Yosemite Valley Plan SEIS, Volume III, Chapter 4: Part 1

Chapter 4 ~ Affected Environment and Environmental Consequences

Chapter 4 includes discussion of public comment concerning various aspects of the environment affected by Yosemite Valley planning efforts along with the environmental consequences of these efforts. Public concerns regarding natural, scenic, and cultural resources, special land designations, visitor experiences, transportation proposals, noise considerations, socioeconomic impacts, and Yosemite National Park operations and facilities are analyzed in this chapter.

Section 4.1 ~ Natural Resources

Restoration and preservation of the natural resources in Yosemite Valley is a concern for many individuals and organizations responding to the Draft Yosemite Valley Plan/SEIS. Their comments cover a wide range of resource subjects and encompass suggestions regarding management directions, needs for analysis, and additional topics for consideration. Analysis of concerns pertaining to water resources, wetlands, geology, vegetation, wildlife, and air quality are separated into individual sections in this chapter. In this section, the presentation of public comment focuses on general ecosystem processes.

The ecosystem restoration goals of the Draft Yosemite Valley Plan/SEIS generate diverse reactions from respondents. "Let’s not pretend that we can or should attempt to recreate ‘wilderness’ in our very domesticated Yosemite Valley," one person declares. Ecosystems are too dynamic to identify a condition of successful restoration, this individual suggests, thus the National Park System should emphasize visitor experience when evaluating resource management goals. Others identify visitor experience as a reason to advocate ecosystem restoration and preservation as a priority for park management. Claiming that many people who visit Yosemite National Park anticipate a natural setting, these individuals believe park patrons would prefer to see less commercial development. Specifically, some urge the National Park Service to complete ecosystem restoration projects on park-owned properties in Wawona. One conservation organization calls upon park planners to distinguish between upland benches and hillsides when evaluating the cumulative impacts of housing more park staff in El Portal.

40. Public Concern: The Yosemite Valley Plan should not emphasize natural restoration and preservation in Yosemite Valley.

"Yosemite Valley is not by any stretch of the imagination what is now called a ‘wilderness area.’ People killed off the major predators . . . in the 19th century. The Valley is covered with aggressive wildflowers and grasses and other plants that come from Europe and elsewhere. The notion of ‘restoration’ is essentially a bogus one, because the Valley can never be restored to its pre-European man situation unless we keep all people out for hundreds of years, after having done massive ecological damage with bulldozing and spraying herbicides to try to kill over all of the now-naturalized plants. . . It is a fools errand to undertake such a monumentally destructive effort. . . The whole notion of ‘environmental restoration’ is chasing the will ‘o the wisp. It is just another form of intensive non-organic gardening, masquerading under the guise of ‘ecology.’ The first thing that one learns when one studies ecology, is that all ecological systems are dynamic. Thing’s are constantly changing; the weather changes; outside pressures in the form of viruses, bacteria and fungi attack both plants and animals. People come from all over the world to see the amazing and sublime geology of Yosemite: the gray towers and sheer walls of granite that surround the narrow Valley. They do not come from all over the world to see native plants being gardened with herbicides being sprayed on their naturalized plant brothers and sisters. If Yosemite management wants to take out the bowling alley, fine. But let’s not pretend that we can or should attempt to re-create ‘wilderness’ in our very domesticated Yosemite Valley." (Individual, San Carlos, CA - #99)

Response: The goals of the 1980 General Management Plan, and thus the Yosemite Valley Plan, include allowing natural processes to prevail and protecting and enhancing natural resources. Yosemite National Park proposes to restore natural processes that maintain natural ecosystems in Yosemite Valley to help achieve these goals and objectives. This includes restoring soils to as near natural conditions as possible through decompaction of soils (facilitating oxygen and water infiltration into soils that are currently hydrophobic), adding native organic materials to areas that have been denuded and made barren by trampling and loss of litter and duff; restoration of natural hydrologic conditions through removal of structures that impede the natural flow of surface and subsurface water; restoration of topographic features (particularly old channels, oxbows, and depressions that have been filled in); reintroduction of surface fires that help break down surface litter deposits, recycle nutrients back into the soil, and maintain a more diverse mosaic of vegetation cover; and removal of non-native plant species that impede the re-establishment of native vegetation. All of these processes and features facilitate the re-establishment of natural vegetation cover. These methods have been successfully used for the past 15 years in Yosemite, with proven results.
(Also see responses to Public Concerns #48, #95, and #180.)

