Evaluation Criteria

Project Data

DEFINE THE PROPOSED ACTIVITY

Project proponent

National Park Service, Yosemite National Park

Purpose and need for the project

The purpose of the East Yosemite Valley Utilities Improvement Plan is to develop integrated utility corridors located in environmentally preferable areas, and to reduce utility infrastructure located in environmentally sensitive areas. The proposed project would reduce utility infrastructure within the River Protection Overlay and within adjacent areas proposed for ecological restoration.

Geographic location of the project

The East Yosemite Valley Utilities Improvement Plan will include improvements located primarily within the eastern portion of Yosemite Valley, from the water storage facility south of Happy Isles to the Yosemite Lodge area.

Project description

The proposed action includes construction of integrated utility corridors located in existing utility corridors and along existing or proposed transportation corridors; a reduction in the number of Merced River and major tributary utility crossings; a reduction in the amount of utility infrastructure located within the River Protection Overlay; and removal or abandonment of utility infrastructure located within riparian areas proposed for ecological restoration.

Refer to the description of the preferred alternative (Alternative 2) in the East Yosemite Valley Utilities Improvement Plan Environmental Assessment, Chapter II.

Duration of the proposed activities

Implementation of the East Yosemite Valley Utilities Improvement Plan would occur in phases over the next 10 years. Phase 1 would begin in the fall of 2003 and would include construction of the proposed Merced River crossing. In-channel work, bank stabilization, and revegetation would be completed within a two- to three-month period during the fall of 2003 (September through November) when the flow of the Merced River is typically lowest (less than 200 cubic feet per second). Phase 2 of the East Yosemite Valley Utilities Improvement Plan is expected to begin in January 2004 and would be coordinated with reconstruction activities proposed for the east Valley campgrounds. Later phases of the proposed project would occur as redevelopment occurs in other areas. For example, removal of river crossings and utility infrastructure in meadow areas identified for restoration would be coordinated with ecological restoration activities in these areas.

Magnitude and/or extent of the proposed activities

The East Yosemite Valley Utilities Improvement Plan proposes development of integrated utility corridors and relocation of utility infrastructure out of environmentally sensitive areas and into environmentally preferable areas. The East Yosemite Valley Utilities Improvement Plan proposes one new Merced River utility corridor crossing and alteration of two additional Merced River utility crossings. It also proposes removal of several existing Merced River crossings and major tributary crossings. Refer to the East Yosemite Valley Utilities Improvement Plan Environmental Assessment, Chapter IV, Environmental Consequences, for detailed data concerning potential impacts of the proposed action.

Mitigation

The East Yosemite Valley Utilities Improvement Plan is designed to locate utility infrastructure in environmentally preferable areas, reducing utility crossings of the Merced River and major tributaries, as well as removing or abandoning utility infrastructure in areas identified for ecological restoration in the Yosemite Valley Plan. Mitigation (e.g., Best Management Practices and resource-specific measures) is incorporated into the proposed action. Refer to the East Yosemite Valley Utilities Improvement Plan Environmental Assessment, Chapter II, Alternatives, for mitigation measures incorporated into the proposed action.

Evaluation Criteria

Project Data

DEFINE THE PROPOSED ACTIVITY

Relationship to past and future management activities

The Yosemite Valley Plan calls for utility relocation to reduce impacts to environmentally sensitive areas and to provide efficient utility service to areas identified for redevelopment. The East Yosemite Valley Utilities Improvement Plan is consistent with the Yosemite Valley Plan. The proposed action is also consistent with the Wild and Scenic River guidance provided in the Merced River Plan. Implementation of the proposed action and associated actions under the Yosemite Valley Plan would enhance the free flow of the river and riparian and floodplain extent, functions, and values. The proposed action would have a beneficial effect on the biological and hydrologic processes of the river.

DESCRIBE WHETHER THE PROPOSED ACTIVITY WILL DIRECTLY ALTER WITHIN-CHANNEL CONDITIONS

The position of the proposed activity relative to the streambed and streambanks

The East Yosemite Valley Utilities Improvement Plan implementation activities would occur throughout the east Valley. Both construction and removal of utility infrastructure will occur within the River Protection Overlay and within the bed and banks of the Merced River as well.

