Yosemite Valley Plan SEIS, Volume IB Part 2, Chapter 4: Alternative 3

The analysis of potential impacts from actions implemented under Alternative 3, Taft Toe Parking (No Out-of-Valley Parking), are presented in this section.

This section analyzes impacts on water resources: hydrology, including floodplain values, and water quality. Impacts on water resources are described by area (i.e., Yosemite Valley, El Portal, Wawona, and out-of-Valley parking locations) and are characterized as long-term alterations or restoration of hydrologic processes (e.g., water flow and flood regime) or water quality (e.g., turbidity, and non-point source pollution from vehicles or recreational use).

Actions to implement the River Protection Overlay include the removal of development within 150 feet of the river. These actions would restore the river to more natural geomorphologic conditions through restoration of stream banks (i.e., stream bank stability) and the 100-year floodplain. The River Protection Overlay would allow natural processes to prevail in the river and floodplain and minimize the alterations of the floodplain due to existing and future facilities. Further, removal of development from the River Protection Overlay would potentially reduce visitor degradation of stream banks and the river channel by concentrating visitor use away from the river. Examples of these areas include Housekeeping Camp, certain meadow roads and turnouts, and riverside campgrounds. Removal of facilities from the River Protection Overlay would allow natural floodplain alterations and lateral movement of the river channel (i.e., meandering), and increase opportunities for restoration of riparian vegetation, which would reduce unnatural erosion and deposition. Ultimately, the implementation of the River Protection Overlay would result in a regional, long-term, major, and beneficial impact on hydrology and floodplain values.

Camp 6 would be restored between Northside Drive and the Merced River, allowing for restoration of some of the oxbows and cut-off channels that once existed in the area. Changes to the existing river dynamics through restoration of oxbows and braided streams could, over time, become more locally pronounced and eventually contribute to restoration of natural stream flow conditions downstream of the area. Restoration actions at Camp 6 would result in localized, long-term, major, and beneficial impacts on hydrology and the floodplain values.

The construction of a parking facility and transit center at Taft Toe would alter surface hydrology by the removal of vegetation and replacement with an impervious surface. In addition, riverbank instability (soils compaction and vegetation loss) could be the result of radiating impacts associated with the increased concentration of visitors. As a result of these alterations to hydrology, there would be a localized, minor, long-term, adverse impact on hydrology.

The parking facility and transit center at Taft Toe would be constructed largely outside of the 100-year floodplain, but the concentration of visitors would have radiating impacts to the river and its hydrologic processes. This would be a long-term, minor, adverse impact.

At Yosemite Lodge, Northside Drive would be rerouted to the edge of the 100-year floodplain and parking would be reconfigured, but would remain in the 100-year floodplain. This would result in a long-term, minor, adverse impact on hydrology because flood flow would be altered.

The removal of three structures at Ahwahnee Row that are located in the 100-year floodplain would have a localized, long-term, minor, beneficial impact on floodplain values by removing impediments to flood flow (particularly pooling in this area).

Restoration areas include the portions of Yosemite Lodge (including motel units that impede flood flow and the former cabins area), Upper and Lower River Campgrounds, North Pines Campground, and roads from Stoneman and Ahwahnee Meadows that are in the 100-year floodplains. Removal of these facilities and restoration would restore the hydrologic process of flooding, and would be a long-term, moderate, beneficial impact on hydrology.

The presence of a bridge as a fixed structure within a river course can cause alterations in river flow and result in localized morphologic changes to the beds and banks of the river. Morphologic changes attributable to bridge placement, and that are most readily observable, would include scour holes on the downstream side of the abutment, formation of deposition bars downstream of the scour holes, bank instability, unnatural erosion and deposition, changes in flow velocity, and localized channel widening. Removal of these fixed structures would provide for restoration of natural erosion and deposition processes; allow the river to meander and naturally alter course; and reduce flooding potential by removing flow impediments. The impacts of bridge removal would be noticeable as the scour holes and downstream deposition bars caused by their in-river abutments diminish and the riverbank is reestablished by natural flow patterns. Bridge removal would continue to improve natural river flow dynamics along extended reaches of the river, and the impacts would be observable for years to come.

Sugar Pine Bridge constricts the river severely, largely because this bend of the river immediately downstream of the Tenaya Creek confluence has always been dynamic. The approach road that connects Ahwahnee Bridge to Sugar Pine Bridge eliminated the numerous small cutoff channels that existed prior to construction in 1929. The loss of the numerous small cutoff channels, combined with the constriction of the river by Sugar Pine Bridge, has forced the creation of a single large cutoff channel immediately adjacent and parallel to the approach road. Removal of Sugar Pine Bridge and the approach road and restoration of the riverbank (vegetation, bank slope, channel width) would be a localized, long-term, major, beneficial impact on the Merced River’s hydrology, by reducing unnatural erosion and scouring, by reducing unnatural deposition downstream of the bridge, and by allowing the river to meander.

Stoneman Bridge constricts the river severely, causing increased velocities during high flow and the resultant formation of a downstream scour pool and mid-channel bar. The presence of the bar has caused erosion rates to increase unnaturally along the left (southern) bank. The constricted channel width has also had upstream impacts, with flood waters backed up behind the bridge causing erosion on both banks. Removal of Stoneman Bridge and restoration of the riverbank (vegetation, bank slope, and channel width) would be a localized, long-term, major, and beneficial impact on the Merced River’s hydrology, by reducing scouring and unnatural erosion both upstream and downstream of the bridge, by reducing unnatural deposition downstream of the bridge, and by allowing the river to meander.

Housekeeping Bridge moderately constricts the river and has three center piers in the river channel that cause increased velocities, formation of three scour holes at the bridge, and downstream erosion (particularly at the left bank). Removal of Housekeeping Bridge and restoration of the riverbank (vegetation, bank slope, and channel width) would be a localized, long-term, moderate, beneficial impact on the Merced River’s hydrology by reducing scouring and unnatural erosion.

Superintendent’s Bridge minimally constricts the river, but has center piers in the river channel that interfere with transport of large, woody debris. Removal of Superintendent’s Bridge would be a localized, long-term, minor, beneficial impact on the Merced River’s hydrology by allowing free movement of large, woody debris.

Removal of these four bridges would also be a localized, long-term, major, beneficial impact on floodplain values by removing impediments to flood flow, particularly large flood events such as the January 1997 flood event. Local, short-term, minor, adverse impacts may occur during bridge removal due to deconstruction activities in the main river channel.

