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CHAPTER 2: ALTERNATIVES
 

INTRODUCTION

This chapter presents the four alternatives (including a preferred alternative) proposed in the

Restoration of the Mariposa Grove of Giant Sequoias/Final Environmental Impact Statement (Mariposa

Grove FEIS). These alternatives represent a range of management approaches, each of which would

achieve the goals of the project, as required by the National Environmental Policy Act (NEPA). Each 

of the action alternatives is a comprehensive proposal to meet the goals of restoring degraded giant

sequoia habitat and the natural processes critical to the long­term health of the Grove, and to

improve the overall experience for visitors (see Chapter 1: Purpose and Need). The No Action

Alternative represents a continuation of current management practices and provides a basis to

compare differences among the alternatives.

This chapter includes the following:

•	 A description of the Choosing by Advantages process which guided alternative development

(pages 2­2 to 2­4)

•	 A description of each alternative (pages 2­5 to 2­30)

•	 Alternatives considered but dismissed from further analysis (pages 2­31 to 2­33)

•	 The environmentally preferred alternative (pages 2­33 to 2­35)

•	 Cost estimates associated with implementing the alternatives (page 2­36)

•	 A summary comparison of the alternatives (Table 2­2)

•	 A summary of potential impact and restoration footprint areas (Table 2­3)

CHANGES BETWEEN THE DRAFT AND FINAL

ENVIRONMENTAL IMPACT STATEMENT (EIS)

The National Park Service (NPS) issued the Restoration of the Mariposa Grove of Giant

Sequoias/Draft Environmental Impact Statement (Draft EIS) to the public in February 2013. In

response to the comments received on the Draft EIS and new technical information, the NPS revised

Alternative 2 (the agency­preferred alternative) and Alternative 4 of the Mariposa Grove Final EIS.

Alternatives 1 and 3 remain the same as in the Draft EIS. The process of comment analysis is

described in Chapter 4 (Consultation, Coordination, and Preparers). Written responses to public

concerns are located in Appendix C, Public Comments and Responses. The following revisions to

the Draft EIS are integrated into the Mariposa Grove Final EIS:

1.	 Reconfigure facilities at the South Entrance hub to accommodate 26 additional parking

spaces (from 269 in the Draft EIS to 295 in the final plan), including flex­spaces to

accommodate oversize vehicles. Rationale for change: The increased capacity of the

parking lot would ensure that the proposed facility accommodates existing levels of

visitation.

2.	 Provide an off­season overflow parking lot along the Mariposa Grove Road near the picnic

area. New analysis showed that the 50­car lot proposed in the Draft EIS would not be

sufficient to accommodate use when the shuttle is not in operation. Rationale for change:

Final Environmental Impact Statement  2­1 October 2013

Chapter 2: Alternatives
               

   

   

                            

                 

                           

                         

           

                           

                     

                                 

                       

                         

                                 

                           

                                     

               

                         

                     

                       

                       

                           

                             

                               

                         

                       

                           

                     

                           

                                 

                             

                               

   

                               

                         

                               

                           

                                     

                     

                           

                       

                             

        

       

          

Alternatives

Restoration of the Mariposa Grove of Giant Sequoias

Parking near the picnic area would provide additional parking in close proximity to the

Mariposa Grove when the shuttle would not be operating.

3.	 Increase the size of the buried water tank at the South Entrance. Rationale for change: The

increased size of the water tank would better accommodate anticipated water needs for

consolidation of visitor services at the South Entrance.

4.	 Explore additional options for the location of the septic system and leach field at the South 

Entrance. Rationale for change: New geotechnical data indicated that soil conditions might

not be conducive for the layout and size of the leach fields identified in the Draft EIS. Final

locations for the septic system and leach fields will be based on continuing geotechnical

investigations and soil surveys. The range of options in the Final EIS includes flush toilets,

vault toilets, options for leach field sites, and an option to install a sewer line from the lower

Grove area to the South Entrance, all within the project area identified in the plan.

In addition to these changes, the Final EIS was edited to improve clarity and add detail in response to

public comments, primarily in Chapters 2 and 3.

ALTERNATIVES

The Mariposa Grove FEIS describes and analyzes four alternatives: a No Action alternative that

represents the continuation of existing conditions and management, and three action alternatives.

All the action alternatives propose ecological restoration activities, selected utility repairs or

upgrades, and rehabilitation of historic features at Wawona Point, although the alternatives differ in

the buildings and infrastructure proposed for removal and relocation. Initial design concepts for the

restoration of the Grove were formulated during three design charettes that were held in January,

March, and May of 2012. NPS and regional staff representing various technical disciplines, as well as

the contracted designer and compliance staff, participated in the charettes. Resource issues and

concerns were identified based on research and baseline data documenting the existing conditions

within the Grove. Park staff, assisted by the designers, identified numerous potential solutions. These

concepts were iteratively assessed and improved, resulting in five preliminary alternatives. A

Choosing by Advantages (CBA) workshop, including a value analysis component, was held in June

2012 and resulted in the selection of the alternatives for detailed analysis in this EIS. These sessions

were augmented by a separate value analysis for design alternatives to reconfigure the intersection of

Wawona Road (State Route 41) and the Mariposa Grove Road that was held in July 2012.

CHOOSING BY ADVANTAGES/VALUE ANALYSIS WORKSHOPS

Three design charettes were conducted in January, March, and May of 2012 with the project team,

which included Yosemite National Park staff and management, NPS Pacific West Region staff, and

contractors. A wide variety of concepts for restoring the ecology of the Mariposa Grove of Giant

Sequoias and improving the visitor experience were considered. A CBA workshop was held in

El Portal on June 5­6, 2012. The CBA process is a ranking process that is based on the relative

advantages and costs of each alternative in accomplishing servicewide goals and objectives. Through

the CBA process, alternatives for the Mariposa Grove restoration effort were evaluated to determine

which should be carried through the EIS­level of analysis. The alternatives considered during the

CBA process included Alternative A (No Action) and five action alternatives that emerged from the

design charettes, as follows:

•	 Alternative B: South Entrance Hub

•	 Alternative C: Grizzly Giant Hub

Final Environmental Impact Statement  2­2 October 2013

Chapter 2: Alternatives
               

   

   

          

                   

             

                    

                             

                           

                         

                               

                           

                             

                                 

                               

                       

         

                                 

                     

                               

                               

                

                               

                           

                               

                       

                           

                             

                         

                     

            

Alternatives

Restoration of the Mariposa Grove of Giant Sequoias

•	 Alternative D: Lower Grove Hub

•	 Alternative E: South Entrance Hub II (included removal of commercial tram,
 

communications tower, and road within the Grove)
 

•	 Alternative F: South Entrance Hub III (included limited commercial tram access)

Following the CBA workshop, the NPS recommended refinement of Alternatives B, E, and F, in

addition to the no­action Alternative A, for analysis in the EIS. During the park’s reconsideration

phase, these three action alternatives were further developed and refined. With the public comment

received during an open house in June 2012 and further staff analysis and discussion, the NPS

concluded that Alternative E, without removal of the commercial tram road too closely resembled

Alternative B, and that Alternative C provided different approaches to meeting the purpose and need

and should be fully assessed in the Draft EIS. Alternative D did not adequately meet the project

purpose and need. Alternatives B, C, and F are evaluated in this EIS as Alternatives 2 (South Entrance

Hub), 3 (Grizzly Giant Hub), and 4 (South Entrance Hub with Modified Commercial Tram Service),

respectively.

Figure 2­1 – Choosing by Advantages Workshop

A separate value analysis workshop was held on July 19, 2012, to identify and rank possible designs

for an improved Wawona Road/Mariposa Grove Road intersection at South Entrance. The

workshop objective was to ensure consideration of a range of proposals, and to ensure that the

project satisfied the park’s needs with the lowest impact on resources in the context of criteria that

relate directly to NPS service­wide goals and objectives.

The highest ranked option to address issues at the Wawona and Grove roads intersection was the

planned kiosk expansion, as represented in the No Action alternative. If vehicular back­ups continue

at the intersection after the kiosk improvements, and extend to the kiosks over a sustained period,

the park could implement the roundabout option, which was the second highest ranked intersection

option. An optimized roundabout is proposed as an option in Alternative 2: South Entrance Hub.

This option has several advantages over the current T­intersection design in terms of traffic capacity

and safety but is associated with additional costs. A modified T­intersection is incorporated into

Alternative 4: South Entrance Hub with Modified Commercial Tram Service. This option had the

lowest score and lowest benefit­to­cost ratio.

Final Environmental Impact Statement  2­3 October 2013

Chapter 2: Alternatives
       

               

   

   

       

Alternative 1: No Action

Restoration of the Mariposa Grove of Giant Sequoias

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Final Environmental Impact Statement  2­4 October 2013

Chapter 2: Alternatives
       

               

   

   

   

                               

                               

                           

                         

                   

                     

               

                        

                               

                       

                         

                               

                         

                           

                               

                               

                           

                               

                           

                           

                 

                             

                                 

                             

                               

                                   

                               

                         

                         

               

                               

                                   

                       

                                   

                               

                               

                            

                           

                        

Alternative 1: No Action

Restoration of the Mariposa Grove of Giant Sequoias

ALTERNATIVE 1: NO ACTION

Under Alternative 1, No Action, the lower Mariposa Grove area would continue to serve as the

primary arrival and departure point and contact area for visitors to the Grove. Existing buildings and

infrastructure in the Grove and at South Entrance would remain. These include the Grove parking

lot, the paved commercial tram loop road, tram staging, the concessioner­operated gift shop,

Wawona Point overlook features and communications equipment, comfort stations, the Mariposa

Grove Museum, and utilities infrastructure (figures 2­2 through 2­4). Under this alternative,

compliance with regulatory requirements (e.g., health and safety or historic preservation) or

strategies in current and future adopted plans would be implemented over time.