Any likely resulting changes in:

Active channel location

The East Yosemite Valley Utilities Improvement Plan will eliminate several existing utility lines that are buried beneath the Merced River riverbed. Three of these utility crossings are currently exposed and affect the natural flow of the Merced River. In addition, the proposed action will install one new consolidated Merced River utility crossing and replace two existing crossings. These crossings will be designed to minimize potential impacts to the river’s free flow and are not expected to adversely impact existing channel locations. The utility crossings will be placed approximately 8 feet below the riverbed, and the riverbed will be returned to the pre-existing contour.

Channel geometry (cross-sectional shape, width, depth characteristics)

The East Yosemite Valley Utilities Improvement Plan will eliminate several existing utility lines that are buried beneath the Merced River riverbed. Three of these utility crossings are currently exposed and affect the natural flow of the Merced River. In addition, the proposed action will install one new Merced River utility crossing and replace two existing crossings. These crossings will be designed to minimize impacts to the river’s free flow. The utility crossings will be placed approximately 8 feet below the riverbed and the riverbed will be returned to the pre-existing contour. Therefore, once constructed, the proposed action is not expected to create conditions that would alter existing channel geometry.

Channel slope (rate or nature of vertical drop)

As discussed above, the proposed action will eliminate several existing utility lines that are buried beneath the Merced River riverbed, install one new Merced River utility crossing, and replace two other existing crossings. These new crossings will be designed to minimize impacts to the river’s free flow. The utility crossings will be placed approximately 8 feet below the riverbed, and the riverbed will be returned to the pre-existing contour. Therefore, once constructed, the proposed action is not expected to create conditions that would have an adverse impact to or impede the river’s natural channel slope.

Channel form (straight, meandering, or braided)

The utility crossings will be placed approximately 8 feet below the riverbed. When construction activities have been completed, the riverbed will be returned to the pre-existing contour. Therefore, the proposed action is not expected to alter the rivers existing channel form.

Relevant water quality parameters (turbidity, temperature, nutrient availability)

During construction at periods of low water, turbidity impacts to the river would likely be small and would be mitigated through application of Best Management Practices. Refer to the East Yosemite Valley Utilities Improvement Plan Environmental Assessment, Chapter II, Alternatives, for mitigation measures incorporated into the proposed action. Once construction is completed, the proposed action would have no effect on river water quality.

Evaluation Criteria

Project Data

DESCRIBE WHETHER THE PROPOSED ACTIVITY WILL DIRECTLY ALTER WITHIN-CHANNEL CONDITIONS

Navigation of the river

River navigation as defined by the U.S. Army Corps of Engineers is not applicable to this section of the river. Only 20 miles of the Merced River, from its confluence with the San Joaquin River, is designated as navigable by the U.S. Army Corps of Engineers.

DESCRIBE WHETHER THE PROPOSED ACTIVITY WILL DIRECTLY ALTER RIPARIAN AND/OR FLOODPLAIN CONDITIONS

The position of the proposed activity relative to the riparian area and floodplain

The East Yosemite Valley Utilities Improvement Plan proposes actions throughout the east Valley. The overall affect of the proposed action is to reduce utility infrastructure within the riparian area and floodplain. Utility infrastructure may be removed or abandoned in riparian areas identified for ecological restoration.

Any likely resulting changes in:

Vegetation composition, age structure, quantity, or vigor

Construction activities will result in short-term loss of vegetation in construction areas. The reduction of utility infrastructure in areas identified for ecological restoration should result in long-term beneficial affects on vegetation. Refer to the East Yosemite Valley Utilities Improvement Plan Environmental Assessment, Chapter IV, Environmental Consequences, for a detailed discussion of impacts to vegetation.

Relevant soil properties such as compaction or percent bare ground

Construction activities will result in minor short-term adverse impacts to soils in construction areas where riparian or floodplain conditions exist. The reduction of utility infrastructure in areas identified for ecological restoration should result in long-term beneficial affects on soils. Refer to the East Yosemite Valley Utilities Improvement Plan Environmental Assessment, Chapter IV, Environmental Consequences, for a detailed discussion of impacts to soils.

Relevant floodplain properties such as width, roughness, bank stability, or susceptibility to erosion

Implementation of the East Yosemite Valley Utilities Improvement Plan will result in a reduction of utility infrastructure within the floodplain. The reduction in utility crossings of the river would be expected to have long-term beneficial effects on bank stability and erosion in the areas where utility crossings are removed. Refer to the East Yosemite Valley Utilities Improvement Plan Environmental Assessment, Chapter IV, Environmental Consequences, for a detailed discussion of impacts to floodplains.

