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Wetland Statement of Findings for the Curry Village and East Yosemite Valley Campground Improvements Project
PURPOSE OF THIS STATEMENT AND FINDINGS The purpose of this Wetland Statement of Findings is to review the Curry Village and East Yosemite Valley Campgrounds Improvements Project in sufficient detail to: • Avoid, to the extent possible, the short-and long-term adverse impacts associated with the destruction or modification of wetlands and to avoid direct or indirect support of new construction in wetlands wherever there is a practicable alternative • Describe the effects on wetland values associated with the proposed action • Provide a thorough description and evaluation of mitigation measures developed to achieve compliance with Executive Order 11990 (Protection of Wetlands) and National Park Service Procedural Manual 77 - 1 : Wetland Protection • Ensure “no net loss” of wetland functions or values Wetlands and deepwater habitats within the project area include the riverine habitat of the Merced River and numerous areas of palustrine forest, palustrine scrub shrub, and palustrine emergent within the Merced River corridor. Wetland and aquatic habitats that may be affected are predominately associated with the Merced River corridor and several creeks that cross through the area. Wetlands in the project area were mapped by Jones and Stokes in 2002 and 2003 under contract to the National Park Service. Wetlands located in the project area and the nearby North Pines area are shown in figures E- 1 through E- 3 . Based on the information as mapped by Jones & Stokes ( 2003 a and 2003 b), identified wetlands within the Curry Village and East Valley Campgrounds study area include 4 . 612 acres palustrine emergent wetlands, 0 . 259 acre palustrine scrub-shrub wetlands, 1 . 315 acres palustrine forested wetlands, 0 . 184 acre riverine intermittent streambed, and 3 . 808 acres riverine lower perennial unconsolidated bottom. Based on a review of the project design documents and facility layouts, the wetland areas that are expected to be filled in connection with the proposed project include one 30 feet long section of a 2 -feet wide drainage channel near one of the first five cabin-with-bath structures (feature CV- 15 on figure E- 3 ), one 75 feet long segment of a 3 -foot wide drainage channel at the Alternative 3 site of the proposed mountain shop (feature CV- 17 b on figure E- 3 ), and a total of 380 feet of 1 -foot wide drainage channels at the site of a new campground check station and RV dump station (features UP- 13 , UP 14 , and a portion of UP- 12 on figure E- 2 ). These areas are all mapped as riverine intermittent streambed. Two of these areas (CV- 15 and CV- 17 b) are identified by Jones & Stokes ( 2003 b) as isolated intrastate waters not subject to Army Corps of Engineers jurisdiction. In addition, feature CV- 15 appears to be an artificial channel that is exempt from NPS compensation requirements, and this is the only wetland feature affected by the first phase of construction activity. The total area to be affected would be approximately 0 . 015 acre. Project design features have been incorporated to avoid fill in other identified wetland areas. Specific wetland classes identified within the project area are limited to riverine (rivers, creeks, and streams) and palustrine (shallow ponds, marshes, swamps, and sloughs). Using the Cowardin classification, specific wetland and deepwater classes within the project area include: • Riverine Intermittent Streambed. This wetland type consists of the smaller watercourses that flow in the winter, spring, and summer during periods of runoff and snow melt. The channels are typically bare, but the edges often support palustrine emergent vegetation. A total of 0 . 953 acre of this habitat was identified in the project area (Jones & Stokes 2003 a and 2003 b), and approximately 0 . 015 acre would be filled in connection with the proposed project development. Nearly half of the areas to be filled are isolated from other wetlands, and do not contribute to the function or values of the natural wetlands in the general area. • Riverine Lower Perennial Unconsolidated Bottom. This wetland type is characterized by a low gradient and low water velocity, and by a substrate that consists mainly of gravel, sand, silt, and some clay. In addition, these wetlands have less than 30 percent vegetative cover and a water regime that is permanently, or semi-permanently flooded and intermittently exposed (Cowardin et al. 1979 ). A total of 3 . 808 acres of this habitat was identified in the project area (Jones & Stokes 2003 a and 2003 b), none of which would be filled in connection with the proposed project development. • Palustrine Emergent Wetland. This wetland type includes meadows, marshes, and vegetated ponds. Emergent wetlands are characterized by erect, rooted, herbaceous hydrophytes with an aerial coverage of at least 30 percent (Cowardin et al. 1979 ) that are usually present for most of the growing season. A total of 4 . 612 acres of this vegetation type was identified in the project area, though none is expected to be filled in connection with the installation of the proposed facilities. • Palustrine Forested Wetland. These riparian forest habitats are regularly inundated by normal high-water flows or flood flows. The uppermost layer of vegetation consists of trees at least 20 feet tall with an aerial coverage of at least 30 percent (Cowardin et al. 1979 ). A total of 1 . 315 acres of this vegetation type was identified in the project area, though none is expected to be filled in connection with the installation of the proposed facilities. Figure E-1 Delineation of Waters of the United States, Including Wetlands, Campground Exansion Area
