under Alternative 3 may affect, and are likely to

adversely affect state­listed special­status species.

Conclusion. While ecological restoration activities

under Alternative 3 would have a major beneficial

impact on special­status species, there would be major adverse impacts on special­status habitat as a

result of construction of a new road in prime fisher denning habitat, and moderate adverse

operational impacts. Construction activities, and the permanent bypass road and new parking lot

proposed under Alternative 3 may affect, and are likely to adversely affect state­listed special­status

species. There are no federal listed species in the Mariposa Grove area. Should the fisher (current

Candidate Species) be proposed for federal listing under the Endangered Species Act during

implementation of the Mariposa Grove project, the NPS would consult with USFWS to ensure

adequate protection of the fisher.

Project­wide, the net change in development under Alternative 3 would result in the addition of

0.50 acre in developed area (comprised of 5.75 acre net reduction in developed area within the Grove

and 6.25 acres of new development at the Grizzly Giant arrival area and new bypass road). In

accordance with the Endangered Species Act, the park will consult with the U.S. Fish and Wildlife

Service further regarding the potential for adverse effects resulting from the implementation of the

proposed actions, and additional mitigation may be identified. Alternative 3 may affect, and is likely

to adversely affect special­status species.

Cumulative Impacts. The regional past, present, and reasonably foreseeable projects affecting

special­status species would be the same as those under Alternative 1 (No Action)—an overall longterm moderate adverse impact on special­status species in the Yosemite region. These impacts, in

conjunction with the long­term beneficial impacts of Alternative 3 in the Mariposa Grove, and the

long­term moderate adverse impacts associated with construction of the Grizzly Giant hub and

associated access road would result in long­term moderate adverse impacts on special­status species

in the Yosemite region.

Alternative 4: South Entrance Hub with Modified Commercial Tram Service

Under Alternative 4, the South Entrance would be the primary departure point for visitors accessing

the Grove. This alternative would maintain the commercial tram with a limited route and hours of

operation. Comprehensive ecological restoration actions would take place; including removing

Figure 3­10 – Pacific Fisher

Source: University of California Berkeley and National

Park Service

Final Environmental Impact Statement 3­50 October 2013

Chapter 3: Affected Environment and

Environmental Consequences
       

               

   

         

                             

                         

                   

            

                   

                         

                               

                     

                         

                           

                         

        

                               

                       

                               

                           

                           

                

                   

                         

                       

                         

                 

                         

                             

                           

                       

                           

                 

                             

                     

                           

                         

                         

                                 

                           

                               

                                 

                                 

                             

                             

                             

                      

                           

                             

          

Natural Resources: Special­status Species

Restoration of the Mariposa Grove of Giant Sequoias

parking and restoring the lower Grove area to giant sequoia habitat, improving hydrologic flows that

sustain the giant sequoia, and converting roads to trails. Project­specific prescribed fire and

hazardous fuel reduction treatments and improvement of visitor orientation and interpretation,

would be components of this alternative.

Construction­related Impacts. Construction activities are not expected to result in direct impacts

on special­status plants. Impacts on special­status plant species would be similar to those described

in the “Vegetation” section for Alternatives 2 and 4. No special­status plants have been identified in

the development footprint, although several species, including giant sequoia, occur in the vicinity

and could result in indirect impacts from construction pollutants in runoff. With application of

mitigation measures, construction pollutants are not expected to result in a substantial reduction or

degradation of downstream wetland habitats due to application of mitigation measures to capture

sediments and stormwater pollutants.

In general, parking and development would be removed and reduced in the Mariposa Grove of giant

sequoias, and new construction would take place at the South Entrance where the transportation

hub and parking area would be relocated. Suitable habitat is present for several species including the

Northern goshawk, California spotted owl, pallid bat, spotted bat, Western red bat, Western mastiff

bat, and fisher. Moving parking and the transportation hub to the South Entrance would move

development farther away from the known fisher den site.

Construction activities would permanently disturb potential special­status habitat near the South 

Entrance. The net development footprint at the South Entrance would impact 4.72 acres of

previously logged non­giant sequoia habitat, including installation of 4.08 acres of impervious

surfaces. Vegetation clearing would cause individuals within the habitats to scatter or relocate.

Construction noise could disturb foraging behavior and compromise reproductive success.

Vegetation removal for construction operations could result in the removal of important habitat

elements such as snags, woody debris, canopy cover, and large trees. The expansion of the existing

facility at the South Entrance would create a larger barrier to wildlife movement through the local

area. There would also be constructed­related impacts in the lower Grove area, though actions

would ultimately enhance habitat in the grove. Injuries and mortalities would be prevented by

mitigation measures that schedule construction activities with seasonal consideration of wildlife

lifecycles to minimize impacts during sensitive periods (i.e. after bird nesting seasons, when bats are

neither hibernating nor have young, etc.), establish construction buffer zones when fisher are

detected in the area, and ensure education and enforcement to limit construction worker activities.

Construction actions proposed under Alternative 4 would decrease the size and continuity of

special­status habitat at the South Entrance. However, this would not affect the abundance, diversity,

or distribution of special­status species, as the size of the affected area is small in relation to the

amount of habitat available for special­status species in the area. The ongoing construction of

wildlife crossings under Wawona Road (an action that is separate from the actions evaluated in this

EIS; see Appendix B) will mitigate the effects on wildlife corridors in this area. In addition, the South 

Entrance area is in close proximity to busy roads and the forest consists of previously logged second

growth trees, which do not provide the quality of habitat characteristics as the pristine forest in the

Grove. Relocation of the transportation hub out of the Mariposa Grove to the South Entrance likely

would have a beneficial impact on the fisher because traffic would be reduced between the South 

Entrance and the Grove, which is prime denning habitat for the fisher.

Impact Significance. Overall, there would be a short­term, minor, adverse impact as a result of

construction activities in the Mariposa Grove. Construction activities may affect, but are not likely to

adversely affect state­listed special­status species.

Final Environmental Impact Statement 3­51 October 2013

Chapter 3: Affected Environment and

Environmental Consequences
       

               

   

         

                 

                           

                         

            

                   

                             

                         

         

             

                                 

                     

                             

                           

         

                         

                                 

                           

                             

                           

                           

                           

                         

     

                           

                       

                           

                               

                                   

                           

                       

                         

                               

                         

                                 

                           

                       

                           

                           

                       

                      

                           

                             

                                   

                                   

Natural Resources: Special­status Species

Restoration of the Mariposa Grove of Giant Sequoias

Restoration­related Impacts. Similar to effects described under Alternatives 2 and 3, restorationrelated impacts would result in beneficial impacts on special­status species from the restoration of

giant sequoia habitat and hydrological function; and the resulting improvements to habitat quality

and function from these restoration actions.

Impact Significance. Alternative 4 is expected to have site­specific, long­term, moderate, beneficial

impacts on special­status species within the Mariposa Grove. Alternative 4 may affect, but is not

likely to adversely affect state­listed special­status species. There are no known federal­listed species

in the Mariposa Grove area.

Operation­related Impacts. Commercial tram traffic would run through special­status wildlife

habitat on a daily basis. The Grove Road would continue to need maintenance to support tram tours.

This would involve paving, road stabilization, and other maintenance. Commercial tram operations

would be reduced in the upper Grove area. The South Entrance would experience an increase in

visitation and operational use resulting in greater adverse impacts on special­status species, similar to

that described in Alternative 2.

Operational activities would have the potential to disturb or injure special­status plants, specifically

giant sequoia, in the vicinity of existing use areas such as parking lots, roads, and trails. The NPS

would limit operational impacts to the extent possible and avoid known sensitive areas; however,

individual plants may be trampled, and suitable habitat may be affected, which could affect local

populations and would be a noticeable minor, impact. Natural hydrologic flow and processes that

are currently impacted by inadequate drainage culverts would be improved to the extent possible,

but special­status species habitat in the Mariposa Grove would continue to be affected by the

presence of roads. Erosion and sedimentation form runoff would continue to impact nearby specialstatus species habitat.

Continued operations would disturb special­status wildlife in the vicinity of the Mariposa Grove and

would continue to preclude species sensitive to human disturbance, such as the fisher. Operational

activities that affect suitable habitat, such as giant sequoia forests, would continue to affect species

that rely on the affected habitats for foraging, breeding, nesting and other uses by reducing the

quality of the habitat and possibly forcing the species to relocate or find other suitable habitat in the

region. Human disturbance from operational activities would continue to reduce the quality of the

surrounding habitats and disturb special­status species. Disturbance during the breeding and nesting

periods for special­status birds could result in effects on reproductive success, which could affect

local populations.

In particular, the California spotted owl, pallid bat, and fisher have the highest potential to be

affected by activities at the Mariposa Grove. Continued operations would disturb California spotted

owl which nest within 2 kilometers of the current parking lot and paved road, and forage in high use

areas (e.g., current parking lot). Operational and recreational activities can cause owls to abandon

disturbed habitat, and reduce reproductive success. Human disturbance and noise pollution from

operational activities and facilities would affect owls, which detect their prey primarily by sound, and

would thus affect foraging and breeding success of these species. Disturbance during the breeding

and nesting periods for California spotted owls (breed from approximately February to September)

could result in impacts on reproductive success, which could affect local populations.

Pallid bats have reproductive roosts in the Mariposa Grove and could experience disruptive impacts

from operational activities similar to that of the California spotted owl. Pallid bats use giant sequoia

trees as their maternal roosts and colonial roost sites were recorded in the lower Grove area, near the

commercial tram parking, and a pair of adjacent trees in the middle grove, west of the Grizzly Giant.

Final Environmental Impact Statement 3­52 October 2013

Chapter 3: Affected Environment and

Environmental Consequences
       

               

   

         

                               

      

                               

                           

                             

                       

                           

                           

                               

                                 

                         

                                   

                         

                       

                

                   

                             

                         

                             

                         

                           

                             

                       

                               

                       

                         

                                 

                               

                            

                 

                           

                           

                   

                               

                           

               

                           

                             

                                   

                           

                       

                   

Natural Resources: Special­status Species

Restoration of the Mariposa Grove of Giant Sequoias

Pierson et al. (2006) concluded that giant sequoia trees provided important refugia for pallid bats in

the Mariposa Grove.

Pacific fishers have been detected in the Mariposa Grove, including in the vicinity of high use areas,

such as the South Entrance, Mariposa Grove Road, parking lot, trails within the Grove, and the

paved road leading up to Wawona Point (2013d). Wildlife vehicle collisions have become a concern

in Yosemite, with nine documented road­kill fishers (including two lactating females) along the

Wawona Road over the past two decades (Cline 2013). A tenth road­kill fisher has been documented

on the nearby Glacier Point Road, and an additional three road­kill fishers have been documented

south of the park in Sierra National Forest along Highway 41 (Cline 2013). This stretch of road poses

a significant threat for fishers and other wildlife because it bisects a very narrow corridor of suitable

habitat (Cline 2013). Existing surface water impacts that affect hydrology and wetland ecosystems

would have a negative effect on the condition of riparian habitat that the Pacific fisher relies on for

foraging, dispersal, and resting. Impacts on riparian areas could further fragment corridor habitat

and impede movement of individual fishers. Overall, there would be long­term, minor operationsrelated adverse impacts on special­status plants and wildlife.

Impact Significance. Overall, there would be long­term, minor, operations­related adverse impacts

on special­status plants and wildlife as the result of operations under Alternative 4. Alternative 4 may

affect, but is not likely to adversely affect special­status species. In accordance with the Endangered

Species Act, the park will consult with the USFWS further regarding the potential for adverse effects

resulting from the implementation of the proposed actions, and additional mitigation may be

identified.

Conclusion. Under Alternative 4, there would be short­term, minor adverse impact as a result of

construction activities in the Mariposa Grove. While operations would be limited in the upper Grove

area, long­term, minor operations­related adverse impacts on special­status plants and wildlife they

would continue in the lower Grove area. There would be a long­term moderate beneficial impacts on

special­status species from restoration actions. Actions include 1.84 acres of potential habitat

restoration within Mariposa Grove. Project­wide, the net change in development under Alternative 4

would result in the addition of 2.88 acres in developed area which is comprised of 1.84 acre net

reduction in of developed area within the Grove plus 4.72 acres of new development at the South 

Entrance. Alternative 4 may affect, but is not likely to adversely affect, special­status species.

Cumulative Impacts. The regional past, present, and reasonably foreseeable projects affecting

special­status species would be the same as those under Alternative 1 (No Action)—an overall longterm moderate adverse impact on special­status species in the Yosemite region. These impacts in

conjunction with the long­term moderate beneficial impacts of Alternative 4 on special­status

species in the Mariposa Grove, would contribute to reversing the adverse impacts of past actions in

the region, particularly within Yosemite. On a regional scale, long­term minor adverse impacts on

special­status species in the Yosemite region would continue.

WETLANDS

Affected Environment

Wetlands are transitional areas between terrestrial and aquatic ecosystems, where water is usually at

or near the surface or the land is covered by shallow waters. Wetlands have many distinguishing

features, the most notable of which are the presence of standing water or soil saturation (for at least a

portion of the growing season) and plants adapted to or tolerant of saturated soils (Mitsch and

Gosselink 1993).Wetlands are considered highly valued resources because they perform a variety of

hydrological and ecological functions vital to ecosystem integrity (NPS 2011f).

Final Environmental Impact Statement 3­53 October 2013

Chapter 3: Affected Environment and

Environmental Consequences
     

               

   

         

                                 

                             

                       

                             

                   

                             

             

                             

                         

                       

                           

                     

                       

                             

                               

                           

                             

       

                           

                         

                       

                               

                         

                       

                       

                                 

                       

                             

                             

                           

                       

     

                                 

                                 

                         

                   

             

     

                         

                             

                               

                       

                           

                               

                           

                           

Natural Resources: Wetlands

Restoration of the Mariposa Grove of Giant Sequoias

Wetlands and other waters of the United States are regulated under Section 404 of the Clean Water

Act, Executive Order 11990: Protection of Wetlands (42 FR 26961), and NPS Director’s Order #77­1:

Wetland Protection. Wetland boundaries at the Mariposa Grove and the South Entrance were

mapped following the U.S. Army Corps of Engineers (2008) Regional Supplement to the Corps of

Engineers Wetland Delineation Manual: Western Mountains, Valleys, and Coast Region. Wetland

habitats were classified using the USFWS guidance (Cowardin et al. 1979), which is the basis for

wetland classification and protection used by the NPS.

The USFWS system classifies wetlands based on type of vegetative cover and life form, flooding

regime, and substrate material (Cowardin et al. 1979). Jurisdictional wetlands are delineated and

classified in accordance with Section 404 of the Clean Water Act. USFWS­defined wetlands include

jurisdictional wetlands, but may also include certain nonvegetated sites, if they meet specific criteria.

Wetland investigations were performed at the Mariposa Grove and South Entrance during August,

September, and October of 2011. Landscape position, soils, vegetation, and hydrology were

evaluated in detail at sample points scattered across the project area, and wetland boundaries were

delineated (NPS 2011f). A total of 102.7 acres of wetland were delineated in the Mariposa Grove;

these were a mix of palustrine forested, palustrine scrub shrub, palustrine emergent, and riverine

wetlands (NPS 2011f). A total of 1.4 acres of palustrine wetland were delineated in the South 

Entrance area (NPS 2011f).

Prior to construction of the road through the Mariposa Grove and the South Entrance areas, these

wetlands formed what had been a continuous dendritic network. Currently, the Mariposa Grove

Road fragments the former contiguous wetland, altering wetland hydrology and other functions.

Incense cedar, white fir, giant sequoia and other trees rooted in wetlands provide over 30 percent

cover throughout most of the area’s wetlands, primarily in wide valleys where topography flattens

out. Many wetlands have a thick understory of shrubs, such as Western azalea (Rhododendron

occidentalis) and red­twig dogwood (Cornus sericea), forbs, and emergent vegetation. In these areas,

soils are dark brown sandy loams along wetland edges, grading into deep black silt loams toward the

wetland centers. Most wetland areas are saturated to the ground surface. Currently, infrastructure

such as roads, parking areas, trails, and visitor facilities are within some of the identified wetland

areas, and may be negatively affecting wetland and stream hydrology and function. In addition, the

leaking water supply pipeline from Biledo Spring in the Sierra National Forest to the South Entrance

loses an estimated 39,000 gallons of water per day within the Grove.

Mariposa Grove Setting

The Mariposa Grove and its wetlands are not only unique because of the presence of giant sequoias

but also because of the great diversity of habitats, plants, and wildlife. Wetlands in the Grove make

up a significant portion (12.3 percent) of the watershed. These wetlands provide important

hydrologic support including aquifer recharge, storm runoff abatement, sediment retention,

prevention of erosion through stream bank stabilization, and stream/river temperature moderation

in the watershed.

Mariposa Grove wetlands have very high biotic functions and values. This area contains a rich 

mosaic of old growth forest (with trees of all age classes, standing snags, and large downed trees),

streams, and wetlands. These habitats support a great variety of plant and wildlife species, including a

number of special­status species. These wetlands have high native plant productivity, cover, and

diversity. In addition, several fens, which have a limited distribution in the Sierra Nevada, are

present. Within 200 feet of delineated wetlands are located roughly 82 percent of the giant sequoias

(Kuhn 2011). This supports conclusions by Halpin (1995) on the importance of topographic flow

accumulation, and further signifies the importance of soil water availability within the rooting zone

Final Environmental Impact Statement 3­54 October 2013

Chapter 3: Affected Environment and

Environmental Consequences
     

               

   

         

                               

                             

                     

                               

                         

                               

                           

       

                         

                             

                       

     

                             

                               

                                 

    

                           

                

                     

Natural Resources: Wetlands

Restoration of the Mariposa Grove of Giant Sequoias

for giant sequoia. In the Mariposa Grove, 90.3 acres of palustrine forested wetland, 1.6 acres of

palustrine scrub shrub wetland, 8.8 acres of palustrine emergent forested wetland, and 2.0 acres of

riverine wetlands were delineated (figure 3­11). Although the National Wetland Inventory mapping

of the area identifies five separate palustrine emergent wetlands totaling 7.1 acres in the area, an

additional 1.6 acres were mapped during the field effort (NPS 2011f).These wetlands are continuous

along the dendritic network of perennial (6.1 miles) and seasonal (2.8 miles) streams that drain the

Grove, and which are incised in the gentle mountain topography (NPS 2011f). These features are

shown in figure 3­11.

The Mariposa Grove is almost entirely within a single, 877­acre, watershed sub­basin. This

watershed is within the mixed conifer forest zone. Soils are unglaciated residual and alluvial sandy

and silt loams with poor profile development, and are derived from granite and metasedimentary

bedrock.

South Entrance Setting

The South Entrance is within the same watershed sub­basin as the Mariposa Grove, but it is treated

as an additional 21 acres beyond the 877 acres delineated for the Grove. The South Entrance is

within the mixed conifer forest zone. Soils in the area are composed of sandy loam derived from

granitic bedrock.

A total of 1.4 acres of palustrine­forested wetland were delineated in and near the South Entrance

area (NPS 2011f), as shown in figure 3­12.

Figure 3­11 – Wetlands In and Near the Mariposa Grove

Final Environmental Impact Statement 3­55 October 2013

Chapter 3: Affected Environment and

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Natural Resources: Wetlands

Restoration of the Mariposa Grove of Giant Sequoias

Figure 3­12 – Wetlands at South Entrance

Environmental Consequences

Impact Assessment Methodology

Determination of the significance of potential impacts on wetlands was based on the duration, type

and intensity of impact. Actions that reduce the size or degrade the integrity or connectivity of

wetlands were considered adverse impacts, whereas actions that preserve, enhance, or restore these

qualities were considered beneficial impacts. For additional information on the assessment of

wetlands, refer to Appendix F, Draft Statement of Findings for Protection of Wetlands.

Impact Intensity Level Definitions

Negligible – Wetlands are not affected, or impacts do not result in a detectable change of wetland

function or value.

Minor – Impacts on wetlands are detectable and could result in a loss or gain of wetland function or

value. If compensatory mitigation is needed to reduce or rectify adverse impacts, it would be

relatively simple to implement and have a high probability of success.

Moderate – Impacts on wetlands are readily apparent and result in a loss or gain of wetland function

or value. Compensatory mitigation is probably necessary to reduce or rectify adverse impacts and

would have a high probability of success.

Major – Impacts on wetlands are readily apparent and substantially change the physical

characteristics of wetlands or result in a significant net loss or gain of wetland function or value.

Intensive compensatory mitigation is necessary to reduce or rectify adverse impacts, and its success

is not guaranteed.

Final Environmental Impact Statement 3­56 October 2013

Chapter 3: Affected Environment and

Environmental Consequences
     

               

   

         

       

                   

                         

                       

                       

                       

                         

                         

                               

                       

                        

                         

                         

                       

                 

                                 

                               

                                 

                     

                           

                       

               

                 

                           

                         

                           

                           

                                 

                               

                       

                                 

                             

          

                           

               

                         

                     

                   

                               

       

                       

                     

Natural Resources: Wetlands

Restoration of the Mariposa Grove of Giant Sequoias

Alternative 1: No Action

Under Alternative 1 current infrastructure, concessioner services and maintenance, and park

management would remain as is. No rehabilitation and restoration actions, such as improvement of

hydrologic flow and universal access, project­specific prescribed fire and hazardous fuel reduction

treatments, soil decompaction, and improvement of visitor orientation and interpretation, would be

implemented.

Operation­related Impacts. Continued use of the existing facilities at the Mariposa Grove could

result in inadvertent impacts on wetlands in the area from pedestrian trampling and disturbance

during recreational activities. These impacts would disturb the vegetation in the wetlands and could

affect the quality of the wetlands, but operational activities would be controlled in and around these

sensitive areas to minimize or prevent adverse impacts. With proper education and direction,

operational users would have a local, long­term, minor, adverse impact on wetlands.

Existing road design and alignment, impermeable surfaces (including park facilities), and trails would

continue to impair hydrologic connectivity, subsurface flow, and retention of available water within

the Mariposa Grove and degrade wetland communities. Specific facilities and structures impacting

hydrologic flow/process include: (1) forty­one roadway drainage culverts with diminished function

or capacity, and (2) about 11.3 acres of impermeable surfaces within the Mariposa Grove. As a result,

48.6 acres of surface water runoff is diverted from natural flow patterns within the Mariposa Grove

and 88.5 acres of surface water runoff is diverted from the Mariposa Grove. Road and parking area

stormwater runoff would continue to discharge waterborne pollutants directly into wetland

communities. In addition, the leaky water supply pipeline, which loses an estimated 39,000 gallons of

water per day within the Grove, may disrupt normal water supply patterns.

Impact Significance. Local, long­term, minor to moderate, adverse impacts.

Conclusion. No construction­related impacts would occur. Operation­related impacts would

include minor visitor impacts on wetlands and moderate adverse impacts to hydrologic flow and

processes.

Cumulative Impacts. The cumulative impacts on wetlands discussed in this section are based on an

analysis of past, present, and reasonably foreseeable future actions in the Yosemite region in

conjunction with the potential effects of Alternative 1 (No Action). Wetlands are the most altered

and impaired habitat of the Sierra Nevada, and, as a small proportion of the landscape, they are

relatively rare (SNEP 1996). Dams, roads, and water diversions in the Sierra Nevada have had a

profound effect on streamflow patterns and wetlands. Broad valleys with wide riparian wetlands

were often used as reservoir sites. Much of the flatwater on the western slope of the Sierra Nevada

below 5,000 feet in elevation is artificial. These past actions have had long­term, major adverse

effects on regional wetland habitat.

Current and future regional plans and projects would have beneficial and adverse impacts on

wetlands (Appendix B). Comprehensive Ecological Restoration Projects, the Wawona Meadow

Restoration Project, and ecological restoration elements of the Draft Merced and Tuolumne Wild and

Scenic River Comprehensive Management Plans would result in beneficial impacts on wetlands. The

Wilderness Stewardship Plan could contribute watershed­scale protection to wetlands in much of the

park, depending on the outcome of the final plans. These actions would have a long­term moderate

beneficial effect on wetlands.

There would be adverse impacts on wetlands associated with the current South Entrance Station

Kiosks Replacement project and future actions associated with new development proposed in the

Final Environmental Impact Statement 3­57 October 2013

Chapter 3: Affected Environment and

Environmental Consequences
     

               

   

         

                     

                         

                         

                   

                       

                   

                               

                               

                             

                             

                           

                         

                           

                             

         

           

                             

                         

                       

                       

                     

                 

                               

                             

                               

                               

                         

                               

                         

                             

      

                           

                   

                       

                               

                   

                             

                             

                               

                         

                           

                        

                       

                     

                   

Natural Resources: Wetlands

Restoration of the Mariposa Grove of Giant Sequoias

Draft Merced and Tuolumne Wild and Scenic River Comprehensive Management Plans, due to the

direct loss of wetlands. Site­specific adverse effects would be short­term (during construction) and

long­term (direct displacement of wetlands). The NPS will compensate for impacts on wetlands

associated with the South Entrance Station Kiosks Replacement project with wetland restoration in

the Mariposa Grove Plan/FEIS (Appendix F). Wetland impacts associated with in the Draft Merced

and Tuolumne Wild and Scenic River Comprehensive Management Plans would require compensation.

The NPS will consult with the U.S. Army Corps of Engineers and Regional Water Quality Control

Boards to ensure adequate compensation and no net loss of wetlands. The NPS will obtain required

Clean Water Act Section 401 and 404 permits prior to implementing any actions regarding wetlands.

In summary, past impacts on wetlands in the region have been adverse, long­term, and major.

Present and foreseeable future actions would contribute to reversing the adverse impacts of past

actions in the region, particularly within Yosemite. Past, present, and future impacts, in conjunction

with the minor impacts on wetlands and moderate impairments to hydrologic flows in the Mariposa

Grove under Alternative 1 (No Action), would result in a long­term moderate adverse impact on

wetlands in the Yosemite region.

Alternative 2: South Entrance Hub (Preferred Alternative)

Alternative 2 would remove the commercial tram operation and reduce the amount of lower Grove

parking while expanding and relocating primary visitor parking to the South Entrance, making the

South Entrance the departure point for visitors accessing the Grove. Rehabilitation and restoration

actions, such as improvement of hydrologic flow, project­specific prescribed fire and hazardous fuel

reduction treatments, and soil decompaction would be components of this alternative.

Construction­related Impacts. Under Alternative 2 (preferred alternative), wetlands loss is

estimated to total 0.37 acre. This total includes 0.24 acre of permanent wetland loss near the South 

Entrance due to construction activities and a very minor loss of wetlands (<0.01 acre) associated with 

restoration of impacted wetland and riparian habitat due to the installation of small piers to extend

the existing footbridge in the lower Grove area to protect the wetland from trampling impacts, and

replacement of drainage culverts with larger culverts to accommodate larger flows. Relocation of the

water tank, which is designed with an overflow to prevent freezing, could dry up a small wetland area

near the current tank location (0.10 acre). Artificially created roadside wetlands, resulting from

berms and failed culverts, would potentially dry up once flows are restored to natural drainage

patterns (<0.02 acre).

There would also be site­specific temporary impacts on wetlands during the construction phase. The

removal of impervious surfaces associated with existing buildings could temporarily increase

groundwater infiltration by exposing soils. A temporary change in surface runoff during

construction would not be noticeable in the Mariposa Grove and would have a minimal effect on

function or value of the wetlands in the Mariposa Grove.

There would be temporary minor adverse impacts in the lower Grove area during removal of

infrastructure and in the upper Grove area during water line repair and/or replacement. The repair

of leaking water pipes could have small local impacts on water tables, as it would eliminate

unintended leakage. It is difficult to quantify or locate site­specific underground leaks in such a

complex and large system, but overall, replacement of water lines could contribute to localized

minor decreases in water levels, leading to restoration of natural water levels.

No construction equipment staging areas would be adjacent to or within any wetlands.

Implementation of construction Best Management Practices would be employed to minimize

impacts associated with erosion and sedimentation. These Best Management Practices would

Final Environmental Impact Statement 3­58 October 2013

Chapter 3: Affected Environment and

Environmental Consequences
     

               

   

         

                               

                               

             

             

                 

                         

                           

                         

                             

                             

                                 

                         

    

           

                     

                         

                   

                             

                  

             

                           

                 

                                    

                         

                             

                           

                           

                       

                           

    

                 

                             

                         

                           

                               

                       

         

                             

                                   

                               

                                

                           

Natural Resources: Wetlands

Restoration of the Mariposa Grove of Giant Sequoias

include, but not be limited to, installation of silt fencing and sediment traps, application of water

sprays to keep soil from becoming airborne, and revegetation of disturbed areas as soon as possible,

where appropriate.

Impact Significance. Local, long­term, moderate, adverse impact on wetlands.

Restoration­related Impacts. Increasing the capacity of drainage culverts and implementation of

sustainable stormwater strategies would improve hydrologic connectivity, restore subsurface flows,

and retain water within the Mariposa Grove, which would restore processes that sustain wetland

ecosystems. In the long term, removal of facilities and elimination of associated uses such as

commercial tram service from the Mariposa Grove would protect and restore wetland habitat.

Realignment of the Grove road northward out of the delineated wetland, and conversion of the

original alignment to an accessible trail, would beneficially impact wetlands in that portion of the

Grove. The conversion of much of the upper Grove loop road to a trail would also restore some

palustrine forested wetland. Overall, about 1.0 acre of wetland restoration is anticipated under

Alternative 2.

Impact Significance. Long­term, major, beneficial impact on wetlands.

Operation­related Impacts. Closing the existing road in the Mariposa Grove would reduce

operation activities and reduce the potential for inadvertent impacts on wetlands from trampling,

although some recreational foot traffic in nearby wetlands would continue. Discharge of waterborne

pollutants from directly into wetland communities from road and parking areas would be reduced in

the Mariposa Grove, but would increase at the South Entrance.

Impact Significance. Local, long­term, minor, adverse impact on wetlands.

Conclusion. Alternative 2 is expected to have a local, short­term minor adverse impact from

potential soil erosion associated with construction­related impacts. Construction activities would

result in the loss of about 0.24 acre of wetland at the South Entrance. Alternative 2 is expected to

have long­term major beneficial impacts on wetlands from the removal of facilities and subsequent

ecological restoration (1.0 acre), vehicular traffic, and the improvement of water flows in the Grove

that sustain wetlands. Overall, there would be a long­term, moderate beneficial impact on wetlands.

Adherence to mitigation measures described in Chapter 2 and Appendix E and avoidance of

wetlands where possible would minimize short­term impacts. Appendix F, Draft Statement of

Findings for Protection of Wetlands, provides additional detail on potential impacts on wetlands and

mitigation measures.

Cumulative Impacts. The regional past, present, and reasonably foreseeable projects affecting

wetlands would be the same as those under Alternative 1 (No Action)—an overall long­term major

adverse impact on wetlands in the Yosemite region. These impacts, in conjunction with the longterm moderate beneficial impacts of Alternative 2 on wetlands in the Mariposa Grove, would

contribute to reversing the adverse impacts of past actions in the region. On a regional scale, longterm moderate adverse impacts on wetlands in the Yosemite region would continue.

Alternative 3: Grizzly Giant Hub

Alternative 3 would remove the commercial tram operation and build a new bypass road, including

two new bridges, and a new larger parking lot near the Grizzly Giant, but outside of giant sequoia

habitat. The Grizzly Giant would be the primary departure point for visitors to the Grove. The

current number of parking spaces at the South Entrance would remain as is, and the lower Grove

parking lot would be removed. A small lot of ABAAS­compliant parking spaces would be

Final Environmental Impact Statement 3­59 October 2013

Chapter 3: Affected Environment and

Environmental Consequences
     

               

   

         

                         

                       

                 

                           

                         

                                 

                           

                       

                             

    

                           

                   

                       

                               

                   

                             

                             

                               

                         

                           

                         

                         

                     

                           

                               

                     

           

             

                 

                         

                           

                         

                               

                             

                               

                           

           

                     

                         

                   

                             

                    

             

Natural Resources: Wetlands

Restoration of the Mariposa Grove of Giant Sequoias

constructed in the lower Grove area. Rehabilitation and restoration actions, such as improvement of

hydrologic flow, project­specific prescribed fire and hazardous fuel reduction treatments, and soil

decompaction would be similar to those in Alternative 2 South Entrance.

Construction­related Impacts. Under Alternative 3, a total of about 0.03 acre in wetland loss would

be anticipated. There would be a very minor loss of wetlands (<0.01 acre) associated with restoration

of impacted wetland and riparian habitat due to the installation of small piers to extend the existing

footbridge in the lower Grove area to protect the wetland from trampling impacts, and replacement

of drainage culverts with larger culverts to accommodate larger flows. Artificially created roadside

wetlands, resulting from berms and failed culverts, would potentially dry up once flows are restored

(<0.02 acre).

There would also be site­specific temporary impacts on wetlands during the construction phase. The

removal of impervious surfaces associated with existing buildings could temporarily increase

groundwater infiltration by exposing soils. A temporary change in surface runoff during

construction would not be noticeable in the Mariposa Grove and would have a minimal effect on

function or value of the wetlands in the Mariposa Grove.

There would be temporary minor adverse impacts in the lower Grove area during removal of

infrastructure and in the upper Grove area during water line repair and/or replacement. The repair

of leaking water pipes could have small local impacts on water tables, as it would eliminate

unintended leakage. It is difficult to quantify or locate site­specific underground leaks in such a

complex and large system, but overall, replacement of water lines could contribute to localized

minor decreases in water levels, leading to restoration of natural water levels. No construction

equipment staging areas would be adjacent to or within any wetlands. Implementation of

construction Best Management Practices would be employed to minimize impacts associated with 

erosion and sedimentation. These Best Management Practices would include, but not be limited to,

installation of silt fencing and sediment traps, application of water sprays to keep soil from becoming

airborne, and revegetation of disturbed areas as soon as possible, where appropriate.

Impact Significance. Local, short­term, minor, adverse impact on wetlands.

Restoration­related Impacts. Increasing the capacity of drainage culverts and implementation of

sustainable stormwater strategies would improve hydrologic connectivity, restore subsurface flows,

and retain water within the Mariposa Grove, which would restore processes that sustain wetland

ecosystems. In the long term, removal of facilities and elimination of associated uses such as

commercial tram service from the Mariposa Grove would protect and restore wetland habitat.

Removal of the Grove road out of the delineated wetland, and conversion of the original alignment

to an accessible trail, would beneficially impact wetlands in that portion of the Grove. The

conversion of much of the upper Grove loop road to a trail would also restore some palustrine

forested wetland. Overall, about 1.0 acre of wetland restoration is anticipated under Alternative 3.

Impact Significance. Long­term, major, beneficial impact on wetlands.

Operation­related Impacts. Closing the existing road in the Mariposa Grove would reduce

operation activities and reduce the potential for inadvertent impacts on wetlands from trampling,

although some recreational foot traffic in nearby wetlands would continue. Discharge of waterborne

pollutants from directly into wetland communities from road and parking areas would be reduced in

the Mariposa Grove, but would increase near the Grizzly Giant.

Impact Significance. Local, long­term, minor, adverse impact on wetlands.

Final Environmental Impact Statement 3­60 October 2013

Chapter 3: Affected Environment and

Environmental Consequences
     

               

   

         

                             

                       

                       

                             

                           

                           

              

                 

                             

                         

                             

                               

                     

                   

                             

                         

                           

                       

                   

            

                         

                             

                             

                               

                               

                         

                                 

                           

                        

                           

                   

                       

                               

                   

                             

                             

                               

                         

                           

                        

                       

                     

                   

                               

Natural Resources: Wetlands

Restoration of the Mariposa Grove of Giant Sequoias

Conclusion. Alternative 3 would be expected to have a local, short­term minor adverse impact from

potential soil erosion associated with construction­related impacts. Alternative 3 is expected to have

long­term major beneficial impacts on wetlands from the removal of facilities and subsequent

ecological restoration (1.0 acre), vehicular traffic, and the improvement of water flows in the Grove

that sustain wetlands. Overall, there would be a long­term, major beneficial impact on wetlands.

Adherence to mitigation measures described in Chapter 2 and Appendix E and avoidance of

wetlands where possible would minimize short­term impacts.

Cumulative Impacts. The regional past, present, and reasonably foreseeable projects affecting

wetlands would be the same as those under Alternative 1 (No Action)—an overall long­term major

adverse impact on wetlands in the Yosemite region. These impacts, in conjunction with the longterm major beneficial impacts of Alternative 3 on wetlands in the Mariposa Grove, would contribute

to reversing the adverse impacts of past actions in the region. On a regional scale, long­term

moderate adverse impacts on wetlands in the Yosemite region would continue.

Alternative 4: South Entrance Hub with Modified Commercial Tram Service

Alternative 4 would maintain the commercial tram but with a limited route and hours of operation

while also relocating the majority of the parking to the South Entrance, making the South Entrance

the primary departure point for visitors to the Grove. Numerous other rehabilitation and restoration

actions, such as improvement of hydrologic flow, project­specific prescribed fire and hazardous fuel

reduction treatments, soil decompaction, and improvement of visitor orientation and interpretation,

would be components of this alternative.

Construction­related Impacts. Under Alternative 4, wetlands loss is estimated to total 0.37 acre, the

same as Alternative 2. This total includes 0.24 acre of permanent wetland loss near the South 

Entrance due to construction activities and a very minor loss of wetlands (<0.01 acre) associated with 

restoration of impacted wetland and riparian habitat due to the installation of small piers to extend

the existing footbridge in the lower Grove area to protect the wetland from trampling impacts, and

replacement of drainage culverts with larger culverts to accommodate larger flows. Relocation of the

water tank, which is designed to overflow to prevent freezing, could dry up a small wetland area near

the current tank location (0.10 acre). Artificially created roadside wetlands, resulting from berms and

failed culverts, would potentially dry up once flows are restored (<0.02 acre).

There would also be site­specific temporary impacts on wetlands during the construction phase. The

removal of impervious surfaces associated with existing buildings could temporarily increase

groundwater infiltration by exposing soils. A temporary change in surface runoff during

construction would not be noticeable in the Mariposa Grove and would have a minimal effect on

function or value of the wetlands in the Mariposa Grove.

There would be temporary minor adverse impacts in the lower Grove area during removal of

infrastructure and in the upper Grove area during water line repair and/or replacement. The repair

of leaking water pipes could have small local impacts on water tables, as it would eliminate

unintended leakage. It is difficult to quantify or locate site­specific underground leaks in such a

complex and large system, but overall, replacement of water lines could contribute to localized

minor decreases in water levels, leading to restoration of natural water levels.

No construction equipment staging areas would be adjacent to or within any wetlands.

Implementation of construction Best Management Practices would be employed to minimize

impacts associated with erosion and sedimentation. These Best Management Practices would

include, but not be limited to, installation of silt fencing and sediment traps, application of water

Final Environmental Impact Statement 3­61 October 2013

Chapter 3: Affected Environment and

Environmental Consequences
     

               

   

         

                               

             

             

                 

                         

                           

                         

                             

                             

                                 

                         

           

                     

                         

                   

                             

                  

             

                           

                 

                                    

                           

                               

                         

                             

    

                 

                             

                         

                           

                               

                       

     

                     

                         

                             

                         

                             

                           

                            

Natural Resources: Wetlands

Restoration of the Mariposa Grove of Giant Sequoias

sprays to keep soil from becoming airborne, and revegetation of disturbed areas as soon as possible,

where appropriate.

Impact Significance. Local, long­term, moderate, adverse impact on wetlands.

Restoration­related Impacts. Increasing the capacity of drainage culverts and implementation of

sustainable stormwater strategies would improve hydrologic connectivity, restore subsurface flows,

and retain water within the Mariposa Grove, which would restore processes that sustain wetland

ecosystems. In the long term, removal of facilities and elimination of associated uses such as

commercial tram service from the Mariposa Grove would protect and restore wetland habitat.

Realignment of the Grove road northward out of the delineated wetland, and conversion of the

original alignment to an accessible trail, would beneficially impact wetlands in that portion of the

Grove. The conversion of much of the upper Grove loop road to a trail would also restore some

palustrine forested wetland. Overall, the area of wetland restoration would total 0.77 acre.

Impact Significance. Long­term, major, beneficial impact on wetlands.

Operation­related Impacts. Closing the existing road in the Mariposa Grove would reduce

operation activities and reduce the potential for inadvertent impacts on wetlands from trampling,

although some recreational foot traffic in nearby wetlands would continue. Discharge of waterborne

pollutants from directly into wetland communities from road and parking areas would be reduced in

the Mariposa Grove, but would increase at the South Entrance.

Impact Significance. Local, long­term, minor, adverse impact on wetlands.

Conclusion. Alternative 4 is expected to have a local, short­term minor adverse impact from

potential soil erosion associated with construction­related impacts. Construction activities would

result in the loss of about 0.24 acre of wetland at the South Entrance. Alternative 4 is expected to

have long­term major beneficial impacts on wetlands from the removal of facilities, vehicular traffic,

and the improvement of water flows in the Grove that sustain wetlands (0.77 acre). Overall, there

would be a long­term, moderate beneficial impact on wetlands. Adherence to mitigation measures

described in Chapter 2 and Appendix E and avoidance of wetlands where possible would minimize

short­term impacts.

Cumulative Impacts. The regional past, present, and reasonably foreseeable projects affecting

wetlands would be the same as those under Alternative 1 (No Action)—an overall long­term major

adverse impact on wetlands in the Yosemite region. These impacts, in conjunction with the longterm moderate beneficial impacts of Alternative 4 on wetlands in the Mariposa Grove, would

contribute to reversing the adverse impacts of past actions in the region. On a regional scale, longterm moderate adverse impacts on wetlands in the Yosemite region would continue.

HYDROLOGY AND WATER QUALITY

Affected Environment

The NPS Freshwater Resource Management Guidelines in Natural Resource Management Reference

Manual #77 requires the park service to “maintain, rehabilitate, and perpetuate the inherent integrity

of water resources and aquatic ecosystems.” Yosemite National Park has a variety of surface water

features originating from snowmelt atop the High Sierra, some of which are major attractions for

visitors, such as Yosemite Falls. Precipitation in the lower elevations occurs either as rain or snow,

which melts quickly and flows into streams. At higher altitudes, precipitation usually occurs as snow,

which melts more slowly and sustains surface water flows during the spring and early summer.

Final Environmental Impact Statement 3­62 October 2013

Chapter 3: Affected Environment and

Environmental Consequences
           

               

   

         

                           

                           

                                       

          

                             

                         

                           

                       

                               

                   

                             

                                 

                                 

                           

                                   

                                 

                             

                        

      

             

                   

                       

                 

                       

                       

               

    

                         

             

                   

                 

               

                 

                     

                         

                   

               

                 

                 

                       

                         

          

                             

                           

                     

                             

                             

     

Natural Resources: Hydrology and Water Quality

Restoration of the Mariposa Grove of Giant Sequoias

About 85 percent of the park’s precipitation falls between November and April. December, January,

and February have the highest average precipitation. Average annual precipitation is 25 inches in

El Portal at 2,000 feet, 36.5 inches in Yosemite Valley at 4,000 feet, and increases to 70 inches at 6,000

to 8,000 feet (Eagan 1998).

Yosemite National Park is drained by two major watersheds: the Tuolumne and the Merced, both of

which are sub­basins of the San Joaquin River Hydrologic Region. Both rivers are designated as

National Wild and Scenic Rivers and are therefore administered with the goal of protecting and

enhancing the outstandingly remarkable values that caused them to be designated. Federal support

for actions such as the construction of dams or other in­stream activities that would harm the river’s

free­flowing condition, water quality, or outstandingly remarkable values is prohibited. The

Tuolumne and Merced river systems originate along the crest of the Sierra Nevada, carving and

occupying glacially excavated river canyons that are now 3,000 to 4,000 feet deep, on their paths to

the Central Valley. The Tuolumne River drains the entire northern portion of the park, an area of

approximately 435,000 acres (681 square miles). The Merced River basin begins in the southern

region of the park and drains the southern one­third of the park, or 250,000 acres (391 square miles)

within the boundaries of the park. The Mariposa Grove lies above and to the south of the South Fork

of the Merced River. Yosemite National Park is within the Yosemite Valley Groundwater Basin of

the San Joaquin River Hydrologic Region (California Department of Water Resources 2003).

Mariposa Grove Setting

The 704­acre (1.1­square­mile) Mariposa Grove is wholly

within the South Fork Merced River drainage. The low point of

the watershed within the Grove is near the main entrance to the

Grove and is approximately 5,479 feet in elevation. The high 

point of the Grove is near the fallen Wawona Tunnel Tree and

is 6,988 feet in elevation. The Grove is divided into two main

watershed areas: the upper Grove and lower Grove

(figure 3­13).

The topography of the Grove can be thought of as the back of a

three­fingered hand with the ridges (fingers) pointing (and

dipping) to the southwest. These three fingers are the dominant

ridges of the Grove. Using this back­of­the­hand analogy, the

upper Grove area is where two dominant “knuckles”

(6,447­foot elevation knolls) and the lesser knuckle of the

“forefinger” continue up to a flatter area at the 6,562­foot level.

Here the upper loop road makes a circle in the flattened area of

the “back of the hand.” The upper Grove watershed is

approximately 410 acres and includes Rattlesnake Creek, the

two prominent knuckles described above, and the flat area

containing upper Grove loop road. The lower Grove watershed

is 315 acres, and the Clothespin Tree is a high point near its

northwestern corner. The lower Grove area drains into an unnamed creek that joins with 

Rattlesnake Creek south of the Grove.

Surface features within the drainage area include approximately 6.1 miles of perennial and 2.8 miles

of intermittent drainage channels (figure 3­14). Water regimes of the Grove tend to sustain perennial

surface flow and shallow groundwater throughout much of the year. Riparian communities and

floodplains are primarily linear features that are constricted to the stream corridor by steep upland

slopes. Results from a generalized spatial analysis of percent­slope values in the upper and lower

Figure 3­13 – Perennial Stream in Mariposa

Grove

Final Environmental Impact Statement 3­63 October 2013

Chapter 3: Affected Environment and

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Natural Resources: Hydrology and Water Quality

Restoration of the Mariposa Grove of Giant Sequoias

portions of the Grove drainage area are presented in table 3­3. Topographic relief in the Grove is

generally moderate, averaging 14 percent overall. Slope values within the upper and lower Grove

areas are not substantially different, with mean values of 40 percent and 44 percent maximum slopes,

respectively.

Figure 3­14 – Mariposa Big Trees Watershed and Surrounding Watersheds

Table 3­3 – Topographic Relief of the Mariposa Grove Area

Observed Values Summary Statistics

Minimum

Slope

(%)

Maximum

Slope

(%)

Minimum

Slope Mean

(%)

Maximum

Slope Mean

(%)

Mean Slope

(Standard 

Deviation)

(%)

Lower Grove 0.01 73.40 0.21 44.25 14.43 (1.64)

Upper Grove 0.01 64.88 0.17 40.34 13.61 (1.12)

The Grove is in a Mediterranean climate regime, where precipitation occurs primarily during the

cool winter season. Summers are hot and dry with only occasional rainfall from orographic

thunderstorms. The Grove’s elevation lies in the transition zone between systems dominated by

winter rain or snow (Stephenson et al. 1988). As such, aspects of the Grove’s water regime may be

vulnerable to climate change due to earlier timing of snow melt and a general increase in the

elevation at which snow accumulates (NPS 2012b). Overlaying PRISM Climate Group (2011) data

from 1971 to 2000 on the Grove drainage area indicates that mean annual precipitation ranges from

47 to 49 inches. These values are consistent with, though slightly greater than, those recorded at the

South Entrance meteorological station; the differences are attributable to differences in elevation

between the Grove and the South Entrance (see table 3­4).

Final Environmental Impact Statement 3­64 October 2013

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Natural Resources: Hydrology and Water Quality

Restoration of the Mariposa Grove of Giant Sequoias

Table 3­4 – Climate Summary for the South Entrance (Station 048380), 1941­2011

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual

Mean Total 

Precipitation

(in.)

8.56 7.22 6.58 3.72 1.74 0.58 0.12 0.1 0.65 2.32 5.13 7.04 43.76

Mean Max.

Temperature

(°F)

46.3 47.9 50.3 56.2 65 73.9 82 81.2 76 65.9 54.4 47.9 62.3

Mean Min.

Temperature

(°F)

25.7 26.4 27.8 31.1 37.3 43.7 49.4 48.5 44.5 37.2 30.3 26.4 35.7

Mean Total 

Snow Fall 

(in.)

20.7 20.3 23.5 11.1 1.2 0.1 0 0 0 0.4 6.5 16.7 100.5

Mean Snow

Depth (in.) 8 9 7 2 0 0 0 0 0 0 1 4 3

Source: Western Regional Climate Center 2012

Surface hydrology in this area includes approximately 6.1 miles of perennial and 2.8 miles of

intermittent drainage channels, and the occurrence of small emergent palustrine forested wetlands

along channel floodplain areas (NPS 2011f). Runoff from rain or snowmelt originating from the

Mariposa Grove is intercepted by several creeks flowing generally southwest and eventually

discharging to the South Fork of the Merced River. The flatter topography and coarse granitic soils

of the upper Grove area facilitate the percolation (infiltration) of stormwater and snowmelt to

contribute to the groundwater. Infiltrating precipitation travels downward through the coarse,

granitic soils to the saturated zone, where it flows along a topographically driven pressure gradient.

Shallow groundwater discharges to the ground surface in low­lying creeks and wetlands, and as

seeps along road cuts and natural embankments. Groundwater and surface water hydraulic gradients

are toward Rattlesnake Creek and other tributaries, and then to the South Fork Merced River.

Subsurface flow occasionally infiltrates deeper into the granite bedrock via fracture flow. Although 

depths to groundwater and bedrock have not been measured in the Mariposa Grove, seasonal

fluctuations are likely. Soils mapped by the U.S. Department of Agriculture (2012) are described as

having 80­inch or greater depths to the water table or restrictive feature.

The undisturbed (pre­development) hydrologic condition within the Mariposa Grove was

characterized by widespread overland flow and infiltration into subsurface soil horizons. Soil

moisture and shallow groundwater have likely been key factors in sustaining the Grove ecosystem

over time. Pre­development, soil compaction was limited to natural processes, and duff/litter

accumulation was regulated by the vegetative production and decomposition via natural processes

such as microfloral and faunal activity, and the natural and prehistoric/proto­historic anthropogenic

fire regimes. The high nutrient content and substantial water­retention capacity of a thick duff/litter

layer provides slow release of nutrient­rich moisture to the plant root­zone. Wetlands and shallow

groundwater seepage likely buffered surface erosion by reducing the magnitude and velocity of peak

runoff flows.

Mariposa Grove hydrology has been modified as a result of historic logging and more recent

development to accommodate park visitors. Construction of trails, roads, utilities, and other

infrastructure resulted in the blockage and alteration of both surface runoff and shallow

groundwater flow patterns (figure 3­15).

Final Environmental Impact Statement 3­65 October 2013

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Natural Resources: Hydrology and Water Quality

Restoration of the Mariposa Grove of Giant Sequoias

Figure 3­15 – Culvert Function Status and Redirected and Lost Flow within the Mariposa Grove

Contemporary hydrologic conditions are highly

disturbed by soil compaction and the road/trail drainage

system and largely dominated by rapid surface runoff

and channelized flows (figure 3­16) (Entrix 2007). Travel

times for water moving through the watershed are

substantially reduced (Entrix 2007) from predevelopment values. As a result, soil moisture and

shallow groundwater availability may be reduced. A

leaking pipeline system that conveys drinking water from

Biledo Spring on U.S. Forest Service land to the Grove

and the South Entrance loses an estimated 39,500 gallons

per day (44 acre­feet per year) within the upper Grove

area, and likely percolates to the upper Grove wetland.

An additional 500 to 1,500 gallons per day (0.6 to

1.7 acre­feet per year), depending upon level of use, is

also contributed to the upper Grove wetland from water

percolation through the upper Grove leach field. In

addition, fire suppression practices may have altered

plant composition and structure within the Mariposa

Grove, and may have affected the water balance by

increasing evapotranspiration and changing the

distribution, volume, and persistence of snowpack

accumulation and runoff infiltration (NPS 2012b).

Figure 3­16 – Drainage Channel along the

Mariposa Grove Road within the Grove

Final Environmental Impact Statement 3­66 October 2013

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Restoration of the Mariposa Grove of Giant Sequoias

Infrastructure Affecting Hydrology

The Mariposa Grove contains roughly 6.8 miles of developed (paved) secondary roadways, 0.3 mile

of compacted dirt road, and 1.6 acres of paved parking areas (NPS 2012b). The paved road network

extends throughout the drainage area for the Grove—extending from the watershed outlet to its

highest elevation at Wawona Point. This road network is used for administrative access and

concessioner­based transport of visitors via commercial tram throughout the Grove. The roadways

are generally 20 to 25 feet wide, with the single­lane segments that comprise the upper Grove loop

averaging roughly 10 feet wide. In addition, three abandoned unnamed roads are within the Grove

(Entrix 2007). The first abandoned road is south of the Grizzly Giant parking lot and extends

roughly 150 feet from the main road. This road leads into the Rainer Creek watershed. Another

abandoned road is approximately 200 feet long and is a former parking area west of the Grove

museum; this section is now used as part of the pedestrian trail system. A third abandoned road is

roughly 100 feet in length and is east of the fallen Wawona Tunnel Tree along the upper Grove loop.

Roughly 10 miles of unpaved pedestrian hiking trails have been established throughout the Grove;

notably, many of these trails are former road grades that have since been restricted to foot traffic

(NPS 2012b). Heavily used formal trails range in length and are typically 9 to 14 feet wide with base

rock or compacted native soil; lesser­used interior and outer loop trails are extensive in length but

typically range from 2 to 3 feet in width. Soil compaction has been exacerbated by repeated use of

informal social trails throughout the Grove and at the bases of many adult giant sequoia trees. The

use of off­road parking areas for administrative and concessioner staff vehicles, such as the

commercial tram parking/storage area in the lower Grove area, further contributes to soil

compaction.

Additional hardscape features (i.e. impermeable surfaces) within the drainage area for the Grove

include lower Grove facilities—restrooms, information kiosk, and gift shop; upper Grove facilities—

a small museum and associated restrooms (both vault and flush toilets); and a communications tower

(cellular tower and radio repeater) and equipment enclosure positioned at Wawona Point in the

uppermost area of the watershed (NPS 2012b). Supporting infrastructure for these facilities includes

roughly 1,300 feet of pipeline associated with the septic system and leach field for the flush toilets in

the upper Grove area, water tanks, and roughly 4,800 feet of water pipeline associated with water

supply from Biledo Springs (on U.S. Forest Service land within the Rainer Creek watershed) to the

Mariposa Grove and the South Entrance facilities (NPS 2012b).

Spring water from Biledo Springs is pumped into the water storage tanks, where it is treated by an

onsite chlorination unit, and then distributed to the Mariposa Grove and South Entrance facilities

via the distribution pipeline system. The water tanks are overfilled during the winter to induce

overflow conditions that prevent freezing. This overflow discharges onto the ground surface. The

water distribution system piping currently is leaking at a rate of approximately 39,500 gallons per day

within the upper Grove area (NPS 2012b). The leaking, chlorinated water discharges to the upper

Grove wetland and into the subsurface in the drainage course that the piping follows.

Luce and Wemple (2001) note that the influence of the linear design of road systems on watershedscale hydrologic processes is disproportionately greater than the small percentage of land area that

roads occupy would suggest. Most road prisms bisect hill slopes and act as networks that block

overland sheet flow and redirect it into roadside ditches. In­sloped roads with associated cut­ and

fill­slopes are particularly disruptive of the natural surface flow regime; intercepted surface runoff is

redirected as channelized flow along road surfaces and in road drainage ditches. In this manner, road

networks effectively extend surface channel networks and increase drainage density, thereby

increasing the routing efficiency of water out of a given watershed (Wemple et al. 1996) and

decreasing opportunities for groundwater recharge.

Final Environmental Impact Statement 3­67 October 2013

Chapter 3: Affected Environment and

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Natural Resources: Hydrology and Water Quality

Restoration of the Mariposa Grove of Giant Sequoias

There are 6.1 miles of perennial streams and 2.8 miles of intermittent drainage channels within the

Grove (NPS 2012b). Sixty­four culverts (Entrix 2007) are on these streams to convey surface flow

under or around the road and trail network to facilitate visitor use while controlling erosion and

sedimentation. Comprehensive mapping and evaluation of these culverts were completed in 2007.

This study revealed that many of the culverts needed replacing for a variety of reasons. Some were

undersized for their water and sediment loads; some were undersized solely from a water­volume

standpoint; and some were structurally failing. Many were plugged, primarily due to some of the

deficiencies noted above, and possibly because they were not set on a gradient steep enough to

transport the sediment delivered to the inlet. The lengths of channels formed by discharge from

these culverts have increased considerably, and channelization has effectively divided the primary

Grove watersheds into 53 sub­drainage basins (Entrix 2007). Surface runoff from approximately

50 acres is diverted from its natural flow pattern within the upper Grove area, and surface runoff

from approximately 90 acres (12 percent of Grove drainage area) is diverted from the Grove entirely.

Approximately 10 percent of the drainage area’s precipitation is currently lost because of poor

culvert function and diversion of flow out of the Grove via the roadway ditches. Approximately

90 acres of the watershed no longer contribute runoff to giant sequoia habitat within the Grove.

South Entrance Setting

The South Entrance is downstream of the Grove at an elevation of approximately 5,100 feet.

Infrastructure at the South Entrance includes the paved Wawona Road, the South Entrance kiosks,

restroom, and ranger housing facilities. Abandoned wagon and logging roads are evident through 

portions of the South Entrance area. A generalized spatial analysis of percent­slope indicates that

grades in the area are less steep than in the Grove and range from 3 to 17 percent, with an average of

roughly 8.5 percent (NPS 2012b). This area receives drinking water from Biledo Spring via a

distribution pipeline. A leach field that serves the South Entrance comfort station and ranger

residence likely contributes to local shallow groundwater mounding.

Water Quality

Water quality studies within the drainage areas of the Mariposa Grove and South Entrance are

limited. Table 3­5 presents data collected near the Grizzly Giant from 1981­1983 (NPS 1994).