Individual giant sequoia trees as well as sequoia habitat would continue to be impacted by buildings,

roads, utilities, and other infrastructure that are adversely impacting tree roots and regeneration,

soils, and hydrologic flow. Paved roads, in­sloped trails, and damaged and insufficient culverts

would continue to impede sheet flow and divert water from the Grove, and denuded and compacted

soils would continue to limit water infiltration and giant sequoia seedling germination. Plugged

culverts would be cleaned as part of routine maintenance; however, additional and/or larger culverts

would not be installed. The deteriorating water supply system would continue to leak, and the water

storage tank and chlorination unit would remain along the upper Grove loop road (figure 2­2), and

continue to require maintenance vehicle access. The gift shop, its diesel­powered generator, and the

visitor parking lot would remain in place, and the poorly functioning vault toilets would remain at

the entrance to the Grove. Park and concessioner operations and overall management of Mariposa

Grove would continue as is, including commercial tram staging and operation in and around

sensitive natural resources. Facilities and trails would have limited accessibility.

Currently, there is limited parking at South Entrance (~20 spaces) and the Grove (115 spaces, of

which 2 are designated for accessible use, as shown in figures 2­2 and 2­4). When the Grove parking

lot capacity is reached and the Mariposa Grove Road closes (most commonly during peak season

from Memorial Day to Labor Day), visitors attempting to access the Grove are directed to Wawona

(over 100 spaces during peak use) by staff at South Entrance. At Wawona, visitors can park and take a

free shuttle bus to the Grove. The headways for the park’s shuttle service from Wawona average

about 15 minutes with stops at South Entrance and Mariposa Grove. This process results in

backtracking and considerable visitor frustration; some visitors may decide against visiting the Grove

given the time and effort required to reach that destination.

Under Alternative 1, staff would continue to redirect potential Grove visitors to Wawona to take the

shuttle when parking areas are full. At present, Wawona is a staging area for the Grove when the

Grove and South Entrance parking areas are full. At Wawona, personal vehicles and commercial

buses park along the road and in the parking lot for the market and the Pioneer Yosemite History

Center to catch shuttles for visitors wanting to go to the Grove. Concessioner staff would continue to

provide traffic control at the Mariposa Grove Road gate and the Grove parking lot. While the

separate project to relocate the South Entrance kiosks is in­progress, and is expected to alleviate

some traffic congestion and confusion in the area, Mariposa Grove visitors may continue to

experience occasional backups from the kiosk to the park boundary (figure 2­3).

Final Environmental Impact Statement  2­5 October 2013

Chapter 2: Alternatives
       

               

   

   

  

                         

                           

                               

                       

                           

                                 

                                 

        

       

                                     

                         

            

                           

                                 

                           

                 

              

                         

                             

                         

                       

         

                           

                                   

                         

                           

                               

                         

  

                       

                             

                   

                         

                       

                       

                             

                     

                                       

                 

                             

                               

Alternative 1: No Action

Restoration of the Mariposa Grove of Giant Sequoias

Accessibility

Under the no­action alternative, visitors with limited mobility can experience the giant sequoias and

other remarkable natural and cultural resources in the Mariposa Grove by taking a commercial tram

tour, or by following the tram tours in a placarded vehicle (i.e., a vehicle displaying a state­issued

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

permit). The other universally accessible facilities in the lower Grove area include two parking

spaces and eight vault toilets. In the upper Grove area, the museum is accessible for vehicles parked

in the immediate vicinity. Within the Grove, the existing bus drop­off area, parking, and trails do not

meet current accessibility standards.

ACTIONS COMMON TO ALL ACTION ALTERNATIVES

A set of the proposed actions to address the purpose and need for this effort are common to all

action alternatives (Alternatives 2, 3, and 4). This section describes these common actions to avoid

redundancy in the sections that follow.

Remove Existing Parking from the Lower Grove Area and Restore Habitat – All action

alternatives call for the removal of the existing Grove parking lot and the restoration of giant sequoia

habitat in the lower Grove area. This would entail removing asphalt, decompacting soils, and

revegetating with understory plants through propagules and seeding. The restoration plan for

Mariposa Grove is included as Appendix D.

Improve Orientation and Way Finding – Comments received during public scoping and from park

staff indicated that orientation and way­finding signage at the entrance and within the Grove could

be improved. All action alternatives would include additional signage where needed to provide

clearer orientation, interpretation, and direction to visitors upon arrival at the South Entrance to the

park and at Mariposa Grove.

Rehabilitation of Wawona Point – All action alternatives call for rehabilitation of historic features

at Wawona Point. Wawona Point provides a scenic vista of the western edge of the park and the

South Fork Merced River valley, stretching toward the Sierra Nevada foothills and the Central

Valley beyond. Historic rehabilitation would include repair of rock work, steps, paths and railings,

and removal of remnant asphalt pavement in what was historically a parking area at the summit.

Ecological restoration activities would include revegetation of denuded areas and where pavement is

removed.

Engineered Hydrology and Road Improvements – All action alternatives include the repair or

replacement of drainage culverts and the grading/outsloping of roads and trails within the Grove to

promote unimpeded sheet flow and infiltration of snowmelt and rainwater. The improvements

would reduce channelization and erosion, and would correct flow barriers that currently divert

water both within the Grove and from the Grove watershed entirely. Routine inspection and

maintenance would be required to keep culverts clear of debris and sediment.

Removal of Gift Shop from Lower Grove Area – Under all action alternates, the existing

concessioner­operated gift shop and the associated diesel­powered generator would be removed

from the lower part of the Grove. The gift shop building is an intrusion on the natural setting and the

generator is a source of noise and air emissions.

Repair of Water Supply Pipeline – All action alternatives would include relocation of the water

treatment and storage units in the upper Grove area, and repair or replacement of the associated

Final Environmental Impact Statement  2­6 October 2013

Chapter 2: Alternatives
       

               

   

   

                       

                             

                           

                           

         

                   

                               

                

                         

                               

                           

                               

                     

  

                                 

                             

   

                   

                     

                           

                             

                     

                             

                                   

                         

                             

                                 

  

                     

                         

                   

                   

                       

                           

                             

                  

                   

                           

                           

            

                             

                             

                                   

              

Alternative 1: No Action

Restoration of the Mariposa Grove of Giant Sequoias

leaking water distribution piping. The distribution system conveys spring water from Biledo

Meadow, located east of Mariposa Grove on U.S. Forest Service land, through the upper Grove area,

and to Mariposa Grove and South Entrance facilities. The pipeline is leaking chlorinated water, and

may be affecting local hydrology and vegetation. The NPS would conduct a Wilderness Minimum

Analysis Requirement for all actions within Wilderness.

Structural and Utility Sustainability Improvements – All action alternatives would relocate

facilities and functions that do not contribute to the historic significance of the Grove to areas

outside of sensitive giant sequoia habitat and wetlands.

For relocated facilities, actions would be undertaken in accordance with the National Park Service

Guiding Principles of Sustainable Design (1993) and A Sense of Place – Design Guidelines for Yosemite

National Park (2012). These principles include the orientation of buildings to optimize seasonal solar

exposures and to minimize the effects of prevailing winds, design that incorporates the use of natural

ventilation, energy­efficient lighting, and the installation of energy­ and water­efficient fixtures and

utilities.

Commercial Bus Tours – In the future, the NPS may need to institute a permit reservation system

for commercial tour buses, if demand exceeds the capacity of the septic system or commercial bus

parking spaces.

Grove Vicinity Fire Management – All action alternatives would include continued mechanical

thinning and prescribed fire as prescribed in the Fire Management Plan (NPS 2004a). Though fire

management activities such as these have been occurring within the Grove since the early 1970s,

heavy buildup of surface fuels and dense understories are widespread in forested areas around the

Mariposa Grove. Planned fire management activities under the current Fire Management Plan (NPS

2004a) include mechanical thinning of trees smaller than 20 inches in diameter at breast height

(excluding sequoias and black oaks) and prescribed fire in units to the south, east, and west of the

Grove. Implementation of planned fire management activities south and west of the Grove to the

park’s boundary with the Sierra National Forest would help mitigate the risk of a catastrophic crown

fire reaching the Grove, as these areas are upwind of the Grove (i.e. the prevailing winds are

southwesterly).

Universal Accessibility – Each of the action alternatives would extend opportunities for universal

access and enjoyment of resources within the Mariposa Grove. The action alternatives would

include construction of universally accessible transportation hubs and comfort stations in

accordance with applicable policies and guidance. Each would also include a universally accessible

trail through the lower portion of the Grove, which would greatly enhance natural quiet and

opportunities for solitude and quiet contemplation away from roads. Facilities and trails would be

designed to assure that paths of travel, viewpoints, benches and interpretive signage offer all visitors

a quality and meaningful experience while in the Grove.

Universally accessible facilities would comply with Architectural Barriers Act Accessibility Standards

(ABAAS) and NPS Director’s Order 42: Accessibility for Visitors with Disabilities in National Park

Service Programs and Services. The design of universally accessible trails is guided by the

Accessibility Guidelines for Outdoor Developed Areas.

Convert Southern Portion of the Upper Grove Loop Road to a Pedestrian Trail – All action

alternatives would allow for the conversion of the southern portion of the currently paved historic

loop road to a pedestrian trail. This portion of the loop has a remarkable density of giant sequoias

and would be an exceptional pedestrian pathway.

