Yosemite Valley Plan SEIS, Volume IB Part 2, Irreversible & Irretrievable Commitments of Resources

IRREVERSIBLE AND IRRETRIEVABLE
COMMITMENTS OF RESOURCES

The irretrievable and irreversible commitments of resources that are associated with each alternative are summarized below. Irreversible commitments are those that cannot be reversed, except perhaps in the extreme long-term. Irretrievable commitments are those that are lost for a period of time.

Alternative 1

The irretrievable and irreversible commitments of resources associated with Alternative 1 are limited to the consumption of energy resources, because no specific actions would be taken to change any of the natural or cultural resources, visitor experience, or park operations.

ENERGY CONSUMPTION

Propane consumption would continue at an estimated rate of 260,000 gallons per year through the year 2015. The estimated combined annual motor fuel consumption in 2000 would be 3,136,000 gallons. This amount would be expected to decrease to an annual amount of 2,694,600 gallons of motor fuel by the year 2015 due to the incremental replacement of the vehicle fleet with vehicles having improved fuel economy.

Alternative 2

WETLANDS

Up to approximately 23 acres of potential wetlands in Yosemite Valley would be adversely affected as a result of the construction and redevelopment of new facilities. This represents an irretrievable commitment of this resource for at least the duration of this alternative. However, it would be possible to rehabilitate impacted wetland areas and return them to their preconstruction state at some point in the future.

SOILS

Up to 69 acres of soil would be adversely affected under this alternative as a result of the construction of new facilities in Yosemite Valley, and approximately eight acres of this impact would occur within highly valued resource soils. This represents an irretrievable commitment of this resource for at least the duration of this alternative. However, it would be possible to rehabilitate these impacted soil types and return them to their preconstruction state at some point in the future.

VEGETATION

Up to 75 acres of vegetation would be adversely affected in Yosemite Valley under this alternative as a result of the construction of new facilities. However, only 21 of these acres impacted would occur within highly valued resource vegetation types. About 80 acres would be affected outside of Yosemite Valley. This represents an irretrievable commitment of this resource for at least the duration of this alternative. However, it would be possible to rehabilitate impacted vegetation types and restore them to their preconstruction state at some point in the future.

WILDLIFE

Up to 75 acres of wildlife habitat would be adversely affected in Yosemite Valley under this alternative as a result of the redevelopment and construction of facilities. Approximately 21 of these acres would be highly valued resource habitat types. Approximately 80 acres would be affected outside of Yosemite Valley. Removal and degradation of habitat would affect the availability of food, cover, and reproductive sites for wildlife, and result in associated indirect human impacts from the use of the development. This represents an irretrievable commitment of these resources for at least the duration of this alternative. It would, however, be possible to restore impacted habitats to some semblance of their preconstruction state at some point in the future.

SPECIAL-STATUS WILDLIFE SPECIES

Adverse effects on 3 special-status wildlife species would have an irreversible impact as long as development under this alternative occupies habitat and causes local human disturbance. It would be possible to reverse these impacts at some future date if the development was removed and some semblance of the natural habitat was restored.

SPECIAL-STATUS PLANT SPECIES

Adverse and irretrievable impacts would occur to two park rare species. Trillium and common juniper would be affected by new development within existing populations. It would be possible to reverse these impacts at some future date if the development was removed and the habitat for these species was restored to natural conditions. Irreversible impacts would occur to one park rare species. Individual planted giant sequoias in Yosemite Valley could be removed during restoration and possibly redevelopment actions. None of these actions would affect the overall sustainability of giant sequoias within the park’s three naturally occurring groves, with negligible overall impacts on this species.

CULTURAL RESOURCES

The removal of historic structures and contributing elements of the cultural landscape plus the disturbance of archeological sites would have an irreversible impact. However, prior to the removal or disturbance of these resources, documentation and data recovery would be completed, thus maintaining the historical record and limiting the impact to the loss of the physical structure and historic associations. The disruption and destruction of traditional gathering areas and historic village sites also would have irreversible impacts; however, the National Park Service would continue to consult with associated American Indian tribes in an effort to minimize these impacts.