58. Public Concern: The Yosemite Valley Plan should emphasize preservation of natural resources in Yosemite Valley.

"I applaud your plans to increase and preserve meadows and natural resources throughout Yosemite Valley. Hikers, climbers, birders, and all naturalists will appreciate this effort. As much as possible, the natural rustic nature of Yosemite should be maintained. Upscale, modern commercial hotels can and will develop outside the Park and that is where they belong. Yosemite is known for its hiking, camping, climbing, and nature trails, all situated in a rustic, unspoiled natural environment of grandeur carved out of solid rock over eons of time. If you attempt to change that, you will ruin it." (Individual, Peoria, AZ - #100)

Response: Two principal goals of the Yosemite Valley Plan are the preservation and restoration of natural processes and the reclamation of natural beauty. These goals and associated criteria, as well as other goals and criteria for visitor experience and cultural resources are discussed in Vol. IA, Chapter 1, Purpose and Need, Direction for this Planning Effort. The various goals and criteria are intertwined and require balancing to ensure a successful plan.
(Also see responses to Public Concerns #48, #95, and #180.)

274. Public Concern: The National Park Service should restore Yosemite National Park Service lands in Wawona.

"If memory serves, during the ‘70’s when YNPS was actively pursuing and acquiring properties in Wawona, it was stated that these acquisitions would be torn down and the land returned to its ‘natural state.’ This legal mandate has not been included or addressed in the latest planning effort, and it still hasn’t been executed!" (Individual, No Address - #1355)

Response: Each of the action alternatives considered in the Final Yosemite Valley Plan/SEIS addresses only those park-owned lands within Section 35 in Wawona that are proposed for development to meet housing needs for employees. Other National Park Service lands in Wawona are outside the scope of this planning effort. However, it continues to be the goal of the National Park Service to restore previously developed lands within Section 35 to natural conditions as funding becomes available. Priorities will be placed on those properties that fall within the River Protection Overlay of the South Fork of the Merced River, in accordance with guidance and direction outlined in the Merced River Plan/FEIS, as well as those areas that are impacting potential wetland, riparian, and black oak woodland communities.

546. Public Concern: The Yosemite Valley Plan should consider the cumulative impacts of increased human population in El Portal on loss of rare upland bench habitat.

"The DVP does not consider the related and cumulative impacts of increasing human population in El Portal, leading to loss of rare Upland Bench habitat. The Draft VP does not distinguish the rare Upland Benches from the more abundant Hillsides and mistakenly says that the impacts to habitats and wildlife are ‘limited to relatively small areas of upland habitat loss in comparison to the amount of upland habitat present.’ Two of these rare benches are proposed for development — Hillside East and Hillside West — and are areas that need to be protected for both biological and cultural resources and need intensive non-native species removal efforts. All of the existing El Portal development except for upper Old El Portal is already on rare benches which have already sustained significant impacts to both biological and cultural resources." (Conservation Organization, Yosemite, CA - #7883)

Response: In El Portal, various physical and biotic factors combine to determine the assemblage of plant and animal species that occur in a certain site. Although "upland bench" is not recognized as a discrete plant community or wildlife habitat type under any system of classification, it is apparent that undeveloped sites of this slope and aspect are unusual features in the Merced River Canyon. This is primarily due to past development that has tended to occur on these relatively level areas, especially in El Portal. The questions are, however, whether these bench areas that remain undeveloped support unique assemblages of plant and animals species, and whether the value of these areas outweighs the protection and restoration of high-value habitats in Yosemite Valley that are only able to occur by moving facilities to El Portal. Thorough analysis of the tradeoffs inherent in the action alternatives in the Final Yosemite Valley Plan/SEIS has indicated that the answer is "no" to both of these questions.

The benches appear to support denser growths of the plant species that are prevalent on the surrounding hillsides and, therefore, are likely to support more abundant wildlife. But richer habitats are found in the drainages in El Portal and on the north-facing slopes on the south side of the river that would be unaffected by the actions included in the Final Yosemite Valley Plan/SEIS. All species of plants or wildlife that are found on benches are also found in these other habitats, and probably in greater abundance.

In a regional, cumulative context, riparian and meadow habitats are the most severely degraded types, both in Yosemite National Park and the Sierra Nevada. This fact, coupled with the proven high value of these habitats to large numbers of species, including many special-status species, has focused actions in the Final Yosemite Valley Plan/SEIS on protection and restoration of riparian and meadow habitats. This would require the removal of some facilities from Yosemite Valley and the development of replacement facilities in the El Portal Administrative Site, which was established in 1958 for just such a purpose. While such development in El Portal should be as environmentally sensitive as possible, some impacts would be unavoidable. However, overall actions would allow for the significant improvements to natural resources and visitor experience values.