Figure E-2 Delineation of Waters of the United States, Including Wetlands, Campground Expansion Area
Figure E-3 Delineation of Waters of the United States, Including Wetlands,Curry Village Area
• Palustrine Scrub-Shrub Wetland. This wetland type includes an uppermost layer of vegetation dominated by woody vegetation less than 20 feet tall, such as small willows and shrubs with an aerial coverage of at least 30 percent (Cowardin et al. 1979 ). A total of 0 . 259 acre of this vegetation type was identified in the project area, though none is expected to be filled in connection with the installation of the proposed facilities. The size, connectivity, and integrity of wetlands in the project area, particularly palustrine forest, palustrine scrub shrub, and riverine habitat, have been directly compromised by development and visitor activities. Existing Structures in Wetlands Yosemite Valley visitor facilities and campgrounds are currently dispersed throughout the Valley, including utility infrastructure within wetland areas. Wetlands exist in the Curry Village , South Camp, and Upper and Lower Pines campgrounds project planning areas. Existing structures and wetland areas in the project planning areas are shown on Figures E- 1 through E- 3 . ENVIRONMENTAL CONSEQUENCES OF THE PROPOSED ACTION ON WETLANDS There would be minor to moderate impacts to wetland and aquatic habitats related to implementation of the proposed action. The removal of campsites from the River Protection Overlay at Lower Pines Campground would enhance the Merced River corridor and have a beneficial impact on wetlands. Construction impacts to wetland and aquatic habitats would be related to temporary disturbances associated with the movement of construction heavy equipment and could include soil disturbance and compaction, dust, vegetation removal, root damage, erosion, and introduction and spread of non-native species. Mitigation measures have been incorporated into the proposed action to reduce these potential impacts. The addition of silt, the resuspension of sediment, or the introduction of pollutants (e.g., fuels, lubricants) related to construction activities could degrade the quality of native wetland and aquatic habitats in the immediate vicinity of construction activities. Mitigation measures have been incorporated into the proposed action to prevent these potential impacts. The wetlands at Curry Village consist of palustrine forest, palustrine emergent, palustrine scrub shrub, and riverine intermittent streambed. The Yosemite Valley Plan anticipated that new development and redevelopment in wetlands would occur at Curry Village (near maple-dominated drainages), and that wetland avoidance would be maximized. The five cabins-with-baths located south of the parking area and the relocated Mountain Shop would affect identified wetlands in Curry Village . Five cabins-with-bath structures are proposed as part of the first phase of the Curry Village and East Valley campgrounds project (Alternatives 2 and 3 ). One of these five cabins-with-bath structures is located immediately adjacent to the channel labeled CV- 15 on figure E- 3 . This cabin location was selected to minimize tree removal and will require the realignment of a 30 -foot section of the 2 -foot wide drainage channel. The drainage in question appears to be an artificial channel designed to handle sheet flow in this area, and no developed wetland vegetation is present in the area to be realigned. In addition, this channel is not connected to other wetlands, and the proposed realignment is not expected to adversely affect the function or values of natural wetlands in the general area. The total area affected is less than 0 . 002 acre. Because of the isolated nature of this wetland, its artificial nature, and its small size, this realignment is not believed to be subject to Army Corps of Engineers jurisdiction, and it is believed to be exempt from National Park Service compensation requirements in accordance with Procedural Manual 77 . 1 : Wetlands Protection. The relocation of the Mountain Shop is proposed as part of a later phase of Alternative 3 (the Preferred Alternative) of the Curry Village and East Valley campgrounds project. The proposed new Mountain Shop site would affect an identified drainage feature CV- 17 b on figure E- 3 ). This wetland feature appears to be an isolated drainage that is disconnected from other wetlands in the general area. The wetland affected by the Mountain Shop is designated as riverine intermittent streambed, and the area affected may be an artificial channel. Because this feature is isolated from other waters, it is not expected to be subject to Army Corps of Engineers jurisdiction. In addition, it is considered exempt from National Park Service compensation requirements because it is an artificial channel that does not contribute to the function or value of other wetland areas, and the area affected will be less than 0 . 