Final Environmental Impact Statement  2­7 October 2013

Chapter 2: Alternatives
       

               

   

   

                           

                           

                                

                               

                       

    

                         

                         

  

                         

                             

                           

                           

                         

                 

                           

                   

                             

                               

         

Alternative 1: No Action

Restoration of the Mariposa Grove of Giant Sequoias

Convert the Mariposa Grove Road from the Intersection with the Loop Road (near the

Museum) to Wawona Point into a Hardened Pedestrian Trail – The segment of the Mariposa

Grove Road extending from the intersection with the loop road in the vicinity of the Museum to

Wawona Point would be converted into a hardened trail but would allow for occasional use by

service vehicles, including those needing access to the telecommunications equipment located at

Wawona Point.

Extend Footbridge – An existing non­historic pedestrian bridge in the vicinity of the Fallen

Monarch would be removed and replaced with an extended footbridge to reduce impacts on stream

flow.

Museum Building – The museum building would remain, however, its use as a primary interpretive

facility would be moved to the new hub location under each action alternative. The museum building

may be repurposed as a group hiker’s shelter, meeting room, or other compatible use.

Improve Visitor Education and Interpretation – Interpretive signage in the Grove was updated in

2009. All action alternatives would implement further measures to better educate Mariposa Grove

visitors with additional interpretive waysides, orientation, and informational exhibits and a visitor

contact station. All action alternatives would include interpretation of historic and cultural uses in

the Grove including American Indian traditional cultural resources and practices.

Monitor Project Success – Develop a monitoring plan prior to project implementation to define the

target forest condition and metrics for evaluating the success of restoration efforts as well as defining

targeted conditions for the visitor experience.

Final Environmental Impact Statement  2­8 October 2013

Chapter 2: Alternatives
Final Environmental Impact Statement 

Final Environmental Impact Statement 

Final Environmental Impact Statement 

           

               

   

   

       

                         

                         

                         

                               

                       

                   

                   

                         

                             

                         

                           

                           

                               

                                 

                 

                           

                                 

                             

                               

                                     

                               

                           

                                   

                             

                                     

    

                           

                             

                               

                             

                           

                                 

                                   

                                 

                               

                               

           

                             

                           

                             

                               

                               

                               

                                 

                             

Alternative 2: South Entrance Hub (Preferred Alternative)

Restoration of the Mariposa Grove of Giant Sequoias

ALTERNATIVE 2: SOUTH ENTRANCE HUB (PREFERRED ALTERNATIVE)

Alternative 2, South Entrance Hub, is the park’s preferred alternative. Under this alternative, most

public parking, the gift shop, and the concessioner­operated commercial tram staging area and tram

operations would be removed from Mariposa Grove. Impervious surfaces within the Grove would

be minimized, and all areas from which buildings or pavement would be removed and that are not

slated for reuse would be ecologically restored natural habitat. Following removal activities,

ecological restoration measures would include soil preparation (e.g., decompaction), surface

contouring to match local topography, and planting the site with appropriate native vegetation.

Visitor parking would be relocated to the park’s South Entrance, which would serve as the primary

transit hub and contact area for Grove visitors. New visitor services would be provided including

visitor information and educational and other sales items. Removal of infrastructure from the lower

Grove area, selective tree clearing, and development of accessible trails would allow for restoration

of wetlands, soundscapes, and giant sequoia habitat, and would greatly enhance the importance of

the lower Grove area and Grizzly Giant as a primary destination point for experiencing the sequoias

within the Grove. An overview of the principal components of Alternative 2 is shown in figure 2­5,

and details are depicted in figures 2­6 through 2­8.

The South Entrance area would be reconfigured as a hub with the main parking area for Mariposa

Grove and a visitor contact area, as shown in figure 2­6. Parking at the South Entrance would be

expanded from 20 spaces to a total of 295 standard, oversize, accessible, and shuttle/bus parking

spaces. The size of the parking lot at South Entrance considers the proposed removal of 115 parking

spaces from the lower Grove area as well as the relocation of shuttle parking in the vicinity of the

Wawona store (over 100 vehicles during peak use periods). Parking capacity estimates for all of the

action alternatives would accommodate the existing level of visitation at the Grove on high­use days.

A retaining wall may be constructed on the uphill side of the current South Entrance parking area to

accommodate additional parking and allow for revegetation of the cut slope. A shuttle bus boarding

and tour bus transfer area would facilitate visitor use of the park shuttle service to travel to the lower

Grove area.

Commercial buses would stop at the South Entrance for visitor orientation, use of restrooms, and

transfer to shuttles. Depending on facility capacity and shuttle operations, buses less than 40 feet

long may drop off passengers in lower Grove area and park at South Entrance. To provide

pedestrian access from the South Entrance to the lower Grove area, the segment of the abandoned

Washburn Road alignment from the South Entrance to the Mariposa Grove Road picnic area would

be cleared of vegetation and rehabilitated as a pedestrian trail. At least two trail bridges would be

needed to cross streams, one in the vicinity of the parking area at South Entrance and one near the

entrance to the Grove. Where the Washburn Road ends near the existing picnic area, a new trail

would be constructed south of the Mariposa Grove Road from the picnic area to the lower Grove

area (shown on figure 2­5). The total trail length between the South Entrance and the lower Grove

area would be about 2 miles.

The shuttle service to the Grove would continue to operate between the South Entrance and the

lower Grove area. A separate, limited schedule shuttle would connect visitors staying at Wawona,

including the hotel and campground, with the South Entrance area where they would be able to

catch a shuttle to the Grove. Outside of normal shuttle hours and during the shoulder seasons, when

the shuttles are not running, visitors would be provided vehicular access to the lower Grove area

where parking for 50­80 vehicles would be available in either the transit turn­around area or the

picnic area along Mariposa Grove Road. The potential for early morning as well as late­day use of

the spaces would be contingent upon the hours of shuttle operation. Only placarded or service

Final Environmental Impact Statement 2­12 October 2013

Chapter 2: Alternatives
           

               

   

   

                                 

                             

                       

                                       

                                     

                          

                                 

                           

                             

                             

                         

                         

                                   

                         

                             

           

                               

                                 

                           

                           

                                 

                           

                    

                               

                             

                         

                               

                                   

                               

                         

                         

                           

                         

                 

                               

                                     

                               

                                   

      

Alternative 2: South Entrance Hub (Preferred Alternative)

Restoration of the Mariposa Grove of Giant Sequoias

vehicles would be provided access to the Grizzly Giant. Traffic control related to the closure of the

Mariposa Grove Road and lower Grove parking lot during periods of heavy visitation in the

shoulder/winter season (typically weekends and on holidays) would continue. During these periods,

visitors who are turned away when the lot is full in the Grove would be able to park at the South 

Entrance and walk into the Grove. When the lot is full, visitors would be directed to other areas of

the park. Road closures because of snow conditions in the winter would continue.

The current tram ticketing and turn­around area in the lower Grove would be repurposed as part of

a transit node which would also accommodate shuttle and school bus loading and unloading, and

accessible parking for placarded private vehicles; these facilities would be located in the vicinity of

the current development footprint (see figure 2­7). An accessible trail would be developed in the

ecologically restored lower Grove area, and would require some vegetation clearing, grading, and

surface hardening. Designated accessible parking spaces would be provided at both the lower Grove

area and in the vicinity of the Grizzly Giant, but away from the existing giant sequoias. An accessible

trail would be constructed connecting the Grizzly Giant with the proposed nearby accessible parking

area (figure 2­8). Other trails would provide opportunities to experience the solitude of the giant

sequoias in the upper Grove area.

The NPS is also exploring options for realigning the entrance to the Grove to enhance restoration

efforts and straighten the existing tight curve near the giant sequoias in the vicinity of the Three

Sentinels. This work would likely be completed in conjunction with the resurfacing of the Mariposa

Grove Road between South Entrance and the Grove. The potential road realignment is shown on

figure 2­7. The crossing over the creek (e.g., box culvert or bridge) would be relocated to improve

safety, control erosion of the drainage channel, and avoid giant sequoias. Crossing design and

construction would minimize impacts on nearby giant sequoias and wetlands.

Within the Mariposa Grove, the paved road between the Grizzly Giant and Wawona Point would be

narrowed and maintained as a hardened trail for pedestrian use and limited service vehicle access.

Service access is needed beyond the Grizzly Giant to maintain communications equipment at

Wawona Point, and the comfort stations and leach field in the upper Grove area. The short section

of road between the lower Grove area and the Grizzly Giant would be signed to encourage visitors to

use the pedestrian trail instead of the road. This would help separate the pedestrians from the

vehicles with accessible parking placards driving to the Grizzly Giant. The portion of the hardened

trail to Wawona Point would undergo drainage improvements, including repair or replacement of

existing culverts and minor grading to establish outsloping to improve surface sheet flow and reduce

channelization and diversion of water outside the Grove watershed. To the maximum extent

practicable, historic road prisms and materials would be retained.

The water supply treatment unit and storage tank currently located along the loop road would be

relocated to in the vicinity of the intersection of the loop road and the road to Wawona Point to

eliminate the need for maintenance vehicle access along that segment of the loop road. The loop

road surfacing would be removed and a hiking trail constructed that would be between 4 and 8 feet

wide (figure 2­5).