Section 4.2 ~ Water Resources

This section of the document deals with those public concerns that address potential impacts to the water resources of Yosemite Valley. Respondents’ concerns regarding bridges and hydrology, dams and levees, floodplains, hydrogeomorphology, and the restoration of water resources are detailed within this section. The reader should note that public concerns addressing the historical and transportational values of bridges are contained, respectively, in the Section 4.9 ~ Cultural Resources and Section 4.13 ~ Transportation sections of this document. In addition, public concerns regarding any aspect of the Merced River’s Wild and Scenic designation are included in the Wild and Scenic River section of this document.

4.2.1 ~ Bridges and Hydrology

Bridge removal is a contentious subject that elicits numerous proclamations from Yosemite Valley Plan respondents. Some individuals and groups agree wholeheartedly that the historic bridges need to be removed to allow the Merced River to flow freely. Many others, however, disabuse the notion that the historic bridges actually cause a noticeable, negative impact on the river ecosystem. These respondents ask for clarification on the nature and extent of the bridges’ impacts. "If there actually is a reason for removal of the bridges based other than on riparian speculation, then they should be removed, but one wishes the reasons were more clearly demonstrated," ventures one opponent of bridge removal. "The proposal to remove the bridges implies that their effects are reversible," an individual proffers. "I can’t see that the presumed benefits of the removal of any of the bridges, uncertain and perhaps small as those benefits might be, outweigh their historic and aesthetic value."

Many members of the public perceive the removal of bridges as a rash, irreversible decision. Several individuals exhort the Park Service to consider mitigation of the bridges’ impacts on fluvial mechanics, including overflow channels and culverts, as an alternative to the complete removal of bridges. Rebuilding or restructuring the present bridges so as to ameliorate their negative impacts on hydrology is also offered by others as a way to avoid the bridges’ total demolition. Urging the National Park Service to look at the entire watershed for impacts and possibilities for mitigation, an historical preservation society affirms the use of mitigation over removal. "We are convinced," this organization contends, "that significant ecological restoration can take place without the removal of the historic bridges. We believe that the impacts of the historic bridges on the river ecosystem must be isolated from other impacts such as riprap and human tramping, and that these impacts be assessed objectively without predetermining bridge impacts to be by definition negative."

If the National Park Service does indeed go forward with the removal of the historic bridges, the impacts of such a massive undertaking within the Merced River’s ecosystem need to be evaluated and mitigated, according to some conservation groups. "Although our organization strongly supports the removal of several Yosemite bridges, these impediments should not be removed until the NPS has a plan to protect the river flows and hydrologic processes to the maximum extent feasible," one organization contends. Another conservation organization wonders how the construction of two new bridges will, according to the Draft Yosemite Valley Plan/SEIS, minimize adverse impacts on hydrology and water quality. The Plan "completely lacks description as to how this would occur," states this group.

168. Public Concern: The Yosemite Valley Plan should require the removal of bridges from Yosemite Valley.

"I am supportive of removing as many--as limited traffic circulation will allow--of the historic Merced River bridges. These bridges disturb the fluvial mechanics and natural flow of the river." (Individual, Mariposa, CA - #68)

Response: The action alternatives in the Final Yosemite Valley Plan/SEIS propose the removal of several bridges that have adverse impacts to the hydrologic processes of the Merced River (the bridges that are proposed for removal vary by alternative). Bridges can interfere with hydrologic processes by influencing the river’s width, location, and velocity and affect the river’s ability to meander and change course. For example, Sugar Pine Bridge has caused the formation of a cut-off channel, and arched bridges such as Stoneman and Sugar Pine Bridges confine flows and result in channel narrowing. Bridges that interfere with hydrologic processes are in conflict with the General Management Plan’s goal to "allow natural processes to prevail" and with the hydrologic process Outstandingly Remarkable Value of the Merced Wild and Scenic River. The Final Yosemite Valley Plan/SEIS explains the adverse impacts that bridges can have on the Merced River in Vol. IB, Chapter 4, Environmental Consequences. Further detail can be found in a number of studies that have evaluated impacts of bridges and other human alterations on the Merced River through Yosemite Valley, notably Madej (1991) and Milestone (1978).

However, beside these hydrologic effects, many of the bridges in Yosemite Valley exemplify the National Park Service Rustic Architectural Style and are an important component of the park’s physical history. They provide access across the river and are constructed to visually harmonize with the spectacular scenery of Yosemite Valley. They are listed in the National Register of Historic Places and are considered to be Outstandingly Remarkable Values of the Merced Wild and Scenic River. Therefore, the decision to remove any of these historic resources is a difficult one. The bridges were evaluated using two primary factors: the extent to which they degrade the hydrology of the river, and their continued use as important components of the traffic circulation system. The Final Yosemite Valley Plan/SEIS Preferred Alternative proposes removal of Sugar Pine Bridge and associated riverbank revetments, restoration of the riparian corridor, and evaluation of the continuing hydrologic impacts at Stoneman Bridge. If Stoneman Bridge continues to cause unacceptable damage to the river system, this bridge would then be removed.

