| Table of Contents | Environmental Consequences | Alternative 1 | Alternative 2 |
| Part 1 | Part 2 | Part 3 | Part 4 | Part 5 | Part 6 |

The analysis of potential impacts from actions implemented under Alternative 2, Yosemite Village and Out-of-Valley Parking (El Portal, Badger Pass, and Hazel Green or Foresta), are presented in this section.

This analysis assesses 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).

YOSEMITE VALLEY HYDROLOGY

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, beneficial impact on hydrology and floodplain values.

Alternative 2 would allow restoration of some of the oxbows and cut-off channels that once existed in the Camp 6 area, because the River Protection Overlay would be restored and redevelopment would occur outside the River Protection Overlay. 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 Camp 6 area. Restoration actions at Camp 6 would result in localized, long-term, moderate, and beneficial impacts on hydrology and the floodplain values.

The Camp 6 parking facility would be situated within a portion of the floodplain that could experience floodwater velocities up to 3 feet per second, and floodwater depths exceeding 5 feet in places, as was observed during the January 1997 flood. This parking facility, although in an area of low relief and not likely to divert flood flow due to obstructions, could impede the river’s ability to naturally migrate and change course during the extreme flood events. For example, an asphalt pavement surface could hinder the formation of natural flow channels or accelerate surface soil erosion once the asphalt surface and underlying base material are scoured and removed by high-velocity flood waters. A flat surface parking facility could also reduce the area available to the river for sediment deposition and new bank slope formation. In addition, riverbank stability (soils compaction and vegetation loss) could be reduced due to the radiating impacts associated with the increased concentration of visitors. Overall, development of a parking facility in the Camp 6 area could result in localized, long-term, moderate, adverse impacts on hydrology and floodplain values.

The transit center at Yosemite Village would be constructed outside of the 100-year floodplain, but the concentration of visitors would have radiating impacts on 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 existing three structures at Ahwahnee Row that are located in the 100-year floodplain would continue to have a long-term, localized, adverse impact on floodplain values by impeding 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, 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 removal of Sugar Pine Bridge (and possibly Stoneman Bridge) would be noticeable as the erosional and scour features 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. The possible removal of Stoneman Bridge and restoration of the riverbank (vegetation, bank slope, and channel width) would be a localized, long-term, major, 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.

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

The removal of the Happy Isles footbridge that is in imminent danger of failure, and construction of a newly designed bridge that would have a smaller footprint in the river channel and accommodate flood flow, would be a moderate, beneficial impact to hydrology and floodplain values. Local, short-term, minor, and adverse impacts to hydrology may occur as a result of construction activities in the main channel.

The possible reconstruction of Swinging Bridge would have long-term, localized, minor, and beneficial impacts on the Merced River’s hydrology, because the bridge abutments would be removed from the river channel (although some piers would remain in the river). Local, short-term, minor, and adverse impacts to hydrology would occur during reconstruction due to construction 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, and adverse impacts to hydrology may occur during removal due to construction 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 normal high water and would minimally impact hydrologic processes. This would result in a long-term, minor, adverse impact on hydrology. Local, short-term, minor, and 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 by 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, and beneficial impact to 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 Act Section 7 determination, would be necessary before this segment of road can be reconstructed.

YOSEMITE VALLEY QUALITY

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 construction and maintenance of visitor use facilities. 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 area and Swinging Bridge Picnic Area and restoration to natural conditions would reduce a source of nutrients, coliform, turbidity, and other water pollutants to the Merced River. Overall, actions to implement the River Protection Overlay would result in a regional, long-term, moderate, beneficial impact on water quality by removing development immediately adjacent to the Merced River.

The removal of parking spaces from Curry Orchard, Yosemite Falls, the concessioner stable, Stoneman Meadow, 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 to the surface soils and pavement a variety of heavy metals, petroleum-based products, and other chemicals, including asbestos and ethylene glycol. Some fraction of these chemicals can migrate from their source, carried by surface-water runoff, to drainages that eventually reach the river or smaller tributaries. A formalized parking facility would be established at Camp 6, and a transit facility at Yosemite Village; these facilities would have stormwater treatment controls incorporated into their design (possible treatment methods include sand filters, underground water collection and treatment tanks, or oil/water separators). Replacing the existing parking areas listed above with a formalized parking facility at Camp 6 would improve water quality by improving treatment of stormwater runoff, 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, and beneficial impact on water quality by reducing non-point source pollution.

EL PORTAL HYDROLOGY

As a result of a U.S. Army Corps of Engineers study (1998), Alternative 2 proposes extending and increasing the height of the flood protection levee (hereafter, "levee") in El Portal’s Hennessey’s Ranch area, 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 bank due to increased employees living in the area. These radiating impacts would have a long-term, minor, adverse impact.

Alternative 2 proposes construction of two pedestrian bridges 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, and adverse impacts on the river’s hydrology and floodplain values. Local, short-term, minor, adverse impacts on hydrology may occur during construction due to construction activities in the main channel.

EL PORTAL WATER QUALITY

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). The removal of the bulk fuel storage facility would remove the risk of fuel releases during flood events. Actions to implement the River Protection Overly and remove the bulk fuel storage facility would have a regional, long-term, moderate, beneficial impact. 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 to 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 increased development in El Portal on water quality would be localized, long-term, minor, and adverse, due to increased non-point source pollution resulting from increased development.

WAWONA HYDROLOGY

Construction of employee housing in Wawona would be outside of the 100-year floodplain, approximately 1,000 feet away from the South Fork Merced River. Radiating impacts to the river due to increased numbers of employees accessing the river would reduce bank stability and result in localized, long-term, negligible, adverse impacts on hydrology and floodplain values.

WAWONA WATER QUALITY

Actions to implement the River Protection Overlay would reduce discharge of non-point source pollutants into the river by providing a buffer area where future development is constrained. Water quality could be adversely impacted at the new employee housing by runoff associated with increased parking spaces, although this impact would be mitigated by non-point source pollution controls at large paved areas. Wastewater from all new buildings would be connected to the existing sanitary sewage system and would meet all applicable water treatment requirements. The impacts of Alternative 2 on water quality in Wawona would be localized, long-term, minor, and adverse.

HAZEL GREEN HYDROLOGY AND WATER QUALITY

The project site at Hazel Green is located near the headwaters of Bull Creek, which drains into the North Fork of the Merced River, and Hazel Green Creek, which drains into Crane Creek. The hydrology of Hazel Green Creek and surface water runoff are the only pertinent hydrologic processes. Alternative 2 proposes construction of a parking facility, which would have a localized, long-term, minor, adverse impact on hydrology, resulting from reduced ground cover and potentially increased runoff. Construction of a parking facility would increase non-point source pollution, which would be mitigated through stormwater pollution controls, and would have localized, long-term, minor, adverse impacts on water quality.

FORESTA HYDROLOGY AND WATER QUALITY

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. Alternative 2 proposes construction of a parking facility, placement of a Volunteers-in-Parks (depending on the outcome of the wilderness feasibility study) campground, construction of 14 houses, and the possible relocation of the National Park Service stable to McCauley Ranch. These actions would have a localized, long-term, negligible, adverse impact to 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.

BADGER PASS HYDROLOGY AND WATER QUALITY

The project site at Badger Pass has several springs, seeps, and wetlands that form the headwaters of Grouse Creek. The hydrology of these headwaters and surface water runoff are the only pertinent hydrologic processes. Alternative 2 proposes construction of a parking facility that will be approximately the same size as the current parking lot and expanded visitor use facilities. Alternative 2 would have a localized, long-term, minor, adverse impact on hydrology resulting from reduced ground cover, and potentially increased runoff associated with the expanded visitor use facilities. Alternative 2 would have a localized, long-term, minor, adverse impact on water quality resulting from increased non-point source pollution due to use of the parking area for longer periods of time.

The diverted runoff could impact the water quality of the Grouse Creek headwaters by introducing low concentrations of petroleum materials and sediments from the parking lot during periods of high runoff from precipitation and snow melt. This could represent a regional, long-term, adverse impact on water quality.

BIG OAK FLAT, TIOGA PASS, AND SOUTH ENTRANCE
HYDROLOGY AND 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. Alternative 2 proposes construction of a visitor center and associated visitor use facilities that would reduce ground cover and potentially increase 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, and adverse impact to water quality resulting from increased non-point source pollution associated with development.

CONCLUSION

The collective actions of this alternative have regional, long-term, moderate, beneficial impacts to 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 one and possibly two bridges, Cascades Diversion 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.

COMULATIVE IMPACTS

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

Past Actions

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.

Present Actions

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

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:

• The Merced River at Eagle Creek Ecological Restoration Project (NPS)

• Merced Wild and Scenic River Comprehensive Management Plan (NPS)

• Yosemite Wilderness Management Plan Update (NPS), which will address land management issues within the wilderness

• Fire Management Plan Update (NPS)

• Potential Land Use and Management on Lands Adjacent to Yosemite National Park (Sierra Nevada Framework for Conservation and Collaboration).

• Several transportation-related projects (e.g., Yosemite Area Regional Transportation System [YARTS]), which have the general goals of increasing transportation options and reducing reliance on automobiles in the area

• Replacement/Rehabilitation of Yosemite Valley Sewer Line (NPS)

• South Fork Merced River Bridges Replacement (NPS)

• Bridalveil Horse Camp Rehabilitation (NPS)

• Yosemite Creek Campground Restoration (NPS)

• Wawona Campground Rehabilitation (NPS)

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 on water resources include:

• Merced River Canyon Trail Acquisition (BLM)

• Mariposa Grove Roadway Improvement and Giant Sequoia Restoration (NPS), which would remove parking from the Lower Mariposa Grove of Giant Sequoias, restore the area, and realign the intersection at the South Entrance Station.