Final Environmental Impact Statement 2­13 October 2013

Chapter 2: Alternatives
Final Environmental Impact Statement 

Final Environmental Impact Statement 

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Final Environmental Impact Statement 

           

               

   

   

                     

                         

                               

                           

                             

                           

                             

                                   

                         

                             

                                   

                     

                               

                         

                           

       

                                 

                     

                           

                               

                                   

                                   

                                   

   

     

                           

                               

                         

                               

                           

                             

                         

                     

                               

                             

                           

                       

                       

                           

           

               

                         

                               

                         

                             

Alternative 2: South Entrance Hub (Preferred Alternative)

Restoration of the Mariposa Grove of Giant Sequoias

Pending geotechnical assessments, new septic systems and leach fields would be installed at both the

South Entrance and the lower Grove area to accommodate flush toilets to the extent practicable. The

final locations of the new leach fields would be determined based on further analysis of resource and

topographic constraints. The installation of a septic system in the lower Grove area would be

contingent upon additional soil surveys; an additional option is installation of a sewer line between

the Grove and the South Entrance that would be located within the Mariposa Grove road right­ofway. Each leach field option would require the allocation of a 100% replacement area to be set aside

for future use at the time the constructed leach field reaches the end of its life cycle. The leach field

would require between 2.16 and 3.54 acres, including the 100% replacement area set­aside.

Replacement areas would not need to be constructed at the same time as the designated leach fields,

but must be set aside for future use. Options for the leach field locations are identified on the figures,

however final locations are contingent upon additional geotechnical investigation and would be

identified based on feasibility related to soil conditions and to avoid or minimize impacts on sensitive

resources including archeological sites. The final determination of flush or vault fixtures would be

contingent on the feasibility of the septic system and leach field based on the continuing

investigation of site­specific conditions.

At the upper Grove area comfort station, the leach field would be replaced in an area outside of

sequoia habitat. The water supply pipeline would be repaired or replaced.

Two non­historic trail segments would be removed under Alternative 2: a section just above the

Grizzly Giant that parallels the Mariposa Grove Road and a segment that extends from the southern

end of the upper Grove loop road northwestward to a point below and west of Wawona Point. As

noted above, a 2/3 mile long segment of the historic loop road in the upper Grove would be

converted to a pedestrian trail 4 to 8 feet wide. Existing equestrian trails would not be impacted by

the project.

Wawona Road/Mariposa Grove Road Intersection

Under Alternative 2, the park would reconstruct and possibly realign the intersection of Wawona

Road and Mariposa Grove Road (figure 2­6) if traffic conditions warrant. This would affect up to

1,100 feet of road beginning on Wawona Road approximately 200 feet south of its intersection with 

Mariposa Grove Road, and ending approximately 400 feet west on Wawona Road and 200 feet east

on Mariposa Grove Road beyond the existing comfort station parking. A roundabout would be

explored if the proposed kiosk improvements at the South Entrance (to be implemented in 2013) do

not adequately address congestion for visitors coming into the South Entrance from Fish Camp. A

proposed roundabout would be optimally located for the site conditions and roadway requirements

and would have a 120­foot outside diameter to accommodate the existing type and volume of traffic

using the intersection. There would be one lane of traffic in a counter­clockwise direction with an

inner concrete paved circle with a mountable curb. The center of the roundabout could be

revegetated. Realignment of the intersection is intended to reduce risk of collisions, better

accommodate larger vehicles, increase the intersection’s vehicle traffic capacity, improve clarity of

way finding and travel directions for visitors, reduce traffic congestion at the intersection, and

improve working conditions for NPS staff.

Accessibility

Under Alternative 2, integrated, universally accessible (ABAAS compliant) transportation

hubs/nodes, parking spaces, comfort stations, interpretive signs and displays, and trails at the South 

Entrance Station and lower portion of the Grove would allow park visitors with a greater range of

physical abilities to experience and enjoy the Mariposa Grove. Visitors with vehicles displaying

accessible parking placards or NPS service vehicles would drive through the lower Grove area to the

Final Environmental Impact Statement  2­18 October 2013

Chapter 2: Alternatives
           

               

   

   

                               

                           

                             

                               

                       

  

                     

                     

                         

                     

                       

                         

                   

                               

                               

                           

                               

                                

                         

                                 

                           

                               

                             

  

                       

                                 

                             

                                     

                               

                                 

                               

                             

                             

    

Alternative 2: South Entrance Hub (Preferred Alternative)

Restoration of the Mariposa Grove of Giant Sequoias

Grizzly Giant. Several pullouts would be installed to allow these visitors to stop and view individual

sequoias or groups of sequoias such as the Bachelor and Three Graces. Accessible parking spaces

would be available at the lower Grove area and Grizzly Giant for visitors with accessible parking

placards, and the existing vault toilet would be relocated to the Grizzly Giant parking area. The

shuttle originating at the South Entrance would continue to be available to visitors with limited

mobility.

Accessibility improvements (consistent with ABAAS) would be made to the approach to the existing

South Entrance comfort station, which is a contributing feature to the South Entrance historic

district. Any alterations would be designed to meet the Secretary of the Interior’s rehabilitation

treatment standard for historic properties. Historic materials would be salvaged and reintegrated,

and character­defining stonework would be retained. Thresholds would be affected only to the

extent necessary to allow for universal access, and modifications would be implemented per

Secretary of the Interior’s Standards for the Treatment of Historic Properties.

Additional accessible trails are proposed in the lower Grove area that would allow visitors of all

abilities the opportunity to enjoy the beauty and tranquility of Yosemite’s giant sequoia forest in a

less crowded, more peaceful setting than is available under current conditions. Under Alternative 2,

an accessible trail would be created in the ecologically restored lower portion of the Grove that

would include boardwalks, benches and viewing areas outside of paths of travel (see figure 2­7). The

loop trails would enable all visitors, including those in wheelchairs or with otherwise limited

mobility, to move beyond the activity of the parking and shuttle boarding area and into the Grove.

Visitors could experience the beauty of the giant sequoias, including the Fallen Monarch, wetlands,

streams, and wildlife at their own pace and in a more natural setting. Specific accessible trail

alignments will be refined based on site conditions and to maximize use of previously disturbed

areas.

A similarly accessible, approximately 2,000­foot­long trail would be built and would include portions

of a previously abandoned trail and existing trails to the Grizzly Giant (see figure 2­8). This trail

would extend beyond the Grizzly Giant for approximately 400 feet to the California Tunnel Tree,

and then beyond for just over 300 feet to an open overlook on a small ridge between two streams.

The overlook would offer visitors a glimpse of the landscape context of the Grove; the hillslopes,

forest, wetlands and streams that comprise the habitat of the giant sequoias. A trail leading to the

adjacent Sierra National Forest is also located at the Grizzly Giant trailhead where the new accessible

parking spaces would be located. A potential accessible trail extension could start here, and would

wind through forest, past a massive granite outcrop, to a small wetland within the park boundary (see

figure 2­8).

Final Environmental Impact Statement  2­19 October 2013

Chapter 2: Alternatives
         

               

   

   

     

                             

                           

                         

                                 

                               

                                 

                             

                                   

                        

                               

                                     

                           

                                       

                           

                           

                                 

                                 

                        

                                 

                           

                       

                                     

                           

           

                           

                               

                                   

                           

     

                         

                             

                       

                           

   

                         

                             

                                    

                               

                         

                     

                       

Alternative 3: Grizzly Giant Hub

Restoration of the Mariposa Grove of Giant Sequoias

ALTERNATIVE 3: GRIZZLY GIANT HUB

Alternative 3, Grizzly Giant Hub, would include removal of the Mariposa Grove parking lot, gift

shop, and commercial tram staging area and operations to allow for comprehensive restoration of

wetlands, soundscapes, and giant sequoia habitat. Under Alternative 3, a new Grove bypass road,

including two bridges, would be routed south of the current Grove access road to a new parking lot

southwest of the Grizzly Giant, and outside of giant sequoia habitat (figures 2­9 through 2­11). The

new parking area at Grizzly Giant would serve as the primary departure point for visitors wishing to

enter the Grove and would be open to all private vehicles (including recreational vehicles and

trailers) and buses. At the Grizzly Giant Hub, vault toilets would be used due to the infeasibility and

high cost of delivering water to, and disposing of wastewater at, this location.

The roadway between the Grizzly Giant and Wawona Point area would be converted to a hardened

trail between 10 to 12 feet wide. Service vehicles would still use the hardened trail for access to the

telecommunications facilities at Wawona Point and other facilities in the upper Grove area. The

existing road from the lower Grove area to the Grizzly Giant area would be converted to a trail that is

between 4 and 8 feet wide. The remaining road would undergo drainage improvements, including

cleaning of existing culverts and installation of new culverts to improve water infiltration and

prevent diversion of water outside the Grove. Vault toilets along the road within the Grove would be

removed. Similar to Alternative 2, a 2/3 mile long segment of the loop road above the Mariposa

Grove Museum would be converted into a 4­ to 8­foot­wide pedestrian trail.

The current parking lot in the lower Grove area would be removed. Transit service to the Grove

from the South Entrance would be discontinued, and the commercial tram would no longer operate.

A significantly smaller parking lot providing up to ten ABAAS­compliant accessible parking spaces,

trailhead, and loop trail at the lower Grove area, and a new accessible trail at the Grizzly Giant would

serve visitors with disabilities. Other visitors could choose to explore the lower Grove area using

existing trails near the Grizzly Giant.

Two non­historic trail segments would be removed under Alternative 3: a section just above the

Grizzly Giant that parallels the Mariposa Grove Road, and a segment that extends from the southern

end of the upper Grove loop road northwestward to a point below and west of Wawona Point. Other

trails within the Grove with connections to Wawona and south and east to Sierra National Forest

land would remain.

The new bypass road build­out footprint would be 2.20 acres, primarily through non­giant sequoia

forest. Approximately 0.33 acre would be in identified giant sequoia forest, and 0.10 acre would be

raised crossings over wetlands. Under Alternative 3, the current Wawona Road/Mariposa Grove

Road T­intersection would be retained, and would be the same as described for Alternative 1

(No Action).