At Yosemite Creek, the human built rock rubble pile blocking the western channel would be removed, as would the pedestrian bridge and its abutments immediately upstream of the Yosemite Creek Bridge (vehicle). Removal of these impediments would restore hydrologic processes such as annual spring runoff, particularly restoration of flow to the western channel of the braided stream network, and would be a long-term, minor, beneficial impact on hydrology. Local, short-term, negligible, adverse impacts to hydrology may occur during removal due to the deconstruction activities in the western channel during low water.

A new vehicle bridge would be constructed downstream of the existing Yosemite Creek Bridge. The abutments of the new bridge would be outside of ordinary high water and would minimally impact hydrologic processes. This would result in a long-term, minor, adverse impact on hydrology. Local, short-term, minor, adverse impacts to hydrology may occur during bridge construction due to construction activities in the main channel.

Cascades Diversion Dam was constructed in 1917 to impound water for the intake structure that diverted river flows to a downstream powerhouse. Use of the powerhouse to generate hydroelectric power was discontinued in 1985, as was the diversion of river flows. The dam is located at a natural breakpoint in the channel gradients: upstream of the dam the gradient is .01 feet/feet; downstream of the dam the gradient is .06 feet/feet. The pool and backwater created by the dam extend upstream from the dam about 550 feet. The dam is in danger of failure: outside of spring snowmelt runoff and rain-on-snow winter floods, water flows under the dam instead of through the spillway or over the dam. Failure of the dam would result in unmitigated release of the sediment trapped behind the dam, and materials that comprise the dam. Removal of the dam would have a localized, long-term, major, beneficial impact on the Merced River’s hydrology by preventing the adverse impacts of dam failure and restoring the free-flowing condition of the river: sediment transport would be unimpeded; natural low-water and flood flow would be restored; and riparian vegetation currently displaced by the pool and backwater would be restored on the riverbanks.

Removal of Cascades Diversion Dam would also be a localized, long-term, major, beneficial impact on floodplain values by removing a substantial impediment to flood flow: both annual spring runoff, and large flood events such as the January 1997 flood event.

Reconstruction of the El Portal Road between the Cascades Diversion Dam and Pohono Bridge could have a beneficial impact on hydrology if the footprint of the existing bank stabilization in the river is reduced, or could have an adverse impact on hydrology if the footprint of the existing bank stabilization in the river is increased. Additional environmental compliance, including a Wild and Scenic River Section 7 determination, would be necessary before this segment of road can be reconstructed.

Actions to implement the River Protection Overlay would remove sources of pollutants and reduce erosion and sedimentation by removing facilities and limiting activities associated with facility use and maintenance. These activities include vehicle maintenance, roadwork, and construction projects. Additionally, the possible realignment or relocation of roads, trails, and visitor facilities could reduce the introduction of refuse and bacteria by visitors. The removal of the concessioner stable and the Swinging Bridge Picnic Area and restoration to natural conditions would reduce a source of nutrients, coliform, turbidity, and other water pollutants from the Merced River. Actions to implement the River Protection Overlay would limit or remove development that is immediately adjacent to the river, thereby providing a buffer to impede the migration of non-point source pollutants from discharge areas to the Merced River.

The removal of parking spaces from Curry Orchard, Yosemite Falls, the concessioner stable, Camp 6, and roadside areas throughout the Yosemite Valley would substantially reduce the potential sources of non-point source pollution that are inherent in areas with heavy, concentrated vehicular use. Vehicles can release pollutants onto pavement, including asbestos, heavy metals, petroleum-based products, and other chemicals such as ethylene glycol. Some fraction of these chemicals can be carried by surface-water runoff to streams, and eventually the Merced River. A formalized parking facility would be established at Taft Toe, with stormwater pollution controls incorporated into its design (possible treatment methods include sand filters, underground water collection and treatment tanks, or oil/water separators). Replacing existing parking areas listed above with a formalized parking facility at Taft Toe would reduce non-point source pollution from stormwater runoff from large, paved surfaces, resulting in a regional, long-term, moderate, beneficial impact on water quality.

The increased use of shuttle buses would reduce the number of vehicle miles traveled in the Valley and allow the removal of some roads (e.g., roads through Stoneman and Ahwahnee Meadows). This would have long-term, minor, beneficial impact on water quality by reducing non-point source pollution.

As a result of a U.S. Army Corps of Engineers study (1998), the flood protection levee (hereafter, "levee") in the Hennessey’s Ranch area would need to be raised and extended in order to protect employee housing, the impacts of which would be two-fold.

First, the levee would limit and possibly redirect natural river flow through a localized reach of the river during a 100-year flood event, reducing channel width and increasing flows or eddies depending on floodwater velocity and height. The levee is above the normal high water line and would not affect the river flow during normal spring runoff periods. Increasing the length and height of the levee would be a localized, long-term, minor, adverse impact on the river’s hydrology because this reach of river has low susceptibility to bank scour, erosion, and slope instability.

Secondly, any structure intended to prevent flooding has the potential to limit the natural formation and function of that river’s floodplain. Most of the Merced River in El Portal is confined within a bedrock gorge channel, and the floodplain is narrow due to the river gradient and resistant bedrock. Consequently, the majority of the floodplain is more resilient and less susceptible to adverse impacts of altered river flow. The area at Hennessey’s Ranch is one of the few flat, alluvial floodplain sections adjacent to the Merced River at El Portal. The alluviated area was formed through years of river sediment deposition. After construction of the existing flood protection levee, this area was isolated from further sediment deposition because the levee height prevented inundation by large flood flow such as the January 1997 flood event, which was the largest flood event in the 80+ years of stream gauge data at the Pohono gauging station. When compared to the impact of the existing flood protection levee in the No Action Alternative, increasing the length and height of the levee would be a localized, long-term, minor, adverse impact on floodplain values because only flood flow greater than the January 1997 flood event would be affected.

Removal of housing from the River Protection Overlay at Hennessey’s Ranch and restoration of the area would have long-term, minor, beneficial impacts on hydrology by restoring river-related communities and hydrologic processes.

Construction of new housing in the 100-year floodplain but outside of the River Protection Overlay would require the modification of the levee (discussed above), and would result in radiating impacts to the river bank due to increased employees living in the area. These radiating impacts would have a long-term, minor, adverse impact.

Two pedestrian bridges would be constructed in the vicinity of Hennessey’s Ranch. The bridges and their abutments would be designed to not interfere with the free-flowing condition of the river, and the banks of this river reach are relatively stable and resilient. The two pedestrian bridges would have localized, long-term, minor, adverse impacts on the river’s hydrology and floodplain values. Local, short-term, minor, and adverse impacts to hydrology during construction due to construction activities in the main channel.