• Rogge—Ackerson Fire Reforestation (Tuolumne Co.), which would improve slope stability and reduce sedimentation by reforesting 5,000 acres; however, activities could also adversely impact water quality by burning, tilling, and herbicide application.

• A-Rock Reforestation (USFS, Stanislaus), which would improve slope stability and reduce sedimentation by reforesting 4,500 acres; however, activities could also adversely impact water quality by burning, tilling, and herbicide application.

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 future projects that could have a net adverse impact on water resources include:

• The Yosemite View Parcel Land Exchange, El Portal (NPS)

• Merced River Canyon Trail Acquisition (BLM)

• Yosemite Motels Expansion, El Portal (Mariposa Co.)

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

Beneficial impacts on 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, and beneficial impact on water resources. The actions of this alternative would have a long-term, minor, and 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 4-26; 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.

YOSEMITE VALLEY

Cascades Diversion Dam

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.

Concessioner Stable Area

A moderate, beneficial impact would result from the removal of houses and tent 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.

Housekeeping Camp

The removal of 164 housekeeping units and the retention of 84 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 used during the winter flood season.

Yosemite Village

Removal of the Concession Headquarters and Indian Creek employee housing (14 employee beds) from and, if necessary, raising the floor elevations of three Ahwahnee Row houses above 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. As designs are developed for the Yosemite Village for parking, visitor services and transit operations, new structures would be located out of the floodplain, where possible. An evacuation and safety plan would be developed to protect people during flood events. With these mitigation measures and in accordance with National Park Service Floodplain Management Guideline, there would be a minor risk to both human safety and property.

Yosemite Lodge Area

Removal of the Superintendent’s House (Residence 1) and 5 motel units from the 100-year 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).

EL PORTAL

Village Center

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 from 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 working within the floodplain and hazardous material stored in 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 for redevelopment 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 this mitigation measure in place, there would be a minor adverse impact.

Hennessey’s Ranch

The removal of 68 employee beds and the construction of 657 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.

WAWONA

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

CONCLUSION

Beneficial impacts in Yosemite Valley would include removal from the floodplain of 164 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), and 657 employee beds at Hennessey’s 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 2 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.

CUMULATIVE IMPACTS

The impacts of past, present, or reasonably foreseeable future projects to flood hazard discussed herein are based on analysis of 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.

Past Actions

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.

Present Actions

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

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

• El Portal, Trailer Village Closure (NPS)

• Yosemite Motels Expansion, El Portal (Mariposa Co.), (approximately 148 new hotel units)

• Yosemite View Parcel Land Exchange (NPS)

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 proposed 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, 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 2 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 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.

In this section, wetlands were evaluated in the following locations: Yosemite Valley, El Portal, Tioga Pass Entrance, South Entrance, Hazel Green, Badger Pass, and Foresta. The South Landing, Henness Ridge, Wawona, and Big Oak Flat Entrance locations do not have wetlands; these areas are not discussed below.

SIZE

Yosemite Valley

Wetland impacts would take place in the wetland types shown in table 4-27. The numbers of acres of impact are estimated based on geographic information system analysis of acreages of meadow and riparian vegetation types from the Yosemite Valley vegetation map (NPS 1994e).

A net gain of approximately 118 acres of wetland would take place under Alternative 2 in Yosemite Valley. About 141 acres of wetland would be restored, 12 acres of new development in wetlands would take place, and 11 acres of redevelopment in degraded wetlands could take place. Overall, this would be a long-term, major, beneficial impact on the size of wetlands in Yosemite Valley.

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

New development in wetlands could occur at the proposed Yosemite Village parking lot, at Curry Village (in maple-dominated drainages), and at Upper Pines Campground. Wetland delineation has been completed for Upper Pines Campground (Kleinfelder 1998). Four wetland tributaries to the Merced River and four small wetlands (less than 0.33 acre) lie within the Upper Pines Campground, would be avoided during all new construction.

Wetland delineation would be completed prior to the design phase for the proposed Yosemite Village day-use parking area and at Curry Village for lodging and employee housing. This would take place well in advance of the project design phase to maximize opportunities for wetland avoidance and minimization of adverse impacts. If potential adverse impacts on wetlands are disclosed in subsequent planning and design 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.

Up to 11 acres of redevelopment in wetlands could occur under Alternative 2 (see table 4-27). The larger areas of redeveloped wetland would occur at Sentinel Picnic Area and Upper Pines Campground. Wetland delineation would be completed prior to the design phase for the proposed Sentinel Picnic Area. Wetland delineation has been completed for Upper Pines Campground (Kleinfelder 1998). Redevelopment within wetland boundaries would be avoided in the Upper Pines Campground 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.

Several smaller potential wetlands could be impacted by redevelopment. These occur in the proposed campground near Curry Orchard, Yosemite Village parking, and the proposed amphitheater at the concessioner stable. Wetlands at the Curry Orchard area and concessioner stable area have been delineated (Kleinfelder 1998). Wetlands would be avoided in redevelopment of campground and amphitheater areas. Potential wetlands at the proposed Yosemite Village parking site would be addressed by future compliance.

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. Minor, adverse impacts would occur on neighboring wetlands due to altered water flows that sustain adjacent wetlands. These impacts would be minimized through site specific design resulting in negligible, adverse impacts.

Out-of-Valley Areas

At Hazel Green, a small palustrine scrub shrub wetland that covers less than a half-acre would be impacted by road and parking lot construction. This wetland, the headwaters of Hazel Green Creek, has been manipulated to concentrate flows entering a culvert under the Big Oak Flat Road. Impacts to this wetland would be addressed in detail by subsequent compliance.

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

INTEGRITY

Yosemite Valley

The integrity of wetlands would be improved by actions proposed in Alternative 2 in terms of the ratio of non-native to native species in palustrine emergent wetlands and with restoration of riverine and palustrine forest species 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 native wetland vegetation. 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.

The elimination of guided trail rides (though not private stock use) would indirectly benefit wetlands by eliminating associated manure, which could flow into wetlands and result in unnaturally high levels of nutrients.

Road- and trail-related activities that would directly 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 would have indirect, adverse impacts on wetlands include redesigning Southside Drive from El Capitan crossover to Curry Village to accommodate two-way traffic, constructing a multi-use paved 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 multi-use paved trails would directly affect some riverine and palustrine forest and scrub shrub wetlands at Sentinel Creek and along the Merced River. All new roads, multi-use paved trails, and road widening would be designed to accommodate natural water flow patterns to mitigate indirect effects.

Under Alternative 2, the removal of roads from palustrine emergent wetlands and riverine and palustrine forest and scrub shrub wetlands within the River Protection Overlay would have a long-term, major, beneficial impact on the integrity of wetlands in Yosemite Valley.

Out-of-Valley Areas

In El Portal, implementation of the River Protection Overlay and protection of existing wetlands at Hennessey’s Ranch would minimize wetland impacts. Rebuilding the levee could have direct, adverse impacts on wetlands along the levee alignment. These 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 wetland. 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.

At Hazel Green, a small palustrine scrub shrub wetland that is less than half an acre in size could be directly affected by construction of an access road to Hazel Green Ranch and a day-use parking area. Impacts on this wetland would be minor and adverse and subsequent site-specific compliance and site design would minimize impacts to the extent possible.

New indirect impacts at Badger Pass, South Entrance, and Tioga Pass Entrance on adjacent wetlands could occur as a result of heavy foot traffic. Foot traffic would be directed away from wetlands, though some additional foot traffic is still expected in the wetland area. This would be a minor, adverse impact on adjacent wetlands.

If Hazel Green is not chosen as the out-of-Valley parking area on the Big Oak Flat Road corridor, parking would instead be constructed at Foresta. A one and one-half acre artificial palustrine scrub shrub wetland (in an old borrow pit), is directly adjacent to the proposed parking site and is expected to be impacted by radiating foot traffic. This would be a long-term, minor, adverse impact on wetlands in Foresta with implementation of appropriate mitigation measures (Chapter 3, Vol. IA). Wetlands adjacent to McCauley Ranch would be avoided in site design for the relocation of stable operations to Foresta, and potential radiating impacts of nutrients and non-native plant species from the stables would be minimized by aggressive management of stock and waste feed.

CONNECTIVITY

Yosemite Valley

Under Alternative 2, the entire riparian corridor of riverine, palustrine forest, and palustrine scrub shrub wetlands along the Merced River, with the exception of Camp 6, would be restored with removal of Upper and Lower Rivers, Lower Pine, and North Pine Campgrounds, reconnecting these areas with adjacent palustrine emergent wetlands, and protecting the corridor from future degradation. Roads would be removed from Stoneman and Ahwahnee Meadows . This would be a long-term, major, beneficial impact on wetland connectivity in Yosemite Valley.

Out-of-Valley Areas

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

CONCLUSION

Under Alternative 2 there would be a 118-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 wetlands. A wetlands corridor would be recreated in the center of the Valley floor from the east Valley to Bridalveil Meadow, with the main exception of Camp 6. This would enhance natural processes such as flood interactions between the main Merced River channel, riparian borders, and meadows that are necessary to sustain healthy wetlands. The actions proposed in Alternative 2 would have a long-term, major, beneficial impact on the size, integrity, and connectivity of wetlands in Yosemite Valley. Minor, adverse impacts to wetland size and integrity would occur to out-of-Valley areas at El Portal, Hazel Green, Badger Pass, South Entrance, Tioga Pass Entrance, and potentially Foresta, with implementation of mitigation measures.