Table 3­5 – Water Quality Data for Station YOSE007 near Grizzly Giant, 1981­1983

Parameter Mean Maximum Minimum

Temperature (°C) 15.0 15.0 15.0

Stream Flow (cfs) 0.09 0.09 0.09

Specific Conductance (μmhos/cm @ 25°C) 79.0 98.0 60.0

Dissolved Oxygen (mg/L) 8.0 9.0 7.0

pH 7.1 7.9 6.3

Carbon Dioxide (mg/L) 24.0 24.0 24.0

Alkalinity (mg/L of CACO3) 28.5 30.0 27.0

Nitrite and Nitrate (mg/L) 0.018 0.03 0.005

Phosphorus (mg/L) 0.013 0.024 0.003

Fecal Coliform, 0.7­μm MF (col./mL) 4.25 8.0 0.5

Log Fecal Coliform, 0.7­μm MF (col./mL) 0.301 0.903 0.301

Final Environmental Impact Statement 3­68 October 2013

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Vehicle use and the diesel­fueled gift shop generator may release metals and petroleum­based

hydrocarbons into the environment. There currently are no engineered stormwater treatment best

management practices (BMPs) such as bioswales or water quality basins at parking areas or along

roads; however, most pollutants are likely absorbed into the soil or taken up by vegetation along the

way to receiving waters. The septic system and leach fields in the upper Grove area and at the South 

Entrance may percolate water with elevated nutrient (e.g., nitrogen) concentrations into the

subsurface; and storage tank overflow and leaking water distribution lines release chlorinated water

into wetlands and shallow groundwater. Pedestrian and vehicle traffic and poorly designed and

deteriorating culverts contribute to erosion and the resulting increased sediment loading in streams.

The Mariposa Grove drains to the South Fork of the Merced River, where surface water quality is

generally good. Similarly, the Merced River watershed is considered to have high­quality surface

water, with reportedly low dissolved solids, near­neutral pH, low alkalinity, low nutrient

concentration, and low microbial counts (Clow et al. 2011).

Environmental Consequences

Impact Assessment Methodology

Water resources analysis was based on a qualitative assessment of water resources and impacts likely

caused by construction, rehabilitation, operations, and maintenance activities at the Mariposa Grove

and the South Entrance.

Types of water resources impacts include adding constituents to water, such as sediment; loss of or

additions to the amount of water; changes in the flow rate or discharge of water; and impacts on

water­related resources, such as floodplains. Beneficial impacts would protect or improve natural

flow conditions, water quality, and/or water quantity. Beneficial impacts may include restoration,

such as elimination or containment of pollutant sources or removing impediments to flow (e.g.,

inefficient or blocked culverts). Adverse impacts would disrupt natural flow, degrade water quality,

and/or alter water quantity.

Impact Intensity Level Definitions

Negligible – Hydrology of the area would not be affected, or impacts would not be measurable. Any

impacts on the hydrologic regime would be slight and short­term. Water quality would not be

affected, or impacts would not be measurable and would not affect beneficial uses of receiving

waters.

Minor – Impacts on hydrology, such as an increase or decrease in surface or groundwater flow,

would be detectable. If mitigation were needed to offset adverse impacts, it would be relatively

simple to implement. Impacts on water quality would be detectable and could affect beneficial uses

of receiving waters. If mitigation is needed to offset adverse impacts, it would be relatively simple to

implement.

Moderate – Impacts on hydrology would be readily apparent. Mitigation would probably be

necessary to offset adverse impacts. Impacts on water quality would be readily apparent and would

affect beneficial uses of receiving waters. Mitigation would probably be necessary to offset adverse

impacts.

Major – Impacts on hydrology would be readily apparent and would substantially change the

hydrologic regime over the area. Similarly, impacts on water quality would be readily apparent and

would substantially change beneficial uses of surface or groundwater. Substantial mitigation would

probably be necessary to offset adverse impacts, and its success could not be guaranteed.

Final Environmental Impact Statement 3­69 October 2013

Chapter 3: Affected Environment and

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Natural Resources: Hydrology and Water Quality

Restoration of the Mariposa Grove of Giant Sequoias

Alternative 1: No Action

Under Alternative 1, current infrastructure, concessioner services and maintenance, and park

management would remain as is. No rehabilitation or restoration actions, such as improvement of

hydrologic flow and universal access, project­specific prescribed fire and hazardous fuel reduction

treatments, soil decompaction, and improvement of visitor orientation and interpretation, would be

implemented.

Operations­related Impacts. Under Alternative 1, existing trends in water quality improvement or

degradation would continue. There would continue to be direct and indirect increase in flow rates

and water quality degradation due to redirected and lost flow caused by blocked culverts and insloped roads and trails. Parking areas and roads would continue to contribute metals and petroleumbased hydrocarbons to stormwater runoff, although most of these pollutants would be absorbed by

soil or vegetation along the way to receiving waters. The septic systems and leach fields in the upper

Grove area and at the South Entrance would continue to contribute nutrient­enriched water to the

shallow groundwater system. The water supply pipeline would continue to leak 39,500 gallons per

day of chlorinated water in the upper Grove area. Maintenance, repair, and management of resource

impacts associated with the existing road drainage system, septic systems and leach fields, and water

supply pipelines would presumably occur as problem areas are identified, and treatment mitigations

would likely vary on a case­by­case basis.

Impact Significance. Regional, long­term, moderate, adverse impact.

Conclusion. No construction­related impacts would occur. Operations­related impacts would

include moderate erosion caused by a poorly designed road drainage system, and minor impacts on

water quality caused by failing leach fields and leaking chlorinated water pipelines. Diversion of

approximately 10 percent of Grove runoff to areas outside of the Grove would continue. Overall,

there would be a long­term moderate adverse impact on hydrology and water quality.

Cumulative Impacts. Cumulative impacts on hydrology and water quality are based on an analysis

of past, present, and reasonably foreseeable future actions in the Yosemite region in conjunction

with the potential effects of Alternative 1 (No Action). Dams, roads, and diversions in the Sierra

Nevada have had a profound effect on stream­flow patterns and wetlands in the region. Broad

valleys with wide riparian wetlands were often used as reservoir sites. These past actions have had

long­term, major adverse effects on regional hydrology; past impacts on water quality have been

negligible. Surface water quality in Yosemite is exceptionally high, and far superior to federal and

state standards.

Current and future regional plans and projects would have beneficial and adverse impacts on

hydrology or water quality (Appendix B). Comprehensive Ecological Restoration Projects, the

Wawona Meadow Restoration Project, and ecological restoration elements of the Draft Merced and

Tuolumne Wild and Scenic River Comprehensive Management Plans would result in beneficial impacts

on hydrology and water quality by improving natural flow conditions, removal of pollutant sources,

and improving floodplain conditions. The Wilderness Stewardship Plan could contribute watershedscale protection to hydrology and water quality, depending on the outcome of the final plan. These

actions would have a long­term moderate beneficial effect on hydrology and water quality.

There could be adverse impacts on hydrology and water quality associated with the current South 

Entrance Station Kiosks Replacement project and future actions associated with new development

proposed in the Draft Merced and Tuolumne Wild and Scenic River Comprehensive Management

Plans, due to the direct loss of wetlands, which serve as natural water filters. Site­specific adverse

effects could be short­term (during construction). The NPS will consult with the Regional Water

Final Environmental Impact Statement 3­70 October 2013

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Restoration of the Mariposa Grove of Giant Sequoias

Quality Control Board to maintain the highest possible water quality standards during

implementation of these projects. The NPS will obtain required Water Quality Certifications prior to

implementing related actions.

In summary, past impacts on hydrology in the region have been adverse, long­term, and major;

impacts on water quality have been negligible. Present and foreseeable future actions would

contribute to reversing the adverse impacts of past actions in the region. The impacts of Alternative 1

(No Action) on hydrology and water quality would be moderate adverse due to erosion associated

with the road system, failing leach fields, and leaking chlorinated pipes. Past, present, and future

impacts, in conjunction with the moderate adverse impacts on hydrologic flows and water quality in

the Mariposa Grove under Alternative 1 (No Action), would result in a long­term moderate adverse

impact on hydrology and water quality in the Yosemite region.

Alternative 2: South Entrance Hub (Preferred Alternative)

Alternative 2 would remove the commercial tram operation and gift shop from the lower Grove area,

replace the existing comfort station with a smaller facility, and reduce the amount of lower Grove

area parking. Primary visitor parking would be expanded and relocated to the South Entrance,

making the South Entrance a transfer hub for visitors accessing the Grove. Numerous other

rehabilitation and restoration actions, such as improvement of hydrologic flow and removal of

impervious surfaces, project­specific prescribed fire and hazardous fuel reduction treatments, soil

decompaction, and improvement of visitor orientation and interpretation, would be components of

this alternative.

Construction­related Impacts. Construction­related impacts from Alternative 2 including the

development of the new parking lot, transfer area, and other infrastructure would be temporary.

Soil­disturbing activity during construction (i.e. excavation and grading) can lead to erosion and

sedimentation resulting from the exposure of bare soils to stormwater, which are more likely to

erode than vegetated areas that provide infiltration, retention, and dispersion. Construction activities

also involve transportation, storage, and use of hazardous materials such as fuels and solvents. These

materials could find their way to receiving waters via stormwater runoff or spills. Stream channels

and existing drainage patterns would be temporarily disrupted during culvert replacement/repair

and construction of the road new alignment and vehicular bridge in the lower Grove area. Drainage

crossings at culverts and the new vehicular bridge at the Three Sentinels near the lower Grove area

would be particularly vulnerable to degraded water quality because construction could occur in the

channel, and contaminants would have a direct path to surface water. If shallow groundwater is

encountered during construction, dewatering may be necessary.

Construction BMPs, such as good site management, erosion control (e.g., dust suppression, soil

cover, etc.), sediment controls (e.g., silt fences, gravel bag berms, etc.), and cofferdams to re­route

channels during in­stream work, would be used to minimize or avoid discharge of sediment and

other pollutants from the construction site.

Impact Significance. Local, short­term, minor, adverse impact on hydrology and water quality.

Restoration­related Impacts. Restoration of giant sequoia habitat at the Mariposa Grove under

Alternative 2 would result in a net reduction of 3.98 acres of impermeable surface area in the Grove,

with an overall net addition of developed area of 0.74 acre due to new development at the South 

Entrance. Hydrologic connectivity (surface flow and shallow groundwater) would be restored by

cleaning, repairing, and replacing dysfunctional culverts and regrading road and trail surfaces

(outsloping) where feasible. Watersheds would be restored more toward their natural configuration,

infiltration on the site would increase, and stormwater runoff would decrease, resulting in beneficial

Final Environmental Impact Statement 3­71 October 2013

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Natural Resources: Hydrology and Water Quality

Restoration of the Mariposa Grove of Giant Sequoias

impacts on surface water quality. Leaky water pipes in the upper Grove area would be repaired and

monitored. Stormwater BMPs would be implemented at the South Entrance Hub and lower Grove

shuttle area to intercept runoff from roads and parking areas, filter pollutants and sediment, and

redistribute, rather than channelize, runoff. Repair of septic systems and leach fields at the upper

Grove area and South Entrance would reduce the potential to introduce nutrients to shallow

groundwater.

Impact Significance. Local, long­term, moderate beneficial impact on water quality and Grove

hydrology.

Operation­related Impacts. Elimination of the commercial tram and fewer vehicle trips in the

Grove would reduce the amount of vehicle­related pollutants (e.g., dust, metals, petroleum­based

hydrocarbons, etc.) introduced into the Grove. Monitoring of the water supply pipeline would

reduce the likelihood that future leaks go undetected and unrepaired. Maintenance of sediment

traps and culverts would avoid discharge of pollutants from parking areas and promote improved

drainage.

New septic tanks and leach fields at the South Entrance and lower Grove area could increase use and

the subsequent potential to introduce nutrients to shallow groundwater; however, the new systems

would be superior to the current failing South Entrance and upper Grove septic systems and leach 

fields.

Impact Significance. Local, long­term, negligible, adverse and minor, beneficial impacts.

Conclusion. Construction­related impacts would include minor but temporary increased pollutants

in stormwater runoff discharged to surface water. Restoration­related impacts would improve flow

patterns and water quality. Operations­related activities would have minor beneficial impact on

water quality due to decreased vehicle use, potentially offset by negligible adverse impacts from a

new leach field at the lower Grove area and a larger leach field at the South Entrance. Overall, there

would be a long­term moderate beneficial impact on hydrology and water quality.

Cumulative Impacts. The regional past, present and reasonably foreseeable projects affecting

hydrology and water quality would be the same as those under Alternative 1 (No Action)—an overall

long­term major adverse impact on hydrology and negligible impacts on water quality in the

Yosemite region. These impacts, in conjunction with the long­term moderate beneficial impacts of

Alternative 2 on hydrology and water quality in the Mariposa Grove, from culvert installation, repair,

or replacement and wetland habitat restoration, would contribute to reversing the adverse impacts

of past actions in the region. On a regional scale, long­term moderate adverse impacts on hydrology

and negligible impacts on water quality in the Yosemite region would continue.

Alternative 3: Grizzly Giant Hub

Alternative 3 would remove the commercial tram operation and build a new bypass road, including

two new bridges, and a new larger parking lot near the Grizzly Giant, but outside of giant sequoia

habitat. This alternative would make the Grizzly Giant the primary departure point for visitors to the

Grove. The current South Entrance parking lot would remain as is, and the lower Grove parking lot

would be replaced with a small lot of only ABAAS­compliant spaces. The gift shop also would be

removed from the lower Grove area, and the lower Grove comfort stations would be replaced with a

new, smaller restroom. Numerous other rehabilitation and restoration actions, such as improvement

of hydrologic flow and universal access, project­specific prescribed fire and hazardous fuel

reduction treatments, soil decompaction, and improvement of visitor orientation and interpretation,

would be components of this alternative.

Final Environmental Impact Statement 3­72 October 2013

Chapter 3: Affected Environment and

Environmental Consequences
           

               

   

         

             

                     

                             

                     

                       

                           

                         

                           

                             

                           

                           

                         

                       

       

                       

                             

                             

           

                 

                       

                             

                               

                         

                       

                         

                         

                    

                 

                     

                       

                         

               

                               

                         

                         

                         

                               

            

         

                 

                     

                       

Natural Resources: Hydrology and Water Quality

Restoration of the Mariposa Grove of Giant Sequoias

Construction­related Impacts. Construction­related impacts from Alternative 3 would be

temporary. Soil­disturbing activity during construction (i.e. excavation and grading) can lead to

erosion and sedimentation resulting from the exposure of bare soils, which are more likely to erode

during precipitation events than vegetated areas that provide infiltration, retention, and dispersion.

Construction activities also involve transportation, storage, and use of hazardous materials such as

fuels and solvents. These eroded materials could find their way to receiving waters via stormwater

runoff or spills. Stream channels and existing drainage patterns would be temporarily disturbed

during culvert replacement/repair and construction of the two new vehicular bridges in the lower

Grove area. Leaky water pipes in the upper Grove would be excavated for repair or replacement,

which would eliminate the discharge of chlorinated water into the upper Grove wetland and to

groundwater. Stream crossings at culverts and the new bridges would be particularly vulnerable to

degraded water quality because construction could occur in the channel, and contaminants would

have a direct path to surface water. If shallow groundwater is encountered during construction,

dewatering may be necessary.

Construction BMPs, such as good site management, erosion control (e.g., dust suppression, soil

cover, etc.), sediment controls (e.g., silt fences, gravel bag berms, etc.), and cofferdams to re­route

channels during in­stream work, would be used to minimize or avoid discharge of sediment and

other pollutants from the construction site.

Impact Significance. Local, short­term, minor, adverse impact on water quality and hydrology.

Restoration­related Impacts. Restoration of the Grove under Alternative 3 would result in a net

reduction of 5.75­acres of impermeable surface area and compacted soils in the Grove, and an

overall net addition of 0.5­acre of developed area project­wide due to the new development of the

Grizzly Giant arrival area and the bypass road. Hydrologic connectivity (surface flow and shallow

groundwater) would be restored by cleaning, repairing, and replacing dysfunctional culverts and

regrading road and trail surfaces (outsloping) where feasible. Watersheds would be restored more

toward their natural configuration, infiltration on the site would increase, and stormwater runoff

would decrease, resulting in beneficial impacts on surface water quality.

Impact Significance. Regional, long­term, moderate, beneficial impact on hydrology and water

quality.

Operation­related Impacts. Fewer vehicles and removal of commercial tram trips in the upper

Grove area would reduce the amount of vehicle­related pollutants (e.g., dust, metals, petroleumbased hydrocarbons, etc.) introduced into the area. Monitoring of the water supply pipeline would

reduce the likelihood that leaks are undetected and unrepaired.

The new bridges could involve placement of footings or abutments within the channels or on the

banks that could constrict the cross­sectional area during high flow events, potentially causing local

increased velocities and corresponding scour and erosion. These potential impacts could be avoided

by appropriate design (i.e. minimal piers, longer span, maintenance of existing cross sectional shape).

Stormwater BMPs would be installed at the new parking area at Grizzly Giant Hub to intercept

runoff, filter pollutants, and redistribute flow.

Impact Significance. Regional, long­term, minor, beneficial impact.

Conclusion. Construction­related impacts would include minor but temporary increased pollutants

in stormwater runoff discharged to surface water. Restoration­related impacts would improve flow

patterns and water quality. Operation­related impacts would have minor improvements in water

Final Environmental Impact Statement 3­73 October 2013

Chapter 3: Affected Environment and

Environmental Consequences
           

               

   

         

                                 

               

                 

                               

                           

                       

                             

                       

                               

                       

                    

                             

                         

                           

                       

                   

            

             

                         

                           

                       

                           

                             

                   

                         

                           

                       

                       

                           

                           

                   

         

                     

                                 

                     

                         

                     

                           

                       

                             

                               

                           

                             

         

Natural Resources: Hydrology and Water Quality

Restoration of the Mariposa Grove of Giant Sequoias

quality due to decreased vehicle use in the upper Grove area. Overall, there would be a long­term

moderate beneficial impact on hydrology and water quality.

Cumulative Impacts. The regional past, present and reasonably foreseeable projects affecting

hydrology and water quality would be the same as those under Alternative 1 (No Action)—an overall

long­term major adverse impact on hydrology and negligible impacts on water quality in the

Yosemite region. These impacts, in conjunction with the long­term moderate beneficial impacts of

Alternative 3 on hydrology and water quality in the Mariposa Grove from culvert installation, repair,

or replacement and wetland habitat restoration, would contribute to reversing the adverse impacts

of past actions in the region. On a regional scale, long­term moderate adverse impacts on hydrology

and negligible impacts on water quality in the Yosemite region would continue.

Alternative 4: South Entrance Hub with Modified Commercial Tram Access

Alternative 4 would maintain the commercial tram but with a limited route and hours of operation

while also relocating the majority of the parking to the South Entrance, making the South Entrance

the primary departure point for visitors to the Grove. Numerous other rehabilitation and restoration

actions, such as improvement of hydrologic flow, project­specific prescribed fire and hazardous fuel

reduction treatments, soil decompaction, and improvement of visitor orientation and interpretation,

would be components of this alternative.

Construction­related Impacts. Construction­related impacts from Alternative 4 are temporary.

Soil­disturbing activity during construction (i.e. excavation and grading) can lead to erosion and

sedimentation resulting from the exposure of bare soils to stormwater, which are more likely to

erode than vegetated areas that provide infiltration, retention, and dispersion. Construction activities

also involve transportation, storage, and use of hazardous materials such as fuels and solvents. These

materials could find their way to receiving waters via stormwater runoff or spills. Stream channels

and existing drainage patterns would be temporarily disturbed during culvert replacement/repair.

Stream crossings at culverts would be particularly vulnerable to degraded water quality because

construction could occur in the channel, and contaminants would have a direct path to surface

water. If shallow groundwater is encountered during construction, dewatering may be necessary.

Construction BMPs, such as good site management, erosion control (e.g., dust suppression, soil

cover, etc.), sediment controls (e.g., street sweeping, silt fences, gravel bag berms, etc.), and

cofferdams to re­route channels during in­stream work, would be used to minimize or avoid

discharge of sediment and other pollutants from the construction site.

Impact Significance. Local, short­term, minor (with mitigation), adverse impact.

Restoration­related Impacts. Restoration of the Grove under Alternative 4 would result in a

1.85 acre removal of impermeable surface area and compacted soils in the Grove, and an overall net

addition of 2.88 acres project­wide due to new development at the South Entrance. Hydrologic

connectivity (surface flow and shallow groundwater) would be restored by cleaning, repairing, and

replacing dysfunctional culverts and regrading road and trail surfaces (outsloping) where feasible.

Watersheds would be restored to their natural configuration, infiltration on the site would increase,

and stormwater runoff would decrease, resulting in beneficial impacts on surface water quality.

Leaky water pipes in the upper Grove area would be repaired and monitored. Stormwater BMPs

would be installed at the South Entrance Hub and lower Grove shuttle area to intercept runoff from

roads and parking areas filter pollutants, and redistribute flow rather than channelize runoff. Repair

of septic systems and leach fields at the upper Grove and South Entrance would reduce the potential

to introduce nutrients to shallow groundwater.

Final Environmental Impact Statement 3­74 October 2013

Chapter 3: Affected Environment and

Environmental Consequences
           

               

   

         

         

                     

                   

                             

       

                             

                         

                     

               

                 

                     

                       

                         

                         

       

                 

                               

                           

                       

                             

                       

                               

                       

     

                           

                     

                                 

                           

                             

                                       

                             

                           

                       

                           

                       

                               

                           

                           

   

Natural Resources: Hydrology and Water Quality

Restoration of the Mariposa Grove of Giant Sequoias

Impact Significance. Regional, long­term, moderate, beneficial impact.

Operation­related Impacts. Fewer vehicle and commercial tram trips in the Grove would reduce

the amount of vehicle­related pollutants (e.g., dust, metals, petroleum­based hydrocarbons, etc.)

introduced into the Grove. Monitoring of the water supply pipeline would reduce the likelihood that

leaks are undetected and unrepaired.

New septic systems and leach fields at the South Entrance and lower Grove area could increase use

and the subsequent potential to introduce nutrients to shallow groundwater; however, the new

systems would be superior to the current failing septic systems and leach fields.

Impact Significance. Regional, long­term, minor, beneficial and minor, adverse impacts.

Conclusion. Construction­related impacts would include minor but temporary increased pollutants

in stormwater runoff discharged to surface water. Restoration­related impacts would improve flow

patterns and water quality. Operation­related impacts would have minor improvements in water

quality due to decreased vehicle use potentially offset by negligible adverse impacts on groundwater

from larger leach fields. Overall, there would be a long­term moderate beneficial impact on

hydrology and water quality.

Cumulative Impacts. The regional past, present and reasonably foreseeable projects affecting

hydrology and water quality would be the same as those under Alternative 1 (No Action)—an overall

long­term major adverse impact on hydrology and negligible impacts on water quality in the

Yosemite region. These impacts, in conjunction with the long­term moderate beneficial impacts of

Alternative 4 on hydrology and water quality in the Mariposa Grove from culvert installation, repair,

or replacement and wetland habitat restoration, would contribute to reversing the adverse impacts

of past actions in the region. On a regional scale, long­term moderate adverse impacts on hydrology

and negligible impacts on water quality in the Yosemite region would continue.

SOILS

Affected Environment

Mariposa Grove Setting

Soils along the far eastern edge of the Mariposa Grove are of the Xeric Dystrocryepts­Vitrandic

Dystrocryepts association (Natural Resources Conservation Service [NRCS] soil survey type 293),

which occur on 0 percent to 25 percent mountain slopes and summits at elevations of 6065 feet to

8960 feet (NRCS 2007). The association is 70 percent Xeric Dystrocryepts, 18 percent Vitrandic

Dystrocryepts, and 12 percent minor components. Mean annual precipitation for this soil type in the

park is 37 to 51 inches and the frost­free period is from 15 to 45 days. Soil profiles in Xeric

Dystrocryepts are largely loamy fine sands that become stony with depth. The surface area of Xeric

Dystrocryepts is covered by coarse fragments of decomposed bedrock, and there is no flooding

potential, low surface runoff, and somewhat excessive drainage. Soil profiles in Vitrandic

Dystrocryepts are largely sandy loams that become cobbly with depth. The surface area of Vitrandic

Dystrocryepts is also covered by coarse fragments, with no flooding potential, moderate surface

runoff, and somewhat excessive drainage. The types of rock in this map unit are largely granitic with 

metavolcanic and metasedimentary rock in some areas. Erosion factors range from 0.10 to 0.28

indicating low to moderate erosion potential. Frost action potential is moderate for this association

(NRCS 2007).

Final Environmental Impact Statement 3­75 October 2013

Chapter 3: Affected Environment and

Environmental Consequences
     

               

   

         

                               

                               

                               

                               

                                         

                         

                                 

                                   

                             

                             

     

                                   

             

                                 

                                 

                       

                               

                                     

                           

                             

                           

                           

                             

                             

                             

                       

                             

                             

               

                     

                 

           

           

                   

                   

               

             

         

             

       

             

                 

                               

                           

                             

                               

     

         

Natural Resources: Soils

Restoration of the Mariposa Grove of Giant Sequoias

Soils in the upper Grove are of the Clarkslodge­rock outcrop complex (NRCS soil survey type 304),

which occur on level to 30 percent slopes on metavolcanic rock at elevations of 4,885 feet to

6,755 feet throughout the park (NRCS 2007). The complex is 60 percent Clarkslodge soil, 15 percent

rock outcrop, and 25 percent minor components. Mean annual precipitation for this soil type in the

park is 35 to 45 inches and the frost­free period is from 20 to 60 days. Soil profiles of Clarkslodge are

largely decomposed plant materials near the surface, coarse sandy loam at intermediate depths, and

gravelly sandy loam at depth. The surface area of the Clarkslodge soil is covered by coarse fragments

and there is no flooding potential and medium surface runoff. The soil is well drained. The types of

rock in the upper Grove area are metavolcanic with minor amounts of granitic rock. Erosion factors

range from 0.17 to 0.37 indicating low to moderate erosion potential. Frost action potential is

moderate (NRCS 2007).

Soils in the lower Grove area and underlying the eastern portion of the Mariposa Grove Road are of

the Dystric Xeropsamments­Typic Dystoxerepts Badgerpass­Rock outcrop association (NRCS soil

survey type 261), which occur on 5 percent to 35 percent mountain slopes and in valleys at elevations

of 5,235 feet to 8,180 feet throughout the park (NRCS 2007). The association is 25 percent Dystric

Xeropsamments, 25 percent Typic Dystroxerepts, 15 percent Badgerpass soil, 15 percent Rock

outcrop, and 20 percent minor components. Mean annual precipitation for this soil type in the park

is 39 to 47 inches and the frost­free period is from 20 to 60 days. Soil profiles in Dystric

Xeropsamments are largely loamy sand. The surface area of the Dystric Xeropsamments soil is

covered by coarse fragments of decomposed bedrock and there is no flooding potential and low

surface runoff. The soil is somewhat excessively drained. Soil profiles in Typic Dystoxerepts are

largely fine loamy sand with numerous cobbles in deeper profiles. Typic Dystoxerepts is covered by

coarse fragments and some subangular gravel and cobbles. Soil profiles in Badgerpass soil are largely

gravelly loamy sand. The Badgerpass soil is covered by coarse fragments and some subangular gravel.

These two soil types have no flooding potential and moderate surface runoff. They are somewhat

excessively drained. Colluvium on mountain footslopes and toeslopes in this association extends

into mountain valleys. The majority of mountain valley areas are forested. Erosion factors range from

0.15 to 0.37 indicating low to moderate erosion potential. Frost action potential is moderate (NRCS

2007).

The presence of the relatively large number of specialstatus plant species in the Grove and the richness of the

plant community overall can be attributed in part to the

presence of metasedimentary bedrock and the

consequent presence of metasedimentary soils and

mineralized water. The soil and water of the Grove have

added nutrients and the soils retain water better than if

typical Sierra Nevada granitic bedrock was present alone.

The perennial water flow, soils derived from

decomposed metasedimentary and granitic bedrock, and

special­status plants including the giant sequoias makes

this a unique landscape.

Current issues in the Grove include soil compaction

along trails and the Mariposa Grove Road and soil

erosion due to this compaction and channelization of sheet flow. Sheet flow channelization is a result

of an inadequate drainage system along Mariposa Grove Road. Many culverts are blocked, and

overall there are not enough. Heavy visitor use has resulted in denuded vegetation and dramatic

widening of trails (figure 3­17). The paved lower Grove parking lot and the Mariposa Grove Road

Figure 3­17 – Denuded Vegetation and Soil

Compaction Along Mariposa Grove Trail

Final Environmental Impact Statement 3­76 October 2013

Chapter 3: Affected Environment and

Environmental Consequences
     

               

   

         

                   

           

     

                           

                       

                               

                             

                               

                               

                             

                                 

                                 

                         

                                   

                         

                           

                             

         

                         

                               

                             

                           

           

                               

                       

  

                         

                               

                     

   

                                   

  

                             

                           

      

                           

                         

                

Natural Resources: Soils

Restoration of the Mariposa Grove of Giant Sequoias

are impermeable surfaces covering soils, decreasing available areas for giant sequoia regeneration

and disturbing natural sheet flow and infiltration.

South Entrance Setting

Soils beneath the western portion of the Mariposa Grove Road and at the South Entrance are Typic

Halpoxerults­Ultic Haploxerifs complex (NRCS soil survey type 302), which occur on 0 percent to

30 percent mountain slopes at elevations of 4,155 feet to 5,465 feet throughout the park (NRCS

2007). The complex is 45 percent Typic Haploxerults, 41 percent Ultic Haploxeralfs, and 14 percent

Minor components. Mean annual precipitation for this complex in the park is 33 to 43 inches. The

annual frost­free period ranges from 100 to 150 days. Soil profiles of Typic Halpoxerults are largely

decomposed plant materials near the surface, loam at intermediate depths, and clay loam and sandy

clay loam at depth. The surface area of Typic Halpoxerults is covered by coarse fragments and there

is no flooding potential and moderate surface runoff. It is a well­drained soil. Soil profiles of Ultic

Haploxerifs are largely decomposed plant materials near the surface and cobbly sandy loam with 

some clay at depth. The surface area of Ultic Haploxerifs is also covered by coarse fragments. It has

no flooding potential, high surface runoff, and is somewhat excessively drained. Mountain slopes in

this map unit are mantled by hummocky, deeply weathered deposits of ancient landslide debris.

Erosion factors range from 0.20 to 0.32 indicating low to moderate erosion potential. Frost action

potential is moderate (NRCS 2007).

There are areas of impermeable surface covering soils at the South Entrance, including Wawona

Road and Mariposa Grove Road, the comfort station parking, and the small parking lot on the north 

side of the Mariposa Grove Road. These surfaces decrease available areas for plant regeneration and

also disturb natural sheet flow and infiltration, though they are outside the current distribution of the

giant sequoia at the Mariposa Grove.

Environmental Consequences

Soils analysis was based on a qualitative assessment of generalized soil types. Types of soil impacts

include those resulting from soil removal, profile mixing, compaction, erosion, contamination, and

restoration.

Beneficial impacts would protect soils from erosion or restore natural soil conditions; adverse

impacts would degrade chemical or physical properties of soils or result in the loss or temporary

removal of soils. Impact threshold definitions for soils are as follows.

Intensity Level Definitions

Negligible – Impacts on soils, such as removal of topsoil, would not occur or would be so slight as to

be immeasurable.

Minor – Impacts on soils, such as removal of topsoil, would occur but would be barely measurable

or perceptible.

Moderate – Impacts on soils would be readily apparent. Mitigation would probably be necessary to

offset adverse impacts.

Major – Impacts on soils would be readily apparent and would substantially change the soil

characteristics of the area. Extensive mitigation would probably be necessary to offset adverse

impacts, and its success could not be guaranteed.

Final Environmental Impact Statement 3­77 October 2013

Chapter 3: Affected Environment and

Environmental Consequences
     

               

   

         

        

                         

                 

                       

           

                 

                           

                                 

                           

                         

                                 

                         

                 

           

                       

                       

                         

                           

                           

                         

                                 

                     

                 

                               

                           

                               

    

                               

           

                             

                   

                 

                         

                   

                     

                               

                         

                 

                         

                                 

                       

                       

                       

       

Natural Resources: Soils

Restoration of the Mariposa Grove of Giant Sequoias

Alternative 1: No Action

Under Alternative 1 current infrastructure and park management would remain as is. No

rehabilitation and restoration actions, such as improvement of hydrologic flow, project­specific

prescribed fire and hazardous fuel reduction treatments, soil decompaction, and improvement of

visitor orientation and interpretation, would be implemented.

Operation­related Impacts. Ongoing impacts from erosion due to poor drainage and deteriorated

road conditions would continue. Ongoing compaction of soils along the Mariposa Grove Road from

the lower Grove area to the upper Grove area would also continue as maintenance vehicles and the

commercial tram consistently use the road. Routine ongoing maintenance of the road surface would

involve shoulder work and ditch maintenance and result in some soils being mixed, removed,

moved, and/or replaced. In the event of road or slope failure, soils would be disturbed and erosion

and sedimentation would occur and could affect areas downslope. Overall, under Alternative 1 there

would be local long­term moderate adverse impacts on soils.

Impact Significance. Local, long­term, moderate, and adverse.

Conclusion. Ongoing impacts from erosion due to poor drainage and deteriorated road conditions

and compaction would continue, resulting in local long­term moderate adverse impacts on soils.

Cumulative Impacts. The cumulative impacts on soils discussed in this section are based on an

analysis of past, present, and reasonably foreseeable future actions in the Yosemite region in

conjunction with the potential effects of Alternative 1 (No Action). Beneficial actions on soils would

protect areas from erosion or restore natural soils conditions; adverse actions would degrade

physical or chemical properties of soils, or result in the loss of soils. Other actions could decrease

water infiltration, with hardening of surfaces such as roads, walkways, or buildings. In the past

150 years, some activities associated with urbanization and regional population growth contributed

to the loss of soils or water infiltration in the Yosemite though much of the Yosemite region and

surrounding rural landscape is undisturbed by human impacts. The area affected by past and

possible future projects is not substantial and soil impacts would be minor when considered in a

regional context.

Current and future plans and projects in the region would have beneficial and adverse impacts on

soils (Appendix B). Comprehensive Ecological Restoration Projects, Wawona Meadow Restoration

Project, and ecological restoration elements of the Draft Merced and Tuolumne Wild and Scenic River

Comprehensive Management Plans would result in long­term beneficial impacts on soils. Activities

associated with the Fire Management Plan/Operational Fire Management Plan and U.S. Forest Service

fuels reduction projects would greatly reduce the threat of large high­severity catastrophic fires, and

reduce the potential for accelerated fire­related erosion. The Wilderness Stewardship Plan could

contribute watershed­scale protection to native landscapes and associated soils, depending on the

outcome of the final plan. These actions would have a long­term minor beneficial effect on soils.

There would be local adverse impacts on soils associated with the current South Entrance Station

Kiosks Replacement project, the Scenic Vista Management Plan, the Environmental Education

Center, and future actions associated with new development proposed in the Draft Merced River

Plan and Draft Tuolumne River Plan due to potential soil compaction, mixing, soil loss, and an overall

decrease in soil infiltration. Site­specific adverse effects on soils could be short­term (during

construction) and long­term (direct displacement of soils). These plans include mitigation measures

to prevent construction­related erosion. These actions would have a localized long­term negligible

adverse effect on soils.

Final Environmental Impact Statement 3­78 October 2013

Chapter 3: Affected Environment and

Environmental Consequences
     

               

   

         

                               

                           

                             

                       

                               

   

              

                             

                       

                     

                 

                       

                     

                             

                               

                     

                               

                       

                             

                           

                               

                           

                                 

                         

                         

                         

                      

       

                     

                                   

                               

                             

           

                             

                               

                           

                               

                             

   

                           

                               

                               

                             

         

Natural Resources: Soils

Restoration of the Mariposa Grove of Giant Sequoias

In summary, past impacts on soils in the region have been long­term, minor, and adverse. Some

present and foreseeable future actions would contribute to reversing the adverse impacts of past

actions in the region, and others would have localized negligible effects. Past, present, and future

impacts, in conjunction with the local, long­term moderate adverse impacts on soils under

Alternative 1 (No Action), would result in a long­term minor adverse impacts on soils in the

Yosemite region.

Alternative 2: South Entrance Hub (Preferred Alternative)

Alternative 2 would remove the commercial tram operation and expand parking and relocate it to

the South Entrance, making the South Entrance the primary departure point for visitors to the

Grove. Numerous other rehabilitation and restoration actions, such as improvement of hydrologic

flow, project­specific prescribed fire and hazardous fuel reduction treatments, soil decompaction,

and improvement of visitor orientation and interpretation, would be components of this alternative.

Construction­related Impacts. During excavation and grading for the new parking lot at the South 

Entrance and optional new bridge near the Three Sentinels, soils would be mixed, moved, and

replaced, affecting the area’s soil profiles, with the greater degree of impact occurring in the areas not

previously disturbed by construction. In the limited areas previously disturbed by construction,

these impacts would also occur, but would result in negligible to minor additional impacts on soils,

given the compaction and disturbance that has already taken place. Installation and/or replacement

of septic systems and leach fields at the South Entrance, lower Grove area, and upper Grove area

would result in additional soil disturbance. Possible construction of a roundabout at the Wawona

Road – Mariposa Grove Road intersection would result in disturbance of soils and covering of some

by an impervious surface. Clearing of vegetation and grading would occur along the existing

Washburn Road and in an undisturbed area south of the Mariposa Grove Road and east of the picnic

area during construction of the proposed South Entrance to lower Grove area pedestrian trail.

Moving, covering, trampling, and compaction of soils by equipment and workers within the

construction work zone would also occur. Local soil compaction would temporarily decrease soil

permeability, change soil moisture content, and lessen its water storage capacity.

Impact Significance. Local, short­term, moderate, and adverse.

Restoration­related Impacts. Culverts slated for cleaning, headwall installation, or repair would

result in some impacts on soils. There would also be excavation of soils at culvert ends to ensure

clear passage for water flow during rain or snowmelt. The installation of new culverts and replaced

culverts would also result in limited soil excavation. These actions would constitute a minor to

moderate local adverse impact on soils.

Because of planned decompaction during restoration in areas of the upper Grove area (loop and

along margin of road) and lower Grove area (where current road exists near parking lot) where

exposed soils remain, decompaction in these areas would constitute a negligible to minor, short­term

adverse impact on soils. Giant sequoia root systems are typically shallow and extensive. As a result,

decompaction would occur only at the very surface and park managers would monitor for exposed

root systems.

Upon successful seeding and/or replanting, there would also be a long­term minor to moderate

beneficial impact as the growth of plants and their return of nutrients and water holding capacity to

soils in restored areas resulted in less erosion and more stable roadsides. There would be additional

beneficial impacts from the use of native plants in restoration and from decreasing the erosion

potential of alongside the road.

Final Environmental Impact Statement 3­79 October 2013

Chapter 3: Affected Environment and

Environmental Consequences
     

               

   

         

         

                   

                         

                             

                             

                                   

                       

                           

                       

         

                       

                           

             

                   

                             

                             

                             

                           

                           

         

          

                             

                                 

                               

                     

                 

                       

                   

                             

                             

                       

                           

                         

               

                         

                                 

                   

                   

                           

                               

             

             

Natural Resources: Soils

Restoration of the Mariposa Grove of Giant Sequoias

Impact Significance. Local, long­term, moderate, and beneficial.

Operation­related Impacts. Impacts from erosion due to poor drainage and deteriorated road

conditions would discontinue. Less channelization of water would result in better infiltration and

reduced erosion of soils. Ongoing compaction of soils along the Mariposa Grove Road from the

lower Grove area to the upper Grove area would continue as maintenance vehicles periodically use

the road but would be confined to a narrower road and would not include the upper Grove loop.

Routine ongoing maintenance of the road surface would involve shoulder work and ditch 

maintenance and result in some soils being mixed, removed, moved, and/or replaced. Overall, under

Alternative 2 there would be local long­term moderate beneficial impacts on soils.

Impact Significance. Local, long­term, moderate, and beneficial.

Conclusion. Current impacts from erosion due to poor drainage and deteriorated road conditions

and compaction of soils would be alleviated but somewhat offset by new infrastructure outside the

Grove, resulting in a long­term moderate beneficial impact.

Cumulative Impacts. The regional past, present, and reasonably foreseeable projects affecting soils

would be the same as those under Alternative 1 (No Action)—an overall long­term minor adverse

impact on soils in the Yosemite region. There would be a long­term moderate beneficial impact

under Alternative 2 due to decreased erosion and soil compaction in the Mariposa Grove, which is

partially offset by new construction at the South Entrance. Past, present, and future projects, in

conjunction with the impacts of Alternative 2 would result in long­term minor adverse impacts on

soils in the Yosemite region.

Alternative 3: Grizzly Giant Hub

Alternative 3 would remove the commercial tram operation and build a new bypass road, including

two new bridges, and a new larger parking lot near the Grizzly Giant, but outside giant sequoia

habitat. This alternative would make the Grizzly Giant the primary departure point for visitors to the

Grove. Numerous other rehabilitation and restoration actions, such as improvement of hydrologic

flow, project­specific prescribed fire and hazardous fuel reduction treatments, soil decompaction,

and improvement of visitor orientation and interpretation, would be components of this alternative.

Construction­related Impacts. During excavation and grading for construction of the new access

road, associated bridges, and parking lot, soils would be mixed, moved, and replaced, affecting the

area’s soil profiles, with the greater degree of impact occurring in the limited areas not previously

disturbed by construction. In limited areas previously disturbed by construction, these impacts

would also occur, but would result in negligible to minor additional impacts on soils. Installation

and/or replacement of septic systems and leach fields at the South Entrance, lower Grove area, and

upper Grove area would result in additional soil disturbance.

Moving, covering, trampling, and compaction of soils by equipment and workers within the

construction work zone would also occur; however, a majority of soils that would be affected in the

project corridor have been previously disturbed by road­related development activities (e.g.,

maintenance and construction). Local soil compaction would temporarily decrease soil permeability,

change soil moisture content, and lessen its water storage capacity. Because the Mariposa Grove

Road would be converted to a hardened surface and its width decreased, there would be a decrease

in surface area covered by impermeable materials.

Impact Significance. Local, long­ and short­term, moderate and adverse.

Final Environmental Impact Statement 3­80 October 2013

Chapter 3: Affected Environment and

Environmental Consequences
     

               

   

         

                 

                                   

                               

                             

           

                             

                               

                         

                               

                             

   

                           

                               

                               

                             

       

         

                 

                               

                                   

                               

                               

                               

                           

               

             

                       

                         

                               

                   

                             

                             

                             

                             

                             

                   

                    

                             

                         

                           

                       

                       

        

Natural Resources: Soils

Restoration of the Mariposa Grove of Giant Sequoias

Restoration­related Impacts. Culverts slated for cleaning, headwall installation, or repair would

result in some impacts on soils. There would also be excavation of soils at culvert ends to ensure

clear passage for water flow during rain or snowmelt. The installation of new culverts and replaced

culverts would also result in limited soil excavation. These actions would constitute a minor to

moderate local adverse impact on soils.

Because of planned decompaction during restoration in areas of the upper Grove (loop and along

margin of road) and lower Grove area (where current road exists near parking lot) where exposed

soils remain, decompaction in these areas would constitute a negligible to minor, short­term

beneficial impact on soils. Giant sequoia root systems are typically shallow and extensive. As a result,

decompaction would occur only at the very surface and park managers would monitor for exposed

root systems.

Upon successful seeding and/or replanting, there would also be a long­term minor to moderate

beneficial impact as the growth of plants and their return of nutrients and water holding capacity to

soils in restored areas resulted in less erosion and more stable roadsides. There would be additional

beneficial impacts from the use of native plants in restoration and from decreasing the erosion

potential of alongside the road.

Impact Significance. Local, long­term, moderate, and beneficial.

Operation­related Impacts. Ongoing impacts from erosion due to poor drainage and deteriorated

road conditions would be reduced in areas in the lower Grove area where impervious surfaces would

be removed. The road in the lower Grove area and fill materials would be removed and soils would

be restored. Ongoing compaction of soils along the Mariposa Grove Road from the lower Grove area

to the upper Grove area would continue as maintenance vehicles periodically use the road but would

be confined to a narrower road and would not include the upper Grove loop. Routine ongoing

maintenance of the road surface would involve shoulder work and ditch maintenance and result in

some soils being mixed, removed, moved, and/or replaced.

Impact Significance. Local, long­term, minor to moderate, and beneficial.

Conclusion. Current impacts from erosion due to poor drainage and deteriorated road conditions

and compaction of soils would be alleviated but partially offset by disturbance of new infrastructure,

resulting in a long­term minor beneficial impact, due to the impacts of road construction on soils.

Cumulative Impacts. The regional past, present, and reasonably foreseeable projects affecting soils

would be the same as those under Alternative 1 (No Action)—an overall long­term minor adverse

impact on soils in the Yosemite region. There would be a long­term moderate beneficial impact

under Alternative 3 due to decreased erosion and soil compaction and increased soil infiltration in

the Mariposa Grove, which is partially offset by new road construction to the Grizzly Giant hub.

Past, present, and future projects, in conjunction with the impacts of Alternative 3 would result in

long­term minor adverse impacts on soils in the Yosemite region.

Alternative 4: South Entrance Hub with Modified Commercial Tram Access

Alternative 4 would maintain the commercial tram but with a limited route and hours of operation

while also relocating the majority of the parking to the South Entrance, making the South Entrance

the primary departure point for visitors to the Grove. Numerous other rehabilitation and restoration

actions, such as improvement of hydrologic flow, prescribed fire and hazardous fuel reduction

treatments, soil decompaction, and improvement of visitor orientation and interpretation, would be

components of this alternative.

Final Environmental Impact Statement 3­81 October 2013

Chapter 3: Affected Environment and

Environmental Consequences
     

               

   

         

                   

                             

                         

                               

                       

                             

                           

                               

    

                         

                                 

                   

                   

                         

                               

                           

                           

                         

                               

                             

                               

                      

       

                 

                                   

                               

                             

           

                           

                               

                               

                             

                         

         

                 

                           

                                 

                           

                         

                                 

             

             

Natural Resources: Soils

Restoration of the Mariposa Grove of Giant Sequoias

Construction­related Impacts. During excavation and grading, soils would be mixed, moved, and

replaced, affecting the area’s soil profiles, with the greater degree of impact occurring in the limited

areas not previously disturbed by construction. In areas previously disturbed by construction, these

impacts would also occur, but would result in negligible to minor additional impacts on soils, given

the compaction and disturbance that has already taken place. Installation and/or replacement of

septic systems and leach fields at the South Entrance, lower Grove area, and upper Grove area would

result in additional soil disturbance. Construction of the modified T at the Wawona Road –

Mariposa Grove Road intersection would result in disturbance of soils and covering of some by an

impervious surface.

Moving, covering, trampling, and compaction of soils by equipment and workers within the

construction work zone would also occur; however, a majority of soils that would be affected in the

project corridor have been previously disturbed by road­related development activities (e.g.,

maintenance and construction). Local soil compaction would temporarily decrease soil permeability,

change soil moisture content, and lessen its water storage capacity. Because of planned

decompaction during restoration in areas of the upper Grove (loop and along margin of road) and

lower Grove area (where current road exists near parking lot) where exposed soils remain,

decompaction in these areas would constitute a negligible to minor, short­term adverse impact on

soils. Giant sequoia root systems are typically shallow and extensive. As a result, decompaction

would occur only at the very surface and park managers would monitor for exposed root systems.

Although the lower Grove parking area would decrease in size and the Mariposa Grove Road would

remain the same width, there would be an increase in surface area covered by impermeable materials

due to the construction of the parking lot at the South Entrance.

Impact Significance. Local, short­term, moderate, and adverse.

Restoration­related Impacts. Culverts slated for cleaning, headwall installation, or repair would

result in some impacts on soils. There would also be excavation of soils at culvert ends to ensure

clear passage for water flow during rain or snowmelt. The installation of new culverts and replaced

culverts would also result in limited soil excavation. These actions would constitute a minor to

moderate local adverse impact on soils.

Upon successful seeding and/or replanting, there would also be a long­term minor to moderate

beneficial impact as the growth of plants and their return of nutrients and water holding capacity to

soils in restored areas resulted in less erosion and more stable roadsides. There would be additional

beneficial impacts from the use of native plants in restoration and from decreasing the erosion

potential of cut­slopes alongside the road by removing some overhanging vegetation and loose

rocks.

Impact Significance. Local, long­term, moderate, and beneficial.

Operation­related Impacts. Ongoing impacts from erosion due to poor drainage and deteriorated

road conditions would continue. Ongoing compaction of soils along the Mariposa Grove Road from

the lower Grove area to the upper Grove area would also continue as maintenance vehicles and the

commercial tram consistently use the road. Routine ongoing maintenance of the road surface would

involve shoulder work and ditch maintenance and result in some soils being mixed, removed,

moved, and/or replaced. In the event of road or slope failure, soils would be disturbed and erosion

and sedimentation would occur and could affect areas downslope.

Impact Significance. Local, long­term, minor to moderate, and beneficial.

Final Environmental Impact Statement 3­82 October 2013

Chapter 3: Affected Environment and

Environmental Consequences
     

               

   

         

                       

                         

                         

                 

                             

                             

                             

                           

                           

         

       

                                 

                             

                             

                       

                         

           

                         

                               

                           

                         

                               

                             

                           

                           

                             

                        

         

   

                 

                           

                               

                               

                         

                      

Natural Resources: Soils

Restoration of the Mariposa Grove of Giant Sequoias

Conclusion. Current impacts from erosion due to poor drainage and deteriorated road conditions

and compaction of soils would be alleviated but partially offset by disturbance of new infrastructure

and continued commercial tram use, resulting in a long­term minor to moderate beneficial impact.

Cumulative Impacts. The regional past, present, and reasonably foreseeable projects affecting

vegetation would be the same as those under Alternative 1 (No Action)—an overall long­term minor

adverse impact on soils in the Yosemite region. There would be a long­term moderate beneficial

impact under Alternative 4 due to decreased erosion and soil compaction in the Mariposa Grove,

which is slightly offset by new construction at the South Entrance. Past, present, and future projects,

in conjunction with the impacts of Alternative 4 would result in long­term minor adverse impacts on

soils in the Yosemite region.

AIR QUALITY AND CLIMATE CHANGE

Affected Environment

Yosemite National Park is classified as a mandatory Class I area under the federal Clean Air Act

(42 USC 7401 et seq.). This air quality classification is aimed at protecting parks and designated

wilderness areas from air quality degradation. The federal Clean Air Act gives federal land managers

the responsibility for protecting air quality and related values from adverse pollution impacts,

including effects on visibility, plants, animals, soils, water quality, visitor health, and cultural

resources and historic structures and objects.

The United States Environmental Protection Agency (EPA) and the California Air Resources Board

designate whether or not counties in California are in attainment of federal and state ambient air

quality standards for criteria pollutants. As table 3­6 shows, the criteria pollutants include ozone,

carbon monoxide, nitrogen dioxide, sulfur dioxide, particulate matter greater than 10 microns and

greater than 2.5 microns in diameter (PM10 and PM2.5), and lead. The project is within Mariposa

County, which is part of the Mountain Counties Air Basin. Air quality and emission sources in

Mariposa County are regulated by the Mariposa County Air Pollution Control District. The portion

of Mariposa County within Yosemite National Park is designated nonattainment for the national and

state ozone standards and for the state PM10 standards. Mariposa County is designated as either

attainment or unclassified for the remaining national and state air quality standards.

Table 3­6 – Mariposa County Attainment/Nonattainment Designations

Criteria Pollutant National State

Ozone Nonattainment Nonattainment

PM10 Unclassified Nonattainment

PM2.5 Attainment/Unclassified Unclassified

Carbon Monoxide Attainment/Unclassified Unclassified

Nitrogen Dioxide Attainment/Unclassified Attainment

Sulfur Dioxide Unclassified Attainment

Lead No Designation Attainment

Source: U.S. Environmental Protection Agency, 2011; California Air Resources Board, 2011

National nonattainment areas are subject to conformity under Section 176 of the federal Clean Air

Act as applicable. The conformity rule prevents federal funding of a project unless it can be

demonstrated that the project would not cause or contribute to violations of the federal ambient air

quality standards. Since Mariposa County is nonattainment for the federal ozone standard, a

conformity evaluation for the Mariposa Grove Ecological Restoration Project is required.

Final Environmental Impact Statement 3­83 October 2013

Chapter 3: Affected Environment and

Environmental Consequences
             

               

   

         

                       

                         

                     

                       

                             

                         

                         

                                 

                         

                     

                           

   

                               

                       

                         

                   

                           

                             

   

           

                             

                             

                         

                           

                         

                     

                             

                     

                                 

                   

                             

                       

         

Natural Resources: Air Quality and Climate Change
 

Restoration of the Mariposa Grove of Giant Sequoias
 

Criteria pollutant emissions that affect Yosemite National Park are caused by sources both within

and outside of the park. Emissions from various sources within the San Joaquin Valley—mobile

sources, power plants, food processors, and industrial facilities—are transported to the park.

Emissions from these sources include PM10, sulfur dioxide, volatile organic compounds, carbon

monoxide, and nitrogen dioxide. Natural and prescribed fires that occur in the Sierra during dry

summer months occasionally impair Yosemite’s air quality as well, though the impacts are usually

local. Large wild fires outside Yosemite, such as in Southern California, commonly impact Yosemite,

too, and often affect the entire park. Westerly winds blow pollution into Yosemite on a regular basis,

especially during the summer. Yosemite National Park, in cooperation with state and other federal

agencies, monitors the effects caused by air pollution with a comprehensive, science­based air

resources program. This program targets major air pollutants and the effects on Yosemite’s visitors

and ecology.

Air quality in the park is also affected by emission sources within Yosemite National Park. Air

pollution sources include motor vehicles and stationary sources, such as furnaces, boilers, wood

stoves, campfires, generators, barbecues, and prescribed fires. Most of the stationary sources are

associated with park operations (NPS and concessioner). Campfires and associated emissions,

however, are typically generated by visitors. Private, NPS, and concessioner vehicles and tour buses

constitute the largest sources of mobile source emissions in Yosemite Valley and in the Mariposa

Grove area.

Mariposa Grove and South Entrance Settings

Air quality in the Mariposa Grove and at the South Entrance is generally good, with few major

emission sources. On­road motor vehicles represent the primary source of emissions in the area. The

closest air quality monitoring station is at Turtleback Dome, which is approximately 16 miles north 

northwest of the Mariposa Grove at approximately 5,300 feet. At the Turtleback Dome station,

ozone monitoring data recorded between 2006 and 2010 exceeded both the state and federal ozone

standards (table 3­7). The Yosemite Village Visitor Center monitoring station is approximately

18 miles north­northeast of the Mariposa Grove. At the Yosemite Village Visitor Center, PM10 data

recorded exceeded the California PM10 standard, but not the national standard.

There are few people with sensitivity to air quality in the immediate vicinity of the Mariposa Grove

or the South Entrance. Although the Mariposa Grove may draw both adolescent and elderly

visitors— population groups sensitive to air quality— their exposure to the ambient air quality in

Yosemite National Park is temporary, and consequently visitors are not considered “sensitive

receptors” to local air quality.

Final Environmental Impact Statement 3­84 October 2013

Chapter 3: Affected Environment and

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Natural Resources: Air Quality and Climate Change

Restoration of the Mariposa Grove of Giant Sequoias

Table 3­7 – Air Quality Monitoring Data for Yosemite National Park

Pollutant

National 

Standard

State

Standard

Monitoring Data by Year

2006 2007 2008 2009 2010

Ozone Monitoring Data*

Station: Yosemite National Park – Turtleback Dome

Highest 1­hour average, ppm NA 0.09 0.100 0.100 0.108 0.096 0.091

Days over state standard 4 3 11 1 0

Highest 8­hour average, ppm 0.08 0.07 0.084 0.09 0.102 0.086 0.085

Days over national standard 20 25 33 8 5

Particulate Matter (PM10) Monitoring Data

Station: Yosemite Village – Visitor Center

Highest 24­hour average μg/m3

(national/state)** 150 50 104//97 127/116 136/118 90/82 81/74

Days over state standard

(measured)*** 3 1 2 3 2

Days over national standard

(measured)*** 0 0 0 0 0

*”Days over standard” refers to the number of days in a given year during which the ozone concentration exceeded

the hourly state or national standard for at least one hour.

** State and national statistics may differ due to variations in sampling equipment, locations, references, and

equivalent methods.

***PM10 is usually measured every sixth day (rather than continuously as is the case for other pollutants). Measured

days are based on the days that measurement was greater than the standard.

NA = not applicable

ppm = parts per million by volume

μg/m3 = micrograms per cubic meter

Source: The monitoring stations are operated by the National Park Service. Monitoring results are reported on the

California Air Resources Board’s iADAM air quality data statistics web pages (California Air Resources Board, 2012).

Climate Change

In addition to criteria pollutant emissions, greenhouse gas emissions threaten the natural identity

and unique resources of national parks such as Yosemite through contributions to climate change.

Accordingly, Yosemite National Park participates in the Climate Friendly Parks Program

implemented by EPA and NPS, and has been designated a “Climate Friendly Park.” To obtain this

designation, Yosemite conducted a baseline greenhouse gas emissions inventory, developed a

Climate Action Plan, and committed to educating park staff, visitors, and community members about

climate change (Yosemite National Park 2006).

Global climate change is already affecting ecosystems in the Sierra Nevada. These changes include

shifted plant growth cycles and changes in stream flow peaks due to snowmelt. Global warming is

likely to shift habitats to higher elevations. Increasing temperatures and more frequent drought will

likely affect fire regimes and pest/disease outbreaks (Davey et al. 2007).

The environmental factors most likely to influence giant sequoia ecology as a result of climate change

include decreases in snow­dominated precipitation, decreases in overall precipitation (including a

longer summer drought period), and climate change interactions with other stressors (such as

insects, pathogens, and air pollution). All phases of giant sequoia growth will likely be influenced by

climate change, but effects on the regeneration phase—dispersal, germination, and early

establishment—have the greatest potential to be detectable in the near term (York 2011).