Accessibility

Under Alternative 3, ten ABAAS­compliant parking spaces, trailhead, and loop trail would be

developed at the lower Grove area. An additional seven accessible parking spaces would be provided

at the main hub at Grizzly Giant, as well as a new accessible trail to the Grizzly Giant.

Alternatives 2 and 3 both provide accessible trails from the lower Grove area and Grizzly Giant, but

Alternative 3 would not provide for additional potential accessible trail development at these

locations. Under Alternative 3, accessible facilities would remain unchanged at the South Entrance

and the shuttle that accommodated visitors with limited mobility would no longer operate.

Final Environmental Impact Statement  2­20 October 2013

Chapter 2: Alternatives
         

               

   

   

       

Alternative 3: Grizzly Giant Hub

Restoration of the Mariposa Grove of Giant Sequoias

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Final Environmental Impact Statement  2­21 October 2013

Chapter 2: Alternatives
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Alternative 4: South Entrance Hub with Modified Commercial Tram Service

Restoration of the Mariposa Grove of Giant Sequoias

ALTERNATIVE 4: SOUTH ENTRANCE HUB WITH MODIFIED COMMERCIAL TRAM

SERVICE

Alternative 4, South Entrance Hub with Modified Commercial Tram Service, would remove most

public parking, the gift shop, and commercial tram staging from Mariposa Grove, and relocate the

parking and tram staging to the park’s South Entrance. New visitor services would be provided at the

South Entrance including visitor information and educational and other sales items. Previously

developed areas not slated for reuse would undergo ecological restoration of wetlands and giant

sequoia habitat, similar to that described for Alternative 2. An overview of the principal components

of Alternative 4 is shown in figure 2­12, and details are depicted in figures 2­13 through 2­15.

Under Alternative 4, visitor parking would be relocated to South Entrance east of Wawona Road and

south of the Mariposa Grove Road (figures 2­12 and 2­13). The proposed configuration at the South 

Entrance as the primary arrival node would be very similar to Alternative 2. However, the

commercial tram tour would operate from the South Entrance, with stops at the lower and mid

Grove areas, and end in the vicinity of the Mariposa Grove Museum. To obtain a balance between

visitor access and opportunities for quiet and solitude in the upper portion of the Grove, the hours of

operation for the tram would be reduced.

Shuttle service would also continue to operate as a free service between the South Entrance and the

lower area of the Grove. Under Alternative 4, the shuttle and the commercial tram would share the

same road from South Entrance to the lower Grove area. In addition, a shuttle with a more limited

schedule than existing conditions would connect visitors staying at Wawona, including the Hotel

and campground, with the South Entrance. Commercial bus activity would occur in the same

manner as proposed under Alternative 2, with buses greater than 40 feet long stopping at South 

Entrance for transfer to shuttle. Depending on facility capacity and shuttle operations, buses less

than 40 feet long may drop off passengers in lower Grove area and park at South Entrance.

The paved road through Mariposa Grove would undergo drainage improvements, including

installation of new culverts to improve sheet flows and reduce channelization and diversion of water

out of the Grove watershed. The short section of road below the Grizzly Giant would be signed to

encourage visitors to use the pedestrian trail instead of the road. This would help separate

pedestrians from vehicles. The paved road would be maintained to the historic museum building and

restroom in the upper portion of the Grove, and tram service would transport visitors to the upper

Grove along this road. Similar to the other action alternatives, a 2/3 mile long segment of the loop

road in the upper Grove area would be converted into a 4­ to 8­foot wide trail.

Pending geotechnical assessments, new septic systems and leach fields would be installed at both the

South Entrance and the lower Grove area to accommodate flush toilets to the extent practicable. The

final locations of the new leach fields would be determined based on further analysis of resource and

topographic constraints. The installation of septic in the lower Grove area would be contingent upon

additional soil surveys; an additional option is installation of a sewer line between the Grove and the

South Entrance that would be located within the Mariposa Grove road right­of­way. Each leach field

option would require the allocation of a 100% replacement area to be set aside for future use at the

time the constructed leach field reaches the end of its life cycle. The leach field would require

between 2.16 and 3.54 acres, including the 100% replacement area set­aside. Replacement areas

would not need to be constructed at the same time as the designated leach fields, but must be set

aside for future use. Options for the leach field locations are identified on the figures, however final

locations are contingent upon additional geotechnical investigation and would be identified based

on feasibility related to soil conditions and to avoid or minimize impacts on sensitive resources

Final Environmental Impact Statement  2­25 October 2013

Chapter 2: Alternatives
                   

               

   

   

                       

                             

   

                     

                             

                       

                       

                       

                      

                           

                                 

                           

                             

                

     

                           

                                 

                       

                             

                         

                           

                             

                               

                               

                               

                 

                             

                   

                               

                                 

                                 

                               

                             

                             

                             

                

                       

                               

                 

Alternative 4: South Entrance Hub with Modified Commercial Tram Service

Restoration of the Mariposa Grove of Giant Sequoias

including archeological sites. The final determination of flush or vault fixtures would be contingent

on the feasibility of the septic system and leach field based on the continuing investigation of sitespecific conditions.

Path­of­travel accessibility improvements would be made to the historic comfort stations at the

South Entrance and in the upper Grove area. Modifications would be designed to meet the Secretary

of the Interior’s rehabilitation treatment standard for historic properties. Historic materials, such as

any character­defining stonework along the existing paths to the comfort stations, would be

incorporated into the upgraded accessible paths­of­travel. The upper Grove leach field would be

renovated, and the leaking water line would be repaired or replaced.

One non­historic trail segment would be removed under Alternative 4: a section that extends from

the southern end of the upper Grove loop road northwestward to a point below and west of

Wawona Point. Because of occasional commercial tram use of the Mariposa Grove Road, the nonhistoric trail segment proposed for removal under Alternative 2 would remain under Alternative 4 to

give pedestrians a vehicle­free option above the Grizzly Giant.

Wawona Road/Mariposa Grove Road Intersection

Under Alternative 4, the park would reconstruct and possibly realign the intersection of Wawona

Road and Mariposa Grove Road (figure 2­13). This would include up to 1,100 feet of road beginning

on Wawona Road approximately 200 feet south of the intersection with Mariposa Grove Road, and

ending approximately 400 feet west on Wawona Road and 200 feet east on Mariposa Grove Road

beyond the existing comfort station parking. Under Alternative 4, the T­intersection would be

shifted to the northwest, making the entrance into the park a through movement directly toward

Wawona and Yosemite Valley destinations, and allowing a right turn onto the Mariposa Grove Road

as the minor intersecting roadway. A protected left turn lane for traffic coming from Yosemite Valley

and headed toward Mariposa Grove would be provided. This would widen the existing exit lane to

three lanes: one in each direction and a turning lane. Realignment of the intersection is intended to

reduce accident risks, better accommodate larger vehicles, increase the intersection’s through­traffic

capacity, improve clarity of way finding and travel directions for visitors, reduce traffic congestion at

the intersection, and improve working conditions for Yosemite National Park staff.

Accessibility

Under Alternative 4, placarded vehicles would be able to drive beyond the Grizzly Giant into the

vicinity of the Museum in the upper Grove area. Accessible parking spaces would be provided at the

upper Grove (4 spaces) as well as Grizzly Giant (4), lower Grove area (6), and South Entrance (8).

The tram would also be available for visitors with limited mobility from the South Entrance to the

upper Grove, with several stops in between. Visitors would be able to experience the mid­Grove area

from an accessible overlook; unlike Alternatives 2 and 3, an accessible trail would not be constructed

under Alternative 4. The shuttle originating at the South Entrance would also be available to visitors

with limited mobility to take to the lower Grove.

Accessibility improvements would be made at the South Entrance, lower Grove area, and upper

Grove. An accessible trail would be constructed in the ecologically restored lower Grove area, and an

accessible overlook would be provided near the Grizzly Giant.

Final Environmental Impact Statement  2­26 October 2013

Chapter 2: Alternatives
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Alternatives Considered but Dismissed from Further Analysis

Restoration of the Mariposa Grove of Giant Sequoias

ALTERNATIVES CONSIDERED BUT DISMISSED FROM FURTHER ANALYSIS

Under the National Environmental Policy Act (NEPA), an alternative may be eliminated

from detailed study for the following reasons (Title 40 Code of Federal Regulations [CFR]

Part 1504.14 (a)):

•	 Technical or economic infeasibility

•	 Inability to meet project objectives or resolve need for the project

•	 Duplication of other less environmentally damaging alternatives

•	 Conflicts with a current, valid plan, statement of purpose and significance, or other policy;

and therefore, would require a major change in that plan or policy to implement

•	 Environmental impacts are too great

The following alternatives and options were considered during the preliminary design phase of the

Mariposa Grove of Giant Sequoias restoration project; because they met one or more of the above

criteria, they were eliminated from detailed analysis in this EIS.

Lower Grove Area Hub

This alternative was developed to explore low­cost changes that might make a significant difference

in resolving the major issues at the Mariposa Grove. In this alternative, the commercial tram would

be removed, the Mariposa Grove parking lot would have a smaller footprint, and modest giant

sequoia habitat restoration could be achieved in the lower Grove area that would improve existing

conditions. An accessible trail could be constructed, and restroom accessibility at the lower Grove

area could be greatly improved. This conceptual alternative had an accessible viewpoint overlooking

the Grizzly Giant, but no accessible trails. The primary arrival point and contact area for visitors

would have remained in the lower Grove area, and access and parking would remain fragmented at

the Grove, South Entrance, and Wawona. The alternative, though offering some restoration

opportunities, did not adequately address the purpose and need components associated with the

sustained overflow parking problems at South Entrance and the subsequent adverse impact on

visitor access times and visitor experience. In addition, lower Grove area buildings and infrastructure

that are currently adversely impacting giant sequoias as well as other sensitive resources such as

wetlands would have remained under this alternative. Therefore, because this alternative did not

adequately meet the project purpose and need, it was dismissed from further analysis.