MERCED WILD AND SCENIC RIVER

The bank stabilization that may, depending on design, be necessary to reconstruct the El Portal Road between the Cascades Diversion Dam and Pohono Bridge would result in an irretrievable impact to the hydrologic process Outstandingly Remarkable Value because a portion of the river channel would be displaced by the stabilization material. The removal of historic bridges (i.e., Sugar Pine and Stoneman) would have an irreversible adverse impact to the cultural Outstandingly Remarkable Value.

ENERGY CONSUMPTION

Estimated annual propane consumption for the years 2000-2015 would be 405,800 gallons. The estimated combined annual motor fuel consumption by the year 2015 is 1,688,300 gallons.

Alternative 3

Under this alternative, no appreciable irreversible or irretrievable commitments of resources would be associated with water resources; floodplains; air quality; geologic hazards; scenic resources; noise; visitor experience; transportation; social and economic environments; or park operations. The irreversible and irretrievable impacts to special-status vegetation species, and to cultural resources would be the same as described for Alternative 2.

WETLANDS

Up to approximately 17 acres of potential wetlands in Yosemite Valley would be affected as the result of the construction and redevelopment of new facilities. This represents an irretrievable commitment of this resource for at least the duration of this alternative. However, it would be possible to rehabilitate impacted wetland areas and return them to their preconstruction state at some point in the future.

SOILS

Up to 98 acres of soil would be adversely affected under this alternative as a result of the construction of new facilities in Yosemite Valley. However, none of this impact would occur within highly valued resource soils. This represents an irretrievable commitment of this resource for at least the duration of this alternative. However, it would be possible to rehabilitate these impacted soil types and return them to their preconstruction state at some point in the future.

VEGETATION

Up to 99 acres of vegetation in Yosemite Valley would be adversely affected under this alternative as a result of the construction of new facilities. However, approximately 14 of these impacted acres would occur within highly valued resource vegetation types. About 37 acres of vegetation would be affected outside Yosemite Valley. This represents an irretrievable commitment of this resource for at least the duration of this alternative. However, it would be possible to rehabilitate impacted vegetation types and return them to their preconstruction state at some point in the future.

WILDLIFE

Up to 99 acres of wildlife habitat would be adversely affected in Yosemite Valley under this alternative as a result of the redevelopment and construction of facilities. Approximately 14 acres of this impacted area would occur in highly valued resource habitat types. Approximately 37 acres of habitat would be affected outside Yosemite Valley. Removal and degradation of habitat would affect the availability of food, cover, and reproductive sites for wildlife resulting in indirect impacts associated with use of the development. This represents an irretrievable commitment of these resources for at least the duration of this alternative. It would, however, be possible to restore impacted habitats to some semblance of their preconstruction state at some point in the future.

SPECIAL-STATUS WILDLIFE SPECIES

Adverse effects on 1 special-status wildlife species would have an irreversible impact as long as development under this alternative occupies habitat and causes local human disturbance. It would be possible to reverse these impacts at some future date if the development was removed and some semblance of the natural habitat was restored.

SPECIAL-STATUS PLANT SPECIES

Adverse and irretrievable impacts would occur to one park rare species. Common juniper would be affected by new development within existing populations. It would be possible to reverse these impacts at some future date if the development was removed and the habitat for these species was restored to natural conditions. Irreversible impacts would occur to one park rare species. Individual planted giant sequoias in Yosemite Valley could be removed during restoration and possibly redevelopment actions. None of these actions would affect the overall sustainability of giant sequoias within the park’s three naturally occurring groves, with negligible overall impacts on this species.

