Analysis Topics: Natural Resources 

Lightscapes 

Merced Wild and Scenic River Comprehensive Management Plan / DEIS 9-635 

Lightscapes 

Affected Environment 

Scope of the Analysis 

The National Park Service (NPS) defines lightscapes as “natural resources and values that exist in the 

absence of human-caused light” (NPS 2006). This section addresses the lightscape environment across 

the Merced River and South Fork Merced River corridors within Yosemite National Park. Particular 

attention is paid to existing sources of artificial lighting and their implications for the lightscape 

environment. River segments with similar types of developments and sources of lighting are discussed 

together. 

Regulatory Framework 

NPS Management Policies 2006 

The NPS Management Policies 2006 set forth specific measures overseen by the park superintendent 

for the preservation of natural lightscapes in an effort to “minimize light that emanates from park 

facilities, and also seek the cooperation of park visitors, neighbors, and local government agencies to 

prevent or minimize the intrusion of artificial light into the night scene of the ecosystems of parks” 

(NPS 2006). These policies commit the NPS to protecting natural darkness and other components of 

natural lightscape within parks. To achieve the dual goal of providing for visitor safety and 

management of natural lightscapes, section 4.10 of the NPS management policies direct the park to: 

 Restrict the use of artificial lighting in parks to those areas where security, basic human safety, 

and specific cultural resource requirements must be met. 

 Use minimal-impact lighting techniques. 

 Shield the use of artificial lighting where necessary to prevent the disruption of the night sky, 

natural cave processes, physiological processes of living organisms, and similar natural 

processes (NPS 2011c). 

Overview 

The national park system includes some of the few places where views of the night sky remain in-tact 

and relatively unimpeded by the glare of urban night lighting. The enjoyment and appreciation of these 

natural lightscapes depend on many factors, including the weather, the clarity of the air, and the 

amount of light pollution present. Light pollution is of particular concern in national parks; nearly 

every park in the national park system is affected by some level of artificial light in the night sky 

(DURISCOE 2005). Nationwide, the glare and “sky glow” from urban areas are encroaching on dark 

skies in areas normally considered remote, including within the Sierra Nevada region. 

The NPS considers natural lightscapes as an intrinsic natural and cultural value of all parks; therefore, 

the protection of lightscapes has been added to the responsibilities of park managers. While natural 
AFFECTED ENVIRONMENT AND ENVIRONMENTAL CONSEQUENCES

9-636 Merced Wild and Scenic River Comprehensive Management Plan / DEIS

lightscapes are recognized as a critical component of ecological processes, the night sky is also 

considered a critical part of cultural heritage in national parks and, in at least one case, the night sky 

has been designated by a state legislature as an endangered historic resource (Rogers and Sovic 2001). 

In addition, night sky visibility is an important aesthetic component of wilderness values. 

Measuring Dark Night Skies in Yosemite National Park 

In 2001, a model developed jointly by the NPS and the National Oceanic and Atmospheric 

Administration was used to evaluate the effects of light pollution on areas administered by the NPS for 

the purpose of protecting night sky visibility. This was a nationwide model that built upon previous 

efforts to distinguish the effects of artificial sky glow from cities and naturally occurring sky glow 

(e.g., moonlight). The results were calibrated by comparing the expected amount of light pollution for 

various locations with actual observations. According to the results of this model, about two-thirds of 

Yosemite National Park is at or near pristine conditions for dark night skies, while in the remaining 

one-third of the park, primarily the western portion, light pollution is affecting night sky quality 

(Albers and Duriscoe 2001). 

The model was not calibrated to a level that would distinguish among segments of the Merced River 

corridor, but generally this would equate to near pristine conditions for the upper reaches of the 

river’s main stem and the South Fork Merced River (i.e., Segments 1 and 5), with potential night-sky 

impacts detectable along the lower reaches (i.e., Segments 2, 3, 4, and 7 downstream). More localized 

data collection would be necessary to confirm the model’s implications for the study area. 

To effectively manage night skies as a resource in parks, the NPS Night Sky Team was formed in 2000 

to measure and inventory night skies in parks across the nation. The Night Sky Team has developed a 

system for measuring sky brightness to quantify the source and severity of light pollution. This system, 

developed with assistance from professional astronomers and the International Dark-Sky Association, 

utilizes a research-grade digital camera to capture the entire sky with a series of images. Since the 

development of this system, inventories of night sky quality have been conducted at several parks; 

these night sky baseline assessments are intended to form the foundation for a monitoring program to 

detect long-term changes in the parks’ lightscape environments. 

In August and September 2005, the Night Sky Team took sky quality measurements in the park from 

Sentinel Dome, located west of Glacier Point on the rim of Yosemite Valley, and Pothole Dome, on the 

west end of Tuolumne Meadows. The results of visual observation and measurements indicate that 

artificial light seen from Sentinel Dome is significantly brighter than Pothole Dome. The Night Sky 

Team assessment indicated that sources of light pollution at both Sentinel Dome and Pothole Dome 

include Fresno, the Modesto/Stockton/Sacramento area, and the Reno/Carson City area. However, 

overall, the darkest park of the sky as viewed from Pothole Dome was observed to be “very dark,” with 

near pristine conditions, while the darkest part of the sky at Sentinel Dome was 0.2–0.3 orders of 

magnitude brighter (DURISCOE 2005). 
Analysis Topics: Natural Resources 

Lightscapes 

Merced Wild and Scenic River Comprehensive Management Plan / DEIS 9-637 

Lighting Guidelines 

While the majority of light pollution seen in national parks radiates from population centers outside 

park boundaries, the NPS recognizes that artificial lighting within parks may have a detrimental effect 

on natural lightscapes, as well. Yosemite National Park has worked with the park concessioner to 

develop, refine, and implement lighting guidelines for the park. These guidelines are intended to 

balance the safety and security of employees and visitors, universal accessibility, and the scientific and 

aesthetic importance of the natural lightscape that NPS is obligated to protect. 

The focus of the current parkwide lighting guidelines includes Yosemite Valley and other heavily used 

portions of the park; there are no lighting guidelines specific to the Merced Wild and Scenic River 

corridor. These guidelines divide the park into nonwilderness areas, where visitor services are 

concentrated, and wilderness areas, which are managed and maintained as natural areas and visitors 

have to assume a certain degree of risk and responsibility for their own safety. 

Nonwilderness areas, such as Yosemite Valley, El Portal, and Wawona, are lighted for safety, security, 

and accessibility in accordance with the following NPS principles: warrant light only where needed, 

control light only when needed, shield direct light downward, manage the light spectrum by selecting a 

lamp color that minimizes negative impacts, manage light intensity by using the minimum amount of 

light necessary, and ensure light efficiency by selecting the most energy efficacious lamp and fixture. In 

addition to these principles, the lighting guidelines apply effective use of good design in areas of 

development to minimize or eliminate light clutter. 

In some wilderness areas, electric lighting may be used but only as determined necessary on a case-bycase basis by the NPS. Where artificial lighting is present, lighting guidelines are intended to prevent both 

light pollution and light trespass, primarily using structural means to control light and cast light 

downward, as noted in the light principles above. As a secondary measure, power limits (in the form of 

low lamp wattage) are set on all lamp types to minimize inadvertent light trespass or pollution. By 

applying these measures, light pollution, energy waste, and diminished visitor experience stemming from 

undesired light spillover would be prevented through proper NPS lightscape management (NPS 2011c). 

The Lightscape Environment within the Merced River Corridor 

Segments 1, 5, and 8: Merced River Above Nevada Fall, and South Fork Merced River Above and 

Below Wawona 

Lightscapes in designated wilderness areas are dominated by natural sources of light and dark night 

skies. Within Segment 1, artificial lighting would be concentrated around the Little Yosemite Valley, 

Merced Lake Backpackers, and Moraine Dome campgrounds, as well the 60-unit Merced Lake High 

Sierra Camp. Campground lighting would generally include hand-held torches, lanterns, and campfires. 

Lighting sources around the Merced Lake High Sierra Camp would be similar to that of the 

campgrounds, with the additional glow of the camp’s interior operational lighting. Similarly, hand-held 

torches, lanterns, and campfires tend to be the main sources of lighting in Segments 5 and 8, with the 

occasional flash of a vehicle headlight from a road or turnout within an adjacent nonwilderness area. 
AFFECTED ENVIRONMENT AND ENVIRONMENTAL CONSEQUENCES

9-638 Merced Wild and Scenic River Comprehensive Management Plan / DEIS

Segment 3 and 6: Merced River Gorge and Wawona Impoundment 

In the Merced River Gorge and Wawona Impoundment areas (i.e., Segments 3 and 6), lightscapes are 

defined largely by natural sources and dark night skies. The main source of artificial night lighting 

within the gorge segment is from automobile headlights along Highway 140, and from the adjacent 

developed areas of El Portal and Yosemite Valley. At the impoundment, the only potentially detectable 

sources of night lighting are that of the community of Wawona and nearby Camp Wawona, described 

below, which are more than 0.5 mile away. 