CUMULATIVE IMPACTS

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 stages of planning. 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 localized, long-term, 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 Ranch (Mariposa Co.) project. The Yosemite View Parcel Land Exchange could directly impact existing palustrine forest and palustrine emergent wetlands along the Merced River corridor. A wetland zone 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 1996) and are particularly important in terms of their productivity and diversity.

These areawide projects (as described in Vol II, Appendix H), in conjunction with the impacts of the No Action Alternative, would have overall minor, adverse impacts on wetlands in the area. All of these impacts would be long term.

The actions proposed in Alternative 2 would amount to a net gain of 118 acres of wetlands in Yosemite Valley. When the impacts of the past, present, and reasonably foreseeable future actions are combined with the actions proposed in Alternative 2, impacts on wetland size, integrity, and connectivity would be moderate and beneficial. This is mainly due to the relative rarity of wetland habitat in the Sierra Nevada today, and the large-scale and comprehensive restoration of wetlands in Yosemite Valley and regional and parkwide planning efforts such as the Sierra Nevada Framework for Conservation and Collaboration (U.S. Forest Service) and the Merced Wild and Scenic River Comprehensive Management Plan.

The following discussion identifies and characterizes the soils impacts expected from implementation of Alternative 2. Impact intensities are based on the size, type, and disturbance history of the soil resources impacted. Soil resources are identified as highly valued resources (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.

YOSEMITE VALLEY

Approximately 246 acres would be affected by actions proposed under Alternative 2: of this acreage, 136 acres are highly valued resource soils, 86 acres are resilient soil types, and 24 acres are other soils. Proposed restoration would occur on 177 acres, while the remaining impacted acres would be associated with new development. Acreages are calculated with the parameters used in the Yosemite Valley soil survey (SCS 1991). Some discrepancies between acreages in the text and the tables may occur due to rounding, differences in mapping sources, or because impacts less than 1 acre were not mentioned in the text. Construction-related (short-term) impacts would be negligible to minor since Best Management Practices (see Vol. Ia, Chapter 2, Soil Mitigation) would be utilized to minimize erosion and contain construction activities to the immediate area. A summary of affected soils is found in table 4-28.

Curry Village

Approximately 27 acres would be affected by actions proposed under Alternative 2: 11 of these acres would be restored (R=3, O=8); and 16 acres would be developed (R=8, O=8). Restoration activities would result in a moderate, beneficial impact on soil resources, because 8 acres of other soils would be restored. Development activities related to lodging redevelopment would result in moderate, adverse impacts because they would affect small areas of resilient and other soils. Other development activities would have negligible, adverse impacts because they would be relatively small and would generally affect previously disturbed sites. The overall impact to soil resources at Curry Village would be negligible and adverse.

Yosemite Lodge

Approximately 54 acres would be affected by actions proposed under Alternative 2: 48 of these acres would be restored (HVR=23, R=24, O=1); and 6 acres would be developed (R=5, O=1). Restoration of the floodplain area between the Yosemite Lodge and the Merced River would result in major, beneficial impacts to soil resources by restoring highly valued resource soils. Construction activities, such as those required for lodging units and the new bridge south of the Yosemite Creek Bridge, would have negligible, adverse impacts since these activities would be concentrated on resilient soils. The overall impact to soil resources at Yosemite Lodge would be major and beneficial.

1. HVR=Highly valued resource soil, R=Resilient soil, O=Other soil (non-HVR and non-resilient)
2. F=Flooding, SBE=Stream Bank Erosion, SE=Slope Erosion, HWT=High Water Table, D=Doughty (low water holding capacity), LOS=Loss of Organic Surface, C=Compaction, AC=Active Colluvium, B=Bedrock Curry VillageSource: Soil Survey of Yosemite National Park, Yosemite Valley, California (SCS 1991).

Yosemite Village

Approximately 20 acres would be affected by actions proposed under Alternative 2: 6 acres of these would be restored (HVR=5, O=1); and 14 acres would be developed (HVR=8, R=6). Restoration activities would occur on highly valued resource and other soil types. The net impact of these activities would be minor and adverse. The light fleet vehicle maintenance facility relocation to the National Park Service maintenance area would impact resilient soils that were previously disturbed. Other construction activities, such as the visitor center and firehouse, would impact undisturbed resilient and highly valued resource soils. The net effect of construction activities would be minor and adverse. Thus, the overall beneficial and adverse effects within Yosemite Village generally offset each other based on area and types of soils impacted, resulting in a net negligible and adverse impact.

West Valley

Approximately 12 acres would be adversely affected by actions proposed under Alternative 2 (R=7, O=5). Adverse effects would be primarily related to the construction of the North American Wall Picnic Area, and possible construction of a traffic check station near the El Capitan crossover. Both of these activities would occur on previously undisturbed resilient or other soil resources. Therefore, the overall effect of activities planned for West Yosemite Valley would be minor and adverse.

Campgrounds

Approximately 138 acres would be affected by actions proposed under Alternative 2: 114 of these acres would be restored (HVR=102, R=11, O=1); and 24 acres would be developed (R=23, O=1). The proposed project would have major, beneficial effects on soil resources due to the restoration of a large area of highly valued resource soils. A large portion of this acreage is related to the restoration of the 150-foot River Protection Overlay, campground removal at Upper and Lower River, and North Pines, and the restoration of the Swinging Bridge Picnic Area. Removal of the road from Sentinel Meadow would also have a beneficial impact by providing an opportunity to restore subsurface flow, thereby restoring historic soil properties. Adverse impacts are related to the development of new campground areas. Nearly all of the proposed areas for new campgrounds would impact resilient soil resources by limited amounts of compaction and erosion. Generally, the effects of campground development are less disturbing to soil resources than other construction activities. Thus, although the area of effect is relatively large (24 acres); the actual soil disturbance area would be much less extensive and would be reversible. Adverse effects due to campground development are expected to be minor and adverse. The overall impact within the campground area would be major and beneficial.

Roads and Trails

Transportation corridors such as multi-use paved trails and roadways have the potential to affect several 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 yet 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.

OUT-OF-VALLEY

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 primarily occur on resilient soil resources, because the topographic features outside of the Valley tend to be less constricting compared to those in the Valley. Disturbance to highly valued resource soils would be avoided as practicable, serving 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. Thus, the following discussion is based on the premise that the majority of adverse impacts would occur on resilient soil resources, where feasible.

El Portal

Most all of the impacts at El Portal would be long term and adverse. Adverse impacts would be related to the construction of parking facilities and employee housing. Beneficial impacts would be related to the removal of the commercial bulk fuel facility. Soils within the El Portal area tend to be susceptible to mass movement and erosion, and have substantial development limitations. Therefore, Best Management Practices and other mitigation measures described in Vol. Ia, Chapter 2, Soil Mitigation, would be implemented to minimize erosion and soil movement. Due to the size of the proposed activities and the limited space available for construction, this alternative would have a moderate, adverse impact on soil resources in the El Portal area.

Badger Pass

The soils at Badger Pass are appropriate for development, provided that Best Management Practices are incorporated into the construction and design. Potential problems tend to be associated with moderate to steep slopes and erosion control. Construction of the parking facility would result in locally minor, adverse impacts given it is currently used as parking.

Hazel Green

Most of the soils at Hazel Green are classified as resilient or other. Soils along the creek are highly valued resources; however, impacts in the riparian area would not be proposed. Construction of the parking facility would require a relatively large area and would result in moderate, adverse impacts.

Foresta

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.

If out-of-Valley parking does not occur at Hazel Green, additional soil disturbance would occur at Foresta due to construction of day-visitor parking. This parking facility would result in moderate, adverse impacts to soils.

Wawona

The soils within the Wawona area have mostly minor limitations for structures. Construction of housing facilities would occur on mostly resilient soils that are suitable for this use. Impacts at Wawona would be expected to be minor and adverse.

Entrance Stations

Development and/or redevelopment of visitor centers near the existing entrance stations would result in adverse impacts to soil resources. The centers 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 facility would be relatively small. The impact due to construction of visitor centers would be negligible and adverse.

CONCLUSION

Beneficial impacts on approximately 177 acres would be associated with restoration activities, including removal of structures, facilities, and campgrounds in Yosemite Valley. Most restoration activities would occur on highly valued resource soils, with 128 acres of restoration. Most of the adverse impacts in this alternative would be within heavily trafficked areas or adjacent to previously developed areas. The affected series are primarily resilient soil types (48 acres) with physical attributes that generally support the type of projects proposed in Alternative 2, without major management requirements. Eight acres of highly valued resource soils would be impacted by new development. The areas of disturbance are fairly localized with a very low net loss of previously undisturbed soil acreage. The net Valley impact of Alternative 2 would be moderate and beneficial.

Approximately 80 acres would be impacted by out-of-Valley projects; use of erosion controls during construction, and designed engineering controls would reduce, but not eliminate, long-term impacts in these soils outside of the Valley. Proper use of engineering controls and mitigation measures would result in an overall moderate, adverse impact to soils outside of the Valley.

