Other Studies
Another
method of soil classification uses the Unified Soil Classification
System for the purpose of the engineering design of structures.
Based on Unified Soil Classification System data, Yosemite
Valley
soils are generally classified as poorly sorted sand with varying
amounts of gravel, silt, and clay. Based on results of geotechnical
investigations performed at specific sites throughout the Yosemite
Valley
(HLA 1986, 1987a,
1987b, 1988;
Treadwell & Rollo 2003), these sand deposits are anticipated
to range from loose to medium dense in the upper 10
feet, gradually becoming dense to very dense at depth. Loose to
medium-dense
sand and gravel deposits pose several geotechnical engineering constraints
to the design of foundations and retaining walls.
A
soil and topography evaluation completed in November 2002 included a portion
of the Lower Pines Campground (Jones and Stokes 2002).
The purpose of the evaluation was to determine the thickness of
any fill material that was deposited over the land surface prior
to the construction of the Lower Pines and Upper Pines Campgrounds.
The evaluation found that fill material is present in various areas
and thicknesses. However, the dynamic geomorphic environment of
the Yosemite
Valley
floor makes it difficult to differentiate between artificial fill,
older overwash, and weakly developed, naturally deposited soil layers.
Thus, for the portion of Lower Pines Campground that was investigated,
it is possible that fill of less than 6
inches in thickness may be present.
Geologic Hazards
Yosemite National Park is located in a dynamic natural environment
subject to numerous geologic hazards associated with the high relief
of the central Sierra
Nevada
Mountains, the seasonal variations in Merced River flows, and the active tectonic provinces to
the west and east. Geologic hazards associated with these forces,
such as rockfalls, flooding, and earthquakes (seismic hazards),
affect the park and its visitors.
Seismicity
Earthquakes
felt in the Yosemite
Valley
usually have epicenters in western California or along the eastern flank of the Sierra Nevada. Historically, nine earthquakes (not including
aftershocks) have been felt and reported in the Yosemite Valley. Four of these quakes have triggered rockfall
events (Wieczorek et al. 1992). No active or potentially active
earthquake faults have been identified in the mountain region of
Yosemite National Park (Hart 1990). Earthquakes affecting Yosemite Valley have been generated on faults that lie west
and east of the Sierra
Nevada.
West of the Sierra
Nevada, seismogenic sources include the Foothills
Fault Zone, various faults along the western boundary of the Great Valley (Great Valley Thrust Zone), and the eastern
boundary of the San Andreas Fault Zone. To the east of the Sierra Nevada lies the Eastern Escarpment with its associated
seismogenic geological structures, including the Mono Craters–Long
Valley Caldera complex. Along the escarpment are bounding faults,
primarily within the Owens Valley Fault Zone, as well as active
faults in the Basin and Range Province to the east of the Sierra Nevada (CDMG 1996).
The
Foothills Fault Zone extends for approximately 220 miles in a north-south
direction within the foothills of the Sierra Nevada,
approximately 50 miles west of Yosemite Valley. This fault zone is capable of generating a
6.5
maximum moment magnitude earthquake
event (CDMG 1996). One significant historical event
of magnitude 5.7 occurred in 1975
near Oroville (CDMG 1975).
The
Basin and Range Province lies east of the Sierra Nevada and is the source of significant earthquake
activity. The Mono Lake fault, located approximately 35
miles northeast of Yosemite Valley within the Mono Craters–Long
Valley Caldera region, is characterized as active (CDMG 1996) and capable of a 6.6
maximum moment magnitude event. In October 1990, the Mono Lake fault experienced a 5.7 Richter movement. This earthquake was felt as far west
as Sacramento and the San Francisco Bay Area and caused landslides
and rockfalls at Tioga Pass and on the Big Oak Flat Road (McNutt et al. 1991).
In May 1980 there was a sequence of earthquakes at Mammoth Lakes; four of the earthquakes measured Richter magnitude
6.0 to 6.2
and triggered nine rockslides and rockfalls at Yosemite Valley, approximately 44
miles west of the epicenters (Treadwell & Rollo 2003).
The
project area is located in seismic zone 3, as defined by the Uniform Building
Code Seismic Zone Map (UBC 1997). No active or potentially active
earthquake faults have been identified in the mountain region of
Yosemite National Park (Hart 1990). As described above, Yosemite can undergo strong seismic shaking associated
with earthquakes on fault zones to the east and west margins of
the Sierra Nevada range, as has occurred in the past. Ground
shaking can be expressed as peak acceleration due to gravity as
a percent of 1 g
(g is acceleration due to gravity, or 32 feet per second). The potential estimated
peak horizontal accelerations produced by the various regional faults
in the central California and Sierra Nevada region are relatively low and could range between
0 and 0.2 g (CDMG 1999). Most
people would likely feel this range of ground shaking, but structural
damage would be negligible to slight in buildings constructed on
firm soil or rock according to modern building standards.
Soil
liquefaction is a phenomenon where loose, saturated, cohesionless
soil experiences a temporary loss of strength during strong cyclic
loading conditions such as those induced by earthquakes. The type
of soil most susceptible to liquefaction is loose, clean, saturated,
and uniformly graded, fine-grained
sand. Based on the depositional environment within the Valley and
previous geotechnical investigations performed within the Valley
(HLA 1986, 1987a,
1987b, 1988;
Treadwell & Rollo 2003), loose, relatively clean sand can
be anticipated at shallow depths in the project area and could liquefy
during an earthquake. If the groundwater level rises to the ground
surface or higher (during flooding) and an earthquake occurs during
the period of high groundwater, all of the loose sands could liquefy.
The amount of liquefaction is based on the thickness of potentially
liquefiable soil and could range up to 2
inches or more. Strong earthquake shaking can also densify relatively
loose, unsaturated sands. Consequently, the loose sands in the project
area could also densify when groundwater is at low levels, such
as during late summer.
Rockfalls
Rockfall
is used as a generic term to refer to all slope movement processes,
including rockfalls, rockslides, debris slides, debris flows, debris
slumps, and earth slumps. Rockfalls are part of the natural erosion
and weathering of the steep granitic slopes in the Valley. Rockfalls
can incorporate large volumes of rock and are known to be triggered
by freeze/thaw cycles, heavy precipitation and runoff, seismic shaking,
and natural exfoliation processes. The magnitude and proximity of
the earthquake, intensity and duration of the rainfall or snow melt,
and the intensity of the freeze/thaw cycle all influence the location
and volume of rockfalls. However, some rockfalls occur without a
direct correlation to an obvious triggering event. These are probably
associated with gradual stress release and natural exfoliation processes
of the granitic rocks (Wieczorek et al. 1998). More than 400 rockfalls have been recorded within
Yosemite National Park; some have resulted in injury and, on occasion,
death. Rockfalls can also damage or destroy roads, trails, and buildings
(Royston, Hanamoto Alley & Abey 1997).
Based
on the rockfall deposits mapped along the Valley margin, and studies
of the kinematics of rockfall events, two distinct zones of hazard
exist. The talus zone is the first hazard zone and is defined by
the very prominent cone-shaped
boulder deposits that line the Valley margin at areas of frequent
rockfall. This area was first mapped in 1930 to show the effect of rockfalls
on the accumulation of geologic materials beneath the Valley floor.
Portions of Curry Village, South Camp, and Upper Pines Campground are
located within both the talus zone and the rockfall zone, as illustrated
by figure III‑2. Much of Curry Village is built among large boulders deposited by
several large prehistoric rockfalls, but no comparably sized rockfall
events have occurred during the last 150 years (Wieczorek and Snyder 1999).
Many
small rockfalls are observed every year in Yosemite Valley, while larger-size rockfalls occur less frequently.
Wieczorek and others (1998) have determined an 11-year
recurrence interval for the Happy Isles rockfall, which had a volume
of approximately 30,000
cubic meters. Isolated boulders have been mapped beyond the extent
of the obvious talus cones, in the area known as the rockfall zone.
The rockfall events that deposited these isolated boulders pose
a lower hazard.
Avalanches
are another type of rockfall hazard. Avalanches move as a coherent
mass of rock debris capable of trapping air beneath it and traveling
long distances into the Valley. The locations or paths of such events
have not been determined. Avalanches are rare occurrences in Yosemite
Valley.
However, the prehistoric avalanche mapped below Royal Arches extends
820 feet beyond the
mapped rockfall zone (Wieczorek and Snyder 1999).
Due to the configuration of the high, steep Valley walls and the
relatively narrow Valley, there are probably no areas in Yosemite Valley that are absolutely safe from avalanche rockfalls.
Debris
flow landslides are not as common as rockfalls in the Valley, but
they still pose a hazard. Debris flows have a higher proportion
of water than other landslide types and can transport boulders longer
distances over relatively gentle slopes. At Upper Pines Campground,
successive deposition of debris flows has built a fan that extends
beyond the limit of the rockfall zone.A series
of rockfalls from the north face of Glacier Point above Curry Village in June through July 1999
led to re-examination of rockfall hazards, which identified a
system of fractures in a rock mass in the source zone of the falls
(Wieczorek and Snyder 1999). The National Park Service, in
cooperation with the U.S. Geological Survey, is currently identifying
potential geologic hazards in developed areas, including areas most
susceptible to rockfalls (Wieczorek et al. 1998). The National Park Service is revising
its management policies regarding geologic hazards, with the intent
to better protect park visitors and staff by avoiding placement
of structures in areas with a high potential for rockfall hazards.
The National Park Service policy is reflected in the Geologic
Hazard Guidelines, provided in Appendix B.
Floodplains
The
Merced River
basin can be divided into three hydrologic
segments: the upper Merced River, Yosemite
Valley, and the Merced River
gorge (which includes the El Portal Administrative Site). This division
is based on the unique watershed characteristics of the three river
areas. Discharge flows within the different areas reflect the contribution
of the overall watershed. The project area is located within Yosemite
Valley.
Yosemite Valley Watershed
The
Yosemite Valley watershed includes Yosemite
Valley and its tributary areas, as well as Curry
Village and the campground
sites. The main tributaries to the Merced River
in Yosemite Valley are Tenaya Creek, Illilouette
Creek, Yosemite Creek, and Bridalveil Creek. At Pohono
Bridge, where the Yosemite
Valley watershed ends and the Merced River
enters the narrow, steep-sided
Merced River gorge, the overall Merced
River basin encompasses
205,000
acres (321 square
miles) (USGS 1999). Historic flow measurements in
the river at the Pohono Bridge Gauging Station have ranged from
a high of about 25,000 cubic feet per second to a low of less than 10 cubic feet per second. The mean average
daily flows are highest in May and June (approximately 2,000 cubic feet per second) and lowest
during the months of September and October (less than 100 cubic feet per second) (USBR 2001).
During
the most recent period of glaciation in Yosemite Valley, a glacier extended to approximately the location of Pohono Bridge. Following glacial retreat, a large lake (Lake Yosemite) developed and eventually filled with sediment
from the El
Capitan
moraine to upstream of Happy Isles (Huber 1989). The resulting Valley floor has
a very mild slope and is responsible for the meandering pattern
of the present-day
river.
The
Yosemite Valley segment of the Merced River is characterized by a meandering river, world-renowned waterfalls, an active flood regime, oxbows,
unique wetlands, and fluvial processes. The Merced River has a relatively mild slope, with an average
of 0.1% through Yosemite Valley (USGS 1992). The Merced River is an alluvial river within Yosemite Valley, and the bed and banks of the channel are composed
of smaller sediments, cobbles, and soil layers. This condition makes
for a dynamic river that alters its course periodically by eroding
and depositing bed and bank material. In most locations, the river
flows through a shallow channel approximately 100 to 300 feet wide. In
the middle of Yosemite
Valley,
the river has the capacity to convey a 2- to 5-year
flow within the existing channel banks (NPS 1997a).
Eleven
bridges cross the Merced
River
between Happy Isles and the Pohono Bridge. Many of these bridges influence the width,
location, and velocity of the Merced
River
(NPS 2000a). In a
natural river channel, the streambanks slope at an angle away from
the stream, resulting in a wider channel as flows increase. However,
bridges with arched abutments that obstruct the free flow of the
Merced River confine river flows and result in a narrowing
of the channel as flows increase. The narrowing of the channel accelerates
the velocity of the river through the bridge, causing increased
channel scouring directly downstream. If flow cannot be conveyed
through a bridge during periods of high discharge, water backs up
behind the bridge. This backwatering can inundate low-lying areas or overflow channels.
The Merced
River within Yosemite Valley is constricted at all bridge sites between
Happy Isles and Pohono
Bridge (Milestone 1978).
Alluvial
Processes
Yosemite
National Park is composed
of and underlain by various granite rock types; as a result, weathering,
erosion, and transport of sediment can be very slow processes. Areas
of Yosemite National
Park have significant soil layers where
clays, silts, and organic debris have accumulated with the gravels
and sands of the decomposed bedrock. These soils are subject to
erosion and alluvial processes.
Sedimentation
is a significant process within Yosemite Valley.
The Merced River has a very low gradient
within the Yosemite Valley, approximately
0.1%,
or 6.25 feet per mile (Smilie et al. 1992). This low gradient allows for significant sediment
deposition within Yosemite Valley and the
formation of the meandering Merced River
through this reach. River impoundments such as bridges and dams
tend to alter the sediment distribution and formative streamflows,
thereby disrupting the natural alluvial processes.
Floodplains
A
floodplain plays a necessary role in the overall adjustment of a
river system. It exerts an influence on the hydrology of the basin
and also provides temporary storage for sediment eroded from the
watershed. Periodic flooding provides sediment and nutrients that
are essential for the aquatic and vegetative health of the floodplain.
Floodplains are features that are both the products of the river
environment and important functional parts of the system. Human-made
structures such as bridges and buildings placed within a floodplain
can impede natural flow and result in injury to visitors and damage
to structures during flood events. Discussion of flooding and floodplains
is most relevant in terms of the potential loss of life and the
influence on the river by development in the floodplain.
Yosemite
Valley has a well-developed floodplain, with major
roads and structures along or within both sides of the floodplain.
The character of the floodplain varies in different locations because
of local hydraulic controls. The 100-year floodplain is typically used to define the general floodplain
boundary. The Merced River watershed has
had 11 winter floods since 1916 caused by warm winter rains falling
on snow and partially melting the accumulated snowpack. The January
1997 flood was the largest recorded within
the park; it was estimated to have a recurrence interval of 90 years (NPS 1997c). The flood inundated roads, picnic
areas, park offices, and lodging units. The U.S. Geological Survey
estimated that the flood had a peak discharge of 10,000 cubic feet per second at Happy Isles
and 25,000 cubic feet per second at Pohono
Bridge (Eagan
1998). The portions
of the development areas that were within the 1997
flood extent are shown in table III‑2. Curry
Village and South Camp
were not within the flood extent, while portions of the amphitheater,
Upper Pines Campground, and Lower Pines Campground were between
23 and 70%
flooded.
|
Table
III-2
1997 Flood Extent |
|
Development
Area Name
|
Total
Area
(Acres)
|
Area
Within 1997 Flood Extent (Percent)
|
|
Amphitheater
|
0.91
|
70
|
|
Curry
Village
|
65.43
|
0
|
|
Lower
Pines
|
10.7
|
23
|
|
South
Camp
|
10.47
|
0
|
|
Upper
Pines
|
54.89
|
26
|
|
Sources:
NPS GIS Database, EDAW 2003
|
The
floodplain of the Merced River is well-developed
in some sections, such as in meadow areas in Yosemite
Valley. In other areas, the floodplain is lacking due
to narrowing canyon/valley walls, which occurs in west Yosemite
Valley.