Segments 2, 4, and 7: Yosemite Valley, El Portal, and Wawona 

Yosemite Valley, El Portal, and Wawona host the greatest concentrations of development within the 

park, and thus the greatest amount of artificial night lighting. Sources of light pollution within these 

areas include utility lamps, shaded pathway lights, spot and other exterior lights, illuminated signs, 

decorative architectural lights, the glow of interior lights, fluorescent service station signs, automobile 

headlights, and campfires. Within Segments 2, 4, and 7, lighting is most intense in existing developed 

areas. For example, within Segment 2, nighttime lighting is most visible within the housing and lodging 

areas of Curry Village, The Ahwahnee, and the Yosemite Lodge complex. Lighting within lesser 

developed areas, such as Housekeeping Camp and East Valley campgrounds, is also considerable, but 

less pronounced than in the aforementioned areas (NPS 2010e). More specific information about the 

facilities and infrastructure with which such lighting is associated include administrative and housing 

developments described in the “Park Operations and Facilities” section; the lodging units, 

campgrounds, and associated infrastructure described in the “Visitor Experience/Recreation” section; 

and the parking lots and vehicles on roadways described in the “Transportation” section. 

Environmental Consequences Methodology 

The lightscapes impact assessment evaluates how the plan would affect the dark night skies in the 

Merced River corridor. Impacts were evaluated in terms of their context, intensity, and duration, and 

whether the impacts were considered beneficial or adverse. 

 Context. The context of the impact considers whether the impact would be local or regional. 

For the purposes of this analysis, local impacts would be those that occur within Yosemite 

National Park or impacts specific to the Merced River corridor. In considering lightscape 

impacts, it is assumed that impacts would be consistently local. 

 Intensity. The intensity of the impact considers whether the impact would be negligible, 

minor, moderate, or major. Negligible impacts would be considered not detectable, with no 

discernible effect on the ambient lightscape environment. Minor impacts would be slightly 

detectable but not expected to have an overall effect on conditions. Moderate impacts would 

be clearly detectable and could have an appreciable effect. Major impacts would have a 

substantial, highly noticeable influence on the ambient lightscape environment. 

 Duration. The duration of the impact considers whether the impact would occur in the short 

term or the long term. A short-term impact would be temporary in duration or transitory in 

effect, such as light from passing vehicles. A long-term impact would have a permanent effect 

on the ambient lightscape environment. 
Analysis Topics: Natural Resources 

Lightscapes 

Merced Wild and Scenic River Comprehensive Management Plan / DEIS 9-639 

 Type of Impact. Impacts are evaluated in terms of whether they would be beneficial or 

adverse to the ambient lightscape environment. Beneficial impacts would reduce associated 

levels of light, while adverse impacts would have the opposite effect. 

Environmental Consequences of Alternative 1 (No Action) 

The lightscapes impact assessment involves the identification and qualitative description of the types 

and characteristics of actions proposed under each alternative that could affect the lightscape 

environment and dark night skies of the Merced River and South Fork Merced River corridors. The 

examination of effects is limited to sources of light within the park, focused on the location of facilities 

and operational features that produce light. 

Although sky glow radiating from population centers on either side of the Sierra Nevada affects dark 

night skies in the river corridor, the plan alternatives would have no effect on the regional sources of 

this impact; therefore, this is not addressed as part of the environmental consequences of the plan. As 

stated under “Affected Environment,” above, sky glow is more evident in the lower reaches of the river 

corridor, closer to the major population centers in California. Growth in the region would be expected 

to increase this adverse effect on lightscapes in the river corridor. 

The lightscapes impact assessment evaluates how changes resulting from the plan’s management 

measures would affect the dark night skies in the corridor. Impacts are evaluated in terms of their 

context, intensity, and duration, and whether the impacts would be beneficial or adverse. Alternative 1 

(No Action) assumes the continuation of lightscape management under NPS Management Policies 2006

and other existing policies that could influence lighting decisions. In addition, the park recently 

completed parkwide lighting guidelines, as described in the “Lighting Guidelines” subsection above, 

and is presently working with the park concessioner on their implementation. While new sources of 

lighting or modifications to existing sources could occur under Alternative 1 (No Action), none is 

proposed. However, through continued implementation of the Lighting Guidelines, NPS will improve 

the park’s dark night skies. Lightscapes within the corridor are and will continue to be influenced by 

the level of development within each river segment. As such, the following paragraphs analyze the 

implications of Alternative 1 on groups of segments with similar development and sources of lighting. 

Segments 1, 5, and 8: Merced River Above Nevada Fall, and South Fork Merced River Above 

and Below Wawona 

Lightscapes in designated wilderness areas (i.e., Segments 1, 5, and 8) would continue to be dominated 

by natural sources of light and dark night skies. Sources of night lighting within Segments 1, 5, and 8 

would continue to include campfires and occasional vehicle headlights from adjacent, nonwilderness 

areas (primarily within the South Fork Merced River segments). Artificial lighting associated with 

operation of the Merced Lake High Sierra Camp and nearby wilderness campgrounds would also 

continue to affect the lightscape within Segment 1. There are no actions proposed under Alternative 1 

that would explicitly affect lighting within Segments 1, 5, and 8. Overnight visitation within these 

wilderness areas would be expected to remain similar to that of present conditions. As a result, the 

long-term impacts of Alternative 1 on the lightscape environment within Segments 1, 5, and 8 would be 

local, negligible to minor, and adverse. 
AFFECTED ENVIRONMENT AND ENVIRONMENTAL CONSEQUENCES

9-640 Merced Wild and Scenic River Comprehensive Management Plan / DEIS

Segments 3 and 6: Merced River Gorge and Wawona Impoundment 

In the Merced River gorge and Wawona Impoundment areas (i.e., Segments 3 and 6), lightscapes 

would continue to be defined by natural sources and dark night skies. The main source of artificial 

night lighting within the gorge would continue to be automobile headlights on Highway 140. At the 

impoundment, the potentially detectable sources of night lighting would continue to originate within 

Wawona and nearby Camp Wawona. Increased visitation could result in a relatively minor increase in 

transient night lighting from greater numbers of cars traveling through Segment 3, or from exterior 

safety lighting in Wawona, adjacent to Segment 6. However, nighttime visitation or development 

within these areas would not be expected to increase substantially with time. As a result, Alternative 1 

would have a local, long-term, negligible, adverse effect on the lightscape environment within 

Segments 3 and 6.

Segments 2, 4, and 7: Yosemite Valley, El Portal, and Wawona 

Yosemite Valley, El Portal, and Wawona (i.e., Segments 2, 4, and 7) would continue to host the greatest 

concentration of development within the park, and thus the greatest amount of artificial night lighting. 

Sources of night lighting within these areas would continue to include utility lamps, bus stations, 

shaded pathway lights, spot and other exterior lights, illuminated signs, decorative architectural lights, 

the glow of interior lights, fluorescent service station signs, automobile headlights, and campfires. 

Within Segments 2, 4, and 7, such lighting would continue to be most intense around those existing 

developed areas, as described under “Affected Environment” above, including administrative and 

housing facilities, lodging and campground operations, and parking lots and roadways. No new 

substantial sources of night lighting are anticipated under Alternative 1. However, with increased 

visitation, potential sources of additional lighting within the park could include those associated with 

increased nighttime traffic and greater numbers of overnight campground visitors during nonpeak 

seasons. The long-term implications for the park’s lightscape environment in Segments 2, 4, and 7 

would be local, negligible to minor, and adverse. 

Summary of Alternative 1 (No Action) Impacts 

Lightscapes in designated wilderness areas (i.e., Segments 1, 5, and 8) would not be expected to change 

over time under Alternative 1 (No Action). In-park sources of light pollution, including occasional 

campfires, vehicle headlights, and artificial lighting in Little Yosemite Valley and Merced Lake High 

Sierra Camp, would remain in these wilderness areas. In the areas between the wilderness and more 

developed areas (i.e., Segments 3 and 6), lightscapes would continue to be characterized by near 

pristine conditions, similar to wilderness areas, but with occasional intrusion of night lighting from 

passing vehicles or nearby developments. In the more developed areas of the corridor (i.e., segments 2, 

4, and 7), lightscapes would continue to be shaped by local artificial lighting along roads, housing and 

administrative facilities, and visitor service areas. The continuation of present visitation trends, and the 

associated increased nighttime traffic and overnight campground visitors during nonpeak seasons 

could result in an increase in parkwide night lighting, especially in areas of existing development. As a 

result, implementation of Alternative 1 could have local, long-term, negligible to minor, adverse 

impacts on lightscapes within the nonwilderness segments of the Merced River and South Fork 

Merced River corridors. 
Analysis Topics: Natural Resources 

Lightscapes – Actions Common to Alternatives 2–6 

Merced Wild and Scenic River Comprehensive Management Plan / DEIS 9-641 

Environmental Consequences of Actions Common to Alternatives 2–6 

Segments 3 and 6: Merced River Gorge and Wawona Impoundment 

There are no actions proposed for Alternatives 2-6, or any individual alternative, that would impact 

the lightscape environment within Segments 3 and 6. As a result, these segments are not discussed 

further within this section. 