DESCRIBE WHETHER THE PROPOSED ACTIVITY WILL DIRECTLY ALTER UPLAND CONDITIONS

The position of the proposed activity relative to the uplands

Implementation of the East Yosemite Valley Utilities Improvement Plan will include construction of integrated utility corridors in upland areas. Utility corridors have been located, where possible, in previously disturbed areas such as utility and transportation corridors. Refer to the East Yosemite Valley Utilities Improvement Plan Environmental Assessment, Chapter IV, Environmental Consequences, for a detailed discussion of impacts to uplands.

Any likely resulting changes in:

Vegetation composition, age structure, quantity, or vigor

Construction activities will result in short term impacts to upland vegetation. Corridors have been located in previously disturbed areas, where possible. The Phase 1 utility corridor construction could result in minor impacts to upland vegetation in the Camp 6 area. Refer to the East Yosemite Valley Utilities Improvement Plan Environmental Assessment, Chapter IV, Environmental Consequences for a detailed discussion of impacts to vegetation.

Relevant soil properties such as compaction or percent bare ground

Construction activities will result in short-term impacts to soils in construction areas. The reduction of utility infrastructure in areas identified for ecological restoration should result in long term beneficial affects on soils. Refer to the East Yosemite Valley Utilities Improvement Plan Environmental Assessment, Chapter IV, Environmental Consequences, for a detailed discussion of impacts to soils.

Evaluation Criteria

Project Data

DESCRIBE WHETHER THE PROPOSED ACTIVITY WILL DIRECTLY ALTER UPLAND CONDITIONS

Relevant hydrologic properties such as drainage patterns or the character of surface and subsurface flows

Hydrologic properties would improve in areas designated for ecological restoration where utilities would be removed. In other areas, construction mitigation measures designed to protect hydrologic properties include salvage and reuse of soils excavated and recontouring of construction areas to pre-existing contours.

Potential changes in upland conditions that would influence archeological, cultural, or other identified significant resource values

Construction activities would be performed in accordance with stipulations in the parkwide 1999 Programmatic Agreement and the 1986 Memorandum of Agreement. The proposed action would not influence archeological, cultural, or other identified significant resource values in uplands of the Merced River.

EVALUATE AND DESCRIBE WHETHER CHANGES IN ON-SITE CONDITIONS CAN OR WILL ALTER EXISTING HYDROLOGIC OR BIOLOGIC PROCESSES

The ability of the channel to change course, re-occupy former segments, or inundate its floodplain

The project would reduce utility infrastructure within the riverbed and adjacent floodplains. The proposed action would not enhance or impede the ability of the river to inundate the floodplain.

Streambank erosion potential, sediment routing and deposition, or debris loading

The project would reduce utility infrastructure within the riverbed, including utility crossings that are currently exposed. The proposed action would also reduce the need for access to the riverbank and riverbed areas for utility maintenance and repairs. This would be expected to reduce the potential for streambank erosion, sediment routing and deposition or debris loading over the long-term.

The amount or timing of flow in the channel

The proposed project would not affect the amount or timing of flow in the Merced River.

Existing flow patterns

Removal of exposed utility crossings in the Merced River and major tributaries will help allow the river to return to more natural flow patterns. New construction would be placed well below existing river channel depths and would not impede existing flow patterns.

Surface and subsurface flow characteristics

The proposed project is not expected to result in significant changes to surface and subsurface flow characteristics.

Flood storage (detention storage)

The proposed action is not expected to have a measurable effect on river flood storage capability.

Aggregation and or degradation of the channel

The proposed action is not expected to have a measurable effect on aggregation and/or degradation of the river’s natural channel properties.

Biological processes such as:

Reproduction, vigor, growth, and/or succession of streamside vegetation

Implementation of the East Yosemite Valley Utilities Improvement Plan would reduce utility infrastructure within the riverbed and adjacent riparian areas.

Nutrient cycling

The proposed project is not expected to have a measurable effect on natural nutrient cycling processes.

Fish spawning and/or rearing success

The proposed action would result in a reduction of utility infrastructure within the riverbed and adjacent areas. The project would enhance the free-flowing condition of the Merced River and the biological integrity of this segment for native fish and wildlife.

Riparian-dependent avian species needs

The reduction of utility infrastructure within riparian areas would reduce future impacts to these areas and enhance riparian habitats.