From
Clark’s Bridge to Housekeeping Camp in the
east Valley, the Merced River floods areas
outside the main river channel with shallow, swift flows that cut
across meander bends. Farther downstream of Housekeeping Camp to
the El Capitan moraine (to the west of the
project area), the floodplain becomes broader and well developed.
In that area, flood water energy is dissipated as it spreads out
over the flatter and more expansive plain. Stoneman Meadow, which
lies between Lower Pines Campground and Curry
Village, is located within
the floodplain and is maintained and rejuvenated by periodic flood
waters.
Water
Quality
Water
quality throughout Yosemite National Park
is considered to be good and generally above state and federal standards.
The state of California
considers the surface water quality of most park waters to be beneficial
for wildlife habitat, freshwater habitat, contact and noncontact
recreation, canoeing, and rafting, as indicated in the Central Valley
Regional Water Quality Control Board’s Water Quality Control Plan
(Basin Plan). An inventory of water quality data performed by the
National Park Service indicated excellent conditions in many parts
of the park, but some water quality degradation was noted in areas
of high visitor use (NPS 1994b).
Occasional
concentrations of lead, cadmium, and mercury above drinking water
and freshwater criteria have been measured within the Merced
River (NPS 1994b).
Potential sources of these metals include leaded gasoline, stormwater
runoff from developed surfaces such as parking lots, wastewater
discharge, campsites, and fuel storage facilities.
Water
quality has been affected by the extensive and concentrated visitor
use of the Merced River in popular areas.
High use of the streambank induces bank erosion through the loss
of vegetative cover and soil compaction. Bank erosion can result
in the widening of the river channel and loss of riparian and meadow
floodplain areas. Water quality is then altered through increased
suspended sediments due to erosion, higher water temperatures from
a lack of riparian cover, and lower dissolved oxygen levels due
to elevated temperatures and shallower river depths.
Human
activities, including the use of vehicles, can distribute water
pollutants that collect on land surfaces and are later transported
into the river or its tributaries by stormwater runoff. Such activities
are referred to as nonpoint
sources because the pollutants they generate accumulate from
various areas and do not originate from a single point
source (such as an outfall pipe). Construction activities that
disturb soil, generate dust, and cause occasional petroleum releases
from equipment and vehicles can represent a short-term
nonpoint pollution source. Recreational activities such as horseback
riding, swimming, and hiking can lead to the introduction of organic,
physical, and chemical pollutants into aquatic systems. Nonpoint-source runoff from roads and parking lots may potentially
affect water quality by introducing organic chemicals and heavy
metals.
Water
quality parameters have been measured by the U.S. Geological Survey
at the Happy Isles Gauging Station from approximately 1970 through 2001. Surface water is of high quality in most areas, although
water quality can be stressed in areas near human development (NPS
2000a). At the Happy Isles Gauging Station,
upstream and east of the project area, surface water chemistry exhibits
near-neutral
pH, low electrical conductivity (limited ions due to a lack of dissolved
solids), and low nutrient concentrations (USGS 1996).
Groundwater
Quality Characteristics
Groundwater
quality is generally good in the Merced
River basin; groundwater
is the sole source of potable water for Yosemite Valley
and El Portal. There are locations in Yosemite Valley
where relatively high iron concentrations in groundwater result
in reddish deposits on the ground surface, such as the springs near
lower Tenaya Creek and several locations on the Merced
River (Williamson et al. 1996). These iron concentrations are
naturally occurring and are not a threat to water quality. Federal
regulations require that potable water systems that rely on groundwater
be continually monitored and operated within set levels for turbidity,
waterborne pathogens, and other potential pollutants.
Wetlands
Regional Context
Aquatic
and riparian systems are the most altered and impaired habitats
of the Sierra Nevada (UC Davis 1996a–d). Dams and diversions throughout
most of the range have profoundly altered streamflow patterns and
water temperatures. Foothill areas below 3,300 feet appear to have the greatest
loss of riparian vegetation of any region in the Sierra
Nevada (UC Davis 1996a–d).
Within the mountains, broad valleys with wide riparian areas were
often reservoir sites, and much of the best former riparian habitat
in the Sierra Nevada is now under water.
The extent of the inundation across the range becomes apparent when
one realizes that virtually all flat-water on the western slope of the
Sierra Nevada below 5,000 feet is artificial (UC Davis 1996a–d). Wetlands in the Sierra
Nevada have been drained since the earliest settlers
attempted to reclaim meadows and other seasonally wet areas. Mountain
meadows were commonly drained with the intent of improving forage
conditions and to permit agriculture (NPS 1997b;
UC Davis 1996a–d).
Wetland
Classification and Definition
Wetlands
are ecologically productive habitats that support a rich array of
plant and animal life. They sustain a great variety of hydrologic
and ecological functions vital to ecosystem integrity. These functions
include flood abatement, sediment retention, groundwater recharge,
nutrient capture, and high levels of plant and animal diversity.
Wetlands and riparian areas are relatively rare compared to the
overall landscape. When wetlands are converted to systems that are
intolerant of flooding (drained agricultural lands, filled developed
lands), their storage capacity decreases and downstream flooding
increases (NPS 1997b).
Modification of even small wetland areas induces effects that are
proportionally greater than elsewhere in an ecosystem (Graber 1996). Although there are several definitions
for the term wetland, the two used herein follow National Park Service
and U.S. Army Corps of Engineers conventions, as described below.
The
National Park Service classifies and maps wetlands using a system
created by the U.S. Fish and Wildlife Service, often referred to
as the Cowardin classification system (USFWS 1979).
This system classifies wetlands based on vegetative life form, flooding
regime, and substrate material. Wetlands, as defined by the U.S.
Fish and Wildlife Service and adopted by the National Park Service,
are lands in transition between terrestrial and aquatic systems,
where the water table is usually at or near the surface, or the
land is covered by shallow water. For purposes of this classification,
wetlands must have one or more of the following attributes:
§
The land supports predominantly hydrophytes, at least periodically.
Hydrophytes are plants that grow in water or on a substrate that
is at least periodically deficient in oxygen as a result of excessive
water content.
§
The substrate is predominantly undrained hydric soils. Hydric soils
are wet long enough to periodically produce anaerobic conditions.
§
The substrate is saturated with water or covered by shallow water
at some time during the growing season of each year (USFWS 1979).
Under
Section 404 of the
Clean Water Act, the Corps of Engineers issues permits for the discharge
of dredged or fill material into “waters of the United States” (33 Code of Federal Regulations 323.3).
Wetlands are a subset of waters of the United
States and receive jurisdictional
protection under Section 404 of the Clean Water Act. Waters of the United
States (also regulated under Section
404 of the Clean Water Act) include features
such as streams, rivers, bays, lakes, inlets, mudflats, washes,
sloughs, sandflats, territorial seas, tributaries, and impoundments.
Wetlands are defined under the Clean Water Act as follows: “Those
areas that are inundated or saturated by surface water or groundwater
at a frequency and duration sufficient to support, and that under
normal circumstances do support, a prevalence of vegetation typically
adapted for life in saturated soil conditions” (33
Code of Federal Regulations 328.3[b]).
The
Cowardin system and the Corps of Engineers both use the three parameters
to define wetlands: hydrophytic vegetation, hydric soil, and wetland
hydrology. However, the Cowardin system defines more habitat types
as wetlands than does the Corps of Engineers definition. The Cowardin
system also recognizes that many unvegetated sites (e.g., mudflats,
stream shallows, saline lakeshores, playas, deepwater) or sites
lacking soil (e.g., rocky shores, gravel beaches) are wetland habitats.
The reason these sites lack hydrophytic vegetation and/or hydric
soil is due to natural chemical or physical factors. Although the
Corps of Engineers does not consider these sites to be wetlands,
they are still subject to regulations under Section 404
of the Clean Water Act as “other waters of the United
States.”
The
Corps of Engineers also has jurisdiction over navigable waters of
the United States
under Section 10
of the Rivers and Harbors Act of 1899.
Navigable waters of the United States
are those waters that are subject to the ebb and flow of the tide
and/or are currently used, or have been used in the past, or may
be susceptible for use to transport interstate or foreign commerce.
A determination of navigability, once made, applies laterally over
the entire surface of the water body and is not extinguished by
later actions or events that impede or destroy navigable capacity
(33 Code of
Federal Regulations 329.4). No portion of the Merced
Riverwithin Yosemite
National Park is designated
as navigable waterway under Section 10
of the Rivers and Harbors Act.
Yosemite
Valley Wetlands
Riverine
The
riverine classification includes all the wetland and deepwater habitats
contained within a river channel, except wetlands dominated by trees,
shrubs, persistent emergent mosses, or lichens. A channel is “an
open conduit either naturally or artificially created which periodically
or continuously contains moving water, or which forms a connecting
link between two bodies of standing water” (USGS 1960).
§
Riverine Forested. This
wetland type consists of white alder, black cottonwood, and various
species of willows growing at the edge of the channel of the Merced
River, Tenaya Creek, or any of the intermittent watercourses
of the project sites.
§
Riverine Intermittent Streambed.
This wetland type consists of the smaller watercourses that flow
in the winter, spring, and summer during periods of runoff and snow
melt. The channels are typically bare, but the edges often support
palustrine emergent vegetation.
§
Palustrine. The palustrine classification includes
vegetated wetlands, but can also include nonvegetated wetlands that
are less than 20
acres, less than 6.5 feet in the deepest part at low water, and do not have
a wave-formed
or bedrock shoreline. Palustrine wetlands can occur as isolated
wetlands, on river floodplains, and along lake or pond shores. Palustrine
wetlands include riparian corridors, marshes, and ponds.
§
Palustrine Emergent. This
wetland type includes meadows, marshes, and vegetated ponds. Emergent
wetlands are characterized by erect, rooted, herbaceous hydrophytes
that are usually present for most of the growing season.
§
Palustrine
Forest. These riparian forest habitats are regularly
inundated by normal high-water
flows or flood flows. The dominant woody vegetation is at least
20 feet tall.
§
Palustrine Scrub Shrub. This
wetland type includes areas dominated by woody vegetation less than
20 feet tall, such
as small willows.
Curry Village and East Yosemite Valley Campgrounds Wetlands
Wetlands
in the project area were mapped by Jones & Stokes (2002),
under contract to the National Park Service. The Cowardin classification
method, based on habitat type, was used to determine the location
of wetlands. Wetland acreages were not calculated. Wetlands located
in the project area are shown in Appendix E on figures E‑1, E‑2, and E‑3. Table III‑3
indicates the types of wetlands located in the project planning
areas.
|
Table
III-3
Project Planning Areas – Wetlands |
|
Site
|
Wetland
Type
|
|
Curry
Village
|
Palustrine
forest, palustrine emergent, palustrine scrub shrub, and riverine
intermittent streambed
|
|
South
Camp
|
Palustrine
emergent and riverine intermittent streambed
|
|
Upper
Pines
|
Palustrine
forest, palustrine emergent, palustrine scrub shrub, and riverine
intermittent streambed
|
|
Lower
Pines
|
Palustrine
scrub shrub and riverine intermittent streambed
|
|
Amphitheater
|
None
|
|
Sources:
NPS 2000a; NPS GIS Database 2003
|
Vegetation
Riparian Plant Communities
Riparian
areas and low-elevation
meadows are the most productive communities in Yosemite
Valley. The high quality and large extent of riparian,
wetland, and other riverine areas provide rich habitat for a diversity
of river-related species. Riparian vegetation is limited within
the project area to those areas adjacent to watercourses. This vegetation
is composed of black cottonwood, white alder, black oak, various
species of willow (e.g., red willow, sandbar willow, and arroyo
willow), ponderosa pine, and Douglas-fir.
Herbaceous
species such as rush, sedge, and horsetail are present in the understory.
A riparian community dominated by big-leaf maple occurs on the slopes
of the Valley. Riparian vegetation borders the Merced
River in the project area. Vegetation in the project
area is shown in figure III‑3.
California Black Oak Communities
California
black oaks on the floor of Yosemite Valley
form pure, open stands of large, stately trees with an herbaceous
understory. These pure stands – unique to the Yosemite
Valley due to thousands of years of anthropogenic activities,
such as annual burning and removal of young conifers – are found
at the change in slope between upland colluvial deposits and lower,
water-driven
alluvial areas. They form a band of oaks around the Yosemite
Valley floor between the upland plant communities and
the lower-lying meadow and riparian communities. An area of black
oak woodlands occurs at the northern edge of the proposed amphitheater
site in the project area.
The
California black oak
acorn was a primary food source of American Indians in Yosemite
Valley, and most of the large groves continue to be
used as traditional gathering areas today. California
black oak stands mixed with ponderosa pine are found throughout
Yosemite Valley, and additional areas of
California black oak
that contain buildings and other development are found in east Yosemite
Valley. California
black oaks also grow in dense stands on talus slopes near drainages,
but for the purposes of this analysis, talus black oaks are grouped
with the other upland communities. California
black oak communities are considered a highly valued natural and
cultural resource in Yosemite Valley.
California
black oak communities in Yosemite Valley are identified as sensitive
due to declines in population size, vigor, and recruitment rates,
and have been included in the highly valued resources map (NPS 2000a,
Vol. IC, plate D). Changes in natural or cultural fire processes,
encroachment by conifers, browsing by deer and rodents, impacts
from development, and unmanaged visitor use have all caused a significant
decline in density and stand structure (Fritzke 1997).
Oak woodlands are also some of the most ecologically transformed
terrestrial ecosystems in the Sierra Nevada
due to alterations of natural processes, development, and the introduction
of non-native species. The conversion of California
black oak woodlands has also had a substantial effect on wildlife
species (UC Davis 1996c).
Armillaria
species are fungi that attack the root and crown of hardwoods and
conifers of all ages. These fungi can be found on nearly every California
black oak in Yosemite Valley. Armillaria mellea can kill disturbed or severely stressed oaks and
is apparently favored by high levels of soil moisture during the
summer. Summer watering of California
black oaks in landscaped areas has contributed to the overall decline
of this community in Yosemite Valley.
California
black oak communities are adapted to frequent, low-intensity fires, similar to upland mixed conifer communities.
Under natural conditions, the return interval for fire is estimated
at 8 to 12 years (NPS 1990). Non-native
plant species have also become established in California
black oak communities.
Due
to past and current levels of disturbance in this community, non-native
species have become more widespread than in upland forests. These
non-native species include annual grasses,
black locust, American elm, and extensive ground-covering stands of Himalayan blackberry.
The locations of Himalayan blackberry stands in the project area
are indicated on figure III‑3.
Upland
Plant Communities
Upland
plant communities are found where soil moisture conditions are average
to dry and where soils are not periodically flooded or saturated.
In the project area, these communities fall into the categories
of montane hardwood, montane hardwood conifer, and ponderosa pine.
Upland
Plant Communities
Upland
communities are much more common, widespread, and vegetatively intact
than California black
oak, riparian, or meadow communities in Yosemite Valley
as well as throughout the Sierra Nevada (NPS
1994d; UC Davis 1996e). However, they have undergone
alterations through changes in fire frequency, spread of native
root rot, and establishment of non-native
species.
The
montane hardwood type is dominated by canyon live oak. This type
occurs on both north-
and south-facing
talus slopes and often forms pure or almost pure stands. Fires in
this community are infrequent but intense, with a fire return interval
of 20 to 50
years on south-facing
slopes. Most trees and shrubs in this community are adapted to resprout
after fire.
Montane
hardwood conifer vegetation is normally dominated by ponderosa pine
and/or incense-cedar
and generally grows at elevations of 3,000 to 5,000 feet. This community also contains
Douglas-fir,
white fir, and California
black oak. Pacific dogwood is a common associate. An occasional
canyon live oak also occurs in this community. Understory was largely
absent from the areas in the Valley.