The summary of all impacts resulting from actions proposed in Alternative 2 would be moderate and beneficial within Yosemite Valley, and moderate and adverse outside of the Valley. Alternative 2 would include a large amount of restoration within Yosemite Valley and would result in a greater beneficial impact to soils than the No Action Alternative. Although some facilities would be relocated outside of the park, it is expected that the relocations would use less sensitive resources than are currently being affected in the Valley. Furthermore, facility design and construction would utilize current technologies and Best Management Practices to minimize impacts. Out-of-Valley impacts would be locally moderate and adverse, but would be focused on resilient soil resources at all locations except for El Portal. Thus the overall impact for Alternative 2 would be minor and beneficial.

CUMULATIVE IMPACTS

Actions outside Yosemite National Park generally do not impact the same soil types as those found within the Valley, because soil types vary by geographical location. Therefore, the other present and reasonably foreseeable future projects considered to possibly have a cumulative impact on soils must occur in proximity to the park. For purposes of this evaluation, projects within five miles of the park were considered to have a potential effect on soil types consistent with those found in the park. These projects include:

• Replacement/Rehabilitation of Yosemite Valley Sewer Line (NPS)

• Yosemite Motels Expansion, El Portal (Mariposa Co.)

• Evergreen Lodge Expansion (Tuolumne Co.)

• Evergreen Road Improvements (multi-agency, see Appendix H)

• Yosemite West Rezone for 55 Acres (NPS)

• Tuolumne Meadows Development Concept Plan (NPS)

• Tuolumne Meadows Water and Wastewater Improvements (NPS)

• Hodgdon Meadow Campground Rehabilitation (NPS)

• Hodgdon Meadow Water and Wastewater Treatment Improvements (NPS)

Each of the above projects considered as having cumulative impacts has the potential to produce further soil disturbances. These disturbances would include erosion and compaction associated with development, such as the expansion of the Evergreen Lodge and Hotels in El Portal. Projects in Tuolumne Meadows may impact highly valued resource soils that are susceptible to erosion. While projects such as the Replacement/Rehabilitation of Yosemite Valley Sewer Line (NPS) may have beneficial effects on water resources, their effect on soils would generally be adverse as a result of soil mixing and compaction. Overall, the projects outside of the park that may have cumulative impacts are small in scope, compared to the total area of the region. Additionally, the impacts associated with those projects would be minimized through the use of Best Management Practices, as required by local, state, and federal regulations. For these reasons, the impacts expected to occur outside of the Final Yosemite Valley Plan/SEIS would be long-term, minor, and adverse.

As described above, the overall impact of Alternative 2 would be minor and beneficial. Consequently, the cumulative impacts that would result from Alternative 2, in conjunction with the expected impacts resulting from present and reasonably foreseeable future projects, would be negligible and beneficial. The beneficial impacts resulting from Alternative 2 restoration actions would be quite substantial because they are the primary beneficial impacts on soil resources that would occur. Thus, implementing actions proposed under Alternative 2 would serve to offset some of the adverse cumulative effects of other projects in the vicinity of the park.

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 (see Vol. Ia, Chapter 2) to be taken, all short-term construction-related impacts are expected to be negligible.

Plant communities within the out-of-Valley areas do not directly related to the grouped vegetation types defined for the Valley due to elevation, terrain, and plant composition differences. Therefore, plant communities in out-of-Valley areas are described separately from Valley vegetation types.

YOSEMITE VALLEY

The actions proposed under Alternative 2 would result in a net gain in all vegetation types, except upland and other (orchards, bare ground, lawns) communities. Table 4-29 summarizes the total areas of each vegetation type that would be adversely and beneficially impacted by Alternative 2. Minor discrepancies in totals between table and text are due to rounding impacts to the nearest acre. It should be noted that the size of the area affected was only one of the factors used to evaluate impact magnitude. The continuity, productivity, structure, and diversity of the vegetation type are also factors considered in this impact analysis.

Note: Acreages presented in this table do not include impacts from linear features such as roads and trails. These impacts are discussed separately in the text.

Approximately 100 acres of existing developed or disturbed areas within the Valley would be converted back to natural vegetation through the restoration actions described below. These actions would have a major, long-term beneficial impact to the continuity of Yosemite Valley’s plant communities.

Due to their linear nature, transportation corridors such as multi-use paved trails and roadways would have the potential to affect multiple vegetation types. Therefore, rather than repeating this discussion under each vegetation type below, road and trail impacts are described here. Under this alternative, there would be new paved trail segments constructed. Generally, these trails would either parallel existing linear corridors such as roads or utilities or would be located within areas that have been previously disturbed by past actions or social trails. The purpose of these new trail segments would be to provide connections to existing paved trails to improve the overall multi-use trail network for alternative modes of transportation through the Valley, which would reduce the need for cars. The impact of new trail construction would be adverse to vegetation; however, the impact would be minor to moderate given the small amount of vegetation impacted (9 acres). The impacts would occur primarily in previously disturbed uplands (non-highly valued resource), and they would be designed to avoid as many mature trees as possible as well as to accommodate surface and subsurface water flow. The new trails would, however, increase fragmentation. Similarly, the three segments of realigned roadway and the one widened roadway would also have minor, adverse impacts on vegetation (3 acres). The new bridge over Yosemite Creek would impact a small area of California black oak vegetation (0.5 acre) adjacent to the existing bridge. The actions would result in a moderate adverse impact to this community.

Restoration of meadow (3 acres) and California black oak (0.5 acre) habitat would occur as a result of road removal within Ahwahnee and Stoneman Meadows and the turnout lanes at Northside Drive through El Capitan Meadow and Southside Drive near Bridalveil Fall. The impact on these vegetation types would be moderate and beneficial because they are both highly valued resource types.

Overall, the road and trail impacts would have a negligible to minor, adverse effect on vegetation because the adverse effects would generally be to previously disturbed, non-highly valued resource types. The beneficial effects would restore highly valued resource types, compensating for some of the adverse impact.

Upland Communities

Upland vegetation makes up the largest group of vegetation types within Yosemite Valley. Alternative 2 actions would result in the restoration of approximately 15 acres of existing upland vegetation types in the Valley and the development of roughly 49 acres of currently undeveloped upland types. The overall impact of this alternative on upland communities would be minor and beneficial due to improved conditions of upland vegetation through re-introduction of fire and decreased plant community fragmentation.

Beneficial Impacts

Restoration actions within upland communities would be completed in several locations in the Valley under this alternative. The main restoration sites would be at the Group and Backpackers Campgrounds (2 acres), Yosemite Lodge (4 acres), Church Bowl Picnic Area (1 acre), Yellow Pine Campground (1 acre), the utility area at Ahwahnee (3 acres), and the talus slope zone at Curry Village (7 acres). The beneficial impacts to upland vegetation size and continuity in these sites are listed below:

• At the former Group and existing Backpackers Campgrounds, restoration would include small areas of upland mixed in with other high-value vegetation types. This impact would be minor.

• In the area between the Yosemite Lodge and the Merced River, areas of restoration would provide a continuous California black oak and upland vegetation corridor, linking the upland areas to restored riparian and meadow areas. This impact would be moderate.

• At Church Bowl Picnic Area restoration would have minor impacts on overall upland continuity.

• At Yellow Pine Campground, areas of formerly open ponderosa pine would be restored by prescribed fire to redevelop more naturally open characteristics. This area was known historically for its outstandingly large individual ponderosa pines. This impact would be moderate and long-term.

• In the Ahwahnee utility area, the current utility area would be removed and restored to upland, thus restoring habitat continuity. This impact would be minor.

• At the talus slope zone of Curry Village (7 acres), the continuity of upland stands of canyon live oak would be improved by the removal of housing and restoration of the talus slopes. This would be a moderate impact.

The beneficial impacts to natural structure, diversity and productivity of upland vegetation types would include the following:

• The canyon live oak community at Yosemite Village would be made more continuous through the removal of outbuildings in the vicinity of the NPS Operations Building (Fort Yosemite) with restoration of these areas to natural vegetation cover, with improved habitat and decreased fragmentation. This impact would be moderate.

• The ability to manage many of the continuous, unnaturally dense stands of incense-cedar and ponderosa pine with fire would be increased. This would help slow or stop the spread of annosus root rot through many of the currently developed areas of the east Valley (such as the Upper and Lower River Campgrounds Area) and would improve overall forest health. This impact would be major.

• The need to manage hazard trees within and around developed areas would be reduced due to the restoration of many current upland vegetation areas. Older individual trees and snags would be retained that provide important wildlife habitat. This impact would be minor.

• The productivity of smaller, more disjunct stands of upland coniferous vegetation would increase as a direct result of prescribed fire, reduction of stand densities, reduction in spread of annosus root rot (due to the reduction of stand densities), and establishment of understory herbaceous and shrub vegetation. This impact would be major.

• The understory integrity, diversity, and overall productivity would continue to improve as a result of re-establishment of native understory from the reduction of trampling in developed zones in the east Valley. This impact would be moderate.

• Upland vegetation encroachment into meadows and California black oak communities would be reversed through the use of fire management. The upland community would be reduced in size under Alternative 2 because of the removal of various developments in the east Valley, which would facilitate the ability of National Park Service staff to manage these areas with prescribed fire and other management tools. This would have a moderate effect on upland communities.

Adverse Impacts

The new development in upland communities would occur primarily within the east Valley and generally be concentrated in areas that have been previously disturbed. Most of the adverse impacts in the east Valley would result from the construction of new walk-in campgrounds east of Upper Pines, the new South Camp and Backpackers Campground, the addition to Upper Pines Campground, the campground checkpoint, the new walk-to campgrounds north of Tenaya Creek (2 acres), the new Curry Village housing/lodging (20 acres), the new lodging at Yosemite Lodge (5 acres), and the new parking at Camp 6 (8 acres). The adverse west Valley impacts would primarily occur at the new North American Wall Picnic area (2 acres), and if it was found necessary, a new traffic check station at El Capitan crossover (10 acres).