Segments 2, 4, and 7: Yosemite Valley, El Portal, and Wawona 

Impacts of Actions to Protect and Enhance River Values 

Under Alternatives 2–6, the park would remove from Segment 2 all campsites within the 100-year 

floodplain. The park would also remove campsite 208 sites at Upper Pines Campground. These actions 

would have a local, long-term, negligible, beneficial impact on park lightscapes as the sources of night 

lighting associated with these sites (e.g., campsite facilities, campfires, vehicle headlights, camping 

lanterns) would be removed or relocated away from the center of the Merced River corridor. 

The park would also remove from Segment 7 a total of seven campsites from the area around 

archeological site CA-MRP-168/329/H (A.E. Wood Campground). For the same reasons noted for 

Segment 2, these actions would have a local, long-term, negligible, beneficial impact on park lightscapes. 

Impacts of Actions to Manage User Capacity, Land Use, and Facilities 

Visitor use management and facilities actions that could affect Yosemite Valley lightscapes stem from 

changes to employee housing, camping, parking, and administrative facilities. The lightscape 

environment of the East Valley and The Ahwanhee would be affected through increased overnight 

visitation and associated vehicle headlights at new campsites west of Backpackers Campground (16) 

and east of Camp 4 (40), and an expanded parking area at The Ahwahnee. As shown in table 9-120, a 

net reduction in Curry Village housing, including the removal of temporary housing at Huff House 

and Boys Town, would substantially reduce sources of artificial lighting in these areas. 

Expanded parking at Curry Village could increase artificial lighting through overhead lighting and/or 

from the headlights of greater numbers of vehicles within the area after sunset. Removal of the Village 

Garage, Concessioner General Offices, and Arts and Activities Center would improve the valley’s 

lightscape environment, particularly in the vicinity of Yosemite Village. Within the Yosemite Lodge 

area, the construction of a new parking lot and expansion of campgrounds would increase nighttime 

lighting associated with these facilities. However, the lightscape environment in these areas would also 

be improved through elimination of housing at Highland Court and the 1,000s cabins, as well as the 

NPS Volunteer Office and post office. 

Under Alternatives 2–6, the park would also construct infill housing units within the Rancheria area of 

Segment 4. These structures would affect park lightscapes in the vicinity of El Portal Village. In 

Wawona, the park would develop new facilities to house roads, maintenance, and fire-fighting 

operations. These facilities would be constructed in the area of the existing Maintenance Yard and 

have an adverse impact on the lightscape environment in this area. 
AFFECTED ENVIRONMENT AND ENVIRONMENTAL CONSEQUENCES

9-642 Merced Wild and Scenic River Comprehensive Management Plan / DEIS

TABLE 9-120: ALTERNATIVES 2-6 – CONCESSIONER EMPLOYEE HOUSING

Residential Units 

Removed 

New Residential 

Units 

Total Change in 

Residential Units 

Curry Village 310 164 -146 

Yosemite Lodge 90 0 -90 

Total Yosemite Valley 400 164 -236 

Rancheria 0 12 12 

Total El Portal 0 12 12 

Removal of administrative and visitor-serving facilities, campsites, and temporary housing would 

eliminate from the corridor numerous sources of nighttime lighting, specifically those associated with 

residential and administrative structures, and to a lesser extent, campgrounds. These actions would 

result in a net reduction in nighttime lighting and a corresponding long-term, negligible to minor, 

beneficial impact on the Merced River corridor’s lightscape environment. Construction of new 

facilities would have a detrimental effect on park lightscapes, mainly in the areas of the Yosemite 

Lodge, El Portal, and the Wawona Maintenance Yard. However, because these areas are already 

somewhat developed, and any new or modified exterior lighting fixtures would be required to comply 

with the park’s lighting guidelines and nighttime construction restrictions — incorporated by 

reference herein as mitigation measures MM-LITE-1 and -2 (see Appendix C) — the impact of these 

actions in Segments 2, 4, and 7would be local, long-term, negligible to minor, and adverse. 

Summary of Impacts Common to Alternatives 2–6 

The removal of campsites, commercial visitor-serving facilities, and temporary employee housing 

would result in a beneficial impact on the lightscape environment, as these actions would remove 

human-caused sources of lighting from the Merced River corridor. The construction of new employee 

housing within Segments 2 and 4, and new administrative facilities in Segment 7, would introduce new 

sources of artificial lighting into these areas. However, due to the scale of these activities, and with 

mitigation measures implemented, the overall impact on park lightscapes would be local, negligible, 

and beneficial. 

Environmental Consequences of Alternative 2: Self-reliant Visitor Experiences and 

Extensive Floodplain Restoration 

Segment 1: Merced River Above Nevada Fall 

Impacts of Actions to Manage User Capacity, Land Use, and Facilities 

Visitation within Segment 1 would be reduced through a decrease in the Little Yosemite Valley 

trailhead quota (from 150 to 25). This could improve the lightscape environment within Segment 1 by 

limiting the number of overnight visitors to the area, thereby reducing potential sources of artificial 

night lighting associated with that type of use (e.g., campfires). In addition, removal of the Merced 

Lake High Sierra Camp would eliminate sources of nighttime lighting in the vicinity of the camp, 
Analysis Topics: Natural Resources 

Lightscapes – Alternative 2 

Merced Wild and Scenic River Comprehensive Management Plan / DEIS 9-643 

including those associated with operation of the camp, such as fixtures around common areas and the 

exterior glow of internal lighting. Modifications to existing campgrounds would result in a further 

reduction in overnight visitation within Segment 1. As with removal of the Merced Lake High Sierra 

Camp, such modifications would result in a corresponding decrease in sources of nighttime lighting 

within these areas of Segment 1. The associated impact on the lightscape environment of Segment 1 

would be local, long-term, minor, and beneficial. 

Segment 1 Impact Summary: Actions to Manage user capacity, land use, and facilities would have a 

local, long-term, minor, beneficial impact on the lightscape environment of Segment 1. 

Segments 2, 4, and 7: Yosemite Valley, El Portal, and Wawona 

Impacts of Actions to Protect and Enhance River Values 

Specific Alternative 2 restoration projects that would occur within Segment 2 and have the potential to 

affect the Merced River corridor’s lightscape environment include removal of portions of Northside 

Drive and Southside Drive. Road removal would have a beneficial impact on the park’s lightscape 

environment within the vicinity of Ahwahnee and Stoneman meadows, as associated vehicle headlight 

impacts would be eliminated. However, the rerouting of traffic onto other roads would increase the 

incidence of vehicle-related night lighting along existing roadways that already experience such 

impacts. In the short-term, local, negligible, adverse impacts in Segment 2 may result from increased 

nighttime lighting of these construction areas to ensure safety. The long-term net effect of these 

projects would be local, negligible, and beneficial. 

Impacts of Actions to Manage User Capacity, Land Use, and Facilities 

Actions to manage visitor use and facilities under Alternative 2, specifically those concerning vehicle 

access and the number of overnight accommodations, would contribute to a 26% reduction in 

overnight visitation within the Yosemite Valley. As discussed in the context of specific management 

actions below, this reduction would effect a decrease in valley-wide nighttime lighting through the 

corresponding reduction in vehicles, lighted parking lots and lodging units and facilities to serve afterhours and overnight park visitors. 

As shown in table 9-121, a substantial number of campsites would be relocated within Segment 2. 

These modifications would increase sources of nighttime lighting, such as campfires and vehicle 

lighting in some areas (i.e., Yosemite Lodge and Camp 4 areas), while decreasing it in others (i.e., 

Lower Pines, North Pines, Upper Pines, and Backpackers Campgrounds). Despite these adjustments, 

the total reduction in the number of campsites within Segment 2 would still be nominal and not have 

an appreciable effect on the lightscape environment within Segment 2. 