Montane
hardwood conifer vegetation is adapted to low-intensity, frequent fires. Nearly
100 years of fire
suppression has resulted in a change from open forest to dense thickets
of shade-tolerant tree species (including
incense-cedar,
white fir, and Douglas-fir)
in many areas. Under natural conditions, the return interval for
fire is estimated at 8 to 12
years (NPS 1990).
Existing conditions, however, often generate fires of much greater
intensity than under a natural fire regime. Most undeveloped mixed
conifer areas of Yosemite Valley are now
managed through a combination of mechanical removal of hazardous
fuel and prescribed burning. These treatments simulate the natural
and anthropogenic fire regimes of the Yosemite Valley
and help decrease stand densities to more natural levels.
Annosus
root disease is a widespread native fungus occurring throughout
northern Europe and western North
America in coniferous forests. In pines, the fungus
first spreads through the root system, attacking and eventually
killing the inner bark and sapwood. Within two to six years after
initial infection, the tree can die, leaving the fungus active as
a saprophytic, wood-decaying
organism within roots and the butt of the dead tree. Pines weakened
by annosus root disease are often killed by bark beetles. Incense-cedars, however, are not affected by beetles and will
stand green for many years, until the disease finally weakens the
structure enough to cause failure. Cedars are thought to act as
reservoirs for annosus root disease (NPS 1998c).
In
Yosemite Valley, the large size of annosus-root-disease centers is unusual; only
a few other large population centers of this species occur on the
western side of the Sierra Nevada. Yosemite
Valley has dense stands of large trees on a sandy floor,
a high water table, and frequent flooding. The conifer forest in
Yosemite Valley may not be sustainable because
of these large centers of annosus that have developed within the
unnaturally dense stands of conifers in former California
black oak, meadow, and riparian areas.
Emergent
Wetlands and Wet Meadow
Fresh Emergent Wetland
This
vegetation is found in areas that are flooded frequently by streams
and runoff, resulting in vegetation dominated by water-loving plants (hydrophytes). The
cycle of flooding and drying in these areas causes much plant decomposition,
supporting a rich nutrient cycle. Fresh emergent wetland is the
second scarcest habitat type in Yosemite Valley,
occupying just 0.43%
of the Yosemite Valley.
Wet
Meadow
Wet
meadow vegetation generally has a simple structure composed of a
layer of herbaceous plants and occurs in places where water is at
or near the surface during most of the growing season. While shrubs
and trees are usually absent or sparse, they can be an important
habitat component adjacent to the meadow. Within the herbaceous
plant community, habitat layers are often present on a smaller scale,
with various plant species growing to different heights.
Curry Village and East Yosemite Valley Campground Vegetation
Vegetation
within the project area can be characterized primarily as riparian
and upland. Figure III‑3 illustrates the varieties of vegetation
in the project area. The Vegetation
Management Plan (NPS 1997b) provides more detailed descriptions
of vegetative communities, including distributional limits, habitat
requirements, community sensitivities, and a list of plant species
characteristically found in conjunction with each plant assemblage.
Table III‑4
identifies the vegetation within each project planning area.
|
Table III-4
Project Planning Areas – Vegetation
|
|
Site
|
Vegetation
Type
|
|
Curry Village
|
Riparian,
montane hardwood conifer, ponderosa pine, and wet meadow.
Downed wood and understory species are largely absent from
the montane hardwood conifer and ponderosa pine types. Pacific
dogwood and a species of currant occur in the understory.
The riparian vegetation consists of a broad-leaf species
along a low-lying area beside the apple orchard and big-leaf
maple trees growing on the slopes south of Curry
Village.
|
|
South
Camp
|
Ponderosa
pine with some montane hardwood conifer and fresh emergent
wetland. Pacific dogwood is present as a small understory
tree. The understory of this vegetation is largely absent,
and there is little downed wood or logs on the forest floor.
|
|
Upper
Pines
|
Montane
hardwood conifer with some ponderosa pine and fresh emergent
wetland. Pacific dogwood is present as a small understory
tree. Campers have removed all of the dead wood from the
understory. Understory shrubs are few.
|
|
Lower
Pines
|
Montane
hardwood conifer with some ponderosa pine. Campers have
removed all of the dead wood from the understory. Understory
shrubs are few.
|
|
Amphitheater
|
The
amphitheater site is located in a parking lot of the stable
and a wet meadow area. California black oak occurs nearby.
|
|
Sources:
NPS GIS database, EDAW 2003
|
Wildlife
Yosemite Valley is a broad, U-shaped valley characterized by black
oak woodland, lower montane mixed coniferous forest, a riparian
corridor along the Merced
River,
low-elevation
meadows, and areas of development. In Yosemite Valley, the Merced
River
is broad, shallow, and slow moving (compared to other systems).
The high quality and large extent of riparian, wetland, and other
riverine areas provide rich habitat for a diversity of river-related species.
Riparian
restoration efforts are underway along the banks of the Merced River in the Yosemite Valley and are likely to have a positive effect on
fish populations. In 1997 and 1998,
surveys were conducted to examine the effects of riverbank restoration,
with special attention to the presence of large woody debris and
the association of fish to those areas. Rainbow trout density appeared
higher at restoration sites, while the density of browns and suckers
was higher at the control sites (USFWS 1998).
Curry Village and East Yosemite Valley Campground Wildlife
Within
Yosemite Valley, concentrated areas of human use have affected
wildlife and their habitats, especially within the project sites.
Table III‑5 identifies the wildlife present in
the project planning areas.
|
Table III-5
Project Planning Areas – Wildlife
|
|
Site
|
Wildlife
|
|
Curry Village
|
Wildlife includes deer mouse, western gray
squirrel, broad-footed mole, Botta’s pocket gopher, ringtail,
raccoon, coyote, mule deer, and black bear. The constant presence
of people results in a reduced habitat value compared to those
areas in which people are not present.
|
|
South
Camp
|
Wildlife includes deer mouse, western gray
squirrel, broad-footed mole, Botta’s pocket gopher, ringtail,
raccoon, coyote, mule deer, and black bear. The constant presence
of people results in a reduced habitat value compared to those
areas in which people are not present.
|
|
Upper
Pines
|
Wildlife includes deer mouse, western gray
squirrel, broad-footed mole, Botta’s pocket gopher, ringtail,
raccoon, coyote, mule deer, and black bear. The constant presence
of people results in a reduced habitat value compared to those
areas in which people are not present. Nevertheless, a portion
of the North Pines site, across from an intermittent drainage,
supports greater wildlife value because of its isolation from
the existing camping area.
|
|
Lower
Pines
|
Wildlife includes deer mouse, western gray
squirrel, broad-footed mole, Botta’s pocket gopher, ringtail,
raccoon, coyote, mule deer, and black bear. The constant presence
of people results in a reduced habitat value compared to those
areas in which people are not present.
|
|
Amphitheater
|
The amphitheater site is located in a parking
lot of the stable and a wet meadow area. The species present
would be the same as at the other sites: deer mouse, western
gray squirrel, broad-footed mole, Botta’s pocket gopher, ringtail,
raccoon, coyote, mule deer, and black bear.
|
|
Source:
NPS 2000a
|
Mammals
resident or transient in the project planning areas include deer
mouse, western gray squirrel, broad-footed mole, Botta’s pocket gopher,
ringtail, raccoon, coyote, mule deer, and black bear. Heavy visitation
to Yosemite
Valley and its relatively high number of resident
employees have led to many human/wildlife conflicts. The root of
most of these problems is the availability of human food. Improperly
stored food and garbage and deliberate feeding alter the natural
behavior of wildlife and lead to property damage and threats to
human safety.
Special-Status Species
The
Federal Endangered Species Act of 1973, as amended, requires all federal
agencies to consult with the U.S. Fish and Wildlife Service before
taking actions that could jeopardize the continued existence of
species that are listed or proposed to be listed as threatened or
endangered, or could result in the destruction or adverse modification
of critical or proposed critical habitat. The first step in the
consultation process is to obtain a list of protected species from
the U.S. Fish and Wildlife Service. Special-status
species in the project area are shown in figure III‑4.
In
addition, Council on Environmental Quality Regulations for Implementing
the National Environmental Policy Act (Section 1508.27) also require considering whether
the action may violate federal, state, or local law or requirements
imposed for the protection of the environment. For this reason,
species listed under the California Endangered Species Act or accorded
special status (i.e., considered rare or sensitive) by the California
Department of Fish and Game are included in this analysis.
Park
rare species are also included in this analysis. Park rare species are those that have no other status (either state
or federal), have extremely limited distributions in the park and
may represent relict populations from past climatic or topographic
conditions, may be at the extreme extent of their range in the park,
or represent changes in species genetics. They are included in this
analysis because they could be affected (due to proximity to human-use
zones, or susceptibility of individual plants or populations to
loss from natural or unnatural events), and their existence is considered
when evaluating consequences for any proposed management action.
The
various federal, state, and National Park Service categories for
special-status
species are defined below:
§
Federal Endangered. Any
species that is in danger of extinction throughout all or a significant
portion of its national range.
§
Federal Threatened. Any
species that is likely to become an endangered species within the
foreseeable future throughout all or a significant portion of its
national range.
§
Federal Species of Concern.
Any species that may become vulnerable to extinction on a national
level from declining population trends, limited range, and/or continuing
threats (note that this is no longer an official U.S. Fish and Wildlife
Service category, but is still considered in this document because
it contains many species that could become threatened or endangered).
§
California Endangered. Any species that is in danger of extinction throughout
all or a significant portion of its state range.
§
California Threatened. Any species that is likely to become an endangered species
within the foreseeable future throughout all or a significant portion
of its state range.
§
California Species of Special Concern. Any species that may become vulnerable
to extinction on a state level from declining population trends,
limited range, and/or continuing threats; could become threatened
or endangered.
§
California Rare (Plants Only). A native plant that, although not currently threatened
with extinction, is present in small numbers throughout its range,
such that it may become endangered if its present environment worsens.
§
Park Rare (Plants Only).
Identified by the National Park Service based upon the following
criteria:
–
Locally rare native
–
Listed by the California
Native Plant Society
–
Endemic to the park or its local vicinity
–
At the furthest extent of its range
–
Of special importance to the park
–
The subject of political concern or unusual public interest
–
Vulnerable to local population declines
–
Subject to human disturbance during critical portions of its life
cycle
Critical
Habitat
Critical
habitat for federally listed species has not been designated within
Yosemite Valley.
Species
Considered
A
total of 36 special-status
species (22 wildlife species and 14 plant species) are considered to potentially
occur in Yosemite Valley (see tables C‑1 and C‑2 in Appendix C). Species evaluated
in this section include federally listed threatened or endangered
species; species of concern (former federal Category 2 species); state-listed
threatened, endangered, and rare species; and species that are locally
rare or threatened that are known to be or could be present within
the project area. Plant species designated by the National Park
Service are also included. The species list was generated based
on data gathered from the National Park Service, U.S. Fish and Wildlife
Service, and the California Natural Diversity Data Base.
Sixty-three
species (24 species
of wildlife and 39
species of plants) that were addressed in the Final
Yosemite Valley Plan/SEIS are not
evaluated in this environmental assessment because their occurrence
in Yosemite Valley is either unlikely or
incidental. Some of these animal species are not addressed in this
document because their geographic range does not include the Valley,
their habitats do not occur in the Valley, and/or they have never
been known to occur in the Valley. These species include the Merced
Canyon shoulderband snail, Valley elderberry longhorn
beetle, Bohart’s blue butterfly, limestone salamander, mountain
yellow-legged
frog, Mount
Lyell shrew, Sierra Nevada snowshoe hare, white-tailed
hare, Sierra
Nevada mountain beaver, California wolverine, and Sierra Nevada bighorn sheep. Other animal species that formerly
occurred in the Valley but are no longer present because of either
absence of habitat or increased human disturbance despite the presence
of habitat, are great gray owl, willow flycatcher, and yellow warbler.
Sharp-shinned
hawk and long-eared owl formerly nested in Yosemite Valley, but there have been no records since the 1930s
for the hawk and since 1915 for the owl. They are not considered
resident or breeding species in the Valley.
Sierra Nevada red fox and Pacific fisher were never known
to be present in Yosemite
Valley,
but habitat for these species continues to exist in the Valley,
and these species could occur in the Valley if disturbance from
humans were much lower. Wildlife species that occur in the Valley
on an incidental basis are bald eagle, golden eagle, northern goshawk,
merlin, and prairie falcon. The Yosemite toad was recorded in Yosemite Valley, but Yosemite Valley is unusually low in elevation for this species.
It has not been observed since the initial observation, and it is
unlikely to occur in the Valley.
Special-status
plant species addressed in the Final
Yosemite Valley Plan/SEIS whose habitats or natural distribution
do not include Yosemite Valley are as follows: Tiehm’s rock-cress, Sweetwater
Mountains milkvetch, capitate sedge, alpine cerastium, Sierra claytonia,
linear collinsia, draba, desert fleabane, Congdon’s woolly sunflower,
Dane’s dwarf gentian, common juniper, Congdon’s lewisia, snow willow,
Yosemite onions, snapdragon, black and white sedge, Congdon’s sedge,
Tompkin’s sedge, Indian paintbrush, Small’s southern clarkia, Child’s
blue-eyed
Mary, golden aster, Yosemite ivesia, pitcher sage, Congdon’s monkeyflower,
slender-stemmed monkeyflower, inconspicuous monkeyflower, Palmer’s
monkeyflower, pansey monkeyflower, dwarf sandwort, Sierra sandwort,
phacelia, Bolander’s skullcap, Bolander’s clover, trillium, whitneya,
Hall’s wyethia, and groundsel.
Curry Village and East Yosemite Valley Campground Special-Status Species
Table
III‑6 lists the species that could potentially
occur in the project planning areas based on the occurrence of habitat
and the distribution of species in Yosemite Valley.
Some of the species in these tables are addressed in the Yosemite Valley Plan, except for the pale big-eared bat, which was addressed in
the Happy Isles Gauging Station
Bridge Removal Project Environmental Assessment, and three plant
species—California bollandra, varicolored hulsea, and Whitney’s
sedge. These species have been added to account for all of the species
with the potential to occur in the project planning areas. The pale
big-eared bat
is a federal species of concern and a state species of special concern.