Evaluation Criteria

Project Data

EVALUATE AND DESCRIBE WHETHER CHANGES IN ON-SITE CONDITIONS CAN OR WILL ALTER EXISTING HYDROLOGIC OR BIOLOGIC PROCESSES

Amphibian/mollusk needs

In-channel construction activities could result in short-term impacts to amphibians or mollusks at utility crossing sites. Mitigation measures (e.g., Best Management Practices, species-specific monitoring) would reduce the identified effects to a negligible intensity. Refer to the East Yosemite Valley Utilities Improvement Plan Environmental Assessment, Chapter II, Alternatives, for mitigation measures incorporated into the proposed action. Over the long term, the reduction of utility infrastructure within the riverbed and adjacent areas would have a beneficial impact on habitat for species of amphibians and mollusks native to the Merced River.

Species composition (diversity)

Reduction of utility infrastructure within the riverbed and adjacent areas would enhance riparian habitat and have a beneficial effect on species composition.

ESTIMATE THE MAGNITUDE AND SPATIAL EXTENT OF POTENTIAL OFF-SITE CHANGES

Consider and document:

Changes that influence other parts of the river system

Implementation of the East Yosemite Valley Utilities Improvement Plan will occur throughout the Valley, and will result in temporary localized construction-related affects that are not expected to adversely affect the river long-term. The removal of utilities in areas slated for ecological restoration will enhance hydrologic processes in these areas that could result in a positive influence on the river system.

The range of circumstances under which off-site changes might occur (for example, as may be related to flow frequency)

Implementation of the East Yosemite Valley Utilities Improvement Plan is not expected to create circumstances under which changes in off-site would result in impairment of natural river flow frequencies or volumes.

The likelihood that predicted changes will be realized

The changes associated with a reduction of utility crossings in the Merced River and other environmentally sensitive area would be realized upon full implementation of the project.

Specify processes involved, such as water and sediment, and the movement of nutrients

Natural fluvial processes such as free flow, sediment transport, and nutrient exchange would be enhanced upon completion of the proposed action.

DEFINE THE TIME SCALE OVER WHICH STEPS 3-6 ARE LIKELY TO OCCUR

Review steps 3-6, looking independently at the element of time. Define and document the time scale over which the effects will occur.

In-channel work, bank stabilization, and revegetation for Phase 1 of the East Yosemite Valley Utilities Improvement Plan would be completed within a 2- to 3-month period during the fall of 2003 (September through November) when the flow of the Merced River is typically lowest (less than 200 cubic feet per second). Other construction within the river is planned in Phase 2 and Phase 3 of the project. All river work will occur during low flow. The overall project duration would be up to 10 years.

Scientific – The entire river corridor constitutes a highly significant scientific resource because the river watershed is largely within designated Wilderness in Yosemite National Park. Scientific Outstandingly Remarkable Values relate to the Merced River’s value for research. This Outstandingly Remarkable Value applies to all the Merced River segments.

The proposed action would have no effect on scientific resources of the river. The number of Merced River utility crossings would be reduced and remaining crossings would be placed far enough under the surface to leave flow unimpeded. Therefore, scientific values of the river would continue to be protected and enhanced.

Scenic – The Valley segment provides magnificent views from the river and its banks of waterfalls (Nevada, Vernal, Illilouette, Yosemite, Sentinel, Ribbon, Bridalveil, and Silver Strand), rock cliffs (Half Dome, North Dome/Washington Column, Glacier Point, Yosemite Point/Lost Arrow Spire, Sentinel Rock, Three Brothers, Cathedral Rock, and El Capitan), and meadows (Stoneman, Ahwahnee, Cook’s, Sentinel, Leidig, El Capitan, and Bridalveil). There is a scenic interface of river, rock, meadow, and forest throughout the segment.

The proposed action would result in a reduction in the number of Merced River utility crossings. The proposed action would remove or replace utility river crossings that are currently exposed in the Merced River. The proposed new crossing would be placed 8 feet under the riverbed. Although there may be short-term scenic impacts during construction, the proposed action would result in reducing future scenic impacts related to maintenance and repair work on the 13 existing crossings. Therefore, the proposed action would enhance the scenic Outstandingly Remarkable Value on a segment-wide basis.

Geologic Processes/Conditions – The Valley segment contains a classic, glaciated, U-shaped valley, providing important examples of a mature meandering river; hanging valleys such as Yosemite and Bridalveil Creeks; and evidence of glaciation (e.g., moraines below El Capitan and Bridalveil Meadows.