As discussed in Environmental Consequences of Actions Common to Alternatives 2–6, and shown in 

table 9-122 the lightscape environment within Segment 2 would benefit from a substantial reduction 

in housing at Curry Village and the Yosemite Lodge areas, and Tacoya Dorms, among others, by 

eliminating the exterior glow of interior lighting, the need for outdoor lighting, and reduced vehicle 

traffic. 
AFFECTED ENVIRONMENT AND ENVIRONMENTAL CONSEQUENCES

9-644 Merced Wild and Scenic River Comprehensive Management Plan / DEIS

TABLE 9-121: ALTERNATIVE 2 CAMPGROUND MODIFICATIONS

Location 

Campsites 

(Alternative 2) 

Campsites 

(Alternative 1) 

Change from 

Alternative 1 

Yosemite Lodge and Camp 4 Areas 174 35 139 

Former Upper & Lower River Campground Areas 0 0 0 

Boys Town and Upper Pines Campground Areas 216 240 -24 

Lower Pines Campground Area 44 76 -32 

North Pines and Backpackers Campgrounds and 

Curry Village Stables Areas 16 111 -95 

Eagle Creek and Yellow Pine Administrative 

Campgrounds 0 4 -4 

Yosemite Valley Totalsa 450 466 -16 

Wawona 67 99 -32 

Wawona Total 67 99 -32 

TABLE 9-122: ALTERNATIVE 2 CONCESSIONER EMPLOYEE HOUSING AND VISITOR LODGING

Location 

Total 

Residential 

Units under 

Alternative 2 

Change in 

Residential 

Units from 

Alternative 1 

Total Visitor 

Lodging Units 

under 

Alternative 2 

Change in 

Visitor Lodging 

Units from 

Alternative 1 

Yosemite Village 65 -366 0 0 

The Ahwahnee 42 -6 123 0 

Curry Village 387 -195 433 33 

Yosemite Lodge 0 -90 0 -245 

Housekeeping Camp 0 0 0 -266 

Total Yosemite Valleya 494 -657 556 -494 

Rancheria 116 9 n/a n/a 

El Portal Village 92 12 n/a n/a 

Abbieville/Trailer Village 410 405 n/a n/a 

Total El Portalb 618 426 n/a n/a 

a Totals include the 236 residential units that would be removed from the Curry Village and Yosemite Lodge areas of Segment 2 under 

actions common to Alternatives 2-6. 

b Totals include the 12 residential units that would be constructed in the El Portal Village area of Segment 4 under actions common to 

Alternatives 2-6. 

Construction of 78 new hard-sided cabins at Curry Village would increase sources of artificial lighting 

within the Boys Town area, but these impacts would be more than offset form the reduction in housing 

within this area. Removal of all lodging and facilities from Housekeeping Camp would further reduce 

artificial lighting within the valley, including the interior cabin lighting, vehicle headlights, and campfires 

associated with this operation. Conversion of the Yosemite Lodge to day use, despite the proposed 
Analysis Topics: Natural Resources 

Lightscapes – Alternative 2 

Merced Wild and Scenic River Comprehensive Management Plan / DEIS 9-645 

increase in camping and parking within this area, would also improve the natural lightscape environment 

through elimination of lighting associated with these structures and reduced overnight visitation. 

Some of this work, specifically in the vicinity of Housekeeping Camp, Curry Village, Yosemite Village, 

and Yosemite Lodge – where large numbers of structures would be removed – may require a shortterm increase in nighttime lighting of the construction areas to ensure safety. However, over the longterm, the impact on the Segment 2 lightscape environment would be local, major, and beneficial. 

Under Alternative 2, the park would construct new housing for 405 employees within the Abbieville 

area of Segment 4. This project would contribute to area lightscape impacts through an increase in 

exterior lighting, the glow of interior lighting, and increased vehicle traffic. However, any new or 

modified exterior lighting would be required to comply with the park’s lighting guidelines and 

nighttime construction restrictions, incorporated by reference herein as mitigation measures 

MM-LITE-1 and -2 (see Appendix C). With mitigation, the long-term impact on Segment 4 would be 

local, moderate, and adverse. Within Segment 7, the Wawona stables would be removed and 32 

campsites eliminated from the Wawona Campground. The corresponding reduction in overnight 

visitation within these areas would reduce lightscape impacts. The long-term impact on Segment 7 

would be local, negligible, and beneficial. 

Segments 2, 4, and 7 Impact Summary: Actions to manage user capacity, land use, and facilities 

would have local, long-term, beneficial impacts on the lightscape environment, ranging from minor to 

moderate in Segments 2 and 7, and moderate adverse in Segment 4. 

Summary of Impacts from Alternative 2: Self-reliant Visitor Experiences and Extensive 

Floodplain Restoration 

Lightscape impacts associated with Alternative 2 management measures would result mainly from 

changes in park visitation, facilities serving overnight visitors, and employee housing, and generally be 

limited to Segments 2 and 4. The collective effect of Alternative 2 management actions would cause 

overnight visitation within the park to decrease. Under Alternative 2, a considerable number of 

housing and lodging units, as well as visitor-serving facilities, would be removed from Yosemite Valley. 

The lightscape environment within El Portal would be further affected through the construction of a 

substantial amount of new employee housing. Nonetheless, overall, existing, and potential future 

sources of human-caused lighting would be expected to decrease under Alternative 2, resulting in an 

overall improvement of the park’s lightscape environment. For these reasons, the long-term impacts of 

Alternative 2 on the park’s lightscape environment would be local, minor to moderate, and beneficial. 

Cumulative Impacts from Alternative 2: Self-reliant Visitor Experiences and Extensive 

Floodplain Restoration 

Cumulative effects on the park’s lightscape environment discussed herein are based on analysis of past, 

present, and reasonably foreseeable future actions in the Merced and South Fork Merced River 

corridors, in combination with potential effects of actions common to Alternatives 2-6 and those 

specific to Alternative 2. The projects identified below include only those projects that could affect 
AFFECTED ENVIRONMENT AND ENVIRONMENTAL CONSEQUENCES

9-646 Merced Wild and Scenic River Comprehensive Management Plan / DEIS

park lightscapes within or in the vicinity of the Merced River corridor. Each project is described more 

fully in Appendix B. 

Past Actions 

The following is a list of cumulatively considerable past actions concerning park lightscapes: 

 Cascades Housing Removal reduced artificial lighting by eliminating five housing units. 

 Removal of housing units as a result of the 1997 flood reduced artificial lighting. 

 Curry Village Employee Housing: the construction of 217 new housing units at Curry Village 

for flood-displaced employees increased artificial lighting. 

 Closure of Curry Village units due to rockfall hazard reduced artificial lighting. 

 Construction of temporary housing at the Curry Village Huff House for 102 rockfall-displaced 

employees increased artificial lighting. 

 Construction of six temporary housing units at Yosemite Valley Lost Arrow complex for 

rockfall-displaced employees increased artificial lighting. 

 Construction of 12 temporary housing units at The Ahwahnee for rockfall-displaced 

employees increased artificial lighting. 

Present Actions 

The following is a list of cumulatively considerable present actions concerning park lightscapes: 

 Completion of the Mariposa County General Plan “Housing Element Update” may contribute 

to increased night lighting if it provides for additional development in the region. 

 Implementation of the Yosemite Lighting Guidelines would reduce the impacts of artificial 

night lighting. 

 Relocation of 40 park staff from offices in El Portal to Mariposa may reduce artificial lighting 

in El Portal. 

 Permanent removal of Curry Village units within the rockfall hazard zone (noted above) 

would permanently reduce artificial night lighting. 

 Development of a new Wahhoga Indian Cultural Center would increase artificial night lighting. 

Reasonably Foreseeable Future Actions 

The following is a list of cumulatively considerable, reasonably foreseeable future actions concerning 

park lightscapes: 

 Development of the new concessioner prospectus could increase or decrease artificial night 

lighting, depending upon its terms. 
Analysis Topics: Natural Resources 

Lightscapes – Alternative 2 

Merced Wild and Scenic River Comprehensive Management Plan / DEIS 9-647 

Overall Cumulative Impact 

There are no anticipated development projects outside of those described herein that would 

contribute to light pollution within the park. Past actions, specifically the construction of housing for 

employees previously residing in hazard prone areas within Yosemite Valley, have slightly increased 

the amount of artificial lighting within the park. Present actions may result in regional increases in 

night-sky impacts, and the introduction of a few new individual sources of lighting within the park, but 

a continued overall reduction in the impacts associated with in-park lighting. As a result, when 

combined with the impacts of past and present actions, including those originating from outside the 

park, the cumulative effect of actions common to Alternatives 2-6 and those specific to Alternative 2 

would be local, long-term, minor to moderate, and beneficial. 

Environmental Consequences of Alternative 3: Dispersed Visitor Experiences and 

Extensive Riverbank Restoration 

Segment 1: Merced River Above Nevada Fall 

Impacts of Actions to Manage User Capacity, Land Use, and Facilities 

Visitation within Segment 1 would be reduced through a decrease in the Little Yosemite Valley 

trailhead quota (from 150 to 75). This could improve the lightscape environment within Segment 1 by 

limiting the number of overnight visitors to the area, thereby reducing potential sources of artificial 

night lighting associated with that type of use (e.g., campfires). In addition, removal of the Merced 

Lake High Sierra Camp would eliminate sources of nighttime lighting in the vicinity of the camp, 

including those associated with operation of the camp, such as fixtures around common areas and the 

exterior glow of internal lighting,. Modifications to existing campgrounds would result in a further 

reduction in overnight visitation within Segment 1. As with removal of the Merced Lake High Sierra 

Camp, such modifications would result in a corresponding decrease in sources of nighttime lighting 

within these areas of Segment 1. The associated impact on the lightscape environment within Segment 

1 would be local, long-term, minor, and beneficial. 