Actions to implement the River Protection Overlay would reduce discharge of non-point source pollutants into the river by providing a buffer area where development is removed (e.g., at Hennessey’s Ranch) and future development is constrained (e.g., at Village Center and Railroad Flat). Water quality could be adversely impacted at Village Center by runoff associated with increased parking spaces for both visitors and employees, although this impact would be mitigated by non-point source pollution controls at large paved areas. The increase in employees living in El Portal would likely result in increased recreational use of the river and subsequent increase in fecal coliform and bacteria levels, resulting in a regional, long-term, minor, adverse impact on water quality. Wastewater from all new buildings (e.g., housing, park headquarters, etc.) would be connected to the existing sanitary sewage system and would meet all applicable water treatment requirements. The impacts of this alternative on water quality in El Portal would be localized, long-term, minor, and adverse due to increased non-point source pollution resulting from increased development.

The project site at Foresta is approximately three-quarters of a mile from Crane Creek, but has no rivers, streams or other hydrologic features, and surface runoff is the only pertinent hydrologic process. A parking facility, Volunteers-in-Parks campground, 14 houses, and a new National Park Service stable at McCauley Ranch (depending on the outcome of the wilderness feasibility study) would be constructed in the Foresta area. These actions would have a localized, long-term, negligible, adverse impact on hydrology resulting from reduced ground cover and potentially increased runoff. These actions would result in increased non-point source pollution, which would be mitigated through stormwater pollution controls at the parking facility, and have a localized, long-term, minor, adverse impact on water quality.

The locations of these entrance stations have no major rivers, streams, or other hydrologic features. Surface-water runoff is the only pertinent hydrologic process. A visitor center and associated visitor service facilities would be constructed, resulting in reduced ground cover and potentially increased runoff. These actions would have a localized, long-term, negligible, adverse impact on surface water hydrology. These actions would have a localized, long-term, negligible, adverse impact on water quality resulting from increased non-point source pollution associated with development.

The collective actions of this alternative have regional, long-term, moderate, and beneficial impacts on the hydrology and water quality, largely due to the removal of facilities in Yosemite Valley from the River Protection Overlay and the 100-year floodplain and removal of the bulk fuel storage facility in El Portal. The beneficial impacts of removing three bridges, Cascades Dam, campsites, Housekeeping Camp units, etc., have been weighed against the adverse impacts on hydrology and water quality in El Portal due to increased development near the river.

This section assesses the impacts of past, present, and reasonably foreseeable actions to water resources. The actions identified below have generally occur within the watershed of the Merced River–both main stem and South Fork.

The water resources of the Merced River have been historically affected by a variety of actions within the floodplain since Euro-American settlement. In Yosemite Valley, the transportation network interferes with flooding and surface-water flow, and lodging, campgrounds, and other structures have been constructed in and immediately adjacent to the river channel. In El Portal, a large portion of the riverbank has been artificially stabilized to protect primary roads and buildings immediately adjacent to the river. Because artificial stabilization of the riverbank began in the 1800s, the Merced River has been separated for decades from substantial portions of its floodplain. During spring runoff floods, this riprap serves to keep the channel from moving, and quickly conveys the water downstream. During winter floods, artificial bank stabilization prevents damage to dwellings and roads in the best-protected sections, but increases bank destruction where there is little or no artificial bank stabilization.

The El Portal Road Improvement Project (NPS) is currently under way from the park boundary to the Cascades Diversion Dam, and affects river-related communities of the Merced River immediately adjacent to the roadway. Natural resources are protected during construction by implementation of a compliance monitoring program, erosion and sediment controls, hazardous materials controls, revegetation and reclamation, and excluding construction from sensitive habitats. Between El Portal and Yosemite Valley, riprap has been placed in some locations along the north bank of the Merced River to protect the reconstructed El Portal Road, altering the overall flow regime of the river.

Reasonably foreseeable future actions proposed in the region are separated below into four general categories: (1) projects expected to have a net beneficial impact; (2) projects expected to have both beneficial and adverse impacts; (3) projects expected to have a net adverse impact; and (4) projects that have no impact relative to the actions of this alternative.

Reasonably foreseeable future projects that could have a net beneficial impact to water resources of the Merced River include:

These projects would have net beneficial impacts on water resources through improved coordination of resource management activities and restoration, although there might be site-specific or short-term, adverse impacts.

Reasonably foreseeable future projects that could have both beneficial and adverse impacts to water resources include:

These projects would have beneficial impacts on water resources by removal of facilities, restoration, and slope stabilization, and adverse impacts on water resources through increased non-point source water pollution.

Reasonably foreseeable projects that could have a net adverse impact to water resources include:

These projects would have adverse impacts to water resources through increased use and facility development, which could result in stream bank instability and increased non-point source water pollution.

Beneficial impacts to water resources of past, present, and reasonably foreseeable future projects on the Merced River watershed would be related to removal of facilities from the river banks and floodplain, restoration of previously developed areas and areas significantly impacted or altered by visitor use, removal of channel obstructions, and reduced human-related impacts. Adverse impacts of these projects on the Merced River watershed would be related to increased use and facility development, which could result in stream bank erosion, soil compaction, loss of vegetation, refuse accumulation, non-point source pollution generation, and degradation of stream characteristics and water quality in the Merced River. Overall, the past, present, and reasonably foreseeable future projects would have a long-term, minor, beneficial impact on water resources. The actions of this alternative would have a long-term, minor, beneficial impact on water resources. The actions of this alternative, in combination with past, current, and reasonably foreseeable future projects, would have a long-term, minor, beneficial impact on water resources.

This evaluation identifies non-exempted actions within the floodplain that could increase or decrease risk to human life and property by adding or removing housing and facilities from floodplains. The proposed removal and addition of non-exempted facilities from the floodplain are listed below by area and summarized in table 4-58; all impacts would be long term unless otherwise noted (see plate E for Yosemite Valley flood extent). For related effects on floodplain values and hydrology, see the Water Resources section in this chapter.

Dam safety engineers have classified the Cascades Diversion Dam as a "high hazard potential structure" and assigned a Safety of Dams condition of "unsatisfactory." This classification requires immediate corrective action. The removal of the dam would be a long-term, localized, major, beneficial impact to human health and safety.

A moderate, beneficial impact would result from the removal of houses and test cabins (49 employee beds) and the concessioner stable from the floodplain. This beneficial impact would be related to reduced risk to both human life and property during a flood event. The removal of the kennel from the floodplain would result in a negligible, beneficial impact because potential property damage due to flooding would be reduced.