Final Environmental Impact Statement 3­85 October 2013

Chapter 3: Affected Environment and

Environmental Consequences
             

               

   

         

   

                                 

                                 

    

                                 

                         

                     

                               

                           

        

                               

                       

               

        

                   

                   

                           

                           

                               

                         

                 

                           

                           

                     

                         

                             

                               

              

                         

                           

                               

                           

                           

                       

                           

                             

                                 

                 

Natural Resources: Air Quality and Climate Change
 

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Environmental Consequences

Intensity Level Definitions

Beneficial – Air emissions would decrease as a result of the alternative relative to baseline (no action)

conditions.

Negligible – Air emissions would not increase as a result of the alternative relative to baseline (no

action) conditions.

Minor – Air emissions would increase slightly as a result of the alternative relative to baseline (no

action) conditions, but would not be noticeable to sensitive individuals. Mitigation measures would

likely not be necessary due to the low level of emissions.

Moderate – Air emissions would increase moderately as a result of the alternative relative to baseline

(no action) conditions, and would be noticeable to sensitive individuals. Mitigation would be needed

to offset adverse effects.

Major – Air emissions would increase substantially as a result of the alternative relative to baseline

(no action) conditions, and would potentially affect the health of sensitive individuals. Extensive

mitigation would be necessary to offset adverse effects.

Alternative 1: No Action

Under Alternative 1, current infrastructure would be maintained and current park/concessioner

operations, maintenance, and management practices would continue. Several existing sources of

criteria pollutant and greenhouse gas emissions would continue to operate. These include the gift

shop diesel­powered generator in the lower Grove area, the tour tram, commercial tram traffic on

unpaved sections of the roads, idling buses/circling visitor vehicles searching for a parking spot in the

lower Grove area, and the propane­powered generator at the Wawona Point communications shed.

Operations­related Impacts. Under Alternative 1, air and greenhouse gas emissions would

continue to be generated by on­going activities at the Mariposa Grove. Existing emission sources

consist of mobile and stationary sources. Mobile sources include visitor vehicles, tour buses, shuttle

buses (from Wawona and the South Entrance), employee vehicles (concessioner and park

employees), and commercial trams. Two stationary sources, a diesel generator that provides power

to the lower Grove gift shop, and a propane­powered generator at the communications structure at

Wawona Point, would be retained. The existing vault toilets in the lower Grove area would continue

to be a source of nuisance odors.

Continued operations at the Mariposa Grove would generate vehicle emissions from these mobile

and stationary sources. Although these emissions contribute to the overall air emissions in the park,

they represent a small portion of the park’s total daily emissions. Also, the nuisance odors associated

with vault toilets would continue to affect visitors. The vehicle and stationary source emissions have

the potential to affect sensitive individuals visiting the Mariposa Grove. Over time, vehicle emissions

are expected to decrease as newer, lower­emitting commercial trams, buses, and passenger vehicles

replace older, higher­emitting vehicles. This reduction would be offset somewhat by increases in the

number of visitors. In addition, visitor exposure to pollutants from emission sources in the Mariposa

Grove would be limited to the time spent visiting the Grove. These two factors would minimize the

impacts on sensitive individuals who visit the Mariposa Grove.

Final Environmental Impact Statement 3­86 October 2013

Chapter 3: Affected Environment and

Environmental Consequences
             

               

   

         

                           

                             

                 

         

                     

                       

                           

                             

                         

          

                         

                       

                         

                           

                       

                             

                                 

                         

                         

                         

                           

                               

       

                           

                         

                             

               

                               

                   

                         

                     

                             

                           

                       

                  

                         

                     

                               

                           

                       

                         

       

                               

                       

Natural Resources: Air Quality and Climate Change

Restoration of the Mariposa Grove of Giant Sequoias

Nuisance odors associated with vault toilet operations would continue to affect visitors in the lower

Grove area, and could become increasingly noticeable as the number of Grove visitors continues to

increase. This represents a moderate adverse impact on sensitive individuals.

Impact Significance. Site­specific, long­term, moderate, adverse impact.

Conclusion. No project construction or Grove restoration­related impacts would occur. The impact

of volatile organic compounds, particulate matter, and greenhouse gas emissions related to

continued Grove operations, maintenance, and visitor access on regional air quality and on visitors

to Yosemite National Park and the Mariposa Grove would be negligible. Nuisance odors from vault

toilets, however, would continue to worsen as visitation increases and would have a moderately

adverse impact on sensitive individuals.

Cumulative Impacts. Cumulative impacts on air quality are based on analysis of past, present, and

reasonably foreseeable future actions in the Yosemite region in conjunction with the potential effects

of each alternative. Since 1950, the population of California has tripled, and the number of vehiclemiles­traveled 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 vehicle

sources in upwind areas, especially within the San Joaquin Valley. Since the 1970s, emissions sources

within the park, as well as California as a whole, have been subject to local stationary­source controls

and state and federal mobile­source 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, which has helped to offset air quality problems resulting

from population growth, increased industrial activity, and the greater number of vehicles in use.

These past impacts have resulted in a long­term, moderate adverse impact on air quality and climate

change in the region.

Present and future regional, state, and federal activities would have beneficial and adverse impacts

on air quality and climate change. Regional, state, and federal regulatory programs tightening

emissions standards have been adopted and will likely produce beneficial impacts on air quality and

climate change (through reduced greenhouse gas emissions). Although cumulative growth in the

Central Valley region will tend to adversely affect air quality within the park including the Mariposa

Grove, implementation of ongoing state and federal mobile­source control programs would

ameliorate this effect to a degree. The potential effects of additional increases in California’s

population, particularly in the Central Valley, additional state and federal regulations of greenhouse

gases (GHGs) and other air pollutants such as particulate matter, are difficult to predict, but would

likely have offsetting adverse and beneficial effects. State and federal efforts to address climate

change including regulations requiring greenhouse gas (GHG) emissions reductions are by nature

global and cumulative, but would have long­term beneficial effects.

The Yosemite Area Regional Transportation System (YARTS) is a multi­agency effort to provide

public transportation options, reduce reliance on automobiles, and improve regional air quality. Ongoing operation of the YARTS is expected to result in long­term, beneficial impacts on air quality

throughout the region. By providing expanded levels of service (more frequent runs and additional

destinations) during peak visitation and reducing service during the quieter months, YARTS

maximizes its potential to reduce use of personal vehicles, while minimizing unnecessary emissions

associated with its own operation.

At a park level, the NPS is developing the Draft Merced River Wild and Scenic River Comprehensive

Management Plan. The plan proposes an expansion of transit regional options, which would have

Final Environmental Impact Statement 3­87 October 2013

Chapter 3: Affected Environment and

Environmental Consequences
             

               

   

         

                       

                     

               

                           

                                

                       

                 

               

                 

                       

                         

                

                               

                         

                             

                         

                               

   

                             

                             

                           

                           

                     

              

                         

                             

                               

                                 

                                   

                           

                           

                             

                         

                         

                       

                       

             

                         

                         

                           

                       

                                 

                     

          

Natural Resources: Air Quality and Climate Change
 

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beneficial effects on air quality by providing visitors with public transportation to the South 

Entrance, the busiest entrance in the park, and into the park.
 

The Fire Management Plan/Operational Fire Management Plan would have short­term but moderate
 

adverse impacts on air quality. Other reasonably foreseeable future NPS projects are not anticipated
 

to have a net adverse or beneficial effect on air quality except for short­term, localized impacts.
 

Federal agencies and installations are required to comply with federal climate change policy
 

including Executive Order 13423, Strengthening Federal Environmental, Energy, and Transportation
 

Management, which instructs federal agencies to conduct their environmental, transportation, and
 

energy­related activities in an environmentally, economically, and fiscally sound, integrated,
 

continuously improving, efficient, and sustainable manner. Executive Order (EO) 13423 also directs
 

federal agencies to implement sustainable practices for energy efficiency and reductions in GHG
 

emissions, and for the use of renewable energy.
 

In summary, past impacts on the air quality in the Mariposa region have been long­term, adverse,
 

and moderate. Present and foreseeable future actions, would have negligible cumulative effects on
 

air quality. Alternative 1 (No Action) would have long­term negligible impacts on air quality. Past,
 

present, and future impacts, in conjunction with the long­term negligible impacts on air quality
 

under Alternative 1 (No Action), would result in long­term moderate impacts on air quality in the
 

Yosemite region.
 

In terms of climate change, particularly because the effects from greenhouse gas emissions are global
 

in nature and cumulative on world­wide basis, individual sources of greenhouse gases related to past,
 

present, and future plans and projects are not large enough to have an appreciable effect.
 

Alternatives 1­4, in conjunction with past, present, and future actions and projects in the region,
 

would have a negligible, long­term adverse cumulative effect on climate change.
 

Alternative 2: South Entrance Hub (Preferred Alternative)

Under Alternative 2, the in­Grove commercial tram operation would be discontinued; the in­Grove

access road pavement would be replaced with a hardened surface; the gift shop would be removed;

and the capacity of the lower Grove parking lot would be reduced, and restricted to off­season

visitor use. The lower Grove comfort station would be remodeled as a smaller facility, and the water

tank and chlorination unit would be relocated to a site down gradient from the museum in the upper

Grove. A new, 295­space parking area and visitor facilities would be built at the South Entrance,

making the South Entrance the primary source of visitor information and the main departure point

(“hub”) for visitors to the Grove. During peak and shoulder seasons, shuttle service would replace

access to the Grove via privately owned vehicles (POVs). Numerous other rehabilitation and

restoration actions would be components of this alternative, such as rehabilitation of Wawona Point,

giant sequoia habitat restoration; improvement of hydrologic flows in the Grove; updated prescribed

fire treatment; soil decompaction; and improvement of visitor orientation, way finding, and

interpretation.

Construction­related Impacts. Construction of parking areas and associated support infrastructure

at the South Entrance would generate short­term air and greenhouse gas emissions that include

exhaust from construction vehicles, heavy equipment, and gas­powered hand tools (e.g., chain saws);

and generation of fugitive dust during ground disturbance New parking lot construction at the South 

Entrance also would generate reactive organic compound (ROG) emissions from asphalt off­gassing

as it cools and hardens. Parking lot striping and painting or staining of new or refurbished structures

would also generate short­term ROG emissions associated with evaporation of volatile organic

compounds in paints and solvents.

Final Environmental Impact Statement 3­88 October 2013

Chapter 3: Affected Environment and

Environmental Consequences
             

               

   

         

                           

                             

                   

                         

         

                     

                         

                             

                       

                             

                  

                       

                         

                         

                     

                             

                               

                   

                    

                           

                             

                           

                             

              

       

                 

                         

                   

                           

                                 

                      

        

                     

                             

                           

                               

                         

                         

                       

                  

                                 

                                 

                       

Natural Resources: Air Quality and Climate Change
 

Restoration of the Mariposa Grove of Giant Sequoias
 

Lower Grove area modifications, including removal of the parking lot, gift shop, commercial tram

staging, fueling, comfort station, and ticketing areas, and repaving of a smaller lower Grove parking

area would also generate short­term, site­specific emissions from construction activities. These

emissions would include exhaust from construction vehicles and heavy equipment, and dust from

equipment operating on exposed earth.

Construction activities associated with implementation of Alternative 2 restoration of the Mariposa

Grove and development of a new South Entrance transit hub would generate criteria pollutants,

toxic air contaminants, and greenhouse gases. PM10 and PM2.5 would occur as fugitive dust from

disturbed soil and demolition activities and from exhaust of heavy­duty and hand­held equipment.

Particulate emissions would vary during the construction period depending on the level and type of

activity, silt content of the soil, and weather conditions.

Emissions generated from construction and removal activities would include tailpipe emissions from

heavy­duty equipment, worker commute trips, and truck trips to haul debris to appropriate disposal

or reuse sites, and to supply the site with construction materials. Both mobile and stationary

equipment would generate emissions of criteria pollutants, (toxic air contaminants, and greenhouse

gases from the use of diesel­ and gasoline­ powered equipment. Toxic air contaminants are less

pervasive in the atmosphere than criteria air pollutants, but they are linked to short­term (acute) and

long­term (chronic and/or carcinogenic) adverse human health effects. Neither toxic air

contaminants nor greenhouse gases have corresponding ambient air quality standards.

The temporary duration of the construction period, expected to be implemented in phases over

several years, would limit the potential for tailpipe emissions of criteria pollutants and toxic air

contaminants to adversely affect local air quality. In addition, visitors would be exposed to

construction emissions for the limited period of time associated with their visit. Visitor use of and

access to construction zones would be restricted.

Impact Significance. Short­term, site­specific, minor, adverse impact.

Restoration­related Impacts. Short­term increases in criteria pollutant, toxic air contaminants and

greenhouse gas emissions would result from restoration activities similar to those described above

for construction­related impacts. Restoration­related air emissions would be generated by activities

requiring the use of off­road construction equipment (typically powered by gasoline or diesel fuel),

by worker trips, and by hauling of materials to and from the site. Restoration activities may also

generate dust that could be a nuisance to workers or visitors.

Impact Significance. Short­term, site­specific, minor, adverse impact.

Operations­related Impacts. Moving the hub to the South Entrance and removing the trams would

improve long term air quality within Mariposa Grove. Under Alternative 2, POV use would be

reduced substantially between the South Entrance Hub and the lower Grove area as POV access to

the grove during peak and shoulder seasons would be replaced by shuttle service from a new South 

Entrance Hub. Consequently, exhaust and dust emissions from visitor vehicles traveling on the

South Entrance to lower Grove road segment would be replaced by shuttle bus emissions, which 

would substantially reduce vehicle emissions along this road segment. This would reduce the

exposure of Grove visitors to exhaust and dust emissions.

The generator used to power the lower Grove gift shop would be moved to the South Entrance Hub

area where electrical power would be the primary power source and the generator used as back up.

This switch would eliminate the air and greenhouse gas emissions produced by the generator.

Final Environmental Impact Statement 3­89 October 2013

Chapter 3: Affected Environment and

Environmental Consequences
             

               

   

         

                           

                           

                                 

                           

                                       

                       

         

                           

                           

                       

        

                   

                     

                               

                           

                         

                           

                       

                  

                         

                           

                         

                             

                               

                     

                         

                              

                         

             

                         

                                 

                         

                             

                

         

                                 

                           

                                 

                       

                               

                                 

                           

                     

                       

             

Natural Resources: Air Quality and Climate Change

Restoration of the Mariposa Grove of Giant Sequoias

However, there would still be indirect air and greenhouse gas emissions associated with the electrical

generation used to supply the gift shop, though such emissions would be produced outside of the

Park, and would be less than emissions produced by the generator. Use of the propane generator at

the Wawona Point communications shed would continue under Alternative 2, resulting in no change

in air or greenhouse gas emissions from this source. If a generator is needed for a lift station, it would

be operated using best management practices to reduce greenhouse gas emissions, utilizing

alternative power sources, if feasible.

Alternative 2 includes the replacement of the vault toilets in the lower Grove area with flush toilets,

contingent upon the determination of feasibility for a septic system in this area. This replacement

would eliminate the existing odor impacts associated with the lower Grove vault toilets.

Impact Significance. Long­term, site­specific, moderate, beneficial impact.

Conclusion. Construction activity would generate short­term minor increases in air and greenhouse

gas emissions at the Mariposa Grove and the South Entrance. Operation­related activities would

generate beneficial air and greenhouse gas impacts within the Grove due to removal of most privately

owned vehicle travel within this area. The nuisance odors associated with the existing lower Grove

vault toilets would be eliminated if replaced with flush toilets. Emissions from prescribed burns in

and near the Mariposa Grove would result in moderate, short­term adverse effects during burn

events. Overall effects of Alternative 2 construction, restoration, and operations on air and

greenhouse gas emissions would be long­term, moderate, and beneficial.

Cumulative Impacts. Regional past, present, and reasonably foreseeable future projects would be the

same as under Alternative 1 (No Action)—long­term, adverse, and moderate. The primary source of

restoration­related air and greenhouse gas emissions are prescribed fires used to reduce hazardous

fuels in the Grove vicinity. These controlled burns are used to reduce the likelihood of catastrophic,

uncontrolled fires that could damage or destroy the Grove. These controlled fires are limited to times

when meteorological conditions favor dispersion of air pollutants while minimizing impacts on

individuals. However, even under controlled conditions, these fires can dramatically worsen air quality

during and after burns, and can affect sensitive individuals in the vicinity of the fire.

Overall under Alternative 2, there would be short­term, site­specific, minor adverse impacts on air

quality through minor additional emissions during construction activities and restoration­related

projects. There would be long­term moderate beneficial impacts on overall air quality under

Alternative 2 due to removal of most privately owned vehicle travel and the commercial tram in the

Mariposa Grove. Regional past, present, and future impacts, in conjunction with the local, moderate

beneficial impacts on air quality under Alternative 2, would result in a long­term minor adverse

impact on air quality in the Yosemite region.

Alternative 3: Grizzly Giant Hub

Under Alternative 3, the lower Grove parking lot and gift shop would be removed, the lower Grove

comfort station would be replaced with a smaller vault toilet facility, the asphalt in­Grove access

road would be replaced with a hardened surface, the water line from the upper Grove tank to the

South Entrance would be upgraded, commercial tram staging and operations would be eliminated,

and a new bypass road would be constructed, (including two new bridges), to serve new visitor

facilities. A new larger parking lot near the Grizzly Giant, but outside giant sequoia habitat, would be

constructed, making the Grizzly Giant the primary departure point for visitors to the Grove.

Numerous other rehabilitation and Grove restoration actions, such as improvement of hydrologic

flow, prescribed fire treatment, soil decompaction, and improvement of visitor orientation and

interpretation, would be components of this alternative.

Final Environmental Impact Statement 3­90 October 2013

Chapter 3: Affected Environment and

Environmental Consequences
             

               

   

         

                           

                             

                       

                           

                           

                       

   

                         

                 

                       

         

                         

                         

                           

                                

                     

                           

                       

                     

                             

                           

                           

                       

                

                             

                             

                             

                      

     

             

                       

                     

                         

                                 

                          

        

                   

                               

                               

                               

                               

                               

                             

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Restoration of the Mariposa Grove of Giant Sequoias
 

Construction­related Impacts. Construction of a new bypass road, two new bridges, and a new

parking area at the Grizzly Giant would generate short­term air and greenhouse gas emissions. This

includes fugitive dust and exhaust emissions from construction vehicles and equipment. Paving

would generate ROG emissions associated with off­gassing of asphalt as it cools and hardens, while

parking lot striping and painting of new and refurbished structures also would generate short­term

ROG emissions associated with evaporation of the volatile organic compounds included in paints

and stains.

Also, modifications to the lower Grove area that include removing the commercial tram staging,

fueling, and ticketing facilities would generate short­term, site­specific emissions from construction

activities. These would include exhaust emissions from construction equipment and dust from

equipment operating on exposed earth.

Removal of existing structures and construction of new facilities would generate dust, including

PM10 and PM2.5 (primarily fugitive dust from demolition activities and tailpipe emissions from the

operation of heavy­duty and hand­held equipment). Dust emissions would vary from day to day,

depending on the level and type of activity, silt content of the soil, and weather conditions.

Emissions generated from construction and demolition activities would also include tailpipe

emissions from heavy­duty equipment, worker commute trips, and truck trips to haul debris to

appropriate disposal or reuse sites, and to supply the site with construction materials. Both mobile

and stationary equipment would generate emissions of criteria pollutants (i.e. ozone precursors,

carbon monoxide, PM10, and PM2.5), and toxic air contaminants and greenhouse gases from the use

of diesel­ and gasoline­ powered equipment. Toxic air contaminants are less pervasive in the

atmosphere than criteria air pollutants, but they are linked to short­term (acute) and long­term

(chronic and/or carcinogenic) adverse human health effects. Neither toxic air contaminants nor

greenhouse gases have corresponding ambient air quality standards.

The temporary duration of the construction period would limit the potential for tailpipe emissions of

criteria pollutants and toxic air contaminants to adversely affect local air quality. In addition, visitors

would be exposed to construction emissions for the limited period of time associated with their visit.

Visitor use of and access to construction zones would be restricted.

Impact Significance. Short­term, site­specific, minor, adverse impact.

Restoration­related Impacts. Short­term increases in criteria pollutants, toxic air contaminants,

and greenhouse gas emissions would result from restoration activities similar to those described

above under construction­related impacts. Restoration­related air emissions would be generated by

activities requiring the use of off­road construction equipment (typically powered by gasoline or

diesel fuel), by worker trips, and by hauling of materials to and from the site. Restoration activities

may also generate dust that could be a nuisance to workers or visitors.

Impact Significance. Short­term, site­specific, minor, adverse impact.

Operations­related Impacts. Overall emissions associated with vehicle trips within the Mariposa

Grove area would increase as compared to Alternative 1. This is because, compared to Alternative 1,

Alternative 3 would result in a substantial increase in visitors parking at Grizzly Giant, as compared

to visitors parking in the lower Grove area (under Alternative 1). Alternative 3 would also slightly

increase the number of tour buses parking at Grizzly Giant, as compared to the number that

currently park in the lower Grove area. Alternative 3 would also eliminate shuttles from the Wawona

Store and the South Entrance. By increasing the number of visitor vehicles traveling to Grizzly Giant

Final Environmental Impact Statement 3­91 October 2013

Chapter 3: Affected Environment and

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Natural Resources: Air Quality and Climate Change

Restoration of the Mariposa Grove of Giant Sequoias

while decreasing the number of shuttle buses, exhaust and dust emissions from vehicles traveling on

this road segment would increase as compared to Alternative 1.

The generator used to power the lower Grove gift shop would be moved to the Grizzly Giant Hub

area. However, there would be no change in the emissions associated with the generator. Use of the

propane generator at the Wawona Point communications shed would continue under Alternative 2,

resulting in no change in air or greenhouse gas emissions from this source.

Alternative 3 includes the replacement of the 8 vault toilets in the lower Grove area with 2 vault

toilets. This would reduce but not eliminate the odor impacts associated with these facilities.

Alternative 3 also includes replacing 1 vault toilet at Grizzly Giant with 18 vault toilets. This change

would increase odor impacts at Grizzly Giant.

Impact Significance. Long­term, site­specific, moderate, beneficial impact.

Conclusion. Construction activities would generate short­term minor increases in air and

greenhouse gas emissions at the Mariposa Grove and the South Entrance. Operations­related

activities would generate a moderate increase in air emission impacts within the South Entrance to

Grizzly Giant Hub area because visitor vehicle travel would increase on Mariposa Grove Road.

Nuisance odors associated with the existing lower Grove vault toilets would be reduced by reducing

the number of vault toilets. However, nuisance odors would increase at Grizzly Giant due to

increases in the number of vault toilets at this location. Emissions from prescribed burns in and near

the Mariposa Grove would result in moderate, short­term adverse effects during burn events.

Overall effects of Alternative 3 construction, restoration, and operations on air and greenhouse gas

emissions would be long­term, moderate, and adverse.

Cumulative Impacts. Regional past, present, and reasonably foreseeable future projects would be

the same as under Alternative 1 (No Action)—long­term, adverse, and moderate. The primary source

of restoration­related air and greenhouse gas emissions are prescribed fires used to reduce

hazardous fuels in the Grove vicinity. These controlled burns are used to reduce the likelihood of

catastrophic, uncontrolled fires that could damage or destroy the Grove. These controlled fires are

limited to times when meteorological conditions favor dispersion of air pollutants while minimizing

impacts on individuals. However, even under controlled conditions, these fires can dramatically

worsen air quality during and after burns, and can affect sensitive individuals in the vicinity of the

fire.

Under Alternative 3, there would be long­term, site­specific, moderate adverse impacts on air quality

because of increased private vehicle emissions in the Grove area. Regional past, present, and future

impacts, in conjunction with the local, moderate adverse impacts on air quality under Alternative 3,

would result in a long­term moderate adverse impact on air quality in the Yosemite region.

Alternative 4: South Entrance Hub with Modified Commercial Tram Access

Alternative 4 would maintain the commercial tram but with a limited route and hours of operation

while also relocating the majority of the parking to the South Entrance, making the South Entrance

the primary departure point for visitors to the Grove. Though the existing trams are fairly new, the

park would replace the existing trams with a more energy­efficient hybrid vehicles as the units

approach the end of their useful life and require replacement. Numerous other rehabilitation and

restoration actions, such as improvement of hydrologic flow, project­specific prescribed fire and

hazardous fuel reduction treatments, soil decompaction, and improvement of visitor orientation and

interpretation, would be components of this alternative.

Final Environmental Impact Statement 3­92 October 2013

Chapter 3: Affected Environment and

Environmental Consequences
             

               

   

         

                 

                             

                         

                     

                             

                   

                         

                         

                         

                                       

    

                     

                           

                       

                       

                         

                           

                           

                     

          

                             

                           

                             

      

       

                     

                 

                           

                                 

                                 

  

        

                 

                           

                         

                             

                               

                                 

                         

                        

                                 

                               

                         

Natural Resources: Air Quality and Climate Change

Restoration of the Mariposa Grove of Giant Sequoias

Construction­related Impacts. Construction of parking areas and associated support infrastructure

at the South Entrance would generate air and greenhouse gas emissions that include site grading and

paving activities. These activities would generate air and greenhouse gas emissions from off­road

construction vehicles. Parking lot paving would also generate ROG emissions associated with offgassing of asphalt as it cools and hardens. Parking lot striping would generate short­term ROG

emissions from evaporation of volatile organic compounds included in paints.

Demolition and removal of existing structures and construction of relocated and new facilities

would generate dust, including PM10 and PM2.5 (primarily fugitive dust from demolition activities

and tailpipe emissions from the operation of heavy­duty and hand­held equipment). Dust emissions

would vary from day to day, depending on the level and type of activity, silt content of the soil, and

weather conditions.

Emissions generated from construction and demolition activities would also include tailpipe

emissions from heavy­duty equipment, worker commute trips, and truck trips to haul debris to

appropriate disposal or reuse sites, and to supply the site with construction materials. Both mobile

and stationary equipment would generate emissions of criteria pollutants (ozone precursors, carbon

monoxide, PM10, and PM2.5), toxic air contaminants from the use of diesel­ and gasoline­powered

equipment, and greenhouse gases. Toxic air contaminants are less pervasive in the atmosphere than

criteria air pollutants, but they are linked to short­term (acute) and long­term (chronic and/or

carcinogenic) adverse human health effects. Neither toxic air contaminants nor greenhouse gases

have corresponding ambient air quality standards.

The temporary duration of the construction period would limit the potential for tailpipe emissions of

criteria pollutants, toxic air contaminants, and greenhouse gases to adversely affect local air quality.

In addition, visitors would be exposed to construction emissions for the limited period of time

associated with their visit.

Impact Significance. Short­term, site­specific, minor, adverse impact.

Restoration­related Impacts. Short­term increases in air emissions would result from restoration

activities similar to those described above under construction­related impacts. Restoration­related

air emissions would be generated by activities requiring the use of off­road construction equipment

(typically powered by gasoline or diesel fuel), by employee trips, and by hauling of materials to and

from the site. Restoration activities may also generate dust that could be a nuisance to workers or

visitors.

Impact Significance. Short­term, site­specific, minor, adverse impact.

Operation­related Impacts. Compared to existing conditions, commercial tram emissions would be

reduced because commercial trams would operate for a fewer number of hours between the South 

Entrance and the lower Grove area. Visitor vehicle travel, except for private vehicles with placards,

would be eliminated between the South Entrance Hub and the lower Grove area, while the number

of shuttles would increase. The majority of those shuttles would be trips from the South Entrance to

the lower Grove area, while the remaining shuttles would be trips from the Wawona Store to the

Mariposa Grove. Consequently, exhaust and dust emissions from vehicles traveling on this road

segment would be reduced, as visitor vehicle trips are replaced by shuttles.

The generator used to power the lower Grove gift shop would be moved to the South Entrance Hub

area where electrical power would be used in lieu of the generator. This switch would eliminate the

criteria pollutant, toxic air contaminant, and greenhouse gas emissions produced by the generator.

Final Environmental Impact Statement 3­93 October 2013

Chapter 3: Affected Environment and

Environmental Consequences
             

               

   

         

                           

                     

                                 

                           

                           

                                     

                     

    

                           

                           

                       

     

                     

                     

                           

                           

                         

                   

                       

             

                   

                           

                       

                               

                         

                         

                     

                                 

  

                         

                 

                               

                             

                         

                         

                         

                     

                               

                                 

                             

                             

                               

Natural Resources: Air Quality and Climate Change
 

Restoration of the Mariposa Grove of Giant Sequoias
 

However, there would still be indirect criteria pollutant, toxic air contaminant, and greenhouse gas

emissions associated with the electrical generation used to supply the gift shop, though such 

emissions would be produced outside of the Park, and would be less than emissions produced by the

generator. Use of the propane generator at the Wawona Point communications shed would continue

under Alternative 4, resulting in no change in criteria pollutant, toxic air contaminant or greenhouse

gas emissions from this source. If a generator is needed for a lift station, it would be operated using

best management practices to reduce greenhouse gas emissions, utilizing alternative power sources,

if feasible.

Alternative 4 includes the replacement of the vault toilets in the lower Grove area with flush toilets,

contingent upon the determination of feasibility for a septic system in this area. This replacement

would eliminate the existing odor impacts associated with the lower Grove vault toilets.

Impact Significance. Long­term, site­specific, minor, beneficial impact.

Conclusion. Construction would generate short­term minor increases in criteria pollutant, toxic air

contaminant, and greenhouse gas emissions. Operation­related activities would generate a beneficial

reduction in air emissions within the South Entrance to lower Grove area because visitor vehicle

travel would be eliminated on Mariposa Grove Road and commercial tram activity would be

reduced. The nuisance odors associated with the existing lower Grove vault toilets would be

eliminated by replacement with flush toilets. Overall effects of Alternative 4 construction,

restoration, and operations on criteria pollutant, toxic air contaminant, and greenhouse gas

emissions would be long­term, minor, and beneficial.

Cumulative Impacts. Regional past, present, and reasonably foreseeable future projects would be

the same as under Alternative 1 (No Action)—long­term, adverse, and moderate. The primary source

of restoration­related air and greenhouse gas emissions are prescribed fires used to reduce

hazardous fuels in the Grove vicinity. These controlled burns are used to reduce the likelihood of

catastrophic, uncontrolled fires that could damage or destroy the Grove. These controlled fires are

limited to times when meteorological conditions favor dispersion of air pollutants while minimizing

impacts on individuals. However, even under controlled conditions, these fires can dramatically

worsen air quality during and after burns, and can affect sensitive individuals in the vicinity of the

fire.

Under Alternative 4, there would be short­term, site­specific, minor adverse impacts on air quality

through minor additional emissions during construction activities and restoration­related projects.

There would be long­term minor beneficial impacts on overall air quality under Alternative 4 due to

removal of most privately owned vehicle travel in the Mariposa Grove. Regional past, present, and

future impacts, in conjunction with local, minor beneficial impacts under Alternative 4, would result

in a long­term minor adverse impact on air quality in the Yosemite region.

SOUNDSCAPES

Affected Environment

Noise is generally defined as loud, unpleasant, unexpected, or undesired sound that is typically

associated with human activity and interferes with or disrupts other activities. The responses of

individuals to similar noise events are diverse and influenced by many factors, including the type of

noise, the perceived importance of the noise, its appropriateness to the setting, the time of day and

the type of activity during which the noise occurs, and noise sensitivity of the individual. Wildlife

species may have different sensitivities to sound, and these sensitivities may vary based on activity

and/or season (e.g., nesting birds or denning mammals may be more sensitive to noise intrusion than

Final Environmental Impact Statement 3­94 October 2013

Chapter 3: Affected Environment and

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Natural Resources: Soundscapes

Restoration of the Mariposa Grove of Giant Sequoias

animals engaged in more transitory activities such as foraging). Although exposure to high noise

levels has been demonstrated to cause hearing loss, the principal human and wildlife response to

typical environmental noise exposure levels is annoyance.

The standard unit of sound measurement is the decibel (dB). The range of audible sound levels for

humans is generally considered from 0­130 dBA. Table 3­8 presents approximate decibel levels of

commonly known outdoor sound sources.

Table 3­8 – Approximate Decibel Levels of Common Sound Sources (NPS 2006)

dBA Perception Outdoor Sounds

90 Very noisy Lawn mower

80 Diesel truck 50 mph at 50 feet

70 Noisy 2­stroke snowmobile 30 mph at 50 feet

60 4­stroke snowmobile 30 mph at 50 feet

50 Moderate Croaking raven flyover at 100 feet

40 River at 100 feet

30 Quiet Summer wilderness

20 Very quiet Winter wilderness

10 Barely audible Below standard noise floor

0 Limit of audibility Quiet winter wilderness

Applicable Laws, Ordinances, Regulations, and Standards

There are a number of laws and guidelines at the federal level that direct the consideration of a broad

range of noise issues, including the Noise Control Act of 1972, EPA recommendations regarding

environmental noise levels (EPA 1974), and NPS recommendations (NPS 2006). The EPA

recommends a 55 Ldn exterior and 45 Ldn interior noise threshold for noise­sensitive receptors. The

NPS states that the “type, magnitude, duration, and frequency of occurrence of noise that is

compatible or incompatible with protecting the resources or the visitor experience for which the

park was established and planned” are all factors to be taken into account when assessing noise

impacts, including determining whether certain noise sources are necessary or appropriate.

Existing Noise Sources. Noise types and levels in the study area vary based on the number of

vehicles, visitors, proximity to vehicle traffic and stationary noise sources, natural sounds

topography, weather, and other site­specific conditions. Although natural sounds contribute to

ambient noise levels, NPS considers these as part of a web of natural and cultural resources.

Mechanical sources of noise within Yosemite National Park include construction equipment,

generators, radios, and park maintenance equipment. Noise from these sources varies by season and

by distance from source.

Within the study area, motor vehicle noise is most noticeable along Wawona Road at the South 

Entrance, where there is a concentration of park visitors, vehicle traffic is heavy, and the topography

places visitors near roads. However, the existing noise environment changes throughout the year

directly in proportion to the level of use (i.e. the number of cars and buses that travel the various

roadways in the park); therefore, noise levels are generally lower during the winter than during the

summer months when there are the most visitors to the park. Noise from motor vehicles is loudest

adjacent to the roadways, but due to generally low background sound levels, can be audible a long

distance from the roads. Atmospheric effects such as wind, temperature, humidity, topography, rain,

fog, and snow can affect the presence or absence of motor vehicle noise.

Final Environmental Impact Statement 3­95 October 2013

Chapter 3: Affected Environment and

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Over the last two years Yosemite National Park has been collaborating with the NPS Natural Sounds

Program and the Sierra Nevada Network—a network of national parks in the area—to establish a

baseline for sounds in the park.

Mariposa Grove Setting

Ambient noise levels vary among the upper Grove area, lower Grove area, Wawona Point, and the

South Entrance. Natural sounds within the Mariposa Grove are not considered to be noise. These

sounds result from natural sources such as flowing water, birds and other wildlife, wind, and rustling

tree leaves. The existing noise within the Grove results from mechanical sources such as the

commercial tram, other motor vehicles, generators and aircraft, and from human activities, such as

talking and yelling.

Due to the number of motor vehicles, visitors and road location, the lower Grove parking lot is the

noisiest area of the Mariposa Grove. The soundscapes are increasingly quiet as one travels from the

lower Grove parking lot toward the Grizzly Giant as vehicular traffic is confined largely to occasional

commercial trams and the number of visitors decreases. From the Grizzly Giant to the upper Grove

area noise again decreases as visitation decreases and the upper Grove area is generally quiet except

for noise from the tram, which occurs about every 20 minutes during peak use periods. The

commercial tram recording has also been noted as a distracting noise element for those visiting the

Grove near the tram’s route. Noise measurements conducted by the NPS at the Mariposa Grove near

the museum in the upper Grove area showed the background noise levels ranged from 21 to 27 dBA

L90 during the fall, and from 20 to 26 dBA L90 during the summer. These are largely within summer

wilderness levels (see table 3­8). Wawona Point is situated further from the commercial tram traffic

of the upper Grove area and visitation is low, therefore it is among the quietest portions of the study

area.

South Entrance Setting

The South Entrance is the noisiest soundscape due to the amount of vehicle traffic and visitors.

Noise data are not available for the South Entrance, but noise levels likely vary from the 20 to 60 dBA

L90 depending on time of day and the season.

Environmental Consequences

Impacts related to soundscapes were assessed in terms of duration, type, and intensity of impact.

Unless otherwise noted, local impacts were considered to be those that occur in the immediate

vicinity of an action or in a nearby area indirectly affected by the action.

Type of Impact. Beneficial impacts are those impacts that decrease noise, and adverse impacts are

those impacts that increase noise.

Intensity of Impact. The level of impact (negligible, minor, moderate, or major) of sound changes

from the no action alternative to the action alternatives was evaluated using the following definitions.

A negligible impact indicates the change in sound levels would not be perceptible to normal human

hearing. A minor impact indicates the change in sound levels would be perceptible, but not likely to

have a substantial annoyance effect on visitors or residents in the area. A moderate impact indicates

the change in sound levels would be easily perceptible and likely to result in annoyance to some park

visitors and residents. A major impact indicates the change in sound levels would be perceptible and

likely to annoy most park visitors and residents who experience it.

Final Environmental Impact Statement 3­96 October 2013

Chapter 3: Affected Environment and

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Natural Resources: Soundscapes

Restoration of the Mariposa Grove of Giant Sequoias

Alternative 1: No Action

Under Alternative 1 current infrastructure, concessioner services and maintenance, and park

management would remain as is. No rehabilitation and restoration actions, such as improvement of

hydrologic flow and universal access, project­specific prescribed fire and hazardous fuel reduction

treatments, soil decompaction, and improvement of visitor orientation and interpretation, would be

implemented.

Operation­related Impacts. Alternative 1 does not change to the current park operations. Noise

levels from park operations would remain the same and noise levels relating to long­term operations

would be unchanged from existing conditions. Negligible seasonal/daily fluctuations in noise levels

would occur based on visitor and motor vehicle volume. Noise levels would increase if there are

more visitors due to the generation of more vehicular­related traffic and conversation.

Impact Significance. The anticipated impacts on noise under Alternative 1 would be local, longterm, moderate, and adverse.

Conclusion. The continued use of the commercial tram and motor vehicles would result in

moderate long­term adverse impacts on visitors to the Grove

Cumulative Impacts. Cumulative impacts on the soundscape are based on analysis of past, present,

and reasonably foreseeable future actions in the Mariposa Grove area in conjunction with the

potential effects of each alternative. Past, present, and reasonably foreseeable future actions affecting

soundscapes include numerous small­scale construction and rehabilitation projects at the South 

Entrance and the Mariposa Grove (Appendix B). These projects would have minor to moderate

short­term, site­specific adverse impacts in the Mariposa Grove area. Alternative 1 would result in

moderate, long­term adverse impacts on the soundscape of the Grove from the continued use of the

commercial tram and motor vehicles. Past, present, and future actions in conjunction with the

impacts of Alternative 1 would have a long­term, moderate adverse impacts on soundscapes in the

Mariposa Grove area.

Alternative 2: South Entrance Hub (Preferred Alternative)

Alternative 2 would remove the commercial tram operation and replace the 115­space parking lot in

the lower Grove area with 8 accessible and 25­50 standard spaces while expanding and relocating

primary visitor parking to the South Entrance, making the South Entrance the departure point for

visitors accessing the Grove. Numerous other rehabilitation and restoration actions, such as

improvement of hydrologic flow and universal access, project­specific prescribed fire and hazardous

fuel reduction treatments, soil decompaction, and improvement of visitor orientation and

interpretation, would be components of this alternative.

Construction­related Impacts. Construction activities would generate the most noise of all the

activities under Alternative 2. The construction activities at the South Entrance would include the

construction of a new parking area; construction of the visitor contact area and related bathroom

facilities; construction of shuttle boarding and tour bus transfer area; construction of a new leach 

field and replacement of an existing leach field (if feasible); and construction of a new

chlorination/water tank. The noise­generating construction activities in the lower Grove area would

be the removal of the commercial tram staging area; construction of the new roadway alignment and

vehicular bridge at the entrance curve; reduction of the parking area; construction of new hardened

road for service access using old road alignments; extension of the footbridge; construction of new

bathroom facilities; construction of a new leach field (if feasible); and removal of the gift shop. The

major noise­generating construction activity near the Grizzly Giant would be the removal of the

Final Environmental Impact Statement 3­97 October 2013

Chapter 3: Affected Environment and

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existing vault toilets and installation of new vault toilets at the accessible drop­off area. The noisegenerating construction activities in the upper Grove area would be the relocation of the water tank,

removal of the existing vault toilets; and rehabilitation and repair of the water pipeline. Conversion

of the Mariposa Grove Road from pavement to a hardened surface and conversion of the loop road

in the upper Grove area to a pedestrian trail would involve heavy equipment and resultant noise. A

conservative estimate of noise generated by construction activities is 89 dBA Leq at a distance of

50 feet. Expected construction activities include minor excavation, grading, clearing, and paving.

Construction activities would generate temporary increases in noise exposure in the vicinity of

project construction when heavy machinery and equipment is used.

Impact Significance. Local, short­term, moderate, and adverse.

Restoration­related Impacts. Restoration activities would include a 50 percent reduction of

impermeable surface within the lower Grove area. The surface would be made available for giant

sequoia habitat restoration, soil decompaction, and water infiltration. Insufficient culverts and/or

cross drains would be cleaned, repaired, or replaced. Mariposa Grove Road, or the trail, would be

outsloped where site­specific conditions allow. Implementing fire management activities to thin

trees and remove understory vegetation and fuels would result in local increases in noise.

Construction to implement sustainable stormwater strategies and repair the waterline would also

increase noise. Similar to noise from construction activities, a conservative estimate of noise

generated by restoration activities is 89 dBA Leq at a distance of 50 feet. Expected restoration

activities include minor excavation, grading, and clearing activities. Restoration activities would

generate temporary major increases in noise exposure in the vicinity of restoration areas when heavy

machinery and equipment is used.

Impact Significance. Impacts from construction noise would be local, short­term, moderate, and

adverse.

Operation­related Impacts. Implementation of Alternative 2 would reduce the number of motor

vehicle using the Mariposa Grove Road. Equipment and infrastructure associated with the Visitor

Contact Area would be moved from the Grove to the South Entrance. Shuttles and buses would

continue drop­offs in the lower Grove area, but the circular shuttle drop­off in the lower Grove area

would reduce backing alert noise. Removal of the commercial tram from the Grove would reduce

vehicle noise. Removal of the parking lot in the lower Grove area would result in a lower level of

noise generated by vehicular traffic. Removal of the generator associated with the gift shop would

reduce noise in the lower grove area. However, a new generator may be needed for a lift station but

would be enclosed with acoustic panels to deaden the sound. Removal of the gift shop will also

remove noise associated with delivery trucks arriving, unloading supplies, and backing up within the

lower Grove area.

Impact Significance. Impacts from operation related noise would be local, long­term, major, and

beneficial.

Conclusion. The reduction in the number of vehicles using the Mariposa Grove Road, removal of

the commercial tram tour, and minimization would reduce noise levels generated by operations.

Experience in the lower portion of the Grove would now be more like that in more isolated areas of

Mariposa Grove and allows visitors to experience natural quiet and sounds.

Cumulative Impacts. The impacts of regional past, present, and reasonably foreseeable future

projects would be the same as under Alternative 1 (No Action)—minor to moderate short­term, sitespecific adverse impacts in the Mariposa Grove area. The long­term impacts of Alternative 2 would

Final Environmental Impact Statement 3­98 October 2013

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Natural Resources: Soundscapes

Restoration of the Mariposa Grove of Giant Sequoias

result in major, long­term beneficial impacts on the soundscape of the Grove from reductions in

motor vehicle use, elimination of the commercial tram, and reduced operations in the Grove. Past,

present, and future actions in conjunction with the impacts of Alternative 2 would have a long­term,

major beneficial impact on soundscapes in the Mariposa Grove area.

Alternative 3: Grizzly Giant Hub

Alternative 3 would remove the commercial tram operation and build a new bypass road, including

two new bridges, and a new larger parking lot near the Grizzly Giant, but outside of giant sequoia

habitat. This alternative would make the Grizzly Giant the primary departure point for visitors to the

Grove. The current South Entrance parking lot would remain as is, and the lower Grove parking lot

would be replaced with a smaller lot of ABAAS­compliant parking spaces. Numerous other

rehabilitation and restoration actions, such as improvement of hydrologic flow and universal access,

project­specific prescribed fire and hazardous fuel reduction treatments, soil decompaction, and

improvement of visitor orientation and interpretation, would be components of this alternative.

Construction­related Impacts. The major noise­generating construction activities at the lower

Grove area related to the implementation of Alternative 3 would be the removal of the commercial

tram; removal of the parking area and the addition of 10 ABAAS parking spaces; construction of 2

new vault bathrooms; construction of two vehicular bridges and the new grove bypass road; removal

of the commercial tram staging, fueling and ticketing area, gift shop, visitor information kiosks, and

shuttle/bus parking area; and extension of the footbridge. The greatest noise­generating

construction activities at Grizzly Giant would be the removal of the commercial tram; construction

of the visitor contact area that includes the museum and information center; construction of 18 space

bathroom; construction of a parking area that includes about 233 available spots, construction of the

new grove bypass road that originates from the lower Grove area; and construction of a tour bus

parking area. The main noise­generating construction activity near the Grizzly Giant would be the

removal of the existing vault toilets. The major noise­generating construction activities in the upper

Grove area would be the removal of the commercial tram; removal of the vault toilet area; and

rehabilitation and repair activities at the comfort station. The conservative estimate level of noise

generated by construction activities is expected to be the same as Alternative 2. Expected

construction activities include minor excavation, grading, clearing, and paving activities.

Construction activities would generate temporary increases in noise exposure in the vicinity of

project construction when heavy machinery and equipment is used.

Impact Significance. Impacts from construction activities would be local, short­term, moderate,

and adverse.

Restoration­related Impacts. Restoration activities related to the implementation of Alternative 3

would be along the road in between the lower Grove area and the Grizzly Giant Hub, east of the

hardened narrow road in between Grizzly Giant and the upper Grove area, and throughout a

majority of the northern loop in the upper Grove near the roadways. Restoration activities include a

82 percent reduction of impermeable surface within the lower Grove area made available for giant

sequoia habitat restoration, soil decompaction, and water infiltration. Similar to Alternative 2,

restoration activities would generate temporary increases in noise exposure in the vicinity of

restoration areas when heavy machinery and equipment is used.

Impact Significance. Impacts from restoration activities would be local, short­term, moderate, and

adverse.

Operation­related Impacts. Implementation of Alternative 3 would introduce new traffic along the

new Grove Bypass Road. Equipment and infrastructure associated with the Visitor Contact Area

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would be moved from the Grove to the Grizzly Giant Hub, but an effort would be made to specify

quiet and sustainable equipment. The lack of existing facilities at the Grizzly Giant Hub may call for

the need for generators for concessioner operations. Generators may potentially generate noise

levels that range from 73 to 81 dBA Leq at a distance of 50 feet. Noise levels may be reduced through 

the use of acoustic panels or enclosures. Shuttles and buses would now have drop­offs at the Grizzly

Giant hub, but a circular tour bus drop­off would minimize backing alert noises. The commercial

tram would be removed from the Grove which results in the elimination of engine/vehicular noise.

Parking relocation from the Grove to the Grizzly Giant hub would reduce traffic noise in the lower

Grove area if all vehicles parking at the Grizzly Giant hub travel at low speeds along Grove Bypass

Road.

Impact Significance. Impacts from operations would be local, long­term, moderate, and beneficial

to the lower Grove area and local, long­term, moderate, and adverse in the mid­Grove area of the

Grizzly Giant.

Conclusion. For Alternative 3, noise levels would increase temporarily when construction and

restoration activities are being conducted. The removal of the commercial tram would reduce the

operational noise level, but this would be partially offset by noise from vehicles traveling along the

new access road and at the new parking lot and the influx of visitors at the Grizzly Giant, roughly the

middle of the Grove in terms of elevational gradient.

Cumulative Impacts. The impacts of regional past, present, and reasonably foreseeable future

projects would be the same as under Alternative 1 (No Action)—minor to moderate short­term, sitespecific adverse impacts in the Mariposa Grove area. Long­term impacts under Alternative 3 on the

soundscape would be moderate and beneficial from removal of the commercial tram. This would be

offset in part by noise from vehicles traveling along the new access road and the Grizzly Giant hub.

Past, present, and future actions in conjunction with the impacts of Alternative 3 would have a longterm, moderate beneficial impact on soundscapes in the Mariposa Grove area.

Alternative 4: South Entrance Hub with Modified Commercial Tram Access

Alternative 4 would maintain the commercial tram but with a limited route and hours of operation

while also relocating the majority of the parking to the South Entrance, making the South Entrance

the primary departure point for visitors to the Grove. Numerous other rehabilitation and restoration

actions, such as improvement of hydrologic flow, project­specific prescribed fire and hazardous fuel

reduction treatments, soil decompaction, and improvement of visitor orientation and interpretation,

would be components of this alternative.

Construction­related Impacts. The major noise­generating construction activities at the South 

Entrance related to the implementation of Alternative 4 would be the construction of the visitor

contact area that includes new visitor services such as visitor information, educational and other

sales items, and bathroom facilities; construction of a new parking area; construction of shuttle

boarding and tour bus transfer area; construction of a new leach field and replacement of an existing

leach field (if feasible); and construction of new chlorination/water tank. The major noise­generating

construction activities near the lower Grove area would be the construction of the new narrow

paved road for commercial tram and service access using the old road alignment; extension of the

footbridge; removal of current parking area; construction of seasonal parking area; construction of

new bathroom facilities; construction of a new leach field (if feasible); removal of the gift shop; and

construction of a commercial tram ticket and waiting area. The major noise­generating construction

activities near the upper Grove area would be the removal of the commercial tram from that area;

removal of the water tank; removal of the vault toilets; and rehabilitation and repair activities at the

comfort station. A conservative estimate of noise generated by construction activities is 89 dBA Leq at

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a distance of 50 feet. Expected construction activities include minor excavation, grading, clearing,

and paving activities. Construction activities would generate temporary increases in noise exposure

in the vicinity of project construction when heavy machinery and equipment is used.

Impact Significance. Impacts from construction activities would be local, short­term, moderate,

and adverse.

Restoration­related Impacts. Restoration activities related to the implementation of Alternative 4

would be south of the Mariposa Grove Road immediately east and adjacent to the lower Grove Hub

and throughout a majority of the upper Grove area near the roadways. Restoration activities include

a 55 percent reduction of impermeable surface within the lower Grove area made available for giant

sequoia habitat restoration, soil decompaction, and water infiltration. Dysfunctional culverts and/or

cross drains would be cleaned, repaired, or replaced. Mariposa Grove Road, or the trail, would be

outsloped where site­specific conditions allow. The fire management program would continue and

would be adapted to measures necessary in order to prevent spread of future fires. Sustainable

stormwater strategies would be implemented to intercept runoff, filter pollutants, and redistribute

rather than channelize hydrologic flow. Leaky water pipes in the upper Grove area would be

repaired and monitored. A conservative and approximate estimate of noise generated by restoration

activities is 89 dBA Leq at a distance of 50 feet. Expected restoration activities include minor excavation, grading, and clearing activities. Restoration activities would generate temporary increases in

noise exposure in the vicinity of restoration areas when heavy machinery and equipment is used.

Impact Significance. Impacts from restoration activities would be local, short­term, moderate, and

adverse.

Operation­related Impacts. Implementation of Alternative 4 would relocate a majority of parking

to the South Entrance, reduce the number of commercial tram operating hours, remove commercial

tram operations from a majority of the upper Grove area, and relocate commercial tram and related

infrastructure within the lower Grove area. commercial tram operations would be restricted. Two

commercial trams, at a maximum, would share a one­lane road with periodic turnouts. Vehicular

noise would be reduced within the lower Grove area due to the relocation of parking to the South 

Entrance. Alternative 4 would reduce vehicle trips along Wawona Road and the Mariposa Grove

Road. Equipment and infrastructure associated with the Visitor Contact Area would be moved from

the Grove to the South Entrance. Shuttles and buses would continue drop­offs in the lower Grove

Hub, but the lower Grove Hub would now have a circular shuttle drop­off that results in the

minimization of backing alert noise. Removal of the generator associated with the gift shop would

reduce noise in the lower grove area. However, a new generator may be needed for a lift station but

would be enclosed with acoustic panels to deaden the sound. Removal of the gift shop will also

remove noise associated with delivery trucks arriving, unloading supplies, and backing up within the

lower Grove area.

Impact Significance. Impacts from operations would be local, long­term, minor, and beneficial.

Conclusion. A reduction in commercial tram operations and restricted commercial tram operational

hours, along with the removal of a portion of the commercial tram throughout the upper Grove area,

would reduce operational noise levels long­term. Removal of the generator associated with the gift

shop will also reduce noise levels in the lower Grove area. Overall, there would be a long­term minor

beneficial impact on the soundscape.

Cumulative Impacts. The impacts of regional past, present, and reasonably foreseeable future

projects would be the same as under Alternative 1 (No Action)—minor to moderate short­term, sitespecific adverse impacts in the Mariposa Grove area. The long­term impacts of Alternative 4 would

Final Environmental Impact Statement 3­101 October 2013

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Natural Resources: Soundscapes

Restoration of the Mariposa Grove of Giant Sequoias

result in minor, long­term beneficial impacts on the soundscape of the Grove from reductions in

motor vehicle use, and reduced operations in the Grove. Past, present, and future actions in

conjunction with the impacts of Alternative 4 would have a long­term, minor adverse impact on

soundscapes in the Mariposa Grove area.

CULTURAL RESOURCES

HISTORIC STRUCTURES

Affected Environment

The cultural resources area of potential effect (APE) is presented in figure 3­18, and includes the

combined boundaries of the Mariposa Grove and South Entrance Station historic districts, and the

individually listed Mariposa Grove Museum. The Mariposa Grove Historic District includes the

approximately 4­square­mile area described in the original 1864 Yosemite Grant and includes the

addition of the Mariposa Grove Road between the western grant boundary and the South Entrance

Station Historic District (NPS 2004b, 2012c; California Office of Historic Preservation 2013). The

Mariposa Grove Historic District also encompasses the Mariposa Grove Archeological District (see

separate discussion under the Archeology section in this chapter). The South Entrance Station

Historic District includes “the cleared area for the housing unit on the north side of Wawona Road

and the area in the vicinity of the T­shaped intersection of the Wawona Road and Wawona Road,

sufficient to include the comfort station and check station” (NPS 2004c). The Mariposa Grove and

the South Entrance Station historic districts were previously determined eligible for listing in the

National Register (Hart 1975; NPS 2004b and 2004c), and the expansion of the Mariposa Grove

district boundary to include Mariposa Grove Road received concurrence from the California State

Historic Preservation Officer (SHPO) in February 2013.

Building upon the initial listing on the Mariposa Grove Museum in the National Register (Hart

1975), the entire Grove was determined eligible for listing in the National Register as a historic

district (NPS 2004b). Additional information, including a description of the setting, history,

important characteristics, and National Register status and eligibility of the Mariposa Grove Historic

District is provided in the Mariposa Grove Historic District subsection below.

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Cultural Resources: Historic Structures

Restoration of the Mariposa Grove of Giant Sequoias

Figure 3­18 – Cultural Resources Area of Potential Effects

Note: The Mariposa Grove Historic District Boundary encompasses the Mariposa Grove Archeological District resources.

The Mariposa Grove and Yosemite Valley were the

first public lands in American history set aside for

the preservation of its natural and scenic values

(Kirk and Palmer 2004; Greene 1987; NPS 2004b).

In 1864, Congress passed landmark legislation to

preserve Yosemite Valley and the Mariposa Big

Tree Grove (Mariposa Grove of Giant Sequoias)

(13 Stat. 325). This legislation granted the land to

the state of California to “be held for public use,

resort, and recreation” to be “inalienable for all

time.”

Figure 3­19 – Mariposa Grove Road in Upper Grove

Area

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Cultural Resources: Historic Structures

Restoration of the Mariposa Grove of Giant Sequoias

The State of California accepted the property in 1866, establishing the first state park and beginning

the California State Park System, and state parks nationwide (Greene 1987). In the fall of 1890,

Congress established Yosemite National Park (26 Stat. 650). The act excluded Yosemite Valley and

the Mariposa Big Tree Grove, leaving them under the jurisdiction of the state of California. A Joint

Resolution of Congress in June 1906 accepted the transfer of Yosemite Valley and the Mariposa Big

Tree Grove from the state of California to the federal government, subject to the provisions in the

1890 act.

The management of the Grove through the years demonstrates a long tradition of balancing visitor

use and nature. The State of California, and subsequently the United States Army and the NPS, have

managed the Grove to achieve the dual—and sometimes conflicting—objectives of preservation and

access. The Sierra Club, which was established in 1892, also influenced management of the Grove. In

the early 1900s, a consortium of landscape architects, architects, and engineers led by Sierra Club

President John Muir conceived a cohesive landscape design for the Mariposa Grove to fulfill the

demands for national park development, while preserving the notable natural qualities (McClelland

1993). The intention was to maintain the natural quality of the park as best as possible while also

providing infrastructure for lodging, camping, and supplies

for park visitors. These objectives formed the foundation

of future park policy and evolved into the creation of park

development outlines and general development plans

(McClelland 1993). Continued visitation to the Mariposa

Grove of Giant Sequoias in increasing numbers has

resulted in the construction and maintenance of roads and

trails throughout the Grove. Increased visitation over the

years also raised concerns over possible negative impacts

on the trees and led to the decision in 1969 to prohibit

private vehicles from entering the upper Grove area.

Lodges and campgrounds also have been removed from

the Grove to reduce visitor impact. The Mariposa Grove

Museum, in the upper Grove area, continues to serve as a

seasonal interpretive center for the Grove, and has been

listed in the National Register since 1978 (figure 3­20).

Additional information, including a description of the

setting, history, and important characteristics of the

museum, is included in the Mariposa Grove Museum

subsection below.

The South Entrance Station Historic District was determined eligible for listing in the National

Register in 2004 for “expressing cultural values” through its architecture and landscape architecture

(NPS 2004c). In 1932, President Herbert Hoover issued a proclamation to add 8,785 acres of the

Wawona Basin to Yosemite National Park, which included lands surrounding the South Entrance

area. A year earlier, Congress had approved this addition in the Interior Department Appropriations

Act (Proclamation 2005, Aug. 13, 1932; Act of Feb. 14, 1931, 46 Stat. 1115, 1154). One of the reasons

for approving the acquisition was to protect lands adjacent to Wawona Road, a road constructed in

1875 as a toll road to connect the Wawona Hotel area with Yosemite Valley, 30 miles to the

northwest. Reconstruction of Wawona Road began in 1929, and was largely completed by 1932. The

Mariposa Grove Road, between South Entrance and the Grove, was built in 1879 and reconstructed

by 1933. The road was paved to facilitate snow removal plow and provide year­round access. In

1934, the South Entrance area was realigned, and new parking was added.