229. Public Concern: The Yosemite Valley Plan should clarify the negative impacts of bridges on the Merced River.

"As for the bridges, one wishes there were more convincing evidence of their negative impact on the river than a general discussion of their ‘restricting run-off flows so as to narrow the river from its former broad riparian habitat.’ From my scanning of the old photos (which one suspects are quite selective), any ‘narrowing’ seems somewhat obscure. Furthermore, if the Stoneman Bridge ‘obstructs the flow and dynamics of the river’ so as to cause less flooding below and consequent curtailment of meadow formation, why is it also considered an error to have dynamited the El Capitan moraine years ago, which would seem to have opened up the passage of the river as is wished for the Stoneman Bridge venue. If there actually is a reason for removal of the bridges based other than on riparian speculation, then they should be removed but one wishes it were more clearly demonstrated." (Individual, Sanger, CA - #2293)

"I accept the assertion that the bridges affect (or at least have affected) the morphology of the river. However to my untrained eye things don’t look all that different from the way they looked 65 years ago. There is still a sand bar upstream of Housekeeping, and there is still a big water hole by Stoneman Bridge. Haven’t the effects of the bridges stabilized? And have the effects been all that disastrous? The proposal to remove the bridges implies that their effects are reversible, that by removing them the river will revert to its pre-bridge conditions. Is that known, is hydrology such an exact science that such things can be predicted with reasonable certainty? Removal of the bridges replaces known existing effects with unknown or uncertain future effects. That’s scary! I can’t see that the presumed benefits of removal of any of the bridges, uncertain and perhaps small as those benefits might be, outweighs their historic and aesthetic value. But if you save any of them, let one be Stoneman Bridge." (Individual, Oakland, CA - #7749)

"The demolition of any of the historic bridges in Yosemite Valley would result in significant and unmitigated direct and cumulative adverse impacts to significant historical, architectural and scenic resources. Although the proposed demolition of the historical bridges is to ‘allow the river to meander and change course naturally,’ the fact of the matter is that these bridges have existed in one form or another since the late 1890s and certainly since the 1920s and the 1930s. The ‘course and path’ of the river is already well established with these bridges in place. Further, the impact of these bridges to the river is not measurably different than the large ‘bus size’ boulders and other debris which has landed in the rivers over the many centuries." (Business, San Diego, CA - #7884)

Response: The Merced River in eastern Yosemite Valley is an alluvial river, where the bed and banks are made up of the same materials that are transported by the river. This makes for dynamic channel conditions as natural erosion and deposition processes cause the river channel to migrate, often over an extensive area. The inherent dynamic nature of alluvial rivers make their coexistence with stationary bridges problematic. Exacerbating this situation is the fact that the bridge itself may cause flow-related changes that result in morphologic changes to the channel.

Hydrologic conditions pertain to the quantity and timing of flow and hydraulic conditions to factors such as depth, velocity, and erosive power, etc. Since alluvial rivers flow through erodible materials, they form channels with characteristics, e.g., width/depth ratio, flow capacity, sinuosity, slope, etc., determined by such factors as flow regime, sediment transport, and valley slope. Additionally, the development of floodplain areas is a characteristic of alluvial rivers. When hydrologic and/or hydraulic conditions change, either through natural or human causes, river channels adjust by erosion and sedimentation processes until stable morphologic characteristics and dimensions can redevelop. Bridges can cause river morphology to adjust by, among other factors, changing the rate, depth, and velocity of flow in the vicinity of the structure.

Bridges rarely span the entire floodplain width of alluvial rivers and do not generally even span the entire natural channel width and, therefore, constrict flow area. During floods this results in a portion of flow that would normally use floodplain areas to be forced under the structure, increasing the amount of discharge experienced by the channel. The higher discharge and reduced flow area cause a backwater effect (a deep, slow velocity area) to form upstream and high velocities to occur near and under the bridge opening.