The proposed action would have no effect on the geologic process Outstandingly Remarkable Value. The proposed action would result in a reduction in the number of Merced River utility crossings The proposed action would remove or replace utility river crossings that are currently exposed in the Merced River and the proposed new crossing would be placed 8 feet under the riverbed. The proposed action would not affect the meandering of the river, the hanging valleys, or the evidence of glaciation. These values would continue to be protected and enhanced.

Recreation – The Valley segment offers opportunities to experience a spectrum of river-related recreational activities, from nature study and sightseeing to hiking. Yosemite Valley is one of the premier outdoor recreation areas in the world.

The proposed action would result in a reduction in the number of Merced River utility crossings The proposed action would remove or replace utility river crossings that are currently exposed in the Merced River. The proposed action would remove or replace utility river crossings that are currently exposed in the Merced River and the proposed new crossing would be placed 8 feet under the riverbed with the riverbed then returned to its pre-construction elevation and contours. Reduction of the number of utility river crossings will reduce the need for future utility repairs in the riverbed and on the riverbanks. This will enhance river-related recreational opportunities and have a beneficial effect on the recreation Outstandingly Remarkable Value for the Valley segment.

Biological – Riparian areas and low-elevation meadows are the most productive communities in Yosemite Valley. The high quality and large extent of riparian, wetland, and other riverine areas provide rich habitat for a diversity of river-related species, including special-status species, neotropical migrant songbirds, and numerous bat species.

The proposed action would have short-term, adverse, effects to riparian and aquatic habitat in the Valley segment related to construction of the proposed new utility river crossing, replacement of two other utility river crossings, and removal of several utility river crossings. Implementation of Best Management Practices and site restoration would result in minor effects. Refer to the East Yosemite Valley Utilities Improvement Plan Environmental Assessment, Chapter II, Alternatives, for mitigation measures incorporated into the proposed action. Removal of existing utility infrastructure within the areas designated for ecological restoration is expected to enhance the mixture of riparian and wetland habitats in the east Valley segment of the river. This would have a beneficial effect on the biological Outstandingly Remarkable Value for the Valley segment of the river.

Cultural – The Valley segment contains evidence of thousands of years of human occupation reflected in a large number of archeological sites and continuing traditional use today. Nationally significant historic resources are found here, such as designed landscapes and developed areas, historic buildings, and circulation systems (trails, roads, and bridges) that provide visitor access to the sublime views of natural features that are culturally valuable.

The proposed action would result in a reduction of utility infrastructure within environmentally areas and collocation of utilities into developed corridors sited to minimize environmental impacts. Due to the extent of cultural resources in the Valley, some utility construction and removals will occur in areas with potential for cultural resources. Impacts to archeological resources  will be mitigated through data recovery excavations, construction monitoring, and other implementation of other mitigation measures developed in consultation with culturally affiliated American Indians as specified in the 1999 Programmatic Agreement. Refer to the East Yosemite Valley Utilities Improvement Plan Environmental Assessment, Chapter II, Alternatives, for mitigation measures incorporated into the proposed action to address the potential for impacts to cultural resources. Through compliance with the stipulations in the 1999 Programmatic Agreement, adverse effects to the cultural Outstandingly Remarkable Value for the Valley segment will be mitigated.

Hydrologic Processes – The Valley segment is characterized by a meandering river, world-renowned waterfalls, an active flood regime, oxbows, unique wetlands, and fluvial processes.

The proposed action will reduce the total number of utility river crossings. Existing utility river crossings that are exposed in the river would be removed or reburied beneath the riverbed. One new utility river crossing would be constructed and placed 8 feet under the riverbed. Utility line construction and removal could have short-term impacts on water quality in the river. These impacts will be minimized through timing construction in the riverbed and banks to take place during seasonal low water and by implementing Best Management Practices for erosion control and sedimentation. Refer to the East Yosemite Valley Utilities Improvement Plan Environmental Assessment, Chapter II, Alternatives, for mitigation measures incorporated into the proposed action. The reduction in the number of utility river crossings will reduce future riverbed and bank impacts associated with ongoing maintenance and repairs. Reduction of the utility crossings in the Merced River and removal or reconstruction of those utilities that are currently exposed in the river will enhance the free-flowing condition of the Merced River, enhancing its natural hydrologic regime. The reduction of utility infrastructure in the areas identified for ecological restoration and within the river’s floodplain will enhance the active flood regime, wetlands, and fluvial processes. The proposed action would enhance the hydrologic Outstandingly Remarkable Value for the Valley segment.