Figure 3­20 – Mariposa Grove Museum

Final Environmental Impact Statement 3­104 October 2013

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Cultural Resources: Historic Structures

Restoration of the Mariposa Grove of Giant Sequoias

The number of visitors entering Yosemite National Park through the South Entrance station in 1933

exceeded 42,000, second only to the more than 197,000 visitors who entered the park via the Arch 

Rock Entrance station that year. A lack of funding necessitated temporary use of a checking kiosk

that had been relocated to South Entrance from Alder Creek. By July 1934, federal relief funds

became available to construct the South Entrance checking and comfort stations, as well as nearby

housing for the rangers employed in the Wawona District of the park. A sanitary sewer system also

was constructed for the South Entrance between 1933 and 1934. By 1937, a pipeline from Mariposa

Grove supplemented the South Entrance Station water system, which resolved issues with 

insufficient water flow (NPS 2004b). Additional information, including a description of the setting,

history, important characteristics, as well as the National Register status and eligibility of the South 

Entrance Station Historic District, is provided in the ‘South Entrance Setting’ subsection below.

Mariposa Grove Setting

The setting for the Mariposa Grove of Giant Sequoias encompasses the Mariposa Grove Historic

District and the Mariposa Grove Museum, which is individually listed in the National Register and

eligible as a contributor to the National Register­eligible Mariposa Grove Historic District. The

following discussion reviews the setting, history, important characteristics, and National Register

status and eligibility of these resources

Mariposa Grove Historic District

The Mariposa Grove Historic District was determined eligible for listing in the National Register in

2004 per the Mariposa Grove Cultural Landscape Inventory prepared by the NPS Pacific West Office,

which received SHPO concurrence in August 2004 (NPS 2004b). In February 2013, the expansion of

the Mariposa Grove Historic District boundary to include the length of the Mariposa Grove Road

between South Entrance and the lower Grove area received concurrence from the California State

Historic Preservation Officer (NPS 2004b, SHPO 2013). In addition, abandoned roads within the

Mariposa Grove were added as contributing elements, and detailed site plans clearly illustrating the

extent and location of the district’s contributing and noncontributing resources were provided (NPS

2012b).

The district is located on the western slope of the Sierra Nevada, approximately 2 miles from the

South Entrance to Yosemite National Park. When the district was determined eligible for listing in

the National Register in 2004, the period of significance was defined as 1864 (when the land was

withdrawn from the public domain) to 1950; however, many of the historic features date to the

1930s. The district is considered significant under National Register Criterion A for its association

with the “Conservation” and “Recreation” areas of significance. Specifically, the Grove embodies the

birth of the American ideal that the best use of lands distinguished for their great scenic beauty is

preservation, and that the best choice an enlightened federal government can make is to reserve such 

lands for all time for the enjoyment of the people. The district also is considered significant under

National Register Criterion C under the “Architecture” and “Landscape Architecture” areas of

significance. The design of the museum and the comfort station are representative of Park Rustic

architecture, and Wawona Point embodies the work of the park service’s early “naturalistic”

landscape design, which successfully balanced the need for development with the need to preserve

the natural landscape The Mariposa Grove Historic District is in fair condition and, with a few

exceptions, retains its historical integrity of setting and design (NPS 2004b).

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Cultural Resources: Historic Structures

Restoration of the Mariposa Grove of Giant Sequoias

The most important landscape characteristics associated with the Grove are the natural systems and

features of the district, and the site­specific ecology that continues to sustain the giant sequoias.

Superimposed upon the natural landscape is a transportation system that represents a continuum of

use dating to the nineteenth century, reflecting the presence of American Indians, entrepreneurs, the

State of California, the U.S. Army, and the NPS in the area, and contributing buildings and structures

that are collectively representative of NPS landscape design of the 1930s, much of it implemented by

the Civilian Conservation Corps (figures 3­20 through 3­22).

Figure 3­22 – Comfort Station in Upper Figure 3­21 – Wawona Point

Grove

Contributing Elements of the Mariposa Grove Historic District:

•	 Mariposa Grove Comfort Station (WA04726) – A log building built in 1931 in the Park Rustic

style and consisting of men’s and women’s lavatories, located in the upper part of the Grove.

The building is an excellent example of the application of site­specific materials standards to

a generally accepted “standard plan” building (NPS 2004b).

•	 Mariposa Grove Museum (WA04725) – A one­story, rectangular log building built in 1930

and rebuilt in 1980 in the Park Rustic style. The building is unique within the park service

system because it was designed to mirror the design of the previous buildings at the site (Hart

1975 and NPS 2004b). Refer to the subsection ‘Mariposa Grove Museum’ below for

additional descriptive information as an individually listed property.

•	 Mariposa Grove Road – The road that extends from its intersection with Wawona Road at

South Entrance into the western edge of the land grant boundary all the way to Wawona

Point). The road was constructed in 1931 and 1932 (NPS 2012c) and paved in 1933 and 1934.

•	 Other Roads – Within the Grove, there is a system of one­ and two­lane historic paved roads.

These additional roads include a spur road to the former construction camp and a one­way

loop road in the upper Grove area that begins near Wawona Point and extends to the

museum. The loop road was built in 1931/32 and was paved in 1933/34 to allow for yearround use. A spur road (non­contributing), that extends from the Mariposa Grove Road in

the vicinity of the Grizzly Giant to the site of a former construction camp, is all that remains

of the camp which was built circa 1931 and since demolished. (NPS 2004b and 2012).

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Cultural Resources: Historic Structures

Restoration of the Mariposa Grove of Giant Sequoias

Figure 3­23 – Mariposa Grove Historic District

•	 Mariposa Grove Dry­Laid Stone Retaining Walls – Two sections of dry­laid stone retaining

wall were built circa 1925 and incorporated into the road system between the Clothespin

Tree and the Mariposa Tree (NPS 2004b).

•	 Mariposa Grove Bridle Paths – A group of circulation paths including the bridle path to

Wawona, the outer loop bridle path, and the trail to Biledo Meadow. The bridle path to

Wawona is a 3­ to 6­foot­wide, natural­surface path built in 1933 and 1934 that enters the

district from the north and ascends near Sunset Point, where it connects with the outer loop

bridle path. The outer loop bridle path, a 3­to­6­foot­wide, natural­surface path built in 1933

and 1934, encircles the upper portion of the Grove. The trail to Biledo Meadow, built in 1931

and 1932, is a 6­foot­wide trail constructed during the installation of the water system for the

upper Grove, and extends from the vicinity of the fallen Wawona Tunnel Tree east to the

outtake point in Biledo Meadow (NPS 2004b).

•	 Mariposa Grove Historic Trail – A possible remnant of the Mann Trail, dating to 1870, that

extends from the vicinity of the museum east to meet with the northeast section of the

Mariposa Grove Road in the upper Grove area (NPS 2004b and 2012).

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Cultural Resources: Historic Structures

Restoration of the Mariposa Grove of Giant Sequoias

•	 Mariposa Grove Wagon Road – A one­way wagon road abandoned for vehicle use in 1925,

and currently used as pedestrian path. The path dates from 1879, 1892, and 1925, and passes

in the vicinity of the giant sequoia Diamond Group (southwest of the Comfort Station) and

descends southwest past the Clothespin Tree, continuing to the lower Grove parking area via

series of switchbacks (NPS 2004b).

•	 Abandoned Roads within Mariposa Grove – Abandoned roads in the Grove include the Big

Trees Lodge entry drive and parking area, constructed in 1932, and a wagon road alignment

in the lower Grove area, dating to 1879, 1897, and 1925. The wagon road alignment was

abandoned in the mid­1930s when the road was rerouted away from the Grizzly Giant to

reduce damage to the tree (NPS 2012c).

•	 Wawona Point Stone Features – A system of stone retaining walls, stairs, and overlook

platforms at Wawona Point Lookout built in 1931 of mortared, battered, and rubble masonry

(NPS 2004b).

•	 Mariposa Grove 1906 Survey Marker – A brass­cap boundary marker, dating to the 1906

survey of the grant boundary. The marker is adjacent to the north side of the Mariposa

Grove Road next to a large granite boulder above the road (NPS 2004b).

•	 Mariposa Grove Drinking Fountains – Two drinking fountains near the Mariposa Grove

Museum, constructed in 1931, consist of small basins atop pedestals of granite boulders with 

granite slab bases (NPS 2004b).

•	 Mariposa Grove American Legion Memorial Plaque – A 1921 plaque mounted on a large

granite boulder, set between the American Legion Tree and the edge of the road, that bears

the American Legion seal and the words, “To the unknown dead of the World War/the

American Legion, Department of California/Dedicates this Tree/August 26, 1921/Presented

by Yosemite Post 258” (NPS 2004b).

•	 Mariposa Grove Fire Hydrants – The fire hydrants of the upper Grove area are red miniature

versions of a standard city hydrant that were installed in 1931, and are located in the upper

Grove area (NPS 2004b).

Overall, circulation is an important cultural landscape characteristic of the Mariposa Grove Historic

District, and many of the roads and trails within the district boundaries are contributing elements of

the district. Within the Grove, the Mariposa Grove Road materials and routes were poorly

documented prior to 1925, though together they were described as a “vernacular” wagon road. In

1925, the NPS made minor modifications to the roads to create a 25­foot­wide, oiled grade in the

two­way segments, and a 10­foot­wide, oiled travel­way in the one­way loop in the upper Grove

area. The improvements were intended to address drainage problems and protect the roots of the

trees in the upper Grove area. In the 1930s, the Mariposa Grove Road was first paved and slightly

realigned in two locations: near the base of the Grizzly Giant to reroute the road away from the

roots, and in the lower Grove area to provide better access to the Big Trees Lodge. The differences in

the width of the road between the two­way and one­way segments reflect the historical pattern of

development during the 1930s. The roads have been regularly repaved, and some sections have been

reconstructed as part of routine maintenance. Modifications to the roads made during and prior to

the 1930s are considered character­defining features of the historic district.

Final Environmental Impact Statement 3­108 October 2013

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Cultural Resources: Historic Structures

Restoration of the Mariposa Grove of Giant Sequoias

The following are the character­defining features of the Mariposa Grove Historic District:

•	 Giant Sequoias –Mariposa Grove consists of approximately 500 mature giant sequoia trees

divided into two clusters generally referred to as the upper and lower Grove areas, which are

significant collectively. Three trees are distinct because of their size or character: California

Tunnel Tree, Grizzly Giant, and the fallen Wawona Tunnel Tree. The California Tunnel Tree

and the Wawona Tunnel Tree have been culturally modified. The Grizzly Giant features

prominently in the iconography of the Grove (NPS 2004b).

•	 Views and Vistas – Several important views, including first view of the Sentinels, from the

west, view of lands outside the Grove from Wawona Point, and vista of the Grizzly Giant, are

character­defining features of the district. The first view of the Sentinels is the first glimpse of

the big trees that one encounters when entering the Grove on the Mariposa Grove Road

from the west. Wawona Point is the only formally designed overlook within the Grove,

completed in 1932, with extensive views over the Wawona basin and the South Fork of the

Merced River, with additional panoramas of the east and south (now somewhat obscured by

forest canopy). The vista of the Grizzly Giant is an interior Grove view of the Grizzly Giant

looking down the access trail from the current commercial tram stop east of the tree (NPS

2004b).

•	 Native Roadside Landscaping – Roadside landscaping, consisting of plantings of native

species by Civilian Conservation Corps crews, was accomplished along the road corridor in

1934 and contributes to the natural setting of the road within the Grove. There are no

overhanging banks, no protruding root systems or stumps, and the slopes adjacent to the

road have been reshaped to conform to the surrounding scenery.

The Mariposa Grove Historic District retains the following landscape characteristics: natural

systems and features, vegetation, spatial organization, views and vistas, circulation, and

buildings/structures. Clustering, or the grouping of buildings within the landscape, was once an

important characteristic of the later, designed landscape of the Grove. However, the principal

building clusters have been removed or altered and no longer retain historic integrity. For the most

part, these changes are due to the elimination of some land uses, such as overnight guest

accommodations, from the Grove. Similarly, the Grove once contained a wealth of small­scale

features, including name signs affixed to certain trees and log benches constructed by the Civilian

Conservation Corps. The majority of the tree name signs have been removed (NPS 2004b).

Mariposa Grove Museum

The Mariposa Grove Museum, constructed in 1930 and rebuilt in 1980, is in the upper Grove area

within the historic district (figure 3­20). The building was designed to mirror the design of the

previous buildings at the site (Hart 1975, NPS 2004b). The museum was individually listed in the

National Register in 1978 (NPS 2004b), and also is considered eligible as a contributor to the

Mariposa Grove Historic District under National Register Criteria A and C for its regional

significance in the categories of exploration/settlement and social/humanitarian, and for its local

significance in architecture. The museum is a one­story log building situated in the upper Grove area.

The periods of significance for this property are 1864, 1881, and 1930, which correlate to the years

when major construction occurred (Hart 1975 and NPS 2004b).

Final Environmental Impact Statement 3­109 October 2013

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Cultural Resources: Historic Structures

Restoration of the Mariposa Grove of Giant Sequoias

The museum building continues the tradition established at its location by Galen Clark and the State

of California. Galen Clark, the first appointed guardian of the Grove, built the first shelter at the

location in 1864 as an office/information center to assist visitors. In 1881, the State of California

replaced the shelter with a one­room cabin “for the comfort and convenience of the visitor.” In 1930,

the NPS replaced the unstable log cabin with a new museum building, which was described as a

“guardian’s hospice”, and included exhibits that were devoted exclusively to the story of the giant

sequoia. The building and its furnishings were designed to harmonize with the surrounding Grove.

The Mariposa Grove Museum continues to function as an interpretive center as well as a rest area

for visitors, and retains integrity of location and use initiated with the 1864 information center. It

retains its 1930 historic integrity of design and workmanship (Hart 1975, NPS 2004b).

South Entrance Setting

The South Entrance Station Historic District encompasses the South Entrance site, and was

determined eligible for listing in the National Register in 2004 (NPS 2004c). The district is eligible for

listing in the National Register at the local level under Criterion C for embodying the theme of

“expressing cultural values” through its architecture and landscape architecture. The South Entrance

Station Historic District, depicted in figure 3­24, consists of a cluster of four historic buildings at the

intersection of the Wawona Road and the Mariposa Grove Road: the ranger residence, a garage, a

comfort station, and a checking station, all constructed in the early 1930s. The site is in a clearing of

about 2 acres surrounded by steep forested slopes.

The period of significance for this property spans the years from 1934 through 1938, the era of public

works. In 1934, the South Entrance area was realigned, and parking was added. Associated land uses

include a housing area for NPS personnel, a checking station for visitors entering and leaving the

park, a comfort station for the use of visitors and park employees, and a garage/service area. The

housing area and garage are on the north side of Wawona Road, and the checking station and

comfort station are south of the road. This entrance is the principal entry point for people entering

the park via Wawona Road from the south. The historic district is in fair condition and, with a few

exceptions, retains historical integrity (NPS 2004c).

Final Environmental Impact Statement 3­110 October 2013

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Cultural Resources: Historic Structures

Restoration of the Mariposa Grove of Giant Sequoias

Figure 3­24 – South Entrance Station Historic District

Contributing Elements of the South Entrance Historic District

•	 South Entrance Office (WA04604) – A 1934
 

checking station built in the Park Rustic style. It has
 

been remodeled to function as an office, resulting in
 

the removal of some of the architectural details
 

associated with its original function.
 

•	 South Entrance Comfort Station (WA04606) – A
 

1934 Park Rustic style building containing lavatories
 

(figure 3­25).
 

•	 South Entrance Ranger Duplex (WA04600) – The
 

1934 Park Rustic style living quarters (dormitory)
 

for Wawona District park rangers stationed at
 

South Entrance.
 Figure 3­25 – South Entrance Comfort
 

Station
 

Final Environmental Impact Statement 3­111 October 2013

Chapter 3: Affected Environment and

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Cultural Resources: Historic Structures

Restoration of the Mariposa Grove of Giant Sequoias

•	 South Entrance Garage (WA04601) – A 1934 garage constructed adjacent to the ranger

duplex and built in the Park Rustic style.

•	 South Entrance Stone Retaining Wall – A stone retaining wall at the rear of the ranger duplex,

designed to stabilize the cut in the hill slope north of the building.

•	 South Entrance Station Residence Road – A one­lane gravel road that leads from Wawona

Road past the east side of the ranger duplex to the entrance of the garage that was

constructed in 1934. The road has been altered by the addition of a loop road that branches

from this main access road to provide access to the front of the ranger duplex.

•	 South Entrance Station Fire Hydrant – A historic­period fire hydrant in the vicinity of the

Ranger Duplex that represents the only above­ground evidence of the South Entrance water

system in direct proximity to the buildings.

The contributing buildings and structures were all built during the same time period, in a similar

style, and possess a common association with development of the park’s South Entrance area. The

four historic buildings represent a unique style of Park Rustic architecture that was refined in the

national parks during the early years of the NPS, and primarily constructed with native materials

intended to blend harmoniously with their surroundings.

In addition to the contributing elements of the district, a lone giant sequoia, planted near the

northwest corner of the comfort station after completion of the South Entrance station in 1934, is

considered a character­defining element of the historic district landscape.

Circulation was an important landscape characteristic when the South Entrance station was

developed. However, circulation features have lost their historical integrity because of multiple

alterations to Wawona Road and the park entrance station infrastructure, and attributes of the

location are not considered character­defining. Although the T configuration of the intersection has

been retained, the number of lanes for Wawona Road has increased, and the widening of Wawona

Road resulted in the loss of some historical landscape elements, including the original concretecurbed traffic islands that directed the vehicles through the checking station and parking areas north 

and south of the comfort station. In general, the historic district retains integrity of location and

setting, and the buildings and structures possess integrity of materials, workmanship, and design

(NPS 2004c).

Environmental Consequences

Effects Assessment Methodology. Potential effects of the Mariposa Grove restoration project

alternatives on historic buildings, structures, and cultural landscapes were analyzed qualitatively

under Section 106 of the NHPA, in accordance with 36 Code of Federal Regulations (CFR)

800.5(a)(1) criteria for determining adverse effects, based on modifications that would be made to

character­defining features (i.e. characteristics that qualify the buildings, structures, or landscapes

for inclusion in the National Register).

The Secretary of the Interior’s Standards for the Treatment of Historic Properties with Guidelines for

Treatment of Cultural Landscapes (NPS 1996) include factors to consider, such as change and

continuity, use, and management and maintenance. Cultural landscapes are dynamic, and

preservation seeks to balance continuity with change. Current and proposed use can affect integrity

and current conditions. Maintenance and management of a cultural landscape can result in a

cumulative adverse effect, or well­conceived maintenance can sustain character­defining features

over a long period of time.

Final Environmental Impact Statement 3­112 October 2013

Chapter 3: Affected Environment and

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Cultural Resources: Historic Structures

Restoration of the Mariposa Grove of Giant Sequoias

National Historic Preservation Act Methods for Assessing Effect. The cultural resources

investigations the assessment of potential effects of the project alternatives were undertaken in

accordance with the NHPA Section 106 implementing regulations, 36 CFR 800, Protection of

Historic Properties. As amended, Section 106 of the NHPA requires federal agencies with either

direct or indirect jurisdiction over a proposed undertaking to take into account the effect of the

undertaking on historic properties. Pursuant to Director’s Order 12 (sections 2.14(6)(3), 6.2 F, and

6.3 F and Appendix 3); 40 CFR 1508.7, 1508.8, and 1508.27; and 36 CFR 800.8, effect intensity,

duration, context, and type, as they relate to historic properties, are determined using the criteria

established in 36 CFR Part 800. Per 36 CFR 800.5(a)(1), an adverse effect is found when an

undertaking may alter, directly or indirectly, any of the characteristics of a historic property that

qualify the property for inclusion in the National Register in a manner that would diminish the

integrity of the property's location, design, setting, materials, workmanship, feeling, or association. 

Compliance with Section 106 calls for implementation of a four­step process that includes

consultation with appropriate parties (36 CFR 800.3); identifying historic properties in the area of

potential effect of an undertaking (36 CFR 800.4); assessing adverse effects of the undertaking on

historic properties within the area of potential effect (36 CFR 800.5); and resolving any adverse

effects (36 CFR 800.6). These steps involve a range of activities, such as defining the undertaking,

identifying the proper consulting parties (e.g., SHPO and American Indian tribes and groups),

delineating the APE, identifying and evaluating properties in the APE, applying the effects criteria,

and resolving any adverse effects.

Under this four­step process, there are three possible effects determinations:

No Historic Properties Affected – A “no historic properties affected” determination indicates that

no historic properties are in the APE, or that there are historic properties in the APE, but the

undertaking would not alter the characteristics that qualify the historic property for inclusion in or

eligibility for the National Register.

No Adverse Effect – A “no adverse effect” determination indicates that there would be an effect on

the historic property by the undertaking, but the effect does not meet the criteria of adverse effect in

36 CFR 800.5(a)(1) and would not alter any of the characteristics that make the property eligible for

listing in the National Register in a manner that would diminish the integrity of the historic property.

Adverse Effect – An adverse effect indicates that the undertaking would alter, directly or indirectly,

any of the characteristics that qualify it for inclusion in the National Register in a manner that would

diminish the integrity of the property. Adverse effects may be resolved through development of a

project­specific Memorandum of Agreement (MOA) or a Programmatic Agreement among the

project proponent (NPS in this case), the SHPO, the Advisory Council on Historic Preservation

(ACHP), and other consulting or concurring parties, such as American Indian tribes (36 CFR 800.6).

The agreement would specify the mitigating actions that must be taken to resolve the adverse effects,

and the implementation and documentation protocols to be followed. The agreement must be

executed by all required signatories (i.e. consulting parties) before implementation of a proposed

action can be initiated.

Alternative 1: No Action

Under Alternative 1, current buildings and infrastructure, concessioner services (i.e. gift shop and

commercial tram) and maintenance, and park management would remain as is (see figures 2­1

through 2­4). No infrastructure improvement, ecological restoration, changes to visitor services, or

accessibility upgrades would be implemented.

Final Environmental Impact Statement 3­113 October 2013

Chapter 3: Affected Environment and

Environmental Consequences
       

               

   

         

               

                               

                         

                       

      

                     

                       

                           

              

                   

                                 

                       

                       

                           

                           

                             

              

                     

                             

                           

                     

                         

              

                               

                           

                             

                               

                         

                             

                                   

                    

                           

                         

                   

                           

                 

                       

                     

                           

                     

                               

                           

                             

                           

                            

Cultural Resources: Historic Structures

Restoration of the Mariposa Grove of Giant Sequoias

Operations­related Impacts. Effects on historic buildings, structures, and cultural landscapes

under current and predicted future operations could occur as a result of visitor use and routine

maintenance and repair. With continuing adherence to the Secretary of the Interior’s Standards for

the Treatment of Historic Properties, routine maintenance activities would cause no physical

destruction or damage.

Impact Significance and Determination of Effect. Routine maintenance and repairs to historic

buildings and structures within the Mariposa Grove and South Entrance Station historic districts

would be implemented in accordance with the Secretary of the Interior’s Standards for the Treatment

of Historic Properties to avoid adverse effects.

Conclusion. Under Alternative 1, existing structures, buildings, and infrastructure at the South 

Entrance and in the lower and upper portions of the Grove would continue to serve their respective

current functions and operations for the foreseeable future. No construction­related impacts would

occur. Continued routine maintenance and repair of the museum, ranger residence, comfort

stations, and other buildings and structures would be conducted in accordance with the Secretary of

the Interior’s Standards for the Treatment of Historic Properties to avoid adverse effects. Overall,

Alternative 1 is expected to have no adverse effect on the Mariposa Grove Historic District, South 

Entrance Historic District, and Mariposa Grove Museum.

Cumulative Impacts. The cumulative effects on historic structures discussed in this section are

based on an analysis of past, present, and reasonably foreseeable future actions in the Mariposa

Grove region in conjunction with the potential effects of Alternative 1 (No Action). The Mariposa

Grove Historic District (Determined Eligible, 2004), the Mariposa Grove Museum (National

Register, 1978), and the South Entrance Station Historic District (Determined Eligible 2004) are the

historic properties within the Mariposa Grove region.

A number of past projects took place in the area. In 1980, the Museum building went through 

significant repairs to replace logs and repair the structure and the building remains an interpretive

facility for the Mariposa Grove. Repair work for the septic system at South Entrance has been

ongoing since 2004. Work began in 2012 to relocate and replace the non­historic kiosks at the South 

Entrance. Within the Grove, new communications equipment was installed at Wawona Point in

2011. The NPS installed new interpretive and directional signs, starting in 2011. In addition, split­rail

wood fences were installed in high use areas to direct the public and protect the surface roots of the

giant sequoias. Appendix B describes these projects in more detail.

During project implementation of these past projects, the NPS avoided adverse effects, or otherwise

carried out appropriate mitigations to minimize effects on historic resources in accordance with the

park’s 1999 Programmatic Agreement (1999 Programmatic Agreement Between the National Park

Service at Yosemite, the California State Historic Preservation Officer, and the Advisory Council on

Historic Preservation Regarding Planning, Design Construction Operations and Maintenance, Yosemite

National Park, California). The Scenic Vista Management Plan/EA (2010), which is not fully

implemented, and the Wilderness Stewardship Plan (in progress) would implement actions

consistent with the standard four­step process outlined in 36 CFR Part 800, Protection of Historic

Properties, as described in the Effects Assessment Methodology for Historic Structures and

Landscapes described earlier in this section. In the future, the NPS will rehabilitate access to the

historic comfort stations at South Entrance and the upper Grove area to enhance accessibility. There

are no additional, reasonably foreseeable plans and projects that may contribute to an adverse effect

on historic properties in the Mariposa Grove and South Entrance area. Overall, past, present, and

future plans and projects would have no adverse effect on historic structures and landscapes.

Final Environmental Impact Statement 3­114 October 2013

Chapter 3: Affected Environment and

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Cultural Resources: Historic Structures

Restoration of the Mariposa Grove of Giant Sequoias

There would be no change in the treatment and management of historic buildings, structures, and

cultural landscape resources as a result of Alternative 1 (No Action). The effects from past, ongoing,

and potential future actions in combination with those of Alternative 1 would continue to result in

no adverse effects on historic structures and landscapes in the Mariposa Grove area.

Alternative 2: South Entrance Hub (Preferred Alternative)

Alternative 2, the preferred alternative, would

•	 remove the non­contributing commercial tram staging area and gift shop

•	 substantially reduce the non­contributing in­Grove parking, and relocate primary visitor

parking to the proposed transit hub at South Entrance

•	 discontinue commercial tram operations

•	 rehabilitate historic features, including repair of stone work at Wawona Point

•	 convert segments of the contributing road within the Grove to pedestrian trails

•	 rehabilitate a segment of the abandoned Washburn Road for use as a pedestrian trail

•	 construct a new trail segment from the picnic area to the lower Grove area

•	 make accessibility improvements to Grove trails

•	 improve path of travel accessibility to the upper Grove and South Entrance comfort stations

•	 install a new septic system/leach field at South Entrance

•	 refurbish the septic system and leach field in the upper Grove area

•	 construct a new septic/system leach field in the lower Grove area, or installation of a

wastewater pipeline, within the right of way of Mariposa Grove Road, from the lower Grove

area to the South Entrance leach field (may require a lift station near South Entrance)

•	 reconfigure the South Entrance station parking and other non­contributing infrastructure,

and reconfigure the Wawona Road/Mariposa Grove Road intersection.

Certain actions under Alternative 2 would rehabilitate historic structures or features that contribute

to the significance of the South Entrance Station and Mariposa Grove historic districts. The

Secretary of the Interior’s Standards for the Treatment of Historic Properties define rehabilitation as

“the act or process of making possible a compatible use for a property through repair, alterations,

and additions while preserving those portions or features which convey its historical, cultural, or

architectural values.

Historic rehabilitation and ecological restoration at Wawona Point would be components of this

alternative. Historic rehabilitation of the Wawona Point overlook would include repointing historic

rockwork, rebuilding historic steps, restoring historic pathways, replacing existing railing with codecompliant safety railing, removing excess pavement, and revegetation that could include screening of

incompatible, modern communications equipment.

Paths of travel to the historic comfort stations at the upper Grove area and at South Entrance would

be improved to better meet ABAAS requirements. Any modification of the paths of travel would be

completed in a historically compatible manner that would not detract from the historic setting or

feeling. Rehabilitation of the historic comfort stations, which is not included in this project, may be

Final Environmental Impact Statement 3­115 October 2013

Chapter 3: Affected Environment and

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Cultural Resources: Historic Structures

Restoration of the Mariposa Grove of Giant Sequoias

undertaken in the future as a separate project as funding becomes available and would be addressed

through a separate compliance process, as needed.

Ecological restoration actions such as improvement of hydrologic flow through road and trail

modifications, repair and replacement of culverts, and replacement of leaking water lines; projectspecific prescribed fire and hazardous fuel reduction treatments; reclamation of giant sequoia habitat

through reduction of both non­contributing and contributing hardscape features; and soil

decompaction; would be components of this alternative. Actions that remove incompatible buildings

and structures from the lower part of Mariposa Grove and ecologically restore giant sequoia habitat

would serve to restore giant sequoia groves that contribute to the Mariposa Grove Historic District.

Proposed modifications to the extension of the Mariposa Grove Road within the Grove, which is a

circulation feature that contributes to the Mariposa Grove Historic District, would alter the historic

design, materials, and workmanship of the historic paved road. These modifications include road

realignment and installation of a new drainage crossing structure at the Sentinels, replacement of

asphalt pavement with a hardened permeable surface, narrowing of the existing roadbed, removal of

a road segment from wetlands in the lower Grove area, and conversion of road segments to

pedestrian trails.

The parking lot to be relocated from the lower Grove area to South Entrance and the new visitor

services would overlap the eastern boundary of the South Entrance Station Historic District, and

would include modifications to Mariposa Grove Road for ingress/egress into the new parking facility

and a new shuttle stop, and conversion of the existing overflow parking lot for bus turn­around. A

new roundabout could be constructed west of the contributing office (former check station)

building, replacing the existing T­intersection situated east of the office at the intersection of

Wawona Road and Mariposa Grove Road. This intersection reconfiguration would be implemented

if, based on monitoring of intersection capacity following relocation of the entrance kiosks, which 

was recently completed under a separate project, traffic volumes and flow result in back­ups to the

new kiosks on a regular basis.

Construction­ and Restoration­related Impacts. Actions under Alternative 2 that have the

potential to affect historic buildings, structures, and cultural landscapes, and the nature of the

effects, are summarized as follows:

1.	 Reconfiguration of Intersection at South Entrance. The existing T­intersection of Wawona

Road and Mariposa Grove Road could be reconfigured and replaced by a roundabout, if

future traffic conditions warrant. The existing intersection is east of the South Entrance

office building; the proposed roundabout would be situated west of the office building. The

office building, which is a contributing element of the South Entrance Historic District,

would not be affected by an intersection reconfiguration.

Reconfiguration of the intersection would affect the setting and intersection design within

the South Entrance Historic District. However, the historic circulation features in this area of

the district are no longer extant, and the proposed changes represent minor alterations to the

setting of the district overall. The redesign of the circulation features would not have an

adverse effect on the historic district. In addition, the historical integrity of the office

building would not be affected because no alterations to this contributing building would

occur as a result of the road alterations. Therefore, there would be no adverse effect on the

South Entrance Station Historic District from the proposed intersection reconfiguration.

Final Environmental Impact Statement 3­116 October 2013

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Cultural Resources: Historic Structures

Restoration of the Mariposa Grove of Giant Sequoias

2.	 Construction of South Entrance Hub. The new transit hub would include construction of a

295­space parking lot, a shuttle boarding and tour bus transfer area (including turnouts from

Mariposa Grove Road), a bus turn­around area, visitor contact area, accessible comfort

station and septic system/leach field, and a new pedestrian trailhead on the historic

Washburn Wagon Road. Construction of the transit hub at South Entrance would occur

partially within the southeastern part of the South Entrance Station Historic District

(figure 3­24), and within the Mariposa Grove Historic District (i.e. at new turnouts from

Mariposa Grove Road, a contributing element of that district).

The modification of roads within the historic districts would affect the district settings, but it

would not introduce a new use to the area. The new parking and visitor facilities would be

constructed outside the boundaries of both the South Entrance and Mariposa Grove historic

districts. The South Entrance vicinity currently is heavily used for parking, shuttle boarding,

restrooms, and visitor contact. The introduction of new infrastructure would not require the

removal of any of the contributing elements of the South Entrance Historic District, such as

the historic buildings and structures, and the turn­offs would not alter the integrity of

Mariposa Grove Road location, design, setting, materials, workmanship, feeling, or

association. The visual effect of the new transit hub on the South Entrance setting would be

minimal and, therefore, construction of a South Entrance Hub and reconfiguration of the

road intersection under Alternative 2 would have no adverse effect on the Mariposa Grove

or South Entrance Station historic districts. The effects of rehabilitating the Washburn

Wagon Road for use as a trail are also assessed in the Archeology subsection of this chapter

of the Mariposa Grove FEIS.

3.	 Removal/Replacement of Non­Historic Buildings and Infrastructure in the Lower Grove Area.

The parking lot, vault toilets, gift shop, and tram staging area are all non­contributing

features within the Mariposa Grove Historic District. All of these features would be removed

from the lower Grove area, and a smaller, accessible comfort station, a septic system and

leach field (or a new sewer line from the lower Grove area to the South Entrance leach field

within the Mariposa Grove Road right of way), a shuttle boarding/off­season parking area,

and a trailhead for new accessible trails would be constructed. These actions would occur

within the boundaries of the Mariposa Grove Historic District. Removal of incompatible and

non­contributing buildings, structures, and hardscape, and replacement with restored lower

Grove giant sequoia habitat and new, historically compatible, less intrusive comfort station

and infrastructure are expected to affect the setting of the lower Grove portion of the

Mariposa Grove Historic District. However, as these actions would reestablish a level and

types of development in the lower Grove area closer to the level of development during the

period of significance (i.e. roads, trails, limited parking, and comfort station), they may be

considered to have no adverse effect on the district. The potential construction of a new

wastewater line within the Mariposa Grove Road right of way from the lower Grove area to

South Entrance would be below grade, and would have no adverse effect on the historic

district.

4.	 Conversion of Paved Vehicular Road in Lower Grove Area to an Accessible Trail. An ABAAScompliant trail would be constructed within the boundaries of the Mariposa Grove Historic

District. It may be constructed as an at­grade trail with sections of boardwalk, or entirely as a

boardwalk. Where the trail crosses the lower Grove area wetlands along the historic road,

the road bed fill would be removed to allow for wetland restoration. An existing rock

masonry wall would be removed to construct the boardwalk. Boardwalk construction would

place the travel surface higher than the existing road surface, and would include redirecting

vehicular traffic (e.g., service vehicles) onto a new bypass road around the lower Grove area.

The bypass route would follow an abandoned road alignment. The effect from introduction

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Cultural Resources: Historic Structures

Restoration of the Mariposa Grove of Giant Sequoias

of a boardwalk as well as the removal of a segment of the road grade from the wetlands,

would affect the integrity of design, materials, and feeling of this portion of the historic

roadway. Therefore, this action would have an adverse effect on the Mariposa Grove

Historic District.

5.	 Rehabilitation/Construction of a Pedestrian Trail from South Entrance to the Lower Mariposa

Grove Area. A segment of the abandoned historic Washburn Wagon Road between the new

South Entrance Hub and the existing picnic area along Mariposa Grove Road would be

rehabilitated for use as a pedestrian trail, and a new trail segment would be constructed south 

of Mariposa Grove Road from the picnic area to the lower Grove area. The path of the new

trail would lie partially within the boundaries of Mariposa Grove Historic District, but would

not affect the historic integrity of contributing district features or introduce a new use to the

district. The visual effect on the South Entrance Station and Mariposa Grove historic district

settings would be minimal, and therefore this action would have no adverse effect on either

historic district. The effects of rehabilitating the Washburn Wagon Road for use as a trail are

also assessed in the Archeology subsection of this chapter of the Mariposa Grove FEIS.

6.	 Engineered Hydrology and Road Improvements. Road and drainage modifications within the

Mariposa Grove Historic District would be undertaken under Alternative 2 to restore natural

hydrologic flows as part of the ecological restoration of giant sequoia habitat. Actions and

their potential effects on the historic district are summarized as follows:

a.	 Culvert Repairs and Replacement. The culvert repairs and replacement would occur

within the boundaries of the Mariposa Grove Historic District. The culverts are not

contributing elements of the Mariposa Grove Historic District and are difficult to

associate with a particular time within the district period of significance, having been

constructed and reconstructed as needed. In general, there are about 60 culverts

along the road through the Grove that could be repaired or replaced. Some of the

culverts are at the bases of giant sequoias. The culverts vary in construction style, but

typically are riprap covered with dirt in rock channels, some with minor rock

headwalls. The masonry headwalls are of standard, very simple construction that

does not reflect significant engineering design or artistic construction, nor exemplify

a design unique to the Civilian Conservation Corps period. Culvert repairs and

replacement would be conducted in accordance with the Secretary’s Standards for

Rehabilitation and would not alter the integrity of the contributing road’s location,

design, materials, workmanship, feeling, or association. Therefore, culvert repair or

replacement would have no adverse effect on the Mariposa Grove Historic District

or its contributing features.

b.	 Outsloping of Road and Trail Segments. Outsloping would occur within the

boundaries of the Mariposa Grove Historic District along selected contributing and

non­contributing trails as well as those portions of the Mariposa Grove Road that

function primarily as trails. Outsloping would require regrading, and would result in

micro­changes in the road elevation and cross­section, but would not significantly

alter the location, design, materials, workmanship, feeling, or association. Therefore,

outsloping would have no adverse effect.

7.	 Minor Road Realignment in Lower Mariposa Grove Area. Mariposa Grove Road would be

slightly realigned to accommodate construction of a new septic system and leach field, a

relocated shuttle passenger drop­off /off­season parking area, comfort station, and accessible

trailhead. The alterations to the road alignment would occur within the boundaries of the

Mariposa Grove Historic District, and the road is a contributing element of the district. The

shift in the alignment would affect the design of the roadway, but the changes would be

minor. The character­defining circulation patterns of the Mariposa Grove Historic District

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Cultural Resources: Historic Structures

Restoration of the Mariposa Grove of Giant Sequoias

would be retained and the road’s integrity of materials, workmanship, feeling, and

association would be retained. Therefore, this road realignment would have no adverse

effect on the district or its contributing elements.

8.	 Relocation of Passenger Drop­Off /Off­Season Parking Area in Lower Mariposa Grove Area.

The relocation of passenger drop­off /off­season parking area would occur within the

boundaries of the Mariposa Grove Historic District. Removal of the non­contributing

existing shuttle/bus parking area and gift shop and replacement with restored lower Grove

habitat, and relocation of a historically compatible, less intrusive drop­off /parking area to

the northeast would occur under this alternative. Because of the addition of a new noncontributing circulation features within the pedestrian passenger drop­off area, an adverse

effect is expected on the setting of the lower Grove portion of the Mariposa Grove Historic

District.

9.	 Conversion of North Portion of Parking Lot and an Old Road Alignment in Lower Mariposa

Grove to New Grove Bypass Road. The north portion of the existing lower Grove area 115­

space parking lot would be converted to a new hardened, narrow Grove bypass road that

would connect with an old, non­contributing road alignment, and subsequently merge with 

the existing Mariposa Grove Road to the northeast of the lower Mariposa Grove area. This

wetland bypass would be used by accessible transport and service vehicles. The conversion

of the portion of the parking lot and reuse of an old road alignment would occur within the

boundaries of the Mariposa Grove Historic District; however, the parking lot and abandoned

road are not contributing features of the district. Removal of non­contributing hardscape,

and replacement with restored lower Grove giant sequoia habitat and restored wetlands, and

a new, historically compatible, less intrusive road that follows an abandoned road trace, is

expected to affect the setting of the lower Grove portion of the Mariposa Grove Historic

District, but would have no adverse effect on the district or its contributing elements.

10. Major Road Realignment. Mariposa Grove Road would be realigned to reduce a sharp curve

in the vicinity of the Sentinels at the approach to the lower Mariposa Grove area, and a new

vehicular crossing structure (a box culvert or bridge) would be constructed to span the

intermittent drainage at that location. These actions would improve safety, protect giant

sequoias from erosion in the drainage, which could threaten their stability and long­term

survival, and increase the roadway capacity for tour buses. The current road curve segment

would be topographically and hydrological restored, eliminating the road prism. The

realignment and drainage crossing construction would occur within the boundaries of the

Mariposa Grove Historic District, and the Mariposa Grove Road and the giant sequoias are

contributing elements of the district. This major realignment, eradication of the road prism,

and addition of a new structure where there historically was none would affect the road’s

aspects of integrity including design, materials,, and feeling in the vicinity of the Grove

entrance. Straightening the curve and introduction of a crossing structure would alter the

sense of arrival into the lower Grove area, and the visitors’ first view of big trees: the three

giant sequoias known as the Sentinels. Therefore, this action would have an adverse effect

on the historic district.

11. Conversion of Paved Road to Accessible Trail in the Wetland of the Lower Grove Area. The 10­

to 20­foot­wide, asphalt­paved Mariposa Grove Road in the wetland area in the vicinity of

the Fallen Monarch tree would be converted to an 8­ to 10­foot­wide ABAAS­compliant

accessible, hardened loop trail in the ecologically restored lower Grove area. The affected

segments of this historic roadway are within the boundaries of the Mariposa Grove Historic

District, and the road is a contributor to that district. The proposed conversion may require

grade modifications and may introduce a boardwalk to reduce impacts on sensitive wetlands,

but the road prism would largely be retained. An exception would occur where the road

Final Environmental Impact Statement 3­119 October 2013

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Cultural Resources: Historic Structures

Restoration of the Mariposa Grove of Giant Sequoias

crosses the wetlands; for that segment, the road bed and fill including a stone headwall where

the creek crosses under the road would be removed to allow the wetland to be restored. To

attain ABAAS compliance, the historic road alignment also may be altered to incorporate the

use of switchbacks and curves not present in the existing road design. Narrowing,

introduction of a boardwalk, removal of road materials from the wetland, and changes in

alignment would result in a loss of integrity of historic road design and materials. Although

the removal of the asphalt paving and replacement with a hardened surface in itself would

not necessarily result in an adverse effect, the conversion of the roadway into a ABAAS

compliant trail, l would likely alter the feeling and design in such a way that it would no

longer feel or appear as a historic road. Therefore, conversion of this portion of the historic

road into an ABAAS compliant pedestrian trails and boardwalks would have an adverse

effect on the historic district.

12. Conversion of Segment of Mariposa Grove Road and Loop Road between Grizzly Giant and

Mariposa Grove Museum, and Wawona Point to a Hardened Trail. The segment of Mariposa

Grove Road between Grizzly Giant and Wawona Point, including a short spur to the

Mariposa Grove Museum and nearby comfort station, would retain the historic road prisms.

However, where possible, the travel­way would be narrowed to a minimum width of 11 feet,

asphalt­paved surfaces may be converted to hardened surface, disturbed areas along the road

would be allowed to revert to natural conditions, and existing pullouts would be assessed

and removed where unnecessary. The segment of Mariposa Grove Road between Grizzly

Giant and the museum, and the Wawona Point road, are within the boundaries of the

Mariposa Grove Historic District and are contributors to that district. The integrity of

location, setting, and association would be retained, and resurfacing would not result in an

adverse effect. The character­defining circulation patterns of the Mariposa Grove Historic

District would be retained, and these segments would continue to convey their feeling as

historic roads. Therefore, proposed modification of these historic roadway segments under

Alternative 2 would have no adverse effect on the historic district or its contributing

elements.

13. Conversion of the Loop Road in the Upper Grove Area to a Pedestrian Trail. The portion of the

loop road extending from the restrooms in the upper Grove area to the T­intersection with 

the road extending to Wawona Point, would be modified from a paved, one­way road (varies

between 12 and­ 20 feet wide) to a pedestrian trail (from 4 to 6 feet wide). Previously

disturbed road areas would be revegetated. The loop road is within the boundaries of the

Mariposa Grove Historic District, and is a contributing road circulation feature. Although 

the conversion or the road into a trail would retain the historic road prism, the road would

no longer appear as such because of the combination of the removal of the asphalt surfacing,

the significant reduction of its width into a dirt trail, and the revegetation of the disturbed

areas along the trail. As a result, this loop road would no longer convey its feeling as a

historic road. Therefore, this action would have an adverse effect on the historic circulation

system within the Mariposa Grove Historic District.

14. Ecological Restoration of Road Margins. The road margins of Mariposa Grove Road between

the lower Grove area and Grizzly Giant, the Mariposa Grove Road and loop road between

Grizzly Giant and the Mariposa Grove Museum, the Wawona Point spur, and the east and

south sections of a paved road loop that is being converted to pedestrian trail in the upper

Grove area, may be modified to support revegetation. The historic road prism (cut, fill, and

road bed) would largely be retained, but where narrowing occurs, road margins would be

revegetated using native forbs, grasses and low shrubs to retain views into the adjacent

forest, and thereby maintaining the character of the 1934 roadside landscape design.

Final Environmental Impact Statement 3­120 October 2013

Chapter 3: Affected Environment and

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Cultural Resources: Historic Structures

Restoration of the Mariposa Grove of Giant Sequoias

Therefore, conversion of the historic roadway margins would have no adverse effect on

character­defining roadside landscaping within the Mariposa Grove Historic District.

15. Modify Path of Travel to Historic Comfort Station at South Entrance. The historic comfort

station at South Entrance is a contributor to the South Entrance Historic District. The path 

of travel to this structure would be upgraded to improve accessibility in compliance with 

ABAAS as part of this project. The comfort station is not proposed for rehabilitation at this

time, but future accessibility improvement may be implemented under a separate future

project as funds become available. The path of travel is not a contributing element of the

historic district. Path­of­travel improvements could include minor grading, realignment to

reduce grades, resurfacing with hardening materials, and proving ramping at existing curbs

or other obstacles. Comfort station path­of­travel accessibility modifications would be

completed using historically compatible design and materials, and would follow existing

pathways to the extent practicable. These improvements would not alter location,

workmanship, design, or association of the comfort station or the South Entrance Station

Historic District. Realignment of the paths of travel could affect the setting and feeling of the

district, but these actions would have no adverse effect on the district.

16. Septic System/Leach Field Improvements at South Entrance and in the Upper Grove Area. The

septic system/leach field at South Entrance, which serves the historic ranger duplex and the

historic comfort station, and the septic system/leach field in the upper Grove area, which 

serves the historic comfort station, would be improved. The South Entrance septic system

would be relocated and expanded to accommodate the new visitor services at the South 

Entrance hub. The upper Grove system, which exceeds its service life, would be replaced

pending geotechnical analysis. Neither of these systems is a contributor to the respective

historic districts. These improvements would be conducted in a manner that would avoid

impact on character­defining or contributing elements of the districts, and would therefore

have no adverse effect on Mariposa Grove or South Entrance Station historic districts.

17. Rehabilitation of Wawona Point Overlook. Under Alternative 2, the masonry structures at the

overlook would be rehabilitated in accordance with the Secretary of the Interior’s treatment

standards, which define rehabilitation to allow incorporation of other defined treatments,

including preservation and restoration. Stone masonry would be restored by repointing and

stabilization of side walls. Rehabilitation actions would include installation of compatible,

code­compliant handrails. Landscape rehabilitation would involve ecological restoration of

an abandoned parking area with low­growing plants that will retain the spatial characteristics

of the former parking area, and revegetation that could include screening of incompatible,

modern communications equipment. Historic overlook features would be stabilized and

preserved to the extent possible. These rehabilitation actions would have no adverse effect

on the historic features of Wawona Point, located within the Mariposa Grove Historic

District.

18. Change in Function of Mariposa Grove Museum. Alternative 2 would include a possible

change in the current use of the building as the Grove’s primary interpretive center to

another compatible use. Physical alteration of the building is not planned under this project,

and any new use would be compatible with the historic use and rustic character of the

building. Should alternations to the building become necessary once a use is determined,

further compliance would be completed as a separate project. Therefore, there would be no

adverse effect on the Mariposa Grove Museum or the Mariposa Grove Historic District

under Alternative 2.

19. Water Supply System Repairs and Modifications. The water supply storage tank and

chlorination unit are within the Mariposa Grove Historic District, and a water distribution

pipeline traverses the Mariposa Grove Historic District at its upper end, and terminates at

Final Environmental Impact Statement 3­121 October 2013

Chapter 3: Affected Environment and

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Cultural Resources: Historic Structures

Restoration of the Mariposa Grove of Giant Sequoias

the South Entrance Station Historic District, where it serves facilities at South Entrance.

These water storage, treatment, and distribution systems are not contributing elements of

either historic district. The water tank and chlorinator are to be relocated to a new location

along the access road leading to Wawona Point as part of this action. The new location would

be chosen so that none of the nearby contributing elements of the Mariposa Grove Historic

District would be affected. The extent of water pipeline repairs needed and methods for

repairs are not yet determined, but the repairs are not be expected to require removal,

realignment, or major alteration of any contributing elements of the Mariposa Grove

Historic District, the Mariposa Grove Museum, or the South Entrance Station Historic

District. Any effects on the setting of the districts caused by repairs to the pipeline would be

temporary, and would not be adverse. The new buried water tank at the South Entrance

would not impact the road, which is a contributing feature. Therefore, the water system

modifications would have no adverse effect on historic properties.

20. Structural Sustainability Improvements to Existing Infrastructure. The NPS promotes the

recognition of historic preservation as the best sustainable practice for the historic built

environment. The retention of historic buildings, structures, and cultural landscapes

conserves the natural, labor, and energy resources expended in the original construction and

prior maintenance of these cultural resources, and minimizes the need for additional

investment of raw materials and labor to replace such resources with new construction. The

National Park Service Guiding Principles of Sustainable Design (NPS 1993) are primarily

intended to be applied to new construction. Many of these sustainability guidelines, which 

call for designs such as re­orientating buildings or constructing vestibules, are not proposed

for any of the contributing buildings of the Mariposa Grove and South Entrance Station

historic districts or the Mariposa Grove Museum. Therefore, there are no historic properties

affected by sustainability upgrades under Alternative 2.

21. Construction Staging Areas. Construction staging areas needed under Alternative 2 may be

located within or adjacent to the South Entrance Station and Mariposa Grove historic

districts, but staging areas would be sited to avoid historic features and would be temporary.

These temporary staging areas are expected to affect both historic districts, but the effects

would not be adverse. Therefore, there would no adverse effect on the historic districts

from construction staging activities.

Impact Significance and Determination of Effect. Implementation of Alternative 2 is expected to

have an adverse effect on the Mariposa Grove Historic District, predominantly through proposed

modifications to the Mariposa Grove Road, which is proposed as part of the ecological restoration of

giant sequoia and wetland habitat measures and accessibility improvements under this alternative.

Although there would be adverse effects to the historic district as a result of this alternative, the

combined actions do not result in a loss of integrity of the historic district as a whole. Ensuring the

long­term health of the Grove remains a primary management objective for both the cultural and

natural resources in all the action alternatives. The NPS is firmly committed to the responsible

management of historic properties that may be affected by the proposed engineered hydrologic and

road improvements, and acknowledges the delicate balance required to ecologically restore the

Mariposa Grove of Giant Sequoias and to preserve the historic properties, of which the giant

sequoias themselves are a key contributing component.

Alternative 2 would have no adverse effect on the South Entrance Station Historic District. The

majority of improvements for the South Entrance Hub would be located outside the district. The

accessibility improvements to the path of travel to the historic comfort station and reconfiguration of

the Wawona Road/Mariposa Grove Road intersection would minimally affect the setting and feeling

Final Environmental Impact Statement 3­122 October 2013

Chapter 3: Affected Environment and

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Cultural Resources: Historic Structures

Restoration of the Mariposa Grove of Giant Sequoias

of the historic district, but would not alter the integrity of contributing or character­defining features

of the South Entrance Historic District.

All actions under Alternative 2 that would affect contributing historic structures or cultural

landscape features and that are necessary either to ensure long­term survival of the giant sequoias or

to meet current accessibility or safety codes would, to the extent practicable, be designed in

accordance with the Secretary of the Interior’s Standards for the Treatment of Historic Properties.

When such design is not feasible, the park would choose the least invasive/disruptive option, and

consult with SHPO to develop measures to resolve adverse effects.

Operations­related Impacts. No adverse effects on historic buildings, structures, or cultural

landscapes are anticipated from park or concessioner operations under Alternative 2, as operating

activities would not significantly alter, directly or indirectly, any of the characteristics of the historic

buildings, structures, and cultural landscapes that qualify them for inclusion in the National Register

in a manner that would diminish the integrity of the properties’ location, design, setting, materials,

workmanship, feeling, or association. Alternative 2 would decrease incompatible uses and

operational stress on the Mariposa Grove Historic District through elimination of the gift shop and

commercial tram service, relocation of most transit facilities to South Entrance, and substantial

curtailment of vehicular access to and through the Grove.

Modifications to non­contributing South Entrance station infrastructure (existing overflow parking

and road intersection design) and relocation of Mariposa Grove visitor parking to the South 

Entrance area, would be compatible with historic circulation patterns and 1934 parking patterns in

the South Entrance Station Historic District. These improvements would alleviate traffic congestion

and reduce traffic hazards associated with future anticipated visitor access to Yosemite National

Park and the Mariposa Grove of Giant Sequoias. Operations under Alternative 2 would result in no

physical destruction or damage; physical alterations inconsistent with the Secretary of the Interior’s

Standards for the Treatment of Historic Properties; disposal of the property; incompatible change in

the character of the historic properties’ use or setting; introduction of incompatible visual,

atmospheric, or auditory elements; or neglect or deterioration that would constitute an adverse

effect on the Mariposa Grove or South Entrance Station historic districts. The management and

routine maintenance and repair of historic buildings, structures, and cultural landscape features

would continue to be implemented in keeping with the Secretary of the Interior’s Standards for the

Treatment of Historic Properties.

Impact Significance and Determination of Effect. Operation of Alternative 2 would have no

adverse effect on historic buildings, structures, or cultural landscapes.

Conclusion. Under Alternative 2, proposed ecological restoration and code­compliance actions

would adversely affect contributing elements of the Mariposa Grove and the South Entrance Station

historic districts. The actions would have no adverse effect on the Mariposa Grove Museum. It is

expected that the following actions would have no adverse effect to historic properties:

•	 removal of the lower Grove area non­historic buildings and infrastructure, including the gift

shop, comfort station, parking lot, and tram staging area

•	 possible installation of a wastewater pipeline within the Mariposa Grove Road right of way

from the lower Grove comfort station to the South Entrance leach field (in lieu of a new

leach field in the lower Grove area)

•	 engineered hydrology and road improvements including repair and replacement of culverts,

outsloping, minor road alignment shifts, removal of road surface but retention of road prisms

Final Environmental Impact Statement 3­123 October 2013

Chapter 3: Affected Environment and

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Cultural Resources: Historic Structures

Restoration of the Mariposa Grove of Giant Sequoias

•	 refurbishing of the upper Grove area septic system/leach field

•	 rehabilitation of Wawona Point overlook

•	 repurposing of the Mariposa Grove Museum

•	 modifications to/repair of the water supply system

•	 construction of new South Entrance Hub infrastructure, including new leach field, parking,

bus turn­around area, Mariposa Grove Road turnouts, accessible comfort station, and

improved path of travel to the historic comfort station

•	 reconfiguration of the T­intersection to a traffic circle at the South Entrance

•	 rehabilitation of Washburn Wagon Road (also see Archeology section in this chapter) and

construction of a new trail segment from the picnic area to the lower Grove area

•	 temporary construction staging areas within Mariposa Grove and South Entrance Station

historic districts

However, the following actions would constitute an adverse effect on the Mariposa Grove Historic

District:

•	 relocation of Mariposa Grove out of the wetland in the lower Grove area, removal of the

road fill within the wetland, and installation of a new ABAAS­compliant trail minimizing

impacts on the wetland including the use of boardwalks, where needed.

•	 relocation of a smaller parking area and comfort station, and creation of a shuttle turnaround

area to the northeast of the existing bus parking area

•	 engineered hydrology and roadway improvements that involve major road alignment shifts,

such as straightening of the curve in Mariposa Grove Road near the Sentinels, and

construction of a new Mariposa Grove Road drainage­crossing structure at the Sentinels

•	 narrowing of historic roads to less than 8 feet wide along the upper Grove loop road

•	 eradication of road prisms for topographic and hydrological or wetlands restoration (e.g., at

the Sentinels and in the lower Grove wetlands).

Adverse effects on historic properties as a result of implementation of this project alternative would

be resolved through consultation with the California SHPO in accordance with the NHPA

implementing regulations at 36 CFR Part 800, and implemented through a project­specific MOA to

be refined in consultation with the SHPO, ACHP, and associated American Indian tribes and groups.

The draft MOA is in Appendix G. The final agreement will be signed before the Record of Decision

is completed and will be included as a part of the decision document for this project.

Operation of South Entrance and Mariposa Grove under Alternative 2 would have no adverse effect

on the Mariposa Grove Historic District or the South Entrance Station Historic District.