005 acre. Potential disturbance would also be associated with the installation of the new parking area for cabins-with-baths at Curry Village that is proposed as part of the first phase of project development (Alternatives 2 and 3 ). This parking area crosses a two-foot wide intermittent stream, which is expected to require installation of a 30 -feet long culvert to direct flows under the parking lot. This culvert will be designed as a bottomless culvert with at least a 30 -inch diameter to preserve the streambed conditions. By adhering to this design standard, this culvert installation does not constitute fill of this wetland. Flows would not be impeded from connecting to the Merced River . Indirect impacts associated with visitor access to other areas of the wetland are likely to be minor, since the area of effect is small. This would result in a local, long-term, minor, adverse impact to wetlands. Construction impacts could include temporary diversion of flows during installation of the culvert and paving of the lot. Construction activities associated utility and roadway maintenance also could affect wetlands in Curry Village . Siltation of wetlands during grading activities in areas adjacent to the stream corridor could also occur. The application of mitigation measures described in Chapter II of the Curry Village and East Valley Campgrounds Improvements Project Environmental Assessment, specifically those related to the protection of wetland areas, minimization of disturbance areas, and prevention of spills, would reduce the potential adverse impacts to wetlands. Therefore, if these impacts occur, they are anticipated to be local, short term, minor, and adverse. Campground Check Station and Recreational Vehicle Dump Station New campgrounds check-in station and recreational vehicle dump station is proposed as a later phase of the Curry Village and East Valley campgrounds project (Alternatives 2 and 3 ). The alignment of the new access road to the campground check station and recreational vehicle dump station would cross a wetland in three locations and would be within this wetland for the turnaround in front of the building (features UP- 13 , UP- 14 , and a portion of UP- 12 ). The proposed buildings would not be located within the wetland designated as riverine intermittent streambed, but it is likely that this drainage would be modified in connection with facility construction. The total wetland area expected to be modified by the installation of this facility would be less than 0 . 009 acre. This modification will be subject to mitigation measures specified in the Environmental Assessment to prevent adverse effects on downstream wetland habitat and function, and this disturbance will be subject to National Park Service wetlands compensation requirements. Potential construction impacts include temporary diversion of stream flow and siltation of wetlands during grading and other earth moving activities. The application of mitigation measures, specifically those related to the protection of wetland areas, minimization of disturbance areas, and prevention of spills, would reduce the potential adverse impacts to wetlands. If these impacts occur, they are anticipated to be local, short term, minor, and adverse. Development of the South Camp campsites is planned to occur in a later phase of the Curry Village and East Valley Campgrounds Improvement project. The wetlands at South Camp consist of palustrine emergent and riverine intermittent streambed. These wetlands would be avoided by tightly clustering the parking area adjacent to the informal parking area. Additionally, the number of walk-in campsites associated with the preferred alternative represents a slight reduction in numbers (offset by an increase in the number of walk in campsites at Upper Pines) to accommodate campsite layout to avoid placement in high value emergent wetlands. No wetland fill is expected to be required in connection with the South Camp facilities. Development of the Upper Pines campground improvements is planned as part of the first phase of the Curry Village and East Valley Campgrounds Improvement project. The wetlands at Upper Pines Campground consist of palustrine forest, palustrine emergent, palustrine scrub shrub, and riverine intermittent streambed. Some of these wetlands drain to the Merced River through Lower Pines Campground, while others drain directly to the Merced River . Some of the riverine intermittent streambed wetlands drain the restored fen near Happy Isles. Several wetlands are located in development areas identified in the Yosemite Valley Plan . The proposed campground design has incorporated design features to prevent permanent fill of wetlands in this area. The proposed walk-in campsites and parking area would be located adjacent to a large braided area of intermittent stream. The service road and pedestrian path would cross this wetland (feature UP- 08 a on figure E- 2 ) in two locations, requiring installation of two small bridges that would span the wetlands and prevent alteration of wetland hydrology and vegetation. Bridge abutments or anchors will be placed outside the mapped wetland habitat, and no bridge supports are required in the wetland area. An RV loop will be added at the north end of the Upper Pines campground, and restroom facility improvements are planned throughout the existing drive-in campground area. The only identified facilities in wetland areas associated with the Upper Pines drive-in campsite area are two crossings of the roadside drainage channel adjacent to the Happy Isles Road (mapped as feature UP- 22 a on figure E- 2 ). These crossings are associated with a service road access to the planned RV loop restroom and a pedestrian path from the proposed RV loop to a crossing of the Happy Isles Road. These crossings will be designed using bridge structures or bottomless culverts that completely span the mapped wetland