The plant species are on Yosemite
National Park’s list
of rare species. Figure III‑4 illustrates the special-status
species that have been mapped in the project area based on the California
Natural Diversity Data Base and National Park Service geographic
information system (GIS) data.
|
Table
III-6
Project Planning Areas – Special-Status Species Expected
to Occur
|
|
Site
|
Special-Status
Species
|
|
Curry
Village
|
Special-status
animal species include: Cooper’s hawk, American peregrine
falcon, pallid bat, pale big-eared bat, Townsend’s big-eared
bat, spotted bat, small-footed myotis bat, fringed myotis
bat, long-legged bat, Yuma
myotis bat, and greater western mastiff bat.
|
|
South
Camp
|
Special-status
animal species include: Cooper’s hawk, American peregrine
falcon, California spotted owl, pallid bat, pale big-eared
bat, Townsend’s big-eared bat, spotted bat, small-footed myotis
bat, fringed myotis bat, long-legged bat, Yuma myotis bat,
and greater western mastiff bat.
|
|
Upper
Pines
|
Special-status
animal species include: western pond turtle, Cooper’s hawk,
American peregrine falcon, California spotted owl, pallid
bat, pale big-eared bat, Townsend’s big-eared bat, spotted
bat, small-footed myotis bat, fringed myotis bat, long-legged
bat, Yuma myotis bat, and greater western mastiff bat.
|
|
Lower
Pines
|
Special-status
animal species include: western pond turtle, Cooper’s hawk,
American peregrine falcon, California spotted owl, pallid
bat, pale big-eared bat, Townsend’s big-eared bat, spotted
bat, small-footed myotis bat, fringed myotis bat, long-legged
bat, Yuma myotis bat, and greater western mastiff bat.
|
|
Amphitheater
|
Special-status
bat species include: pallid bat, pale big-eared bat, Townsend’s
big-eared bat, spotted bat, small-footed myotis bat, fringed
myotis bat, long-legged bat, Yuma
myotis bat, and greater western mastiff bat. These bats could
forage over the project site.
|
|
Sources:
NPS 2000a; NPS 2000b; NPS GIS database.
|
Air Quality
To
protect the park from air quality degradation, the federal Clean
Air Act (42 United States Code 7401 et seq.) classifies Yosemite National Park as a mandatory Class I area. Class I status protects the park’s air quality
by providing the highest degree of protection, permitting only a
small amount of additional air pollution. The Clean Air Act, as
amended in 1990, requires the U.S. Environmental Protection Agency
to identify national ambient air quality standards to protect public
health and welfare and gives federal land managers the responsibility
for protecting air quality and related values from adverse air pollution
impacts. The U.S. Environmental Protection Agency has set standards
for six criteria pollutants: particulate matter less than 10 microns in
diameter (PM10), carbon monoxide, nitrogen
oxides, sulfur dioxide, ozone, and lead. An area where a standard
is exceeded more than three times in three years can be considered
a nonattainment area subject to planning and pollution control requirements
that are more stringent than for areas which meet standards.
In
addition to national standards, the California Air Resources Board
has set ambient air quality standards that are stricter than national
standards. The project area lies in Mariposa County, which currently
exceeds the national ambient standard for ozone, and state ambient
standards for ozone throughout the county and PM10 in Yosemite Valley. The Mariposa County Air Pollution
Control District is responsible for developing a State Implementation
Plan that defines control measures to bring areas in its jurisdiction,
which includes the project area, into attainment for federal and
state criteria pollutants. Basic components of a State Implementation
Plan include legal authority, an emissions inventory, an air quality
monitoring network, control strategy demonstration modeling, rules
and emission-limiting regulations, new source review provisions,
enforcement and surveillance, and other programs as necessary to
attain standards.
The
primary factors that dictate air quality in a given area are the
locations of air pollutant sources, the types and amounts of pollutants
emitted, local and regional meteorological conditions, and local
topographic features.
Existing
Sources
Air
quality in Yosemite Valley is currently affected
by internal stationary pollution sources such as furnaces, boilers,
woodstoves, campfires, and generators. Mobile sources, however,
contribute the majority of air pollution emitted within the project
area. Motor vehicle tailpipe emissions contain a variety of pollutants,
including ozone precursors, nitrogen oxides, sulfur oxides, carbon
monoxide, and reactive compounds that can lead to the formation
of particulate matter. In addition, vehicle traffic also leads to
high concentrations of PM10 associated with road dust. Other
sources within the park include construction, operations, and maintenance
activities, which often involve motor-driven
equipment and can generate significant amounts of dust.
Though
a number of pollutant sources exist within the project vicinity,
air quality in the project area is often driven by sources located
outside of the park. Sources in San Joaquin
Valley, the Sacramento
metropolitan area, and the San Francisco Bay Area include motor
vehicles, industrial sources, agricultural activities, construction
and demolition activities, prescribed fires, and a variety of other
sources.
Topography
and Meteorology
Atmospheric
conditions such as wind speed, wind direction, and air temperature
gradients interact with the physical features of the landscape to
determine the movement and dispersal of air pollutants. The state
of California is divided
into air basins that are defined partly by their meteorological
and topographical characteristics. The project area lies within
the Mountain Counties
Air Basin.
Climate throughout the Mountain
Counties Air
Basin varies substantially
with elevation and distance from the Sierra Nevada.
Summers in Yosemite Valley are warm to hot,
with occasional rain and afternoon thundershowers and high temperatures
ranging from 85 to
90 degrees Fahrenheit. Conditions during
fall and spring are highly variable and may range from dry to rainy
to snow covered, with high temperatures reaching 87
degrees and low temperatures dropping well below freezing. Winters
are generally cold, with snow accumulating throughout the Valley
in most years (Buttle and Tuttle 2003).
In
addition to its climate, the topography of Yosemite Valley,
including the Valley’s steep walls and cliff faces, influences wind
speed and direction and significantly affects temperature, rainfall,
and airflow through the Valley. Temperature variations within the
Valley further influence local airflow, dispersion, vertical mixing,
and photochemistry. These factors combine to cause shallow vertical
mixing and the formation of inversion layers that lead to high pollutant
concentrations by hindering dispersion.
While
air quality in a given air basin is usually most affected by emission
sources within the basin, the climate and topography of Yosemite
Valley combine to exacerbate air quality problems caused by pollutants
transported from upwind. The California Environmental Protection
Agency concluded that all of the ozone exceedances in 1995
in the southern portion of the Mountain
Counties Air
Basin (i.e., Tuolumne
and Mariposa Counties)
were caused by transport of ozone and ozone precursors from the
San Joaquin Valley
Air Basin
(NPS 2000a). Air
quality in the Mountain
Counties Air
Basin is also significantly
affected by pollutant transport from the metropolitan Sacramento
area and the San Francisco Bay Area.
Air
Quality Monitoring Data
Federal,
state, and local agencies operate a network of monitoring stations
throughout California
to provide data on ambient concentrations of air pollutants. Table III‑7 summarizes recent monitoring data from monitoring stations
in the project vicinity. Two of the stations that contributed data
to table III‑7 are located in Yosemite
National Park (Turtleback
Dome and Yosemite Valley
Visitor Center)
and one is located outside of the park in the Sierra
National Forest (Jerseydale).
Yosemite Valley Visitor
Center, in Yosemite
Village, and Jerseydale
are approximately 4,000 feet above sea level, and Turtleback
Dome is approximately 5,300 feet above sea level. As shown in
table III‑7, exceedances of state and national standards for ozone
and PM10
are recorded on occasion within the park and in the park vicinity.
Ozone
Ozone
is a photochemical oxidant and the primary component of smog. Ozone
is not emitted directly into the atmosphere, but is a secondary
air pollutant formed through complex chemical reactions involving
the precursor emissions of volatile organic compounds and nitrogen
oxides, both of which are emitted by stationary and mobile sources
such as motor vehicles and industrial sources. Ozone is a regional
air pollutant because it is formed downwind of volatile organic
compound and nitrogen oxide sources rather than at the source, and
significant ozone production generally requires ozone precursors
to be present in a stable atmosphere with strong sunlight for approximately
three hours.
|
Table
III-7
Recent Ozone and PM10
Concentration Data for Yosemite National
Park
and Vicinity
|
|
Pollutant
|
National
Standard
|
State
Standard
|
Monitoring
Data By Year
|
|
1997
|
1998
|
1999
|
2000
|
2001
|
|
Ozone Monitoring Data
Station: Yosemite
National
Park – Turtleback Dome
|
|
Highest
1-hour average, ppm a
|
0.12
|
0.09
|
0.11
|
0.11
|
0.10
|
0.12
|
0.11
|
|
Number of state exceedances b
|
|
|
3
|
10
|
4
|
3
|
3
|
|
Number of national exceedances
|
|
|
0
|
0
|
0
|
0
|
0
|
|
Highest
8-hour average, ppm
|
0.08
|
NA
|
0.10
|
0.10
|
0.09
|
0.10
|
0.10
|
|
Number of national exceedances
|
|
|
3
|
9
|
4
|
6
|
4
|
|
Station: Sierra
National Forest – Jerseydale (approximately 12 miles west
of Wawona)
|
|
Highest
1-hour average, ppm a
|
0.12
|
0.09
|
0.12
|
0.11
|
0.16
|
0.12
|
0.12
|
|
Number of state exceedances b
|
|
|
7
|
12
|
13
|
9
|
3
|
|
Number of national exceedances
|
|
|
0
|
0
|
1
|
0
|
0
|
|
Highest
8-hour average, ppm
|
0.08
|
NA
|
0.11
|
0.10
|
0.11
|
0.09
|
0.09
|
|
Number of national exceedances
|
|
|
7
|
14
|
21
|
14
|
7
|
|
Particulate
Matter (PM10)
Monitoring Data
Station:
Yosemite Village – Visitor Center
|
|
Highest
24-hour average, mg/m3 a
|
150
|
50
|
62
|
40
|
82
|
98
|
312
|
|
State exceedances/samples c
|
|
|
1/56
|
0/55
|
2/61
|
3/61
|
8/73
|
|
National exceedances/samples
|
|
|
0/56
|
0/55
|
0/61
|
0/61
|
1/73
|
|
Annual
geometric mean, mg/m3
|
50
|
30
|
19.6
|
18.0
|
23.5
|
22.2
|
23.8
|
|
a ppm = parts per million; mg/m3
= micrograms per cubic meter.
b For ozone, “number of exceedances” refers to
the number of days in a given year during which the standard
was exceeded.
c PM10
is usually measured every sixth day (rather than continuously
like other pollutants). For PM10, “exceedances/samples”
indicates the number of exceedances of the standard that occurred
in a given year and the total number of samples that were
taken that year.
Note:
NA = Not applicable. ND = No data available.
Sources:
California Environmental
Protection Agency, Air Resources Board, 2000, 2003
|
The
adverse health effects associated with ozone exposure primarily
pertain to the respiratory system. Scientific evidence indicates
that ambient levels of ozone not only affect sensitive receptors
but healthy adults as well. Short-term
exposure to ozone can cause constriction of the airways, increased
respiratory rates, and pulmonary resistance, and may also irritate
the eyes. In addition to causing shortness of breath, ozone can
aggravate respiratory diseases such as asthma, bronchitis, and emphysema.
Table
III‑7
shows that exceedances of state (one-hour) and national (eight-hour)
ozone standards occurred on an average of 3 to 13
days per year in the past five years for which data are available.
The data suggest that ozone exceedances occur more frequently in
Sierra National Forest than in Yosemite National Park. Exceedances of the ozone standards are a summertime
phenomenon, with most of the exceedances in July, August, and September,
and only occasional exceedances in June and October. As discussed
previously, ozone concentrations in Yosemite National Park are largely a function of pollutant transport
from San
Joaquin
Valley, Sacramento, and, to a lesser extent, the San Francisco
Bay Area.
Sensitive
Receptors
Land
uses such as schools, child care centers, hospitals, and convalescent
homes are considered to be more sensitive than the general public
to poor air quality, as the population groups associated with these
uses have increased susceptibility to respiratory distress. Residential
areas are also considered more sensitive to air quality conditions
than commercial and industrial areas, as people generally spend
longer periods of time in residential areas. Recreational uses are
considered sensitive compared to commercial and industrial areas
due to the greater exposure to ambient air associated with exercise
and outdoor activities.
Trail
and recreational users make up the majority of the sensitive receptors
in the project vicinity, along with employees living in the area.
There are no schools, child care centers, hospitals, or convalescent
homes in Yosemite Valley. Trails and recreational
facilities are described in the Visitor Experience section of this
environmental assessment. Employee housing is currently located
in the northeastern, southeastern, and northwestern corners of Curry
Village and in the North
Pines area.
Noise
Introduction
By
definition, noise is human-caused sound that is considered unpleasant and unwanted.
Whether a sound is considered unpleasant depends on the individual
who hears the sound and the setting and circumstance under which
the sound is heard. While performing certain tasks, people expect
and, as such, accept certain sounds that are considered unpleasant
under other circumstances. For example, if a person works in an
office, sounds from printers, copiers, telephones, and keyboards
are generally acceptable and not considered unduly unpleasant or
unwanted. By comparison, when resting or relaxing, these same sounds
may be intolerable.
Sounds
found desirable during times of rest and relaxation are referred
to as natural quiet and
include natural, outdoor ambient sounds without the intrusion of
human-caused
sounds. Natural sounds throughout Yosemite
National Park – including
waterfalls, flowing water, animals, and rustling leaves – are not
considered noise. The enjoyment of natural sounds along the river
contributes to the Yosemite visitor’s experience,
and natural quiet can be essential for some individuals to achieve
a feeling of peace and solitude. Noise within the park results from
human-made and mechanical sources, including
motor vehicles, generators, aircraft, and human activities such
as talking and shouting.
Noise
levels are usually measured in A-weighted
decibels (dBA), and noise descriptors such as the energy equivalent
noise level (Leq) and the day-night average noise level (Ldn) are commonly
used to account for noise fluctuations over time. Generally, a 3-dBA
increase in ambient noise levels is considered the minimum threshold
at which most people can detect a change in the noise environment;
an increase of 10 dBA is perceived as a doubling of
the ambient noise level. Ambient noise levels in Yosemite
Valley typically range from 60
to 65 dBA Ldn. As a point of
reference, a conversation between two people would typically measure
about 60 dBA, and noise above 80 dBA can cause hearing loss if prolonged.
Existing
Noise Sources
Motor
Vehicles
The
noise environment throughout the project area is primarily influenced
by motor vehicles. Noise from motor vehicles, including buses, recreational
vehicles, and transit vehicles, is obviously loudest immediately
adjacent to roadways and parking areas, but due to generally low
background sound levels can be audible at significant distances.
Atmospheric conditions such as wind, temperature, humidity, rain,
fog, and snow, along with topography and foliage, can significantly
affect the presence or absence of motor vehicle noise throughout
the project area.
Roads
and parking areas are common throughout the project area and accommodate
a steady stream of traffic throughout the area, as detailed in the
Transportation Planning section. Curry
Village is bordered to
the north by Southside Drive
and Curry Village Road
and includes approximately 650 parking spaces associated with the
lodging and service facilities. The South Camp area provides overnight
parking for 120 vehicles
in the wilderness parking area and is bordered along its northeastern
edge by Happy Isles Loop Road. The Upper Pines and Lower Pines Campgrounds
include approximately 1.5 miles of secondary roads, as well as
parking for 318 drive-in campsites. The Upper Pines area
is bordered by Happy Isles Loop Road along its southwestern and
northwestern edges. A short, secondary road spur passes to the east
of the amphitheater area to serve the campsites, employee housing,
and stable located in the North Pines area.
Aircraft
Aircraft
are a second major noise source in the project area. Approximately
55% of visitors surveyed
by the National Park Service as part of a report to Congress (NPS
1994a) reported hearing
aircraft sometime during their visit. The report notes that recognition
of noise from aircraft was highly variable from location to location
and that, as might be expected, impacts were greater when respondents
had removed themselves from automobiles and from crowded visitor
areas; a majority of the complaints came from wilderness trail users.
Measurements
made in 1993 at four
locations within the park, including Rafferty Creek, the Soda Springs
area in Tuolumne Meadows, Mirror
Lake, and Glacier Point,
indicated that aircraft were audible during 30 to 60%
of each measurement period. Most overflights are associated with
high-altitude jet aircraft. The National
Park Service sometimes uses aircraft in its management activities,
primarily consisting of helicopters for firefighting, search and
rescue, emergency medical response, law enforcement, and other special
operations (NPS 1993c).
Other
Sources
Other
mechanical sources of noise within the park and near the Curry
Village and east Yosemite
Valley campground areas include generators, radios,
concession operations, heating and air conditioning units, park
maintenance activities and equipment, and road construction equipment.