Cumulative Impacts. The regional past, present, and reasonably foreseeable projects affecting

historic structures and landscapes would be the same as those under Alternative 1 (No Action)—no

adverse effects on historic structures and landscapes in the Mariposa Grove area. Under

Alternative 2, some proposed actions would affect historic properties, such as demolition of nonhistoric buildings in the lower Grove area, but the effects would not be adverse. Some actions would

constitute an adverse effect on the Mariposa Grove Historic District, such as the conversion of the

Mariposa Grove Road to an ABAAS­compliant loop trail. Alternative 2 would not have an adverse

Final Environmental Impact Statement 3­124 October 2013

Chapter 3: Affected Environment and

Environmental Consequences
       

               

   

         

                           

                         

                       

                                   

                           

                   

                       

                 

        

          

         

                       

             

                      

                             

           

                                 

       

                               

                       

    

                         

                             

                                 

              

                     

                               

                       

                         

                                

                           

                           

                             

                         

                      

             

                           

                           

                

Cultural Resources: Historic Structures

Restoration of the Mariposa Grove of Giant Sequoias

effect on the South Entrance Station Historic District because most actions are either outside the

boundary, or involve updating circulation features which were not identified as contributing in the

2004 Determination of Eligibility. The Mariposa Grove Museum would have no physical changes

made to the structure as a result of this alternative. The cumulative effect of past, present, and future

projects (no adverse effect), in conjunction with of Alternative 4 (adverse effect), would be an

adverse effect on historic properties. Adverse effects would be resolved through consultation with 

the California SHPO and traditionally associated American Indian tribes and groups in accordance

with 36 CFR Part 800 (NHPA implementing regulations) and implemented through a projectspecific MOA (Appendix G).

Alternative 3: Grizzly Giant Hub

Implementation of Alternative 3 would:

•	 remove the non­contributing gift shop and tram staging area/tram operations from Mariposa

Grove

•	 remove parking lot from lower Grove area

•	 reduce the number of vault toilets in the lower Grove area

•	 convert the segment of the historic paved road between the lower Grove area and Grizzly

Giant in to a pedestrian trail

•	 Remove a segment of the Mariposa Grove Road at the entrance to the lower Grove area and

ecologically restore the area.

•	 build a new two­way, paved bypass road, including two new bridges, to a new visitor arrival

area with parking and other visitor amenities located outside giant sequoia habitat near the

Grizzly Giant

The Grove and South Entrance water supply system would be modified as described for

Alternative 2, and the upper Grove leach field would be refurbished. New comfort stations at the

lower Grove area and the new Grizzly Giant hub would use vault toilets, and would not require

development of additional septic systems or leach fields.

Numerous other historic rehabilitation and ecological restoration actions within the Mariposa

Grove Historic District would be similar in scope to like actions described for Alternative 2. These

would include rehabilitation of the Wawona Point overlook, and habitat restoration measures

(including road and trail improvements to restore hydrologic flows. Development of accessible trails

in the lower and mid­Grove areas would be less extensive than is proposed under Alternative 2.

Alternative 3 would not modify facilities at South Entrance. The existing South Entrance parking lot,

shuttle stop, leach field, and intersection of Wawona Road and Mariposa Grove Road would be

retained, as would all four of the historic buildings that contribute to the South Entrance Station

Historic District (ranger duplex and associated garage, office building, and comfort station). There

would be no adverse effect at the South Entrance under Alternative 3.

Construction­ and Restoration­related Impacts. Construction and ecological restoration actions

proposed under Alternative 3 are expected to affect contributing elements of the Mariposa Grove

Historic District. Actions under Alternative 3 that have the potential to affect historic buildings,

structures, and cultural landscape features include the following:

Final Environmental Impact Statement 3­125 October 2013

Chapter 3: Affected Environment and

Environmental Consequences
       

               

   

         

                   

                         

                         

                       

                           

                         

                         

                                   

                       

                           

                               

                             

                         

                               

                           

                         

                       

                             

                               

                       

                       

                             

                             

                         

                       

                       

                                 

                     

                           

      

                       

                           

                               

                           

                       

                                   

                       

                             

                           

                     

                           

                   

                   

                     

                         

                     

                   

                 

Cultural Resources: Historic Structures

Restoration of the Mariposa Grove of Giant Sequoias

1.	 Removal/Replacement of Non­Contributing Buildings and Infrastructure in the Lower Grove

Area. The non­historic gift shop, tram staging area, parking lot, and comfort station in the

lower part of Mariposa Grove would be demolished and removed. A new, 10­space,

dedicated ABAAS­compliant parking lot, a new accessible 2­vault comfort station, and a new

trail head would be constructed, largely in the footprint of previous infrastructure at the

lower Grove area. Construction would occur within the boundaries of the Mariposa Grove

Historic District. While the introduction of new infrastructure in the historic district would

affect the lower Grove setting of the historic district, it would not introduce a new use to the

area, which is already heavily used for parking, shuttle boarding, restrooms, and visitor

contacts, or remove any contributing elements of the historic district, and would restore the

natural setting of the lower Grove area to a more historic condition. As these actions would

reestablish a level and types of development in the lower Grove area more similar to those

present during the period of significance (i.e. roads, trails, limited parking, and comfort

station), they may be considered to have no adverse effect on the district. The visual effect

on the South Entrance setting would be minimal and, therefore, there would be no adverse

effect.

2.	 Construction of New Grizzly Giant Bypass Road. Under Alternative 3, the Mariposa Grove

Road approach to the lower Mariposa Grove area, including the curve at the Sentinels,

would be removed and the area ecologically restored, and a new two­way, paved road would

be constructed to bypass the lower Grove area and to serve the new Grizzly Giant Hub. This

removal, ecological restoration, and new road and bridge construction would occur within

the Mariposa Grove Historic District. Although construction of the new bypass road would

not directly affect contributing elements of the district, it would introduce a new roadway in

the district that would indirectly affect the integrity of setting, feeling, and association of the

district. Removal and ecological restoration of the historic entry road segment of Mariposa

Grove Road would directly affect the contributing historic roadway, and eliminate the

character­defining historic first view of giant sequoias on the approach to Mariposa Grove

(i.e. view of the Sentinels), thereby altering the sense of arrival at the Grove and affecting the

integrity of location, material, workmanship, association, and feeling of the Mariposa Grove

Road. These actions under Alternative 3 would have an adverse effect on the Mariposa

Grove Historic District.

3.	 Construction of New Grizzly Giant Hub. Construction of the new hub buildings and

infrastructure, including a visitor parking lot, bus parking, a visitor contact area, a trailhead

for a new accessible Grizzly Giant trail, a new comfort station, and removal of the existing

vault toilet and the commercial tram turnout, would occur within the boundaries of the

Mariposa Grove Historic District. The introduction of new infrastructure in the historic

district would affect the setting of the district, but it would not introduce a new use to the

area, which is already heavily used for parking, shuttle boarding, restrooms, and visitor

contact, or remove any of the contributing elements of the historic district. Due to its

location outside of giant sequoia habitat in a previously disturbed area to which views from

the Grizzly Giant would be topographically screened, the important character­defining view

of the Grizzly Giant would be minimally affected. Therefore, construction of the new hub

facilities would have no adverse effect on the historic district.

4.	 Engineering Hydrology and Road Improvements. As described for Alternative 2, ecological

restoration of giant sequoia habitat and wetlands would include engineered hydrology

improvements including the repair and replacement of culverts, outsloping of road and trail

surfaces, minor road alignment shifts, road narrowing, removal of asphalt pavement,

localized modifications to historic road prisms, conversion of vehicular roads to pedestrianonly trails, soil decompaction, and revegetation. Specifically, ecological restoration actions

Final Environmental Impact Statement 3­126 October 2013

Chapter 3: Affected Environment and

Environmental Consequences
       

               

   

         

                           

  

                 

                     

                       

                     

                         

                       

                               

                     

                     

                       

                       

                         

               

                       

   

                     

                     

                   

                     

                       

                       

                   

           

                           

                         

                       

                           

                             

                       

                           

                             

                             

                               

                           

                           

                       

                                 

                             

                         

             

                             

                         

                           

                           

                           

                               

    

Cultural Resources: Historic Structures

Restoration of the Mariposa Grove of Giant Sequoias

under Alternative 3 that could affect the Mariposa Grove Historic District would include the

following:

a.	 Drainage Modifications. Culvert repairs and replacement would occur within the

boundaries of the Mariposa Grove Historic District. The culverts are not

contributing elements of the Mariposa Grove Historic District and are not clearly

associated with a particular timeframe within the period of significance, having been

repaired and reconstructed as needed. There are about 60 culverts along the historic

Mariposa Grove Road throughout the Grove that could be repaired or replaced.

Some of the culverts are at the bases of giant sequoias. They vary in construction style

but typically are soil­covered riprap in rock channels, some with minor rock

headwalls. The masonry headwalls are of standard, very simple construction that

does not reflect significant engineering design or artistic construction, or exemplify a

design unique to the Civilian Conservation Corps period to which they are inferred

to date. Culvert repairs and replacement would not alter the integrity of the

contributing road’s location, design, materials, workmanship, feeling, or association.

Therefore, culvert repair or replacement would have no adverse effect on the

historic property.

b.	 Outsloping of Road and Trail Segments. Outsloping would occur within the

boundaries of the Mariposa Grove Historic District along selected contributing and

non­contributing trails and along the extension of Mariposa Grove Road through the

Grove, which is a contributing element of the district. Outsloping would require

regrading, and would result in micro­changes to the elevation and cross­grade, but

would not significantly alter the integrity of the road location, design, materials,

workmanship, feeling, or association. Therefore, outsloping would have no adverse

effect on the Mariposa Grove Historic District.

5.	 Conversion of Paved Road to Accessible Trail in Lower Grove Area. The 10­ to 20­foot­wide

portion of the Mariposa Grove Road would be converted to an 8­ to 10­foot­wide ABAAScompliant accessible loop trail in the ecologically restored lower Grove area. The affected

segments of this historic roadway are within the boundaries of the Mariposa Grove Historic

District, and the road is a contributor to that district. The proposed conversion may require

grade modifications and may introduce a boardwalk to reduce impacts on sensitive wetlands,

but the road prism likely would be retained. To attain ABAAS­compliance, the historic road

alignment also may be altered to incorporate the use of switchbacks and curves not present

in the existing road. Narrowing to less than 8 feet, introduction of a boardwalk, potential

removal of fill from the lower Grove area wetlands, and changes in alignment would result in

a loss of integrity of historic road design, materials, and workmanship. The integrity of

location, setting, and association would be retained and the removal of the asphalt paving

and replacement with an alternative hardened surface would not result in an adverse effect,

but the conversion from a road to a narrower pedestrian trail would alter the design of the

road such that it no longer conveys the feeling of a historic road. Therefore, conversion of

historic road segments to pedestrian trails would have an adverse effect on this contributing

feature in the Mariposa Grove Historic District.

6.	 Conversion of Existing Trail to Accessible Trail at Grizzly Giant. A new, accessible trail would

be developed that connects the new Grizzly Giant hub parking area with an existing

pedestrian trail that connects the lower Grove area with the Grizzly Giant area within the

Mariposa Grove Historic District. This trail would originate at the Grizzly Giant Hub and

would require grading and resurfacing to meet ABAAS, but would not affect the historic

views of the Grizzly Giant. This action would have no adverse effect on the Mariposa Grove

Historic District.

Final Environmental Impact Statement 3­127 October 2013

Chapter 3: Affected Environment and

Environmental Consequences
       

               

   

         

                           

                           

                           

                         

                         

                         

                             

                       

                               

                         

                           

                           

                         

                         

                         

               

                                   

                         

                             

                                   

                             

                     

                                  

                             

                             

                                    

                            

              

                         

                             

                             

                                 

                               

                         

                     

                         

                       

                     

                         

                     

          

                   

                     

                         

                     

                           

                       

                         

Cultural Resources: Historic Structures

Restoration of the Mariposa Grove of Giant Sequoias

7.	 Conversion of Segment of Mariposa Grove Road and Loop Road between Grizzly Giant and

Mariposa Grove Museum, and Wawona Point Spur to a Hardened Trail. The segment of

Mariposa Grove Road between Grizzly Giant and Wawona Point, including a short spur to

the Mariposa Grove Museum and nearby comfort station, would retain the historic road

prisms. However, where possible, the travel­way would be narrowed to a minimum width of

11 feet, asphalt­paved surfaces may be converted to hardened surface, disturbed areas along

the road would be allowed to revert to natural conditions, and existing pullouts would be

assessed and removed where unnecessary. The segment of Mariposa Grove Road between

Grizzly Giant and the museum, and the Wawona Point road, are within the boundaries of the

Mariposa Grove Historic District and are contributors to that district. The integrity of

location, setting, and association would be retained, and resurfacing would not result in an

adverse effect. The road would be narrowed to a minimum width of 11 feet. The characterdefining circulation patterns of the Mariposa Grove Historic District would be retained, and

these segments would continue to convey their feeling as historic roads. Therefore, proposed

modification of these historic roadway segments under Alternative 3 would have no adverse

effect on the historic district or its contributing elements.

8.	 Conversion of the Loop Road in the Upper Grove Area to a Pedestrian Trail. The portion of the

loop road extending from the restrooms in the upper Grove area to the T­intersection with 

the road extending to Wawona Point would be modified from a paved, one­way road (varies

between 12 and 20 feet wide) to a pedestrian trail (from 4 to 6 feet wide). Previously

disturbed road areas would be revegetated. The loop road is within the boundaries of the

Mariposa Grove Historic District, and is a contributing road circulation feature. Although 

the conversion or the road into a trail would retain the historic road prism, the road would

no longer appear as such because of the combination of the removal of the asphalt surfacing,

the significant reduction of its width into a dirt trail, and the revegetation of the disturbed

areas along the trail. As a result, this loop road would no longer convey its feeling as a

historic road. Therefore, this action would have an adverse effect on the historic circulation

system within the Mariposa Grove Historic District.

9.	 Ecological Restoration of Road Margins. The road margins of Mariposa Grove Road between

the lower Grove area and Grizzly Giant, the Mariposa Grove Road and loop road between

Grizzly Giant and the Mariposa Grove Museum, the Wawona Point spur, and the east and

south sections of a paved road loop that is being converted to a pedestrian trail in the upper

Grove area, may be modified. The historic road prism (cut, fill, and road bed) would largely

be retained, but where narrowing occurs, road margins would be ecologically restored. The

modification of road margins could affect the Mariposa Grove Historic District’s characterdefining roadside landscaping, which was created in 1934 and is characterized by the absence

of overhanging banks or protruding root systems of stumps, and reshaped slopes that

conform to the surrounding topography. These landscape features would be reproduced in

the case of modified road/trail shoulders, maintaining the character of the 1934 roadside

landscape design. Therefore, conversion of the historic roadway margins would have no

adverse effect on character­defining roadside landscaping.

10. Improvement of Septic System/Leach Field in the Upper Grove Area. The non­contributing

septic system/leach field in the upper Grove area, which serves the historic comfort station,

has exceeded its service life and would be replaced. These improvements would be

conducted in a manner that would avoid impact on character­defining or contributing

elements of the district, and would therefore have no adverse effect on Mariposa Grove

Historic District.

11. Rehabilitation of Wawona Point Overlook. As described under Alternative 2, the masonry

structures at the overlook would be rehabilitated under Alternative 3 in accordance with the

Final Environmental Impact Statement 3­128 October 2013

Chapter 3: Affected Environment and

Environmental Consequences
       

               

   

         

                       

                       

             

                         

               

                       

                       

                             

                           

                             

                               

                         

                       

                 

                         

                         

                         

                           

                       

                           

                                 

                             

                           

                               

                     

                     

                               

                             

                     

                 

             

                         

                   

                         

                         

                     

                           

                   

                   

                       

                       

   

                     

                           

                           

                             

           

Cultural Resources: Historic Structures

Restoration of the Mariposa Grove of Giant Sequoias

Secretary of the Interior’s treatment standards. Stone masonry would be restored by

repointing and stabilization of side walls. Rehabilitation actions would include installation of

compatible, code­compliant handrails. Landscape modifications would involve ecological

restoration of the abandoned parking area and revegetation that could include screening of

incompatible, modern communications equipment. Historic overlook features would be

stabilized and preserved to the extent possible. These historic rehabilitation actions would

have no adverse effect on Wawona Point, located within the Mariposa Grove Historic

District.

12. Change in Function of Mariposa Grove Museum. Alternative 3 would include a change in the

current use of the building as the Grove’s primary interpretive center to another compatible

use, such as a hiker’s shelter. Physical alteration of the building is not planned under this

project, and any new use would be compatible with the historic use and rustic character of

the building. Should alterations to the building become necessary once a use is determined,

further compliance would be completed as a separate project. Therefore, there would be no

adverse effect on the Mariposa Grove Museum under Alternative 3.

13. Water supply System Repairs and Modifications. As described for Alternative 2, the water

supply storage tank and chlorination unit are within the Mariposa Grove Historic District,

and water distribution pipeline traverse the Mariposa Grove Historic District at its upper

end, and enters the South Entrance Station Historic District at its terminus, where it serves

facilities at South Entrance. These water storage, treatment, and distribution systems are not

contributing elements of either historic district. The water tank and chlorinator are to be

relocated to the vicinity of the upper Grove comfort station as part of this action. The new

location would be chosen so that none of the nearby contributing elements of the Mariposa

Grove Historic District would be affected. The extent of water pipeline repairs needed and

methods for repairs are not yet determined, but the repairs are not be expected to require

removal, realignment, or major alteration of any contributing elements of the Mariposa

Grove Historic District, the Mariposa Grove Museum, or the South Entrance Station

Historic District. Any effects on the setting of the districts caused by repairs to the pipeline

would be temporary, and if any historic materials are removed, they would be replaced in

kind/repaired to their condition prior to construction. Therefore, the water system

modifications would have no adverse effect on historic properties.

14. Structural Sustainability Improvements to Existing Infrastructure. The NPS promotes the

recognition of historic preservation as the best sustainable practice for the historic built

environment. The retention of historic buildings, structures, and cultural landscapes

conserves the natural, labor, and energy resources expended in the original construction and

maintenance of these cultural resources, minimizes the need for additional investment of raw

materials and labor to replace such resources with new construction. The National Park

Service Guiding Principles of Sustainable Design are primarily intended to be applied to new

construction. Many of these sustainability guidelines, which call for designs such as reorientating buildings or constructing vestibules, are not proposed for the contributing

building of the Mariposa Grove Historic District or the Mariposa Grove Museum.

Therefore, sustainability upgrades under Alternative 3 would have no adverse effect on the

historic district.

15. Construction Staging Areas. Construction staging areas needed under Alternative 3 may be

located within or adjacent to the Mariposa Grove Historic District, but staging areas would

be sited to avoid historic features and would be temporary. These temporary staging areas

are expected to affect the Mariposa Grove Historic District, but the effects would not be

adverse. Therefore, there would no adverse effect.

Final Environmental Impact Statement 3­129 October 2013

Chapter 3: Affected Environment and

Environmental Consequences
       

               

   

         

                   

                               

                               

                                     

                         

                                 

                   

                           

                     

                

                     

                         

                       

                             

                           

                         

                       

                             

                   

                             

                   

                       

               

                 

                               

                                

                             

                 

                   

     

                     

                       

                           

   

            

           

            

     

       

Cultural Resources: Historic Structures

Restoration of the Mariposa Grove of Giant Sequoias

Impact Significance and Determination of Effect. Construction and ecological restoration under

Alternative 3 is expected to result in an adverse effect on the Mariposa Grove Historic District.

Although there would be adverse effects to the historic district as a result of this alternative, the

combined actions do not result in a loss of integrity of the historic district as a whole. Ensuring the

long­term health of the Grove remains a primary management objective for both the cultural and

natural resources in all the action alternatives. Adverse effects on the historic district as a result of

implementation of this project alternative would be resolved through consultation with the

California SHPO, in accordance with the NHPA implementing regulations at 36 CFR Part 800, and

implemented through a project­specific MOA to be developed in consultation with the SHPO,

ACHP, and associated American Indian tribes and groups.

Operations­related Impacts. As described for Alternative 2, Alternative 3 would decrease the use

and operational stress on the setting of the Mariposa Grove Historic District and associated

character­defining giant sequoias by eliminating the commercial tram operations and diverting the

majority of vehicular traffic out of giant sequoia groves and habitat. Under Alternative 3, shuttle

service to the Grove would be discontinued. Routine maintenance and repairs would continue, and

repairs to historic buildings, structures, or cultural landscape features would be performed in

accordance with the Secretary of the Interior’s Standards for the Treatment of Historic Properties.

There would be no adverse effects on historic buildings, structures, or cultural landscapes from park

or concessioner operations under Alternative 3 because operating activities would not significantly

alter, directly or indirectly, any of the characteristics of the historic buildings, structures, or cultural

landscapes that qualify them for inclusion in the National Register.

Impact Significance and Determination of Effect. Operation of Alternative 3 would have no

adverse effect on historic buildings, structures, or cultural landscapes.

Conclusion. Under Alternative 3, construction­related actions would adversely affect contributing

elements of the Mariposa Grove Historic District. There would be no modification of facilities at the

South Entrance and no adverse effect in that location under Alternative 3. It is expected that the

following actions would affect historic properties within the APE, but the effects would not be

adverse:

•	 removal of non­contributing structures in the lower Grove area

•	 removal of parking lot in the lower Grove area and replacement with 10­space ABAAScompliant parking area

•	 reduction in number of vault toilets at the lower Grove area

•	 conversion of Mariposa Grove Road between Grizzly Giant and Wawona Point, including

the spur to the Mariposa Museum and upper Grove comfort station, to a hardened

trail/service road

•	 historic rehabilitation of Wawona Point masonry features

•	 refurbishment of the upper Grove leach field

•	 compatible re­purposing of the Mariposa Museum building

•	 habitat restoration measures

•	 cessation of tram operations.

Final Environmental Impact Statement 3­130 October 2013

Chapter 3: Affected Environment and

Environmental Consequences
       

               

   

         

                         

                                     

           

                

                         

                

                             

                         

                                 

              

                     

                                 

                         

                               

                             

       

                             

                   

                         

                             

                                   

                               

                           

                       

                           

                           

                       

                     

                 

                           

                         

                       

                                 

                             

                                   

                         

                             

                             

                     

                     

            

Cultural Resources: Historic Structures

Restoration of the Mariposa Grove of Giant Sequoias

However, modifications to segments of the Mariposa Grove Road at the approach to the lower

Grove and on the upper Grove loop road, and introduction of a new, paved, two­lane road to a new

Grizzly Giant hub would result in:

•	 changes in circulation patterns, traffic, and visitor use,

•	 loss of historic design and feeling where historic road travel­ways are narrowed and
 

converted to hardened roads and pedestrian trails, and
 

•	 loss of location, design, materials, association, and feeling along the segments of road to be

abandoned and ecologically restored (e.g., near the Sentinels) when the new lower Grove

bypass road to the Grizzly Giant hub is constructed, and where the historic road prism is to

be removed (e.g., through the lower Grove wetlands).

These modifications would be considered adverse effects because they would impact the historic

integrity of the road and would alter character­defining views and the sense of arrival at the giant

sequoia grove in the Historic District. Additionally, introduction of a new two­lane, paved bypass

road and bridges to the proposed Grizzly Giant hub would alter the setting, cultural landscape, and

feeling of the Mariposa Grove Historic District, and as such would have an adverse effect on the

integrity of the district.

Adverse effects on historic properties as a result of implementation of this project alternative would

be resolved through consultation with the California SHPO in accordance with the NHPA

implementing regulations at 36 CFR Part 800, and implemented through a project­specific MOA to

be refined in consultation with the SHPO, ACHP, and associated American Indian tribes and groups.

The draft MOA is in Appendix G. The final agreement will be signed before the Record of Decision

is completed and will be included as a part of the decision document for this project.

Park and concessioner operations under Alternative 3 would have no adverse effect on historic

buildings, structures, or cultural landscapes of the Mariposa Grove Historic District because

operating activities would not significantly alter, directly or indirectly, any of the characteristics of

the historic buildings, structures, or cultural landscapes that qualify them for inclusion in the

National Register. Ongoing maintenance of contributing features and buildings would be performed

in accordance with the Secretary of the Interior’s Standards for Treatment of Historic Properties.

Cumulative Impacts. The regional past, present, and reasonably foreseeable projects affecting

historic structures and landscapes would be the same as those under Alternative 1 (No Action)—no

adverse effects on historic structures and landscapes in the Mariposa Grove area. Under

Alternative 3, some proposed actions would affect historic properties, such as demolition of nonhistoric buildings in the lower Grove area, but the effects would not be adverse. Some actions would

constitute an adverse effect on historic circulation patterns and visitor use, such as introduction of a

new, paved two­lane road to a new Grizzly Giant hub. Alternative 3 would not have an adverse effect

on the South Entrance Station Historic District or the Mariposa Grove Museum. The cumulative

effect of past, present, and future projects (no adverse effect), in conjunction with of Alternative 4

(adverse effect), would be an adverse effect on historic properties. Adverse effects would be resolved

through consultation with the California SHPO and traditionally associated American Indian tribes

and groups in accordance with 36 CFR Part 800 (NHPA implementing regulations) and

implemented through a project­specific MOA (Appendix G).

Final Environmental Impact Statement 3­131 October 2013

Chapter 3: Affected Environment and

Environmental Consequences
       

               

   

         

                    

                           

                       

                         

  

                               

                          

                           

                           

                             

                           

               

                               

                  

                             

                                 

                                 

                               

                             

                           

                             

                        

                         

                           

                           

                         

                           

                 

                       

                           

                               

                               

                               

                           

                           

                       

                           

                       

                           

                         

                               

                       

                           

                     

Cultural Resources: Historic Structures

Restoration of the Mariposa Grove of Giant Sequoias

Alternative 4: South Entrance Hub with Modified Commercial Tram Service

Actions under Alternative 4 would be largely as described for Alternative 2, with a few differences:

•	 A new ABAAS­compliant lower Grove loop trail would be constructed with an at­grade,

hardened surface rather than a boardwalk, and limited commercial tram service would be

maintained.

•	 Tram staging would be relocated to a South Entrance Hub, and the tram would operate on an

abbreviated seasonal and daily schedule and along a limited route within Mariposa Grove.

•	 The Mariposa Grove Road would remain asphalt­paved from the lower Grove area to the

Mariposa Grove Museum in the upper Grove area, where a tram turnaround would be

constructed. The upper Grove loop road would be closed to tram traffic, and would be

narrowed and converted to a pedestrian trail, as described under Alternatives 2 and 3.

Construction­ and Restoration­Related Impacts. Construction proposed under Alternative 4 is

expected to result in adverse effects on the Mariposa Grove Historic District to the same extent

described above in Alternative 2, with several exceptions, described as follows:

1.	 Accessible Loop Trail in the Lower Grove Area. A new accessible loop trail would be

constructed at the lower Grove area on the same route as described for Alternatives 2 and 3

(see figure 2­16), but the trail would be at grade with a hardened surface and would not have

a boardwalk finish. The historic road segment to be converted for this use would still be

narrowed to 8 to 10 feet, and alignment and grade modifications to meet ABAAS criteria

could be necessary. These changes could have an adverse effect on the historic integrity of

design and feeling of the contributing road, but the road prism would be largely retained.

2.	 Modify Path of Travel to Upper Grove Comfort Station for ABAAS Compliance.

3.	 Relocation of Commercial Tram Staging Area. The commercial tram staging area would be

moved from the lower Grove area to the new South Entrance Hub. Tram ticketing and

boarding would be incorporated into the same hub footprint as described for Alternative 2,

and effects on the South Entrance Station Historic District and Mariposa Grove Road would

be as described for Alternative 2. Relocation of tram staging to the South Entrance Hub

would have no adverse effect on either historic district.

4.	 Shortened Commercial Tram Route in Mariposa Grove. The commercial tram route would be

shortened relative to the no action alternative (Alternative 1), and would operate on the

existing paved road from the lower Grove area to the Mariposa Grove Museum in the upper

Grove area. The tram would no longer travel the upper Grove one­way loop road from the

water tank to the comfort station, which would be converted for use as a pedestrian trail, as

described under Alternatives 2 and 3. The converted segments would retain the historic road

prisms, and where possible, the travel­way would be narrowed to a minimum width of 11

feet, asphalt­paved surfaces may be converted to hardened surface, disturbed areas along the

road would be allowed to revert to natural conditions, and existing pullouts would be

assessed and removed where unnecessary. The affected segments of Mariposa Grove Road

are within the boundaries of the Mariposa Grove Historic District and are contributors to

that district. The integrity of location, setting, and association would be retained, and

resurfacing would not result in an adverse effect. The road would be narrowed to a minimum

width of 11 feet. The character­defining circulation patterns of the Mariposa Grove Historic

District would be retained, and these segments would continue to convey their feeling as

historic roads. Therefore, proposed modification of these historic roadway segments under

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Cultural Resources: Historic Structures

Restoration of the Mariposa Grove of Giant Sequoias

Alternative 4 would have no adverse effect on the historic district or its contributing

elements.

5.	 Modification of South Entrance Intersection. Under Alternative 4, the existing T­intersection

of Wawona Road and Mariposa Grove Road would be realigned as a modified T­intersection

with Mariposa Grove Road located west of the contributing office building. The driveway to

the ranger duplex would exit from Mariposa Grove Road just north of the modified

T­intersection with Wawona Road. Intersection realignment would avoid effects on

character­defining and contributing elements of the South Entrance Station Historic District

that would diminish the attributes that make them eligible for listing in the National Register.

As described under Alternative 2, modification to the circulation pattern within the South 

Entrance Station Historic District would have no adverse effect because the modified

intersection would retain the primary historic circulation attribute of the junction of the

three roads. Therefore, this intersection modification would have no adverse effect on the

district or on Mariposa Grove Road, which is a contributing element of the Mariposa Grove

Historic District.

6.	 Retain Mariposa Grove Museum Function. Under Alternative 4, the current museum function

as an interpretive center and visitor rest stop would remain at the Mariposa Grove Museum.

No physical alteration of the museum build would occur under this project, so there would

be no effect on the historic property as a result of this action. Should alterations to the

building become necessary once a use is determined, further compliance would be

completed as a separate project.

Please refer to the discussion under Alternative 2: South Entrance Hub for detailed descriptions of

actions common to both Alternative 2 and Alternative 4, and the associated effects on the Mariposa

Grove and South Entrance Station historic districts. These shared actions, and the associated

potential effects on contributing buildings, structures, and landscape features, include:

•	 remove the non­contributing commercial tram staging area and gift shop from the lower

Grove area

•	 substantially reduce the non­contributing in­Grove parking, and relocate primary visitor

parking to the proposed transit hub at South Entrance

•	 rehabilitate historic Wawona Point

•	 make accessibility improvements to Grove trails and the path of travel to the South Entrance

comfort station

•	 replace the septic system/leach field at South Entrance

•	 refurbish  (e.g., relocate and replumb) the septic system and leach  field in the upper Grove

area

•	 construct a new septic/system leach field in the lower Grove area, or installation of a

wastewater pipeline, within the right of way of Mariposa Grove Road, from the lower Grove

area to the South Entrance leach field (may require a lift station near South Entrance)

•	 reconfigure the South Entrance station parking and other non­contributing infrastructure,

and reconfigure the Wawona Road/Mariposa Grove Road intersection.

•	 rehabilitate the segment of the Washburn Wagon Road between the South Entrance hub and

the picnic area along Mariposa Grove Road for use as a pedestrian trail, and construct an

extension of the trail from the picnic area to the lower Grove area

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Cultural Resources: Historic Structures

Restoration of the Mariposa Grove of Giant Sequoias

•	 replace and relocate the water storage and treatment units, and repair/replacement of the

leaking water distribution line in the upper Grove area

•	 convert segments of historic roads for use as pedestrian trails, including removal of asphalt

pavement and revegetation of trail margins within the historic road prism

•	 install an expanded septic system/leach field at South Entrance

•	 refurbish septic system and leach field in the upper Grove area

•	 construct a new septic/system leach  field in the lower Grove area, or installation of a

wastewater pipeline, within the right of way of Mariposa Grove Road, from the lower Grove

area to the South Entrance leach field (may require a lift station near South Entrance)

Impact Significance and Determination of Effect. As with Alternative 2, construction of

Alternative 4 is expected to result in adverse effects on the Mariposa Grove Historic District, which 

is a historic property under Section 106 of the NHPA. Although there would be adverse effects to the

historic district as a result of this alternative, the combined actions do not result in a loss of integrity

of the historic district as a whole. Ensuring the long­term health of the Grove remains a primary

management objective for both the cultural and natural resources in all the action alternatives.

Alternative 4 would also affect the South Entrance Station Historic District, but the effects would not

be adverse. Adverse effects on the historic district historic properties as a result of implementation of

this project alternative would be resolved through consultation with the California SHPO in

accordance with the NHPA implementing regulations at 36 CFR Part 800, and implemented through 

a project­specific MOA to be developed in consultation with the SHPO, ACHP, and associated

American Indian tribes and groups.

Operations­related Impacts. As described for Alternatives 1, 2, and 3, no adverse effect on historic

buildings, structures, or cultural landscapes are anticipated from park or concessioner operations

under Alternative 4. Operational activities, including maintenance and repairs of infrastructure and

facilities and monitoring of traffic/parking, would not significantly alter, directly or indirectly, any of

the characteristics of the historic buildings, structures, or cultural landscapes that qualify them for

inclusion in the National Register. Alternative 4 would decrease the use and operational stress on the

setting of the Mariposa Grove Historic District and associated habitats by reducing infrastructure

and visitor services within the Grove. Operations under Alternative 4 would not result in physical

destruction or damage; alteration inconsistent with the Secretary of the Interior’s Standards for the

Treatment of Historic Properties; disposal of the property; incompatible change in the character of the

property’s use or setting; introduction of incompatible visual, atmospheric, or auditory elements; or

neglect or deterioration.

The management of and routine maintenance and repair of historic buildings, structures, and

cultural landscapes would continue to be implemented in keeping with the Secretary of the Interior’s

Standards for the Treatment of Historic Properties.

Impact Significance and Determination of Effect. Operation under Alternative 4 would have no

adverse effect on historic buildings, structures, or cultural landscapes within the Mariposa Grove

and South Entrance Station historic districts.

Conclusion. As described for Alternative 2, under Alternative 4, construction­related actions

related to restoration of hydrologic function of giant sequoia habitat, and to accessibility upgrades to

trails and facilities, would result in alteration of design, materials, workmanship, and/or feeling of the

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Cultural Resources: Historic Structures

Restoration of the Mariposa Grove of Giant Sequoias

contributing Mariposa Grove Road, and would therefore have an adverse effect on the Mariposa

Grove Historic District.

It is expected that the following actions would affect historic properties within the APE, but the

effects would not be adverse:

•	 reconfiguration of the intersection at the South Entrance

•	 construction of new South Entrance infrastructure

•	 removal of the lower Grove non­historic structures and infrastructure and construction of

new lower Grove infrastructure

•	 rehabilitation of the Washburn Wagon Road for use as a pedestrian trail from South 

Entrance to the picnic area and extension of a new trail to the lower Grove area
 

•	 minor engineered hydrology and road improvements including repair and replacement of

culverts and outsloping

•	 refurbishing of the upper Mariposa Grove leach field and expansion/relocation of the South 

Entrance leach field

•	 Construction of a septic system/leach field at the lower Grove area or installation of a

wastewater pipeline from the lower Grove area to the South Entrance septic system/leach 

field along the right of way of the Mariposa Grove Road

•	 ABAAS improvements to paths of travel to the historic comfort stations in the upper Grove

area and at South Entrance

•	 rehabilitation of Wawona Point overlook

•	 repair of the Mariposa Grove and South Entrance water supply system

•	 construction staging areas

Adverse effects on historic properties as a result of implementation of this project alternative would

be resolved through consultation with the California SHPO in accordance with the NHPA

implementing regulations at 36 CFR Part 800, and implemented through a project­specific MOA to

be developed in consultation with the SHPO, ACHP, and associated American Indian tribes and

groups. Concessioner and NPS operations at Mariposa Grove and South Entrance under

Alternative 4 would have no adverse effect on historic buildings, structures, or cultural landscapes.

Cumulative Impacts. The regional past, present, and reasonably foreseeable projects affecting

historic structures and landscapes would be the same as those under Alternative 1 (No Action)—no

adverse effects on historic structures and landscapes in the Mariposa Grove area. Under

Alternative 4, some proposed actions would affect historic properties, such as demolition of nonhistoric buildings in the lower Grove area, but the effects would not be adverse. Some actions would

constitute an adverse effect on the Mariposa Grove Historic District, such as the conversion of the

Mariposa Grove Road to an ABAAS­compliant loop trail. Alternative 4 would not have an adverse

effect on the South Entrance Station Historic District or the Mariposa Grove Museum. The

cumulative effect of past, present, and future projects (no adverse effect), in conjunction with of

Alternative 4 (adverse effect), would be an adverse effect on historic properties. Adverse effects

would be resolved through consultation with the California SHPO and traditionally associated

American Indian tribes and groups in accordance with 36 CFR Part 800 (NHPA implementing

regulations) and implemented through a project­specific MOA (Appendix G).

Final Environmental Impact Statement 3­135 October 2013

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Cultural Resources: American Indian Traditional Cultural Resources

Restoration of the Mariposa Grove of Giant Sequoias

AMERICAN INDIAN TRADITIONAL CULTURAL RESOURCES

Introduction and Definitions

Traditional cultural resources are defined as “objects and places, including sites, structures,

landscapes, and natural resources, with traditional cultural meaning and value to associated peoples”

(NPS 2006). Traditional cultural practices involve resources that are:

•	 culturally valued tangible locations,

•	 involve social use of the biophysical, geophysical, or built environment, and

•	 reflect socio­cultural attributes, including social cohesion, lifeways, religious practices, and

other social institutions, such as education and recreation, that play out in the biophysical

and built environments, but are not tangible in and of themselves.

If an American Indian traditional cultural resource or practice meets any of the eligibility criteria for

listing in the National Register (36 CFR 60.4), it is considered a historic property with traditional

cultural or religious significance. However, many resources and practices that are significant to

contemporary American Indian tribes or groups do not meet the National Register criteria, but the

cultural value of these resources may have acquired a historic merit through repeated use over time.

The NPS (2006) is committed to protecting and preserving traditional cultural resources that do not

qualify as historic properties, but that are culturally significant to traditionally associated American

Indian peoples.

Affected Environment

Although no previous ethnographic research has been identified that focuses exclusively on the

Mariposa Grove of Giant Sequoias, other source materials have been identified that demonstrate

that numerous tribal groups have, and continue to, value and utilize giant sequoia groves regionally.

The presence of multiple prehistoric archeological sites and extensive fire scarring in the Mariposa

Grove, as well as information learned from recent interviews and consultations with contemporary

traditionally associated peoples, confirm that Mariposa Grove was a traditionally significant area,

beginning at least 3,500 years ago (Hull 1989, Anderson 1993, Goldberg et al. 2012).

Tribal groups identified as historically frequenting giant sequoia groves on the western slopes of the

central and southern Sierra Nevada include the Nisenan or Southern Maidu; the Western Mono;

various Foothill Yokuts cultural groups; the Southern, Central, and Northern Sierra Miwok; the

Tubatulabal; and several groups from the eastern side of the Sierra Nevada, including the Washoe,

the Northern Paiute (e.g., the Mono Lake Kudzedikaa), and the Owens Valley Paiute (Anderson

1993, Latta 1977, Powers 1976). Recent ethnographic interviews conducted with park­associated

American Indians note the particular salience of giant sequoias and Mariposa Grove to Southern and

Central Sierra Miwok, Chukchansi Yokuts, and Western Mono peoples (Anderson 1993). These

groups are directly related to contemporary American Indian groups, nearly all of whom have

documented traditional associations with Yosemite National Park and the Mariposa Grove of Giant

Sequoias. The park currently consults with seven traditionally associated American Indian tribes and

groups: The American Indian Council of Mariposa County, Inc. (also known as the Southern Sierra

Miwuk Nation), Bishop Paiute Tribe, Bridgeport Indian Colony, Mono Lake Kutzadikaa Tribe,

North Fork Rancheria of Mono Indians of California, Picayune Rancheria of the Chukchansi

Indians, and Tuolumne Band of Me­Wuk Indians.

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Cultural Resources: American Indian Traditional Cultural Resources

Restoration of the Mariposa Grove of Giant Sequoias

There likely are numerous reasons why the ethnographic record is largely lacking specific data about

traditional use of the Mariposa Grove and other giant sequoia groves. Early non­indigenous visitors

to Mariposa Grove did little to document native use of the area beyond vilifying the Indians’

deliberate use of fire (Brace 1869; Muir 1961). By the time outsiders first saw the Mariposa Grove

circa 1855, American Indian lifeways had been drastically disrupted in the region due to

missionization, disease, reduced access to resources, and the subsequent population decline and

changes in marriage patterns and other cultural practices (Bunnell 1859; Davis­King 1999).

The limited ethnographic information that is available indicates that the giant sequoias were

considered sacred by the American Indian peoples (Anderson 1993; Goode 1992). It further suggests

that the giant sequoia groves were areas where initiations or other important ceremonies were

performed (Anderson 1993).

Ethnographers have documented at least 12 different words for the giant sequoia in American Indian

languages (Powers 1976, Bunnell 1990, Anderson 1993, Davis­King 1999). At least 7 of these words

are variations of the word wah­wo­nah, suggesting connections to the Mariposa Grove of Giant

Sequoias in the area now known as Wawona. Powers (1976:398) reported that the Western Mono

variant—woh­woh’­nau—was meant to imitate “... the hoot of the owl, which is the guardian spirit

and deity of this great monarch of the forest.”

The Mariposa Grove of Giant Sequoias contains extensive evidence of anthropogenic fires. These

fires were undoubtedly started by American Indians who understood that giant sequoia seedlings

and giant sequoia habitat thrive in response to frequent fires. American Indians ignited fires in the

giant sequoia groves in order to prolong the lifecycles of the big trees, to clear brush from trails, to

attract game, and to improve the growth of specific plant materials. Data from ethnographic

interviews conducted previously also show that most fires in the giant sequoia groves burned in the

late growing season, between early August and October or November (Anderson 1993, Goldberg

et al. 2012).

Indigenous uses of giant sequoias include use of the bark for housing material by Central Sierra

Miwok, Yokuts, and Paiute tribes (Barrett and Gifford 1933, Anderson 1993). It has also been

reported that Yokuts groups used the pitch from the giant sequoia bark as a medicine, and that the

fumes from burning the gum were used to treat neuralgia (Hudson 1901, Anderson 1993:257).

Besides the giant sequoias themselves, numerous plants and animals valued by park­associated

American Indians are found in or in close proximity to giant sequoia groves. These plants include,

but are not limited to, elderberry, wild onion, sugar pine, hazelnut, chinquapin, soaproot, strawberry,

grass seeds, sedge, mushrooms, alder, dogwood, currant, and raspberry. Many plants had multiple

uses, and filled needs for medicine, subsistence, and/or spiritual purposes (Goldberg et al. 2012).

Important basketry plants are also found growing in or around giant sequoia groves including

willow, hazelnut, black oak, buck brush, deer brush, maple, and bitter cherry (Goldberg et al.

2012:38).

Much of the fauna that historically inhabited giant sequoia groves also played a major role in

American Indian traditional practices and beliefs. Many faunal species have spiritual significance, in

addition to filling subsistence and other needs. Research has identified several traditionally

significant faunal species including, but not limited, to owls, falcons, eagles, bears, beavers, deer, elk,

fish, coyote, and caterpillars. As an example of spiritual significance, the North Fork Mono (a band

of Western Mono) considered the golden eagle to be the creator and the chief of the birds. This

species was revered by both of the North Fork Mono moieties, while they considered the bald eagle

a totem of the Pakwihu moiety (Gifford 1932). The Chukchansi Yokuts moieties were eagle and

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Cultural Resources: American Indian Traditional Cultural Resources

Restoration of the Mariposa Grove of Giant Sequoias

coyote (Gayton 1948). Several American Indian groups (e.g., Western Mono, Miwok, and Yokuts)

are reported to have collected caterpillars, grubs, or worms for food.

Extensive changes since the arrival of Anglo­Americans and other cultural and ethnic groups have

affected the ability of American Indian tribes and groups who traditionally used the Mariposa Grove

to access resources there. However, contemporary tribal groups have maintained strong connections

to Mariposa Grove as part of their continuing cultural heritage. Recent ethnographic interviews

conducted with park­associated American Indians note the particular importance of the Mariposa

Grove to Southern and Central Sierra Miwok, Chukchansi Yokuts, and Western Mono peoples

(Goldberg et al. 2012). It is important to note that archeological resources are highly valued by

American Indians who have traditional associations with Yosemite National Park. Archeological

sites, including those within and near the Mariposa Grove of Giant Sequoias and South Entrance,

continue to be vital components of American Indian cultural patrimony, and reflect tangible links to

ancestral occupation, burial grounds, and places of prayers and other ceremonial activities. The

importance of these sites was affirmed during consultation meetings among Yosemite National Park

staff and associated American Indian tribes and groups in 2011, and a consultation site visit to the

Mariposa Grove of Giant Sequoias in January and May 2012, and April and July 2013. Several tribal

representatives stated that the “protection of documented prehistoric archeological resources in the

Grove from future development is of paramount concern” (Goldberg et al. 2012:11). Park­associated

American Indians have expressed a cultural connection to Mariposa Grove, which indicates that the

Grove would have high value for continuing traditional cultural practices.

Environmental Consequences

Impact Analysis Methodology

No historic properties with traditional cultural or religious significance (beyond archeological sites)

have currently been identified within the Restoration of the Mariposa Grove of Giant Sequoias

project area, therefore, impacts on traditional cultural resources are assessed under NEPA in this

Mariposa Grove FEIS.

Pursuant to NEPA regulations (40 CFR 1500­1508), project impacts are evaluated based on the

criteria of context and intensity. Context means the affected environment in which a proposed

project occurs. Intensity refers to the severity of the effect, which is examined in terms of the type,

quality, and sensitivity of the resource involved, location and extent of the effect, duration of the

effect (short­ or long­term), and other consideration of context. Beneficial and adverse effects are

considered. When no measurable effect is identified, impact is found not to occur. The intensity of

impacts is the degree or magnitude of a potential impact, described as negligible, minor, moderate, or

substantial. Context and intensity are considered together when determining whether an impact is

significant under NEPA.

The impact intensities criteria for those traditional cultural resources within the project area that are

significant to park­associated American Indians are defined below. Note that archeological

resources are evaluated in a separate section of this Mariposa Grove FEIS:

•	 Negligible Impact Intensity – the impact would be at the lowest levels of detection, barely

measurable, with no perceptible consequences either adverse or beneficial to the resources.

•	 Minor Impact Intensity – the impact is measurable or perceptible, but it is slight and affects a

limited area of a resource or group of resources.

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Cultural Resources: American Indian Traditional Cultural Resources

Restoration of the Mariposa Grove of Giant Sequoias

• Moderate Impact Intensity – the impact is measurable and perceptible.

• Major Impact Intensity – the impact is substantial, noticeable, and permanent.

Alternative 1: No Action

Alternative 1, existing infrastructure; current Mariposa Grove concessioner facilities, operations, and

maintenance; and current NPS management and shuttle operations would remain unaltered. No

infrastructure renovation or improvements or ecological restoration actions, such as modification of

Grove transit and parking operations; removal or upgrading of existing facilities; construction of new

facilities and infrastructure; improvement of visitor way­finding, interpretation, and universal access;

improvement of hydrologic flows; project­specific prescribed fire and hazardous fuel reduction

treatments, or soil decompaction, would be implemented.

Operations­related Impacts. Current concessioner and park operations at the Mariposa Grove

would be maintained under the no action alternative (Alternative 1). American Indians who are

traditionally associated with the Mariposa Grove have maintained a strong connection to the Grove

and have expressed a special, vital relationship with the Grove, and specifically with the giant

sequoias, which are considered sacred. Traditionally associated American Indian tribes and groups

also have continuing cultural connections with all of the prehistoric archeological sites within the

project area (see Archeology section of this chapter), especially site CA­MRP­0661/H in the lower

portion of the Grove. Under Alternative 1, current assured access to the Mariposa Grove afforded by

the NPS to American Indians with local cultural associations would remain unchanged. However,

many of the values that American Indians associate with the Grove, such as the general health of the

giant sequoia ecosystem, continued availability of flora and fauna important for traditional uses, and

archeological site conditions at South Entrance and Mariposa Grove, would continue to be affected

by visitor facilities (e.g., parking areas, the gift shop), visitor use, and operational practices (e.g.,

commercial tram and gift shop operations, use of the Grove and South Entrance areas, lack of

ecological restoration throughout the Grove and at Wawona Point). Furthermore, the current lack of

interpretation of traditional cultural practices and resources within Mariposa Grove would continue.

Impact Significance. Giant sequoia groves have been important to native cultures over the

millennia. The trees themselves are considered sacred, and ethnographic data suggest that the groves

were areas where initiations or other important ceremonies were performed. The giant sequoia

ecosystem also supports a number of fauna and flora species that have traditional importance, both 

spiritual and subsistence­related, to traditionally associated American Indians. The American Indian

archeological sites within the project area also are important to traditionally associated tribes and

groups. Alternative 1 would have long­term, moderate, adverse impacts on Mariposa Grove habitat,

and long­term negligible adverse impacts under NEPA on archeological sites that are traditionally

significant to associated American Indians.

Conclusion. Under the no action alternative (Alternative 1), the current conditions and operations

at the Mariposa Grove would remain unchanged. The health of the giant sequoia ecosystem at the

Mariposa Grove would continue to be impacted by unnecessary infrastructure located within the

Grove, and the potential for adverse impacts at archeological sites would continue through 

unauthorized collection of artifacts or vandalism. There would continue to be limited interpretation

of American Indian traditional cultural resources and practices in this area of the park. Current

access to the Mariposa Grove by American Indian tribes to pursue traditional cultural practices

would not be altered. Overall, Alternative 1 is the only alternative that would not result in noticeable

(i.e. more than negligible) adverse impacts on culturally significant characteristics of archeological

sites that are considered important traditional cultural resources by American Indians associated

Final Environmental Impact Statement 3­139 October 2013

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Cultural Resources: American Indian Traditional Cultural Resources

Restoration of the Mariposa Grove of Giant Sequoias

with the project area. However, moderate adverse impacts on the giant sequoia habitat would

continue.

Cumulative Impacts. The cumulative impacts on American Indian traditional cultural resources

discussed in this section considers past, present, and reasonably foreseeable actions in the Mariposa

Grove area (Appendix B), in combination with potential impacts of Alternative 1 (No Action). The

timeframe for this analysis encompasses the period after the Mariposa Grove became a part of the

Yosemite Land Grant in 1864, and the period after 1932 for areas near the South Entrance, after the

NPS acquired the area. Before these periods, the ability for American Indians to hunt, gather,

conduct controlled burns, and practice traditional ceremonies was already dramatically reduced.

Significant logging had occurred near the South Entrance. Installation of the South Entrance Station

and ranger residence provided controlled access into the park through this southern portal.

Current plans and projects in the Mariposa Grove area would have beneficial and adverse impacts

on areas of traditional plant use (Appendix B). The Parkwide Invasive Plant Management Plan Update

and the Wawona Meadow Restoration Project would result in long­term beneficial impacts on areas

of traditional plant use. Activities associated with the Fire Management Plan/Operational Fire

Management Plan and U.S. Forest Service fuels reduction projects would greatly reduce the threat of

large high­severity catastrophic fires, and reduce the potential for vegetation type conversion. These

actions would have a long­term beneficial impact on areas of traditional plant use.

There would be adverse impacts on areas of traditional plant use associated with the current South 

Entrance Station Kiosks Replacement project, the Scenic Vista Management Plan due to the localized

loss of vegetation. Site­specific adverse impacts on vegetation could be short­term (during

construction) and long­term (direct displacement of vegetation). The NPS would endeavor to avoid

adverse impacts on traditional cultural resources such as areas of traditional plant use during the

design phase for these projects. Where such avoidance is not feasible, the NPS, in consultation with 

traditionally associated American Indian tribes and groups, would mitigate the impacts to the

greatest extent possible. Overall, there would be a long­term minor beneficial impact on traditional

cultural resources as a result of past, present, and current projects.

Under Alternative 1 (No Action), there would be a long­term moderate adverse impact on traditional

cultural resources in the Mariposa Grove. These impacts include ongoing impacts to giant sequoia

habitat, the availability of flora and fauna important for traditional uses, and archeological site

conditions that would continue to be affected by visitor facilities in the grove such as parking lots

and the gift shop.

In summary, past impacts on traditional cultural resources in the region have been adverse, longterm, and minor. Present and foreseeable future actions would contribute to reversing the adverse

impacts of past actions in the Mariposa Grove area. Under Alternative 1, there would be a long­term

moderate adverse impact on traditional cultural resources in the Mariposa Grove. Past, present, and

future impacts, in conjunction with the impacts of Alternative 1 (No Action), would result in a longterm moderate adverse impacts on traditional cultural resources in the Mariposa Grove area.

Alternative 2: South Entrance Hub (Preferred Alternative)

Alternative 2 would remove the commercial tram operations and reduce the amount of impervious

surfaces and structures in the lower portion of the Grove, while relocating primary visitor parking to

South Entrance. New visitor services at the South Entrance area would include visitor information,

educational, and other sales items. The water tank and chlorination unit on the loop road in the

upper portion of the Grove would be moved to a nearby location outside of sequoia habitat, and the

gift shop in the lower portion of the Grove and existing vault toilets at Grizzly Giant and in the upper

Final Environmental Impact Statement 3­140 October 2013

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Cultural Resources: American Indian Traditional Cultural Resources

Restoration of the Mariposa Grove of Giant Sequoias

portion of the Grove would be removed. Numerous other repairs, renovations, and ecological

restoration actions, such as water line repair or replacement, replacement of the lower Grove vault

toilets with flush toilets, installation of a new septic system and leach field in the lower portion of the

Grove, historic rehabilitation of Wawona Point features, and soil decompaction would be

components of this alternative. Interpretation of cultural and natural resources would be enhanced.

The intersection of Mariposa Grove Road and Wawona Road at South Entrance would be realigned,

and a roundabout could replace the existing T­intersection if needed to address traffic congestion

near the South Entrance.

Construction­related Impacts. Demolition and removal of structures and pavement, staging of

materials and equipment, construction of redesigned facilities, renovation of existing structures,

installation of a new leach field, grading and recontouring for hydrological and ecological restoration

purposes, and development of new accessible trails in the lower Grove area all would involve ground

disturbance, which carries with it the potential to adversely impact archeological resources,

including two archeological sites for which local American Indian tribes have expressed a vital

connection and a desire for better protection from development and vandalism. Construction

activities also could temporarily disturb wildlife and plant communities. Recontouring and

replanting of reclaimed areas currently covered by pavement or buildings at the conclusion of

construction would ensure that these are temporary impacts.

Construction of a new parking area at the South Entrance would impact nearly half of site

CA­0660/H. In addition, extensive clearing would be required prior to construction would be a

moderate adverse impact on traditional cultural resources. Actions in the lower Grove area that have

the potential to adversely impact CA­MRP­0661/H include installation of a new shuttle turnaround,

removal of existing roads and parking areas, and ecological restoration of modified areas. Parking

reconfiguration in this area would seek to avoid excavation and rely on use of fill material to avoid

impacting surface features. Black oak trees would be left in place in the vicinity of the archeological

site, and elsewhere where feasible. The gift shop at the lower portion of the Grove would be removed

from the vicinity of site CA­MRP­0661/H.

Impact Significance. Construction activity under Alternative 2 would adversely affect two

archeological sites important to culturally associated American Indian tribes and groups who have

expressed concern about protecting these resources from future development. There is potential for

moderate adverse impacts on site CA­MRP­00660/H from construction of the parking lot at the

South Entrance. In addition, extensive clearing of the site would be a moderate adverse impact on

traditional cultural resources.

Impacts to site CA­MRP­0661/H in the lower Grove area would be minor, as design would avoid

ground­disturbance and impacts to black oaks in the vicinity of the site. Removal of the parking area

and gift shop away from CA­MRP­0661/H at the lower portion of the Grove would be a beneficial

impact.

Restoration­related Impacts. Restoration activities, under Alternative 2 would improve the overall

health of the giant sequoias at the Mariposa Grove. These actions, which would include increasing

habitat area, decompaction of soils, improving hydrology, reforestation, and prescribed burns,

would enhance values important to American Indians with a cultural association to the groves, some

of whom are interested in the restoration and preservation of flora and fauna species for traditional

uses. The use of prescribed burns to restore habitat is particularly supported by traditionally

associated American Indians. The park would work with associated tribes and groups to improve

conditions in the Grove for flora and fauna species important to American Indian tribes and groups.

Alternative 2 restoration of the lower portion of the Grove would, on the other hand, have

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Cultural Resources: American Indian Traditional Cultural Resources

Restoration of the Mariposa Grove of Giant Sequoias

temporary adverse impacts on traditionally significant archeological site CA­MRP­0661/H through 

reconditioning of soils where facilities have been removed, and the planting of native vegetation.

While reclamation and revegetation of surfaces for ecological restoration purposes would further

disturb archeological resources and giant sequoia habitat (see impact significance described above

for construction impacts), these actions would lead to long­term beneficial impacts as more natural

conditions are restored and site surfaces are stabilized.

Impact Significance. An improved giant sequoia ecosystem through restoration, especially

prescribed burns, would have a beneficial impact on those characteristics of Mariposa Grove that are

important to traditionally associated American Indians by restoring native vegetation, which in turn

would attract native fauna. Temporary, minor adverse impacts on traditionally significant site

CA­MRP­0661/H would occur from restoration actions at the lower portion of the Grove.

Operations­related Impacts. Operations under Alternative 2 would continue to allow traditionally

associated American Indian tribes and groups to have access to the Mariposa Grove and the South 

Entrance for traditional practices. There is the potential for continued unauthorized collection of

surface archeological artifacts from sites CA­MRP­0660/H and CA­MRP­0661/H under

Alternative 2. American Indians traditionally associated with these sites have expressed a desire that

the sites be protected from vandalism. If construction and operation of a leach field cannot be

designed to avoid impacts on the traditionally significant archeological site (CA­MRP­0661/H), then

a sewer line or vault toilets would be installed instead. Implementation of Alternative 2 would

provide for additional public information about and interpretation of American Indian traditional

cultural resources and practices, which would be a beneficial impact under this alternative. The need

for increased public information about American Indian history and cultural practices has been

repeatedly expressed by tribal representatives during project consultation. The reduced

concentration of visitor parking at the lower portion of the Grove would enhance the natural

ambience of the Grove and, thus, enhance the features of the Grove that are important to

traditionally associated American Indians.

Impact Significance. Potential vandalism would have a long­term, minor, adverse impact on

significant cultural resources under Alternative 2. Enhanced interpretation of traditional cultural

resources and practices would have a long­term, beneficial impact on these resources at both the

lower Grove area and at South Entrance. Removal of the parking area and gift shop away from

CA­MRP­0661/H at the lower portion of the Grove would have a beneficial impact.