area to prevent fill within the wetland area. Potential construction impacts include sedimentation of wetlands and waters during grading, excavation, and other earthmoving activities. Additional temporary impacts could include intrusion of construction personnel and equipment into wetlands surrounding the project footprint. Construction would include measures to allow for maximum protection of the wetland area, therefore, if these impacts occur, they are anticipated to be local, short term, minor, and adverse. Construction activities would also include maintenance and repair to existing utility infrastructure in Upper Pines Campground, which are within existing utility corridors. These construction activities would include grading and trenching, resulting in a short-term, negligible impact to wetland resources. Construction impacts will be mitigated by minimizing the area disturbed and preventing runoff from entering wetlands during construction. Due to the proximity of proposed development, human visitation to the wetlands would likely increase, which would result in some trampling of vegetation and erosion of streambanks, potentially increasing sedimentation into a large area of wetland habitat. However, given that there will be no direct fill of these wetlands, the impacts would be local, long term, moderate, and adverse. Development of the Lower Pines campground modifications and related wetlands restoration are planned to occur in connection with a later phase of the Curry Village and East Valley Campgrounds Improvement project. The wetlands at Lower Pines Campground include palustrine scrub shrub and riverine intermittent streambed. These wetlands flow to the Merced River . Existing campsites and access roads would be removed from the River Protection Overlay. The redevelopment of Lower Pines Campground would avoid all wetland areas and enhance the Merced River corridor through the removal of built features adjacent to the river, potentially expanding the wetlands adjacent to the campsites being removed. Removal of existing campsites from wetland habitat would have a local, long-term, moderate, beneficial impact to wetlands. Potential construction impacts include sedimentation of wetlands and waters during removal of existing campsites in the River Protection Overlay. Additional impacts could include intrusion of construction personnel and equipment into wetlands surrounding the project footprint. The application of mitigation measures as described for Curry Village would reduce the potential adverse impact to a minor intensity. Cumulative effects to wetland and aquatic resources are based on analysis of past, present, and reasonably foreseeable future actions in Yosemite Valley in combination with potential effects of this alternative. The projects identified below include those projects that have the potential to affect local wetland patterns. Wetland and riparian systems of the Merced River corridor have been substantially altered by development and visitor activities. These changes have negatively influenced the size, form, and function of wetlands and the plants, wildlife, and aquatic species that inhabit them. Cumulative effects would be mixed, combining both adverse and beneficial effects. Cumulative beneficial effects on wetlands include wetland restoration, rehabilitation projects, and ecosystem management. Cumulative adverse effects would be related to increased facilities, regional growth, and visitor demand. Reasonably foreseeable future actions within Yosemite Valley are considered to have an overall beneficial effect on wetlands. For example, the Merced Wild and Scenic River Comprehensive Management Plan protects river-related natural resources through the application of management elements, including the River Protection Overlay, management zoning, protection and enhancement of Outstandingly Remarkable Values, and implementation of a Visitor Experience Resource Protection framework. Full implementation of the Yosemite Valley Plan would result in a net gain of 118 acres of wetlands in Yosemite Valley through actions such as restoration of Upper River and a portion of Lower Pines Campgrounds to natural conditions; removal of roads through Stoneman and Ahwahnee Meadows; and removal of other bridges (e.g., Sugar Pine and possibly Stoneman) affecting the natural flow of the Merced River. Alternative 1 could minimize these benefits since utilities would remain in the restoration areas and utility repairs needed in the future could continue to have short term, localized, adverse impacts to these resources. Farther downstream, removal of the Cascades Diversion Dam would also remove an unnatural constriction to the free flow of the Merced River , thereby enhancing natural river dynamics including wetlands and aquatic systems below Yosemite Valley . Some Yosemite Valley Plan projects, such as construction of a replacement footbridge at the Happy Isles area, construction of a vehicle bridge across Yosemite Creek near Yosemite Lodge, and expansion of some campgrounds in Yosemite Valley , have the potential to adversely affect local wetlands. These projects would be designed to ensure the long-term protection of wetlands consistent with the Merced River Plan, the Clean Water Act, and Executive Order 11990 : Protection of Wetlands. Cumulative actions would have a long-term, moderate, beneficial cumulative effect on wetlands within Yosemite Valley due to wetland restoration efforts. Past, present, and reasonably foreseeable future projects in combination with the proposed action would have a net long-term, major, beneficial effect on wetlands in Yosemite Valley due to wetland restoration efforts. The Proposed Action would result in fill of approximately 0 . 