Segment 1 Impact Summary: Actions to manage user capacity, land use, and facilities would have a 

local, long-term, minor, beneficial impact on the lightscape environment of Segment 1. 

Segments 2, 4, and 7: Yosemite Valley, El Portal, and Wawona 

Impacts of Actions to Protect and Enhance River Values 

Specific Alternative 3 restoration projects that would occur within Segment 2 and have the potential to 

affect the Merced River corridor’s lightscape environment include removal of portions of Northside 

Drive and Southside Drive. Road removal would have a beneficial impact on the park’s lightscape 

environment within the vicinity of Ahwahnee and Stoneman meadows, as associated vehicle headlight 

impacts would be eliminated. However, the rerouting of traffic onto other roads would increase the 

incidence of vehicle-related night lighting along existing roadways that already experience such 

impacts. In the short-term, local, negligible, adverse impacts in Segment 2 may occur from increased in 
AFFECTED ENVIRONMENT AND ENVIRONMENTAL CONSEQUENCES

9-648 Merced Wild and Scenic River Comprehensive Management Plan / DEIS

nighttime lighting of these construction areas, if necessary to ensure safety. However, the long-term 

net effect of these projects would be local, negligible, and beneficial. 

Impacts of Actions to Manage User Capacity, Land Use, and Facilities 

Actions to manage visitor use and facilities under Alternative 3, specifically those concerning vehicle 

access and number of overnight accommodations, would contribute to a 23% reduction in overnight 

visitation within Yosemite Valley. As discussed in the context of specific management actions below, 

this reduction would affect a decrease in valley-wide nighttime lighting through the corresponding 

reduction in vehicles, lighted parking lots, lodging units, and facilities to serve after-hours and 

overnight park visitors. 

As shown in table 9-123, a considerable number of campsites would be relocated within Segment 2. 

These modifications would increase sources of nighttime lighting, such as campfires and vehicle 

lighting in some areas (i.e., Camp 4 area), while decreasing it in others (i.e., Lower Pines, Upper Pines, 

North Pines, and Backpackers Campgrounds). Despite these adjustments, the total increase in the 

number of campsites within Segment 2 would still be nominal and not have an appreciable effect on 

the lightscape environment within Segment 2. 

TABLE 9-123: ALTERNATIVE 3 CAMPGROUND MODIFICATIONS

 Campsites 

(Alternative 3) 

Campsites 

(Alternative 1) 

Change from 

Alternative 1 

Yosemite Lodge and Camp 4 Areas 70 35 35 

Former Upper & Lower River Campground Areas 0 0 0 

Boys Town and Upper Pines Campground Areas 274 240 34 

Lower Pines Campground Area 61 76 -15 

North Pines and Backpackers Campgrounds and 

Curry Village Stables Areas 68 111 -43 

Eagle Creek and Yellow Pine Administrative 

Campgrounds 4 4 0 

Yosemite Valley Totalsa 477 466 11 

Wawona 72 99 -27 

Wawona Total 72 99 -27 

a Totals include the construction of 16 new sites near Backpackers Campground and 40 new sites near Camp 4 area under actions 

common to Alternatives 2-6. 

As discussed in Environmental Consequences of Actions Common to Alternatives 2–6, and shown in 

table 9-124, the lightscape environment within Segment 2 would benefit from a substantial reduction 

in housing at Curry Village and the Yosemite Lodge areas. The lightscape environment within 

Segment 2 would also benefit from the removal of a notable number of housing units from the 

Yosemite Village area, including the Lost Arrow Cabins, among others, by eliminating the exterior 

glow of interior lighting, the need for outdoor lighting, and reduced vehicle traffic. 
Analysis Topics: Natural Resources 

Lightscapes – Alternative 3 

Merced Wild and Scenic River Comprehensive Management Plan / DEIS 9-649 

TABLE 9-124: ALTERNATIVE 3 CONCESSIONER EMPLOYEE HOUSING AND VISITOR LODGING

Location 

Total Residential 

Units in 

Alternative 3 

Change in 

Residential Units 

from Alternative 1

Total Visitor 

Lodging Units in 

Alternative 3 

Change in Visitor 

Lodging Units 

from Alternative 1

Yosemite Village 340 -91 n/a n/a 

Ahwahnee hotel 42 -6 123 0 

Curry Village 436 -146 355 -45 

Yosemite Lodge 104 14 143 -102 

Housekeeping 

Camp n/a n/a 0 -266 

Total Yosemite 

Valleya 922 -229 621 -413 

Rancheria 126 19 n/a n/a 

El Portal Village 92 12 n/a n/a 

Abbieville 0 0 n/a n/a 

Total El Portalb 218 31 n/a n/a 

a Totals include the 236 residential units that would be removed from the Curry Village and Yosemite Lodge areas of Segment 2 under 

actions common to Alternatives 2-6. 

b Totals include the 12 residential units that would be constructed in the El Portal Village area of Segment 4 under actions common to 

Alternatives 2-6. 

Removal of all lodging and most facilities from Housekeeping Camp, and several guest units from 

Curry Village, would further reduce artificial lighting within the valley, including the interior cabin 

lighting, vehicle headlights, and campfires associated with this facility. With reduced operation of the 

Yosemite Lodge and new employee housing and parking in its vicinity, lighting impacts in this area of 

Segment 2 would remain similar to those of Alternative 1 (No Action). 

Some of this work, specifically in the vicinity of Housekeeping Camp, Yosemite Village, and Yosemite 

Lodge – where large numbers of structures would be removed and/or constructed – may require a shortterm increase in nighttime lighting of the construction areas to ensure safety. However, over the longterm, the impact on the Segment 2 lightscape environment would be local, moderate, and beneficial. 

Under Alternative 3, the park would construct new housing for 19 employees within the Rancheria 

area of Segment 4. This project would contribute to area lightscape impacts through an increase in 

exterior lighting, the glow of interior lighting, and increased vehicle traffic. However, any new or 

modified exterior lighting would be required to comply with the park’s lighting guidelines and 

nighttime construction restrictions, incorporated by reference herein as mitigation measures 

MM-LITE-1 and -2 (see Appendix C). With mitigation, the long-term impact on Segment 4 would be 

local, minor, and adverse. Within Segment 7, the Wawona stables would be removed and 27 campsites 

eliminated from the Wawona Campground. The corresponding reduction in overnight visitation 

within these areas would reduce lightscape impacts. The long-term impact on Segment 7 would be 

local, negligible, and beneficial. 
AFFECTED ENVIRONMENT AND ENVIRONMENTAL CONSEQUENCES

9-650 Merced Wild and Scenic River Comprehensive Management Plan / DEIS

Segments 2, 4, and 7 Impact Summary: Actions to manage user capacity, land use, and facilities 

would have local, long-term, beneficial impacts on the lightscape environment, ranging from minor to 

moderate in Segments 2 and 7, and minor adverse in Segment 4. 

Summary of Impacts from Alternative 3: Dispersed Visitor Experiences and Extensive 

Riverbank Restoration 

Lightscape impacts associated with Alternative 3 management measures would result mainly from 

changes in park visitation, facilities serving overnight visitors, and employee housing, and generally be 

limited to Segment 2. The collective effect of Alternative 3 management actions would cause overnight 

visitation within the park to decrease. A considerable number of lodging units would be removed from 

the valley under Alternative 3, while some new employee housing would be developed in relative 

proximity to existing developed areas of the valley and El Portal. As a result, it is expected that existing 

and potential future sources of human-caused lighting would decrease, resulting in an overall 

beneficial impact on the park’s lightscape environment. For these reasons, the long-term impact of 

Alternative 3 measures on the park’s lightscape environment would be local, minor to moderate, and 

beneficial. 

Cumulative Impacts from Alternative 3: Dispersed Visitor Experiences and Extensive 

Riverbank Restoration 

Overall Cumulative Impact from Alternative 3: Dispersed Visitor Experiences and Extensive 

Riverbank Restoration 

There are no anticipated development projects outside of those described herein that would 

contribute to light pollution within the park. As a result, when combined with the impacts of past and 

present actions, including those originating from outside the park, the cumulative effect of actions 

common to Alternatives 2-6 and those specific to Alternative 3 would be local, long-term, minor to 

moderate, and beneficial. 