South Entrance Hub, Complete Commercial Tram Road Removal, Relocate Wawona

Point Communications Equipment

This alternative was developed to provide extensive giant sequoia habitat restoration by completely

removing and restoring the existing commercial tram/service road from the lower Grove area to

Wawona Point, including the upper Grove area loop road. Other aspects of this alternative were

essentially the same as the Alternative 2, South Entrance Hub. To eliminate the service road, the NPS

would have had to relocate the recently installed communications tower at Wawona Point. The

location of the Wawona Point communications tower is a critical component of the park­wide

communications network. The tower requires periodic maintenance (e.g., refueling) throughout the

year, and therefore must be accessible via a roadway for service vehicles.

Final Environmental Impact Statement  2­31 October 2013

Chapter 2: Alternatives
             

               

   

   

                             

                       

                           

                       

                                   

                     

                       

                           

                             

                           

                           

                         

                         

  

   

                         

                         

                         

                               

                           

                             

       

                         

                             

                               

                       

                         

                                     

  

           

                               

                         

                           

                                 

                       

                             

                         

                             

                                 

                               

                                 

                           

                           

                           

                             

                   

Alternatives Considered but Dismissed from Further Analysis

Restoration of the Mariposa Grove of Giant Sequoias

The park reviewed possible sites for tower relocation, but the only suitable alternate location lies

within designated wilderness, and relocation costs would be prohibitive, possibly exceeding several

million dollars. The project team also considered alternate power supply for the Wawona Point

equipment, but determined that new power transmission lines would cross designated wilderness,

solar panels would be unreliable in the winter due to snow cover, and delivery of propane via other

transportation modes (e.g., helicopter) during winter months would require extensive site

preparation and would be expensive and unreliable during inclement weather. Because the

communications tower and the current fueling system could not reasonably be relocated or replaced,

the “full” restoration benefits envisioned in this alternative could not be realized, and the alternative

ended up being nearly identical to Alternative 2: South Entrance Hub. Therefore, this alternative was

dismissed from further analysis. Under the retained action alternatives, the road to Wawona Point

would continue to be maintained for occasional vehicular use until the telecommunications tower

becomes obsolete due to technological advances, after which more permeable trail surfaces may be

explored.

Studhorse Parking

NPS considered adding supplemental parking at the Studhorse parking area located on Wawona

Road between Wawona and the South Entrance, to support visitation at the Mariposa Grove.

However, the area’s proximity to designated wilderness and topographic constraints made a new

large parking lot infeasible in the area. In addition, the South Entrance area, being in closer proximity

to the Grove, provides more logical centralized placement for Grove visitor parking. Therefore, this

area was dismissed as a possible parking component of the alternatives, and was not evaluated

further.

Sierra National Forest Parking Siting

NPS considered collaborating with the U.S. Department of Agriculture, Forest Service to create a

collection/parking hub and visitor contact area for Mariposa Grove in the Goat Meadow snow play

area on Sierra National Forest land, or using Sierra National Forest land for road access. Extensive

issues with road widening and fee collection were identified. Complications of planning and

managing an out­of­park site with multiple jurisdictions, and a desire to have parking and other

visitor facilities closer to the Grove and within the boundaries of the park, led to the dismissal of this

option.

New Parking at South Entrance West of Wawona Road

The option to develop new parking on the west side of Wawona Road, near the Wawona Road/

Mariposa Grove Road intersection, was considered. Initial analysis indicated this option would be

problematic in terms of topography, visitor orientation, traffic flow, and pedestrian safety. The main

concerns were the safety of entrances and exits on the Wawona Road curve and the safety of

pedestrians crossing the highway. A possible vehicle or pedestrian underpass beneath Wawona Road

was considered to mitigate some of the safety concerns, but the cost associated with a grade

separation at this location, coupled with the difficulty in maintaining efficient operations at the South 

Entrance due to parking congestion, led to dismissal of this alternative. Operational issues were also

a concern, as the park service ranger shooting range would be close to the proposed visitor parking.

Parking on the east side of the road is more intuitive for people going eastward from South Entrance

to Mariposa Grove and allows for a simpler transition for people entering the park from the south.

This option also would displace the existing septic system and leach field at South Entrance. The

possibility of routing wastewater from South Entrance to the Wawona treatment plant via a new

sewer line that would be constructed along Wawona Road also was considered for all alternatives.

However, the 7­mile­long sewer line was determined to be cost­prohibitive at an estimated cost of

$12 million to $14 million, and this option was dismissed.

Final Environmental Impact Statement  2­32 October 2013

Chapter 2: Alternatives
             

               

   

   

       

                             

                   

                                   

                             

                           

                           

                             

                         

                       

                                 

                   

               

                               

   

                   

                       

                   

                       

                           

                     

                       

                           

                           

                                 

   

                       

                       

                       

                     

                             

                     

                       

                             

                     

                       

                               

                         

                     

Alternatives Considered but Dismissed from Further Analysis

Restoration of the Mariposa Grove of Giant Sequoias

Oakhurst or Fish Camp Parking and Visitor Contact

Developing a visitor contact area (similar to that in Mariposa) and possible parking outside park

boundaries in Fish Camp or Oakhurst was considered. Complexities with land and building

ownership outside the park and a desire to have visitor facilities for the Mariposa Grove closer to the

Grove and within the boundaries of the park led to the dismissal of this option.

MITIGATION MEASURES

The NPS places a strong emphasis on avoidance, minimization, and mitigation of adverse impacts

under NEPA, and adverse effects under the National Historic Preservation Act (NHPA). To help

ensure that project activities protect natural, cultural, and social resources and the quality of the

visitor experience, mitigation measures have been developed that would be implemented as part of

the action alternatives (see Appendix E: Mitigation Measures). These mitigation measures would

occur prior to, during, and after implementation of all proposed actions in Alternatives 2, 3, and 4.

Additional mitigation measures may be identified through consultation with the California State

Historic Preservation Officer (SHPO) and implemented through a project­specific Memorandum of

Agreement, as required under 36 CFR Part 800. All the mitigation measures are considered to be

integral to each alternative.

ENVIRONMENTALLY PREFERRED ALTERNATIVE

In accordance with NPS Director’s Order 12: Conservation Planning, Environmental Impact Analysis,

and Decision­making and Council on Environmental Quality requirements, the NPS is required to

identify the “environmentally preferred alternative” in all environmental documents, including EISs.

The environmentally preferred alternative is determined by applying the criteria listed in NEPA

Sec. 101(b). The Council on Environmental Quality (46 Federal Register 18026­18038) states that the

“environmentally preferable alternative is the alternative that would promote the national

environmental policy as expressed in NEPA’s Section 101.” Generally, the environmentally preferred

alternative is the alternative that causes the least damage to the biological and physical environment

and that best protects, preserves, and enhances historic, cultural, and natural resources (46 Federal

Register 18026 – 46 Federal Register 18038). Per Section 101 of NEPA, it is the responsibility of the

federal government to:

(1) Fulfill the responsibilities of each generation as trustee of the environment for succeeding

generations.

All of the action alternatives would, to varying degrees, reduce development footprints

within the Mariposa Grove, restore hydrologic and ecological systems to more natural

conditions, and stabilize, and/or rehabilitate cultural resources at South Entrance, the Grove,

and Wawona Point. Alternative 2 best meets goal 1 because it would reduce developed area

within sequoia habitat; require the least new development outside sequoia habitat;

implement substantial restoration of wetlands and giant sequoia habitat; and better protect

Pacific fishers from road fatalities on the Mariposa Grove Road and within the Grove. The

project would also improve the soundscape throughout the Grove by eliminating most

private vehicle parking in the lower Grove area during peak­use periods and discontinuing

operation of the commercial tram in the upper Grove area. All of these actions would address

visitor and operational services that are adversely affecting giant sequoia habitat and provide

the best opportunity for sustaining the long­term health of the Mariposa Grove.

Final Environmental Impact Statement  2­33 October 2013

Chapter 2: Alternatives
     

               

   

   

                       

                                 

                         

                           

                             

                           

                     

                           

                             

                     

                           

                         

                           

           

                           

                     

                     

                           

                       

                       

                       

                   

                             

                         

                       

                 

   

                           

                         

                              

                             

                       

                             

                       

                     

                               

                       

               

                       

                       

                         

                     

                           

                             

Environmentally Preferred Alternative

Restoration of the Mariposa Grove of Giant Sequoias

(2) Assure for all visitors safe, healthful, productive, and aesthetically and culturally pleasing

surroundings.

All of the action alternatives would meet goal 2. Alternative 2 best fulfills this goal for several

of the reasons stated above, in conjunction with affording the best balance of more efficient

visitor transport via shuttle to and from the Grove and relocation of traffic­ and parkingrelated impacts outside of the Grove. Alternative 2 provides universal access to a quality giant

sequoia grove experience in the lower Grove while preserving a less developed, more natural

visitor experience in the upper Grove through elimination of the commercial tram

operations and reducing the footprint of trails and roadways. The short section of road

below the Grizzly Giant would be signed to encourage visitors to use the pedestrian trail

instead of the road. This would help separate pedestrians from vehicles with accessible

parking placards going to the Grizzly Giant. Alternative 2 assures a safe, productive, and

aesthetically and culturally pleasing environment for visitors to the Mariposa Grove of Giant

Sequoias.