The removal of 212 housekeeping units and retention of 36 units in the 100-year floodplain would result in a moderate, beneficial impact because overnight lodging within the 100-year floodplain would be reduced, decreasing flood-related risk to both human life and property. Compared to the No Action Alternative, the beneficial effect related to human life would be limited, however, because the units are not in use during the winter flood season.

Removal of the Concession Headquarters, Indian Creek employee housing (14 employee beds), and removal of three Ahwahnee Row houses (three employee beds) from the 100-year floodplain would result in an overall moderate, beneficial impact because fewer people would be living and working within the floodplain, and flood hazard related to human safety would be reduced. Redevelopment of this area would minimize placement of structures in the floodplain, and include mitigation measures to protect people during flood events. With mitigation, in accordance with National Park Service Floodplain Management Guideline, risk to both human safety and property would be a minor, adverse impact.

Table 4-58 Non-exempted Facilities in the Floodplain
Facility Location	Development Change In The Floodplain¹	Impact Intensity/Type²
Yosemite Valley
Cascades Diversion Dam	Remove Cascades Diversion Dam	Localized, Major, beneficial
Concessioner Stable Area	Remove Stables and associated housing (49 employee beds) and restore area Remove Kennel and restore area	Moderate, beneficial Negligible, beneficial
Housekeeping Camp	Remove 212 lodging units out of the floodplain. Retain 36 lodging units in the floodplain and 16 lodging units out of the floodplain.	Moderate, beneficial
Yosemite Village	Remove 3 Ahwahnee Row houses (3 employee beds) Remove Concession Headquarters Redevelop Concession Headquarters as parking/visitor services Remove Indian Creek employee housing (14 employee beds) Redevelop Indian Creek employee housing area as parking/visitor services	Moderate, beneficial Moderate, beneficial Minor, adverse Moderate, beneficial Minor, adverse
Yosemite Lodge Area	Remove the Superintendent’s House (Residence 1) and restore area Remove 5 motel units Relocate Wellness Center and nearby custodial cabins out of the floodplain Develop new overnight parking	Moderate, beneficial Moderate, beneficial Minor, beneficial Negligible, adverse
El Portal
Village Center	Redevelop for necessary support facilities and commercial services Adaptively reuse El Portal Hotel (remove 12 employee beds) and Yosemite Institute Office Remove bulk fuel storage facility Remove El Portal Motor Inn cabins (remove 24 employee beds)	Negligible, adverse Moderate, beneficial Moderate, beneficial Moderate, beneficial
Hennessey’s Ranch	Add 656 employee beds Remove 68 employee beds at Trailer Village Remove 4 employee beds at Abbieville	Moderate, adverse Moderate, beneficial Moderate, beneficial

Removal of the Superintendent’s House (Residence 1) and five motel units from the floodplain would result in a moderate, beneficial impact because overnight lodging within the floodplain and the associated risk to human safety and property would be reduced. Relocation of the Wellness Center and nearby custodial cabins outside the floodplain would also result in a minor, beneficial impact because the number of facilities and people working within the floodplain would be reduced, resulting in a reduction in the flood hazard related to human safety and property. New overnight parking would be developed that incorporates design standards to minimize the effect on flood flow and allow for runoff, resulting in a negligible, adverse impact. Adverse effects in the Yosemite Lodge area would be further reduced by designs that minimize impacts on natural flood processes and flood damage to structures, and by preparation of evacuation plans and routes (evacuation routes would be located outside the floodplain).

Moderate, beneficial impacts at the Village Center would result from the adaptive reuse of El Portal Hotel (removal of 12 employee beds and relocation of Yosemite Institute Office), and the removal of the Motor Inn cabins (24 employee beds) because overnight occupation of the floodplain would be reduced. Removal of the bulk fuel storage facility would result in a moderate, beneficial impact on human safety because the number of people living and working within the floodplain would be reduced. Adaptive reuse of these facilities would include mitigation consistent with National Park Service Floodplain Management Guideline to reduce the risk of property damage due to flooding.

Parts of the Village Center area that would be redesigned to support commercial services and parking would be placed out of the floodplain where possible. For new structures constructed in the floodplain an evacuation and safety plan would be developed. With these mitigation measures in place, there would be a minor adverse impact.

The construction of 656 new employee beds at Hennessey’s Ranch would be a major, adverse impact on human safety because new employee beds would be constructed within the 100-year floodplain. However, because mitigation would be incorporated into the design to protect employees and structures during flood events (e.g., raising and extending the levee, evacuation planning), the overall impact would be reduced to moderate and adverse.

There would be no impact to the South Fork Merced River floodplain because the employee housing considered for Wawona would be outside the floodplain.

Beneficial impacts in Yosemite Valley would include removal from the floodplain of 212 housekeeping lodge units, the kennel, concessioners stables and associated housing (49 employee beds), the Superintendent’s House (Residence 1), five Yosemite Lodge motel units, the Wellness Center and nearby custodial cabins, and 14 employee beds at Indian Creek. The Concession Headquarters and Indian Creek employee housing would be redeveloped as parking/visitor services, and new overnight parking would be developed at Yosemite Lodge which would have a minor adverse impact on the floodplain. Overall, the aggregate impact of these actions, in combination with mitigation in Yosemite Valley, would be moderate and beneficial, because the flood-related risk to human safety and property would be reduced.

Actions in El Portal would include removal from the floodplain of 36 employee beds (moderate, beneficial) and the bulk fuel facility (moderate, beneficial), removal or adaptive reuse of El Portal Hotel (employee housing and Yosemite Institute Office; moderate, beneficial), 656 employee beds at Hennessey Ranch (moderate, adverse), and redevelopment of Village Center (minor, adverse). Beneficial impacts would be related to reduction in the flood-related hazard to human safety. Adverse effects to both human safety and property associated with new development or redevelopment/adaptive reuse within the floodplain would be minimized by mitigation (e.g., design and siting specifications, extending and raising existing levees, and a mandatory evacuation plan) resulting in a net minor, adverse impact.

The total net effect of Alternative 3 would be moderate and beneficial because the number of people working and overnight lodging/housing within the floodplain would be reduced (reducing flood-related risks to human safety), and mitigation would be implemented to reduce adverse effects on human safety and property associated with development/redevelopment within the floodplain.