Adverse impacts to upland vegetation size and continuity would occur within the following areas:

• At Yosemite Lodge, the addition of lodging in the area north of the current Northside Drive and associated parking would cause adverse, minor impacts to upland coniferous forest and canyon live oak communities because of the addition of new buildings, paved trails, and the need to trench underground to provide utilities to these structures. This area has been previously disturbed.

• At the Upper and Lower River Campground Area, upland communities would also be converted from existing upland back to a mosaic of California black oak, riparian, and meadow communities through the removal of fill material. This would have only a minor impact on upland communities because this area does not have an intact understory and was not originally upland vegetation.

• The new walk-in campgrounds in the Valley would have a moderate impact on upland communities due to trampling of the understory layer.

• The addition of South Camp and the new Backpackers Campground would result in moderate upland impacts due to trampling and loss of understory vegetation.

• New lodging at Curry Village would be constructed outside of the talus slope zone near the existing lodging. This impact would be minor because the area is currently impacted by trampling.

• The potential development of a traffic check station at El Capitan crossover with pavement, utilities, and infrastructure (if required) would have a major impact on up to 10 acres of relatively undisturbed upland vegetation.

• Redevelopment of parking at Yosemite Village (Camp 6 area) for 550 vehicles would directly impact 8 acres of upland vegetation. Most of this area has already been extensively impacted by past and present uses for housing, material storage, and parking. Impacts would be minor as a result.

• Some turnouts along road corridors would be removed and restored; however, the increased width of Southside Drive and new pavement for multi-use trails would result in an overall increase in pavement throughout the Valley, creating a moderate, adverse impact to upland vegetation by decreasing the size of upland habitat and increasing fragmentation.

Adverse impacts on natural structure, diversity, and productivity of upland communities would include:

• Construction of multi-use paved trails adjacent to Southside Drive, from El Capitan crossover to Swinging Bridge and from Curry Village east to Happy Isles, would create additional paved areas with associated impacts to drainage, direct loss of vegetation, and an increased level of habitat fragmentation. These trails would have a minor impact to upland communities because of their proposed development adjacent to existing roadways and existing levels of disturbance along these corridors.

• A number of the restoration actions proposed would convert existing upland vegetation types to highly valued resource types (meadow, riparian, and California black oak). This would have a minor impact on the upland vegetation community because many areas to be converted were originally highly valued resource vegetation but have since been modified due to human influences.

California Black Oak Communities

The California black oak vegetation type is considered a highly valued resource because of its transitional character between wet meadows and drier uplands as well as its links to wildlife and ethnographic resources. Under Alternative 2, the actions proposed would result in approximately 9 acres of adverse impacts and approximately 19 acres of beneficial impacts to this community. The overall impact of this alternative on California black oak woodlands in Yosemite Valley would be major and beneficial due to the limited nature of this community in the Valley and the long-lived nature of these trees.

Beneficial Impacts

The restored California black oak areas would primarily occur in the former Upper and Lower River Campgrounds; Lower and North Pines, Backpackers and Group Campgrounds (15 acres); the Yosemite Lodge area (2 acres); and at the Ahwahnee tennis courts (1 acre). Restoration at the Church Bowl Picnic Area and the Superintendent’s House (Residence 1) would improve approximately 1 more acre of California black oak woodland.

Beneficial impacts on the size and continuity of California black oak vegetation are listed below:

• Removal of North Pines Campground and the concessioner stable would facilitate a continuous ecotonal transition from the riparian communities near Tenaya Creek and the Merced River to more California black oak stands to the south and east. Increasing the size of both California black oak and riparian communities, as well as eliminating most of the habitat fragmentation in this area (except for the small development of the amphitheater in a portion of the former concessioner stable area), would result in major long-term benefits.

• At Yosemite Lodge, adjacent areas of California black oak would be restored, thereby creating a larger, more continuous area of potential California black oak woodland. Due to the presence of large annosus root rot populations in the area, landscaping would focus on California black oaks (which are resistant to annosus root rot) rather than conifers, leading to a greater proportion of oaks in this area. Moderate, long-term beneficial impacts would result.

• Removal of the Ahwahnee tennis courts and associated non-native vegetation would remove the gap in this otherwise intact California black oak woodland that surrounds the courts, improving the continuity of the California black oak woodland through this entire area between the former Upper and Lower River Campgrounds and Ahwahnee Meadow to The Ahwahnee. This action would result in a moderate impact to the California black oak woodland community.

• Removal of fill material at restoration sites such as the Upper and Lower River Campgrounds Area would remove habitat for upland communities and restore original lower (topographic) layers to California black oak woodland, which would result in major long-term benefits.

• Restoration at the Superintendent’s House (Residence 1) and the Church Bowl Picnic Area would result in minor, beneficial impacts (primarily due to their small size).

The natural structure, diversity, and productivity of California black oak vegetation would benefit from Alternative 2 in the following ways:

• Stands in the east Valley would be minimally fragmented by development, roads, and encroaching conifers because of the enhanced ability to manage areas with fire, removal of facilities, and restoration of areas such as the Ahwahnee tennis courts and former Upper and Lower River Campgrounds into a mosaic of oak woodlands, meadows, and riparian areas. Moderate impacts would result.

• The natural structure of California black oak stands in the west Valley would improve due to prescribed burning, with the subsequent reduction in conifer encroachment resulting in a moderate impact. Other components of California black oak communities, such as deer grass (an important ethnographic resource), would significantly increase because of the reintroduction of natural and simulated natural processes such as fire and corrections in drainages, resulting in a moderate impact.

• Correction of drainage problems associated with roads (potentially on Northside Drive at El Capitan Meadow and Southside Drive in the Bridalveil Fall area) and removal of roads through Ahwahnee and Stoneman Meadows would improve the condition of California black oak stands in these locations by re-establishing natural drainages. This would correct problems associated with the impoundment of water upslope of roads, which keeps soils wetter for longer periods during the summer and therefore encourages armillaria rot to become fully established. These drainage corrections would result in major impacts to area vegetation communities.

• Restoration of historic landscaping characteristics at the Yosemite Valley Historic District housing area would improve the condition of existing mature California black oaks and facilitate the establishment of younger generations of these trees within the district, thereby improving stand structure and increasing the continuity of stands in this portion of the Valley. Moderate impacts are expected.

Adverse Impacts

The adverse impacts would primarily occur as a result of the new lodging at Curry Village (5 acres) and development of the new South Camp walk-in sites (2 acres), wilderness parking area (1 acre), and the Camp 6 parking area (1 acre).

The size and continuity of California black oak vegetation would be adversely impacted by:

• The development of additional lodging units adjacent to Stoneman House would result in a direct loss of some mature oak trees and regenerating saplings, as well as understory structure and function. In addition, radiating human activities and lack of fire would continue encroachment by conifers, leading to a gradual shift from a California black oak-dominated community to a mixed conifer—California black oak community that is more common in the Valley. The shift in dominant vegetation community composition impact would result in moderate, long-term impacts.

• The addition of the new South Camp walk-in sites would result in moderate California black oak impacts from trampling and loss of understory vegetation.

• Mature California black oak trees would potentially be removed during site grading and development, and additional trees could be lost with root impacts during construction, changes in drainage, and hazard tree removal, thereby resulting in loss of stand structure and continuity in all areas of proposed development and redevelopment of the east Valley. This impact would be moderate and long-term.

Meadow Communities

Approximately 8% of the Valley vegetation falls in the meadow vegetation type (NPS 1994e). Under Alternative 2 there would be 5 acres of adverse impacts at Camp 6 and 43 acres of meadow vegetation restored within the Valley. The overall impact of this alternative on the meadow vegetation type would be major and beneficial.

Beneficial Impacts

Alternative 2 would have a beneficial impact to 45 acres of meadow through the restoration of the area between the Yosemite Lodge and the Merced River (20 acres), Upper and Lower River Campgrounds (23 acres), and North Pines Campground (1 acres) and the removal of the Curry Orchard, followed by restoration (1 acres). Additional benefits to the meadows would be accomplished through improved water flow and a decrease in radiating impacts such as trampling.

The size and continuity, natural structure, diversity, and productivity of meadow vegetation would be beneficially affected by the following actions:

• The ecological restoration of the entire area south of the proposed new road alignment at Yosemite Lodge (aside from utilities and access near the confluence of the Merced River and Yosemite Creek) would have major beneficial effects on the ecological function of this section of the Valley, with increased meadow and riparian acreage, enhanced wetlands, and minimal fragmentation of a large low-lying area.

• The meadow size of Ahwahnee and Stoneman Meadows through the removal of the bisecting roads would increase substantially, with improved natural drainage patterns and continuous meadow cover over large areas of the east Valley, which would result in a major impact.

• Areas of former meadow at the Upper and Lower River Campgrounds; Ahwahnee Meadow where it is bisected by Northside Drive; and former campground sections of Lower Pines Campground, Southside Drive near Bridalveil Fall, and Cook’s Meadow would be restored by unburying meadow soils where fill was added. Hydrology would be restored over time through the restoration of original topographic variations and the re-establishment of native herbaceous species (due to improved soil and hydrologic conditions). This would result in a major impact.

• Connectedness of meadows to riparian and wetland areas would be created by the removal of roads and reconstruction of portions of roads to facilitate natural drainage patterns, which would result in a major impact.