The frequency of use and the location of maintenance equipment and
visitor-related mechanical sources vary
both by season and reason for use. In addition to mechanical noises,
Curry Village
also experiences high levels of noise associated with employee housing
and guest lodging, including normal social activities among residents,
the sounds of household appliances, and other outdoor tasks. Nonmechanical
noises in the Upper and Lower Pines areas include similar noises
associated with camping, outdoor recreation, and social activities.
Ambient
Sound/Noise Levels
Current
ambient noise levels in the project area vary by season, location,
and the number of park visitors. Ambient noise levels throughout
Yosemite Valley typically range from 60 to 65
dBA Ldn, though the existing noise environment changes
dramatically throughout the year in direct proportion to the level
of park use, with summer noise levels generally being higher than
winter levels. Changes are due primarily to the number of cars and
buses traveling though the Valley and the amount of visitor-related
noise.
To
determine the winter ambient noise level, 24-hour
A-weighted statistical
noise surveys were performed at 10
locations throughout the park in February 1999.
Measurements at Stoneman Meadow, directly north of Curry
Village and east of Lower
Pines, showed a daytime and nighttime noise level average of 59 dBA at a distance of 100
feet from Southside Drive
(NPS 2000b). Additional
real-time noise measurements taken in
Curry Village
showed instantaneous ambient levels in the range of 63
to 69 dBA, depending
on the level of human activity in the area. Sound levels within
the Upper Pines Campground ranged from 32
dBA in the early morning, when human activity levels were at the
lowest, to 55 dBA in late afternoon (NPS 2000b).
Ambient
noise levels in areas near roadways, particularly Southside
Drive and Curry
Village Road, are dominated by noise
from motor vehicles. Southside Drive
from Sentinel Bridge
to Curry Village
experiences approximately 4 noticeable and 10 less noticeable sound events per hour
(NPS 2000b). Ambient
noise levels in Curry
Village are typically
around 40 dBA, similar
to lower-limit
ambient sounds associated with an urban setting, although resident
conversations and the sounds of air conditioning and other appliances
can cause levels to reach 60
dBA (NPS 2000a). Background noise in larger drive-in
camping areas, including talking and laughing, sounds of water-related
recreation, pets, electric generators, radios, and stereos, are
typically between 55
and 60 dBA, but may reach 90 dBA in direct proximity to a two-cycle generator engine (NPS 2000b). Typical background noise rarely
reaches this level, however, and peak noise levels occur only between
mid-morning and
9:00 p.m.
Sensitive
Receptors
Some
land uses are considered more sensitive to ambient noise levels
than others due to their associated activities and degree of noise
exposure, including both exposure duration and insulation from noise.
Residences, hotels and motels, schools, libraries, churches, hospitals,
and parks and other outdoor recreation areas are generally more
sensitive to noise than commercial and industrial land uses.
Sensitive
receptors in the project area include local residents, overnight
visitors, and trail and recreation users. Curry
Village includes 627 units of visitor lodging, including
Stoneman Lodge, cabins, and tent cabins, and provides housing for
a number of park employees. Sensitive receptors in the Upper Pines,
Lower Pines, and South Camp areas include campers and recreation
users. In addition, the amphitheater area is adjacent to camping
areas and trails frequented by recreation users.
Regulatory
Standards
Generally,
the federal government sets standards for transportation-related
noise sources that are closely linked to interstate commerce, such
as aircraft, locomotives, and trucks; for those noise sources, state
governments are preempted from establishing more stringent standards.
State governments set noise standards for transportation-related
noise sources that are not preempted from federal regulation, such
as automobiles, light trucks, and motorcycles. Noise sources associated
with industrial, commercial, and construction activities are generally
subject to local control through noise-related
plans and policies.
Cultural Resources
Overview of Human
Occupation
American Indians
Yosemite
Valley includes evidence of thousands of years of human
occupation, reflected in the large number of archeological sites.
The National Park Service has evidence of American Indian habitation
in the Yosemite area between 4,000
and 6,000 years ago. Some preliminary evidence from the El Portal
area indicates that people may have been living there as long as
9,500
years ago. These hundreds of archeological sites, evincing thousands
of years of occupation, have contributed evidence of technological
change through time, a highly developed trade network, at least
one population replacement, and significant environmental manipulation
through the use of fire.
When
Euro-Americans
first entered Yosemite Valley in the early
1850s, the American Indians living there
were primarily Southern Sierra Miwok, with individuals joining or
visiting them from the Mono Lake Paiute, and Central Sierra Miwok
band, coupled with some individuals from the disbanded missions
(post 1820s). The upland areas of the Merced River
drainage were frequented by Southern Sierra Miwok and the Mono Lake
Paiute, and at least traversed by Western Monos and possibly Chukchansi
Yokuts.
The
Mariposa Indian War of 1851 was triggered by the influx of Euro-American miners, ranchers, farmers,
and merchants who had been taking American Indian lands since 1848. After 1851, as awareness of Yosemite Valley
grew, hotels and other travel-related
amenities were developed. Due to the development of hotels and tourist-related activities, additional Mono
Lake Paiutes arrived and remained in Yosemite Valley
as part of the workforce. Management of the Yosemite
Valley was directed by Euro-American
institutions, and American Indian interests were subject to decisions
made without their influence. Traditions changed as Indian people
built nontraditional houses, vacated old village sites, and built
new villages. These changes were due in part to efforts by Euro-Americans
to centralize the Indian people as a tourist attraction and control
their activities.
American
Indian people continue to live in and around the park, and many
are employed by the National Park Service, the concessioners, or
other local businesses. At least seven Indian tribes claim traditional
associations with Yosemite
National Park, and the
National Park Service has entered into various agreements with the
American Indian Council of Mariposa County, Inc., the political
organization representing the Southern Sierra Miwok Tribe. Individuals
from most of these tribes continue to maintain cultural associations
with lands and resources in Yosemite
National Park through
traditional ceremonies, gathering of traditional plants, and other
activities.
Euro-Americans
The
first Euro-Americans
to enter the Yosemite region were a party
of hunters and trappers, led by Joseph R. Walker, who made an east-west crossing of the Sierra Nevada
in October 1833.
Probably following a portion of the old Mono Indian Trail along
the crest between the Merced
and Tuolumne Rivers,
the expedition passed through what is now Yosemite
National Park. It is
not known whether the party viewed the Yosemite Valley.
In
October 1849, William
Penn Abrams, while tracking a grizzly bear from Savage’s Trading
Post (at the junction of the Merced River and the South Fork approximately
10 miles from the park’s western
boundary), described his first view of what was unquestionably the
Yosemite Valley. Although Abrams made no mention of American Indians,
Chief Tenaya and his people were residing in the region at the time.
With
the advent of the Gold Rush, parties of miners began traversing
every river, stream, and drainage in the Sierra Nevada
foothills, and many made their way up the Merced River
to the Yosemite Valley, where they encountered
American Indians in their villages. The expedition of the Mariposa
Battalions of 1850
and 1851, intended to exterminate the American
Indians, was touted as the first expedition into the Yosemite
Valley. Two years later, Lt. Tredwell Moore, on a punitive
expedition against Chief Tenaya and his band of Yosemite Miwok,
made the first documented visit to Yosemite Valley
over the Mono Trail.
Archeological
Resources
The
area of potential effect contains a myriad of archeological, ethnographic,
and cultural landscape resources, including historic archeological
sites. All of the archeological resources are part of the Yosemite
Valley Archeological District, which is included in the National
Register of Historic Places. These resources consist of prehistoric
sites, some of which are the archeological remains of ethnographic
villages and historic archeological resources, including the Camp
Curry dump; the original
foundations of the LeConte Memorial Lodge, moved from Curry
Village in 1919; and subsurface refuse disposal features reflecting
historic operations of Curry
Village.
Curry
Village and the east
Yosemite Valley campground areas have been
the subject of mitigation studies and monitoring activities. Inventories
by Napton et al. (1974),
Hull and Kelly (1995),
and Hull et al. (1995)
built upon the original studies by the University
of California Archaeological Survey,
reported and summarized by Bennyhoff (1956).
These investigations have been supplemented by small, project-driven surveys and monitoring activities conducted
by National Park Service personnel and various contractors. In most
cases, the inventories have been conducted in support of park development
projects as part of the environmental and historic preservation
compliance processes. A recent comprehensive overview of archeological
resources and their information value is presented in An
Archeological Synthesis and Research Design for Yosemite National
Park, California (Hull and Moratto 1999).
This document summarizes the results of past archeological research
and presents research questions and methodologies for furthering
the understanding of prehistoric and historic lifeways in the Yosemite
region.
In
general, archeological sites are important for the information they
can provide regarding prehistoric and historic lifeways. Prehistoric
and historic American Indian sites are important to Indian people
as a tangible link with their past. In Yosemite
they generally contain some of the following: flaked and ground
stone tools, waste from tool manufacturing, food processing features,
fire hearths, structural remains, human burials, and rock art. Historic
archeological sites provide important information not available
in written records, such as construction techniques, lifestyle of
early settlers, trade and procurement of goods and materials, and
interactions with native peoples. Historic sites include structural
remains, waste dumps, work camps, and remains of industrial activities
such as logging and mining.
Historic
remains are associated with the turn of the century operations of
Curry Village
and with miscellaneous artifacts that cannot be directly linked
to a particular event or time period. Prehistoric components consist
of the archeological remains of an ethnographic village site, milling
features, and flaked stone distributions. Details about these sites
are presented later in this section.
Prehistoric
CA-MRP-84,
the suspected location of the historic village Toolahkahmah, was first visited by Bennyhoff in 1952. Even though Merriam’s (1917) description of the area is very
specific, no prehistoric cultural materials were observed, leading
Bennyhoff (1956) to conclude that the site had been
destroyed. Additional surface inspection by Napton et al. (1974) also failed to detect the presence
of a cultural deposit. Subsequent auguring conducted in the orchard
just north of the parking area in 1987
(Hull et al. 1995)
also failed to identify a cultural deposit. While several historic
and modern developments, including the orchard planted by James
C. Lamon in 1859 (Russell 1992),
paving, and construction of a reservation office, may have obliterated
any archeological evidence, it is possible that sites CA-MRP-827/H and CA-MRP-1530/H may represent the remnants of
Toolahkahmah, with the possibility of additional
constituents located beyond the limits of subsurface testing that
has been conducted to date.
A
small site (CA-MRP-186)
consisting of two milling features was originally recorded in the
1950s by the University
of California Archaeological Society
(Bennyhoff 1956),
with subsequent revisits (Rasson 1966;
Napton et al. 1974;
Mundy et al. 1986).
Auger testing was conducted in 1987
(Hull et al. 1995) in the northern and central portions
of the site. While Napton et al. had observed obsidian flaked stone
in 1974, no other
constituents were observed on the surface or during subsurface testing
or monitoring for installation of underground utilities, prompting
Hull et al. (1995) to recommend against site management,
as the site did not appear to be a contributing element of the Yosemite
Valley Archeological District.
A
light distribution of obsidian flaked stone (CA-MRP-15) situated in the vicinity of the Upper
Pines Campground was documented by National Park Service personnel
in 1986. No additional investigations have
taken place at this locale, which may have been partially affected
by construction of a sewer line. Because of dense pine-needle cover, the site limits are most likely incompletely
defined.
Also
situated in the Upper Pines Campground is a relatively large site
(CA-MRP-80)
consisting of flaked stone debitage and at least five milling features.
While the site has been visited on several occasions (Bennyhoff
1956; Napton et al. 1974; Mundy et al. 1986), no subsurface testing has been
conducted. Dense pine-needle
debris spread over a large portion of the site may be obscuring
additional constituents. Recreation use coupled with campground
facilities construction may have affected at least a portion of
the archeological remains.
CA-MRP-45/326 is suspected to be the archeological
remains of the ethnographic village site Hookehahtchke, a summer camp located on the north side of the Merced
River. The village was occupied until about 1897 and appears to be the locale described
by Lafayette Bunnell in 1851
(Hall 1929, in Bibby
1994). Constituents consisting of two
boulder milling features and a light distribution of obsidian flaked
stone are situated along the north bank of the Merced River, in
an area of high visitor usage, as indicated by three asphalt paths
that bisect the site.
Historic
Archeology
Three
historic archeological resources, all consisting of refuse deposits,
are located within the project area. CA-MRP-747H, located within the historic district,
consists of buried features containing burned and unburned butchered
bone, ceramics, hole-in-top can fragments, and bottle glass.
Ceramics indicate that the refuse dates to the turn of the century.
The presence of Dresden china and Burgess and Company china suggests
that at least a portion of the assemblage could be related to refuse
generated by the Curry
Village cafeteria. A
second refuse deposit (CA-MRP-1541H),
situated adjacent to the Curry Village Historic District, is dominated
by fragmentary metal, glass, ceramics, asphalt, concrete, wood,
faunal bone, and brick. While the artifacts may date to 1916
(Keefe 1988), historic
information confirming this early date is lacking. Information suggests
that, beginning in the 1950s,
the area served as a transfer point where refuse was stored and
sorted by type for disposal at another location. The operation was
abandoned in the late 1970s, and fill was used to cap the deposit
and restore the area to a parking lot. A contradictory account suggests
that the deposit may be up to 50
feet in depth, indicating the potential presence of buried intact
cultural deposits (Keefe 1988).
Additional
resources could be discovered in subsurface contexts, including,
for example, the remains of a cabin constructed by an early settler,
Etienne Manet, presumably where the current orchard parking is located.
Also, historical documentation suggests that stables of the Yosemite
Stage and Turnpike Company and the Yosemite Transportation Company
predating 1892 were located between the present-day Upper and Lower Pines Campgrounds
(Land and Associates 1994).
Multicomponent
The
remaining three resources in the area of potential effect consist
of both historic and prehistoric artifacts. The first site (CA-MRP-825/H), situated along the south side
of the Merced River, contains a light distribution of obsidian flaked
stone artifacts from American Indian occupation and evidence of
historic usage represented by the presence of ceramics and glass
fragments, wire nails, and miscellaneous metal items (Hull et al.
1995). The depth
of the cultural deposit was found to extend up to 27.5
inches below ground surface; however, based upon a lack of integrity,
Hull et al. (1995)
recommended that the site was not eligible for inclusion on the
National Register.
The
second multicomponent site (CA-MRP-827/H) is loosely associated with the
well-documented
ethnographic village of
Toolahkahmah.
It consists of a light distribution of flaked stone artifacts and
a historic assemblage of glass and ceramic fragments. No subsurface
examination at CA-MRP-827/H has been conducted.
Archeological
monitoring of 500 feet of trench for a gas pipeline indicated the presence
of two distinct loci of flaked stone debitage and tools and widely
distributed historic artifacts (CA-MRP-1530/H).
A lack of horizontal patterning suggests that historic-era artifacts were most likely deposited during maintenance
and usage of tent cabins. Examination of the trench profile indicated
the presence of a 2-inch-thick carbonized deposit between 8 and 14
inches below the surface. However, since no artifacts were visible
in the side walls of the trench, it could not be determined if this
site contains cultural deposits (Chick 2000).
Ethnographic
Resources
American
Indian people continue their traditional cultural associations with
Yosemite National
Park and its resources. While a limited
amount of formal research has been conducted to inventory and document
traditional resources important to Indian people, ethnohistory studies
focusing on Yosemite Valley and El Portal
have been conducted. Studies documenting cultural associations are
also underway for both the northern and southern portions of the
park, which will likely yield new information about traditional
places. A parkwide ethnographic overview was prepared during the
1970s, but will be revised based on this
forthcoming information.