The impacts of past, present, and reasonably foreseeable actions to flood hazards discussed herein are based on analysis of past, present, and reasonably foreseeable future actions in the Merced River watershed from its source near the crest of the Sierra Nevada to Briceburg Bridge. The actions identified below include those projects that have the potential to affect the floodplain of the Merced River.

The Merced River has been historically affected by a variety of actions within the floodplain since Euro-American settlement. In El Portal, from the park boundary to Briceburg Bridge, a large portion of the riverbank has been artificially manipulated. Much of this manipulation is riprap used to stabilize the riverbanks by the California Department of Transportation to protect Highway 140. The National Park Service and Yosemite Motels also placed riprap in the Merced River channel to rebuild roads (e.g., Foresta Road) and protect buildings immediately adjacent to the river. Because stabilization of the riverbank began in the 1800s, the Merced River has been separated for decades from substantial portions of the floodplain in the Merced River Canyon. During spring runoff floods, this riprap serves to keep the channel from moving, and quickly conveys the water down to Lake McClure. During winter floods, bank stabilization prevents damage to dwellings and roads in the best-protected sections, but increases bank destruction where there is little or no bank stabilization.

No current actions are increasing or decreasing flood-related risk to human life. Between El Portal and Yosemite Valley, riprap has been placed in some locations along the north bank of the Merced River to protect the reconstructed El Portal Road. This riprap would have essentially no flood-related risk to life or property.

Reasonably foreseeable future actions that could have a potential cumulative beneficial or adverse effect on risk to human life and property during flood events are:

Cumulative effects of past, present, and reasonably foreseeable future actions would have both

beneficial (e.g., implementation of the Trailer Village Closure Plan) and adverse (i.e., increased development of overnight lodging units and offices within the floodplain at El Portal) impacts on human life and property during flood events. In El Portal, approximately 59 employee trailers with 68 employee beds at Hennessey’s Ranch (currently Trailer Village) would continue to be scheduled for removal from the 100-year floodplain. This action which occurs outside the scope of actions considered in the Final Yosemite Valley Plan/SEIS, is in accordance with the current provisions of the Trailer Village Closure Plan (NPS 1993b). Cumulative adverse impacts of these potential future projects on the floodplain hazard of the Merced River would be related to increased overnight use and facility development. In El Portal, potential overnight residents and hotel visitors would slowly increase from approximately 1,300 to about 1,600 beds because of the Yosemite Motel’s expansion and the Yosemite View Parcel Land Exchange. This represents an increase of approximately 25% in the number of people potentially affected during a flood.

Overall, the past, present, and reasonably foreseeable future actions listed above would have a long-term, moderate, and adverse effect on risk to human life and property due to the amount and type of new development planned within the floodplain. The total net effect of Alternative 3 would be moderate and beneficial, because overnight lodging/housing within the floodplain would be reduced (reducing flood-related risk to human safety), and mitigation would be implemented to reduce adverse effects on human safety and property associated with development/redevelopment within the floodplain. Effects associated with this alternative, in conjunction with other past, present, and reasonably foreseeable future cumulative actions, would be long-term, minor, and adverse, because potential flood-related impacts to human safety and property from cumulative actions outside the scope of the Final Yosemite Valley Plan/SEIS (e.g., increased overnight lodging within the floodplain in El Portal would increase flood-related risk to human safety and property) would outweigh the beneficial impacts of this alternative.

Wetlands were evaluated in the following locations for Alternative 3: Yosemite Valley, El Portal, Foresta, South Entrance, and Tioga Pass Entrance. The Wawona and Big Oak Flat Entrance locations have no wetlands; these areas are not discussed below. No actions are proposed in South Landing, Henness Ridge, Hazel Green, or Badger Pass in this alternative.

Wetland impacts would take place in the wetland types shown in table 4-59. The numbers of acres of impacts are estimated based on geographic information system analysis of acres of meadow and riparian vegetation types from the Yosemite Valley vegetation map (NPS 1994e). In Yosemite Valley, about 156 acres of wetlands would be restored, seven acres of new development in wetlands would take place, and 10 acres of redevelopment in potential wetlands would occur under this alternative. Therefore, there would be a net gain of 139 acres of wetlands in the Valley. Overall, this would be a long-term, major, beneficial impact on the size of wetlands in Yosemite Valley.

Table 4-59 Summary of Impacts by Wetland Type in Yosemite Valley
Wetland Types	Restoration (Beneficial Impact) (acres)	New Development (Adverse Impact) (acres)	Redeveloped (Potential Adverse Impact) (acres)
Palustrine Emergent	55	0	3
Palustrine Scrub Shrub	47	4	1
Palustrine Forest	47	3	6
Riverine Upper and Lower Perennial	7	0	0
Total	156	7	10

Restoration would take place at former Upper and Lower River Campgrounds, Camp 6, North Pines Campground, the Yosemite Lodge cabin area, River Protection Overlay, and highly valued resource areas at Housekeeping Camp, part of Lower Pines Campground, Backpackers and Group Campgrounds, the Art Activity Center, and Swinging Bridge Picnic Area.

New development in wetlands could take place on up to seven acres. Wetland delineation would be completed prior to the planning and design phase for Curry Village, where potential wetlands have been identified to maximize opportunities for wetlands avoidance and minimization of adverse impacts. If wetlands are present in the area, adverse impacts would be avoided during site design and minimized through design modifications to the greatest extent practicable. If potential adverse impacts on wetlands are disclosed in subsequent planning efforts, additional compliance documentation would be completed as appropriate.

Potential impacts to wetlands would require a Wetland Statement of Findings to be prepared in accordance with Director’s Order #77-1. Wetlands proposed for restoration by the Final Yosemite Valley Plan/SEIS would be counted toward the compensation of wetlands, if needed, in future compliance. A wetland delineation and a functional analysis would be included in each Statement of Findings. A U.S. Army Corps of Engineers 404 permit would be prepared as required.

About 10 acres of redevelopment in wetlands could occur under Alternative 3 (see table 4-59). The larger areas of redeveloped wetland would occur at Sentinel Picnic Area and Upper Pines Campground. Wetland delineation has been completed for Upper Pines Campground (Kleinfelder 1998). Redevelopment within wetland boundaries would be avoided in the Upper Pines Campground area. Wetland delineation would be completed prior to the design phase for the proposed Sentinel Picnic Area.