• Implementing the River Protection Overlay, with access directed to appropriate sites along the river, would minimize impacts to this critical ecotone and result in a major impact.

• Modification of roads at the Bridalveil Falls, El Capitan, and Cook’s Meadow areas to allow drainage would allow for the re-establishment of functioning oxbow and cutoff channels through meadows, creating a critical link between meadow, riparian, and wetland systems. These actions would also increase native plant establishment (due to wetter conditions), native biodiversity, and overall productivity because of changes in species, food for wildlife, cover, etc., and result in a major impact.

• Development of a multi-use paved trail between Curry Village and Yosemite Village that would potentially allow for removal of the boardwalk through north Stoneman Meadow. Removal of the boardwalk would increase the continuity of the meadow and adjacent oak woodland, resulting in minor impacts.

Adverse Impacts

Alternative 2 would have adverse impacts on meadow vegetation type in the area of Camp 6 (5 acres), where meadow once occurred and now only fragments remain.

The adverse impacts to size, continuity, structure, diversity, and productivity of meadow communities include the following:

• Construction of new parking in the area of Camp 6 would result in a negligible impact to the remaining meadow fragments (the existing meadow is less than an acre in size and severely fragmented by roads, trails, and utility lines).

• Development of a multi-use paved trail between Curry Village and Yosemite Village through the Upper and Lower River Campgrounds area would not allow for complete elimination of fragmentation and impacts to existing and potential meadow and riparian zones. Alignment of the multi-use paved trail along the utility corridor through the Upper and Lower River Campgrounds area would minimize fragmentation somewhat by overlapping uses, resulting in a minor impact.

• Development of a vehicle check station, if required, at El Capitan crossover could result in undesired/unplanned parking along road shoulders at El Capitan Meadow, resulting in additional impacts from vehicles, trampling, the continued need to remove hazard trees, and introduction of non-native plant species into the meadow. However, these radiating impacts would be mitigated through restricting parking along the roadway and restricting human use of the meadow, resulting in a minor impact.

Riparian Communities

Actions under Alternative 2 would result in an adverse impact to an estimated 7 acres of riparian vegetation but would create beneficial impacts to more than 96 acres of riparian vegetation. The overall impact of this alternative on riparian vegetation would be major and beneficial.

Beneficial Impacts

Restoration actions would be concentrated in the Merced River floodplain areas near Yosemite Lodge (19 acres); Upper and Lower River, Lower Pines, North Pines, Group, and Backpackers Campgrounds and the dump station (61 acres); Housekeeping Camp (9 acres); Yellow Pine Campground (3 acres); Swinging Bridge Picnic Area (2 acres); and the ephemeral stream that crosses through the talus slope zone of Curry Village (2 acres).

The beneficial impacts to size and continuity of riparian vegetation would occur from the following:

• Removal of Sugar Pine and Stoneman Bridges would eliminate the hydrologic alternations that are causing a loss of riparian vegetation both upstream and downstream from these bridges. This would allow restoration of a continuous riparian band along a majority of the Merced River and Tenaya Creek through the east Valley that is currently almost entirely denuded. These actions would result in a major impact.

• Removal of North Pines Campground and the concessioner stable would facilitate a continuous ecotonal transition from the riparian communities near Tenaya Creek and the Merced River to drier California black oak stands to the south and east. This would increase the size of both communities as well as eliminate most of the habitat fragmentation in this area, except for the small development of the amphitheater in a part of the concessioner stable area. This would be a major impact.

• Restoration of the Upper and Lower River Campgrounds area, Upper Pines Campground dump station, a portion of Lower Pines Campground, a portion of Housekeeping Campground within the 150-foot River Protection Overlay, and Group and Backpackers Campgrounds would facilitate re-establishment of riparian corridors (oxbows, cutoff channels) through these sites as well as along the Merced and Tenaya Creek.
  This would result in a major impact.

• Restoration of the riparian corridor within the River Protection Overlay at Camp 6 would improve the continuity of riparian habitat along the Merced River corridor through the east Valley and provide connection between the wetland and meadow communities to the northeast and northwest of the proposed parking area. The improvements would result in a minor impact.

• Ecological restoration of the entire area south of the proposed new road alignment at Yosemite Lodge (aside from utilities and access near the confluence of the Merced River and Yosemite Creek) would have major, beneficial effects on the ecological function of this section of the Valley, with potential for increased meadow and riparian acreage, enhanced wetlands, and minimal fragmentation of a large low-lying area.

• Yosemite Lodge landscaping would be designed to accommodate seasonal and ephemeral drainages, and channels would be revegetated with riparian species appropriate to the site to provide continuous riparian threads through the developed area, which would result in a moderate impact.

• The removal of Swinging Bridge Picnic Area would improve habitat condition of the riparian communities in this area, promoting the establishment of understory and herbaceous layers that are currently nonexistent. This action would result in a minor impact.

• Removal of the rubble pile from the western channel of Yosemite Creek would allow the western channel to flow for a longer period, enabling riparian vegetation to become established in this currently barren channel. The action would result in a moderate impact.

• Rehabilitation of bridges over Yosemite Creek in the braided stream channel area would remove impacts associated with undersized bridges, that have resulted in scouring of the channel banks and loss of riparian vegetation. This would provide a moderate improvement and reduce impacts to riparian vegetation in this area, in conjunction with removal of the western channel rubble pile.

• Redesign of portions of Southside Drive in the Bridalveil Fall area would facilitate riparian flow under the road and enhance the continuity of the riparian community upslope and downslope of the existing road. This would be a moderate impact.

• Repair and construction of the road between the Cascades Diversion Dam and Pohono Bridge would eliminate roadside parking and resultant human impacts on riparian vegetation along this section of the Merced River corridor, resulting in a minor impact.

Adverse Impacts

Adverse impacts would primarily take place at the new walk-in campsites east of Upper Pines Campground (3 acres) and at the new lodging at Curry Village (4 acres). Additional impacts would occur as a result of radiating use from these new and redeveloped sites.

Adverse impacts to size and continuity, natural structure, diversity, and productivity of riparian communities are listed below:

• New walk-in camp sites at Upper Pines Campground would cause minor impacts to riparian vegetation due to trampling and the use of fill to create flat spaces for tent pads.

• At Curry Village, a small area of riparian vegetation would be impacted in order for existing lodging to be relocated outside of the talus slope zone. This new lodging development would be designed to minimize impacts, which would result in local impacts that are moderate but minor in relationship to the overall impacts to riparian vegetation.

• Converting the trail south of the Happy Isles Loop Road between Curry Village and Happy Isles to a multi-use paved trail would result in continued and increased negative impacts to the fen (an alkaline wetland fed from groundwater sources located near Happy Isles) and adjacent riparian vegetation. These impacts would be due to widening the current trail to accommodate heavier bicycle traffic, with a long-term loss of more fen habitat. The fen is unique in Yosemite National Park, and any impacts would be considered major because of the rarity of this type of vegetation community.

• Development of a 550-vehicle parking lot in Yosemite Village would have a minor impact on riparian vegetation, with radiating uses to the Merced River. This impact would be mitigated by directing visitors to resilient areas of the riverbank.

• Development of a picnic area with restrooms, barbecue grills, and picnic table pads in the vicinity of Camp 6 could result in a moderate, adverse impact because of trampling and increased radiating impacts. This would result in a loss of structure and integrity of riparian vegetation. Impacts would be mitigated by fencing, signage, and other measures to keep trampling confined to the picnic area, which would result in a minor overall impact.

• Paving or hardening the eastern channel trail at Yosemite Creek for accessibility would directly impact some riparian vegetation because this action would involve widening or relocating the current trail. However, the area of impact would be small, and this site has already had an almost complete loss of herbaceous cover due to undirected foot traffic adjacent to the current access trail to Lower Yosemite Fall Bridge. The resulting impact would be minor.

Other Communities

The Alternative 2 actions would result in adverse impacts to about 5 acres of other types of vegetation ground cover. Twenty-seven acres of bare ground, orchards, watered lawns, bare areas, and developed open areas would be restored to either upland or highly valued resource vegetation types. The beneficial impacts have been discussed in the upland, California black oak, meadow, and riparian discussions above, and include restoration of the Curry Orchard to a mix of meadow, riparian, and California black oak stands and restoration of the concessioner stables at North Pines Campground to riparian and California black oak woodlands. Adverse impacts would occur in areas where sparsely vegetated lands would be developed, such as the addition of parking at Camp 6 and new housing and lodging at Curry Village. Overall, there would be negligible beneficial impacts on these other vegetation types under Alternative 2.

OUT-OF-VALLEY AREAS

Alternative 2 proposes new parking facilities at three out-of-Valley areas: El Portal; Hazel Green Ranch (with Foresta as an alternative site in the Big Oak Flat road corridor); and Badger Pass. Stables would be relocated to Foresta and 14 additional housing units would be added. In addition, if negotiations do not work out with the private landowner at Hazel Green, Foresta would be the preferred parking area in the Big Oak Flat corridor. New housing would be developed in the Wawona area, and a new visitor center/orientation center would be developed at the Big Oak Flat Entrance, South Entrance, and El Portal Entrance areas. No impacts would occur at Henness Ridge or South Landing. No restoration actions are proposed in any of the out-of-Valley areas except for El Portal; therefore, there would be no beneficial impacts in these areas other than in El Portal.

El Portal

Vegetation types found in the El Portal area of impact include oak (a type of upland vegetation) and riparian; however, the plant composition of these types varies from those of the Valley. Meadow and California black oak types are not represented here. The overall impact of this alternative on El Portal vegetation would be moderate and adverse.