The
National Park Service consults with American Indian people about
management of parklands, especially regarding the nature of the
undertakings and potential impacts to park resources. Some of the
primary concerns are access to park areas; gathering of plant materials
for food, medicinal, and utilitarian purposes; protection of archeological
and burial sites; and interpretation of Indian culture and prehistoric
and historic lifeways. The National Park Service is required to
consult on the basis of government-to-government
relations with federally recognized Indian tribes, and on a more
informal basis with nonfederally recognized tribes. The National
Park Service has entered into an agreement with the American Indian
Council of Mariposa County, Inc. for the purposes of protecting
traditional practices and establishing an Indian cultural center
at the site of the last historic Indian village in Yosemite
Valley, west of Camp 4
(Sunnyside Campground). The National Park Service is working with
park-associated American Indian groups
to develop a plan consistent with the Native American Graves Protection
and Repatriation Act to deal with inadvertent discoveries of human
remains and funerary objects.
Ethnographic
Sites and Gathering Locales
Three
ethnographic (prehistoric/historic) village sites and four associated
gathering locales are situated within or partially within the area
of potential effect. They form a mosaic of American Indian use extending
from prehistoric to historic times within the east end of Yosemite
Valley. As related by American Indian informants, Meriam (1917) describes these seven resources
as being located either on the “north/inside/land/grizzly bear side”
or on the “south/outside/water/coyote side” of the Merced
River.
The
location of Ummataw is
substantiated by the presence of archeological deposits, and as
such is considered an especially important resource. In 1911,
Merrian wrote in his journal, “I got him to show me the site of
the old Indian village called Um’ma-taw.
On a high sandy place in the pine woods between Happy Isles
and Camp Curry,
on the north side of the wagon road” (Field 1911,
in Bibby 1994). As
mentioned above, several surface and subsurface studies have failed
to locate archeological deposits at the presumed location of Toolahkahmah,
and it may be that CA-MRP-827/H
and CA-MRP-1530/H
represent portions of this village. Hookehahtchke,
a summer camp located on the north side of the Merced River, was
apparently occupied until about 1897
and appears to have also been described by Lafayette Bunnell in
1851 (Hall 1929, in Bibby 1994).
Although surface archeological remains have not been identified
and subsurface investigations have not been conducted at the exact
location of this later village, Bibby (1994)
suggests that CA‑MRP-45 may
be associated with this locale. Interviews with American Indian
informants (Bibby 1994)
indicate that gathering areas in the project vicinity were sources
of mushrooms and other fungi, and that these areas were used during
the historic era as well as the prehistoric past.
Cultural
Landscape, Historic Sites and Structures
Cultural
landscapes are the result of the long interaction between people
and the land, and the influence of human beliefs and actions over
time upon the natural landscape. Shaped through time by historical
land use and management practices as well as politics, property
laws, technology, and economic conditions, cultural landscapes provide
a living record of an area’s past, a visual chronicle of its history.
The dynamic nature of modern human life contributes to the continual
reshaping of cultural landscapes, making them a good source of information
about specific times and places, but at the same time rendering
their long-term
preservation a challenge.
The
geophysical characteristics of Yosemite Valley
have shaped patterns of human use since the earliest days of Indian
settlement. As a result, the Valley’s cultural landscape is significant
for its archeology, its role in the exploration and settlement of
the west, architecture, art, landscape architecture, recreation,
and conservation. The Valley’s cultural landscape encompasses cliff
walls, meadows, the river and streams, as well as roads, trails,
and buildings.
Many
historic sites and structures within Yosemite Valley
have been singled out for their significance and are either National
Historic Landmarks or are listed in the National Register of Historic
Places. Historic resources in Yosemite
National Park were identified
and evaluated in the Cultural
Resources Management Plan (NPS 1979)
and in the 1979 memorandum
of agreement among the California State Historic Preservation Officer,
the National Park Service, and the Advisory Council on Historic
Preservation, and its accompanying correspondence. A subsequent
Historic Resources Study
(NPS 1987) and other
project-specific
reports identified and evaluated structures and sites not addressed
in those earlier documents.
There
are no individually designated National Historic Landmarks in the
project area. The Draft National Register Nomination for the
Yosemite Valley Historic District (NPS 2002) includes, as contributing resources,
all the buildings of the Camp Curry (Curry Village) Historic District, listed in 1978
and amended in 1979, as well as several additional structures
within Curry
Village and several others outside Curry Village’s district boundary. The period of significance
for the Yosemite Valley Historic District covers the period from
Indian settlement to 1945. The Camp Curry Historic District
includes the Tresidder Residence, Mother Curry Bungalow, the original
registration building, several bungalow units, and 556
canvas tent cabins. The camp itself dates from 1899, with changes
and additions through the early 1920s. The tent cabins constitute the
most significant and intact tent cabin complex left in the National
Park System. This district also retains a number of contributing
features that reflect the original development of this area as a
rustic lodging complex. Within Curry Village, there are 111 contributing
buildings and 561 contributing structures from the
period of significance. There are also three contributing sites,
two within Curry Village (the remains of the original LeConte Memorial
Lodge and the Curry Orchard parking area) and one outside the Curry Village boundary (Stoneman Meadow). These sites are
analyzed in other sections of this document.
The
overall pattern of development for the Curry Village area remains as it was at the end of the historic
period. The character of the historic village has been compromised
by excessive planting in some areas, but its informal rustic character
remains. The buildings retain their historic placement and physical
appearance. Some original buildings have been lost and a number
of structures have been added, most notably the central Pavilion
in Curry Village, a large dining facility built in the 1970s
after the original building was destroyed by fire.
Social Resources
Scenic Resources
The
project area is well known for its magnificent scenic views. Important
scenic features include high peaks, sheer cliffs, massive granite
domes, waterfalls, expansive wilderness, and giant sequoias. The
Draft National
Register Nomination for the Yosemite Valley Historic District identified
11 “quintessential
features” of the Valley, with 11
sets of views of these features that “contribute to defining the
character of the cultural landscape in Yosemite Valley.”
None of the 11 primary views are within the project
area. The significant scenic features in Yosemite Valley
include Half Dome, Yosemite
Falls, El
Capitan, Bridalveil Fall, Three Brothers, Cathedral
Rocks and Spires, Sentinel Rock, Glacier
Point, North Dome, Washington Column, and Royal Arches. The landscape
features most visitors look for and are able to distinguish are
Glacier Point, North Dome, and Washington Column (NPS 2000a).
Visual
analyses conducted by the National Park Service evaluated all points
from which the 11
features could be seen and identified the areas in Yosemite Valley
that were consistently selected by eminent historic photographers
and painters as the best areas for photographing and painting scenic
features. Based on this analysis, locations in the Yosemite
Valley were classified as A‑scenic
(viewpoints most commonly selected by eminent photographers and
painters), B‑scenic (points less commonly
selected), or C‑scenic
(areas of minor scenic quality). Generally, lands along with the
Merced River and meadows (such as Stoneman
Meadow) throughout Yosemite Valley were classified
as highly scenic. The percentages of project area lands within each
scenic classification are indicated in table III‑8. Over 70%
of the project area is classified as either A‑scenic
or B‑scenic.
A small area (1.7%) was not rated for scenic quality because it represents
the steep sloping sides of the Valley. Figure III‑5 illustrates the locations of the scenic
classifications applicable to the project area.
Views
of dramatic geological formations, waterfalls, meadows, and the
Merced River are possible from numerous points
throughout Yosemite (NPS 1994c). Viewpoints include the Northside/Southside
Drive loop road, trails, overlooks, designated
vista points/turnouts, and parking areas along the roads. At the
western entrance to the project area, the North Dome/Washington
Column vista point provides a view to those features located along
the north canyon wall. From the eastern section of the road at Curry
Village, there are views
of Stoneman Meadow, Royal Arches, and Glacier Point. The Half Dome
vista point is located near the eastern edge of Curry
Village and at the new
amphitheater site (figure III‑6).
The
Merced River is a major visual element in
the project area. As identified in the Merced River Plan, magnificent
views are available from the river and its banks of waterfalls (Nevada,
Vernal, Illilouette, Yosemite, Sentinel,
Ribbon, Bridalveil, and Silver Strand), rock cliffs (Half Dome,
North Dome/Washington Column, Glacier Point, Yosemite Point/Lost
Arrow Spire, Sentinel Rock, Three Brothers, Cathedral Rock, and
El Capitan), and meadows (Stoneman, Ahwahnee, Cook’s, Sentinel,
Leidig, El Capitan, and Bridalveil).
The
Merced River winds mainly along the eastern
and northern border of the project area. This highly scenic river
contributes substantially to Yosemite Valley
and the project area’s scenic value. The banks of the river are
lined with boulders and trees, along with other vegetation of varying
size and density. The Merced River varies with the seasons; in spring,
the river changes from calm, clear, and green to white and frothy,
as series of riffles interrupt more calm sections both upstream
and downstream of the project area. Tenaya Creek converges with
the Merced River just north of the Lower
Pines Campground. It has many of the same characteristics as the
Merced River, yet is much smaller and less
visually dominant. This smaller creek connects with the Merced
River just north of the Lower Pines redevelopment area.
Curry Village and East Yosemite Valley Campgrounds Scenic Quality
Curry Village
Curry
Village is one of the
major tourist destinations in Yosemite
National Park. It is
a densely developed area of guest accommodations as well as employee
housing. It also
includes
a grocery store, dining facilities, an amphitheater, and swimming
pool, and serves as the base for numerous recreational activities,
such as rafting, bicycling, and mountaineering. Its concentrated
development contrasts with the more natural feel of the surrounding
undeveloped areas, such as Stoneman Meadow to the north and the
steep rocky hillsides to the south.
As
indicated in the Yosemite
Valley Cultural Landscape Report, “… views are not a prominent
feature of the Curry Village
study area. Its woodland setting generally imparts an inward orientation,
although from open areas, such as the large parking lots northeast
of the visitor services complex, and the ice skating rink, it is
possible to view Half Dome, Tenaya Canyon, and the Granite Cliffs
of the north and south canyon walls” (NPS 1994c).
The main development of Curry
Village, about 73.4% of the Village area, is located south of Southside
Drive and Curry
Village Road and is classified as B‑scenic. Stoneman Meadow and the Curry Orchard,
on the north side of Curry Village Road,
occupy approximately 22.6% of the Village area, and are classified
as A‑scenic.
The remaining 4%
of Curry Village
is the steep slope of the southern Valley hillside and is not rated
in the National Park Service rating system.
Within
Curry Village,
there are views that are significant in the context of the historic
district. These include the views looking east and west along the
unpaved pedestrian pathways that meander through the tent cabin
area, with its densely placed, white structures interspersed with
large boulders under a canopy of mature pines. Similarly, characteristic
views are available to the east and west through the bungalow area,
where the rustic wood cabins are set irregularly in a deeply forested
setting.
Views
both north and south across the central common area of Curry
Village present contrasting
scenic qualities. The view south is comprised of the historic Camp
Curry sign in the foreground, several of the Village’s contributing
buildings in the middleground, the wooded slope beyond, and the
steep rock face rising up to Glacier Point as background. Looking
toward the north, the view is over the common area and the historic
sign, across Stoneman Meadow, to the southern cliffs of the Valley.
The views in both directions are somewhat restricted due to the
overgrowth of vegetation introduced into the common area.
Amphitheater at Clark’s Bridge
The
0.91-acre
amphitheater area is located north of Happy Isles Loop Road, just
east of the Merced River and Clark’s Bridge. The site is immediately south of
the horse stable and associated facilities and east of the Lamon
Orchard. A trail runs through this area and a campground access
road is located to the west, providing numerous viewing opportunities.
Minimal screening between Happy Isles Loop Road and the amphitheater
site enables unrestricted views from vehicles along the road. The
Merced
River
is visible to the southwest of this location. The amphitheater area
is designated B‑scenic.
Much of the area surrounding the amphitheater site is sparsely wooded,
which provides visitors at the site with some distant views, although
limited by the nearby thick woodlands.
South Camp
South Camp is located east of Curry Village adjacent
to Upper Pines Campground, on the west side of the Happy Isles Loop
Road. The vast majority of South Camp is forested, with the exception
of a 1.7-acre opening used for equestrian purposes. The Happy
Isles Loop Road borders South Camp for 0.3
miles, providing drivers with a view of this forested area. The
northern portion of South Camp is rated as B‑scenic, while the southern and eastern areas
are designated C‑scenic.
A total of 5.33 acres (51%)
of South Camp are B‑scenic, while the remaining
5.13
acres (49%) are rated as C‑scenic. The majority of the
South Camp area is undeveloped natural forest, which provides high-quality
foreground views for travelers along Happy Isles Loop Road and hikers
along the trail parallel to the road. Middleground and background
views are limited by the forest cover.
Upper
Pines Campground
Upper
Pines, located on the eastern side of the Happy Isles Loop Road,
contains auto/recreational vehicle campgrounds and associated parking
areas. The camping area is accessed from the northern section of
the Happy Isles Loop Road, west of Clark’s
Bridge. The Upper Pines Campground area is primarily forested, interspersed
with small unvegetated areas. Two small creeks run through and along
the eastern edge of the campground area. These small water features,
combined with the Merced River to the east,
provide a high-quality
visual element in the immediate landscape. The flat topography and
tree cover limit middleground and background views. Upper Pines
is designated as B‑scenic and C‑scenic. The southeastern 61.2%
of the Upper Pines site is classified C‑scenic
because of the restricted views, while the north and northwestern
38.8%
of the site is rated as B‑scenic,
due to the somewhat distant views that are possible from this portion
of the site.
Lower
Pines Campground
Lower
Pines consists of an automobile/recreational vehicle campground
and associated parking area located directly east of Stoneman Meadow
and west of the Merced River. Stoneman Meadow
is a highly scenic area to the west, while the Merced
River provides high-quality
views to the east. This development area has thick vegetation to
the west, especially along the edge of Stoneman Meadow, although
the forest thins to the east toward the Merced River.
The Lower Pines area is designated A‑scenic and B‑scenic. The northern 4.9-acre portion of the Lower Pines
site is designated A‑scenic
(45.8%). The remaining 5.8 acres are classified B‑scenic (54.2%).
Extended views of the area are available to campers and hikers walking
by Lower Pines. Drivers on Happy Isles Loop Road have a partial,
short-duration view of the Lower Pines
Campground area.
Park Operations and Facilities
Various
divisions of the National Park Service manage park operations and
public utilities within the Yosemite Valley.
The four branches of the Division of Facilities Management – Buildings
and Grounds, Roads and Trails, Utilities, and Design and Engineering
Professional Services – manage the park’s utilities and its solid
waste and recycling and are responsible for maintenance and repair
of all National Park Service–owned facilities. The Utilities branch
performs power management; water supply, treatment, and infrastructure;
and wastewater removal, treatment, and infrastructure. The Roads
and Trails branch performs road and trail maintenance and construction
and solid waste and recycling services. The Buildings and Grounds
branch performs buildings and grounds management, including campsite
maintenance.
As
shown in figure III‑7, the project area is serviced by a
network of roads, electric lines, water lines, and sewer lines.
Transportation infrastructure in the project area includes primary
roads, secondary roads, parking areas, and a network of pedestrian,
hiker/stock, and multi-use trails. Southside
Drive and Curry
Village Road follow the northern edge
of Curry Village,
and a number of smaller roads and parking areas run throughout the
area. Approximately four miles of secondary loop roads and a number
of parking areas accommodate drive-in and walk-in campers in the Upper Pines and
Lower Pines campgrounds and the North Pines Campground, northeast
of the amphitheater. Happy Isles Loop Road
runs between Upper and Lower Pines campgrounds and between Upper
Pines Campground and South Camp.