Redeveloped wetlands may be considered an adverse impact if the sites still qualify as wetlands. Procedural Manual #77-1, Section 5.4 states that "development activities proposed for wetland sites that have been modified or degraded as a result of human activities" (but still meet the wetland definition) are considered "new actions" subject to Director’s Order #77-1 and other statutes. Consequently, degraded wetlands should not be treated as preferred development sites simply because they are already in an impacted condition. Redevelopment in areas adjacent to wetlands would occur primarily at the former cabin area at Yosemite Lodge, the proposed road south of Yosemite Lodge, Yosemite Village, and Ahwahnee parking lot. There could be minor, beneficial effects on neighboring wetlands if water flows that sustain adjacent wetlands are improved in project design, and direct impacts would be minimized through site-specific design, resulting in negligible, adverse impacts.

No impact on the size of wetlands would occur in El Portal, Tioga Pass Entrance, South Entrance, or Foresta.

The integrity of wetlands would be improved by actions proposed in Alternative 3 in terms of the ratio of non-native to native species in palustrine emergent wetlands, and with restoration of soils, hydrology, and native species, and along the Merced River. The removal of roads and utilities in low lying areas would likely improve water flows, and restore naturally high water tables that sustain wetland conditions. The River Protection Overlay and restoration of former campgrounds to natural conditions would decrease foot traffic along the Merced River and allow riverside vegetation to become reestablished.

Foot traffic in the vicinity of Taft Toe would increase in nearby wetlands along the Merced River resulting in major, adverse impacts to wetlands in this area. The elimination of guided trail rides (though not private stock use) could benefit wetlands by eliminating associated manure, which could flow into wetlands and result in unnaturally high levels of nutrients that could harm wetland functions.

Road- and trail-related activities that could benefit wetland integrity include the removal of roads through Stoneman Meadow and the south part of Ahwahnee Meadow and restoration of the area.

Road- and trail-related activities that could have adverse impacts on wetlands include widening Southside Drive from El Capitan crossover to Curry Village to accommodate two-way traffic, constructing a multi-use trail from Swinging Bridge to El Capitan crossover, realigning Northside Drive along the southern perimeter of Yosemite Lodge, and constructing a new bridge across Yosemite Creek. These new roads and trails would directly impact some riverine and palustrine forest and scrub shrub wetlands at Sentinel Creek and along the Merced River and Yosemite Creek. All new roads, multi-use paved trails, and road widening would be designed to accommodate natural water flow patterns to mitigate direct and indirect effects. Under Alternative 3, the removal of roads from meadows and the implementation of the River Protection Overlay would have a long-term, major, beneficial impact on the integrity of wetlands in Yosemite Valley.

In El Portal, implementation of the River Protection Overlay and protection of existing wetlands at Hennessey’s Ranch through site design of new housing would minimize wetland impacts. Rebuilding the levee could have direct, adverse impacts on wetlands along the levee alignments, but impacts would be minimized by restoration of the riverine and palustrine forest wetlands between the levee and the river’s edge. Should parking be constructed near the El Portal Community Hall, site design would protect the historic river channel of palustrine forest wetlands. Overall, impacts on wetlands in El Portal are expected to be long-term, minor, and adverse, and would not affect the overall viability of wetlands in the area.

No impacts on the integrity of wetlands would occur in Badger Pass and Hazel Green as no actions are proposed in these areas under this alternative. Impacts to wetland integrity could occur in Foresta, through increased use of the area with relocation of stable operations to McCauley Ranch and addition of 14 houses for employees with an increased potential for establishment of non-native species in palustrine emergent wetlands. Wetlands adjacent to McCauley Ranch would be avoided through site design, and radiating impacts from increased nutrients and potential introduction of non-native plant species from the stables would be minimized by aggressive management of stock and waste feed. Potential increased foot traffic would have minor impacts on wetlands near the Tioga Pass Entrance.

Wetlands along the entire Merced River corridor in Yosemite Valley would be restored, reconnected, and protected from future degradation following removal of campgrounds and most facilities, including Upper and Lower Rivers, portions of Lower Pine, and sections of Housekeeping Camp, with major, beneficial impacts to riverine and palustrine forest and scrub shrub wetlands. Roads would be removed from or modified at Bridalveil, Stoneman, Ahwahnee, and Cook’s Meadows. The actions proposed in Alternative 3 would connect palustrine emergent wetlands in the Valley from Stoneman and Royal Arch Meadows to Bridalveil Meadow. This would be a long-term, major, beneficial impact on wetland connectivity in Yosemite Valley.

No additional adverse impacts on wetland connectivity would occur in El Portal, Foresta, South Entrance, or Tioga Pass Entrance.

Under Alternative 3 there would be a 139-acre net gain in the size of wetlands. Implementation of the River Protection Overlay and the removal of roads in Stoneman and Ahwahnee Meadows would substantially enhance the integrity of existing palustrine emergent wetlands. Natural processes such as flood interactions between the main Merced River channel and riverine wetlands, riparian borders of palustrine forest and scrub shrub wetlands, and palustrine emergent wetlands that are necessary to sustain healthy wetlands would be improved substantially. Wetlands in the vicinity of Taft Toe would be impacted by increased visitor use. The actions that are proposed in Alternative 3 would have a long-term, major, beneficial impact on the size, integrity, and connectivity of wetlands in Yosemite Valley. Minor, adverse impacts to wetland integrity would occur to out-of-Valley areas at El Portal, Foresta, and Tioga Pass Entrance with implementation of mitigation measures.

Past, present, and reasonably foreseeable future actions that could cumulatively impact wetlands are all considered to be long term.

Regional and parkwide planning efforts such as the Sierra Nevada Framework for Conservation and Collaboration (USFS); U.S. Forest Service management plans for adjacent wilderness; the Wilderness Management Plan Update (NPS); and the Fire Management Plan Update (NPS) could provide benefits to the size, integrity, and connectivity of wetlands. Cooperation among land management agencies would increase the opportunity to share common objectives and improve resource protection. These plans could also increase knowledge of resources and recreational use; they have the potential to have long-term, moderate, beneficial impacts on wetlands, though the proposed management direction has not been finalized. The Merced Wild and Scenic River Comprehensive Management Plan would affect wetlands through zoning and management designed to protect the river system and adjacent wetlands, with long-term, major, beneficial impacts.

The Tuolumne Meadows Water and Wastewater Improvements (NPS) project and the Mariposa Creek Pedestrian/Bike Path (Mariposa Co.) project are in the early planning stages. Until the scope and design of these projects is determined it is not possible to determine the extent of impacts on wetlands in these areas.