Upland Communities

• Existing oak stands would experience moderate, long-term impacts from the development of housing throughout El Portal. Direct loss of trees would occur with the development of housing within areas that are already somewhat impacted by low-density housing, as well as new housing sites at Hillside East and Hillside West. These developments would prevent retained trees from reproducing (due to pavement, yard activities, landscaping, trampling, and the presence of structures), resulting in a decrease in the size and continuity of these oak woodlands.

• Natural structure, diversity, and productivity of upland communities would be moderately impacted because of the increased likelihood of non-native plant species and lack of natural fire and fire frequencies.

• Prescribed burning and mechanical manipulation surrounding El Portal would continue to maintain semi-natural stands of oaks around developed areas. These actions would promote oak regeneration by reducing competing vegetation. Many areas currently managed this way would be developed into housing, parking, and infrastructure, leaving fewer acres of oaks to regenerate, provide habitat, and add to the diversity of this area, which would result in a minor impact.

• The development of a parking area could require the removal of large individual oaks adjacent to the Merced River at Middle Road. The development of housing upslope of this site would eliminate connectedness of the oak stands on the slopes above El Portal with riparian and flat terrain oak communities. The action would result in a minor impact.

Riparian Communities

• Removal and restoration of the old treatment plant at Rancheria Flat adjacent to the river would enhance the continuity of riparian vegetation along this curve of the Merced River, with potential increased habitat for rare plant species growing adjacent to the site. This action would result in a major impact to vegetation communities in the area.

• Implementation of the River Protection Overlay and management zoning, as prescribed in the Merced Wild and Scenic River Comprehensive Management Plan, would help protect the riparian corridor throughout the El Portal Administrative Site and result in a minor impact.

• Restoration of the sand pit area, with removal of remaining concrete wing walls and re-establishment of riparian vegetation, would enhance the river corridor and increase potential habitat for Congdon’s woolly-sunflower, a state-listed rare plant species. This would result in a minor impact.

• Riparian areas would receive minor impacts with the development of high-density housing at Hennessey’s Ranch (due to their currently impacted condition). Associated increases in human use would cause a decline in the continuity of this plant community as social trails develop.

• The size of riparian areas would continue to be impacted by existing development and new development (Hennessey’s Ranch, Village Center). A continued decline in riparian plant community size would also occur both in length along the river and width from the water’s edge up to the bank edge, resulting in a minor impact.

• Increased human population, with an associated increase in landscaping, numbers of vehicles, and foot traffic (and means for seed dispersion), would result in more non-native plant species problems throughout the riparian and oak woodland areas. An increase in non-native species would result in a moderate impact.

• The isolated nature of riparian areas in the El Portal core area (Crane Creek to Foresta Bridge), caused by structures, and Highway 140 riprap, would continue to inhibit natural exchange of other biological components (mammals, amphibians, and reptiles) as well as wind-dispersed seeds. This would result in lower overall productivity of these areas and a minor impact.

Foresta

The development being considered for Foresta under Alternative 2 includes stables, a Volunteers-in-the-Parks Campground, and the replacement of 14 employee houses destroyed in the 1990 A-Rock Fire, and, if Hazel Green failed as an option for parking, a day-visitor parking facility. The area of potential impact would be approximately 2 acres for the relocated stable facilities, 3 acres for the campground and, possibly, additional space for parking. Housing impacts would occur within existing developed areas. The overall impact of Alternative 2 on Foresta vegetation would be minor and adverse and would increase to moderate and adverse if parking were established at this site

Adverse Impacts

• Development of the National Park Service and concessioner stables at McCauley Ranch, including access road widening and rebuilding of a bridge along the access road, would further break up the continuity of the upland and riparian communities that exist along this road corridor. This impact would be minor because road is already there.

• The effect of the re-establishment of a campground at its former site (moved temporarily to Yellow Pine Campground in Yosemite Valley following the A-Rock Fire) would increase vehicle traffic to this site. This would increase the risk of introduction of non-native plant species. Non-natives impact the natural structure of communities, altering the natural diversity and generally leading to less productive habitats for native wildlife, which would result in a moderate impact to vegetation.

• Use of the Foresta area, and specifically Big Meadow, would likely increase substantially as a result of the development of a parking facility above the meadow. This would reduce the size and continuity of vegetation (by paving) and increase radiating use levels to the riparian and meadow communities in and around Foresta, resulting in a moderate impact.

• Isolated but extreme impacts from the establishment and spread of non-native plant species (including spotted knapweed, yellow star-thistle, oxe-eye daisy) would occur at a much more rapid rate due to substantially increased vehicle use of this area with development of a parking area. Management efforts would continue to attempt to contain and control (and eventually eradicate) existing and new non-native plant species. Development of a new parking area would result in a major impact.

Badger Pass

The vegetation in the area of potential development within the Badger Pass area includes white and red fir (upper montane forest). A 400-space parking area would be designated within the existing ski area parking lot. Up to an additional 1 to 2 acres of new development would be required for the associated utilities. The overall impact of this alternative on the Badger Pass area vegetation would be minor and adverse.

Adverse Impacts

• Parking for 400 vehicles would require the development of additional utilities to handle the increased demand for water and restroom facilities, thus leading to expanded disturbance of shrubs and herbaceous plants within the conifer forest. This impact would be minor because the new parking area would be delineated within the existing parking area. Therefore, the new impact would be limited to the associated utilities required for summer use, as well as potentially increased radiating impacts from higher levels of human use of the area during the summer.

Henness Ridge

Alternative 2 would include no actions in the Henness Ridge area.

Hazel Green

The vegetation at Hazel Green includes conifer forests, California black oak, meadows, and riparian areas. Up to 27 acres of vegetation would be impacted under Alternative 2 by development of a parking area and access road. Overall impacts to vegetation would be moderate and adverse with the implementation of mitigation measures described in Chapter 2.

Adverse Impacts

• The proposed access road would require the removal of a substantial number of large sugar pine and white fir trees. Due to the relative rarity of the sugar pine-dominated forest type in the Sierra Nevada (caused by past logging, white pine blister rust, catastrophic stand-replacing fires, or some combination of these factors), this action would result in a moderate and long-term impact on this forest.

• Development of a parking area at the headwaters of Hazel Green and Bull Creeks on Hazel Green Ranch would remove ponderosa pine/incense-cedar and ponderosa pine communities. Both are abundant in the area, and these impacts, although long term, would have minor impacts on the ecology of the forest types in the area.

• The red willow community would most likely be removed from the site during construction of the access road, which would cross the drainage ditches and the seeps at the Hazel Green headwaters. This would be a short-term, moderate impact. The construction of the road would, however, require development of additional ditches and culverts, creating potential habitat for red willow over time. This would result in long-term, minor impacts due to a net increase of paved ground.

• Radiating impacts to the open stands of ponderosa pine/California black oak and meadow areas would occur with the potentially substantial increase in human activity in the Hazel Green Ranch area, resulting in an increased potential for establishment of new non-native species in the meadow as well as loss of fire as a management tool in this area. These impacts would be long-term and minor.

Wawona

Construction of housing with associated infrastructure improvements would have an overall long-term, moderate, adverse impact on vegetation in Wawona.

Adverse Impacts

• The addition of housing on approximately 8 acres of land would adversely impact the lower-elevation, mixed conifer forest and stands of California black oak, resulting in a moderate impact. The size of the stands and continuity of the forest canopy would be broken by the addition of housing units and associated infrastructure.

• Continuity of the surrounding vegetation would be further impacted by the need to manage for hazard trees that could potentially impact this new housing development. The impacts would be minor.

• The overstory, understory, and herbaceous vegetation structure would be adversely impacted by the addition of housing, access roads, and trails, and the installation of infrastructure. Some vegetation structure could be maintained through site planning to avoid large trees and to concentrate housing to allow for larger blocks of intact vegetation between units. The impacts would be moderate.

• The diversity of native vegetation would decline due to the loss of some layers of the forest (primarily understory and herbaceous) from developments under the overstory canopy. The diversity decline would result in long-term, moderate impacts.

• The potential for introduction and establishment of non-native plant species would increase because of landscaping and groundskeeping activities in and around the housing area. This could be minimized by aggressive adherence to the landscaping guidelines outlined in the Vegetation Management Plan.

• Productivity of the site would decline because of the need to remove hazard trees, resulting in a loss of structure and diversity. These dying and dead trees and snags currently provide habitat for a wide range of wildlife, which would be impacted by the loss of these trees at this site. This impact would be long term, moderate, and adverse.

• Increased ground disturbance during construction and through higher levels of human use would increase the potential for non-native species to be established by inadvertent introductions. Because the site is currently not impacted by many non-natives, this would be a short- to long-term, moderate, adverse impact.

• Impacts radiating to surrounding areas (the river to the north and designated Wilderness to the south and east) would directly effect ground cover, thereby changing the structure of litter and duff (through trampling) and resulting in reduced effectiveness of prescribed fire activities. This would impact the National Park Service’s ability to continue managing natural stand structure (and thus productivity) throughout the site. However, this could be mitigated through fencing, trails, linking to established trail systems, and signs to keep people out of sensitive areas, resulting in a minor impact.

Big Oak Flat Entrance

Additional parking and construction of a new visitor contact station (visitor center) would increase the footprint of the existing site by up to 5 acres. Impacts at the Big Oak Flat Entrance would be long term, adverse, and minor due to the small size of additional impact, the existing level of habitat fragmentation, and the existing high potential for introduction of non-native plant species.