MERCED WILD AND SCENIC RIVER

The bank stabilization that may, depending on design, be necessary to reconstruct the El Portal Road between the Cascades Diversion Dam and Pohono Bridge would result in an irretrievable impact to the hydrologic process Outstandingly Remarkable Value because a portion of the river channel would be displaced by the stabilization material. The loss of historic bridges (i.e., Sugar Pine, Stoneman, Superintendent’s, and Housekeeping) would have an irreversible adverse impact to the cultural Outstandingly Remarkable Value. The removal of the former Superintendent’s House (Residence 1) and Lamon Orchard would result in an irretrievable impact to the cultural Outstandingly Remarkable Value.

ENERGY CONSUMPTION

Estimated annual propane consumption for the years 2000-2015 would be 380,310 gallons. The estimated combined annual motor fuel consumption by the year 2015 is 2,165,800 gallons.

Alternative 4

Under this alternative, no appreciable irreversible or irretrievable commitments of resources would be associated with water resources, floodplains, air quality, geologic hazards, scenic resources, visitor experience, transportation, noise, social and economic environments, or park operations. The irreversible and irretrievable impacts to special-status vegetation species, and cultural resources, would be the same as described for Alternative 2.

WETLANDS

Up to approximately 18 acres of potential wetlands would be affected as the result of the construction and redevelopment of new facilities. This represents an irretrievable commitment of this resource for at least the duration of this alternative. However, it would be possible to rehabilitate impacted wetland areas and return them to their preconstruction state at some point in the future.

SOILS

Up to 98 acres of soil would be adversely affected under this alternative as a result of the construction of new facilities in Yosemite Valley. However, none of this impact would occur within highly valued resource soil. This represents an irretrievable commitment of this resource for at least the duration of this alternative. However, it would be possible to rehabilitate these impacted soil types and return them to their preconstruction state at some point in the future.

VEGETATION

Up to 102 acres of vegetation in Yosemite Valley would be adversely affected under this alternative as a result of the construction and redevelopment of new facilities. However, approximately 14 of these impacted acres would occur within highly valued resource vegetation types. About 70 acres of vegetation would be affected outside of Yosemite Valley. This represents an irretrievable commitment of this resource for at least duration of this alternative. However, it would be possible to rehabilitate impacted vegetation types and return them to their preconstruction state at some point in the future.

WILDLIFE

Up to 102 acres of wildlife habitat would be adversely affected in Yosemite Valley under this alternative as a result of the redevelopment and construction of facilities. Approximately 14 of these acres would be highly valued resource habitat types. Approximately 70 acres of habitat would be affected outside Yosemite Valley. Removal and degradation of habitat would affect the availability of food, cover, and reproductive sites for wildlife, and result in associated indirect human impacts from the use of the development. This represents an irreversible commitment of these resources for at least the duration of this alternative. It would, however, be possible to restore impacted habitats to some semblance of their preconstruction state at some point in the future.

SPECIAL-STATUS WILDLIFE SPECIES

Adverse effects on 2 special-status wildlife species would have an irreversible impact as long as development under this alternative occupies habitat and causes local human disturbance. It would be possible to reverse these impacts at some future date if the development was removed and some semblance of the natural habitat was restored.

SPECIAL-STATUS PLANT SPECIES

Adverse and irretrievable impacts would occur to two park rare species. Common juniper and whitneya would be affected by new development within existing populations. It would be possible to reverse these impacts at some future date if the development was removed and the habitat for these species was restored to natural conditions. Irreversible impacts would occur to one park rare species. Individual planted giant sequoias in Yosemite Valley could be removed during restoration and possibly redevelopment actions. None of these actions would affect the overall sustainability of giant sequoias within the park’s three naturally occurring groves, with negligible overall impacts on this species.

MERCED WILD AND SCENIC RIVER

The bank stabilization that may, depending on design, be necessary to reconstruct the El Portal Road between the Cascades Diversion Dam and Pohono Bridge would result in an irretrievable impact to the hydrologic process Outstandingly Remarkable Value because a portion of the river channel would be displaced by the stabilization material. The removal of historic bridges (i.e., Sugar Pine, Stoneman, Superintendent’s, and Housekeeping) would have an irreversible adverse impact to the cultural Outstandingly Remarkable Value. The removal of the former Superintendent’s House (Residence 1) would result in an irretrievable impact to the cultural Outstandingly Remarkable Value.