Conclusion. Restoration activities to improve the health of the giant sequoia ecosystem at the

Mariposa Grove would have long­term, moderate to major beneficial impacts on those values

attributed to the Grove by American Indians with cultural associations to the Grove. Alternative 2

would continue to allow traditionally associated American Indians to have access to Mariposa

Grove, Wawona Point, and South Entrance to pursue traditional cultural practices, and the

expansion of visitor education and interpretation would enhance understanding and appreciation of

archeological and traditional cultural resources at the Mariposa Grove. These actions would have

long­term, moderate beneficial impacts. The removal of the parking area and gift shop from site CAMRP­0661/H in the lower Grove area would also have a beneficial impact.

Alternative 2 construction actions, including to the removal of structures and paved areas, would

have a long­term, moderate to major adverse impact on archeological site CA­MRP­0660/H. In

addition, extensive clearing of the site would be a moderate adverse impact on traditional cultural

resources.

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Restoration of the Mariposa Grove of Giant Sequoias

There would be a short­term, minor adverse impact on archeological site CA­MRP­0661/H. Final

design of facilities in the vicinity of this site would avoid or minimize potential impacts on the site.

Any parking reconfiguration in this area would seek to avoid excavation and rely on use of fill

material to avoid impacting surface features. Mature black oak trees would be left in place in the

vicinity of site CA­MRP­0661/GH and elsewhere, where feasible. Traditionally associated American

Indian tribes and groups have specifically expressed concern about future development at these

sites.

Overall, there would be a long­term moderate to major adverse impact on traditional cultural

resources, largely from the loss of site CA­MRP­0660/H at the South Entrance, and the extensive

clearing required as part of the South Entrance parking lot construction. Adverse effects would be

resolved through consultation with the California SHPO in accordance with the NHPA

implementing regulations at 36 CFR Part 800, and implemented through a project­specific MOA to

be developed in consultation with the SHPO, ACHP, and associated American Indian tribes and

groups.

Cumulative Impacts. The regional past, present, and reasonably foreseeable projects affecting

traditional cultural resources would be the same as those under Alternative 1 (No Action)—an

overall long­term minor adverse impact on traditional cultural resources in the Mariposa Grove area.

Under Alternative 2, there would be a long­term beneficial impact on the giant sequoia ecosystem

with respect to restoration of giant sequoia habitat. The NPS would work with tribes and groups to

improve accessibility to important resources and enhance interpretation of American Indian

traditions and practices in Mariposa Grove. The reduction of automobile traffic within the Grove’s

giant sequoia habitat would improve the overall Grove experience. There would be major adverse

impacts to the historic archeological site at the South Entrance in the lower Grove area, and minor

impacts to the archeological site in the lower Grove area. In addition, loss of trees during

construction of the South Entrance parking lot would be a long­term adverse impact on traditional

cultural resources. Overall, there would be a long­term moderate to major impact on traditional

cultural resources under Alternative 2.

The impacts of Alternative 2, in conjunction with the impacts from other past, present, and

reasonably foreseeable projects affecting traditional cultural resources, would have an overall longterm moderate to major adverse impact on traditional cultural resources in the Mariposa Grove area.

Mitigation developed in consultation with traditionally associated tribes and groups would be

applied during project implementation, as described in a project­specific MOA (Appendix G).

Alternative 3: Grizzly Giant Hub

Alternative 3 would remove the commercial tram operation and build a new bypass road, including

two new bridges, and a new parking lot near the Grizzly Giant, but outside of giant sequoia habitat.

This alternative would make the Grizzly Giant the primary arrival point for visitors to the Grove. The

current South Entrance parking lot would remain as is, and the parking lot in the lower Grove area

would be removed and a small lot of ABAAS­compliant spaces would be constructed. The gift shop

and commercial tram staging area in the lower portion of the Grove also would be removed, and the

comfort station would be replaced. Numerous other repair, renovation, and ecological restoration

actions, such as improvement of hydrologic flow, project­specific prescribed fire and hazardous fuel

reduction treatments, soil decompaction, utility upgrades and relocations, universal access, and

improvement of visitor orientation and interpretation, would be components of this alternative.

Construction­related Impacts. Construction of Alternative 3 would adversely impact one

archeological site for which local American Indian tribes have expressed a vital connection and a

desire for better protection from development and vandalism. Potential impacts on

Final Environmental Impact Statement 3­143 October 2013

Chapter 3: Affected Environment and

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Cultural Resources: American Indian Traditional Cultural Resources

Restoration of the Mariposa Grove of Giant Sequoias

CA­MRP­0661/H would occur at the lower Grove area from construction of a new bypass road to

the Grizzly Giant Hub, which would bisect this site and alter the character of the topographic

features in the immediate site vicinity. The installation of a smaller, relocated comfort station and

accessible parking area, and the removal of the gift shop, exiting comfort station, commercial tram

staging area, and existing roads and parking areas that are located on or near the site would also

impact the site.

Some traditionally associated tribal representatives have questioned the need to construct a new

road through a section of older growth forest when one already exists (the historic road). To damage

the old growth mixed conifer forest to benefit sequoia restoration seemed inappropriate because the

forest habitat had already begun recovery from previous road construction.

Impact Significance. Removal, road and facility construction, and reclamation of areas for

ecological restoration in the lower Grove area under Alternative 3 would have a short­term, minor to

moderate adverse impact on one archeological site that is traditionally significant to associated

American Indians who expressed concern about protecting such resources from future

development, and in particular about creating a second road corridor that would damage and

degrade the natural setting.

Restoration­related Impacts. Restoration activities under Alternative 3 would improve the overall

health of the giant sequoias at the Mariposa Grove. These actions, which include increasing habitat

area, decompaction of soils, improving hydrology, reforestation, and prescribed fires, would

enhance values important to American Indians with a cultural association to the groves, some of

whom are interested in the restoration and preservation of flora and fauna species for traditional

uses. The use of prescribed burns to restore habitat in particular is supported by traditionally

associated American Indians. The Park would work with tribes and groups to improve conditions in

the Grove for flora and fauna important to American Indians. Alternative 3 ecological restoration in

the lower portion of the Grove would, on the other hand, have short­term, minor adverse effects on

traditionally important archeological site CA­MRP­0661/H due to contouring, soil reconditioning,

and the re­establishment of native flora.

Impact Significance. Improved giant sequoia habitat through restoration, especially prescribed

burns, would have a beneficial impact on those characteristics of the Grove that are important to the

traditionally associated American Indians by restoring native vegetation, which, in turn, would

attract native fauna. Short­term, minor adverse impacts on traditionally significant site

CA­MRP­0661/H would occur due to restoration actions in the lower portion of the Grove.

Operation­related Impacts. Operations under Alternative 3 would continue to allow traditionally

associated American Indians to have access to the Mariposa Grove and the South Entrance for

traditional practices. There is the potential for continued unauthorized collection of surface

archeological artifacts from site CA­MRP­0661/H under Alternative 3. American Indians

traditionally associated with these sites have expressed a desire that they be protected from

vandalism. Improved information about native cultures and traditional resources and practices

would also occur under Alternative 3.

Impact Significance. Archeological site CA­MRP­0661/H, which is of interest to traditionally

associated American Indian tribes and groups, would likely be subject to long­term, minor adverse

impacts by unauthorized collection of artifacts. Use of the new bypass road and Grizzly Giant Hub

would have direct, moderate to major long­term adverse impacts on the archeological site and on

forested areas at the edges of the giant sequoia groves. However, improved interpretation would

Final Environmental Impact Statement 3­144 October 2013

Chapter 3: Affected Environment and

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Cultural Resources: American Indian Traditional Cultural Resources

Restoration of the Mariposa Grove of Giant Sequoias

have a long­term beneficial impact on traditional cultural resources by improving visitor

understanding and appreciation of these resources.

Conclusion. Restoration activities to improve the health of the giant sequoia ecosystem at the

Mariposa Grove would have a long­term beneficial impact on those values attributed to the Grove by

American Indians who have a cultural association with the Grove, Alternative 3 would continue to

allow traditionally associated American Indian tribes to have access to the Mariposa Grove and the

South Entrance for traditional practices, and the consolidation and expansion of visitor education at

Grizzly Giant would enhance the interpretation of archeological and traditional cultural resources at

the Mariposa Grove. These actions would have long­term, moderate beneficial impacts on

traditional cultural resources.

Alternative 3 construction actions would have a short­term, minor to moderate, adverse impact on

archeological site CA­MRP­0661/H, for which traditionally associated American Indian tribes and

groups have specifically expressed concern about future development. Continued use of the new

bypass road to Grizzly Giant would also have a long­term moderate to major long­term impact on

archeological site CA­MRP­0661/H and traditional cultural resources, as it would introduce high 

volumes of visitor traffic into an area of known cultural use by American Indian people, as indicated

by the presence of archeological resources.

Cumulative Impacts. The regional past, present, and reasonably foreseeable projects affecting

traditional cultural resources would be the same as those under Alternative 1 (No Action)—an

overall long­term minor adverse impact on traditional cultural resources in the Mariposa Grove area.

Under Alternative 3, there would be a long­term beneficial impact on the giant sequoia ecosystem

with respect to restoration of giant sequoia habitat. The NPS would work with tribes and groups to

improve accessibility to important resources and enhance the interpretation of American Indian

traditions and practices in Mariposa Grove. The reduction of automobile traffic within the Grove’s

giant sequoia habitat would improve the overall Grove experience. The loss of trees required during

construction of the Grizzly Giant hub and access road would be a long­term major adverse impact

on traditional cultural resources. Overall, there would be a long­term major impact on traditional

cultural resources under Alternative 3.

The impacts of Alternative 3, in conjunction with the impacts from other past, present, and

reasonably foreseeable projects affecting traditional cultural resources, would have an overall longterm moderate to major adverse impact on traditional cultural resources in the Mariposa Grove area.

Mitigation developed in consultation with traditionally associated tribes and groups would be

applied during project implementation, as described in a project­specific MOA (Appendix G).

Alternative 4: South Entrance Hub with Modified Commercial Tram Service

Alternative 4 would remove the tram staging, gift shop, and the majority of visitor parking from

Mariposa Grove, and would relocate primary visitor parking and tram staging to the new South 

Entrance Hub. New visitor services at the South Entrance area would include visitor information,

educational, and other sales items. The commercial tram would continue to operate on a reduced

schedule and route, originating at South Entrance and extending to the Mariposa Grove Museum,

with stops at the lower and mid­Grove areas. The water tank and chlorination unit on the loop road

in the upper portion of the Grove would be moved to a location near the museum building, and

existing comfort stations at Grizzly Giant and in the upper portion of the Grove would be renovated,

rehabilitated, or replaced. Numerous other repair, renovation, and ecological restoration actions,

such as water line repair or replacement, replacement of the comfort station and installation of a new

septic tank and leach field in the lower Grove area, historic rehabilitation of Wawona Point features,

hydrologic improvements, and soil decompaction and revegetation would be components of this

Final Environmental Impact Statement 3­145 October 2013

Chapter 3: Affected Environment and

Environmental Consequences
             

               

   

         

Cultural Resources: American Indian Traditional Cultural Resources

Restoration of the Mariposa Grove of Giant Sequoias

alternative. An accessible trail would be developed in the lower Grove area, and accessible overlook

at Grizzly Giant would be provided. The intersection of Mariposa Grove and Wawona roads at

South Entrance would be realigned and a roundabout would replace the existing T­intersection if

traffic conditions warrant this action.

Construction­related Impacts. Alternative 4 would affect two archeological sites for which local

American Indians have expressed a vital connection and a desire for better protection from

development and vandalism.  

Construction of a new parking area at the South Entrance would impact nearly half of site

CA­0660/H. In addition, extensive clearing required prior to construction would be a moderate

adverse impact on traditional cultural resources. Actions in the lower Grove area that have the

potential to adversely impact CA­MRP­0661/H include installation of a new shuttle turnaround,

removal of existing roads and parking areas, and ecological restoration of modified areas. Parking

reconfiguration in this area would seek to avoid excavation and rely on use of fill material to avoid

impacting surface features. Black oak trees would be left in place in the vicinity of existing vegetated

island west of the gift shop, and elsewhere where feasible. The main parking area and gift shop at the

lower portion of the Grove would be removed from the vicinity of the site CA­MRP­0661/H.

Impact Significance. Construction activities under Alternative 4 would adversely affect two

archeological sites important to culturally associated American Indian tribes and groups who have

expressed concern about protecting these resources from future development. There is potential for

moderate adverse impacts to site CA­MRP­0660/H from construction of the parking lot at the South 

Entrance. In addition, extensive clearing of the site would be a moderate adverse impact on

traditional cultural resources.   

Impacts on site CA­MRP­00661/H in the lower Grove area would be minor, as design would avoid

ground disturbance and impacts to black oaks in the vicinity of the site. Removal of the parking area

and gift shop away from CA­MRP­0661/H at the lower portion of the Grove would be a beneficial

impact.

Restoration­related Impacts. Ecological restoration activities under Alternative 4 would improve

the overall health of the giant sequoia at Mariposa Grove. These actions, which include increasing

habitat area, reconditioning soils, improving hydrology, reforestation, and prescribed burns, would

enhance values important to American Indians with a cultural association to the Grove, some of

whom are interested in the restoration and preservation of flora and fauna species for traditional

uses. The use of prescribed burns to restore habitat in particular is supported by traditionally

associated American Indians. The Park would work with tribes to improve conditions in the Grove

for flora and fauna species important to American Indian tribes and groups. Alternative 4 restoration

in the lower portion of the Grove would, on the other hand, have adverse impacts on traditionally

significant archeological site CA­MRP­0661/H through recontouring, reconditioning of soils, and

revegetation where facilities have been removed and the planting of native vegetation. These impacts

would be considered temporary adverse impacts.

Impact Significance. Improved giant sequoia habitat through ecological restoration would have a

positive impact on those characteristics of the Grove that are important to the traditionally

associated American Indians by restoring native vegetation, which, in turn, would attract native

fauna. Traditionally significant site CA­MRP­0661/H would be subject to short­term minor adverse

Final Environmental Impact Statement 3­146 October 2013

Chapter 3: Affected Environment and

Environmental Consequences
             

               

   

         

                               

         

               

                             

                       

                   

                         

                             

                       

                             

                                 

                           

                           

                     

                           

                         

  

                   

                     

                               

                             

                 

                       

                         

                         

                           

                         

                     

                       

                               

        

                           

                         

                             

   

                         

                                   

                                 

                                  

                     

                         

    

                           

                           

                           

Cultural Resources: American Indian Traditional Cultural Resources

Restoration of the Mariposa Grove of Giant Sequoias

impacts by restoration actions in the lower portion of the Grove. Revegetation of areas at Wawona

Point also would be beneficial.

Operation­related Impacts. Operations under Alternative 4 would continue to allow traditionally

associated American Indian tribes to have access to the Mariposa Grove and the South Entrance for

traditional practices. There is the potential for continued unauthorized collection of surface

archeological artifacts from sites CA­MRP­0660/H and CA­MRP­0661/H under this alternative.

American Indian tribes and groups traditionally associated with these sites have expressed a desire

that they be protected from vandalism. If construction and operation of a leach field cannot be

designed to avoid impacts to the traditionally significant archeological site (CA­MRP­0661/H), then

vault toilets or a sewer line to South Entrance would be installed instead. Reduced concentration of

visitor parking at the lower Grove area would enhance the natural ambience of the Grove, and thus

enhance the features of the Grove that are important to traditionally associated American Indians.

Also, improved information about native cultures would also occur under Alternative 4. Alternative 4

would provide for additional public information about American Indian traditional culture, which 

would be a beneficial impact. The need for increased public information about American Indian

history and cultural practices has been repeatedly expressed by tribal representatives during project

consultation.

Impact Significance. Potential vandalism is a long­term, minor, adverse impact on significant

traditional cultural resources. Enhanced interpretation of traditional cultural resources and practices

would have a long­term, beneficial impact on these resources at both the lower Grove area and at

South Entrance. Removal of the parking area and gift shop away from CA­MRP­0661/H at the lower

portion of the Grove would be a beneficial impact.

Conclusion. Restoration activities to improve the health of the giant sequoia ecosystem at the

Mariposa Grove would have long­term, moderate to major beneficial impacts on those values

attributed to the Grove by American Indians with cultural associations to the Grove. Alternative 4

would continue to allow traditionally associated American Indians to have access to the Mariposa

Grove and the South Entrance for traditional practices, and the enhancement of visitor education

would enhance the understanding and appreciation of traditional cultural values and archeological

resources at Mariposa Grove. These would be long­term, beneficial impacts. Other beneficial

impacts included removal of the parking area and gift shop away from CA­MRP­0661/H at the lower

portion of the Grove.

Alternative 4 construction actions, including to the removal of structures and paved areas, would

have a long­term, moderate to major adverse impact on archeological site CA­MRP­0660/H. In

addition, extensive clearing of the site would be a moderate adverse impact on traditional cultural

resources.

There would be a short­term, minor adverse impact on archeological site CA­MRP­0661/H. Final

design of facilities in the vicinity of this site would avoid or minimize potential impacts on the site.

Any parking reconfiguration in this area would seek to avoid excavation and rely on use of fill

material to avoid impacting surface features. Mature black oak trees would be left in place in the

vicinity of the site CA­MRP­0661/H and elsewhere where feasible. Traditionally associated

American Indian tribes and groups have specifically expressed concern about future development at

these sites.

Overall, there would be a long­term moderate to major adverse impact on traditional cultural

resources, largely from the loss of site CA­MRP­0660/H at the South Entrance, and the extensive

clearing required as part of the South Entrance parking lot construction. Adverse effects would be

Final Environmental Impact Statement 3­147 October 2013

Chapter 3: Affected Environment and

Environmental Consequences
             

               

   

         

               

                         

                         

                 

                         

                           

                             

                             

                   

                           

                           

                               

                                 

                         

                           

            

                           

                   

                             

                   

                        

                               

                       

                         

                         

                             

             

                       

                     

                         

                

     

                     

                         

                         

                         

                     

                       

                           

                         

      

Cultural Resources: American Indian Traditional Cultural Resources

Restoration of the Mariposa Grove of Giant Sequoias

resolved through consultation with the California SHPO in accordance with the NHPA

implementing regulations at 36 CFR Part 800, and implemented through a project­specific MOA to

be developed in consultation with the SHPO, ACHP, and associated American Indian tribes and

groups.

Cumulative Impacts. The regional past, present, and reasonably foreseeable projects affecting

traditional cultural resources would be the same as those under Alternative 1 (No Action)—an

overall long­term minor adverse impact on traditional cultural resources in the Mariposa Grove area.

Under Alternative 4, there would be a long­term beneficial impact on the giant sequoia ecosystem

with respect to restoration of giant sequoia habitat. The NPS would work with tribes and groups to

improve accessibility to important resources and enhance interpretation of American Indian

traditions and practices in Mariposa Grove. The reduction of automobile traffic within the Grove’s

giant sequoia habitat would improve the overall Grove experience. There would be major adverse

impacts to the historic archeological site at the South Entrance in the lower Grove area, and minor

impacts to the archeological site in the lower Grove area. In addition, the loss of trees required

during construction of the South Entrance parking lot would be a long­term adverse impact on

traditional cultural resources. Overall, there would be a long­term moderate to major impact on

traditional cultural resources under Alternative 4.

The impacts of Alternative 4, in conjunction with the impacts from other past, present, and

reasonably foreseeable projects affecting traditional cultural resources, would have an overall longterm moderate to major adverse impact on traditional cultural resources in the Mariposa Grove area.

Mitigation developed in consultation with traditionally associated tribes and groups would be

applied during project implementation, as described in a project­specific MOA (Appendix G).

ARCHEOLOGICAL RESOURCES

Affected Environment

To date, at least 10 percent of Yosemite National Park lands, including the Mariposa Grove, have

been inventoried for cultural resources, and more than 1,700 archeological sites have been

documented. Most of the inventories have focused on lower­elevation, developed areas and road

corridors, however, some wilderness and higher­elevation areas also have been surveyed. In most

cases, inventories have been conducted in support of park development projects as part of the

environmental and historic preservation compliance processes. The park­wide archeological

research design developed by Hull and Moratto (1999), titled Archeological Synthesis and Research

Design for Yosemite National Park, California, provides guidance for assessing the research potential

of these sites. This document provides the most recent comprehensive overview of Yosemite

National Park’s archeological resources and their informational value.

Yosemite National Park Archeology

Prehistoric archeological sites within Yosemite National Park include lithic scatters and milling

stations (granite boulders with mortar cups or milling slicks), the most common site features

documented to date; artifact caches and scatters (including obsidian waste flakes, obsidian and

ground stone tools, soapstone vessel fragments, and dietary faunal remains); midden soils; rock

shelters; pictograph panels; human burials; house floors; fire hearths; and rock alignments. Historical

archeological sites include refuse deposits, building foundations, privy pits, utilities, human burials,

and landscape features such as ditches, roads, rock alignments, and trails. Individual sites vary by

type, size, depth, complexity, length of occupation, variety of remains, and potential to yield

important scientific information.

Final Environmental Impact Statement 3­148 October 2013

Chapter 3: Affected Environment and

Environmental Consequences
       

               

   

         

                         

                               

                         

                               

                         

                       

                           

                       

                             

                         

    

                         

                           

                           

                     

                         

                         

                         

                       

                               

                       

                               

               

                             

                             

                                 

                         

                       

                           

                                   

                       

                         

                   

                             

                       

                       

                   

               

                 

                   

                       

                   

        

                           

                           

                     

                               

Cultural Resources: Archeological Resources

Restoration of the Mariposa Grove of Giant Sequoias

James Bennyhoff of the University of California at Berkeley presented the first cultural chronology

for prehistoric sites in the park, which was based on his excavations at Crane Flat that were

conducted in the early 1950s (Bennyhoff 1956). Bennyhoff identified three cultural complexes for

the region. Though the dating was tenuous, from oldest to youngest, these were the Crane Flat (circa

A.D. 500), Tamarack (circa A.D. 500­circa 1200), and Mariposa (circa A.D. 1200­circa 1850)

complexes. Since that initial effort to characterize temporal associations of archeological resources

in the park, numerous studies have contributed to improved understanding of the past human

occupation. These studies have included cultural resource management studies within the Park;

overviews of the southern and central Sierra; and excavations of sites at Mariposa Grove, Glacier

Point Road, Dana Meadows, Tuolumne Meadows, Tamarack Flat, Crane Flat, Yosemite Valley, and

El Portal.

Based on the expanded database of archeological information, Hull and Moratto (1999) proposed a

new cultural chronology that reflects the complexity of human occupation throughout the park over

the millennia. The periods of occupation identified by Hull and Moratto (1999:182) include: the

Early Prehistoric (>9500­6000 B.C.), represented by the El Portal and other as­yet­unidentified

complexes or phases; the Intermediate Prehistoric (6000­1200 B.C.), as reflected by the Merced,

Clyde, Wawona, and other unidentified phases; the Late Prehistoric (3500­1200 B.C.­ A.D. 1800),

expressed by the Crane Flat, Cowhorn, Tamarack, Baker, Mariposa, and Klondike complexes; the

Protohistoric (A.D. 1800­1847), representative of the cultural changes in response to the Gold Rush 

and the “discovery” of Yosemite, and identified as the Yosemite phase; and the Historic period (post

A.D. 1848), referred to as the Tenaya complex, which encompasses the ethno­historic period

following the Gold Rush. Hull and Moratto (1999:181) cautioned that “the culture history ... must be

viewed as tentative and subject to revision as archeological research continues.”

Archeological studies conducted at three sites within the area of potential effect established for this

project at South Entrance and in the Mariposa Grove of Giant Sequoias (figure 3­18; Hull 1989)

indicate that the area has been inhabited by American Indians for at least 3,500 years (Bane 2012:5).

Site CA­MRP­660/H, located at the South Entrance, was occupied between 500 A.D. and 1500 A.D.,

while materials recovered at Mariposa Grove sites CA­MRP­199 and CA­MRP­661/H reflect a

different pattern of use. Three periods of occupation were identified at CA­MRP­199; two were

dated between 1500 B.C. and A.D. 500, and the third was from A.D. 1500 to A.D. 1850. The

CA­MRP­661/H deposits, on the other hand, suggest sporadic occupation since 1500 B.C.

Historical archeology is closely tied to the nineteenth and twentieth century development of

Yosemite, beginning with vestiges from early explorers and continuing through NPS management of

the park. In addition to Anglo­American historical use of Yosemite, a subset of historical archeology

represented at the park includes historical American Indian sites. Hull and Moratto (1999:507­510)

present an integrated list of historical archeological resource types documented in Yosemite

National Park that include transportation, exploration and survey, historical Native American,

hunting/trapping, residential, water diversion/use, mine and quarry, logging, ranching/herding/

farming, environmental management, tourism, park operations and administrative, and other types

such as cemeteries. Hull and Moratto (1999:511­531) then developed Yosemite­specific themes

oriented to historical archeology. Themes relevant to the Mariposa Grover ecological restoration

project include transportation, national resource management (e.g., Civilian Conservation Corps),

and industrial (e.g., logging).

During the nineteenth century, the Yosemite area and its natural resources were used and exploited

by individuals for private gain, and included mainly mining, herding, logging, and tourism. The

progression of such development was particularly evident in the transportation and lodging

infrastructure. At the end of the nineteenth century, the area became the first major parcel of federal

Final Environmental Impact Statement 3­149 October 2013

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Cultural Resources: Archeological Resources

Restoration of the Mariposa Grove of Giant Sequoias

land to be set aside for preservation purposes as a result of the movement to preserve the natural

wonders of Yosemite Valley and the Mariposa Grove of Big Trees. Congressional passage of the

Yosemite Grant in 1864 protected the Grove as a state land grant until 1890, when it was designated a

national park by Congress. The creation of this park and its policies on the nature of acceptable land

use fostered tensions between private entrepreneurs, who used public lands for their own profit, and

state and federal governments. These tensions resulted in a number of lawsuits that tested the rights

of private individuals versus the federal government. Ultimately, the federal government prevailed in

preserving Yosemite Valley and the surrounding lands for the public. The preservation of this area

reduced the environmental impacts caused by private enterprises, such as livestock grazing, logging,

cultivation, and mining, within and adjacent to the park.

The historic­era archeology of Mariposa Grove is strongly related to the tourism that developed out

of the establishment of the park, as it was among the initial lands set aside for protection in 1864.

Historic­era archeological remains at South Entrance also reflect tourism after 1932, when the

Wawona Basin was included in the park boundaries. Prior to that date, the area was heavily used as a

center for logging by the Madera Sugar Pine Company, which operated there from 1908 to 1931.

Many of the historic­era archeological sites at South Entrance reflect the lumber industry from that

period.

Mariposa Grove Archeology

Since the mid­1950s, eight cultural resources studies have been conducted at the Mariposa Grove.

These have primarily included archeological surveys (Bennyhoff 1956; Napton and Greathouse 1976;

Hull and Mundy 1985; Jackson 2002; Bane 2012), but limited site test excavation (Hull 1989) and a

cultural landscape inventory (Caywood and Homstad 2004a) have also been completed. The

Mariposa Grove Archeological District, which was listed in the National Register in 1980, was

established as the result of some of the earliest studies (NPS 1980b). The Mariposa Grove

Archeological District consists of three noncontiguous areas (Areas 1 through 3) ranging in size from

10 acres (Areas 1 and 3) to 15 acres (Area 2) that surround three discrete prehistoric archeological

sites with bedrock mortars. These include sites CA­MRP­198 (Area 1), CA­MRP­199 (Area 2), and

CA­MRP­372 (Area 3). Altogether, 21 archeological resources have been recorded within Mariposa

Grove: 4 prehistoric archeological sites, 15 historic­era sites, and 1 multicomponent site that contain

both prehistoric and historic­era constituents (table 3­9).

Nine of the 21 sites have been evaluated for National Register eligibility; the remaining 12 sites have

not yet been evaluated, as summarized in table 3­9. Four of the historic­era sites (CA­MRP­2109H,

P­22­002384, P­22­002385, and P­22­002386) are small, diffuse trash scatters adjacent to the

Mariposa Grove Road, and likely represent single episodes of discard from the road shoulder. The

NPS (Bane 2012) evaluated these sites and recommended that they be considered ineligible for

listing in the National Register, as they do not meet any of the eligibility criteria. The California

SHPO concurred with a determination of ineligibility for these four sites in February 2013. Hull

(1989) conducted test excavations at multicomponent site CA­MRP­661/H in 1985, and

recommended the site as eligible for inclusion in the National Register. Hull also conducted test

excavations at prehistoric site CA­MRP­199 in 1985, and, as noted above, this site is National

Register­eligible as part of the Mariposa Grove Archeological District. CA­MRP­1618H, the

Mariposa Grove Road, also is considered eligible for the National Register as a contributing element

of the Mariposa Grove Historic District. This historic feature extends between Mariposa Grove and

its intersection with Wawona Road at South Entrance.

Final Environmental Impact Statement 3­150 October 2013

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Table 3­9 – Mariposa Grove Archeological Resources

Site Number Site Type

National Register of

Historic Places Eligibility

CA­MRP­198 Prehistoric Eligible*

CA­MRP­199 Prehistoric Eligible*

CA­MRP­372 Prehistoric Eligible*

CA­MRP­661/H Multi­Component Eligible

CA­MRP­662 Prehistoric Not evaluated

CA­MRP­1611H Historic­Era Not evaluated

CA­MRP­1612H Historic­Era Not evaluated

CA­MRP­1613H Historic­Era Not evaluated

CA­MRP­1614H Historic­Era Not evaluated

CA­MRP­1615H Historic­Era Not evaluated

CA­MRP­1616H Historic­Era Not evaluated

CA­MRP­1617/H Historic­Era Not evaluated

CA­MRP­1618H Historic­Era Eligible

CA­MRP­1843H Historic­Era Not evaluated

CA­MRP­2109H Historic­Era Not Eligible

P­22­002376 Historic­Era Not evaluated

P­22­003284 Historic­Era Not Eligible

P­22­003285 Historic­Era Not Eligible

P­22­003286 Historic­Era Not Eligible

P­22­003287 Historic­Era Not evaluated

YOSE 1998 W­02 Not evaluated

* = Site is a contributor to the Mariposa Grove Archeological District

South Entrance Archeology

The South Entrance area has been subject to seven cultural resources studies: 6 archeological surveys

(Hull and Mundy 1985; Hull and Hale 1997; Jackson 2002; Peabody and Bevill 2009; URS n.d.; Bane

2012), 1 limited site test excavation (Hull 1989), and a cultural landscape inventory (Caywood and

Homstad 2004b). Ten archeological sites (8 historic­era, 2 multicomponent,) have been recorded in

this area (table 3­10). Hull (1989) recommended CA­MRP­660/H as eligible for the National Register

after conducting test excavations at the site in 1985. As previously noted in table 3­9, the Mariposa

Grove Road (CA­MRP­1618H) was determined eligible for the National Register as a contributing

element of the Mariposa Grove Historic District. The remaining 8 sites, including CA­MRP­1620H,

the Washburn Wagon Road, is currently under evaluation for National Register eligibility.

Table 3­10 – South Entrance Archeological Resources

Site Number Site Type

National Register of

Historic Places

Eligibility

CA­MRP­660/H Multi­Component Recommended Eligible

CA­MRP­716H Historic­Era Not evaluated

CA­MRP­1361H Historic­Era Not evaluated

CA­MRP­1618H Historic­Era Eligible

CA­MRP­1620H Historic­Era Recommended Eligible

CA­MRP­1850/H Multi­Component Not evaluated

CA­MRP­2105H Historic­Era Not evaluated

CA­MRP­2107H Historic­Era Not evaluated

CA­MRP­2108H Historic­Era Not evaluated

CA­MRP­2110H Historic­Era Not evaluated

Final Environmental Impact Statement 3­151 October 2013

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Environmental Consequences

Impact/Effects Assessment Methodology. Historic properties, as defined by the implementing

regulations of the NHPA, are any districts, buildings, structures, sites, or objects eligible for inclusion

in the National Register because they are significant at the national, state or local level in American

history, architecture, archeology, engineering, or culture. Historic properties also include resources

considered by American Indians to have cultural and/or religious significance. The term “eligible for

inclusion” includes both properties formally determined eligible and all other properties that meet

National Register listing criteria.

Effects on archeological resources considered eligible for inclusion in the National Register were

analyzed in accordance with 36 CFR 800.5(a)(1) effects criteria. Archeological sites are most often

determined eligible for the National Register under 36 CFR 60.4, Criterion (d), as resources that have

“yielded, or may be likely to yield information important in prehistory or history.”

Adverse effects result when it is determined that a proposed action would diminish the

characteristics that make a historic property eligible for inclusion in the National Register. For

archeological sites, these actions generally include physical destruction of, or damage to, all or part

of the property.

National Historic Preservation Act Methods for Assessing Effect. Pursuant to Director’s

Order 12 (Sections 2.14(6)(3), 6.2 F, and 6.3 F and Appendix 3); 40 CFR 1508.7, 1508.8, and 1508.27;

and 36 CFR 800.8), effect intensity, duration, context, and type as they relate to historic properties,

are determined using the criteria established in 36 CFR Part 800. When the effect of an action results

in an alteration of the characteristics of a cultural resource that qualify it for inclusion in the National

Register as a historic property, the action is considered to have an adverse effect under Section 106

of the NHPA. Per 36 CFR 800.5(a)(1), an adverse effect is found when an undertaking may alter,

directly or indirectly, any of the characteristics of a historic property that qualify the property for

inclusion in the National Register in a manner that would diminish the integrity of the property's

location, design, setting, materials, workmanship, feeling, or association. 

The cultural resources investigations and reports for the project were undertaken in accordance with 

the NHPA Section 106 implementing regulations, 36 CFR 800, Protection of Historic Properties. As

amended, Section 106 of the NHPA requires federal agencies with either direct or indirect

jurisdiction over a proposed undertaking to take into account the effect of the undertaking on

historic properties. As part of Section 106 compliance, a four­step process is typically implemented,

and consists of the following: initiate consultation (36 CFR 800.3); identify historic properties

(36 CFR 800.4); assess adverse effects (36 CFR 800.5); and resolve adverse effects (36 CFR 800.6).

These steps involve a range of activities, such as defining the undertaking, identifying the proper

consulting parties (e.g., SHPO and American Indian tribes and groups), delineating the APE,

identifying and evaluating properties in the APE, applying the effects criteria, and resolving any

adverse effects.

Under this four­step process, there are three possible effects determinations:

No Historic Properties Affected – A “no historic properties affected” determination indicates that

no historic properties are in the APE, or that there are historic properties in the APE, but the

undertaking would not alter the characteristics that qualify it for inclusion in or eligibility for the

National Register.

Final Environmental Impact Statement 3­152 October 2013

Chapter 3: Affected Environment and

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Cultural Resources: Archeological Resources

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No Adverse Effect – A “no adverse effect” determination indicates that there would be an effect on

the historic property by the undertaking, but the effect does not meet the criteria of adverse effect in

36 CFR 800.5(a)(1) and would not alter any of the characteristics that make it eligible for listing in the

National Register in a manner that would diminish the integrity of the historic property.

Adverse Effect – An adverse effect indicates that the undertaking would alter, directly or indirectly,

any of the characteristics that qualify it for inclusion in the National Register in a manner that would

diminish the integrity of the property.

Adverse effects may be resolved by developing a memorandum of agreement or programmatic

agreement among the project proponent, the SHPO, and the ACHP, and in consultation with 

associated American Indian tribal governments and traditionally affiliated groups, and other

consulting parties, such as American Indian tribes (36 CFR 800.6). The agreement would specify the

mitigating actions that must be taken to resolve the adverse effects, and the implementation and

documentation protocols to be followed.

As previously noted (see American Indian Traditional Cultural Resources section, above), impacts

on cultural resources that are deemed ineligible for listing in the National Register are also addressed

under NEPA. NEPA states that, in considering whether an action may “significantly affect the quality

of the human environment,” an agency must consider, among other things, the unique characteristics

of the geographic area, such as proximity to historic or cultural resources [40 CFR 1508.27(3)], and

the degree to which the action may adversely affect districts, sites, linear features, landscapes,

buildings, structures, or objects listed, or eligible for listing, in the National Register, or may cause

loss or destruction of significant scientific, cultural, or historical resources [40 CFR 1508.27].

However, the evaluation of project impacts under NEPA is not the same as the evaluation of those

effects under Section 106. The ACHP stated in the preamble for the revised Section 106 regulations

(ACHP 2001: 49) that the rules contain “no significance or materiality limitations,” such as those

contained in the NEPA that limit most of that statute’s key provisions only to actions that might

significantly affect the environment. In contrast, the ACHP Section 106 rules seek to require agencies

to examine all effects of any intensity, whether or not the effects are significant. Where there is an

alteration of a historic property, any diminishment of any aspect of its historic integrity, however

measured and however great or small, can support a finding of “adverse effect.” As a result, any

reduction in the intensity of an impact through mitigation would not necessarily reduce an adverse

effect to a “no effect.” That is, although actions determined to have an adverse effect under Section

106 and 36 CFR 800 may be mitigated, the effect remains adverse. An adverse effect finding under

Section 106 could be an impact with moderate or substantial intensity under NEPA.

NEPA impacts are evaluated based on the criteria of context and intensity. Context means the

affected environment in which a proposed project occurs. Intensity refers to the severity of the

impact, which is examined in terms of the type, quality, and sensitivity of the resource involved,

location and extent of the impact, duration of the effect (short­ or long­term), and other

consideration of context. Beneficial effects are also considered. When no measurable effect exists,

there is no impact. The intensity of an impact is the degree or magnitude of a potential impact,

described as negligible, minor, moderate, or major. Context and intensity are considered together

when determining whether an impact is significant under NEPA. Thus, it is possible that a significant

adverse effect under Section 106 may still exist when the intensity of the impact is determined to be

negligible or even if the impact is beneficial.

Final Environmental Impact Statement 3­153 October 2013

Chapter 3: Affected Environment and

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Cultural Resources: Archeological Resources

Restoration of the Mariposa Grove of Giant Sequoias

The following defines the impact intensities for those cultural resources within the project area that

are not eligible for listing in the National Register:

•	 Negligible Impact Intensity – the impact would be at the lowest levels of detection, barely

measurable, with no perceptible consequences either adverse or beneficial to the resources.

•	 Minor Impact Intensity – the impact is measurable or perceptible, but it is slight and affects a

limited area of a resource or group of resources.

•	 Moderate Impact Intensity – the impact is measurable and perceptible.

•	 Major Impact Intensity – the impact is substantial, noticeable, and permanent.

Area of Potential Effects

The APE for a federal undertaking under the NHPA is defined at 36 CFR 800.16(d) as “...the

geographic area or areas within which an undertaking may directly or indirectly cause alterations in

the character or use of historic properties, if any such properties exist.” The APE for the current

project includes the Mariposa Grove and South Entrance vicinities, including the transportation

corridor linkages (i.e. the Washburn Wagon Road route and the Mariposa Grove Road) between the

two areas, as depicted in figure 3­18. The APE encompasses the Mariposa Grove Archeological

District, as well as the Mariposa Grove and South Entrance Station historic districts. As described

above, the APE incorporates historic properties, archeological resources deemed ineligible for

inclusion in the National Register, and archeological resources not yet evaluated for National

Register eligibility. In accordance with NPS policy, resources for which eligibility has not been

determined are considered potentially eligible for inclusion in the National Register.

Alternative 1: No Action

Under Alternative 1, current infrastructure, concessioner services and maintenance, and park

management would remain as is. No repair, renovation, or ecological restoration actions, such as

improvement of hydrologic flow and universal access, project­specific prescribed fire and hazardous

fuel reduction treatments, soil decompaction, and improvement of visitor orientation and

interpretation, would be implemented.

Operation­related Impacts. Under Alternative 1, the existing conditions for archeological

resources within the project area would not be altered, including the four sites in the Mariposa

Grove Archeological District. Portions of site CA­MRP­1361/H, which has not yet been evaluated

for National Register eligibility, are currently beneath the parking area at the South Entrance.

Similarly, the existing gift shop and shuttle staging area at the lower portion of the Grove overlie

parts of site CA­MRP­0661/H, which has been found to be eligible for listing in the National

Register. A historic­era artifact scatter associated with this site also is in close proximity to gift shop,

which may result in the unauthorized collection of artifacts by park visitors. Unauthorized collection

is considered an adverse effect. Other current operational impacts that exist within the boundaries of

CA­MRP­0661/H include concessioner parking, picnicking facilities next to the gift shop, burn piles,

and hazard fuel thinning. Furthermore, there is little interpretation of archeological resources within

the Mariposa Grove.

Impact Significance and Determination of Effect. The potential for unauthorized collection of

artifacts at site CA­MRP­0661/H would continue under Alternative 1, and constitutes an adverse

effect on this historic property under Section 106 of the National Register. Portions of

CA­MRP­1361/H lie beneath the existing parking lot at the South Entrance. This site has not yet

been evaluated for National Register eligibility, but is assumed eligible until determined otherwise.

Final Environmental Impact Statement 3­154 October 2013

Chapter 3: Affected Environment and

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Cultural Resources: Archeological Resources

Restoration of the Mariposa Grove of Giant Sequoias

Areas of this site beneath the parking lot currently are protected from further disturbance, and

features adjacent to the parking lot lie outside of areas likely to be subject to disturbance by park

visitors. Alternative 1 would have no adverse effect on CA­MRP­1361/H.

Conclusion. Under Alternative 1, the No Action Alternative, the condition, routine maintenance,

and operations of the Mariposa Grove and the South Entrance would remain unchanged. The

potential for adverse effects through unauthorized collection of artifacts would continue in the

lower portion of the Grove at site CA­MRP­0661/H, and portions of site CA­MRP­1316/H would

remain protected by the parking lot at the South Entrance. None of the other archeological

resources identified in the project APE, including those sites that contribute to the Mariposa Grove

Archeological District, would be impacted under Alternative 1. Routine or emergency repairs that

could occur during concessioner and park operation of Mariposa Grove and South Entrance (e.g.,

repairs to existing septic systems and leach fields or buried utilities; excavation of fire breaks) could

result in disturbance of archeological deposits. The level of effect on such deposits would depend on

the significance of the resource, and the extent and magnitude of the disturbance. There would

continue to be limited interpretation of archeological resources in this area of the park.

Cumulative Impacts. The following cumulative effect discussion on archeological resources

considers the past, present, and reasonably foreseeable actions in the Mariposa Grove area, in

combination with potential effects of Alternative 1 (No Action). Archeological resources in the area

were disturbed in the past by construction, operation, and maintenance activities through time.

There have been eight archeological studies in the Mariposa Grove area and seven studies at the

South Entrance since the mid­1950s. These studies identified a number of sites as eligible for the

National Register, though many sites were not evaluated.

Present and future projects in the Mariposa Grove area with ground­disturbing components and the

potential for archeological effects include: placement of riprap along historic road shoulders after

flood events, Mariposa Grove Comfort Station Log Replacement and Repair, Mariposa Grove

Interpretive Sign Installation, Mariposa Grove Trails and Asphalt Removal, Replace Mariposa Grove

Remote Access Weather Station with Standard Tower, South Entrance Boundary Marker

Stabilization, South Entrance Leach Field Repair, South Entrance Office Reroute Telephone Line,

South Entrance Station Reestablish Exit Lane, South Entrance Safety Improvements, South Entrance

Station Reestablish Exit Lane, South Entrance Traffic Safety Improvements, South Entrance Station

Kiosks Replacement, Tachyon Satellite Equipment Installation. Appendix B describes these projects

in more detail. During project implementation, the NPS avoided adverse effects or otherwise carried

out mitigation to minimize potential effects on cultural resources. With application of mitigation,

which may include consultation, survey, testing, monitoring, and data recovery prior to each project,

adverse effects of these projects were resolved.

Alternative 1 (No Action) would result in no change in the current treatment and management of

archeological resources. Maintenance activities would have no effect on archeological resources, as

appropriate mitigation measures would be enacted. Unauthorized collection of archeological

artifacts from the ground surface by visitors could continue. Overall, there would be no adverse

effects.

In summary, past, present and foreseeable future actions would have a no effect on archeological

resources in the Mariposa Grove area. Under Alternative 1, there would be no adverse effect on

archeological resources in the Mariposa Grove area. Present and future effects, in conjunction with 

the effects of Alternative 1 (No Action), would result in no adverse effects on archeological resources

in the Mariposa Grove area.

Final Environmental Impact Statement 3­155 October 2013

Chapter 3: Affected Environment and

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Cultural Resources: Archeological Resources

Restoration of the Mariposa Grove of Giant Sequoias

Alternative 2: South Entrance Hub (Preferred Alternative)

Alternative 2 would remove the commercial tram operations and reduce the amount of impervious

surfaces and structures in the lower portion of the Grove, while relocating primary visitor parking to

South Entrance. New visitor services at the South Entrance area would include visitor information,

educational, and other sales items. The water tank and chlorination unit on the loop road in the

upper portion of the Grove would be relocated to a nearby location outside of sequoia habitat The

gift shop in the lower portion of the Grove, the existing vault toilets at the Grizzly Giant, and the

existing vault toilet in the upper portion of the Grove (near the old lodge site) would be removed.

Numerous other repairs, renovations, and ecological restoration actions, such as water line repair or

replacement, renovation of the comfort station and installation of a new septic system and leach field

in the lower portion of the Grove, historic rehabilitation of Wawona Point features, and soil

decompaction would be components of this alternative. Visitor orientation would be improved and

interpretation of natural and cultural/archeological resources would be expanded. Modifications to

enhance accessibility would be made at South Entrance parking, the restored lower Grove area and

the Grizzly Giant. The intersection of Mariposa Grove Road and Wawona Road at South Entrance

would be realigned and, if needed, to address congestion, a roundabout could replace the existing

T­intersection.

Construction­related Impacts. Construction of a new parking area at the South Entrance would

impact nearly half of site CA­0660/H, which has been recommended eligible for listing in the

National Register. Modification of the existing South Entrance paved parking lot to serve as a bus

turnaround would impact the southernmost extent of site CA­MRP­1361/H. This site has not been

evaluated for listing in the National Register, and evaluation would be necessary, but until then,

CA­MRP­1361/H is assumed eligible. The portion of the site that would be impacted has been

previously disturbed and contains no intact features or recorded artifacts. Alternative 2 also

proposes to convert the majority of the1.5­mile­long historic­era Washburn Wagon Road,

CA­MRP­1620H, to a pedestrian trail that would lead from the South Entrance to the Mariposa

Grove. The remaining 1,100 feet of the wagon road would be removed during construction of the

proposed South Entrance hub parking lot. The road was identified as a contributing resource to an

amended determination of eligibility for the Mariposa Grove Historic District Determination in

2012.

Actions at the lower portion of the Grove that have the potential to adversely impact CA­MRP0661/H include installation of a new shuttle turnaround, removal of the gift shop and modification of

existing parking areas, and ecological restoration of modified areas. Any parking reconfiguration in

this area would seek to avoid excavation and rely on use of fill material to avoid impacting surface

features. The new proposed trail would be designed to run outside of known historic sites, and data

recovery would be conducted as appropriate during trail construction.

Ground­disturbing activities associated with removal and construction of facilities under

Alternative 2 also would have a potential to disturb previously undocumented archeological

resources and/or archaeological deposits that are not visible on the ground surface. The potential

effect of these activities on such resources would depend on the significance of the resource, and the

extent and magnitude of disturbance of such resource during project implementation. Alternative 2

construction would not affect sites included in the Mariposa Grove Archeological District.

Impact Significance and Determination of Effect. Construction of new parking and the

realignment of Wawona Road at the South Entrance would have an adverse effect on site

CA­MRP­0660/H. The NPS would ensure that installation of a leach field and removal of the gift

shop and appurtenant facilities in the lower Grove area would not adversely affect CA­MRP­0661/H.

Final Environmental Impact Statement 3­156 October 2013

Chapter 3: Affected Environment and

Environmental Consequences
       

               

   

         

                     

                             

                         

                                 

                               

                           

                   

                             

                         

                             

                       

                 

                             

                                     

                           

                               

                 

                     

                           

                                 

     

                       

       

               

                     

                           

                       

                      

                             

                           

                           

                                 

                     

                 

                           

                   

                               

                             

                             

                           

                             

     

Cultural Resources: Archeological Resources

Restoration of the Mariposa Grove of Giant Sequoias

Neither site CA­MRP­1361/H nor CA­MRP­1620H has been evaluated for National Register

eligibility, but until evaluation studies are complete, these resources are assumed to be eligible. The

portion of CA­MRP­1361/H that would be affected by construction has been previously disturbed,

and contains no intact features or recorded artifacts. Portions of the site that would be disturbed by

construction of Alternative 2 components are not likely to contribute to the significance of the site,

and therefore would not result in an adverse effect. Approximately 1,100 feet of the historic­era

Washburn Wagon Road (CA­MRP­1620H) would be removed during parking lot construction,

which would result in an adverse effect on the resource. However, rehabilitation of the remaining

segment of CA­MRP­1620H (between the proposed South Entrance parking lot and the picnic area

along Mariposa Grove Road) for use as a pedestrian trail would restore its circulation function.

Rehabilitation actions, such as clearing deadfall and brush and regarding to arrest erosion, would

have no adverse effect on this linear historic property.

Impacts to site CA­MRP­0661/H would be minor, as design would avoid ground disturbance in the

vicinity of the site. The parking area and gift shop at the lower portion of the Grove are being

removed to specifically move them away from CA­MRP­0661/H. Removal of the parking area and

gift shop away from CA­MRP­0661/H at the lower portion of the Grove would be a beneficial

impact.

Ground disturbance during habitat restoration­related activities (e.g., soil decompaction, drainage

improvements, removal of undesirable plant species, new plantings or transplanting) under

Alternative 2 has the potential to disturb buried archeological deposits that are undocumented. The

level of effect on such deposits would depend on the significance of the resource, and the extent and

magnitude of the disturbance.

Sites associated with the Mariposa Grove Archeological District would not be impacted by

Alternative 2 restoration­related activities.

Operations­related Impacts. Continued public access to sites CA­MRP­0660/H and

CA­MRP­0661/H during the operation of Alternative 2 could potentially lead to unauthorized

collection of surface artifacts by park visitors. Such collection would be considered an adverse effect

on National Register­eligible historic properties. However, Alternative 2 would reduce public access

to CA­MRP­0661/H relative to the Alternative 1, which would be a beneficial action.

Routine or emergency repairs that could occur during operation of Alternative 2 at the Mariposa

Grove and the South Entrance (e.g., repairs to septic systems and leach fields or buried utilities;

excavation of fire breaks) could result in disturbance of archeological deposits, including those that

are not visible on the ground surface. The level of effect on such deposits would depend on the

significance of the resource, and the extent and magnitude of the disturbance.

Impact Significance and Determination of Effect. Unauthorized collection of artifacts potentially

could occur at sites CA­MRP­0660/H and CA­MRP­0661/H as a result of ongoing park and

concessioner operations and visitor use under Alternative 2. Such collection of archeological

materials at resources that are eligible for the National Register would be an adverse effect. Reduced

public access to CA­MRP­0661/H under Alternative 2, relative to Alternative 1, would be a beneficial

action.

Routine or emergency repairs that could occur during operation of Alternative 2 at the Mariposa

Grove and the South Entrance could result in disturbance of archeological deposits. The level of

effect on such deposits would depend on the significance of the resource, and the extent and

magnitude of the disturbance.

Final Environmental Impact Statement 3­157 October 2013

Chapter 3: Affected Environment and

Environmental Consequences
       

               

   

         

                         

                     

                         

                         

                           

                                 

                                 

   

                   

                             

                           

                           

                       

                           

                       

                         

             

                     

                               

                       

         

                             

                         

               

               

                           

                               

                        

                                 

                         

                             

                   

                         

                         

          

                             

                                   

                               

                               

                               

                                 

                               

                                 

                           

                             

Cultural Resources: Archeological Resources

Restoration of the Mariposa Grove of Giant Sequoias

Conclusion. Two archeological sites that have previously been determined eligible for the National

Register would be adversely affected by construction activities under Alternative 2.

CA­MRP­0660/H would be disturbed by development of a new parking lot at the South Entrance,

and the realignment of Wawona Road. Alternative 2 construction actions would have a short­term,

minor adverse impact on archeological site CA­MRP­0661/H. Final design of facilities in the vicinity

of this site would avoid or minimize potential impacts on the site. Any parking reconfiguration in this

area would seek to avoid excavation and rely on use of fill material to avoid impacting surface

features.

Sites CA­MRP­1361/H and CA­MRP­1620H require further evaluation, but are considered eligible

for listing in the National Register for the purposes of this assessment. Because portions of

CA­MRP­1361/H have been previously disturbed and no intact features or artifacts remain in the

proposed construction area, a finding of no adverse effect may be appropriate for this resource

under Alternative 2, pending further evaluation. However, approximately 1,100 feet of the historicera Washburn Wagon Road would be removed by construction of the parking area at South 

Entrance, which would result in an adverse effect on site CA­MRP­1620H. The consolidation and

expansion of visitor education at a South Entrance hub would enhance the interpretation of

archeological resources at Mariposa Grove and at South Entrance.

Temporary, minor adverse impacts on traditionally significant site CA­MRP­0661/H would occur

from restoration actions at the lower portion of the Grove, and there would be increased potential

for operations­related adverse effects on sites CA­MRP­0660/H and CA­MRP­0661/H in the form of

unauthorized collection of surface artifacts.

Actions having no adverse effects under Alternative 2 include the clearing of deadfall and brush from

approximately 1.3 miles of the Washburn Wagon Road (CA­MRP­1620H), reducing public access to

CA­MRP­0661/H, and expanding public information about archeological resources.

Cumulative Impacts. Present and reasonably foreseeable projects affecting archeological resources

would be the same as those under Alternative 1 (No Action)—no adverse effect on archeological

resources in the Mariposa Grove. Under Alternative 2, there would be an adverse effect on site

CA­MRP­0660/H at the South Entrance, adverse effect on site CA_MRP­1620H, to the Washburn

Wagon Road, and may have an adverse effect on site CA­MRP­0661/H in the lower Grove area. The

effects of Alternative 2, in conjunction with past, present, and reasonably foreseeable projects, would

have an adverse effect on archeological resources in the Mariposa Grove area. Adverse effects would

be resolved through consultation with the California SHPO in accordance with the NHPA

implementing regulations at 36 CFR Part 800, and implemented through a project­specific MOA to

be developed in consultation with the SHPO, ACHP, and associated American Indian tribes and

groups.

Alternative 3: Grizzly Giant Hub

Alternative 3 would remove the commercial tram operation and build a new bypass road, including

two new bridges and a new, larger parking lot near the Grizzly Giant outside of giant sequoia habitat.

This alternative would make the Grizzly Giant the primary departure point for visitors to the Grove.

The existing road from Grizzly Giant to Wawona Point would be narrowed and converted to a

hardened trail. A new grove bypass road would be constructed between lower portion of the Grove

and Grizzly Giant and the current road would be removed and vegetation restored. The loop road in

the upper portion of the Grove would be decommissioned and converted into a pedestrian trail. The

parking lot in the lower portion of the Grove would largely be removed and replaced by a

significantly smaller parking lot for ABAAS parking. Additional facilities to be removed from the

lower portion of the Grove include the gift shop, visitor information kiosks, the commercial tram

Final Environmental Impact Statement 3­158 October 2013

Chapter 3: Affected Environment and

Environmental Consequences
       

               

   

         

                                 

                               

                       

                     

                     

                       

                   

                   

                   

                               

                                   

          

                               

                           

                                 

                                 

                               

                         

                       

                                     

                           

                 

                     

                             

                       

                     

         

                     

                             

                             

                         

                       

                     

                               

                           

                   

                 

                     

                           

                           

               

                       

       

Cultural Resources: Archeological Resources

Restoration of the Mariposa Grove of Giant Sequoias

staging area, and the existing comfort station. Other changes at the lower portion of the Grove would
 

include a new trailhead and loop trail that would serve ABAAS visitors, and installation of new
 

comfort station. Visitor orientation would be improved and interpretation of natural and cultural/
 

archeological resources would be expanded. Numerous other rehabilitation and restoration actions,
 

such as improvement of hydrologic flow and universal access, project­specific prescribed fire and
 

hazardous fuel reduction treatments, and soil decompaction, would be components of this
 

alternative. The current South Entrance parking lot would remain as is.
 

Construction­related Impacts. Under Alternative 3, the new Grove bypass road would pass
 

through the center of site CA­0661/H, which is a National Register­eligible property. Development
 

of the ABAAS­compliant accessible parking lot and removal of the gift shop, access road, and parking
 

area in the lower portion of the Grove also could disturb this site. These activities could have an
 

adverse effect on site CA­0661/H.
 

The establishment of new parking lot and bypass road at the Grizzly Giant has the potential to
 

impact site CA­MRP­2109H, a small, diffuse, historic trash scatter. The site has been determined to
 

be ineligible for listing in the National Register, and construction of the new parking lot and new
 

Grove bypass road would have no effect on a known historic property under Section 106 of the
 

NHPA. Impacts on this site under NEPA, however, would be long­term and adverse, but given the
 

site’s lack of significance, the impact would be considered negligible. Modifications to Mariposa
 

Grove Road (CA­MRP­1618H), which is a contributing element of the Mariposa Grove Historic
 

District, also would have an adverse effect on an alignment of the road that was in place by 1879.
 

These effects are more thoroughly discussed in the Historic Structures section of this document.
 

Ground­disturbing activities associated with removal and construction of facilities under
 

Alternative 3 would have a potential to disturb previously undocumented archeological resources.
 

The potential effect of these activities on such resources would depend on the significance of the
 

resource, and the extent and magnitude of disturbance of such resource during project
 

implementation. The Mariposa Grove Archeological District would not be affected by constructionrelated activities under Alternative 3.
 

Impact Significance and Determination of Effect. Alternative 3 construction activities would have
 

an adverse effect on site CA­MRP­0661/H, because construction of the New Grove Bypass Road and
 

ABAAS­compliant parking and removal of facilities in the lower portion of the Grove would directly
 

impact this National Register­eligible site. Site CA­MRP­1618H or Mariposa Grove Road also would
 

be adversely affected because proposed modifications would alter characteristics that contribute to
 

its National Register eligibility. Impacts on CA­MRP­2109H would be site­specific, long­term,
 

negligible, and adverse under NEPA; this site has been determined to be ineligible for the National
 

Register.
 