Impacts to upland vegetation (ponderosa pine forest and mixed conifer forest) may occur depending on the actual site design, which is not known at this time. Impacts would include paving, the removal of trees and groundcover, an increased difficulty in managing fuels and vegetation structure with fire (due to the presence of additional structures requiring fire protection), and trenching impacts to root systems (with potential weakening of the health of directly affected trees).

Tioga Pass Entrance

Tioga Pass vegetation is characterized by a mosaic of both wet and dry subalpine meadows (dominated by native perennial grasses, sedges, rushes and forbs), and lodgepole pine forests. Continued degradation of these vegetation types would occur under Alternative 2. The impacts resulting from this alternative would be long-term, moderate, and adverse because of a loss of vegetation and further degradation of vegetation community structure and diversity within a currently disturbed area.

Adverse Impacts

• Construction of a new visitor center and associated parking (with potential impacts of up to 5 acres in the vicinity of Tioga Pass) would impact lodgepole pine forests and wet and dry subalpine meadows. Dry meadows and lodgepole forests would be affected by paving and the addition of structures, utility lines, and trails, thereby reducing both the size and continuity of these vegetation types and resulting in long-term, moderate and adverse impacts. Wet meadows would receive moderate, adverse, and long-term impacts as a result of uses radiating from increased human activity in the area. Impacts to wet meadows could be mitigated by more clearly defining trails leading to the Mt. Dana cross-country route and would most likely remain moderate (despite any mitigation) simply as a result of increased levels of human use in the area.

• Paved areas and structures would result in changes in drainage patterns, with resulting moderate, adverse impacts. Increased numbers of visitors because of the new visitor center would increase the likelihood of additional firewood collection (causing a loss of nutrient recycling). More vehicles in the area would increase the chance of non-native plant establishment as a result of more trampling and denuded soils.

South Entrance

Vegetation at the South Entrance to Yosemite National Park is characterized by dense montane, mixed conifer forest dominated by a white fir overstory with subordinate sugar pine, Douglas-fir, ponderosa pine, and Jeffrey pine. Riparian vegetation occurs along ephemeral and perennial stream channels. Continued degradation of these vegetation types would occur under Alternative 2. The impact of this alternative would be long-term, minor, and adverse because there would be some increase in vegetation loss and degradation as compared to the existing condition.

Adverse Impacts

• Increased parking and structures would further add to the fragmentation of the area, with increased loss of riparian vegetation caused by potentially filling drainages and increased loss of forest cover. The loss of riparian vegetation could be minimized by using existing old road and railroad corridors rather than creating new developed areas, resulting in minor, adverse impacts due to the small area disturbed. Forests would be impacted by the loss of up to 5 acres of trees in a currently forested area. Additional impacts would occur from the expansion of the hazard tree management zone along the corridor and around new parking areas.

• An increase in paved areas, how long vehicles are parked, and levels of human use in the South Entrance area would increase the potential for introduction and establishment of non-native species through higher levels of road-edge maintenance, increased introduction of sand with potential weed seeds, and more people with seeds clinging to clothing and cars. Impacts would be moderate and adverse to riparian areas and minor for forested areas.

• The increased human population would make reintroduction of fire into this area more problematic due to smoke and the presence of structures. These limitations could be minimized by site design to concentrate structures in as small an area as possible. Vegetated "islands" would also be minimized to allow management of adjacent vegetation with fire.

CONCLUSION

Adverse impacts would occur to all vegetation types within Yosemite Valley under Alternative 2; however, the majority of the impacts would occur within upland and other (orchards, bare ground, lawns) vegetation types. Overall, there would be a major reduction in habitat fragmentation of the most highly valued vegetation types in Yosemite Valley under Alternative 2. Implementation of the River Protection Overlay would facilitate this improvement. Both meadow and riparian areas would receive major beneficial effects from the removal and/or consolidation of facilities out of the Merced River floodplain, including two historic bridges and former campsites. There would be an increased ability to restore large portions of the Valley to natural conditions with native understory and overstory composition and structure, increasing wildlife habitat. Camp 6 would still be used for parking, with continued impacts to adjacent riparian and meadow areas. California black oak woodlands would also receive major, beneficial effects by the removal of some structures within existing oak stands and the potential for restoration of large areas of former California black oak. Upland communities would receive minor, beneficial impacts from the removal of some facilities and the resulting improved conditions of the remaining stand structure and productivity.

In El Portal, moderate, adverse impacts would occur to the oak, upland, and riparian vegetation communities due to new development and radiating impacts from an increased human population.

Vegetation in the Wawona, Hazel Green, Foresta, and Tioga Pass areas would be moderately, adversely affected; upland forests and California black oaks would be affected by new housing and increased opportunity for non-native plant establishment; montane forests would be affected by a new parking/transit facility; meadow and riparian areas would be affected by increased opportunities for non-native plant establishment; and lodgepole forest would be affected by a visitor center. Expected radiating impacts would have minor, adverse effects to meadow, riparian, and other adjacent vegetation types because of an increased human presence in the spring and summer. If parking were added at Foresta rather than Hazel Green, additional impacts there would be moderate.

Long-term, minor and adverse effects would occur at Foresta (without parking), the Big Oak Flat entrance area, the South Entrance area, and Badger Pass because of increased radiating impacts from a greater human presence, a higher chance of non-native plant establishment, and an increased fragmentation of vegetation.

The overall impacts of Alternative 2 on vegetation would be long-term, moderate, and beneficial based on (1) the large areas of highly valued resource vegetation that would be restored, (2) the majority of the adverse impacts would occur to non-highly valued resource vegetation types (uplands and other), and (3) the limited amount of new fragmentation generated.

CUMULATIVE IMPACTS

The overall impacts of past, present, and reasonably foreseeable future projects on vegetation would be the same for Alternative 2 as is described for Alternative 1. The majority of adverse impacts to upland vegetation in Yosemite Valley under Alternative 2 would occur within non-highly valued resource vegetation types. Construction of the Indian Cultural Center would result in the loss of California black oak and upland vegetation communities, which would offset a portion of the benefits associated with Alternative 2. There would also be short-term, adverse impacts to upland communities in Yosemite Valley due to the conversion of current conifer communities to more highly valued plant communities such as riparian, meadows, and California black oak woodlands. Alternative 2, in conjunction with those areawide project impacts described in the cumulative discussion of Alternative 1, would result in long-term, moderate, and adverse impacts to upland vegetation in El Portal, Wawona, Hazel Green, and Badger Pass, as well as at all park entrance stations due to the addition of structures and parking. Areawide projects that would contribute to cumulative beneficial impacts to vegetation include the Hazel Green Ranch development, in which meadow preservation would be emphasized as part of the project; Yosemite Gateway Plaza, Big Oak Flat (Tuolumne Co.) improvements; and the A-Rock Reforestation (USFS, Stanislaus) project. Although this alternative would result in loss of individual upland trees, it would constitute an improvement in the overall function of remaining upland communities through the re-introduction of fire, with a resultant improved stand density and health. The overall effect of the future projects on upland vegetation would be minor and adverse because regional vegetation management would offset some of the adverse development impacts (vegetation loss and degradation) resulting from areawide projects.

Increased human activity and related air quality degradation in the Yosemite Valley and other montane areas could adversely affect ponderosa pine, Jeffrey pine, and other ozone-intolerant species. The National Park Service has operated an ozone monitoring station at Turtleback Dome for more than a decade to identify ozone trends in Yosemite Valley. Although cleaner burning vehicles and fuels should reduce the amount of ozone in the atmosphere in the future cumulative effects to such plant species are expected to continue.

Other cumulative impacts to vegetation under Alternative 2 would include community fragmentation because of increased land development and potential continued introduction of non-native plant species. Cumulative impacts to riparian vegetation would also be expected due to development and other pressures along the narrow Valley floor adjacent to the Merced River.

Restoration actions proposed in Yosemite Valley and the removal of structures with resulting decreased habitat fragmentation in some areas, would result in more acres of California black oak woodland. Potentially there would also be more acres of potential California black oak woodland through the re-introduction of fire into stands adjacent to uplands. Loss of California black oaks, valley, canyon live, and blue oaks through construction in Wawona and El Portal, however, would increase habitat fragmentation of these sites; site planning to avoid large trees and designing landscapes to minimize irrigation impacts would help mitigate these actions. Most talus (canyon live oak) communities in Yosemite Valley would either not be impacted or would be restored under this alternative. In conjunction with reasonably foreseeable future projects, Alternative 2 would have cumulative negligible to minor, beneficial impacts to oaks.

Alternative 2 calls for the implementation of a River Protection Overlay in Yosemite Valley, which would create long linear sections of intact riparian vegetation after restoration efforts were completed. The natural links with meadows would be restored, and large, continuous meadow areas would be recreated in the east Valley. However, this alternative also prescribes additional multi-use paved trails, which often follow or cross riparian areas. Impacts could also occur to subalpine meadows at Tioga Pass. Thorough site planning could prevent impacts to riparian and meadow zones in all new development areas by avoidance, resulting in a cumulative moderate beneficial impact to riparian and meadow vegetation.

Therefore, the overall cumulative impact of Alternative 2 on vegetation, in conjunction with reasonably foreseeable impacts from future projects, and plans inside and outside of Yosemite National Park would be minor beneficial.

| Table of Contents | Environmental Consequences | Alternative 1 | Alternative 2 |
| Part 1 | Part 2 | Part 3 | Part 4 | Part 5 | Part 6 |

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