Environmental Consequences of Alternative 4: Resource-based Visitor Experiences 

and Targeted Riverbank Restoration 

Segment 1: Merced River Above Nevada Fall 

Impacts of Actions to Manage User Capacity, Land Use, and Facilities 

Visitation within Segment 1 would be reduced through a decrease in the Little Yosemite Valley 

trailhead quota (from 150 to 100). This could improve the lightscape environment within Segment 1 by 

limiting the number of overnight visitors to the area, thereby reducing potential sources of artificial 

night lighting associated with that type of use (e.g., campfires). With designated camping only slightly 

reduced, and with retention of several campground facilities, sources of artificial lighting would 

remain concentrated within these areas of Segment 1. However, the removal and conversion of the 

Merced Lake High Sierra Camp would eliminate a considerable amount of nighttime lighting in the 

vicinity of the camp, specifically that associated with operation of the camp, such as fixtures around 
Analysis Topics: Natural Resources 

Lightscapes – Alternative 4 

Merced Wild and Scenic River Comprehensive Management Plan / DEIS 9-651 

common areas and the exterior glow of internal lighting. The resulting impact on the lightscape 

environment within Segment 1 would be local, long-term, minor, and beneficial. 

Segment 1 Impact Summary: Actions to manage user capacity, land use, and facilities would have a 

local, long-term, minor, beneficial impact on the lightscape environment of Segment 1. 

Segments 2, 4, and 7, Yosemite Valley, El Portal, and Wawona 

Impacts of Actions to Protect and Enhance River Values 

Specific Alternative 4 restoration projects that would occur within Segment 2 and have the potential to 

affect the Merced River corridor’s lightscape environment include removal of portions of Southside 

Drive and campsites from the 150-year floodplain. Road removal would have a beneficial impact on 

the park’s lightscape environment within the vicinity of Stoneman Meadow, as associated vehicle 

headlight impacts would be eliminated. However, the rerouting of traffic onto other roads would 

increase the incidence of vehicle-related night lighting along existing roadways that already experience 

such impacts. In the short-term, local, negligible, adverse impacts in Segment 2 may occur from 

increased nighttime lighting of road construction areas, if necessary to ensure safety. However, the 

long-term net effect of these projects would be local, negligible, and beneficial. 

Impacts of Actions to Manage User Capacity, Land Use, and Facilities 

Actions to manage visitor use and facilities under Alternative 4, specifically those concerning vehicle 

access and number of overnight accommodations, would contribute to a 7% increase in overnight 

visitation within Yosemite Valley. As discussed in the context of specific management actions below, 

this growth would cause an increase in valley-wide nighttime lighting through the corresponding 

increase in vehicles, lighted parking lots, lodging units, and facilities to serve after-hours and overnight 

park visitors. 

As shown in table 9-125, a substantial number of campsites would be added within Segment 2. These 

additions would increase sources of nighttime lighting, such as campfires and vehicle lighting in several 

areas, including the Former Upper and Lower River Campground areas, and Boys Town and Upper 

Pines Campground areas. This increase would offset lightscape benefits resulting from removal of 

campsites from Backpackers, Lower Pines, and North Pines campgrounds. The net effect of these 

changes to the lightscape environment within Segment 2 would be long-term, local, minor, and 

adverse. 

As discussed in Environmental Consequences of Actions Common to Alternatives 2–6, and shown in 

table 9-126, the lightscape environment within Segment 2 would benefit from a substantial reduction 

in housing at Curry Village and the Yosemite Lodge areas. The lightscape environment within 

Segment 2 would also benefit from the removal of a considerable amount of housing from the 

Yosemite Village area, including the Lost Arrow Cabins, among others, by eliminating the exterior 

glow of interior lighting, the need for outdoor lighting, and reduced vehicle traffic. However, some of 

the lightscape benefits of these actions would be offset by the construction of new housing in the 

vicinity of Yosemite Village. 
AFFECTED ENVIRONMENT AND ENVIRONMENTAL CONSEQUENCES

9-652 Merced Wild and Scenic River Comprehensive Management Plan / DEIS

TABLE 9-125: ALTERNATIVE 4 CAMPGROUND MODIFICATIONS

 Campsites 

(Alternative 4) 

Campsites 

(Alternative 1) 

Change from 

Alternative 1 

Yosemite Lodge and Camp 4 Areas 90 35 55 

Former Upper & Lower River Campground Areas 72 0 72 

Boys Town and Upper Pines Campground Areas 365 240 125 

Lower Pines Campground Area 61 76 -15 

North Pines and Backpackers Campgrounds and 

Curry Village Stables Areas 109 111 -2 

Eagle Creek and Yellow Pine Administrative 

Campgrounds 4 4 0 

Yosemite Valley Totalsa 701 466 235 

Wawona 69 99 -30 

Wawona Total 69 99 -30 

a Totals include the construction of 16 new sites near Backpackers Campground and 40 new sites near Camp 4 area under actions 

common to Alternatives 2-6. 

TABLE 9-126: ALTERNATIVE 4 CONCESSIONER EMPLOYEE HOUSING AND VISITOR LODGING

Total Residential 

Units in 

Alternative 4 

Change in 

Residential Units 

from Alternative 1 

Total Visitor 

Lodging Units in 

Alternative 4 

Change in Visitor 

Lodging Units 

from Alternative 1 

Yosemite Village 390 -41 0 0 

Ahwahnee hotel 42 -6 123 0 

Curry Village 387 -195 355 -45 

Yosemite Lodge 104 14 245 0 

Housekeeping 

Camp n/a n/a 100 -166 

Total Yosemite 

Valleya 923 -228 823 -211 

Rancheria 203 96 n/a n/a 

El Portal Village 92 12 n/a n/a 

Abbieville 0 0 n/a n/a 

Total El Portalb 295 108 n/a n/a 

a Totals include the 236 residential units that would be removed from the Curry Village and Yosemite Lodge areas of Segment 2 under 

actions common to Alternatives 2-6. 

b Totals include the 12 residential units that would be constructed in the El Portal Village area of Segment 4 under actions common to 

Alternatives 2-6. 

Removal of 166 lodging units and some facilities from Housekeeping Camp would eliminate a 

substantial amount of artificial lighting within the valley, including the interior cabin lighting, vehicle 

headlights, and campfires associated with this facility. Expanded parking at Camp 6 could increase 

artificial lighting through overhead lighting and/or from the headlights of greater numbers of vehicles 

departing the area after sunset. With continued operation of Yosemite Lodge and new campgrounds 
Analysis Topics: Natural Resources 

Lightscapes – Alternative 4 

Merced Wild and Scenic River Comprehensive Management Plan / DEIS 9-653 

and parking in its vicinity, lighting impacts in this area would also increase, mainly due to the increase 

in vehicles and camping-related nighttime activities. However, over the long-term, the impact of these 

actions on Segment 2 lightscapes would be local, minor, and beneficial. 

Under Alternative 4, the park would construct new housing for 96 employees within the Rancheria 

area of Segment 4. This project would contribute to area lightscape impacts through an increase in 

exterior lighting, the glow of interior lighting, and increased vehicle traffic. However, any new or 

modified exterior lighting would be required to comply with the park’s lighting guidelines and 

nighttime construction restrictions, incorporated by reference herein as mitigation measures 

MM-LITE-1 and -2 (see Appendix C). With mitigation, the long-term impact on Segment 4 would be 

local, minor to moderate, and adverse. Within Segment 7, the Wawona stables would be removed and 

27 campsites eliminated from the Wawona Campground. The corresponding reduction in overnight 

visitation within these areas would reduce lightscape impacts. The long-term impact on Segment 7 

would be local, negligible, and beneficial. 

Segments 2, 4, and 7 Impact Summary: Actions to manage user capacity, land use, and facilities 

would have local, long-term, beneficial impacts on the lightscape environment, ranging from negligible 

to minor in Segments 2 and 7, and adverse impacts ranging from minor to moderate in Segment 4. 

Summary of Impacts from Alternative 4: Resource-based Visitor Experiences and Targeted 

Riverbank Restoration 

Lightscape impacts associated with Alternative 4 management measures would result mainly from 

changes in park visitation and facilities serving overnight visitors, and employee housing, and generally 

be limited to Segments 2 and 4. The collective effect of Alternative 4 management actions would cause 

overnight visitation within the park to increase slightly. However, because of the shift in type and 

location of overnight accommodations within the park (i.e., campgrounds near existing developed 

areas of the park), the impacts associated with that visitation are expected to be negligible. Under 

Alternative 4, a considerable number of additional lodging units would be removed from the park, 

while some new facilities would also be developed in relative proximity to existing developed areas of 

the valley. The lightscape environment within El Portal would be further affected by the construction 

of a considerable amount of new employee housing. Taken together, it is expected that existing and 

potential future sources of human-caused lighting throughout the Merced River corridor would 

remain similar to Alternative 1 or decrease slightly, resulting in an overall long-term, local, minor, 

beneficial impact on the park’s lightscape environment. 