Ground­disturbing restoration activities related to the restoration of existing bus parking and the gift
 

shop area would impact near­ and sub­surface archeological materials at site CA­MRP­0661/H.
 

Furthermore ground disturbance during habitat restoration­related activities (e.g., soil
 

decompaction, drainage rehabilitation, removal of undesirable plant species, new plantings or
 

transplanting) under Alternative 3 have the potential to disturb archeological deposits that have not
 

been documented. The level of effect on such deposits would depend on the significance of the
 

resource, and the extent and magnitude of the disturbance.
 

Sites associated with the Mariposa Grove Archeological District would not be impacted by
 

Alternative 3 restoration­related activities.
 

Final Environmental Impact Statement 3­159 October 2013

Chapter 3: Affected Environment and

Environmental Consequences
       

               

   

         

                 

                     

                               

                         

                             

                         

                       

                     

                 

                           

                           

             

                           

                           

                             

  

                         

                             

                               

                     

                       

                         

   

                           

               

                         

                       

                      

                 

                           

                               

                           

                     

                           

                     

                     

                           

                       

               

                    

                             

                                 

                               

                                   

                                   

Cultural Resources: Archeological Resources

Restoration of the Mariposa Grove of Giant Sequoias

Operations­related Impacts. Operations­related impacts under Alternative 3 would be the direct

result of construction activities at site CA­MRP­0661/H, which would likely bring previously buried

artifacts to the surface where they could be subject to unauthorized collection by park visitors during

park operations. Such collection is considered an adverse effect. Routine or emergency repairs that

could occur during operation of Alternative 3 at Mariposa Grove and South Entrance (e.g., repairs to

leach fields or buried utilities; excavation of fire breaks) could result in disturbance of

undocumented archeological deposits. The level of effect on such deposits would depend on the

significance of the resource, and the extent and magnitude of the disturbance.

Impact Significance and Determination of Effect. The increased potential for unauthorized

collection of artifacts at National Register­eligible site CA­MRP­0661/H as a result of visitor use

under Alternative 3. Such collection of archeological materials at resources that are eligible for the

National Register would be an adverse effect.

Routine or emergency repairs that could occur during operations under Alternative 3 at Mariposa

Grove and South Entrance could result in disturbance of archeological deposits. The level of effect

on such deposits would depend on the significance of the resource, and the extent and magnitude of

the disturbance.

Conclusion. Alternative 3 would have an adverse effect on archeological site CA­MRP­0661/H as

the result of construction activities proposed for the lower Grove area, including building the new

Grizzly Giant bypass road and the removal of the gift shop and other facilities. Development of

parking near the Grizzly Giant would not impact National Register­eligible archeological resources.

The consolidation and expansion of visitor education at Grizzly Giant would enhance the

interpretation of archeological resources at the Mariposa Grove, which would be a beneficial impact

under NEPA.

Restoration activities could have an adverse effect on CA­MRP­0661/H under Alternative 3, and a

potential increased opportunity for unauthorized artifact collection during post­construction

operations would also be an adverse effect on site CA­MRP­0661/H. There would be site­specific,

long­ and short­term, major adverse impacts on archeological site CA­MRP­2109H under NEPA;

this site was determined to be ineligible for the National Register.

Cumulative Impacts. Present and reasonably foreseeable projects affecting archeological resources

would be the same as those under Alternative 1 (No Action)—no adverse effect on archeological

resources in the Mariposa Grove. Under Alternative 3, there would be no adverse effect on site

CA­MRP­0661/H in the lower Grove area. There would be an adverse effect on site CA­MRP­1618H

(the Mariposa Grove Road) because proposed modifications would alter characteristics that

contribute to its National Register eligibility. The effects of Alternative 3, in conjunction with past,

present and reasonably foreseeable projects, would have an adverse effects on archeological

resources in the Mariposa Grove area. Adverse effects would be resolved through consultation with 

the California SHPO in accordance with the NHPA implementing regulations at 36 CFR Part 800,

and implemented through a project­specific MOA to be developed in consultation with the SHPO,

ACHP, and associated American Indian tribes and groups.

Alternative 4: South Entrance Hub with Modified Commercial Tram Service

Alternative 4 would maintain commercial tram service on a limited route and reduced hours of

operation, and would relocate tram staging and the majority of parking from the lower Grove area to

the South Entrance. The water tank and chlorination unit in the loop road in the upper portion of

the Grove would be moved to a location near the museum building in the upper portion of the

Grove, and the gift shop in the lower portion of the Grove and existing comfort stations at the

Final Environmental Impact Statement 3­160 October 2013

Chapter 3: Affected Environment and

Environmental Consequences
       

               

   

         

                                   

                     

                     

                                 

                         

                             

                         

         

                   

                             

                         

                             

                         

                               

                

                           

                 

                                 

                                 

                         

                                   

                                   

                         

               

                             

                             

                             

                               

                                 

                              

                         

                 

                   

                         

                           

                       

   

                     

                           

                         

                             

                             

                 

                             

                     

Cultural Resources: Archeological Resources

Restoration of the Mariposa Grove of Giant Sequoias

Grizzly Giant and in the upper portion of the Grove would be removed. New visitor services at the

South Entrance area would include visitor information, educational, and other sales items.

Numerous other rehabilitation and restoration actions, such as water line repair or replacement,

replacement of the comfort station and installation of a new septic tank and leach field in the lower

portion of the Grove, historic rehabilitation of features at Wawona Point, and soil decompaction

would be components of this alternative. The intersection of Mariposa Grove and Wawona roads at

the South Entrance would be realigned, and a roundabout could replace the existing T­intersection if

traffic conditions warrant this action.

Construction­related Impacts. Construction of a new parking area at the South Entrance would

affect nearly half of site CA­0660/H, which has been recommended eligible for listing in the National

Register. Modification of the existing South Entrance paved parking lot to serve as a bus turnaround

would impact the southernmost extent of site CA­MRP­1361/H. This site has not been evaluated for

listing in the National Register, and evaluation would be necessary, but until then, CA­MRP­1361/H

is assumed eligible. The portion of the site that would be impacted has been previously disturbed,

and contains no intact features or recorded artifacts.

Alternative 4 also would remove approximately 1,100 feet of the historic Washburn Wagon Road

(CA­MRP­1620H) through construction of the parking lot at South Entrance, and would rehabilitate

the remaining 1.4 miles of the wagon road for use as a pedestrian trail between South Entrance and

the picnic area on the Mariposa Grove Road. The road has not yet been evaluated for National

Register eligibility, but pending evaluation, is assumed eligible. Rehabilitation of this road would

affect the resource, but the effect would not be adverse under Section 106, but removal of 1,100 feet

of the road for parking lot construction would have an adverse effect on the integrity of the road.

Lastly, the consolidation and expansion of visitor education at the South Entrance would enhance

the interpretation of archeological resources at Mariposa Grove and South Entrance.

Actions at the lower portion of the Grove that have the potential to adversely impact CA­MRP0661/H include installation of a new shuttle turnaround, removal of existing roads and parking areas,

and ecological restoration of modified areas. Any parking reconfiguration in this area would seek to

avoid excavation and rely on use of fill material to avoid impacting surface features. The new

proposed trail would be designed to run outside of known historic sites, and data recovery would be

conducted as appropriate during trail construction. The parking area and gift shop at the lower

portion of the Grove are being removed to specifically move them away from CA­MRP­0661/H.

Ground­disturbing activities associated with removal and construction of facilities under

Alternative 4 also could have a potential to disturb previously undocumented archeological

resources. The potential effect of these activities on such resources would depend on the significance

of the resource, and the extent and magnitude of disturbance of such resource during project

implementation. Alternative 4 construction would not affect sites within the Mariposa Grove

Archeological District.

Impact Significance and Determination of Effect. Construction of new parking and the

realignment of Wawona Road at the South Entrance would have an adverse effect on site

CA­MRP­0660/H. Similarly installation of a leach field and removal of the gift shop and appurtenant

facilities at the lower Grove area would have an adverse effect on CA­MRP­0661/H. Adverse effects

on historic properties as a result of implementation of this project alternative would be resolved

through consultation with the California SHPO in accordance with the NHPA implementing

regulations at 36 CFR Part 800, and implemented through a project­specific MOA to be developed in

consultation with the SHPO, ACHP, and associated American Indian tribes and groups.

Final Environmental Impact Statement 3­161 October 2013

Chapter 3: Affected Environment and

Environmental Consequences
       

               

   

         

                     

                             

                         

                                 

                               

                               

                     

                               

                   

                                   

                     

                           

                           

                   

               

                           

                       

                           

                       

       

               

                       

                       

                       

                       

        

                             

                           

                           

                                 

                     

                 

                           

                     

                               

                             

                 

                             

                           

                             

     

                         

                     

                         

Cultural Resources: Archeological Resources

Restoration of the Mariposa Grove of Giant Sequoias

Neither site CA­MRP­1361/H nor CA­MRP­1620H has been evaluated for National Register

eligibility, but until evaluation studies are complete, these resources are assumed to be eligible. That

portion of CA­MRP­1361/H that would be affected by construction has been previously disturbed,

and contains no intact features or recorded artifacts. Portions of the site that would be disturbed by

construction of Alternative 4 components are not likely to contribute to the significance of the site,

and therefore the alternative would not result in an adverse effect. Approximately 1,100 feet of the

historic­era Washburn Wagon Road, CA­MRP­1620H, would be removed during parking lot

construction, which would result in an adverse effect on the site. However, clearance of deadfall and

brush from CA­MRP­1620H between South Entrance and the picnic area along Mariposa Grove

Road for use as a pedestrian trail would restore that segment of the site as a transportation corridor

in the park, which would have no adverse effect on the site.

Ground­disturbing restoration activities related to the restoration of existing bus parking and the gift

shop area could have an adverse effect on near­ and sub­surface archeological materials at site

CA­MRP­0661/H, which could result in an adverse effect. Ground disturbance during habitat

restoration­related activities (e.g., soil decompaction, recontouring, drainage rehabilitation, removal

of undesirable plant species, new plantings or transplanting) under Alternative 4 has the potential to

disturb archeological deposits that are undocumented. The level of effect on such deposits would

depend on the significance of the resource, and the extent and magnitude of the disturbance.

Sites associated with the Mariposa Grove Archeological District would not be impacted by

Alternative 4 restoration­related activities.

Operations­related Impacts. Continued public access to sites CA­MRP­0660/H and

CA­MRP­0661/H during the operation of Mariposa Grove and South Entrance under Alternative 4

would potentially lead to unauthorized collection of surface artifacts by park visitors. Such collection

would be considered an adverse effect on National Register­eligible historic properties. However,

Alternative 4 could reduce public access to CA­MRP­0661/H relative to Alternative 1, which would

be a beneficial effect.

Routine or emergency repairs that could occur during operation of Alternative 4 at the Mariposa

Grove and the South Entrance (e.g., repairs to septic systems and leach fields or buried utilities;

excavation of fire breaks) could result in disturbance of archeological deposits, including those that

are not visible on the ground surface. The level of effect on such deposits would depend on the

significance of the resource, and the extent and magnitude of the disturbance.

Impact Significance and Determination of Effect. Unauthorized collection of artifacts potentially

could occur at sites CA­MRP­0660/H and CA­MRP­0661/H as a result of ongoing park and

concessioner operations and visitor use under of Alternative 4. Such collection of archeological

materials at resources that are eligible for the National Register would be an adverse effect under

Section 106 of the NPA. Reduced public access to CA­MRP­0661/H under Alternative 4, relative to

Alternative 1, would have a beneficial impact under NEPA.

Routine or emergency repairs that could occur during operation of Alternative 4 at the Mariposa

Grove and the South Entrance could result in disturbance of archeological deposits. The level of

effect on such deposits would depend on the significance of the resource, and the extent and

magnitude of the disturbance.

Conclusion. Two archeological sites that have previously been determined eligible for the National

Register would be adversely affected by construction activities under Alternative 4.

CA­MRP­0660/H would be disturbed by development of a new parking lot at the South Entrance

Final Environmental Impact Statement 3­162 October 2013

Chapter 3: Affected Environment and

Environmental Consequences
       

               

   

         

                         

                           

                                 

                                 

                      

                           

                             

                             

                     

                                 

                       

                       

         

                     

                                 

                       

                         

       

                           

                 

       

               

                           

                               

                           

                         

                           

                     

                     

                       

         

   

                                 

                         

                     

                         

                         

                             

                                   

                         

                   

Cultural Resources: Archeological Resources

Restoration of the Mariposa Grove of Giant Sequoias

and the realignment of Wawona Road. Alternative 4 construction actions would have a short­term,

minor adverse impact on archeological site CA­MRP­0661/H. Final design of facilities in the vicinity

of this site would avoid or minimize potential impacts on the site. Any parking reconfiguration in this

area would seek to avoid excavation and rely on use of fill material to avoid impacting surface

features. Sites CA­MRP­1361/H and CA­MRP­1620H would require evaluation, but are considered

eligible for the National Register for the purposes of this assessment. Because portions of CA­MRP1361/H have been previously disturbed and no intact features or artifacts remain in the proposed

construction area, a finding of no adverse effect may be appropriate for this resource under

Alternative 4, pending further evaluation. However, approximately 1,100 feet of the historic­era

wagon road would be removed by construction of a new trail along this route, which would result in

an adverse effect on site CA­MRP­1620H. Improved visitor education would enhance the

interpretation of archeological resources at the Mariposa Grove, which would have a long­term

moderate beneficial impact under NEPA.

Temporary, minor adverse impacts on traditionally significant site CA­MRP­0661/H would occur

from restoration actions at the lower portion of the Grove, and there could be increased potential for

operations­related adverse effects on sites CA­MRP­0660/H and CA­MRP­0661/H in the form of

unauthorized collection of surface artifacts. These actions would have long­term, minor to moderate

adverse impacts under NEPA.

Beneficial impacts under NEPA for Alternative 4 would include the clearing of deadfall and brush 

from CA­MRP­1620H, reducing public access to CA­MRP­0661/H, and expanded public

information about archeological resources.

Cumulative Impacts. Present and reasonably foreseeable projects affecting archeological resources

would be the same as those under Alternative 1 (No Action)—no adverse effect on archeological

resources in the Mariposa Grove. Under Alternative 4, there would be an adverse effect on site

CA­MRP­0660/H at the South Entrance and no adverse effect on site CA­MRP­0661/H in the lower

Grove area. The effects of Alternative 4, in conjunction with past, present, and reasonably

foreseeable projects, would have an adverse effect on archeological resources in the Mariposa Grove

area. Adverse effects would be resolved through consultation with the California SHPO in

accordance with the NHPA implementing regulations at 36 CFR Part 800, and implemented through 

a project­specific MOA to be developed in consultation with the SHPO, ACHP, and associated

American Indian tribes and groups.

SOCIOCULTURAL RESOURCES

VISITOR EXPERIENCE AND RECREATION

Affected Environment

Yosemite National Park, as guided by its enabling legislation and the NPS Organic Act of 1916, has

two interwoven purposes: (1) the preservation of the resources that contribute to Yosemite National

Park’s uniqueness and attractiveness—its exquisite scenic beauty; outstanding wilderness values; a

nearly full diversity of Sierra Nevada environments, including the special­giant sequoia groves; the

awe­inspiring domes, valleys, polished granites, and other evidences of the geologic processes that

formed the Sierra Nevada; cultural resources, especially those relating to the beginnings of a national

conservation ethic; and evidence of the American Indians who lived on the land; and (2) to make the

varied resources of Yosemite National Park available to people for their individual enjoyment,

education, and recreation, now and in the future (NPS 1980a).

Final Environmental Impact Statement 3­163 October 2013

Chapter 3: Affected Environment and

Environmental Consequences
           

               

   

         

                             

                             

                       

                         

                       

                               

                       

                                 

                         

                     

                             

                             

      

                           

                           

                           

                       

                         

                             

     

       

                       

                       

                         

                     

                   

                               

                                 

                               

                                 

                          

                               

                             

                             

                                   

    

                             

                           

                             

                           

                                     

Sociocultural Resources: Visitor Experience and Recreation

Restoration of the Mariposa Grove of Giant Sequoias

Recent visitor surveys taken during the peak summer season indicate that viewing scenery and taking

scenic drives are the two most popular activities within Yosemite National Park with 93 percent and

64 percent of respondents participating in those activities, respectively (NPS 2008). For many

visitors, driving through the park is the primary means for experiencing the spectacular views.

Driving to and within Yosemite National Park is usually a pleasurable experience, contributing to

visitors’ enjoyment of the park. The ability to make informal stops along park roads to take

advantage of the unique and varied scenery contributes to each visitor’s opportunity to experience

the park on his or her own terms. Some visitors, depending on season and arrival time, have

opportunities to stop en route at small visitor contact stations such as the Wawona Information

Station. However, during the peak visitation season, travelers sometimes experience traffic

congestion within the park. Congestion issues are exacerbated near the South Entrance due to traffic

conditions at the intersection at Wawona and Mariposa Grove Roads and the park entrance station

at the South Entrance.

Visitor experiences in Yosemite National Park are highly diverse. Some come simply to see Yosemite

National Park’s icons—its waterfalls and geologic features. Others visit to experience a place they

have found unique, for personal challenges, timelessness, a place and pace different from their dayto­day experiences, or a personal connection with the grandeur or intricacies of Yosemite National

Park. The continuum of visitor experiences extends from highly social to isolated, from independent

to directed, from spontaneous to controlled, from easy to challenging, and from natural to more

urban (NPS 2000b).

Park Recreation and Visitor Services

Yosemite National Park provides a range of recreation opportunities, including sightseeing and

tours, picnicking, walking, hiking, bicycling, stock use, climbing, camping, water activities such as

rafting, swimming, fishing, and winter activities such as cross­country and downhill skiing and

snowshoeing. Camping throughout Yosemite National Park is regulated differently depending on

whether the activity occurs in the developed or wilderness areas.

According to a study of visitors, 54 percent of visitor groups participated in day hiking, and

43 percent noted wildlife viewing or bird watching as an element of their trip. A greater proportion

of park visitors hike during off­peak seasons. Sitting or standing quietly, absorbed in thought or in

awe of one of Yosemite National Park’s majestic views, was found to be basic to the park experience.

Artistic pursuits were also important to the enjoyment of the park (NPS 2010c).

Private vehicles are the predominant means of access to and through the park. Over 84 percent of

visitors arrive by private car, with the remaining arriving on a commercial tour bus, on buses

operated by the Yosemite Area Regional Transportation System, by foot, or by bicycle (NPS 2011h).

While within the park, most visitors (62 percent) use the existing park shuttle service at least part of

the time.

The park or its concessioners provide several visitor services, including but not limited to overnight

lodging, camping, interpretive services and events, retail sales, food service, post office, and shuttle

service. The Wawona area has lodging and food service, shuttle service, campground, picnic area, gas

station, and ranger station. The Mariposa Grove area has parking, shuttle and commercial tram

services, a retail gift shop, museum, and a picnic area, as well as restrooms in the upper and lower

groves.

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Park Orientation and Interpretation

Visitors to Yosemite National Park have a number of

information resources available to plan their visits (figure 3­

26). Yosemite National Park’s website provides information

about trip planning, current conditions, other park resources

and pertinent news. The park’s public information office

mails pre­visit materials to those requesting them by phone or

mail. Yosemite Conservancy and NatureBridge also have

interactive websites, offering more in­depth orientation and

the sale of books and maps. The park also provides assistance

(updated information, publications, and seasonal staffing) to

local, multiagency visitor centers where visitors can stop en

route. Once at park entrance stations, visitors receive park

publications with trip and activity planning information.

During the summer and early fall, information stations in Wawona and Big Oak Flat are staffed to

provide additional assistance. In summer, the Tuolumne Meadows Visitor Center introduces the

area to visitors traveling to this region of the park. Each of these facilities provides a selection of

helpful park guidebooks, maps, and other resources sold by Yosemite Conservancy, a nonprofit

partner of Yosemite National Park.

Park interpreters serve a primary resource preservation role by conveying information and

educational programs to visitors and park/concessioner employees about the importance and

sensitivity of park ecosystems and the relationships among various park resources. This includes

educational programs provided by park rangers and park partners such as NatureBridge. The

interpretive staff provides information to visitors about wilderness resources, wildlife, policies,

regulations, conditions, and trails at information centers, in programs, on roving contact

assignments, and open­air tram tours in Yosemite Valley and at the Mariposa Grove. The primary

information source for recreational opportunities in the park’s wilderness is the wilderness centers

in Yosemite Valley, Tuolumne, Big Oak Flat, and Wawona, which are staffed by wilderness rangers.

A wide range of interpretive programs are available. Throughout Yosemite National Park, NPS

interpreters provide ranger­led walks, talks, and evening programs. Interpreters help visitors

connect to the park and our American heritage. Interpretation also serves as a catalyst for inspiring

visitors to gain a greater understanding of themselves and the world through their park experience.

In summer, rangers also lead multiday High Sierra Camp loop trips in the Yosemite Wilderness area.

Wilderness programs can focus on bears, wildflowers, the natural history of the wilderness, the

hydrologic attributes of the Merced and Tuolumne watersheds, minimum­impact camping

techniques, wilderness safety, park policies, and other related topics. Park partners, including

Yosemite Conservancy and park concessioners, offer guided wilderness trips and a wide range of

interpretive opportunities throughout the park. The Sierra Club and The Ansel Adams Gallery also

provide interpretive opportunities within Yosemite Valley.

Park locations for these orientation and interpretation opportunities include visitor centers, the

Yosemite Museum, the Nature Center at Happy Isles in Yosemite Valley, Parsons Lodge and Soda

Springs in Tuolumne Meadows, the Pioneer Yosemite History Center in Wawona, and the Mariposa

Grove Museum in the Mariposa Grove.

Figure 3­26 – Orientation Sign at Lower

Grove

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Mariposa Grove Setting

Visitor facilities in the Mariposa Grove operate during

snow­free months of the year, typically opening in April or

May and closing in October or November. Park visitor

facilities include comfort stations in the lower and upper

Grove, the Mariposa Grove Museum, paved roads and

unpaved trails, paved visitor parking in the lower Grove,

paved shuttle bus parking, and commercial tram staging

area. Concessioner­operated and maintained facilities at the

Mariposa Grove include the gift/snack shop and the

commercial tram and its ticket booth (figure 3­27). Other

Grove amenities include sitting areas, wayside exhibits, signs, trailheads, drinking fountain, and trash 

containers.

The Mariposa Grove can offer a sense of profound awe and beauty to the visitor. The unique natural

setting can inspire reverence and respect. It can induce contemplation and pleasure. The Mariposa

Grove is part of the “front country” area of the park and provides easy access to a variety of activities

including sightseeing, nature study, horseback riding, and hiking. The lower Grove area is near the

parking lot, shuttle drop­off, commercial tram staging area, and gift/snack shop and is more widely

used. The upper Grove area includes the Mariposa Grove Museum and is accessible by commercial

tram as well as by hiking trail (an 850­foot elevation gain from the lower Grove parking lot to the

museum). Wawona Point is a historic scenic overlook near the upper Grove, and affords dramatic

views of varied topography. There are trail connections from the Mariposa Grove area into

designated wilderness and to the Studhorse trailhead between Wawona and the South Entrance.

Visitation is highest at the Mariposa Grove from Memorial Day through Labor Day. During the

winter, the Mariposa Grove may be used for snow play, skiing, and snowshoeing. During the winter

when heavy snow falls, the Mariposa Grove road is closed and visitors park near the South Entrance

and proceed to the Grove on foot, skis, or snowshoes. The commercial tram does not operate in the

winter.

The tram is operated by a commercial vendor from May through October. The commercial tram

service connects the lower Grove parking lot with the upper Grove, with a 10­minute stop at the

Grizzly Giant on the return trip. Many riders do not remain on the tram for the entire trip. In one

study two­thirds of the tram users ride into the upper Grove, but either hike in the upper Grove, or

to Wawona Point or hike from the Grizzly Giant back to the parking lot. Each tram vehicle can

accommodate up to 40 passengers. Data suggest that between 8 and 12 percent of visitors to the

Grove take the tram during the peak season (Leslie et al. 2012). Multiple commercial trams operate

concurrently between 9:30 a.m. and 5:00 p.m. Over the approximate five­month season, it is

estimated that the commercial trams accommodate approximately 50,000 passengers. Visitors with 

limited mobility can pay to ride the wheelchair accessible tram, or they may follow the tram up to the

museum and then down to the Grizzly Giant in their private vehicles at no cost.

Visitor Use in the Mariposa Grove

Per a visitor survey conducted in 2011, the average stay for visitors in the Mariposa Grove was about

2 hours, and 84 percent of all visitors spent at least part of that time visiting the Grizzly Giant

(74 percent hike and 10 percent arrive by tram), one of the largest trees in the Grove (Leslie et al.

2012). The highest visitation in the lower Grove occurred on the Grizzly Giant Trail from the lower

Grove parking lot, and averaged approximately 2,510 people per weekend day (2,300 per weekday)

in July. Average daily visitor use on the Outer Loop Trail heading toward the Grizzly Giant was

Figure 3­27 – Commercial Tram

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approximately 140 visitors per day (all days), as measured in July 2011. Figures 3­28 and 3­29

illustrate the data gathered for daily trail use over a three­month period in 2011. Use of the Grizzly

Giant and Outer Loop trails heading to the Grizzly Giant Tree sharply increased around 9:00 a.m.

and remained high until about 7:00 p.m. On the Grizzly Giant Trail, usage peaked on average at

around 10:00 a.m. (approximately 240 visitors per hour) and 3:00 p.m. (220 visitors per hour).

Figure 3­28 – Average Daily Total of Inbound Visitors at the Upper Grizzly Giant Counter

Source: Leslie et al. 2012

Figure 3­29 – Average Daily Total of Inbound Visitors at the Outer Loop Trail Counter

Source: Leslie et al. 2012

Note: The Outer Loop Trail counter located near the parking lot shows that very few people hike to the Grizzly Giant via the

Outer Loop Trail.

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About 37 percent of visitors to the Grove spend at least some time in the upper Grove. Most

Mariposa Grove visitors reach the upper Grove by hiking (27 percent), while about 10 percent arrive

on the commercial tram service. There is more than one hiking route to the upper Grove. A counter

placed on a primary path to the upper Grove via the Grizzly Giant and California Tunnel trees found

approximately 740 people hiked that route on weekend days (650 people per weekday) in August.

Peak volume heading toward the upper Grove occurs between 11:00 a.m. and 2:00 p.m. (approximately 150 visitors per hour) for all days (Leslie et al. 2012). During the survey period, visitors

typically spent about 7 minutes at the Grizzly Giant and 5 minutes at the California Tunnel Tree.

Visitor Experience

The upper Grove is quieter and more contemplative compared to the atmosphere of the lower Grove

with its parking lot, commercial services, and larger numbers of visitors (NPS 2011i). A survey was

conducted in 2010 and 2011 to assess crowding standards to understand visitors’ perceptions of and

thresholds for crowding at the Grizzly Giant in the lower Grove. The results are as follows:

•	 Preferred number of people at one time with in a 1,400 square foot area: 7 (density of
 

197 square feet per person)
 

•	 Maximum acceptable number of people at one time: 18 (density of 76 square feet per person)

•	 Maximum number of people the NPS should allow: 20 (density of 69 square feet per person)

•	 Maximum number of people that visitors would tolerate, before going somewhere else: 26

(density of 53 square feet per person).

To provide a sense of the densities that respondents indicated they would accept, figures 3­30 and 3­

31 provide photographs used in the research that illustrated hypothetical use levels.

During 2010, the maximum number of people that survey respondents thought the NPS should allow

(20 people per 1,400­square­foot area) was exceeded at the Grizzly Giant 16 percent of time on the

busiest day (approximately 2,200 people); 12 percent of the time on the 7th busiest day

(approximately 2,010 people); and 2 percent of time on the 50th busiest day (approximately

1,440 people) (Leslie et al. 2012). Public scoping comments related to visitor experience included

suggestions to limit the number of visitors to the Grove as some felt the site was too crowded.

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Figure 3­30 – Grizzly Giant Visitor Use Hypothetical Use Level – 18 people, approximately

77 square feet per person

Source: Leslie et al. 2012

Figure 3­31 – Grizzly Giant Visitor Use Hypothetical Use Level – 24 people, approximately

58 square feet per person

Source: Leslie et al. 2012

Final Environmental Impact Statement 3­169 October 2013

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Visitors to the Grove can be grouped according to various considerations such as interests and

abilities. Table 3­11 presents visitor typologies based on limitations (mobility and time) and

transportation mode, timeframe, relative number of visitors, and representative experiences.

Table 3­11 – Visitor Typologies

Limitations (Mobility & Time)

Transportation Mode

Timeframe Representative Experiences

Limited mobility (including visitors with small

children and wheeled strollers)

Road (and other fully accessible routes)

Varies Trailhead

Road/lower Grove

Paying commercial tram riders and persons with

accessible parking placard in private vehicles

following behind

Road

1.5

hours

Mariposa Grove Road including

Big Trees tour

Moderate limited mobility (such as elders and

people with children) AND visitors with strict time

limitations

Road and some trails (may require some level of

accessibility)

1­1.5

hours

Trailhead

lower Grove

Grizzly Giant and California

Trees

Relatively agile with a moderate amount of time

Road and some trails including a slightly wide

trail loop

1.5­3.5

hours

Grizzly Giant and California

Tunnel trees

Agile with a substantial amount of time

Road and all trails including winter use

3.5 +

hours

upper Grove

Mariposa Museum

Wawona Point

Outer Loop Trail

Trailhead

Interpretive and orientation kiosks are located at the main trailhead in the lower Grove parking lot.

Beyond the parking lot, information often is difficult to find and is not accessible to all visitors. Along

with problems getting to the parking lot due to traffic congestion and limited spaces, visitors who

arrive at the trailhead often feel stressed, disoriented, and time­constrained (Yosemite Conservancy

2012). Public scoping comments related to the trailhead area included suggestions to add picnic

tables and to add a visitor center either at the trailhead or at Fish Camp (just outside the park

boundary to the south). Other scoping comments noted a preference for a natural, wildernessoriented experience in the Grove that would be characterized by no­ or less­intrusive infrastructure

or transportation activities.

Accessibility, Trails, and Signs

Universally accessible routes through the Grove are limited to the paved roadways, which are used

by pedestrians, commercial tram riders, maintenance vehicles, and visitors in private vehicles

displaying an accessible parking placard who follow behind the commercial trams. Besides being

important for accessibility, the road is also used by hikers who become lost or disoriented on the

trails that intersect the roadway, and visitors with time constraints who take the commercial tram to

their destination, and then hike back down the road (Yosemite Conservancy 2012). Only certain

portions of Mariposa Grove Road meet accessibility standards (less than 5 percent grade without

Final Environmental Impact Statement 3­170 October 2013

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resting intervals) for those who wish to get out of their cars. Public scoping comments related to

accessibility include suggestions to maintain or improve accessibility for visitors with mobility

limitations, including use of the commercial tram.

Visitors also use the 10­mile trail system to experience the Grove (figure 3­32 and figure 3­33). From

the trailhead the Grizzly Giant is a steady climb of 0.8 mile, the upper Grove is 1.7 miles, and the

Grove Museum is 1.8 miles. Visitors encounter poorly signed trail junctions and road crossings, and

are often left confused, disoriented, and feeling lost; in fact, they may even miss their planned

destinations (figure 3­34) (Yosemite Conservancy 2012).

Figure 3­32 – Trails of the Mariposa Grove

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Figure 3­33 – Stonework along Mariposa Grove Trail Figure 3­34 – Trail Sign

Public scoping comments related to trails state that signs are inadequate and/or confusing.

Trail users who cross the road and pedestrians on the road may encounter commercial trams. Other

hikers may hear the tram engine noise from many areas within the Grove. The noise from the

commercial tram engine can obscure the quiet, natural sounds of the Grove, such as birds calling or

wind in the tree branches. Commercial trams may cause pedestrians to stop and step off the road.

The commercial tram noise, movement, and emissions from the diesel engines distract the thoughts

and attention of many pedestrian visitors. Although the trams provide access for visitors with limited

mobility, because they are a fee­based service, the commercial trams do not meet requirements for

universal accessibility.

Mariposa Museum and Wawona Point

Destinations in and near the upper Grove include the Grove Museum and Wawona Point. The

museum includes exhibits on ecology and history of the giant sequoias, and books and postcards for

sale. The Wawona Point overlook is the Grove destination farthest from the trailhead, and is at the

end of the road. Wawona Point has broad views of the surrounding mountains, Wawona Dome, and

the meadow at Wawona. The vista is in sharp contrast to the closed­in forest environment with its

massive trees and limited views experienced en route to Wawona Point. The vista is the location of

park­wide communications equipment visible to visitors at the overlook, including propane tanks, a

communication tower, and an equipment shed. The equipment at Wawona Point serves multiple

agencies and their vehicles including the NPS, the concessioner in Mariposa Grove, and cell

companies. Periodic, year­round maintenance access is needed for both Wawona Point and the

Mariposa Grove Museum.

Vehicular Access and Circulation

Transportation­related factors have important effects on visitor use and experience at the Mariposa

Grove, and include vehicular access to the Grove, parking capacity, and shuttle service to the Grove.

It is estimated that about 58.5 percent of visitors to the Grove park their private vehicles at the

Mariposa Grove parking lot (113 car capacity) (Leslie et al. 2012). The remainder of the visitors

typically arrive on a shuttle from either the South Entrance parking area or Wawona Store

(figure 3­35). A 2012 Visitor Use and Transportation Assessment concluded that parking is saturated at

the lower Grove, and Wawona Store during the peak summer visitation season – meaning parking is

at capacity all days of the week (Leslie et al. 2012).

Final Environmental Impact Statement 3­172 October 2013

Chapter 3: Affected Environment and

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Sociocultural Resources: Visitor 

Restoration of the Maripo

Figure 3­35 – Traffic Circulation between Wawona and the Mariposa Grove

Final Environmental Impact Statement 3­173 

Chapter 3: Af

Enviro
           

               

   

         

                                 

                                     

                           

                                         

                                     

                         

                               

                               

                               

                                       

                               

                             

                        

                           

                                 

                           

                               

                             

                           

                               

                                     

                               

                         

                           

                       

                           

                                   

          

                         

                     

                     

     

                       

                         

       

                       

   

                       

                     

    

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Parking reaches capacity at the Mariposa Grove often, and generally early in the day. On a typical

day during the peak summer season, the lot fills and the gate to Mariposa Grove Road is first closed

between 9:00 and 10:00 a.m. During a summer­long sampling period, the gates were closed

52 percent of the day on average. The gate opened and closed an average of 5.5 times a day (Leslie et

al. 2012). When the gates close on the road to the lower Grove, visitors park elsewhere and take a

shuttle to the Grove. Additional parking spaces are available at Wawona and the South Entrance.

Input collected via scoping suggests that some members of the public consider the shuttle wait times

to be excessive and that this negatively affects the visitor experience. During the high use season, the

average wait is 12 minutes to board the shuttle at both Wawona and the Mariposa Grove. According

to a 2011 study conducted by the NPS, 75 percent of all shuttle bus waits are 20 minutes or less.

When the Mariposa Grove Road is closed because the Grove parking lot has reached its capacity,

traffic circulation is challenged near the South Entrance, as visitors must proceed to Wawona to park

their cars, wait for a shuttle bus, and backtrack to the Grove.

South Entrance Setting

The South Entrance to Yosemite National Park is used by visitors for orientation, fee payment, and

as a rest stop. Park visitor infrastructure at the South Entrance include the fee kiosks, parking lot, the

paved Mariposa Grove Road, comfort station, and shuttle stop. Periodic heavy traffic volume during

the summer months leads to a variety of issues. During peak seasons and holidays, visitors commonly

endure long wait times to reach the fee­booth kiosks as traffic backs up to the south along Wawona

Road toward Fish Camp. Upon reaching the fee booth and entering the park, visitors are often

routed away from the Mariposa Grove Road toward Wawona, leading to frustration if the Grove is

on a visitor’s itinerary. If the lower Grove parking lot is full, park concessioner staff must stand at the

junction of the closed Mariposa Grove Road and Wawona Road and use hand signals and verbal

communication to reroute traffic westward, leading to poor traffic circulation and confusion, and

creating safety hazards for concessioner staff. The existing Wawona Road – Mariposa Grove Road

T­intersection and three­way stop further exacerbates traffic congestion. During the off­season, the

visitor experience at the South Entrance is typically more favorable, as park visitors can readily reach 

the fee booth and then drive up to the Mariposa Grove (when the road is snow­free), or toward

Wawona with minimal wait times and traffic.

Environmental Consequences

Impact Assessment Methodology

This analysis addresses transportation and mobility considerations as part of the visitor experience

in accordance with the objectives and guidance in Yosemite’s General Management Plan (NPS

1980a). Assumptions used in evaluating visitor experience and recreation impacts for the alternatives

include the following:

•	 Existing infrastructure has been constructed in response to visitor demands and needs. This

includes roads, trails, turnouts, and viewpoints. Private vehicles are the preferred mode of

travel for most visitors.

•	 Anticipated changes in visitor participation would represent an impact, including changes in

ABAAS­accessible areas.

•	 Anticipated changes in visitor experience quality would represent an impact. Way finding,

sound, visitor crowding, and aesthetic changes are among the potential factors influencing

trip quality.

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•	 Anticipated changes in service level (such as reductions in parking, changes in frequency of

shuttle service, or changes in safety conditions) would represent an impact.

Beneficial impacts would occur as a result of enhanced visitor participation, quality of visitor

experience, and service level. Adverse impacts would occur as a result of reduced visitor

participation, quality of visitor experience, and service level.

Impact Intensity Level Definitions

The impact thresholds are as follows.

Negligible – Impacts would result in no change or little noticeable change to 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 backpackers to

be able to drive to a trailhead).

Moderate – Impacts would change the desired experience appreciably (i.e. changes to one or more

critical characteristics, or appreciable reduction/increase in the number of participants).

Major – Impacts would eliminate or greatly enhance multiple critical characteristics or greatly

reduce/increase participation.

Alternative 1: No Action

Under Alternative 1, current infrastructure, concessioner services, maintenance, and park

management would remain as is. No rehabilitation and restoration actions, such as improvement of

hydrologic flow and universal access, project­specific prescribed fire and hazardous fuel reduction

treatments, soil decompaction, or improvements to visitor orientation and interpretation, would be

implemented.

Operation­related Impacts. Visitor experiences in the Mariposa Grove would remain the same.

Parking would continue to reach capacity in the lower Mariposa Grove parking lot, and about

40 percent of summer visitors would take the shuttle from Wawona or the South Entrance. About

60 percent of visitors would be able to park directly in the lower Grove parking lot. Some visitors

would travel to the Mariposa Grove, find the parking lot full, and backtrack 5 to 7 miles to Wawona

to catch the shuttle (which would return on the same 7­mile route). Visitors could end up parking

1⁄4­mile or more from the Wawona shuttle stop. Visitors with limited mobility could continue to

follow the tram to the Grizzly Giant and museum in the upper Grove area in their private vehicles

(with a placard). Estimates of current daily visitation and projections of use levels under each 

alternative are shown in table 3­12 for a busy summer day.

During the off­season, when the lower Grove parking lot and Mariposa Grove Road are free of

snow, 115 parking spaces would be available for visitors to drive directly to the lower Grove,

including two accessible spaces. Twenty year­round parking spaces would continue to be provided

at the South Entrance.

Pedestrians and hikers in the Grove would continue to be distracted by the commercial tram noise,

motion, and emissions in the vicinity of roads. Trail users would encounter poorly signed trail

junctions and road crossings. The interpretive materials located in the museum in the upper Grove

area would not be available to visitors who only have the time or ability to view the lower Grove area.

Final Environmental Impact Statement 3­175 October 2013

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Impact Significance. Local, long­term, moderate, adverse impacts.

Conclusion. Impacts on visitor use and experience would continue for peak season travelers to the

Mariposa Grove. During peak season, vehicular circulation would continue to be adversely affected

by inadequate parking near the Grove, and about 40 percent of visitors would need to take a shuttle

about 7 miles from Wawona to experience the Grove. Visitors would continue to be distracted by the

commercial tram noise and emissions. During the off­season when the lower Grove parking lot and

Mariposa Grove Road are free of snow, 115 parking spaces would be available for visitors to drive

directly to the lower Grove, including two accessible spaces.

Table 3­12 – Estimated Daily Visitors by Mode of Arrival on a Busy Summer Day

(85th Percentile, Design Day)

Mode of Arrival

Alt 1 –

No Action

Alt 2 – South

Entrance Hub

Alt 3 – Grizzly

Giant Hub

Alt 4 – South

Entrance with

Modified Tram

Parked at Mariposa Grove 2,109 0 3,498 0

Shuttle from Wawona Store 1,401 145 0 145

Shuttle from South Entrance 326 3,815 0 3,815

Tour bus to Mariposa Grove 100 0 450 0

TOTAL VISITORS 3,936 3,960 3,948 3,960

SOURCE: Data analysis by Nelson Nygaard, 2012 and Yosemite National Park staff, 2013.

Cumulative Impacts. The cumulative impacts on visitor experience and recreation discussed in this

section consider the past, present, and reasonably foreseeable future actions in the Mariposa Grove

area (including Wawona) in combination with potential effects of Alternative 1 (No Action). This

analysis considers recreation opportunities, access to recreational sites, visitor facilities and services,

visitor safety, and transportation­related factors. In the past, visitor facilities and services have

changed considerably in the Mariposa Grove area. For example, the NPS removed the historic

campground in the lower Grove area and replaced it with a parking lot that accommodated more

visitors, constructed a gift shop, and added commercial tram operations.

Present and future plans and projects related to visitor experience include the Comprehensive

Interpretive Plan, Mariposa Grove Interpretive Sign Installation, Mariposa Grove Museum Lighting

Installation, South Entrance Leach Field Repair, South Entrance Station Reestablish Exit Lane, and

the South Entrance Traffic Safety Improvements. The South Entrance Station Kiosks Replacement

project will reduce congestion at the South Entrance and confusion at the intersection of the

Mariposa Grove and Wawona Roads. The Scenic Vista Management Plan will restore two views in the

Mariposa Grove, one at the museum and one at the Grizzly Giant. Transportation­related actions

proposed in the Parkwide Traffic Management and Information System, the Transit Passenger

Information System, and Wawona Road Rehabilitation would facilitate travel throughout the park

by alerting visitors to real­time travel conditions.

The Draft Merced Wild and Scenic River Comprehensive Management Plan (Merced River Plan)

proposes to formalize parking at the Wawona store and relocate bus and other parking off the

Wawona Road. Under the preferred alternative in the Merced River Plan, a traffic diversion at the

El Capitan Cross­over would divert traffic away from east Yosemite Valley to other places in the

park when Yosemite Valley reaches visitor capacity. Based on 2011 park visitation levels, the

diversion would take place about four days a year for an average of about 3 hours per diversion

(about 12 hours total). The peak days when visitors are diverted from Yosemite Valley under the

Merced River Plan are likely to be high use days for the Mariposa Grove as well, and visitors could

Final Environmental Impact Statement 3­176 October 2013

Chapter 3: Affected Environment and

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encounter congestion and crowding at the Mariposa Grove and in Wawona. The Parkwide Traffic

Management and Information System and the Transit Passenger Information System would help to

alert the visiting public to areas of congestion, allowing visitors to avoid congested areas on peak

visitation days.

Regional transit would expand under the Merced River Plan; there would be up to12 additional

round­trip regional transit runs on the Highway 41 corridor. Public transit would connect

communities south of Yosemite (such as Fresno and Oakhurst) with the Mariposa Grove, Yosemite

Valley, and other park destinations. Shuttle service between Wawona and Yosemite Valley would be

discontinued in favor of this new service. Overall, past, present, and future projects would have a

long­term minor beneficial impact on the visitor.

Under Alternative 1 (No Action), congestion and confusion would be reduced at the South Entrance

with the South Entrance Station Kiosks Replacement project, but some visitors would continue to

travel to the Mariposa Grove, find the parking lot full, and backtrack to Wawona to catch the shuttle

(which would return on the same 7­mile route). The commercial tram, generator, and parkingrelated sounds from the lower Grove would continue to impact soundscapes. Visitors traveling to

Wawona as a destination could also be impacted as they compete for parking with those taking the

shuttle to the Mariposa Grove. Impacts under Alternative 1 on visitor experience and recreation

would be long­term, moderate, and adverse on peak visitation days.

In summary, past present and future plans and projects would have a local, long­term, minor,

beneficial impact on the visitor experience in the Mariposa Grove area. Under Alternative 1 (No

Action), there would be a long­term moderate adverse impact on the visitor experience and

recreation due to inadequate parking and circulation near the Grove and commercial tram noise,

and emissions within the Grove. Past, present and future impacts, in conjunction with the impacts of

Alternative 1, would result in long­term, minor, adverse effect on the visitor experience and

recreation in the Mariposa Grove area, including Wawona.

Alternative 2: South Entrance Hub (Preferred Alternative)

Alternative 2 would remove the commercial tram operation and the lower Grove parking area and

restore those areas to giant sequoia and wetland habitat. Peak season visitor parking would be

consolidated at the South Entrance, which would be the departure point for visitor access to the

Grove. Numerous other rehabilitation and restoration actions would take place, such as

improvement of hydrologic flow and universal access, soil decompaction, and improvements to

visitor orientation and interpretation.

Construction­related Impacts. Construction at the South Entrance and in the Mariposa Grove

could cause short­term inconvenience for vehicles and pedestrians, and possible temporary closures

of facilities such as trails. Repaving the Mariposa Grove Road to the lower Grove area would cause

15 to 30 minute traffic delays for one summer, as sections of the road are reduced to one­lane traffic.

There would be noise, dust, and motion associated with the construction of the South Entrance

parking area.

Impact Significance. Local, short­term, moderate, adverse impacts.

Restoration­related Impacts. Ecological restoration actions in the Mariposa Grove could cause

short­term inconvenience to vehicular and pedestrian traffic, possible temporary closures of

facilities including trails, and noise and dust associated with restoration activities. In the long­term,

the lower Grove area would change from a busy parking area to a natural giant sequoia grove that

sustains and highlights the large mature giant sequoia trees that currently grow in the parking lot, as

Final Environmental Impact Statement 3­177 October 2013

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well as the native understory and young sequoia trees that would be planted. Visitors would

encounter an intact giant sequoias ecosystem as they first enter the Mariposa Grove, rather than a

parking lot and gift shop. The lower Grove is relatively flat compared with the rest of the Grove, and

travel through this part of the Grove would be relatively easy along the footpaths or the new

accessible trail. Ecological restoration would provide an opportunity for visitors with mobility

impairments to experience the Grove outside of their cars on accessible trails.

Impact Significance. Local, short­term, minor, adverse impacts and long­term, moderate, beneficial

impacts.

Operation­related Impacts. Under Alternative 2, the South Entrance would be the primary

departure point for visitors to the Grove. The NPS would provide a shuttle from the South Entrance

along the 2­mile road to the lower Grove area. Limited shuttles from Wawona would continue

(table 3­12). All visitors during peak visitation periods would park in the new South Entrance parking

hub and take the shuttle into the lower Mariposa Grove area, where they would disembark next to

the restored giant sequoia grove (which currently is a parking lot). This may be perceived as an

inconvenience to some of the 60 percent of visitors who currently drive their personal vehicles

directly to the lower Grove parking lot. However, others may appreciate the shuttle ride as an

opportunity to “shift gears” to the unique environment they are about to visit. The 40 percent of

visitors who currently ride the shuttle from Wawona Store would enjoy a shorter shuttle ride (about

5 miles shorter each way). Some visitors would take advantage of the new hiking trail between the

South Entrance and the lower Grove.

During the off­season, when the Mariposa Grove Road is open and no shuttles are operating, visitors

will be able to access the Grove by either parking in the lower Grove parking area (which is used for

shuttles in the summer) or expanded parking area near the existing picnic area (located about one

mile from the Grove). A combined total of about 80 off­season spaces will be available in these two

areas, a reduction in about 35 personal vehicle spaces from the current off­season parking in the

lower Mariposa Grove. Traffic management may be required during these off­season periods.

Peak season visitors would arrive at the lower Grove in a shuttle that would provide direct access to

the trailhead with its improved interpretation and orientation. Consolidation and reconfiguration of

trails and improved trail signs would improve way finding. Signs at the short section of road below

the Grizzly Giant would encourage visitors to use the pedestrian trail instead of the road and assist in

separating pedestrians from vehicles with accessible parking placards going to the Grizzly Giant.

Overall, visitor safety would be improved as a result of reduced vehicular traffic within the Grove.

Removal of the commercial tram service may have a negative impact on the 10 percent of visitors to

the Mariposa Grove who utilized the service. It would also result in the loss of the audio tour that

accompanies the tram. Those who hike to the upper Grove area would benefit from more

opportunities for solitude because of reduced visitation and enjoy a more natural experience without

the intrusion of the mechanized tram. Reduced visitation to the upper Grove is also likely to reduce

visitor impacts on the ecosystem. Visitors to the lower Grove would experience similar

improvements related to the removal of noise and emissions, particularly in the vicinity of the iconic

Grizzly Giant (see Soundscapes section).

The need for the shuttle system from Wawona would be greatly reduced. This would help alleviate

congestion in Wawona.

Final Environmental Impact Statement 3­178 October 2013

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There would be about 285 private vehicle parking spaces at the South Entrance. As this alternative

accommodates current visitation levels, some visitors could be turned away on peak visitation days

given the demand to visit the Grove and the physical constraints on parking capacity.

Under Alternative 2, the consolidation of arrival and parking facilities at the South Entrance would

enable all visitors to have a more natural experience within the Grove. Facilities at the South 

Entrance and in the lower portion of the Grove would be brought into compliance with ABAAS to

improve accessibility and the visitor experience for all visitors, regardless of their level of mobility.

This would include the addition of ABAAS­compliant trails, comfort stations and vault toilets, and

additional parking spaces at the South Entrance, lower Grove area, and Grizzly Giant. The existing

road and a portion of the parking lot in the lower Grove area would be replaced with an accessible

loop trail, which would allow visitors of all abilities to disperse throughout most of the newly

restored, lower portion of the Grove. Another accessible trail would take visitors past the Grizzly

Giant and California Tunnel Tree to an overlook which would allow visitors to view a portion of the

Grove in a more isolated context. Associated benches, small spurs to viewpoints and interpretive

signs, and slightly wider places in the trail, would offer all visitors places to stop to rest or enjoy the

Grove just outside of the main path of travel. All visitors would be able to experience the giant

sequoias, wetlands and wildlife of the Grove in a much less mechanized and more natural setting,

without the motion, sounds and smells from the existing parking lot adjacent to the lower portion of

the Grove, or from trams driving throughout the Grove. The quieter, more natural visitor experience

would be especially noticeable to visitors with limited time, mobility or with young children who do

not travel far from the shuttle stop or accessible parking spaces. Visitors with accessible parking

placards would be able to drive to and through the Grove in their own vehicles up to the Grizzly

Giant trailhead. Road access beyond the Grizzly Giant would be limited to service vehicles only as

the road would be narrowed to restore these areas.

Impact Significance. Local, long­term minor, adverse impacts and major long­term beneficial

impacts.

Conclusion. Under Alternative 2, visitors during peak visitation periods would park in the new

South Entrance parking hub and take the shuttle into the lower Mariposa Grove area, where they

would disembark into a restored giant sequoia grove (which currently is a parking lot). This would

have an adverse impact on travel and access for peak season visitors who currently drive their

personal vehicles directly to the lower Grove parking lot (60 percent), and a beneficial impact on

visitors who take the shuttle from Wawona (40 percent). Parking when the shuttle is not in operation

would be reduced in the lower Grove area, but a new parking area will be constructed near the picnic

area that will result in about 80 total spaces between the lower Grove area and the picnic area (when

the shuttle is not in operation). All visitors would encounter an intact giant sequoia ecosystem as they

first enter the Mariposa Grove, rather than a parking lot and gift shop, which would be a beneficial

impact. Visitors will also enjoy the beneficial impacts of a more natural soundscape. Construction of

the new accessible trail will provide an opportunity for visitors with mobility impairments to

experience the Mariposa Grove outside of their cars. Overall, there would be minor short­term

construction­related impacts on the visitor experience, and long­term beneficial impacts on the

visitor experience from ecological restoration of the sequoia grove, improvement in soundscapes,

consolidated parking, and reduction in shuttle travel time to the Grove.

Cumulative Impacts. Past, present, and reasonably foreseeable projects affecting the visitor

experience and recreation would be the same as those under Alternative 1 (No Action)—a long­term

minor beneficial effect on the visitor experience and recreation in the Mariposa Grove area,

including Wawona.

Final Environmental Impact Statement 3­179 October 2013

Chapter 3: Affected Environment and

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Transportation projects and other present and future actions would work in conjunction with 

actions proposed in Alternative 2. The new parking area at the South Entrance proposed under

Alternative 2 would substantially decrease the demand for parking in Wawona and reduce driving on

the Wawona Road for Grove visitors who backtrack to the Wawona shuttle if they found the existing

lot at the Grove full. The new parking area at the South Entrance would provide shuttle parking that

is 5­miles closer to the Mariposa Grove than the shuttle parking in Wawona. A shuttle to the

Mariposa Grove would be available for visitors arriving to the South Entrance on public transit. Peak

visitation days, when visitors could be diverted to manage user capacity from east Yosemite Valley

under the Merced River Plan, are likely to be high use days for the Mariposa Grove as well. Based on

2011 park visitation levels, the diversion would take place about four days a year for an average of

about 3 hours per diversion (about 12 hours total). Visitors could encounter times when they would

be diverted from Yosemite Valley and encounter congestion at the Mariposa Grove and in Wawona.

The Parkwide Traffic Management and Information System and the Transit Passenger Information

System would help to alert the visiting public to real­time areas of congestion, allowing visitors to

avoid congested areas on peak days. Overall, Alternative 2 would have a long­term beneficial impact

on visitor experience and recreation from consolidated parking, reduction in shuttle travel time to

the Grove, and improvement in soundscapes from removal of the tram, generator, and sound related

to the Lower grove parking area.

In summary, past, present and future plans and projects would have local, long­term, minor,

beneficial impacts in the Mariposa Grove area. Under Alternative 2, there would be a long­term

beneficial impact on visitor experience and recreation from consolidated parking, reduction in

shuttle travel time to the Grove, and improvement in soundscapes. Past, present and future impacts,

in conjunction with the impacts of Alternative 2, would result in long­term beneficial impacts on the

visitor experience and recreation in the Mariposa Grove area, including Wawona.

Alternative 3: Grizzly Giant Hub

Alternative 3 would remove the commercial tram operation and build a new bypass road, including

two new bridges, and a new parking lot near the Grizzly Giant. This alternative would make the

Grizzly Giant the primary departure point for visitors to the Grove. The current South Entrance

parking lot would remain as is and the lower Grove parking lot would be largely removed; a small lot

of ABAAS­only spaces would be developed, increasing the number of ABAAS­compliant accessible

parking spaces from 2 to 10 in the lower Grove area. Numerous other rehabilitation and restoration

actions, such as improvement of hydrologic flow and universal access, project­specific prescribed

fire and hazardous fuel reduction treatments, soil decompaction, and improvements to visitor

orientation and interpretation, are components of this alternative.

Construction­related Impacts. The nature of the impacts would be similar to Alternative 2 but the

focus of most of the disturbance would be at the Grove itself, instead of at the South Entrance. If the

changes were made all at once, it would be a short­lived but major disruption to movement in the

Grove, and the experience of the Grove. If the construction and rehabilitation was undertaken in

stages, then the overall impact could be long­term, with a sequence of short­term disruptions in

varying sections of the Grove.

Impact Significance. Local, short­ to long­term, moderate, adverse impacts.

Restoration­related Impacts. Similar to Alternative 2.

Impact Significance. Local, short­term, moderate, adverse impacts.

Final Environmental Impact Statement 3­180 October 2013

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Operation­related Impacts. Grove visitors would stage at the new parking area near the Grizzly

Giant, and would not be delayed by taking a shuttle from the South Entrance or Wawona, as would

occur with Alternatives 1, 2 and 4 (table 3­12).

There would be no change in parking capacity at the South Entrance under this alternative. The

addition of 233 parking spaces (including spaces for cars, tour buses, recreational vehicles, and

ABAAS spaces) and the visitor contact facilities at the Grizzly Giant location would respond to the

large proportion of users who want to visit that location. However, some visitors who would be

anticipating a more natural, contemplative, and inspirational setting for their experience may have a

negative perception of the increased level of development at the site. Even though they would not

see the structures, people, and motorized vehicles (including tour buses) as they travel on the trail,

they may still be able to hear and smell them to a certain distance. The reduction of activity that

would occur at the lower Grove area and improvements such as wetland restoration would promote

restoration at the lower Grove and change the nature of the visitor experience there. The existing

Wawona Road – Mariposa Grove Road T­intersection and three­way stop would remain under this

alternative.

As this alternative accommodates current visitation levels, some visitors could be turned away on

peak visitation days given the demand to visit the Grove and the physical constraints on parking

capacity. The lack of shuttle service under this alternative may result in unsafe conditions and

resource impacts if cars are parked along the roadway or in other undesirable locations. Signage or

other traffic management strategies could mitigate unsafe or resource impactful parking practices. It

is expected that all visitors would arrive by car or tour bus under this alternative, which may lead to

vehicular congestion. Visitors may appreciate the direct access to the Grove afforded by locating a

large parking lot at Grizzly Giant, although the expansion of developed infrastructure would change

the visitor experience and perception of the entry to the Grizzly Giant. In addition, the direct access

to Grizzly Giant could promote crowding as more visitors can arrive at the site concurrently, and

nearly all visitors would visit the Grizzly Giant, instead of the 84 percent who currently visit that area

of the Grove. Parking access at the Grizzly Giant would significantly increase visitation to the upper

Grove because it would shorten hiking distance to that area. This would have the benefit of

providing easier hiking access to the upper Grove to more visitors, but the increased access could

result in diminished experiences due to more visitors using the area. Higher visitor use in the upper

Grove could also result in increased impacts on the environment and increased pressure on existing

facilities.