015 acre of identified wetland areas, and local, short-term, minor, adverse construction impacts to wetlands. Removal of campsites in Lower Pines Campground and subsequent restoration of this area would more than offset the identified wetland loss associated with the proposed action. Therefore, the localized long-term impacts to individual wetlands would be local, moderate, and adverse, and the proposed action would represent a net beneficial effect on wetland habitat and function. Alternatives considered in the Curry Village and East Yosemite Valley Campgrounds Improvements Project Environmental Assessment (Chapter II, Alternatives) include the No Action Alternative, Alternative 2 , and Alternative 3 . The No Action Alternative would maintain the status quo in the project area. Under the No Action Alternative, the River Protection Overlay and zoning prescribed in the Merced River Plan (NPS 2001 a) would be adopted; however, no removal of human-made structures and obstructions would be initiated. Historically significant sites, structures, and landscape features would be retained in their existing conditions and configurations. Archeological resources would continue to be managed as they are today. Curry Village and the campgrounds would remain in their existing condition without upgrade or expansion. Campsites and lodging units would remain at current levels (i.e., the number remaining after the 1997 flood and subsequent recovery efforts). Restoration of approximately one acre of currently disturbed wetlands in Lower Pines campground would not occur under this alternative. In conjunction with the No Action Alternative, the existing management and operation of the utility systems within the project area would continue, and previously planned routine repairs and maintenance would be implemented. Alternative 2 would implement the changes to the project area as envisioned by the Yosemite Valley Plan . Parking for overnight guests would increase and day-visitor parking would be eliminated in accordance with the Yosemite Valley Plan . The number of tent cabins would decrease, the number of cabins-with-bath and campsites would increase, and campsites located in the River Protection Overlay would be removed in accordance with the Yosemite Valley Plan . A new campground would be developed at the eastern edge of Curry Village and a new campground check station and recreational vehicle dump station would be constructed in accordance with the Yosemite Valley Plan. Electrical and phone services would be updated. Total fill of identified wetland areas associated with this alternative would be . 010 acre, including 0 . 002 acre of an artificial channel mapped as isolated waters. Restoration of approximately 1 acre of currently disturbed wetlands in Lower Pines campground would be enabled by this alternative. In conjunction with Alternative 2 , the existing management and operation of the utility systems within the project area would continue, and previously planned routine repairs and maintenance would be implemented. Alternative 3 would also implement the changes to the project area envisioned in the Yosemite Valley Plan . Parking would increase and day-visitor parking would be eliminated in accordance with the Yosemite Valley Plan . The number of tent cabins would decrease, the number of cabins-with-bath and campsites would increase, and campsites located in the River Protection Overlay would be removed in accordance with the Yosemite Valley Plan . A new registration building and Mountain Shop would be constructed in Curry Village . A new campground would be developed at the eastern edge of Curry Village and a new campground registration facility, recreational vehicle dump station, and central shower/restroom facility would be constructed in accordance with the Yosemite Valley Plan . Total fill of identified wetland areas associated with this alternative would be 0 . 015 acre, including 0 . 007 acre of isolated waters of which 0 . 002 acre is an artificial channel. Restoration of approximately one acre of currently disturbed wetlands in Lower Pines campground would be enabled by this alternative. In conjunction with Alternative 3 , the existing management and operation of the utility systems within the project area would continue, and previously planned routine repairs and maintenance would be implemented. Design or Modifications to Minimize Harm To Wetlands Construction Mitigation Measures and Resource-Specific Mitigation Measures To ensure that implementation of the proposed action protects natural, cultural, and social resources, a consistent set of mitigation measures would be applied during project implementation to avoid, minimize, and mitigate adverse impacts. Sustainable Design and Aesthetics The project will avoid or minimize impacts to natural, cultural, and social resources. The project will be designed to work in harmony with the surroundings, particularly the cultural landscape of the Yosemite Valley . The project will reduce, minimize, or eliminate air and water nonpoint-source pollution. The project will be sustainable whenever practicable, by recycling and reusing materials, by minimizing materials, and by minimizing energy consumption during project construction. The project will utilize building materials that represent natural tones and blend in with the surrounding wooded environment. Construction