Cumulative Impacts from Alternative 4: Resource-based Visitor Experiences and Targeted 

Riverbank Restoration 

Overall Cumulative Impact from Alternative 4: Resource-based Visitor Experiences and Targeted 

Riverbank Restoration 

There are no anticipated development projects outside of those described here that would contribute 

to light pollution within the park. As a result, when combined with the impacts of past, present, and 

reasonably foreseeable actions, including those originating from outside the park, the cumulative long-
AFFECTED ENVIRONMENT AND ENVIRONMENTAL CONSEQUENCES

9-654 Merced Wild and Scenic River Comprehensive Management Plan / DEIS

term effect of actions common to Alternatives 2-6 and those specific to Alternative 4 would be local 

minor, and beneficial. 

Environmental Consequences of Alternative 5: Enhanced Visitor Experiences and 

Essential Riverbank Restoration 

Segment 1: Merced River Above Nevada Fall 

Impacts of Actions to Manage User Capacity, Land Use, and Facilities 

Visitation within Segment 1 would not be expected to change appreciably under Alternative 5; 

wilderness access quotas would remain as under Alternative 1 and modifications to overnight 

accommodations would be nominal. As such, potential sources of artificial night lighting associated 

with overnight wilderness visitation would continue. Similarly, with designated camping unchanged, 

and with retention of several campground facilities, sources of artificial lighting (e.g., campfires) would 

remain concentrated within these areas of the Merced River corridor’s wilderness. Reduction in the 

number of units at the Merced Lake High Sierra Camp would reduce slightly the amount of artificial 

lighting in the vicinity of the camp, specifically that of interior cabin lighting fixtures. The resulting 

long-term impact on the lightscape environment within Segment 1 would be local, negligible, and 

beneficial. 

Segment 1 Impact Summary: Actions to Manage user capacity, land use, and facilities would have a 

long-term, negligible, beneficial impact on the lightscape environment of Segment 1. 

Segments 2, 4, and 7: Yosemite Valley, El Portal, and Wawona 

Impacts of Actions to Manage User Capacity, Land Use, and Facilities 

Actions to manage visitor use and facilities under Alternative 5, namely those concerning vehicle 

access and number of overnight accommodations, would contribute to an 16% increase in overnight 

visitation within Yosemite Valley. As discussed in the context of specific management actions below, 

this growth would result in an increase in valley-wide nighttime lighting through the corresponding 

shift in vehicle headlights, lighted parking lots, lighted lodging units, and other facilities to serve afterhours and overnight park visitors. 

As shown in table 9-127, a considerable number of campsites would be added within Segment 2 under 

Alternative 5. These additions would increase sources of nighttime lighting, such as campfires and 

vehicle lighting in several areas, including the Former Upper River, Upper Pines, and Eagle Creek 

Campground areas. This increase would offset lightscape benefits resulting from removal of campsites 

from Backpackers, Lower Pines, and North Pines campgrounds. The net effect of these changes to the 

lightscape environment within Segment 2 would be long-term, local, minor, and adverse. 
Analysis Topics: Natural Resources 

Lightscapes – Alternative 5 

Merced Wild and Scenic River Comprehensive Management Plan / DEIS 9-655 

TABLE 9-127: ALTERNATIVE 5 CAMPGROUND MODIFICATIONS

 Campsites 

(Alternative 5) 

Campsites 

(Alternative 1) 

Change from 

Alternative 1 

Yosemite Lodge and Camp 4 Areas 70 35 35 

Former Upper River Campground Area 30 0 30 

Boys Town and Upper Pines Campground Areas 325 240 85 

Lower Pines Campground Area 71 76 -5 

North Pines and Backpackers Campgrounds and 

Curry Village Stables Areas 98 111 -13 

Eagle Creek and Yellow Pine Administrative 

Campgrounds 46 4 42 

Yosemite Valley Totalsa 640 466 174 

Wawona 86 99 -13 

Wawona Total 86 99 -13 

a Totals include the construction of 16 new sites near Backpackers Campground and 40 new sites near Camp 4 area under actions 

common to Alternatives 2-6. 

As discussed in Environmental Consequences of Actions Common to Alternatives 2–6, and shown in 

table 9-128, the lightscape environment within Segment 2 would benefit from reductions in housing at 

Curry Village and the Yosemite Lodge areas. However, some of this benefit would be offset by the 

exterior glow of interior lighting, outdoor lighting, and continued vehicle traffic associated with the 

construction of new housing in the vicinity of Yosemite Village. 

TABLE 9-128: ALTERNATIVE 5 CONCESSIONER EMPLOYEE HOUSING AND VISITOR LODGING

Location 

Total Residential 

Units in 

Alternative 5 

Change in 

Residential Units 

from Alternative 1 

Total Visitor 

Lodging Units in 

Alternative 5 

Change in Visitor 

Lodging Units from 

Alternative 1 

Yosemite Village 390 -41 0 0 

Ahwahnee hotel 42 -6 123 0 

Curry Village 436 -146 453 53 

Yosemite Lodge 104 14 245 0 

Housekeeping 

Camp n/a n/a 232 -34 

Total Yosemite 

Valleya 972 -179 1053 19 

Rancheria 191 84 n/a n/a 

El Portal Village 92 12 n/a n/a 

Abbieville 0 0 n/a n/a 

Total El Portalb 283 96 n/a n/a 

a Totals include the 236 residential units that would be removed from the Curry Village and Yosemite Lodge areas of Segment 2 under 

actions common to Alternatives 2-6. 

b Totals include the 12 residential units that would be constructed in the El Portal Village area of Segment 4 under actions common to 

Alternatives 2-6. 
AFFECTED ENVIRONMENT AND ENVIRONMENTAL CONSEQUENCES

9-656 Merced Wild and Scenic River Comprehensive Management Plan / DEIS

Removal of 34 lodging units from Housekeeping Camp would eliminate a notable source of artificial 

lighting within the valley, including the interior cabin lighting, vehicle headlights, and campfires 

associated with this facility. However, these benefits would likely be offset by the increase in housing 

at Curry Village. Expanded parking at Camp 6 could increase artificial lighting through overhead 

lighting and/or from the headlights of greater numbers of vehicles departing the area after sunset. With 

continued operation of Yosemite Lodge and parking in the vicinity of the Lodge, lighting impacts in 

this area would also increase, mainly due to the increase in vehicles and parking lot lighting. Over the 

long-term, the impact of these actions on Segment 2 lightscapes would be local, negligible, and 

adverse. 

Under Alternative 5, the park would construct new housing for 84 employees within the Rancheria 

area of Segment 4. This project would contribute to area lightscape impacts through an increase in 

exterior lighting, the glow of interior lighting, and increased vehicle traffic. However, any new or 

modified exterior lighting would be required to comply with the park’s lighting guidelines and 

nighttime construction restrictions, incorporated by reference herein as mitigation measures 

MM-LITE-1 and -2 (see Appendix C). With mitigation, the long-term impact on Segment 4 would be 

local, minor to moderate, and adverse. Within Segment 7, the park would remove 13 campsites from 

the Wawona Campground. The corresponding reduction in overnight visitation within these areas 

would reduce lightscape impacts. The impact on Segment 7 would be local, long-term, negligible, and 

beneficial. 

Segments 2, 4, and 7 Impact Summary: Actions to manage user capacity, land use, and facilities 

would have local, long-term, adverse impacts on the lightscape environment, ranging from negligible 

to minor in Segments 2 and 4, and negligible beneficial in Segment 7. 

Summary of Impacts from Alternative 5: Enhanced Visitor Experiences and Essential 

Riverbank Restoration 

Lightscape impacts associated with Alternative 5 management measures would result mainly from 

changes in park visitation, facilities serving overnight visitors, and employee housing, and generally be 

limited to Segments 2 and 4. The collective effect of Alternative 5 management actions would cause 

overnight visitation within the park to increase considerably. However, because of the type and 

location of the shift in overnight accommodations (i.e., campgrounds near existing developed areas of 

the park), and with mitigation, the impacts associated with that visitation are expected to be minimal. 

New campground and lodging facilities would be developed within Yosemite Valley, in relative 

proximity to existing developed areas. The lightscape environment within El Portal would be further 

affected by the construction of a considerable amount of new employee housing. Taken together, it is 

expected that existing and potential future sources of human-caused lighting throughout the Merced 

River corridor would increase relative to Alternative 1, resulting in an overall long-term, local, 

negligible to minor, adverse impact on the park’s lightscape environment. 
Analysis Topics: Natural Resources 

Lightscapes – Alternative 5 

Merced Wild and Scenic River Comprehensive Management Plan / DEIS 9-657 

Cumulative Impacts from Alternative 5: Enhanced Visitor Experiences and Essential 

Riverbank Restoration 

Overall Cumulative Impact from Alternative 5: Enhanced Visitor Experiences and Essential 

Riverbank Restoration 

There are no anticipated development projects outside of those described here that would contribute 

to light pollution within the park. As a result, when combined with the impacts of past, present, and 

reasonably foreseeable actions, including those originating from outside the park, the cumulative 

effect of actions common to Alternatives 2-6 and those specific to Alternative 5 would be local, longterm, negligible, and adverse. 