Other projects approved or planned for construction that could have beneficial effects on wetlands include campground rehabilitation projects in Tamarack, Yosemite Creek, Bridalveil, and Hodgdon Meadows Campgrounds, and the Merced River at Eagle Creek Ecological Restoration Project (Yosemite Valley). Erosion control and mitigation as a result of these projects could enhance and strengthen palustrine forest and palustrine scrub shrub wetlands. The Eagle Creek project would revegetate currently denuded riverbanks with benefits to palustrine forest and palustrine scrub shrub wetlands. The erosion control and restoration projects would have long-term, localized, and therefore minor, beneficial impacts on wetlands.

Projects approved or planned for construction that could have adverse effects on wetlands include the Yosemite View Parcel Land Exchange (NPS), University of California, Merced campus (Merced Co.), and the Hazel Green project. The Yosemite View Parcel Land Exchange could directly impact existing palustrine forest and palustrine emergent wetlands along the Merced River corridor. A wetland traverses the Hazel Green Ranch site, and could be impacted by radiating use, though proposed new development would not take place within the wetland corridor. The long-term direct impacts on wetlands would be moderate and adverse due to the relative rarity of undeveloped wetlands between the elevations of 1,000 and 3,000 feet and the relative importance of remaining wetland habitat in the Sierra Nevada. Foothill areas below about 3,300 feet appear to have the greatest loss of wetlands of any region in the Sierra Nevada (UC Davis 1996a) and are particularly important in terms of their productivity and diversity.

The actions that are proposed in Alternative 3 would amount to a net gain of 139 acres of wetlands in Yosemite Valley. Large-scale benefits to wetlands could take place as a result of regional and parkwide planning efforts such as the Sierra Nevada Framework for Conservation and Collaboration (USFS) and comprehensive restoration of wetlands within the River Protection Overlay of the Merced River Plan. Should substantial or full implementation of the actions included in these plans occur over time, long-term cumulative impacts on wetlands may, on balance, be moderate and beneficial. These regional plans are tempered by adverse impacts that include existing infrastructure that diverts water away from wetlands in Yosemite Valley, the potential direct loss of wetland habitat at the Yosemite View Parcel Land Exchange (NPS) at Hazel Green Ranch and at University of California, Merced campus (Merced Co.). When the impact of the past, present, and future actions are combined with the actions proposed in Alternative 3, there would be a moderate, beneficial impact on wetland size, integrity, and connectivity.

The following discussion identifies and characterizes the impacts to soils expected from implementation of Alternative 3. Impact intensities are based on the size, type, and disturbance history of the soil resources impacted. Soil resources are identified as highly valued resource (HVR), resilient (R) or other (O). The primary activities that would affect soil resources are discussed for each of the project areas. Generally, adverse impacts to soils would include a combination of soil removal, profile mixing, compaction, erosion, and contamination. Beneficial impacts would occur as a result of soil restoration. Construction-related impacts (such as compaction from equipment and erosion) would be expected to be short term and temporary, because they would be minimized through the use of Best Management Practices and would occur for a limited time. All other impacts are expected to be long term unless otherwise noted.

Approximately 305 acres would be affected by actions proposed under Alternative 3. Of this acreage, 144 acres would be highly valued resource soils, 122 more resilient soil, and 38 other soil types. Of the total area affected, 206 acres would be restored, while 98 acres would be associated with new development. Construction-related (short-term) impacts would be negligible to minor because Best Management Practices would be used to minimize erosion and to contain construction activities to the immediate area. Some minor discrepancies between acreages in the text and tables may occur due to rounding or differences in mapping sources, and because impacts less than 1 acre are not mentioned in the text. A summary of effects to soils is found in table 4-60.

Table 4-60 Summary of Soil Types Affected
Soil Type	Resource Type¹	Development Limitations²	Affected Area (acres)
Soil Type	Resource Type¹	Development Limitations²	Restored	Developed
101 Riverwash, 0-2%	HVR	F (frequent), SBE, HWT	9	—
102 Riverwash, 1-4%	HVR	F (frequent), SBE, HWT	—	—
104 Aquandic Humaquepts, 0-2%	HVR	F (frequent), HWT	5	—
105 Histic Haploaquols	HVR	HWT	—	—
151 El Capitan fine sandy loam, 0-2%	HVR	F (occasional), SBE, HWT (moderate)	66	—
152 Vitrandic Haploxerolls, 0-3%	O	F (occasional), D, LOS	—	—
201 Leidig fine sandy loam, 0-2%	HVR	F (occasional), HWT (moderate)	59	—
301 Vitrandic Haploxerolls, coarse, loamy, 0-2%	HVR	F (rare), HWT, LOS	—	—
401 Sentinel loam, 0-2 %	R	F (rare), LOS	—	24
412 River course	HVR	F	2	—
501 Miwok complex, 1-5%	R	F (rare), SBE	46	51
502 Miwok sandy loam, 0-3%	O	F (rare), SBE	—	—
504 Mollic Xerofluvents, 1-5%	O	F (frequent), SBE	1	10
551 Miwok — Half Dome complex, 5-15%	O	SE, LOS, D, C, AC	11	7
552 Mollic Xerofluvents, 5-15%	O	F (frequent)	—	1
590 Terric Medisaprist, 0-3%	HVR	F (occasional), HWT, SBE	—	—
601 Half Dome complex, 25-60%	O	SE, LOS, D, AC	2	3
602 Half Dome extremely stony sandy loam, 10-25%	O	SE, LOS, D, AC	1	2
610 Rubble land — Half Dome complex, 25-60%	O	SE, D, AC	—	—
620 Half Dome complex, warm phase, 25-60%	O	SE, LOS, D, AC	—	—
630 Rubble land — Half Dome complex, warm phase, 25-60%	O	SE, LOS, D, AC	—	—
701 Vitrandic Haploxerolls, 4-30%	R	SE (moderate), LOS	1	—
702 Vitrandic Xerochrept, 4-30%	HVR	SE (moderate), LOS	3	—
900 Rock outcrop	O	B	—	—
Total Area Affected			206	98

Approximately 33 acres would be impacted by actions proposed under Alternative 3: 17 of these acres would be restored (R=5, O=12); and 16 acres would be developed (R=8, O=8). Alternative 3 would have relatively equal impacts with respect to restoration and development. Most of the beneficial impacts associated with the restoration would occur on other soil types (551 Miwok — Half Dome complex). No highly valued resource soils would be restored. Beneficial impacts were evaluated as moderate because no highly valued resource soils would be restored. Development and redevelopment of lodging units, campgrounds, and the development of a new picnic area would have adverse effects on 16 acres. Approximately half of those impacts would occur on other soil types (551 Miwok — Half Dome complex). Development effects were evaluated as minor and adverse. Overall, the beneficial effects slightly outweigh the adverse effects, with a net result of negligible, beneficial impacts in Curry Village.