Mitigation Measures The National Park Service (and its contractors) shall implement the following Best Management Practices, as appropriate, prior to, during, and/or after construction activities. Specific tasks would include, but are not limited to, the following: • Preconstruction briefings will be required to educate construction crews on the measures required to protect natural and cultural resources. • Construction area boundaries, including staging areas, will be clearly marked to ensure that construction activities do not affect resources outside of the construction areas. All construction activity and storage of construction materials will occur within these marked areas. Construction and staging areas will be confined to the smallest area necessary. • Natural resources will be protected through biological monitoring, erosion and sediment control, use of fencing or other means to protect sensitive resources adjacent to construction, removal of all food-related items or rubbish to bear-proof containers, topsoil salvage, and revegetation. Fencing will be used to mark the limits of allowed construction disturbance and to mark specific high-value vegetation to be salvaged or preserved. Food shall be stored in accordance with park regulations. • Compliance monitoring will be implemented to ensure the project remains within the parameters of the National Environmental Policy Act and National Historic Preservation Act compliance documents, U.S. Army Corps of Engineers Section 404 permits, and other permits and regulations. Compliance monitoring will ensure adherence to mitigation measures and will include reporting protocols. • Water quality will be protected through the use of silt fences, sedimentation basins, and other control measures to reduce erosion, surface scouring, and discharge to water bodies. Excavated material will be stored in upland areas and stabilized to prevent discharge into water bodies or wetlands. • Wetland areas will be delineated and marked. Adjacent or nearby wetland areas not in the construction area will be fenced to reduce potential impacts from construction activities. • A noxious weed abatement program will be implemented. Construction equipment will be steam-cleaned and inspected to ensure that it arrives on site free of mud and seed-bearing material; seeds and straw material shall be certified as weed-free; and areas of noxious weeds will be identified and treated prior to construction. Areas treated to remove noxious weeds will be revegetated with appropriate native species. • A dust abatement program will be implemented during construction. Clearing of vegetation will be minimized to the greatest extent possible. Water or other compounds will be used to stabilize disturbed soils during construction; trucks hauling soil will be required to cover the soils during transport; and disturbed areas will be revegetated with native species after construction. Excavated soils will be stockpiled and covered. • A spill prevention and pollution control program for hazardous materials will be implemented. The program will emphasize proper hazardous materials storage and handling procedures; will outline spill containment, cleanup, and reporting procedures; and will limit refueling and other hazardous activities to designated upland areas. Signs prohibiting refueling will be posted in sensitive areas. Equipment will be inspected prior to use each day to ensure that hydraulic hoses are tight and in good condition. • A revegetation plan will be developed to ensure that salvage vegetation is used where possible and that native species are used. Monitoring will occur during the revegetation period to ensure the success of the revegetation plan. • All tools, equipment, barricades, signs, surplus materials, and rubbish will be removed from the project area upon project completion and revegetation of disturbed areas. The National Park Service project manager will make inspections to ensure that impacts remain within the parameters of the project and do not escalate beyond the scope of the environmental assessment, as well as to ensure that the project conforms to the U.S. Army Corps of Engineers Section 404 permits. The National Park Service project manager will assure that mitigation measures are followed. • Disturbed or developed areas will be used for staging whenever possible. Staging areas for individual projects will be identified during final design and will require approval by the National Park Service project manager. • Damage to natural surroundings in and around the work limits will be avoided. Temporary barriers to protect existing trees, plants, and root zone will be provided, if necessary. Trees and other vegetation will not be removed, injured, or destroyed without prior written approval. Ropes, cables, or fencing will not be fastened to trees. All existing resource protection fencing (post and rope) will be left in place and protected from heavy equipment. Resource-Specific Mitigation Measures • Perform site-specific geologic and geotechnical investigations of proposed buildings, facilities, and infrastructure requiring foundation design criteria to assess local liquefaction and cyclic densification potential, surficial expansive soil, and strength of soil. Perform investigations during final design phase. • Incorporate appropriate engineering design for areas comprised of liquefiable soils, weak or expansive soils, or soils above the base of frost zone. • Incorporate appropriate landscape design for areas with the potential for erosion. • If