Environmental Consequences of Alternative 6: Diversified Visitor Experiences and 

Selective Riverbank Restoration 

Segment 1: Merced River Above Nevada Fall 

Impacts of Actions to Manage User Capacity, Land Use, and Facilities 

Visitation within Segment 1 would not be expected to change appreciably under Alternative 6; 

wilderness access quotas would remain as under Alternative 1 and modifications to overnight 

accommodations would be nominal. As such, potential sources of artificial night lighting associated 

with overnight wilderness visitation would continue. Similarly, with designated camping unchanged, 

and with retention of several campground facilities, sources of artificial lighting (e.g., campfires) would 

remain concentrated within these areas of Segment 1. With continued operation of the Merced Lake 

High Sierra Camp at capacity, artificial lighting in the vicinity of the camp, including interior cabin 

lighting fixtures, would remain as under Alternative 1. The resulting impact on the environment within 

Segment 1 would be local, long-term, negligible to minor, and adverse. 

Segment 1 Impact Summary: Actions to manage user capacity, land use, and facilities would have a 

local, long-term, negligible to minor, adverse impact on the lightscape environment of Segment 1. 

Segments 2, 4, and 7: Yosemite Valley, El Portal, and Wawona 

Impacts of Actions to Manage User Capacity, Land Use, and Facilities 

Actions to manage visitor use and facilities under Alternative 6, specifically those concerning vehicle 

access and number of overnight accommodations, would contribute to a 33% increase in overnight 

visitation within Yosemite Valley. As discussed in the context of specific management actions below, 

this growth would affect an increase in valley-wide nighttime lighting through the corresponding shift 

in vehicles, lighted parking lots and lodging units, and other facilities to serve after-hours and 

overnight park visitors. 

As shown in table 9-129, a considerable number of campsites would be added within Segment 2. These 

additions would increase sources of nighttime lighting, such as campfires and vehicle lighting in several 
AFFECTED ENVIRONMENT AND ENVIRONMENTAL CONSEQUENCES

9-658 Merced Wild and Scenic River Comprehensive Management Plan / DEIS

TABLE 9-129: ALTERNATIVE 6 CAMPGROUND MODIFICATIONS

 Campsites 

(Alternative 6) 

Campsites 

(Alternative 1) 

Change from 

Alternative 1 

Yosemite Lodge and Camp 4 Areas 90 35 55 

Former Upper & Lower River Campground Areas 72 0 72 

Boys Town and Upper Pines Campground Areas 325 240 85 

Lower Pines Campground Area 71 76 -5 

North Pines and Backpackers Campgrounds and 

Curry Village Stables Areas 98 111 -13 

Eagle Creek and Yellow Pine Administrative 

Campgrounds 83 4 79 

Yosemite Valley Totalsa 739 466 273 

Wawona 86 99 -13 

Wawona Total 86 99 -13 

a Totals include the construction of 16 new sites near Backpackers Campground and 40 new sites near Camp 4 area under actions 

common to Alternatives 2-6. 

areas, including Camp 4, the Former Upper and Lower River Campground areas, and the Upper Pines 

and Eagle Creek Campground area. This increase would offset lightscape benefits resulting from removal 

of campsites from Backpackers, Lower Pines, and North Pines campgrounds. The net effect of these 

changes to the lightscape environment within Segment 2 would be long-term, local, minor, and adverse. 

As discussed in Environmental Consequences of Actions Common to Alternatives 2–6, and shown in 

table 9-130, the lightscape environment within Segment 2 would benefit from reductions in housing at 

Curry Village and the Yosemite Lodge areas. However, some of this benefit would be offset by the 

exterior glow of interior lighting, outdoor lighting, and continued vehicle traffic associated with the 

construction of new housing in the vicinity of Yosemite Village. 

Removal of 34 lodging units from Housekeeping Camp would eliminate a notable amount of artificial 

lighting within the valley, including the interior cabin lighting, vehicle headlights, and campfires 

associated with this facility. Expanded parking and expansion of the Concessioner Maintenance and 

Warehouse Building at Yosemite Village/Camp 6 would increase artificial lighting through new 

exterior lighting and more vehicle traffic (i.e., headlights) departing the area after sunset. With 

continued operation of the Yosemite Lodge and new campgrounds and parking in its vicinity, lighting 

impacts in this area would also increase, mainly due to the increase in vehicles and camping-related 

nighttime activities. Over the long-term, the impact of these actions on Segment 2 lightscapes would be 

local, negligible to minor, and adverse. 

Under Alternative 6, the park would construct new employee housing within the Abbieville and 

Rancheria areas of Segment 4. These projects would contribute to area lightscape impacts through an 

increase in exterior lighting, the glow of interior lighting, and increased vehicle traffic. However, any 

new or modified exterior lighting would be required to comply with the park’s lighting guidelines and 

nighttime construction restrictions, incorporated by reference herein as mitigation measures 

MM-LITE-1 and -2 (see Appendix C). With mitigation, the long-term impact on Segment 4 would be 
Analysis Topics: Natural Resources 

Lightscapes – Alternative 6 

Merced Wild and Scenic River Comprehensive Management Plan / DEIS 9-659 

TABLE 9-130: ALTERNATIVE 6 CONCESSIONER EMPLOYEE HOUSING AND VISITOR LODGING

 Location 

Total Residential 

Units in 

Alternative 6 

Change in 

Residential Units 

from Alternative 1

Total Visitor 

Lodging Units in 

Alternative 6 

Change in Visitor 

Lodging Units 

from Alternative 1

Yosemite Village 390 -41 0 0 

Ahwahnee hotel 42 -6 123 0 

Curry Village 436 -146 453 53 

Yosemite Lodge 104 14 440 195 

Housekeeping 

Camp 0 0 232 -34 

Total Yosemite 

Valleya 972 -179 1248 214 

Rancheria 151 44 n/a n/a 

El Portal Village 92 12 n/a n/a 

Abbieville 263 258 n/a n/a 

Total El Portalb 506 314 n/a n/a 

a Totals include the 236 residential units that would be removed from the Curry Village and Yosemite Lodge areas of Segment 2 under 

actions common to Alternatives 2-6. 

b Totals include the 12 residential units that would be constructed in the El Portal Village area of Segment 4 under actions common to 

Alternatives 2-6. 

local, moderate, and adverse. Within Segment 7, the Wawona stables would be removed and 13 

campsites eliminated from the Wawona Campground. The corresponding reduction in overnight 

visitation within these areas would reduce lightscape impacts. The impact on Segment 7 would be 

local, long-term, negligible, and beneficial. 

Segments 2, 4, and 7 Impact Summary: Actions to manage user capacity, land use, and facilities 

would have local, long-term, adverse impacts on the lightscape environment, ranging from minor to 

moderate in Segments 2 and 4, and negligible beneficial in Segment 7. 

Summary of Impacts from Alternative 6: Diversified Visitor Experiences and Selective 

Riverbank Restoration 

Lightscape impacts associated with Alternative 6 management measures would result mainly from 

changes in park visitation and facilities serving overnight visitors, and employee housing, and generally 

be limited to Segments 2 and 4. The collective effect of Alternative 6 management actions would cause 

overnight visitation within the park to increase. As discussed above, Alternative 6 management 

measures would add a considerable number of new lodging units, mainly campsites, within already 

developed areas of the park and some relatively remote areas of the park (i.e., the meadow east of 

El Capitan). Under Alternative 6, the lightscape environment within El Portal would be further affected 

by the construction of a substantial amount of new employee housing. Taken together, it is expected 

that existing and potential future sources of human-caused lighting throughout the Merced River 

corridor would increase relative to Alternative 1, resulting in a long-term, local, minor, adverse effect 

on the park’s lightscape environment. 
AFFECTED ENVIRONMENT AND ENVIRONMENTAL CONSEQUENCES

9-660 Merced Wild and Scenic River Comprehensive Management Plan / DEIS

Cumulative Impacts from Alternative 6: Diversified Visitor Experiences and Selective 

Riverbank Restoration 

Overall Cumulative Impact from Alternative 6: Diversified Visitor Experiences and Selective 

Riverbank Restoration 

There are no anticipated development projects outside of those described here that would contribute 

to light pollution within the park. As a result, when combined with the impacts of past, present, and 

reasonably foreseeable actions, including those originating from outside the park, the cumulative 

effect of actions common to Alternatives 2-6 and those specific to Alternative 6 would be local, longterm, minor, and adverse.