A
larger parking area serves wilderness users and campers in the South
Camp area. This parking area is the site of a former waste accumulation
area, which is under evaluation as a separate project. This area
is not expected to extend into the area planned for the new South
Camp. Should later investigations associated with the waste accumulation
area indicate that remediation is needed in or adjacent to any campsites,
this would either be accomplished prior to their development, or
the affected campsites would not be open for public use during remediation
activities.
Project
area utilities include electric, water, and wastewater lines. Electricity
is purchased by the National Park Service from the Pacific Gas and
Electric Company, then distributed and resold to end users throughout
Yosemite Valley. Power is delivered to Curry
Village, Upper and Lower
Pines, and South Camp from the substation at Yosemite
Village via transmission
lines along Northside Drive,
Southside Drive,
Curry Village Road,
and Happy Isles Loop Road. In addition, the amphitheater is served
by a second transmission line that passes through the North Pines
area. From the transmission lines, a complex network of distribution
lines carries power from the transmission lines to end users throughout
the project area.
The
National Park Service produces the Valley’s water supply. Water
is produced and chlorinated at the three wells located near Yosemite
Lodge and pumped to a 2.5-million-gallon storage tank at Happy Isles.
Drinking water is then distributed to the project area via water
lines entering the project area from Happy Isles. Upper and Lower
Pines are bisected by water mains entering from the southeast, with
short spur lines delivering water to sources throughout the area.
A second main, branching to the north near the southeastern corner
of Lower Pines, delivers
water to the Lower Pines and amphitheater users. Another water main
follows Happy Isles Loop Road between South Camp and Upper Pines,
then follows North Side Drive north of Curry
Village. Two water lines
pass through the northern portion of Curry
Village, with several
spurs delivering water to employee housing and visitor lodging areas.
The amphitheater area is served by a water line extending from the
south end of Lower Pines to the western edge of the amphitheater,
then north past the stable area.
In
addition to water lines, sewer lines service all areas except the
amphitheater. Sewer lines parallel the water lines from the southeast
corner of the project area through the length of the Upper and Lower
Pines areas, with short spur lines leading to bathroom facilities.
The sewer lines closest to South Camp are the short spur lines that
branch west from the line passing through Upper Pines. A separate
line passes from Northside Drive to Curry Village Road and on through
Curry Village, branching to serve both the visitor lodging areas
in the eastern portion of the Village and employee housing in the
western portion. A third sewer line serves the North Pines camping
area and exits the project area directly north of Lower Pines. Its
northernmost branch ends in the western corner of the Tenaya area,
and its southernmost branch ends approximately 500
feet northeast of the amphitheater.
Solid
waste and recycling collection and removal are carried out by the
Roads and Trails Branch of the National Park Service Division of
Facilities Management. Yosemite Concession Services is responsible
for collecting solid waste and recyclable materials from lodges,
restaurants, and employee housing, while the Roads and Trails branch
is responsible for public areas such as campgrounds, picnic areas,
and National Park Service employee housing (Kies 2003).
Trash and recycling bins are located at existing
facilities and recreation areas throughout the project area and
are emptied daily. Solid waste is carried to the back loading dock
at Curry Village for
transport by a private contractor, Total Waste Systems, to the Mariposa County landfill.
Recyclable materials are delivered to a central processing station
in Yosemite Village, where
they are processed before being removed and marketed by Total Waste
Systems. In addition, there is a public recycling center in Curry Village where
individuals may redeem California redemption
beverage containers and drop off other glass, aluminum, plastic,
and paper recyclables (Kies 2003).
Transportation
Planning
Private
or rental vehicles and chartered tour buses are the major modes
of transportation both to and through the park. Most visitors to
Yosemite travel by private vehicle, but tour
buses accommodate a significant percentage of visitors (table III‑9). In addition, a small number of visitors use regional
transit buses operated by VIA Adventures, Inc./Grayline of Yosemite
and the Yosemite Area Regional Transportation System.
|
Table
III-9
1998 Travel Modes of Visitors Entering Yosemite Valley
|
|
Description
|
August
Daily Average
|
|
Total
number of visitors
|
13,742
|
|
Number
of tour bus passengers
|
1,673
|
|
Percentage
of visitors traveling by bus
|
12%
|
|
Total
number of vehicles
|
4,184
|
|
Numbers
of buses entering
|
63
|
|
Percentage
of buses compared to all vehicles
|
1.5%
|
|
Source:
NPS 1998c
|
The
highways that lead into Yosemite become the
internal parkwide road system at the entrance stations (except for
Highway 140). There
are no State of California
highways within park boundaries; however, state route numbers are
used on park signs to orient visitors. The roadways throughout Yosemite
National Park are classified
by the National Park Service as follows (see figure III‑8):
§
Primary roads and state highways, always paved, generally open to
the public all year
§
Secondary roads, always paved, generally open to the public all
year
§
Campground and campground loops
§
Minor roads, unpaved or paved-but-rough,
generally open to the public during summer months
§
Administrative roads, open and not open to the public
§
U.S. Forest Service roads, generally dirt, possibly four-wheel
drive
§
Residential roads
§
Miscellaneous (turnouts, parking lots, service roads, etc.)
The
primary roadways in Yosemite Valley are paved
with asphalt and have two travel lanes and a pavement width of 21 feet. Portions of the roadway system
can be confusing to first-time
visitors because of the frequent one-way
circulation and limited opportunities to cross the Merced
River. High traffic volumes within Yosemite
Valley, along with inadequate parking and visitor confusion,
can create congestion during the peak season. Excess vehicle circulation
is common, as visitors seek the best routes for their destination
and search for limited parking spaces. Excess vehicle circulation
and congestion are particularly common between Curry
Village and Yosemite
Lodge. Highly congested locations include the four-way
intersection near Curry
Village. Traffic congestion
typically causes delays for visitors in private vehicles, leads
to increased vehicle emissions, and disrupts the operation of the
Valley shuttle system.
Extensive
use of road shoulders for parking occurs during the peak visitation
periods. On a busy day, most dedicated parking areas are fully occupied,
with parking spilling onto roadway shoulders throughout the east
end of the Valley. This uncontrolled parking leads to pedestrian,
bicycle, and vehicular conflicts; damage to vegetation and soils
along the road edge; and the formation of social trails. Roadside
parking also disrupts natural views and lends an urban character
that is out of place in the Yosemite Valley
setting.
The
primary roadway used to access the project area is El
Portal Road, which is open year-round and provides snow-free access to Yosemite
Valley throughout most of the year. The road is typically
surrounded by steep, rocky canyon walls with small river flats and
terraces. Portions of El Portal Road
are characterized by narrow travel lanes, minimal shoulders, and
tight curves. These elements combine to create an unsafe environment
for vehicle travel, especially large vehicles. The narrow lane widths
(9.5 feet)
create a hazardous condition for buses, which average 8.5 feet
in width, and other large vehicles. El
Portal Road turns into Southside
Drive, which is located to the north
of Curry Village.
Southside
Drive and Northside
Drive are the two main access roads serving
the project area. Southside Drive
is located to the south of the Merced River,
while Northside Drive
is located to the north of the river. Four bridges cross the Merced
River, connecting Southside
Drive and Northside
Drive. One-way traffic flow is maintained along
Southside Drive
from Pohono Bridge
at the west end of the Yosemite Valley to
Stoneman Bridge
near Curry Village.
Three one- and/or
two-way roadways provide access to the
Curry Village
section of Yosemite Valley. These three access
roadways to Curry Village
are located off of Southside Drive.
Southside
Drive is used to access the Curry
Village area and the
overall project area from El Portal Road,
while Northside Drive
is used for traveling west, toward El Portal
Road. After the intersection of Northside
Drive and Southside
Drive, just beyond the westernmost edge
of Curry Village,
the roadway continues east as Southside
Drive. Once Southside
Drive passes Stoneman Meadow and reaches
the Upper and Lower Pines Campground areas, it turns into Happy
Isles Loop Road.
This roadway provides a loop, which heads south
between the South Camp and Upper Pines Campground area, loops around
to the northeast, and eventually comes back between the North Pines
amphitheater and Lower Pines Campground area to the north and Upper
Pines Campground to the south.
Curry Village and
East
Yosemite Valley Campgrounds Access and Parking
Curry Village
Curry Village is a major destination point in Yosemite Valley that receives very high visitation. During
the peak season, the area is very congested leading to pedestrian,
bicycle, and vehicular conflicts. Visitors to Curry Village experience congestion at the entrance roadway
and insufficient parking to serve visitor demand. Parking for day
visitors and overnight guests is unrestricted and visitors park
in scattered lots and along roadsides. Traffic congestion occurs
on Southside Drive, especially from vehicle recirculation to find
parking. Conflicts between vehicles and pedestrians take place when
pedestrians cross parking areas and roads to reach Curry Village attractions.
There
are three main roads to the Curry
Village area. The main access road (Curry Village Road)
is at the juncture between Southside Drive and Northside Drive;
an exit roadway is located directly to the west of the Curry Orchard;
and another access road is located to the northwest of Curry Village.
Two large parking lots are located east of Curry Village Road. One lot is constructed of asphalt and is visible
from the tent cabins, while the other has asphalt roads and hard-packed
earth parking bays within an orchard of apple trees. West of the
main entry road is an asphalt parking lot. Situated along the northwestern
access road is a parking area, as well as an exit for the long-term
parking lot located off of the main entrance road.
Amphitheater
at Clark’s Bridge
The
amphitheater location is currently open space. The equestrian facilities
located north of this site are accessed via an unpaved/hard-packed
access spur off of the Happy Isles Loop Road that runs directly
through the amphitheater area. A multi-use trail located north of Happy
Isles Loop Road connects with the access roadway spur and continues
north through the area. No parking is provided in the area, except
for parking spaces associated with the equestrian facilities.
South
Camp
The
South Camp area, bordered to the east by Happy Isles Loop Road,
is used for overflow parking during the summer months. There are
no National Park Service–maintained internal roadways in this area.
A hiker/stock trail paralleling the Happy Isles Loop Road to the
west and south runs along the edge of South Camp.
Upper
Pines Campground
The
Upper Pines area is accessed via the Happy Isles Loop Road, with
one entrance to the north. There are six loops accessing 240 drive-in campground sites. Parking for this area is located
directly off of the six campground loops. An area east of the development
is open space with thick forest cover. All access roads through
this portion of the project area are unpaved.
Lower
Pines Campground
The
Lower Pines Campground area is accessed via a campground road off
of Happy Isles Loop Road. This access roadway is directly north
of the access spur for the Upper Pines Campground area to the south.
There are eight drive-in
campground loops at Lower Pines. Parking in this campground is provided
at each drive-in
campground site (currently 78).
The multi-use trail that runs directly to
the north of Happy Isles Loop Road is the only circulation path
that intersects this project area. The access road throughout the
Lower Pines site is unpaved/hard-packed.
Visitor Experience
There
are two intertwined purposes for Yosemite
National Park according
to its enabling legislation and the National Park Service Organic
Act of 1916:
The
first is the preservation of the resources that contribute to Yosemite’s
uniqueness and attractiveness – its exquisite scenic beauty; outstanding
wilderness values; a nearly full diversity of Sierra Nevada environments,
including the very special sequoia groves; the awesome domes, valley,
polished granites, and other evidences of the geologic processes
that formed the Sierra Nevada; historic resources, especially those
relating to the beginnings of a national conservation ethic; and
evidences of the Indians who lived on the land. The second purpose
is to make the varied resources of Yosemite
available to people for their individual enjoyment, education, and
recreation, now and in the future (NPS 1980).
Visitor Use
In
1998, about 80% of all visitors to Yosemite National Park traveling in their own vehicles visited Yosemite Valley. An estimated 2.1
million visitors came to the Yosemite
Valley
in 1998; over 50% of those visitors came in July and August. On an average
day during the peak visitation season, an estimated 10,950
day visitors and 6,383 overnight visitors
were in the Yosemite
Valley
for at least a portion of the day. Yosemite
Valley
day visitors traveling in their own vehicles stayed an average of
4.2
hours, while overnight visitors stayed an average of 2.7
days (Gramann 1992). In Yosemite Valley, campground and lodging room stays are limited
to 7 days, and many campers stay the full
7 days (NPS 2000a).
Eastern Yosemite Valley has a free shuttle bus service that served
about 2.6 million riders in 1998.
This free shuttle bus service, which stops at Curry Village and the Upper Pines and Lower Pines Campgrounds,
offers visitors access to lodging, camping, and principal features
and use areas. About 45% of Yosemite Valley visitors reported using the shuttle buses,
and more than 90% of those visitors reported a satisfactory
experience (Gramann 1992).
The
Yosemite Valley Experience
Visitor
experiences in Yosemite Valley are very individualized.
Some visitors come to see the icons of Yosemite—the
waterfalls and geologic features. Others visit to experience a place
they have found unique, for personal challenges, timelessness, a
place and pace different from their day-to-day experiences, or for a personal
connection with the grandeur or intricacies of Yosemite
Valley. Yosemite Valley provides
a transition zone—a place neither urban nor wilderness, but with
elements of both. The Curry
Village project area
is a prime example, offering camping, lodging, and other amenities
typical of a more developed environment, but set in a natural environment
and thus maintaining the feeling of being in the woods.
Along
with natural darkness, the night sky plays an important part in
the overall visitor experience. There are excellent opportunities
for gazing at the moon and stars in the natural darkness of Yosemite
Valley. The Valley floor is extremely dark at night,
largely due to the Valley walls and limited sky exposure. Apart
from developed areas that have lighting for safety purposes, there
is essentially no ambient lighting within the park. Curry
Village is one of the
developed areas where lighting ensures a safe environment for visitors
and employees. The campgrounds near Curry
Village have a small
amount of lighting, but it is very specific and incidental, such
as the lighting around restroom doors. There is no lighting on roads
in Yosemite Valley.
Recreational
Opportunities
Yosemite Valley
The
project area offers a wide variety of recreational activities, including
sightseeing, photography, hiking, bicycling, stock use, swimming/wading,
fishing, picnicking, attending interpretive programs, rafting, and
ice skating. Activities that are common throughout the project area
are outlined below, followed by a discussion of recreation opportunities
specific to each of the five sites within the project area.
Sightseeing
and Photography
Sightseeing
is a very important recreation activity, as about 90%
of visitor groups reported sightseeing as an activity their parties
participated in while in the park (Gramman 1992).
Sitting or standing quietly, absorbed in thought or in awe of one
of Yosemite’s majestic views, was found to
be basic to the park experience. There are several sightseeing tours
available in Yosemite Valley. Tours include
a two-hour trip
around the Valley floor, a trip up to Glacier Point, a tour to the
Mariposa Grove of Giant Sequoias, and the Yosemite National Park
Grand Tour, which combines the tours to Glacier Point and the Mariposa
Grove.
The
sightseeing and photography opportunities within the project area
are generally the same for each specific site. Many of the major
sightseeing attractions surround the Curry
Village project area.
Views of Half Dome, Yosemite
Falls, Glacier Point,
Merced River, Tenaya
Creek, Washington
Column, Royal Arches, and Stoneman Meadow are available from various
places within the project area. Opportunities for photography within
the project area include these spectacular landmarks as well as
the natural scenery of each specific area.
Hiking,
Bicycling, and Stock Use
Hiking
is a popular activity in Yosemite Valley;
42% of summer visitors
and 52% of off-season visitors reported taking
nature walks (Gramann 1992).
About 35 miles of
hiking trails are available on the Yosemite Valley
floor; approximately 22 miles are shared with horseback riders,
and 12 miles are
shared with bicyclists. Trails within the project area lead to destinations
such as Mirror Lake
and Happy Isles. Visitors to any of the project sites located on
the shuttle bus route have access to trails and trailheads throughout
Yosemite Valley. Trails are shown on figure
III‑9.