on-site soil meets criteria for engineered fill, use soil from foundation excavations (drilled pier and/or shallow spread footing) to reduce the need to transport material off site or import material for fill. Any imported fill must be certified weed-seed-free and approved by the Resources Management Division prior to bringing material into the park. • Have foundation installation equipment available during construction to allow for excavation or drilling through the large-diameter boulders anticipated to be scattered throughout the proposed development area. • Use semipermeable materials on temporary access routes to allow for water infiltration through the soil column and aeration of any compacted soils at the completion of construction. • Develop and implement a stormwater pollution prevention plan to control erosion and sedimentation, both during and after construction, thereby reducing water pollution. • Place construction debris in refuse containers at least daily. • Dispose of refuse at least weekly. Do not burn or bury refuse inside the park. • Schedule construction activities, particularly those resulting in substantial soil disturbance, during periods of low precipitation and low groundwater, when feasible, to reduce the risk of accidental hydrocarbon leaks or spills reaching surface and/or groundwater, to reduce the potential for soil contamination, and to minimize erosion of loose materials in construction areas. • Dispose of volatile wastes and oils in approved containers for removal from construction sites to avoid contamination of soils, drainages, and watercourses. • Inspect equipment for hydraulic and oil leaks prior to use on construction sites, and implement inspection schedules to prevent contamination of soil and water. • When using heavy equipment, keep absorbent pads, booms, and other materials on-site, so as to contain oil, hydraulic fluid, and solvents. • Site new facilities to avoid wetlands whenever practicable. • Use fencing to delineate wetlands within and adjacent to construction areas that would not be directly filled and mark the areas as sensitive habitat prior to the start of construction to prevent unintended trampling of wetland vegetation by construction personnel and equipment. If construction activities require dewatering or excavation along sloped areas, use silt fencing or hay bales if appropriate to prevent sedimentation of wetlands adjacent to construction. • Plant native shrubs and groundcover along the drainages to reduce sedimentation. • Construct bridges and install culverts when there is no water in the watercourses. Revegetate disturbed areas, as appropriate, and minimize erosion. • Install all bridge abutments and any protective materials outside the mapped wetland or watercourse area to eliminate fill in wetland area except in areas specifically identified in these findings. • Design all new culvert installations as bottomless culverts that completely span the mapped wetland area and allow the establishment of natural streambed conditions within the culvert. • Develop revegetation plans for any disturbed area, requiring the use of native species from the same gene pool. Specify soil preparation, native seed/plant mixes, and mulching for all areas disturbed by construction activities. • Develop and implement a monitoring plan to ensure successful revegetation, maintain plantings, and replace unsuccessful plant materials. • Salvage vegetation to the extent possible for use in revegetating disturbed areas. • Enforce construction specifications regarding soil salvage and reuse, trenching, plant protection, and finished grading. • Site buildings, trails, and campsites to minimize impacts to vegetation, and avoid large trees, where possible. • Select base course and fill materials for compatibility with native granitic soils to minimize the risk of introducing non-native plant seeds. Monitor areas where fill is imported from outside the park, and eradicate non-native plants. Apply standard techniques to prevent non-native plant encroachment. • Develop monitoring and mitigation plans for managing non-native plants within and immediately surrounding construction and developed areas. • Confine all construction operations to specified project work limits. Install temporary barriers to protect natural surroundings (including trees, plants, and root zones) from damage. Repair or replace damaged trees and plants. • Install fencing to minimize use of highly sensitive sites such as river edges, and install signs as needed to direct use to more appropriate areas. Placement of fencing and signs would be developed in consultation with cultural resources staff. • Use native or seed-free mulch to minimize surface erosion and introduction of non-native plants. • Comply with the Vegetation Management Plan (NPS 1997 b), including minimization of irrigation systems, planting with native plant species appropriate to the site, or landscaping (if appropriate) with approved nonspreading, non-native plants for restoration of disturbed areas. Treatment within historic districts would be in accordance with The Secretary of the Interior's Standards for Archeology and Historic Preservation (USDOI 1983 ) and The Secretary of the Interior's Standards for the Treatment of Historic Properties with Guidelines for the Treatment of Cultural Landscapes (USDOI 1996 ). • When approval is granted for removal of trees, measures to protect park resources may include, but are not limited to, site avoidance, the establishment of an equipment exclusion zone, directional falling of adjacent trees away from the site area, use of rubber-tired equipment only, or restrictions on piling and burning of slash on site. Proposed Compensation No off-site compensation is required for the first phase of this project, which would only involve fill of 0 . 