(3) Attain the widest range of beneficial uses of the environment without degradation, risk to

health or safety, or other undesirable and unintended consequences.

Alternative 2 would attain the widest range of beneficial uses of the environment while

minimizing further degradation of the sensitive giant sequoia environment, and managing

risks to visitor health and safety concerns by eliminating vehicle/pedestrian conflicts within

the Grove. All of the action alternatives would improve sanitary facilities, and reduce current

safety hazards associated with Grove traffic, shuttle stops, and parking. Alternative 2 would

also improve visitor safety by separating hikers and pedestrians from roadway traffic,

eliminating the commercial tram service and redesigning parking areas and shuttle stops,

thereby reducing vehicle/pedestrian conflicts currently associated with shared use of the inGrove parking lot and roadway. The road below the Grizzly Giant would be signed to

encourage visitors to use the pedestrian trail to help separate pedestrians from vehicles.

(4) Preserve important historic, cultural, and natural aspects of our national heritage, and

maintain, wherever possible, an environment which supports diversity, and variety of

individual choice.

Alternative 2 would best restore and preserve the giant sequoias of the Mariposa Grove,

which are important to our national heritage and the development of both state and national

park systems. Alternatives 2 and 3 would provide a better opportunity for solitude in the

upper Grove area with the removal of the tram and private vehicles. All of the action

alternatives would avoid and/or minimize effects to historic and traditional cultural aspects

of the Grove and South Entrance areas; Alternative 3 would have the least effect on the

historic setting at South Entrance, but would sustain the most extensive disturbances on

archeological resources and alter historic circulation patterns within the Grove by

constructing a new road to a new visitor parking and information hub near the Grizzly Giant.

(5) Achieve a balance between population and resource use which will permit high standards of

living and a wide sharing of life’s amenities.

Alternative 2 would reduce in­Grove infrastructure. Alternative 2 best conserves energy by

significantly restricting private vehicle access to the Grove and eliminating commercial tram

operations within the Grove. All action alternatives improve accessibility to the Grove for

visitors with limited mobility. Alternative 2 offers the best opportunity for expanding the

range of visitor experiences by expanding accessible trail opportunities in diverse areas in the

lower Grove area and at Grizzly Giant. Alternatives 2 and 3 would provide a better

Final Environmental Impact Statement  2­34 October 2013

Chapter 2: Alternatives
     

               

   

   

                           

                       

           

                       

             

                   

                     

                   

                       

                        

                           

                      

                       

                      

Environmentally Preferred Alternative

Restoration of the Mariposa Grove of Giant Sequoias

opportunity for quiet, natural sounds, and solitude in the upper Grove with the removal of

the tram and private vehicles, enhance the quality of renewable resources and approach the

maximum attainable recycling of depletable resources.

All of the action alternatives would implement sustainable principles and technologies in

accordance with Guiding Principles of Sustainable Design (NPS 1993). Sustainable principles

and technologies would include recycling of demolition debris to the extent practicable,

using recycled materials in construction, repair or replacement of inefficient systems,

improved operational practices, and installation of energy­ and water­efficient features and

utilities. Alternative 2 represents the most efficient management of depletable fossil fuels

both by eliminating in­Grove tram operations, and most private vehicle access during peak

visitor season, and by concentrating visitor and employee parking near a park entrance and

implementing efficient shuttle service using buses that operate on alternative fuels.

On balance, Alternative 2 (the preferred alternative) best achieves these national environmental

policy goals, and therefore is identified as the environmentally preferred alternative.

Final Environmental Impact Statement  2­35 October 2013

Chapter 2: Alternatives
   

               

   

   

                         

                         

                         

                           

                     

                       

                           

                     

                           

                           

                         

                               

   

         

   

   

   

   

   

     

       

     

       

   

                               

                         

                                                 

                                           

                 

                                             

            

                           

          

Cost Estimates

Restoration of the Mariposa Grove of Giant Sequoias

COST ESTIMATES

The estimated costs of “hard construction” for each alternative, as understood at the 50­percent

schematic design development phase, were assembled using empirical market data and input from

vendors and industry professionals. These cost estimates present a relative comparison of costs

among the alternatives. The estimating process attempted to anticipate design and scope in advance

of the development of engineering, architectural detailing, inventory of existing conditions, and

topographical surveys. The estimate employed unit assembly costs extrapolated, in part, from

modeling data from similar completed projects. The unique nature and remote location of the

Mariposa Grove of Giant Sequoias, however, presented a challenge for identifying comparable

project data. Table 2­1 presents the preliminary cost estimates for construction costs. With regard to

the accuracy of the estimated costs, Alternative 3 has the most uncertainty since additional

geotechnical investigation would be needed to determine the costs of construction for a new

segment of road within the Grove. Unlike the action alternatives, the No Action Alternative has no

net construction costs.

Table 2­1 – Preliminary Cost Estimates

Action

Alternative 1:

No Action

Alternative 2:

South

Entrance Hub

Alternative 3:

Grizzly Giant

Hub

Alternative 4:

South Entrance

Hub with

Commercial 

Tram Operation

Facilities at South Entrance $ 0 $9,986,000 $ 0 $9,986,000

Facilities in Lower Grove Area $ 0 $1,317,000 $433,000 $1,578,000

Facilities at Grizzly Giant $ 0 $214,000 $3,819,000 $54,000

Facilities in Upper Grove Area $ 0 $547,000 $476,000 $498,000

Roads, Trails, and Restoration $ 0 $8,647,000 $18,070,000 $9,339,000

Construction Costs Existing conditions $20,711,000 $22,798,000 $21,455,000

Notes:

1)	 Construction of an optional bridge in the lower Grove area under Alternative 2 would require additional cost/design

analysis and compliance. A preliminary estimate for construction of the bridge is $4M.

2)	 If soil conditions in the lower Grove area are such that a septic system is not feasible, a sewer line would need to be

installed within the road prism and would add an additional $2M to the cost for Alternatives 2 and 4. Alternative 3 relies

on use of vault toilets at the Grizzly Giant.

3)	 50­year project life cycle costs assume a 2.2% discount rate (which refers to the interest rate used in discounted cash flow

SUMMARY OF ALTERNATIVES AND POTENTIAL IMPACTS

Table 2­2 presents a summary comparison of alternatives, and Table 2­3 summarizes build­out and

ecological restoration acreages by alternative.

Final Environmental Impact Statement  2­36 October 2013

Chapter 2: Alternatives
Proposed Project Action/Component Alternative 1: No­Action

Alternative 2: South Entrance Hub 

(Preferred Alternative) A

Ecological Restoration

Wetland restoration at lower Grove area with boardwalk No Common to all action alternatives CommRemove 115­car parking lot and other infrastructure in lower

Grove area

No Yes, but addition of 6 accessible and 25­50

parking spaces in new shuttle turnaroundfor when shuttle is not in operation

Yes, b

new d

Remove upper Grove area loop road/convert to trail No Common to all action alternatives CommInstall/repair/replace culverts to improve hydrology No Common to all action alternatives CommPrescribed fire and thinning within and surrounding the Grove Yes Common to all action alternatives CommSoil decompaction No Yes Yes Natural soundscapes improved/restored No Yes Yes Additional fencing for root protection No Common to all action alternatives Comm

Visitor Use and Access

Improved visitor orientation and wayfinding No Common to all action alternatives CommImproved ecological, historical and cultural interpretation No Common to all action alternatives CommPrimary visitor contact At lower Grove staging area At South Entrance Hub At GriVisitor amenities Gift Shop (snacks) at lower Grove area,

Museum (interpretation, books) in upper

Grove area

New/relocated visitor information and

services at South Entrance Hub, includinginformation, educational and other salesitems

New /r

service

Mariposa Grove Museum interpretive components Contains primary interpretative exhibits for

the Grove.

Primary interpretive information relocated

to South Entrance Hub. Repurpose museum

to ensure protection of historic resource.

Primar

to Grizensure 

Wawona Point overlook Access for utility functions only. Common to all action alternatives: Repair

historic walls and overlook.

Comm

histori

Visitor winter access to Grove (all­season visitor enjoyment ) Road closed, not plowed. Can ski/snowshoe

from South Entrance, limited parking (20spaces) at South Entrance.

Could ski/snowshoe, hike from South

Entrance if road/gate closed, ample parkingat South Entrance. 50­80 seasonal spacesavailable at the picnic area and lower Groveif road open.

Could 

trailhe

Giant 

parkin

Accessible trail No

Paths of travel in lower Grove area not up

to accessibility standards.

Lower Grove area, Grizzly Giant with

potential accessible trail expansions in those

areas

Lower 

Trail from South Entrance to the Grove None Utilize abandoned Washburn Road as trail

to picnic area and continue into lower

Grove area.

None 

Accessible road access(for private vehicles with placards) Access to lower Grove area, Grizzly Giant,

and upper Grove area loop road.

Access to lower Grove area and Grizzly

Giant.

Access 

Giant.

Accessible parking spaces 2 at lower Grove area 8 at South Entrance; 6 at lower Grove area ;

3 at picnic area; 8 at Grizzly Giant

7 at G

Accessibility of visitor amenities Accessible vault toilet at picnic area along

Mariposa Grove Road (outside Grove).Accessible vault toilet in lower Grove area.

Accessible comfort stations at South

Entrance and lower Grove. Accessible vaulttoilets at Grizzly Giant and picnic area.

Access

Grove

Transportation

Commercial tram staging area and operations (approximate)

(Tram is accessible.)