ENERGY CONSUMPTION

Estimated annual propane consumption for the years 2000-2015 would be 405,810 gallons. The estimated combined annual motor fuel consumption by the year 2015 is 1,644,100 gallons.

Alternative 5

There would be no significant irreversible or irretrievable commitments of resources associated with water resources, floodplains, air quality, geologic hazards, scenic resources, visitor experience, transportation, noise, social and economic environments, and park operations. The irreversible and irretrievable impacts to special-status vegetation species, and cultural resources would be the same as described for Alternative 2.

WETLANDS

Up to approximately 27 acres of potential wetlands would be affected as the result of the construction and redevelopment of new facilities. This represents an irretrievable commitment of this resource for at least the duration of this alternative. However, it would be possible to rehabilitate impacted wetland areas and return them to their preconstruction state at some point in the future.

SOILS

Up to 67 acres of soil would be adversely affected under this alternative as a result of the construction of new facilities in Yosemite Valley. However, approximately eight acres of this impact would occur within highly valued resource soil. This represents an irretrievable commitment of this resource for at least the duration of this alternative. However, it would be possible to rehabilitate these impacted soil types and return them to their preconstruction state at some point in the future.

VEGETATION

Up to 69 acres of vegetation in Yosemite Valley would be adversely affected under this alternative as a result of the construction and redevelopment of new facilities. However, approximately 16 of these impacted acres would occur within highly valued resource vegetation types. About 78 acres of vegetation would be affected outside Yosemite Valley. This represents an irretrievable commitment of this resource for at least the duration of this alternative. However, it would be possible to rehabilitate impacted vegetation types and return them to their preconstruction state at some point in the future.

WILDLIFE

Up to 69 acres of wildlife habitat would be adversely affected in Yosemite Valley under this alternative as a result of the redevelopment and construction of facilities. Approximately 16 of these acres would be highly valued resource habitat types. Approximately 78 acres of habitat would be affected outside Yosemite Valley. Removal and degradation of habitat would affect the availability of food, cover, and reproductive sites for wildlife, and result in associated indirect human impacts from the use of the development. This represents an irreversible commitment of these resources for at least the duration of this alternative. It would, however, be possible to restore impacted habitats to some semblance of their preconstruction state at some point in the future.

SPECIAL-STATUS WILDLIFE SPECIES

SPECIAL-STATUS PLANT SPECIES

Adverse and irretrievable impacts would occur to two park rare species. Trillium and common juniper would be affected by new development within existing populations. It would be possible to reverse these impacts at some future date if the development was removed and the habitat for these species was restored to natural conditions. Irreversible impacts would occur to one park rare species. Individual planted giant sequoias in Yosemite Valley would be removed during restoration and possibly redevelopment actions. None of these actions would affect the overall sustainability of giant sequoias within the park’s three naturally occurring groves, with negligible overall impacts on this species.

MERCED WILD AND SCENIC RIVER

The bank stabilization that may, depending on design, be necessary to reconstruct the El Portal Road between the Cascades Diversion Dam and Pohono Bridge would result in an irretrievable impact to the hydrologic process Outstandingly Remarkable Value because a portion of the river channel would be displaced by the stabilization material. The removal of historic bridges (i.e., Sugar Pine and Ahwahnee) would have an irreversible adverse impact to the cultural Outstandingly Remarkable Value. The removal of the former Superintendent’s House (Residence 1) would result in an irretrievable impact to the cultural Outstandingly Remarkable Value.

ENERGY CONSUMPTION

Estimated annual propane consumption for the years 2000-2015 would be 424,900 gallons. The estimated combined annual motor fuel consumption by the year 2015 is 1,872,000 gallons.

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