002 acre of artificial wetlands that are isolated from established other waters. Later phases of the proposed action (both Alternatives 2 and 3 ) would enable the restoration of approximately 1 acre of existing disturbed wetland habitat, while they would result in the fill of a total of 0 . 010 to 0 . 015 acre of identified wetland habitat. The proposed action would have a long-term, moderate, beneficial effect on wetlands in Yosemite Valley through actions such as restoration of a portion of Lower Pines Campgrounds to natural conditions. Nonwetland Alternatives to the Proposed Action Curry Village and East Yosemite Valley Campgrounds Improvements Project actions would occur within the Merced River corridor, and within riverine, palustrine forest, palustrine scrub shrub, and palustrine emergent habitat. The purpose of the Curry Village and East Yosemite Valley Campgrounds Improvements Project is to provide detailed location, program, and design criteria for the Yosemite Valley Plan– approved actions in Curry Village and the east Yosemite Valley campground areas. There are no alternatives to the proposed action that could be located outside the floodplain or wetland and aquatic habitat of the Merced River corridor. Developing areas in the unclassified zone was considered because of potential benefits to the overall visitor experience and the reduced amount of tree removal that would be required. In Upper Pines, alternatives were developed that sited the walk-in sites outside of the development zones designated in the Yosemite Valley Plan. This scheme provided parking near the campsites in two smaller areas instead of concentrating parking in one larger lot and reduced the number of trees that would need to be removed. However, locating campsites outside of the designated development zones did not comply with the Yosemite Valley Plan . At South Camp, layouts were explored that located walk-in sites in an unclassified zone north of the proposed recreational vehicle dump station. This allowed for more separation of the group sites and a larger buffer between the walk-in sites and the proposed central shower facility. It also avoided wetlands in South Camp and reduced the amount of tree removal and clearing native vegetation. Locating campsites in the unclassified zone did not comply with the Merced River Plan, which designated the area for day use only. Because the alternative layouts did not comply with the Yosemite Valley Plan or the Merced River Plan, the alternative was dismissed from further analysis. New Development With the exception of South Camp, the Curry Village and East Yosemite Valley Campgrounds Improvements Project proposes the development of visitor facilities in developed areas. Additional wetland fill that would occur to accommodate the Mountain Shop would likewise be compensated by the restoration of existing disturbed wetland areas in the Lower Pines campground area. Existing Development Yosemite Valley visitor facilities are currently located throughout the Valley including through wetland areas and in areas identified for ecological restoration. The Curry Village and East Yosemite Valley Campgrounds Improvements Project proposes development in previously developed areas. Redevelopment The Curry Village and East Yosemite Valley Campgrounds Improvements Project proposes the development of visitor facilities primarily in developed areas. This includes use of existing facilities and existing and proposed roadways and trails, as well as existing utility corridors. The proposed action would have a beneficial, long-term impact on the extent, function, and value of wetlands due to wetland restoration. The proposed action would facilitate future restoration activities proposed in the Yosemite Valley Plan for these areas. The National Park Service has determined that there is no practicable alternative that could be located outside the floodplain or wetland habitat. Mitigation and compliance with regulations and policies to prevent impacts to water quality, wetland function and values, and loss of property or human life would be strictly adhered to during and after construction. ndividual permits with other federal and cooperating state and local agencies will be obtained or updated as appropriate prior to construction and removal activities. Minor adverse impacts to wetlands would occur from implementation of the preferred alternative. This impact includes a total fill of 0 . 015 acre of identified wetland areas, including 0 . 007 acre of isolated waters of which 0 . 002 acre is an artificial channel. In addition, restoration of approximately one acre of currently disturbed wetlands in Lower Pines campground would be enabled by the preferred alternative. Therefore, the National Park Service finds the proposed action to be acceptable under Executive Order 11990 for the protection of wetlands. |
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| Finding of No Significant Impact (main) - Letter from the Superintendent - Finding of No Significant Impact (table of contents) - Finding of No Significant Impact (document) - Wetland Statement of Findings - Floodplain Statement of Findings - Environmental Assessment Errata and Response to Substantive Comments |
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