Bicycling
is a common means for enjoying and exploring Yosemite
Valley. In the 1992
Gramman study, about 11%
of visitors surveyed included bicycling in their activities while
in the park, mostly in Yosemite Valley. Bicycles
are allowed only on the paved trails and roads within the project
area.
Swimming
and Wading
Swimming
and wading in the Merced River, easily accessed
from the Upper Pines and Lower Pines Campgrounds, are popular summer
activities. Swimming is also popular in Tenaya Creek. There is a
public swimming pool available at Curry
Village.
Picnicking
There
are four designated picnic areas in the Yosemite Valley,
at Cathedral Beach,
Sentinel Beach,
El Capitan, and Swinging
Bridge. Picnicking is
also popular along the Merced River, especially
where there are turnouts or wide shoulders for parking.
Interpretive
Programs
The
National Park Service and other park organizations provide interpretive
programs to the public to inform and educate visitors about the
relationship of park ecosystems and the importance of stewardship
and resource protection. Evening interpretive programs are given
on various topics by park interpreters at the amphitheaters located
in Curry Village
and the Lower Pines Campground.
Curry
Village
Hiking and Bicycling
Curry
Village offers access
to several trails and some trailhead parking. The main trail that
runs through Curry Village
is for pedestrian and stock traffic only. It runs through the Village
south to Happy Isles or northwest along the main road through Yosemite
Valley. There is also an easy, self-guided
trail entitled “The Legacy of Curry Village,” which commemorates
Camp Curry’s
early days. The Valley Loop Trail also runs through the Curry
Village area. This paved
bikeway/pedestrian trail follows the main road through Yosemite
Valley and branches off into Curry
Village at the four-way stop. One branch follows the
road, past the ice rink, and ends near the Curry
Village grocery store. The other branch goes east toward the Upper, Lower, and North
Pines Campgrounds. During the summer, bicycles can be rented at
Curry Village. Bicycles are allowed on the paved roads and
paved bikeway/pedestrian trails throughout Curry Village.
Other
Activities
Curry Village offers several other recreational activities,
including rafting, ice skating, and attending programs offered by
the Mountaineering School. Seasonal rafting is available on the Merced River in designated sections. Rafts are available
for rental in Curry Village. Ice skating, popular in the winter among residents
and visitors, is offered at a concessioner-operated
rink in Curry Village. Lessons and skate rentals are available, as
are cross-country ski rentals. Several recreational activities
are also provided by the Yosemite Mountaineering School and Guide Service, located in Curry Village, from April to November. The school rents mountaineering
equipment and offers rock climbing lessons and seminars, guided
hiking trips, and overnight backpacking trips.
Amphitheater
at Clark’s Bridge
Hiking and Bicycling
A
portion of one trail passes through this small site. This trail
is part of the paved bikeway/pedestrian trail that follows the road
between the Lower and Upper Pines Campgrounds. The trail continues
past these campgrounds, across the entrance road to
the
North Pines Campground, and ends at the road to the Yosemite Valley stable. The stable road and trail ending are
within the amphitheater site. Bicycles are allowed only on the paved
trail.
South
Camp
Hiking and Bicycling
There
is one trail in this area; it runs along the Happy Isles Loop Road and is used for pedestrian and stock traffic
only. This trail runs south to Happy Isles and north to Curry Village. The Happy Isles Loop Road is accessible to bicycles. Upper Pines
Campground
Upper
Pines Campground
Hiking and Bicycling
Trails
that surround the Upper Pines Campground lead to several destinations.
At the south end of the campground, trails lead south to the Nature
Center at Happy Isles
and farther southeast to trailheads for the John Muir Trail and
Mist Trail. Trails near the south end of the campground also lead
north toward Mirror Lake
following the Happy Isles Loop Road, and to the North Pines Campground
via the trail around the north side of the Merced River.
A trail also runs along the Happy Isles Loop Road west of the campground
toward Curry Village.
Finally, a paved trail runs between the entrances to the Lower and
Upper Pines Campgrounds and continues on to the North Pines Campground.
Bicycling is allowed on the Happy Isles Loop Road and on the paved
trail between the Lower and Upper Pines Campgrounds.
Lower
Pines Campground
Hiking and Bicycling
Several
trails run through this area. There is a trail from Curry
Village to the northern
part of the Lower Pines Campground. North of the Lower Pines Campground
is a paved trail that leads east to Mirror Lake Road or west to
the main road through Yosemite Valley. A hiker/stock trail parallels
this paved trail. There is also a paved trail that runs between
the Lower and Upper Pines Campgrounds west toward Curry
Village or east toward
North Pines Campground. Bicycles are allowed near the Lower Pines
Campground on the paved bikeway that runs between the Lower and
Upper Pines Campgrounds and on the bikeway north of the campground.
Visitor Services
Curry Village and East Yosemite Valley Campgrounds
Camping
The
three Yosemite Valley campgrounds on the
reservation system are located in the Curry
Village project area.
These campgrounds account for a total of 404
campsites of the park’s 475
campsites. All campgrounds except the Backpackers Campground have
a check-in station. There is a high demand
for camping, especially between May and September; of the 37,000
reservations made per year, 33,000 were for these months. In 1990-1991, about 27% of parties arriving in the summer by private vehicle
camped in the park (Gramann 1992).
The campsites are closely spaced, and there is little division between
user types. Car/tent campers, recreational vehicles, and others
are adjacent to each other, with an allowance of two vehicles per
campsite. There are no recreational vehicle hookups within the campgrounds.
Showers are available in Curry
Village.
In
relation to the specific sites within the project area, there is
camping at Upper Pines and Lower Pines. The Upper Pines Campground
has 240 drive-in sites and is open all year. The
only recreation vehicle dump station is located at Upper Pines.
The Lower Pines Campground has 78
drive-in sites and is open from March
to October. The third reservation campground is the North Pines
Campground, which has 86
drive-in sites and is open from April
to September. This campground is adjacent to the amphitheater site.
South Camp is a new campground outlined as an action in the Yosemite Valley Plan.
Lodging
Curry
Village is the only place
within the project area that has lodging facilities. There are 427
rustic units, 181 economy units, and 20 midscale units. There are cabins with
and without private bathrooms, tent cabins, and lodge units in Stoneman
Lodge, for a total of 628
units out of the park’s 1,260 units.
Other
Services
Food
is available at the Curry Pavilion, Pizza Patio, and taqueria. There
is also a small grocery store with camping supplies and gifts, a
seasonal post office, and the Mountain Shop.
Socioeconomics
The
affected socioeconomic region includes Madera
County, Mariposa
County, and Tuolumne
County, the three counties
in which Yosemite National
Park is located. The Yosemite
Valley Plan provides a socioeconomic profile of the regional
economy for 1996 that presents the size of each county’s
principal economic sectors in terms of population, employment, and
output. Output data have been updated based on trends in local area
personal income provided by the U.S. Bureau of Economic Analysis
through the year 2000 (the most recent data available
for the area). The resulting estimates in 2000
provide a reasonable socioeconomic profile of the three-county region, given that it has not experienced any
significant structural changes to its economy since 1996. Employment data for 2000
is provided by the California Employment Development Department.
Visitor
Population
Three
categories of visitors visit the park: park overnighters, local
overnighters, and day visitors. Park overnighters are park visitors
who lodge or camp overnight within the park. Overnight visitation
in the park is controlled by the National Park Service and limited
by the availability of lodging and camping facilities. Local overnighters
are park visitors who lodge or camp within the Yosemite
region during their trip. Typically, these visitors spend several
days visiting the park. Day visitors are park visitors who either
do not lodge or camp overnight in the region or are local residents.
The 1997-1998
Yosemite Area Regional Transportation Strategy visitor survey estimated
that park overnighters constitute about 20%,
local overnighters 40%,
and day visitors 40%
of the park visitor population. Classified by National Park Service
definitions, day visitors total 80%
of the visitor population and overnight visitors constitute 20%.
Table
III‑10 shows the overnight populations accommodated
within the project area. The Final
Yosemite Valley Plan/SEIS determined the average length of stay
for park overnighters to be 2.7 days.
|
Table
III-10
Existing Overnight Lodging
|
|
Location
|
Accommodations
|
Number
|
|
Curry
Village
|
Rustic
Units
|
174
|
|
|
Economy
Units
|
288
|
|
|
Midscale
Units
|
25
|
|
|
Deluxe
Units
|
0
|
|
Campgrounds
|
|
|
|
Upper
Pines
|
Drive-in
|
270
|
|
Lower
Pines
|
Drive-in
|
60
|
|
Source:
NPS 2000a
|
Day
visitation to the park on an average summer day is estimated at
10,950, and approximately half of Yosemite
day visitors lodge or camp overnight in the five-county
region (local overnighters). Other day visitors stay overnight outside
the affected regions (either at their homes or other accommodations)
and are identified as day visitors. The greatest percentage of local
overnight visitors stay in Madera
County, followed by Mono
County and Mariposa
County. The average length
of stay for local overnighters is 2.7 days.
An average length of stay for day visitors is 4.2 hours.
Regional
Economy
Population
In
2000, the total population
of the three-county
affected region was approximately 194,740
(see table III‑11). Madera
County is the most populous
county, with roughly 123,109
residents. Mariposa
County has a total population
of approximately 17,130
residents.
|
Table
III-11
Population by County
|
|
County
|
Population
|
|
Madera
|
123,109
|
|
Mariposa
|
17,130
|
|
Tuolumne
|
54,501
|
|
Total
|
194,740
|
|
Source:
U.S.
Bureau of the Census 2002
|
Employment
The
employment figures include all waged, salaried, and self-employed
jobs in each county, and both full-time
and part-time
workers. In 2000, total employment was approximately
60,040 in the three-county
area. Approximately 65% of the total employment in the affected
region was in Madera County. Mariposa County accounted for approximately 8% of total employment
in the affected region. Table III‑12 provides
total employment estimates for the counties by industry sector.
|
Table
III-12
2000 Employment by Major Industry Sector
|
|
Industry
Sector
|
Madera
|
Mariposa
|
Tuolumne
|
Total
1
|
|
Agriculture
|
11,900
|
10
|
180
|
12,090
|
|
Construction
& Mining
|
1,600
|
140
|
980
|
2,720
|
|
Manufacturing
|
3,400
|
180
|
1,250
|
4,830
|
|
Transportation,
Public Utilities
|
1,100
|
90
|
430
|
1,620
|
|
Trade
(Wholesale & Retail)
|
5,700
|
690
|
3,800
|
10,190
|
|
Finance,
Insurance, Real Estate
|
600
|
90
|
530
|
1,220
|
|
Services
|
7,500
|
1,970
|
4,230
|
13,700
|
|
Government
|
7,600
|
1,730
|
4,540
|
13,870
|
|
Total
|
39,200
|
4,890
|
15,950
|
60,040
|
|
1
Totals may not exactly compute due to rounding
Source:
California Employment Development Department 2002
|
Output
Economic
output is a measure of productivity. Measures of economic output
vary depending upon the industry sector. For the agricultural, wholesale
trade, and retail trade sectors, output is measured by the value
of products sold. In the manufacturing sector, output is a measure
of the value added by the manufacturer or the value of shipments.
In the service sector, output is measured as receipts in dollars.
The
estimated total output of goods and services for the three-county affected
region in 2000 was about $6.9 billion (2000 dollars) (table III‑13). Madera
County accounted for approximately 66% of total economic
output in the affected region. Mariposa County, which had the smallest economy in the affected
region, accounted for approximately 7% of output. Based on output,
manufacturing was the largest economic sector in the three counties.
|
Table
III-13
2000 Economic Output by County and Industry Sector (in Millions
of 2000 Dollars)
|
|
Industry
Sector
|
Madera
|
Mariposa
|
Tuolumne
|
Total
1
|
|
Agriculture
|
$1,080.6
|
$28.3
|
$44.3
|
$1,153.2
|
|
Construction
& Mining
|
$322.5
|
$54.1
|
$234.2
|
$610.8
|
|
Manufacturing
|
$989.1
|
$53.0
|
$345.4
|
$1,387.5
|
|
Transportation,
Public Utilities
|
$434.8
|
$65.5
|
$199.6
|
$699.9
|
|
Trade
(Wholesale & Retail)
|
$280.9
|
$17.8
|
$122.4
|
$421.2
|
|
Finance,
Insurance, Real Estate
|
$494.7
|
$103.2
|
$315.9
|
$913.8
|
|
Services
|
$479.5
|
$59.2
|
$371.4
|
$1,010.1
|
|
Government
|
$363.7
|
$89.4
|
$243.5
|
$696.6
|
|
Total
|
$4,545.8
|
$470.5
|
$1,876.8
|
$6,893.1
|
|
1
Totals may not add up exactly due to rounding
Source:
Micro IMPLAN Group 1996, adjusted according to U.S. Bureau
of Economic Analysis trends in personal income
|
Taxable
Retail Sales
Taxable
retail sales are good indicators of annual spending in the travel-service
sectors, since they represent the taxes paid for transactions with
consumers. The total taxable retail sales figures include the taxes
paid for transactions with customers. The total taxable retail sales
figures include the taxes paid by businesses on raw materials and
services. In 2000, the total taxable retail sales for the affected
region was approximately $1.5 billion (2000) dollars. Madera County accounted for about 58% of total taxable retail
sales. Mariposa County accounted for about 8% of total taxable sales.
Table III‑14 shows total taxable sales by County.
|
Table
III-14
2000 Total Taxable Retail Sales by County (in Millions of
2000 Dollars)
|
|
County
|
Total
Taxable Sales
|
|
Madera
|
$881.0
|
|
Mariposa
|
$127.3
|
|
Tuolumne
|
$500.8
|
|
Total
|
$1,509.1
|
|
Source:
California State
Board of Equalization 2002
|
County
Profiles
Madera
County.
The central economic activity in Madera County is agriculture, which constitutes nearly one-third
of the county’s total employment and over 24% of the county’s economic
output (tables III‑12 and III‑13).
The agricultural sector stimulates production in related sectors
of the economy, including jobs in food processing, transportation,
and wholesale trade.
In
Madera County, the construction and mining sector accounts
for over 4% of employment and over 7% of total economic output in
the county (tables III‑12 and III‑13).
Mariposa
County.
Recreation and tourism are major industries
in Mariposa County. The county’s primary recreation area/tourist
attraction is Yosemite National Park, much of which lies within the county, including
the developed areas of Yosemite Valley. Major recreation areas in Mariposa County include Stanislaus National Forest and Sierra National Forest, including the U.S. Forest Service/Bureau of
Land Management-managed recreation areas along the Merced River.
The
services sector accounts for approximately 40% of employment and
22% of economic output in Mariposa County. Government is also a major economic sector
in the county, accounting for 35.4% of employment and 19% of total
output. The finance, insurance, and real estate sector accounted
for 22% of economic output, although only about 2% of total employment.
In
Mariposa County, the construction and mining sector accounts
for only 3% of county employment and 11.5% of total economic output
in the county (tables III‑12 and III‑13).
Tuolume
County.
A portion of Yosemite National Park is in the southeastern portion of Tuolumne County. The government sector was the largest employer
in the county in 2000, accounting for 28.5% of employment and 13%
of economic output (tables III‑12 and III‑13).
The services sector accounts for 26.5% of employment and 19.8% of
the total economic output. Most of the job growth in Tuolumne County is expected in the services, retail trade,
construction, and manufacturing sectors. The services sector is
expected to create the greatest number of new jobs, reflecting an
increased demand for business, health, personal, and hospitality
services.
In
Tuolumne County, the construction and mining sector accounts
for nearly 6% of county employment and 12.5% of total output for
the county (tables III‑12 and III‑13).