Under Alternative 3, the accessibility of all facilities at the new transportation hub at the Grizzly

Giant would be in compliance with ABAAS. Seven ABAAS­compliant parking spaces would be

available at Grizzly Giant and ten available in the lower portion of the Grove. A 0.3­mile accessible

loop trail would be constructed in the lower portion of the Grove, and a 0.25­mile accessible trail

would be constructed to the Grizzly Giant and California Tunnel Tree. Placarded access to the upper

Grove would be discontinued.

Impact Significance. Local, permanent, minor, adverse impacts; and local, permanent, major,

beneficial impacts.

Conclusion. While both Alternatives 2 and 3 are designed to consolidate parking for Grove visitors,

Alternative 3 would locate this infrastructure closer to the heart of the Grove. In comparison to

Alternative 2, Alternative 3 provides a more auto/personal vehicle­centered option for

accommodating visitors because it is focused on expanding parking closer to the Grove and

eliminating shuttle service. Alternative 3 would reinforce personal vehicle access as the primary

mode of access to the Grove, which some visitors may appreciate, whereas Alternative 2 relies on

Final Environmental Impact Statement 3­181 October 2013

Chapter 3: Affected Environment and

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expanded shuttle service to deliver visitors to the Grove. While some visitors may be more

comfortable navigating the park from their cars, this alternative would serve to introduce the noise,

emissions, and other effects of car use directly adjacent to the most popular visitor destination.

Increased crowding at Grizzly Giant could result from direct access for vehicles and commercial tour

buses to the site. Location of parking at the Grizzly Giant would likely impact other areas of the

Grove as well. Less vehicular travel and visitor use in the lower Grove area could result in higher

quality experiences and lower impacts to resources than exists under Alternatives 1, 2, or 4; however,

the anticipated increased visitor use of the upper Grove could result in a decline in visitor experience

quality and increased resource impacts.

Grove visitors expecting a more natural start to their experience may experience moderate impacts

on the visitor experience due to the change in experience at the Grizzly Giant due to the expansion

of developed infrastructure and overall less perceived naturalness in that location. However, visitors

to the lower Grove area would benefit from reduced infrastructure and a greater perceived natural

experience in that area.

Cumulative Impacts. Past, present, and reasonably foreseeable projects affecting the visitor

experience and recreation would be the same as those under Alternative 1 (No Action)—a long­term

minor beneficial effect on the visitor experience and recreation in the Mariposa Grove area,

including Wawona.

Transportation projects and other present and future actions would work in conjunction with 

actions proposed in Alternative 3. The new parking area at the Grizzly Giant hub would substantially

decrease the demand for parking in Wawona by Grove­bound visitors and reduce driving on the

Wawona Road for Grove visitors who backtrack to the Wawona shuttle if they found the existing lot

at the Grove full. There would be no shuttle service available from Wawona or the South Entrance,

even for visitors arriving to the South Entrance on public transit.

Peak visitation days, when visitors could be diverted from Yosemite Valley under the Merced River

Plan to manage user capacity, are likely to be high use days for the Mariposa Grove as well. Visitors

could encounter times where they would be diverted from east Yosemite Valley and encounter

congestion at the Mariposa Grove and in Wawona. The Parkwide Traffic Management and

Information System and the Transit Passenger Information System would help to alert the visiting

public to real­time areas of congestion, allowing visitors to avoid congested areas on peak days.

Overall, Alternative 3 would have a long­term beneficial impact on visitor experience and recreation

from consolidated parking at the Grove.

In summary, past, present and future plans and projects would have local, long­term, minor,

beneficial impacts in the Mariposa Grove area. Under Alternative 3 there would be a long­term

beneficial impact on visitor experience and recreation from consolidated parking and direct access

to the Grove. Past, present and future impacts, in conjunction with the impacts of Alternative 3,

would result in long­term beneficial impacts on the visitor experience and recreation in the

Mariposa Grove area.

Alternative 4: South Entrance Hub with Modified Commercial Tram Access

Alternative 4 would maintain the commercial tram but with a limited route and hours of operation

while also relocating the majority of the parking to the South Entrance, making the South Entrance

the primary departure point for visitors to the Grove. Numerous other rehabilitation and restoration

actions, such as improvement of hydrologic flow and universal access, project­specific prescribed

fire and hazardous fuel reduction treatments, soil decompaction, and improvements to visitor

orientation and interpretation, are components of this alternative.

Final Environmental Impact Statement 3­182 October 2013

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Construction­related Impacts. Similar to Alternative 2, except that the road between the lower and

upper Grove areas would not be narrowed and converted to a hardened trail.

Impact Significance. Local, short­term, moderate, adverse impacts.

Restoration­related Impacts. Similar to Alternative 2.

Impact Significance. Local, short­term, moderate, adverse impacts.

Operation­related Impacts. Changes to parking and number of visitors served would be similar in

Alternatives 2 and 4 (table 3­12). The only change in travel conditions between Alternative 2 and 4

would be the inclusion of the commercial tram, which would provide an additional mode to access

the upper Grove area for some. The commercial tram would run between the South Entrance and

the upper Grove, providing a non­hiking option for access to the Grizzly Giant and upper Grove

area. The upper Grove tram terminus would also provide a staging area for visitors who want to go to

Wawona Point but would not or could not walk to the overlook from the lower Grove area.

Under this alternative, almost all visitors to the Grove would arrive via shuttle from the South 

Entrance. Limited shuttle service would still be available from Wawona to South Entrance for those

staying overnight in the Wawona area. Visitor use levels and associated impacts in the upper Grove

area would be similar to Alternative 1. A modified Wawona Road – Mariposa Grove Road

T­intersection would slightly improve traffic flow and safety.

The commercial tram noise, motion, and emissions would distract pedestrians on or crossing the

road and at the trailhead, as well as on trails in the vicinity of the road, similar to conditions under

Alternative 1. The slower­moving tram may also adversely impact shuttle operations between the

South Entrance and the lower Grove.

For those with mobility constraints, vehicles with placards would be allowed to follow the tram to

the Grizzly Giant and upper Grove area and have similar access as under Alternative 1. Accessibility

would be improved by constructing an accessible loop trail in the lower portion of the Grove and an

accessible overlook near the Grizzly Giant and California Tunnel Tree.

Impact Significance. Local, permanent, minor, adverse impacts; and local, permanent, moderate,

beneficial impacts.

Conclusion. Impacts on visitor use and experience would be similar to Alternative 2, except

conditions would be somewhat more adverse to pedestrians desiring a more natural, contemplative

and inspirational setting, and somewhat more beneficial to visitors who wish to experience the

Grove on the commercial tram.

Cumulative Impacts. Past, present, and reasonably foreseeable projects affecting the visitor

experience and recreation would be the same as those under Alternative 1 (No Action)—a long­term

minor beneficial effect on the visitor experience and recreation in the Mariposa Grove area,

including Wawona.

Transportation projects and other present and future actions would work in conjunction with 

actions proposed in Alternative 4. The new parking area at the South Entrance proposed under

Alternative 4 would substantially decrease the demand for parking in Wawona and reduce driving on

the Wawona Road for Grove visitors who backtrack to the Wawona shuttle if they found the existing

lot at the Grove full. The new parking area at the South Entrance would provide shuttle parking that

Final Environmental Impact Statement 3­183 October 2013

Chapter 3: Affected Environment and

Environmental Consequences
           

               

   

         

                                   

                           

                             

                                 

                           

                           

                           

                             

                       

                               

                             

                           

                             

                         

                               

                           

             

                         

                     

                           

                 

                         

                         

                   

                 

                           

                             

                 

                   

                     

     

                         

                             

                           

                               

                        

                       

                         

                       

                             

                       

                     

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is five miles closer to the Mariposa Grove than the shuttle parking in Wawona. A shuttle would be

available for visitors arriving to the South Entrance on public transit. Peak visitation days, when

visitors could be diverted from Yosemite Valley to manage user capacity under the Merced River

Plan, are likely to be high use days for the Mariposa Grove as well. Visitors could encounter times

where they would be diverted from Yosemite Valley and encounter congestion at the Mariposa

Grove and in Wawona. The Parkwide Traffic Management and Information System and the Transit

Passenger Information System would help to alert the visiting public to areas of congestion, allowing

visitors to avoid congested areas on peak days. Overall, Alternative 4 would have a long­term

beneficial impact on visitor experience and recreation from consolidated parking, reduction in

shuttle travel time to the Grove, and improvement in soundscapes from removal of the generator and

sound related to the Lower grove parking area, though sounds related to the commercial tram would

remain.

In summary, past, present, and future plans and projects would have local, long­term, minor,

beneficial impacts in the Mariposa Grove area. Under Alternative 4, there would be a long­term

beneficial impact on visitor experience and recreation from consolidated parking, and reduction in

shuttle travel time to the Grove. Past, present and future impacts, in conjunction with the impacts of

Alternative 4, would result in long­term beneficial impacts on the visitor experience and recreation

in the Mariposa Grove area, including Wawona.

PARK OPERATIONS

Affected Environment

Sound park operations help maintain a safe, functional, and orderly environment that provides

compatible opportunities for resource preservation and enjoyment by visitors and employees to

Yosemite National Park. The park supports an integrated system of compatible land uses providing

opportunities for recreation, community development, preservation, and economic use of resources.

NPS Resource Management and Science staff are responsible for protecting the natural and

sociocultural resources of the park. The NPS Division of Facilities Management performs preventive

and corrective maintenance on utility infrastructure throughout the park, which includes water

supply systems, wastewater disposal infrastructure, power systems, telecommunications systems,

and roads and parking lots. The NPS Divisions of Visitor Protection, Interpretation and Education,

and Facility Management maintain a physical or operational presence at the Mariposa Grove and the

South Entrance. NPS law enforcement rangers perform essential functions and responsibilities,

including law enforcement and resource protection, search and rescue, emergency medical

response, wilderness management, and oversight of concession services at the Grove.

Mariposa Grove Setting

Mariposa Grove visitor facilities are operated seasonally during snow­free months of the year,

typically opening in April or May and closing in October or November. Park facilities and

infrastructure within the Mariposa Grove include comfort stations in the lower and upper Grove

areas, a small office and storage area, the Mariposa Grove Museum, two water tanks, paved roads

and unpaved trails, paved shuttle bus parking, and commercial tram staging area.

Concessioner­operated and maintained facilities at the Mariposa Grove include the gift/snack shop

and its diesel­powered generator, and commercial tram ticket booth. Other Grove amenities include

sitting areas, wayside exhibits, signs, trailheads, drinking fountain, and trash containers. The park

owns the shuttle buses and commercial trams that serve the Mariposa Grove (figure 3­36); Delaware

North Companies operates and maintains the shuttle buses and commercial trams. The NPS

Division of Facilities Management maintains the roads, parking lot, and all non­concessionerFinal Environmental Impact Statement 3­184 October 2013

Chapter 3: Affected Environment and

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Sociocultural Resources: Park Operations

Restoration of the Mariposa Grove of Giant Sequoias

operated buildings throughout the Grove. The park also

maintains the communications systems and associated solar and

propane generator power systems, scenic overlook, and

comfort station at Wawona Point.

A domestic water supply system constructed in the 1930s

supplies water to the upper Grove area, lower Grove area, and

the South Entrance and is a designated alternate water source to

the community of Wawona. A water line from the upper Grove

settling tank to a hydrant near Mariposa Tree and Rattlesnake

Creek is approximately 2700 feet in length and is leaking in

several areas, resulting in a loss of water of 27.5 gallons per

minute. The 450­foot water line segment from the hydrant at

Mariposa Tree leaks at joints and pin holes at various locations

throughout Rattlesnake Creek. Static tests show leakage rates at 1.5 gallons per minute through the

creek bed. Over the years many repairs have been made on the water lines throughout the system but

leaks remain. In addition to maintenance activities on the lines of the water supply system, the water

tanks were replaced at the South Entrance and the lower Grove area in 2007­2008.

Delaware North Companies Parks and Resorts at Yosemite, Inc. is currently Yosemite National

Park’s primary concessions contractor, providing lodging, retail, food and beverage, commercial

recreation, and transportation services to visitors at Yosemite National Park. Delaware North 

Companies is the only concessioner operating in the Mariposa Grove. Delaware North Companies is

responsible for operating and maintaining the park shuttle buses, commercial trams (4 at Mariposa

Grove and 3 in Yosemite Valley), and the Grove gift shop from May through October. Concessioner

staff also assist with traffic management when the lower Grove parking lot is full.

South Entrance Setting

Park facilities at the South Entrance include a single­story ranger building, garage, entrance office,

kiosk, parking lot, the paved Mariposa Grove Road, comfort station, and shuttle stop. Infrastructure

systems at the South Entrance include a water supply and distribution system, and a leach field septic

system. Power to the comfort station and ranger residence is provided by Pacific Gas and Electric

Company via above­ and below­ground electrical lines. The ranger building also has a satellite dish,

propane­powered generator, propane tanks, hazardous materials storage, and electrical transformer.

The South Entrance operates year­round, and is staffed by NPS rangers; no concession services

other than the shuttle stop are provided at the South Entrance.

Transportation and Public Safety

The current configuration of the Wawona Road/Mariposa Grove Road T­intersection at the South 

Entrance has resulted in inefficient traffic flow as well as safety concerns for motorists and

pedestrians using or passing through the area. Inadequate road design, width, striping, and signs

were noted by the public during the scoping period. These concerns are documented in the 2011

Parkwide Safety Study/Review Report which indicates that this intersection now has the highest

overall accident index in the park (given completion of work at the Chinquapin intersection). Due to

the limited parking at the Grove, its popularity, and overall high visitation of the park, the Mariposa

Grove Road is periodically closed by concessioner employees who must reroute motorists, using

hand signals, to Wawona. The congestion and resultant confusion is not optimal for public safety or

the visitor experience. A turn­off lane was constructed heading southward through the South 

Entrance toward Fish Camp to alleviate traffic congestion. Separate NPS modifications to the kiosk

area at the South Entrance are expected to improve circulation at the intersection by allowing

Figure 3­36 – Park Shuttle Bus

Final Environmental Impact Statement 3­185 October 2013

Chapter 3: Affected Environment and

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Sociocultural Resources: Park Operations

Restoration of the Mariposa Grove of Giant Sequoias

visitors the space to select a right or left turn lane. The design for the Restoration of the Mariposa

Grove of Giant Sequoias includes additional long­term plans for improving transportation, traffic

flow, and pedestrian and motorist safety in this area, if needed.

Environmental Consequences

Impact Assessment Methodology

Impacts on park operations were considered to determine how each alternative would affect park

management strategies, methods, and costs.

Impact Intensity Level Definitions

Negligible – Impacts on park operations would be largely unnoticed by staff and the visiting public.

Existing programs and activities would remain essentially unchanged. There would not be a

measurable difference in costs from existing levels.

Minor – Park operations would be affected, but the impacts would be limited and not generally

noticed by visitors. Increases or decreases in operating costs and staffing workload would require

some realignment of funds, but would not require substantial changes to the overall operating

budget. Measurable additions or reductions in cost would be less than 10 percent of existing levels.

Moderate – Park operations would be measurably affected, and the impacts would be noticeable to

some visitors. Increases or decreases in operating costs and/or workload would require realignment

of funds and would alter the scope and/or quality of some programs. Additions or reductions in cost

would be between 10 percent and 20 percent of existing levels.

Major – Impacts on park operations would be widespread and readily apparent to most visitors.

Increases or decreases in operating costs and/or workload would require substantial changes in

funding allocation and alter the scope and quality of multiple programs or basic operational

activities. Additions or reductions in cost would exceed 20 percent of existing levels.

Type of Impact. Impacts were evaluated as either beneficial or adverse to park operations. Adverse

impacts represent an increase in operating costs or management activities, and beneficial impacts

represent a decrease in operating costs or management activities.

Alternative 1: No Action

Operation­related Impacts. Under the No Action Alternative, the Mariposa Grove would remain in

its existing condition and park operations and management would not change. The dispersal of

facilities and equipment and the aging infrastructure within the Grove would continue to require

ongoing maintenance and repairs and increased facilities management time, staff, and resources.

The existing septic system at the South Entrance and restroom facilities throughout the Grove would

continue to be inadequate and the wastewater system would continue to generate odor complaints

and service calls. The leaking water supply line from the upper Grove area to the hydrant near

Mariposa Tree and Rattlesnake Creek would not be replaced, resulting in more maintenance costs

for repairs. The deteriorating alternative Wawona water supply system would not be repaired and

the water tank would remain adjacent to the upper Grove loop. Water system operators would

continue to be challenged with repairing and rehabilitating an already degraded and deteriorated

water system.

Final Environmental Impact Statement 3­186 October 2013

Chapter 3: Affected Environment and

Environmental Consequences
   

               

   

         

                           

                         

                         

                       

       

           

                         

                             

                             

       

                     

                       

                           

                         

                       

             

                       

                     

                 

                         

                       

                     

                                   

                     

                           

                         

                           

                   

                           

                             

                         

                           

   

                           

                          

              

                 

                       

                           

                           

                                 

                        

         

Sociocultural Resources: Park Operations

Restoration of the Mariposa Grove of Giant Sequoias

Under the No Action Alternative, buildings, structures, and roads would not be upgraded or

replaced, which could result in ongoing repair and maintenance work. The park would continue to

operate the shuttles between Wawona, the South Entrance, and lower Grove area from May through 

October. The park would continue to collect franchise fees generated by the concessioner­operated

tram and gift shop.

Impact Significance. Local, long­term, moderate, adverse impact.

Conclusion. The aging buildings and infrastructure at the Grove would continue to place demands

on facilities management staff for repair and maintenance work, resulting in overall increases to the

operating budget. Under the No Action Alternative, the Grove would have an adverse impact on

park operations and facilities.

Cumulative Impacts. This cumulative impact analysis on park operations considers the past,

present, and reasonably foreseeable future actions in the Mariposa Grove area, in combination with 

potential effects of Alternative 1. Past park operations have a negligible impact on the operational

conditions of today. Development of the Parkwide Traffic Management and Information System, the

Transit Passenger Information System, and completion of the Wawona Road Rehabilitation may

reduce traffic­related operational burdens by contributing to transportation management solutions

within the park. Completion of the Parkwide Communication Data Network could improve

operational efficiency through faster and more secure network capabilities, while reducing the

demand on existing telecommunications infrastructure. The Wawona Meadow Restoration project

may reduce the operational burdens of future restoration efforts in this area. The South Entrance

Station Kiosk Replacement could enhance traffic flow and reduce congestion at the South Entrance,

thereby reducing the park’s overall transportation management burdens. In the future, park

visitation is expected to continue growing at the present rate of 3 percent annually. As a result, the

operational burden associated with managing large numbers of park visitors, including those

associated with the provision of visitor services; the management of park resources; and the demands

on and maintenance of administrative facilities, employee housing, and utilities; among other aspects

of park operations would continue to increase. Present and future operational plans and projects

would have a long­term minor beneficial impact on park operations.

Alternative 1 (No Action) does not propose changes to existing park and concessioner operations

and facilities. Aging buildings and infrastructure at the Grove would continue to place demands on

facilities management staff for repair and maintenance, resulting in overall increase in time and

staffing. There would be a local, long­term moderate adverse impact on park operations under

Alternative 1.

The long­term minor beneficial impact of past, present, and future actions, in conjunction with the

long­term moderate adverse impacts of Alternative 1, would be long­term, minor, and adverse.

Alternative 2: South Entrance Hub (Preferred Alternative)

Construction­related Impacts. Alternative 2 would have temporary, short­term, and minor adverse

impacts on facilities management staff and park operations during the construction phase.

Additional demands would be placed on park staff to coordinate construction activities and visitor

use, and construction work and traffic delays would disrupt normal traffic patterns, parking, and

visitor activities. The park would need to take additional measures to notify visitors of the status of

the roads, potential traffic delays, and the location of designated parking areas.

Impact Significance. Local, short­term, minor, adverse impact.

Final Environmental Impact Statement 3­187 October 2013

Chapter 3: Affected Environment and

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Sociocultural Resources: Park Operations

Restoration of the Mariposa Grove of Giant Sequoias

Restoration­related Impacts. Restoration of the Mariposa Grove would not interfere with or

impact park operations. Existing operations and activities would remain essentially unchanged.

Impact Significance. Local, short­term, negligible impact.

Operation­related Impacts. Under Alternative 2, the commercial tram would be removed, lower

Grove parking would be reduced, and primary visitor parking would be relocated to the South 

Entrance. Some Grove facilities and infrastructure would be removed and consolidated at the South 

Entrance to improve access and serviceability. Restrooms would be added, the existing water supply

system repaired, and a new septic system would be installed. The consolidation of parking at the

South Entrance, in conjunction with the support of traffic management staff, would improve traffic

flow and reduce back­tracking and confusion by visitors. Alternative 2 would reduce the need for

continual maintenance repairs to deteriorating utility infrastructure; however, the addition of new

facilities and infrastructure and more complex utility systems would offset the savings. Alternative 2

would consolidate visitor education at the South Entrance indoor/outdoor visitor contact area,

which would include interpretive program elements.

The NPS would need to increase the number of bus hours of the Mariposa Grove shuttle by about

35 percent under Alternative 2, with a proportional increase in transit costs. This estimate considers

the reduced shuttle service between Wawona and the lower Grove area, additional service between

the South Entrance and the lower Grove area, and expansion of shuttle operations into the shoulder

seasons.

Elimination of the commercial tram service would result in a local adverse impact on the existing

concessioner. The revenue generated by the tram is a very small percentage of the overall revenue

generated by concessioner activities in the park. Although the NPS would no longer collect franchise

fees generated by the commercial tram, these fees represent a small fraction of the park’s overall

operating budget.

Impact Significance. Local, long­term, minor, negligible adverse impact with respect to

maintenance of facilities and septic systems, and long term, moderate adverse impact with respect to

the increased cost of shuttle operations.

Conclusion. Consolidation of infrastructure and improvements to facilities and utilities would result

in a negligible impact on park operations and facilities staff over the long term by reducing timely

and costly maintenance repairs. Elimination of the tram service would result in a local adverse

impact on the existing concessioner, although the revenue generated by the tram is a very small

percentage of the overall revenue generated by concessioner activities in the park. Additional longterm costs would be incurred from the expansion of the shuttle service and infrastructure that must

be maintained.

Cumulative Impacts. The impact of past, present, and reasonably foreseeable projects affecting

park operations would be the same as Alternative 1 (No Action)—a long­term minor beneficial

impact on park operations in the Mariposa Grove area. Under Alternative 2, elimination of the tram

service would result in a local adverse impact on concessioner revenues. This loss would constitute a

very small percentage of the overall revenue generated by concessioner income in the park. The

impacts of Alternative 2 on park operations would generally be local, long­term, and moderate,

adverse from expansion of the shuttle service and infrastructure that must be maintained. The

cumulative effect of past, present, and future actions, in conjunction with the long­term minor

beneficial impacts of Alternative 2, would be long­term, moderate, and adverse.

Final Environmental Impact Statement 3­188 October 2013

Chapter 3: Affected Environment and

Environmental Consequences
   

               

   

         

          

                 

                           

                           

                                 

                         

                             

                                   

                                 

                      

     

                   

               

   

               

                         

                                 

                           

                             

                             

                           

                         

                               

                               

   

                             

                             

             

         

                             

                               

                         

           

                   

                           

                               

                             

                             

                                   

                             

                       

                             

                       

                         

                     

Sociocultural Resources: Park Operations

Restoration of the Mariposa Grove of Giant Sequoias

Alternative 3: Grizzly Giant Hub

Construction­related Impacts. Alternative 3 would remove the commercial tram operation and

consolidate the facilities and infrastructure at Grizzly Giant, but outside of giant sequoia habitat.

Construction­related impacts would be similar to Alternative 2 except that Alternative 3 proposes to

construct a new bypass road, two new bridges, and a new parking lot near Grizzly Giant. The

increase in project components and associated construction would result in higher initial short­term

impacts on operating costs compared to Alternative 2. Increased demands would be placed on park

staff due to a larger area of construction, a longer time period for construction, and the potential for

more traffic delays. The park would need to take additional measures to notify visitors of the status

of the parking areas, bypass road, bridges, and potential traffic delays.

Impact Significance. Local, short­term, minor, adverse impact.

Restoration­related Impacts. Restoration of the Grove would not interfere with or impact park

operations. Existing operations and activities would remain essentially unchanged.

Impact Significance. Local, short­term, negligible impact.

Operation­related Impacts. Consolidating the infrastructure and facilities at Grizzly Giant,

upgrading existing facilities and utilities, simplifying traffic flow, and removing the commercial tram

and shuttle operations would reduce the demand on park facilities staff over the long term and on

the overall park operations and maintenance costs compared to the No Action Alternative. Traffic

congestion related to the occasional closure of the Mariposa Grove Road during periods of heavy

visitation would occur less frequently. This would reduce demands on park facilities staff to provide

traffic control measures. Alternative 3 would eliminate the park’s transit costs related to operating

the shuttle between Wawona, the South Entrance and the lower Grove area. Although the park

would no longer collect franchise fees generated by the commercial tram, these fees represent a small

fraction of the total revenue generated by concessioner services in the park and the park’s overall

operating budget.

Elimination of the tram service would result in a local adverse impact by the existing concessioner,

although the revenue generated by the tram is a very small percentage of the overall revenue

generated by concessioner activities in the park.

Impact Significance. Local, long­term, major, beneficial impact.

Conclusion. The construction of a new bypass road, two bridges, and a new parking lot would result

in an initial short­term increase in park operating costs. However, in the long term, Alternative 3

would improve and simplify operations in the Grove and reduce park operating and maintenance

costs compared to the No Action Alternative.

Cumulative Impacts. The impact of past, present, and reasonably foreseeable projects affecting

park operations would be the same as Alternative 1 (No Action)—a long­term minor beneficial

impact on park operations in the Mariposa Grove area. Under Alternative 3, elimination of the tram

service would result in a local adverse local impact on concessioner revenues. This loss would

constitute a very small percentage of the overall revenue generated by concessioner income in the

park. Construction of a new bypass road, two bridges, and a new parking lot would result in an initial

short­term increase in park operating costs. In the long term, Alternative 3 would improve and

simplify operations in the Grove and reduce the cost of maintenance on deteriorating infrastructure.

The impacts of Alternative 3 on park operations would generally be local, long­term, and minor

beneficial from consolidation of infrastructure and improvements to facilities and utilities. The

cumulative effect of past, present, and future actions, in conjunction with the long­term minor

beneficial impacts of Alternative 3, would be long­term, moderate, and beneficial.

Final Environmental Impact Statement 3­189 October 2013

Chapter 3: Affected Environment and

Environmental Consequences
   

               

   

         

                    

             

                         

                           

                           

                              

     

                   

               

   

                   

                           

                             

                               

                           

                      

                                   

                           

                           

                           

                         

                             

                

         

                     

                                 

                             

             

                   

                           

                               

                           

                           

                       

     

     

                             

                           

Sociocultural Resources: Park Operations

Restoration of the Mariposa Grove of Giant Sequoias

Alternative 4: South Entrance Hub with Modified Commercial Tram Access

Construction­related Impacts. Construction­related impacts under Alternative 4 would result

from the consolidation of most infrastructure and facilities to the South Entrance, realignment of the

commercial tram access road, and construction of new restrooms and a leach field (if feasible).

Short­term impacts would be minor and similar to Alternative 2, except that the road realignment

may require additional park facilities staff and resources to monitor traffic conditions in local areas.

Impact Significance. Local, short­term, minor, adverse impact.

Restoration­related Impacts. Restoration of the Grove would not interfere with or impact park

operations. Existing operations and activities would remain essentially unchanged.

Impact Significance. Local, short­term, negligible impact.

Operation­related Impacts. The facilities and infrastructure would be removed from the lower

Grove area and consolidated at the South Entrance to improve access and serviceability. The existing

ranger station at the South Entrance and existing restroom access would be rehabilitated, a new

comfort station built, the existing water supply system repaired, and a new septic system would be

installed. The addition of new facilities and infrastructure and more complex utility systems would

off­set the savings from upgrading facilities that currently require frequent maintenance.

The NPS would need to increase the bus hours of the Mariposa Grove shuttle by about 35 percent

under Alternative 4, with a proportional increase in transit costs. Although shuttle service would be

reduced between Wawona and lower Grove area, additional service would be provided between the

South Entrance and the lower Grove area and shuttle operations would be expanded into the

shoulder seasons. Although the revenue generated by the commercial tram franchise fees would be

reduced, this represents a small fraction of the total revenue generated by concessioner services in

the park and the park’s overall operating budget.

Impact Significance. Local, long­term, moderate, adverse impact.

Conclusion. Consolidation of infrastructure and improvements to facilities and utilities would result

in a beneficial impact on park operations and facilities staff over the long term by reducing timely

and costly maintenance repairs, but additional costs would be incurred from the expansion of the

shuttle service and infrastructure that must be maintained.

Cumulative Impacts. The impact of past, present, and reasonably foreseeable projects affecting

park operations would be the same as Alternative 1 (No Action)—a long­term minor beneficial

impact on park operations in the Mariposa Grove area. The impacts of Alternative 4 on park

operations would generally be local, long­term, moderate and adverse from expansion of the shuttle

service, facilities and utilities. The cumulative effect of past, present, and future actions, in

conjunction with the long­term minor beneficial impacts of Alternative 4, would be long­term,

moderate, and adverse.

ENERGY USE AND SUSTAINABILITY

Affected Environment

One of the management objectives for park operations, as outlined in previous planning efforts and

Executive Order 13123, is to install facilities and utility systems that conserve energy. Design

Final Environmental Impact Statement 3­190 October 2013

Chapter 3: Affected Environment and

Environmental Consequences
Sociocultural Resources: Energy Use and Sustainability 

Restoration of the Mariposa Grove of Giant Sequoias 

Final Environmental Impact Statement 3-191 October 2013 

Chapter 3: Affected Environment and 

Environmental Consequences 

techniques and application of new technology to reduce energy and water consumption should be 

incorporated in the design of new facilities or replacement of existing facilities. 

In April 1999, the U.S. Department of the Interior entered into a formal Memorandum of 

Understanding with the U.S. Department of Energy to promote the use of energy-efficient and 

renewable energy technologies and practices in national parks, and to educate the visiting public 

about these efforts. This partnership officially inaugurated the program titled “Green Energy Parks: 

Making the National Parks a Showcase for a Sustainable Energy Future.” This initiative would help 

to fulfill provisions of the Energy Policy Act of 1992, which directs the use of energy-efficient 

building designs and equipment and the use of alternative motor fuels where practicable. The Energy 

Policy Act of 2005 incorporates previous Energy Policy Acts and directs the federal government to 

increase its renewable energy use, with a goal of using 3 percent, 5 percent, and 7.5 percent of total 

energy consumption in incremental years through 2013. 

NPS Management Policies 2006 includes a section (Section 9.1.1.6) on sustainable energy design in 

the operation of park facilities. Section 9.1.1.6 states that any facility development must include 

improvements in energy efficiency and reduction in greenhouse gas emissions, and that such 

efficiency should be achieved using solar thermal and photovoltaic application, as well as 

appropriate insulations, energy-efficient lighting and appliances, and renewable energy technologies. 

Furthermore, this section states that energy-efficient construction projects should be used as an 

educational opportunity, and that those built primarily for visitors must incorporate Leadership in 

Energy and Environmental Design® (LEED®) standards to achieve a silver rating (NPS 2006). 

NPS Management Policies 2006 also includes a section (Section 9.1.7) on energy management in the 

operation of park facilities. Section 9.1.7 states that the NPS shall conduct its activities in ways that 

use energy wisely and economically, and that encourages the implementation of alternative 

transportation programs and the use of bio-based and alternative fuels. It also calls for the use of 

renewable sources of energy and new developments in energy-efficiency technology, including 

products from the recycling of materials and waste, where appropriate and cost-effective over the 

life cycle of a facility. Lastly, the management policies call for the interpretation of resource 

protection benefits resulting from the efficient use of energy, and education of park personnel and 

visitors to encourage use of sustainable practices in conserving energy (NPS 2006). These policies are 

derived from the laws that have been enacted to establish and guide the administration of the 

national park system, including 

• Executive Order 13423, Strengthening Federal Environmental, Energy, and Transportation 

Management 

• Executive Order 13123, Greening the Government through Efficient Energy Management, 

which calls on federal agencies to take the lead in implementing energy conservation, 

maximizing the use of renewable resources, and reducing greenhouse gas emissions; and 

• Executive Order 13514: Federal Leadership in Environmental, Energy, and Economic 

Performance, signed in October 2009, which required federal agencies to set a 2020 

greenhouse gas emissions reduction target; increase energy efficiency; reduce fleet petroleum 

consumption; conserve water; reduce waste; support sustainable communities; and leverage 

federal purchasing power to promote environmentally responsible products and 

technologies. 
Sociocultural Resources: Energy Use and Sustainability 

Restoration of the Mariposa Grove of Giant Sequoias 

Final Environmental Impact Statement 3-192 October 2013 

Chapter 3: Affected Environment and 

Environmental Consequences 

Sustainable Design 

President Obama’s Executive Order 13514 provides a unique 

opportunity for federal agencies and facilities to improve sustainabilit

across their operations. The executive order, in addition to its call for 

agencies to implement sustainable practices when constructing and 

operating high-performance Federal buildings, and establishes goals 

for the conservation of water resources at federal facilities, including 

potable, industrial, landscaping, and agricultural water. The executive 

order also calls for pollution prevention through a variety of landscap

management practices (CEQ 2012). 

To help achieve these policy goals, on October 31, 2011 CEQ issued 

Guidance for Federal Agencies on Sustainable Practices for Designed 

Landscapes, which describes strategies to achieve sustainable Federal 

landscape practices. This guidance is to be used by federal agencies for

landscape practices when constructing new, or rehabilitating existing, 

owned or leased facilities, or when landscaping improvements are 

otherwise planned (CEQ 2012). This guidance is based in part on the

Sustainable Sites Initiative. 

y

Figure 3-37 – Solar-powered Sign 

at South Entrance 

e

The Sustainable Sites Initiative (SITES) is an interdisciplinary effort by the American Society of 

Landscape Architects and partners to create voluntary national guidelines and performance 

benchmarks for sustainable land design, construction, and maintenance practices. The U.S. Green 

Building Council, a stakeholder in the initiative, anticipates incorporating these guidelines and 

performance benchmarks into future iterations of the LEED® Green Building Rating System. SITES 

is not intended to be a restoration tool; it is most appropriate as a tool to guide the development of 

designed landscapes. However portions of the project that would be designed, such as parking areas, 

shuttle infrastructure, and other facilities/utilities, could use SITES guidelines to provide the most 

sustainable strategies and practices. As stated in the SITES guidelines, “agencies should strive to 

balance natural resource management priorities with development needs (energy, security, 

infrastructure) while considering cultural, recreational, and environmental resources inherent in the 

landscape. These guidelines are intended to enhance, not inhibit, planning, operations and 

maintenance” (SITES 2012). 

Mariposa Grove Energy Use 

Park facilities and infrastructure within the Grove include comfort stations, small office and storage 

area, the Mariposa Museum, concession gift/snack shop, commercial tram ticket booth structure, 

two water tanks, restroom facilities, paved road, and a paved shuttle bus parking and commercial 

tram staging area. Other amenities include sitting areas, wayside exhibits, trailheads, drinking 

fountain, and trash containers. The NPS Division of Facilities Management performs preventive and 

corrective maintenance on utility infrastructure throughout Mariposa, which includes the water 

supply system, wastewater disposal infrastructure, power, and communications. Electricity at the gift 

shop is supplied by a portable diesel generator and communications equipment at Wawona Point is 

supplied by propane and solar power. 

The concessioner at Mariposa Grove is one of the first such companies in the United States – and the 

first operating in a national park – to be registered to the ISO 14001 environmental management 

standard (Eaton 2012). The use of tractors with clean-diesel engines in Mariposa Grove has reduced 

vehicle emissions (Eaton 2012). The shuttle buses that transport visitors from Wawona and the South 

Entrance to the Mariposa Grove are also alternatively fueled. 
         

               

   

         

                     

                         

                   

                         

                 

       

                         

                           

                         

                             

                         

        

                   

                           

                     

      

                               

                       

                           

                          

    

            

             

           

    

              

              

                    

       

           

                          

                         

  

                         

  

Sociocultural Resources: Energy Use and Sustainability

Restoration of the Mariposa Grove of Giant Sequoias

Energy consumption at the Mariposa Grove occurs largely from May through October. Energy

sources at the Mariposa Grove include electricity (from an onsite, diesel­fueled generator), propane,

and diesel fuel. The communications equipment at Wawona Point is supplemented with propane

during the winter months when meteorological conditions prohibit sole reliance on solar power.

Waste recycling occurs at both the Grove and at the South Entrance.

South Entrance Energy Use

Park facilities and infrastructure at the Yosemite National Park South Entrance area include a singlestory ranger building, garage, entrance office, kiosk, parking lot, paved road, comfort stations, shuttle

stop, and entrance comfort station. Electricity for the South Entrance comfort station and ranger

building is supplied by Pacific Gas and Electric Company via above­ and below­ground power lines.

The ranger building also contains a generator, satellite dish, propane tanks, hazardous materials

storage, and electrical transformer.

The South Entrance and ranger residence operate year­round. Energy consumption at the South 

Entrance includes electricity (ranging from 996 kilowatt hours per month in the summer up to

3,800 kilowatt hours per month in the winter), propane, and diesel fuel.

Environmental Consequences

Intensity Level Definitions

The analysis of energy was based on a qualitative comparison of energy use for the operation,

construction, and maintenance (including repairs) of each alternative. The evaluation is based on

available data and forecasts. For purposes of this analysis, implementation of an alternative is

assumed to have an impact on energy if it results in the following:

Adverse impact:

Increased overall per capita energy consumption

Increased reliance on natural gas and oil

Continued use of inefficient building design

Beneficial impact:

Decrease in overall per capita energy consumption

Decrease reliance on natural gas and oil

Increase use of renewable energy (e.g., photovoltaic cells, wind, geothermal)

Energy­efficient design for new infrastructure

Incorporation of energy­efficient features into existing infrastructure

Negligible – Energy use would not be affected, or effects would not be measurable.

Minor – Effects on energy use, such as increase/decrease in overall consumption, would be

measurable.

Moderate – Effects on energy use, such as increase/decrease in overall consumption, would be

apparent.

Final Environmental Impact Statement 3­193 October 2013

Chapter 3: Affected Environment and

Environmental Consequences
         

               

   

         

                           

        

                   

                         

                       

                       

                       

                           

                         

                           

                                       

                         

                         

                     

       

                       

                     

                   

                   

                             

                       

                               

                               

                         

                     

                           

         

              

                             

                         

                     

                       

                     

                       

                 

                             

                         

                           

                       

                   

                     

Sociocultural Resources: Energy Use and Sustainability

Restoration of the Mariposa Grove of Giant Sequoias

Major – Effects on energy use, such as increase/decrease in overall consumption, would be readily

apparent.

Alternative 1: No Action

Under Alternative 1 current infrastructure, concessioner services and maintenance, and park

management would remain as is. No rehabilitation and restoration actions, such as improvement of

hydrologic flow and universal access, project­specific prescribed fire and hazardous fuel reduction

treatments, soil decompaction, and improvement of visitor orientation and interpretation, would be

implemented.

Operation­related Impacts. Consumption of non­renewable energy (propane and diesel fuel) at the

lower Grove gift shop and commercial tram would continue. The current dispersed transit and

access patterns among the Mariposa Grove, the South Entrance, and Wawona result in extraneous

vehicular mileage, particularly for those visitors who are turned away from the Mariposa Grove

when parking is full and who then board a shuttle bus and drive all back to the Mariposa Grove from

Wawona. This dispersal also adversely impacts maintenance and service expenditures. Long lines at

the South Entrance kiosks and visitor disorientation result in consistent engine idling. There are no

planned improvements to building design in terms of energy and water efficiency.

Impact Significance. Local, long­term, moderate, adverse.

Conclusion. Under Alternative 1 there would be no concerted effort to decrease energy

consumption through sustainable design and no impetus to use alternative energy sources, resulting

in local, long­term, moderate adverse impacts on energy use and sustainability.

Cumulative Impacts. This cumulative impact analysis considers the present and reasonably

foreseeable future actions related to energy use and sustainability in the Mariposa Grove area, in

combination with the impacts of Alternative 1. The potential impacts from the operation,

construction, and maintenance of most of the present plans and projects listed in Appendix B would

result in a small increase in overall per capita energy consumption. Overall, these actions constitute a

short­term negligible adverse impact on energy use and sustainability in the area. Under

Alternative 1, there would be no actions taken to decrease energy consumption through sustainable

design and no use of alternative energy sources, resulting in local, long­term, moderate adverse

impacts on energy use and sustainability.

Alternative 2: South Entrance Hub (Preferred Alternative)

Alternative 2 would remove the commercial tram operation and reduce the amount of lower Grove

parking while expanding and relocating primary visitor parking to the South Entrance, making the

South Entrance the departure point for visitors accessing the Grove. Numerous other rehabilitation

and restoration actions, such as improvement of hydrologic flow and universal access, projectspecific prescribed fire and hazardous fuel reduction treatments, soil decompaction, and

improvement of visitor orientation and interpretation, would be components of this alternative.

Construction­related Impacts. Construction energy expenditures for the development of the new

parking lot and visitor contact area at the South Entrance and the Three Sentinels Bridge under

Alternative 2 would include both direct and indirect uses of energy. Combustion of petroleum

products needed to operate construction equipment would be included in the direct energy use

during the construction period. The energy consumed through mining and extraction of raw

materials, manufacturing, and transportation to produce the construction materials is considered

indirect energy use. Indirect energy typically represents about three­quarters of total construction

Final Environmental Impact Statement 3­194 October 2013

Chapter 3: Affected Environment and

Environmental Consequences
         

               

   

         

                         

                           

                  

                     

         

                               

                       

                    

                               

                               

                           

                                 

                           

                                   

                       

                       

                       

                           

                           

           

     

                 

                                   

                         

                                 

                   

     

               

                                 

                           

                     

                         

                           

                           

                               

                             

                             

                       

                                 

                           

                         

                   

               

     

Sociocultural Resources: Energy Use and Sustainability

Restoration of the Mariposa Grove of Giant Sequoias

energy, while direct energy represents about one­quarter of the total construction energy (Hannon

et al. 1978). Though construction energy would be consumed only during the construction period, it

would represent the irreversible consumption of finite natural energy resources.

Construction activities under Alternative 2 would consume fuel and electricity, along with indirect

energy for materials used in constructing development components. Construction equipment,

including haul trucks and vehicles onsite, is expected to consume a majority of the energy resources.

Electricity would be used by construction equipment, such as welding machines and power tools.

Energy consumed by construction power equipment would be relatively minimal.

The amount of energy consumed each day would vary depending on a number of factors, such as the

number and types of equipment in operation on a given day, usage rates, the number of construction

workers needed, the number of haul trips, and trip length. Construction energy consumption would

occur for the duration of the construction period and therefore would not be an ongoing drain on

finite natural resources. Construction energy consumption would primarily be in the form of fuel,

would not have a significant effect on the energy resources of the park, and would not require new

infrastructure. The design plan under Alternative 2 includes measures that would reduce

construction energy expenditure through the use of recycled materials. BMPs for air quality and

noise would help reduce fuel consumption by construction equipment (e.g., ensuring all

construction equipment is properly tuned and maintained, turning off equipment when not in use).

Furthermore, materials removed as part of the demolition of existing campus facilities would be

sorted and salvaged for reuse or recycling.

Impact Significance. Local, short­term, moderate, and adverse.

Restoration­related Impacts. Restoration energy consumption would occur as pavement is ripped

up along the Mariposa Grove Road and in the lower Grove parking lot and during culvert work and

installation. However, this would not be an ongoing drain on finite natural resources. Restoration

energy consumption would primarily be in the form of fuel, would not have a significant effect on the

energy resources of the park, and would not require new infrastructure.

Impact Significance. Local, short­term, minor, and adverse.

Operation­related Impacts. The consumption of non­renewable energy (propane and diesel fuel)

and electricity in the lower Grove area would be eliminated. Under this alternative there is an option

to be “off the grid.” Consolidation of Mariposa Grove facilities and infrastructure at the South 

Entrance would result in improved access and serviceability, reducing expenditures. The South 

Entrance intersection congestion would be alleviated by installation of a roundabout if needed, and

current plans to move the entrance kiosks southward away from the Wawona Road/Mariposa Grove

Road intersection. This improvement in traffic flow would result in fewer or shorter back­ups and

less idling by vehicles. Vehicle miles traveled would also be reduced as fewer visitors would be

driving to Wawona and “backtracking” to the Mariposa Grove on the park shuttle bus system.

Under Alternative 2, a new visitor contact area at the South Entrance would be designed in

accordance with the NPS Guiding Principles of Sustainable Design (1993). These principles include

the orientation of buildings to maximize sun exposure for heat gain and to minimize the effects of

prevailing winds, design that incorporates the use of natural ventilation, entry vestibules to reduce

heat loss, energy­efficient lighting, and the installation of energy­ and water­efficient features and

utilities. Other “green” elements to be incorporated include energy­efficient construction design,

sustainability and “green” technology, lighting, site drainage, water conservation, wastewater

management, and energy conservation.

Final Environmental Impact Statement 3­195 October 2013

Chapter 3: Affected Environment and

Environmental Consequences
         

               

   

         

     

                       

                     

             

                   

                             

                             

                       

                         

                         

                           

                   

          

                             

                                   

                               

                               

                       

                       

                     

                       

   

                 

                             

                     

                             

                   

                       

                       

                       

                       

            

                     

         

                               

                       

                    

                               

                               

                           

                                 

                           

                                   

                       

                       

Sociocultural Resources: Energy Use and Sustainability

Restoration of the Mariposa Grove of Giant Sequoias

Impact Significance. Local, long­term, moderate, beneficial.

Conclusion. Under Alternative 2 there would be a concerted effort to decrease energy consumption

through sustainable design while using alternative energy sources, resulting in local, long­term,

moderate beneficial impacts on energy use and sustainability.

Cumulative Impacts. The impact of past, present and reasonably foreseeable projects affecting

energy use and sustainability would be the same as Alternative 1 (No Action)—a long­term negligible

adverse impact on energy use and sustainability in the Mariposa Grove area. Under Alternative 2,

there would be a concerted effort to decrease energy consumption through sustainable design while

using alternative energy sources, resulting in local, long­term, moderate beneficial impacts on energy

use and sustainability. Present and past plans and projects, in conjunction with the moderate

beneficial impacts of Alternative 2, would result in an overall long­term moderate beneficial impact

on energy use and sustainability in the Mariposa Grove area.

Alternative 3: Grizzly Giant Hub

Alternative 3 would remove the commercial tram operation and build a new bypass road, including

two new bridges, and a new larger parking lot near the Grizzly Giant, but outside of giant sequoia

habitat. This alternative would make the Grizzly Giant the primary departure point for visitors to the

Grove. The current South Entrance parking lot would remain as is and the lower Grove parking lot

would be removed; a small lot of ABAAS­compliant parking spaces would be constructed.

Numerous other rehabilitation and restoration actions, such as improvement of hydrologic flow and

universal access, project­specific prescribed fire and hazardous fuel reduction treatments, soil

decompaction, and improvement of visitor orientation and interpretation, would be components of

this alternative.

Construction­related Impacts. Construction energy expenditures for the new access road, two

bridges, and parking lot near the Grizzly Giant under Alternative 3 would include both direct and

indirect uses of energy. Combustion of petroleum products needed to operate construction

equipment would be included in the direct energy use during the construction period. The energy

consumed through mining and extraction of raw materials, manufacturing, and transportation to

produce the construction materials is considered indirect energy use. Indirect energy typically

represents about three­quarters of total construction energy, while direct energy represents about

one­quarter of the total construction energy (Hannon et al. 1978). Though construction energy

would be consumed only during the construction period, it would represent the irreversible

consumption of finite natural energy resources.

Construction activities under Alternative 3 would consume fuel and electricity, along with indirect

energy for materials used in constructing development components. Construction equipment,

including haul trucks and vehicles onsite, is expected to consume a majority of the energy resources.

Electricity would be used by construction equipment, such as welding machines and power tools.

Energy consumed by construction power equipment would be relatively minimal.

The amount of energy consumed each day would vary depending on a number of factors, such as the

number and types of equipment in operation on a given day, usage rates, the number of construction

workers needed, the number of haul trips, and trip length. Construction energy consumption would

occur for the duration of the construction period and therefore would not be an ongoing drain on

finite natural resources. Construction energy consumption would primarily be in the form of fuel,

would not have a significant effect on the energy resources of the park, and would not require new

infrastructure. The design plan under Alternative 2 includes measures that would reduce

construction energy expenditure through the use of recycled materials. BMPs for air quality and

Final Environmental Impact Statement 3­196 October 2013

Chapter 3: Affected Environment and

Environmental Consequences
         

               

   

         

                       

                           

                           

           

     

                 

                                   

                         

                                 

                   

     

                   

                             

                     

                         

                         

                               

                             

                           

                         

                           

                         

              

                                   

                       

                             

                             

                         

                     

                   

         

     

                       

                       

                             

   

                     

                             

                             

                       

                         

                         

Sociocultural Resources: Energy Use and Sustainability

Restoration of the Mariposa Grove of Giant Sequoias

noise would help reduce fuel consumption by construction equipment (e.g., ensuring all

construction equipment is properly tuned and maintained, turning off equipment when not in use).

Furthermore, materials removed as part of the demolition of existing campus facilities would be

sorted and salvaged for reuse or recycling.

Impact Significance. Local, short­term, moderate, and adverse.

Restoration­related Impacts. Restoration energy consumption would occur as pavement is ripped

up along the Mariposa Grove Road and in the lower Grove parking lot and during culvert work and

installation. However, this would not be an ongoing drain on finite natural resources. Restoration

energy consumption would primarily be in the form of fuel, would not have a significant effect on the

energy resources of the park, and would not require new infrastructure.

Impact Significance. Local, short­term, moderate, and adverse.

Operation­related Impacts. This alternative would include a reduction in the use of non­renewable

energy (propane and diesel fuel) as the proposed Grizzly Giant visitor contact area would be

completely “off the grid.” All development would showcase sustainable design and establish 

precedence. No shuttle infrastructure would be required. The simplified access pattern to the

Mariposa Grove directly from the South Entrance would likely reduce vehicular mileage due to

visitor confusion and back­tracking from Wawona, but this would likely be offset by the lack of

alternative transit to the Grove and additional vehicle miles traveled to the Grizzly Giant Hub.

Consolidation of Mariposa Grove facilities and infrastructure at the Grizzly Giant Hub would clarify

access and improve serviceability. Most winter access would be from the South Entrance and

plowing of the Mariposa Grove Road would be minimal. Seasonal shuttle operations would be

extended. Service access to Wawona Point and the upper Grove comfort station and repurposed

museum would be via hardened narrow road.

Under Alternative 3, a new visitor contact area at the Grizzly Giant would be “off the grid” and

designed in accordance with the NPS Guiding Principles of Sustainable Design (1993). These

principles include the orientation of buildings to maximize sun exposure for heat gain and to

minimize the effects of prevailing winds, design that incorporates the use of natural ventilation, entry

vestibules to reduce heat loss, energy­efficient lighting, and the installation of energy­ and waterefficient features and utilities. Other “green” elements to be incorporated include energy­efficient

construction design, sustainability and “green” technology, lighting, site drainage, water

conservation, wastewater management, and energy conservation.

Impact Significance. Local, short­term, moderate, and beneficial.

Conclusion. Under Alternative 3 there would be a concerted effort to decrease energy consumption

through sustainable design and to use alternative energy sources, resulting in local, long­term,

moderate beneficial impacts on energy use and sustainability but slightly less than that described for

Alternative 2.

Cumulative Impacts. The impact of past, present and reasonably foreseeable projects affecting

energy use and sustainability would be the same as Alternative 1 (No Action)—a long­term negligible

adverse impact on energy use and sustainability in the Mariposa Grove area. Under Alternative 3,

there would be a concerted effort to decrease energy consumption through sustainable design while

using alternative energy sources, resulting in local, long­term, moderate beneficial impacts on energy

use and sustainability. Present and past plans and projects, in conjunction with the moderate

Final Environmental Impact Statement 3­197 October 2013

Chapter 3: Affected Environment and

Environmental Consequences
         

               

   

         

                           

                   

                   

                             

                         

                           

                       

                   

            

                 

                           

                         

                           

                     

                       

                       

                       

                           

            

                     

         

                               

                       

                    

                               

                               

                           

                                 

                           

                                   

                       

                       

                       

                           

                           

           

       

                 

                                 

                           

                                       

     

     

Sociocultural Resources: Energy Use and Sustainability

Restoration of the Mariposa Grove of Giant Sequoias

beneficial impacts of Alternative 3, would result in an overall long­term moderate beneficial impact

on energy use and sustainability in the Mariposa Grove area.

Alternative 4: South Entrance Hub with Modified Commercial Tram Service

Alternative 4 would maintain the commercial tram but with a limited route and hours of operation

while also relocating the majority of the parking to the South Entrance, making the South Entrance

the primary departure point for visitors to the Grove. Numerous other rehabilitation and restoration

actions, such as improvement of hydrologic flow, project­specific prescribed fire and hazardous fuel

reduction treatments, soil decompaction, and improvement of visitor orientation and interpretation,

would be components of this alternative.

Construction­related Impacts. Construction energy expenditures for the development of the new

parking lot and visitor contact area at the South Entrance under Alternative 4 would include both 

direct and indirect uses of energy. Combustion of petroleum products needed to operate

construction equipment would be included in the direct energy use during the construction period.

The energy consumed through mining and extraction of raw materials, manufacturing, and

transportation to produce the construction materials is considered indirect energy use. Indirect

energy typically represents about three­quarters of total construction energy, while direct energy

represents about one­quarter of the total construction energy (Hannon et al. 1978). Though 

construction energy would be consumed only during the construction period, it would represent the

irreversible consumption of finite natural energy resources.

Construction activities under Alternative 4 would consume fuel and electricity, along with indirect

energy for materials used in constructing development components. Construction equipment,

including haul trucks and vehicles onsite, is expected to consume a majority of the energy resources.

Electricity would be used by construction equipment, such as welding machines and power tools.

Energy consumed by construction power equipment would be relatively minimal.

The amount of energy consumed each day would vary depending on a number of factors, such as the

number and types of equipment in operation on a given day, usage rates, the number of construction

workers needed, the number of haul trips, and trip length. Construction energy consumption would

occur for the duration of the construction period and therefore would not be an ongoing drain on

finite natural resources. Construction energy consumption would primarily be in the form of fuel,

would not have a significant effect on the energy resources of the park, and would not require new

infrastructure. The design plan under Alternative 4 includes measures that would reduce

construction energy expenditure through the use of recycled materials. BMPs for air quality and

noise would help reduce fuel consumption by construction equipment (e.g., ensuring all

construction equipment is properly tuned and maintained, turning off equipment when not in use).

Furthermore, materials removed as part of the demolition of existing campus facilities would be

sorted and salvaged for reuse or recycling.

Impact Significance. Local, short­term, moderate, and adverse.

Restoration­related Impacts. Restoration energy consumption would occur as pavement is ripped

up in the lower Grove parking lot and during culvert work and installation. However, this would not

be an ongoing drain on finite natural resources. Restoration energy consumption would primarily be

in the form of fuel, would not have a significant effect on the energy resources of the park, and would

not require new infrastructure.

Impact Significance. Local, short­term, minor, and adverse.

Final Environmental Impact Statement 3­198 October 2013

Chapter 3: Affected Environment and

Environmental Consequences
         

               

   

         

               

                   

                   

                     

                     

                     

                             

                           

                             

                         

                                   

      

                             

                       

                                 

                           

                         

                   

               

     

       

                       

                         

                             

           

                     

                             

                             

                       

                               

                           

                           

                             

           

Sociocultural Resources: Energy Use and Sustainability

Restoration of the Mariposa Grove of Giant Sequoias

Operation­related Impacts. In­park vehicular mileage for visitors would be reduced through much 

improved transit and access patterns and improved transit communication through the proposed

electronic parking availability system. Consolidation of Mariposa Grove facilities and infrastructure

at the South Entrance would result in improved access and serviceability, reducing expenditures.

The South Entrance congestion would be alleviated by modifying the existing T­intersection moving

the entrance kiosks southward away from the Wawona Road/Mariposa Grove Road intersection.

This improvement in traffic flow would result in fewer or shorter back­ups and less idling by

vehicles. New flush restrooms for lower Grove area would replace existing vault toilets. Most winter

access would be from the South Entrance and plowing of the Mariposa Grove Road would be

minimal Seasonal shuttle operations would be extended. Service access the upper Grove comfort

station and repurposed museum would be via a paved road. Access to Wawona Point would be via a

hardened narrow road.

Under Alternative 4, a new visitor contact area at the South Entrance would be designed in

accordance with the NPS Guiding Principles of Sustainable Design (1993). These principles include

the orientation of buildings to maximize sun exposure for heat gain and to minimize the effects of

prevailing winds, design that incorporates the use of natural ventilation, entry vestibules to reduce

heat loss, energy­efficient lighting, and the installation of energy­ and water­efficient features and

utilities. Other “green” elements to be incorporated include energy­efficient construction design,

sustainability and “green” technology, lighting, site drainage, water conservation, wastewater

management, and energy conservation.

Impact Significance. Local, short­term, minor, and beneficial.

Conclusion. Under Alternative 4 there would be a concerted effort to decrease energy consumption

through sustainable design and to use alternative energy sources; however, these would be partially

offset by the continued use of the commercial tram which would result in local, long­term, minor

beneficial impacts on energy use and sustainability.

Cumulative Impacts. The impact of past, present and reasonably foreseeable projects affecting

energy use and sustainability would be the same as Alternative 1 (No Action)—a long­term negligible

adverse impact on energy use and sustainability in the Mariposa Grove area. Under Alternative 4,

there would be a concerted effort to decrease energy consumption through sustainable design while

using alternative energy sources; however, these would be partially offset by the continued use of the

commercial tram which would result in local, long­term, minor beneficial impacts on energy use and

sustainability. recent and past plans and projects, in conjunction with the minor beneficial impacts of

Alternative 4, would result in an overall long­term minor beneficial impact on energy use and

sustainability in the Mariposa Grove area.

Final Environmental Impact Statement 3­199 October 2013

Chapter 3: Affected Environment and

Environmental Consequences