Approximately 49 acres would be affected by actions proposed under Alternative 3: 46 of these acres would be restored (HVR =23, R=22, O=1); and 3 acres would be developed (R=2, HVR=1). Nearly all of the impacts at Yosemite Lodge are related to restoration activities. Additionally, large portions of the soils to be restored (23 acres) are highly valued resource soils. Restoration activities would have a major, beneficial effect at Yosemite Lodge. The adverse impacts associated with building construction would affect only a small acreage of resilient soils; therefore, adverse effects were evaluated as negligible. The overall impact at Yosemite Lodge would be major and beneficial.

Just over 14 acres would be affected by actions proposed under Alternative 3: 14 of these acres would be restored (HVR =12, R=1, O=1); and less than 1 acre would be developed. Essentially all of the impacts at Yosemite Village would be beneficial because the development activities would be focused on areas that are currently developed. The largest portion of the restoration would occur on highly valued resource soil type 151 El Capitan fine sandy loam (8 acres). Overall, the proposed activities at Yosemite Village would have a moderate, beneficial impact on soil resources.

Approximately 54 acres would be developed by actions proposed under Alternative 3 (R=42, O=12). All of the activities proposed for west Valley would result in adverse impacts. Nearly all of these impacts would occur at Taft Toe as a result of parking facility construction. Resilient (401 Sentinel loams) and other soil resources would be primarily affected. Due to the relatively large area and type of soil resources affected, the overall impact would be moderate and adverse in the west Valley.

A total of 151 acres would be impacted by actions proposed under Alternative 3: 128 of these acres would be beneficially affected (HVR=109, R=17, O=2); and 24 acres would be developed (R=23, O=1). Beneficial impacts would be dominated by the restoration of highly valued resource soils. These effects are the direct result of the implementation of the River Protection Overlay, restoration of parts of the Lower Pines and North Pines Campgrounds, restoration of Camp 6, and the removal of roads from Stoneman and Ahwahnee Meadows. Restoration activities would result in major, beneficial impacts. Adverse impacts would occur on resilient soil types that are generally suitable to the proposed use. Adverse impacts were evaluated as being minor and adverse due to their size. Overall, the proposed activities at the campground areas would result in major, beneficial impacts on soil resources.

Transportation corridors such as multi-use paved trails and roadways have the potential to affect multiple soil types. Generally, trail construction would occur adjacent to existing linear corridors such as roads or utilities, or would be upgrades of existing informal trails. The impact of new trail construction would be adverse; however, the impact would be minor because the impacts would primarily be in linear segments of previously disturbed soils. New trails would be constructed to accommodate surface and subsurface water flow. Additionally, upgrades to existing trails would decrease erosion in high-use areas. Overall, the construction of new roads and trails would have minor, adverse impacts.

Soils information is limited for many of the out-of-Valley locations. The following discussion is based on the general soils information available or extrapolated from other local soil surveys. It is assumed that out-of-Valley impacts would likely occur on resilient soil resources, because the topographic features outside of the Valley tend to be less constricting than those in the Valley. Disturbance to highly valued resource soils would be avoided as practicable, to reduce the likelihood of impacts on highly valued resource soils. General Best Management Practices and design requirements would reduce potential impacts to other soils. The following discussion is based on the premise that the majority of adverse impacts would occur on resilient soil resources, where feasible.

The adverse impacts at El Portal would be related to the construction of employee housing facilities. Impacts would be similar to, but less than those described for Alternative 2, because large-scale parking facilities would not be planned under Alternative 3. Overall, the proposed actions at El Portal would mostly impact soil resources categorized as other, with a net moderate and adverse impact.

Impacts to soils in Foresta would occur if the National Park Service and concessioner stables are relocated to McCauley Ranch, and as a result of the reconstruction of employee beds destroyed in the 1990 A-Rock fire and the relocation of campsites for park-sponsored volunteer groups. However, impacts would be minor and adverse, because soils in these areas tend to be resilient and the area of impact would be relatively small.

Development and/or redevelopment of a visitor center near the existing entrance stations would result in adverse impacts to soil resources. The center would be developed adjacent to existing stations and, generally, would be located in areas that are suitable to the proposed use. The size of impact for each center would be relatively small in relation to the surrounding soil resources. The impact due to construction of visitor centers would be negligible and adverse.

Four out of the five areas evaluated would have overall beneficial impacts under Alternative 3, which proposes restoration of 206 acres and development of 98 acres. West Valley would have the largest adverse impact, largely due to construction of parking facilities at Taft Toe. This adverse impact is offset to a large extent by the restoration of 144 acres of highly valued resource soils, 47 acres of resilient soils and 15 acres of other soil resources. Additionally, the proposed developments are focused primarily on the use of resilient and other soil resources. Thus, the overall in-Valley impact of Alternative 3 would be moderate and beneficial.

The overall impact to out-of-Valley sites is relatively small under Alternative 3. The proposed activities are estimated to affect less than 40 acres, and would be focused on non-highly valued resource soils. The overall out-of-Valley impact would be negligible and adverse.

The actions under Alternative 3 would have moderate, beneficial impacts to soils in Yosemite Valley. Most of the adverse impacts would occur within the Valley and would be associated with the Taft Toe parking facility. The actions in Alternative 3 would focus restoration on highly valued resource soils and use primarily resilient soils for development. Actions out of Valley would have negligible, adverse impacts. Facility design and construction would use current technology and Best Management Practices to minimize development impacts. The sum of all impacts for Alternative 3 would be minor and beneficial.

The impacts of past, present, and reasonably foreseeable future areawide projects outside of the area would be the same as described under Alternative 2, minor and adverse. In relation to the expected impacts resulting from areawide projects, the beneficial impacts related to restoration under this alternative would be substantial since they would be the primary beneficial impacts on soil resources that would occur in the region. Thus, this alternative would serve to offset some of the adverse cumulative effects of other projects in the vicinity of the park. Therefore the cumulative impact of Alternative 3, in conjunction with other areawide projects, would be negligible and beneficial.

All impacts on vegetation identified through this analysis are considered long-term unless otherwise noted. Short-term impacts would occur during construction or implementation of actions. Based on the mitigation measures to be taken (see Vol. Ia, Chapter 2), all short-term impacts are expected to be negligible.

The plant communities within out-of-Valley areas do not directly relate to the grouped vegetation types defined for the Valley because of elevation, terrain, and species composition differences. For example, the dominant plant sp