Yes, through upper Grove loop road,

staging at lower Grove area

No service No ser

Shuttle access to lower Grove area (Shuttle is accessible.) Yes, peak season (Memorial Day­Labor Day) Yes, expanded to include shoulder seasons

(April through October as weather permits)

N/A 

Shuttle schedule (approximate) May – October, South Entrance and

Wawona to lower Grove area

April – October, South Entrance to lower

Grove area; occasional service betweenSouth Entrance and Wawona

No ser

Standard vehicle parking spaces 20 at South Entrance, 115 seasonal at lower

Grove area. Over 100 spaces at Wawona areused for overflow parking.

248 at South Entrance, 25­50 seasonal at

lower Grove area, 25­50 seasonal at picnicarea

20 sea

Grizzly 

Final Environmental Impact Statement 

Proposed Project Action/Component Alternative 1: No­Action

Alternative 2: South Entrance Hub 

(Preferred Alternative) A

Large vehicle parking spaces <5 30 oversize, 9 commercial bus/shuttle at

South Entrance

27­32 

Tour bus access Buses less than 40 feet long can park and

drop passengers in lower Grove area. Buses

greater than 40 feet park at Wawona and

transfer passengers to park shuttles.

Buses greater than 40 feet long would stop

at South Entrance for transfer to shuttle.Depending on facility capacity and shuttleoperations, buses less than 40 feet long maydrop off passengers in lower Grove area and

park at South Entrance.

All bu

Infrastructure Improvements

Retain Mariposa Grove Road surface within the Grove Paved to Wawona Point Paved to Grizzly Giant Paved Conversion of Mariposa Grove Road to hardened trail No Yes, from Grizzly Giant to Wawona Point

(10­12’wide)

Yes, fr

(10­12

Water pipe repair or replacement No Yes Yes Water tank and chlorination unit Present location along upper Grove loop

road

Relocate near museum Reloca

Comfort station fixtures (flush or vault) 10 at South Entrance, 1 at picnic area, 8 at

lower Grove area, 1 at Grizzly Giant, 1 and

10 at upper Grove area

28 at South Entrance, 1 at picnic area, 10 at

lower Grove area, 1 at Grizzly Giant (shuttledrop off), 10 at upper Grove

10 at S

lower upper 

Infrastructure Relocation/Realignment

Parking hub Lower Grove area South Entrance Grizzly New roads None Lower Grove bypass road (0.10 mile) New r

Giant 

New vehicular bridges None Optional bridge at Three Sentinels pending

further study

Two in 

Septic tank/leach field installation and/or improvement No New system at South Entrance and lower

Grove areas (if feasible), replace system inupper Grove area

Replac

Mariposa Grove shuttle drop­off areas Wawona, South Entrance, and lower Grove

area

South Entrance and lower Grove area None 

Bus parking pads (for heavy vehicle parking loads) No Yes, South Entrance and lower Grove area Yes, GSouth Entrance intersection Existing T Roundabout if T­intersection exceeds

capacity

Existin

Sustainability

Infrastructure consolidation No Yes Yes Improved traffic flow and orientation No Yes Yes Improvements to energy­ and water­efficient design No Yes Yes, m

Final Environmental Impact Statement 

Table 2­3 – Summ

Surfaces / Ground Disturbance Alternative 1: No Action Alternative 2: South Entrance Hub Alte

Existing Conditions

Existing impervious (asphalt)surface in lower Grove area 2.9 acres N/A N/A Existing impervious (asphalt) surface at South Entrance

parking lot

0.31 acre N/A N/A 

Existing impervious(asphalt) surface at Wawona Point Yes, at overlook N/A N/A Existing road through the Grove 8.4 acres N/A N/A Existing trails within the Grove 3.5 acres minimum (based on estimated

widths)

N/A N/A 

Ecological Restoration

Net change in development, excluding areas needed for

new leach fields

N/A 0.74 acre addition of developed area projectwide (comprised of 3.98 acre net reduction of

developed area within the Grove, plus 4.72

acre new development at the South Entrance)

0.5 acre ad

wide (comdeveloped 

acre new d

arrival area 

Restoration of giant sequoia habitat through reduction of

impervious surfaces in lower Grove

N/A 1.44 acres restoration of giant sequoia habitat

(1.45 acre of new build out, all except

0.32 acre atop previous impervious footprint.)Removal of 1.44 acres of the existing

development footprint within the lower

Grove area would comprise a 50% reduction

of impervious surfaces (includes footprint of

accessible trails)

2.38 acres 

(0.52 acre oimpervious 

of the existthe lower G

reduction o

Net restorable area due to trail removal N/A 0.43 acre 0.58 acre Restoration of giant sequoia habitat resulting from

narrowing of Mariposa Grove Road or conversion of road

segments to trails

N/A Removal of 2.11 acres of the existing paved

road throughout the Grove comprises a 25%

reduction of road

Removal o

road throu

reduction o

Restoration of hydrologic connectivity to areas where

natural flow is disrupted

N/A Restore two areas where water is currently

diverted from its natural course within the

Grove (areas are 21.1 acres and 27.5 acres).Restore flow in one area where water is being

diverted from the Grove altogether (88.5

acres)

Same as Al

Giant sequoia habitat restoration area within the Grove N/A 3.99 acres removal of built footprint within

Grove (27% reduction)

5.75 acres 

Grove (39% 

Restore of natural hydrologic process by repairing leaking

water pipe in upper Grove area

N/A Restore natural hydrologic condition within

the western end of the upper Grove Palustrine

Emergent wetland by analyzing 4000 lineal

feet of water pipe that is understood to be

leaking and contributing chlorinated water to

the wetland

Same as Al

Wetland restoration N/A 1.0 acre total of wetland restoration due to

ecological restoration activities in the lower

Grove area and removal of trails and road

narrowing in the upper Grove area

Same as Al

Construction Footprint

Trail from South Entrance to picnic area using existing

Washburn Road to picnic area and construction of a new

trail extending from picnic area to lower Grove

N/A 0.66 acre (includes 0.42 acre along old road

alignment through non­giant sequoia forest;

0.21 acre new trail through non­giant sequoia

forest; and 0.03 acre new trail through giantsequoia forest)

N/A 

Area required for South Entrance construction N/A 5.0 to 6.0 acres +/­ of non­giant sequoia forest N/A South Entrance build out (i.e. net footprint after

construction)

N/A 4.72 acres of non­giant sequoia forest (3.13

acres of impervious surfaces)

N/A 

Clearing area required for Grizzly Giant Hub construction N/A N/A 5.61 acres 

shrubland

Final Environmental Impact Statement 

Surfaces / Ground Disturbance Alternative 1: No Action Alternative 2: South Entrance Hub Alte

Grizzly Giant area build out (net new footprint after

construction)

N/A 0.06 acre of non­giant sequoia forest (includes

0 acres impervious surfaces)

3.13 acres 

(includes 2

New bypass road build out footprint under Alternative 3 N/A N/A 2.20 acres, 

sequoia fo

giant sequcrossings o

Prime Habitat Considerations

Disturbance to prime denning pacific fisher habitat 0 acres 0 acres 3.11 acres Traffic impacts through fisher habitat Current activity in habitat areas Decreases overall traffic Increases o

Potential Impacts to Trees

Giant Sequoia seedlings/saplings potentially removed or

transplanted (0­15" DBH) 1

N/A 30 (+5 at least seedlings) 0 

Juvenile Giant Sequoia trees potentially removed(15­30"

DBH) 1

N/A 5 0 

Giant Sequoia Trees potentially removed (30"or greater

DBH) 1

N/A 0 0 

Non­Giant Sequoia habitat potentially removed (area in

acres)

N/A 4.0 – 5.0 acres 6.9 acres

(Includes b

Grizzly Gia

Non­Giant Sequoia trees potentially removed (Total

comprised of cedar, pine, fir, and oak 2

N/A 414 trees 591 trees (

noted belo

• By Size:Non­Giant Sequoia trees potentially

removed (10­15” DBH)

N/A 17 trees 189 trees (

parking lot 

Grizzly Gia

accessible d

• By Size: Non­Giant Sequoia trees potentially

removed

(15­30” DBH)

N/A 281 trees 291 trees (

parking lot 

Grizzly Gia

accessible d

• By Size: Non­Giant Sequoia trees potentially

removed (30+” DBH)

N/A 116 trees 111 trees (

parking lot 

Grizzly Gia

accessible d

• By Species: Cedar trees potentially removed N/A 161 59 • By Species: Pine trees potentially removed N/A 109 135 • By Species: Fir trees potentially removed N/A 138 394 • By Species: Oak trees potentially removed N/A 6 3 

Non­Giant Sequoia tree habitat potentially impacted by

construction of new trail from South Entrance to the lower

Grove area using Washburn Road alignment

N/A 0.67 acres (includes 0.42 acres along old road

alignment through non­giant sequoia forest;

0.21 acres new trail through non­giantsequoia forest; 0.03 acres new trail throughgiant sequoia forest)

N/A 

1 Giant sequoia tree impacts would be due to the proposed re­route of Mariposa Grove Road through the lower Grove area under Alternatives 2 and 4. The potential tree 

specific locations have not been surveyed yet. During the design of the re­route, impacts on giant sequoia trees would be avoided as much as possible.

2 Tree Impact Measurement Constraints: (1) Trees below 10” diameter at breast height (DBH) were not surveyed at South Entrance. (2) Tree density and composition was es

composition in non­giant sequoia surveyed areas. (3) Tree density and composition was estimated for west Grizzly Giant parking area (Alternative 3) based on average co

Final Environmental Impact Statement