The effect of these seemingly minor flow-related changes can be profound, both upstream and downstream of the bridge. The reach upstream of the bridge (in the backwater zone) will often develop a mid-channel bar as sediment in transport deposits due to the reduction in velocity. The development of a mid-channel bar can lead to bank instability as the force of the river is directed laterally away from the bar and into the bank. If lateral erosion is permitted to occur, eventual failure of banks that have been stabilized by riparian vegetation may result and cause rapid movement of large quantities of sediment and vegetative debris and possible channel avulsion. In certain cases, such as a Sugar Pine Bridge, lateral instability and the increase of surface water elevation upstream of the bridge can encourage development of a new channel that cuts off a river meander causing many other problems and impacts. In the reaches downstream of the bridge (and also immediately upstream), flow velocity is high. This can cause scour of the banks that form the transition from natural river width to bridge opening width. Directly beneath the bridge velocities are at a maximum and scour is very common. Downstream of the bridge, a mid-channel bar is likely to develop as scoured sediments drop out in the lower velocity environment. As with development of a mid-channel bar upstream of a bridge, lateral channel instability and associated riparian zone problems can result.

The Final Yosemite Valley Plan/SEIS explains the adverse impacts that bridges can have on the Merced River in Vol. IA, Chapter 3, Affected Environment, and Vol. IB, Chapter 4, Environmental Consequences. Further detail can be found in a number of studies that have been conducted looking at the impacts of bridges and other human alternations on the Merced River through Yosemite Valley, notably Madej (1991) and Milestone (1978).

565. Public Concern: The Yosemite Valley Plan should mitigate impacts caused by Merced River bridges.

"In the event that it is determined in the future that a bridge is doing quantifiable harm to the ecosystem, other bridge-related actions should be attempted first. The feasibility of creating overflow channels around bridges or installing culverts under the bridge abutments that would relieve the impacts of the bridges during high water flows are examples of possible remedies." (Non-Governmental Organization, San Francisco, CA - #7885)

Response: Consistent with the 1980 General Management Plan to allow natural processes to prevail, and to protect the hydrologic process Outstandingly Remarkable Values of the Merced Wild and Scenic River, the National Park Service strives to allow the Merced River to meander, change course, and make other changes through uninterrupted, unaltered hydrologic processes: erosion, deposition, winter flooding, spring runoff, large woody debris in the river channel, etc. Bridges and their abutments interrupt these hydrologic processes, particularly when the abutments are in the river channel and when they do not accommodate flood flows.

The National Park Service has considered modifying the existing bridges, but based on current analysis has determined it to be infeasible at this time. Given the relatively flat, meandering nature of the Merced River and its associated floodplain through Yosemite Valley, it would be challenging to alter a bridge to allow natural river hydrology to occur without compromising the bridge’s historic integrity.

Bridges constructed in Yosemite Valley in the future would be designed to allow the hydrologic processes of the Merced River to function naturally, and would conform with the historic character of other bridges and structures in Yosemite Valley.

284. Public Concern: The Yosemite Valley Plan should require the restructuring of bridges in Yosemite Valley.

"Rather than eliminating the stone bridges, restructure them so that they will not obstruct or be otherwise detrimental to the river environment during the spring runoff." (Individual, Fresno, CA - #2962)

"I understand that many of the bridges now on the Merced River impede its flow during floods. This should not be allowed to continue. I see no necessary reason to keep the Sugar Pine Bridge, and the Ahwahnee Bridge and they should go. I think that bridges should be at all the other present bridge locations. However, those bridges, including Stoneman, should be rebuilt so that they do not impede flow of the Merced River at any time, particularly during flood conditions. The fact that the present bridges are historical is irrelevant. Mistakes should be corrected even if they are historical." (Individual, Modesto, CA - #3538)

Response: In order to be consistent with the 1980 General Management Plan goal of allowing natural processes to prevail, and of protecting the hydrologic process Outstandingly Remarkable Values of the Merced Wild and Scenic River, the National Park Service strives to allow the Merced River to meander, change course, and make other changes through uninterrupted hydrologic processes: erosion, deposition, winter flooding, spring runoff, large woody debris in the river channel, etc. Bridges and their abutments interrupt these hydrologic processes, particularly when the abutments are in the river channel and when they do not accommodate flood flows.

The National Park Service has investigated making modifications to the existing bridges in Yosemite Valley in order to lessen their impacts to hydrologic processes (Madej 1991, USDOT-FHA 1998). These potential modifications are short-term solutions, or do not adequately address impacts to hydrologic processes, or are such major modifications that they undermine the historic integrity of the bridge.

530. Public Concern: The Yosemite Valley Plan should assess the impacts of the historic bridges on the Merced River independently from other impacts.

"The National Trust does not dispute that the bridges have an impact on the Merced River, and that these impacts may be locally significant. We also recognize that the current Merced River ecosystem is severely stressed. We are convinced, however, that significant ecological restoration can take place without the removal of the historic bridges. We believe that the impacts of the historic bridges on the river ecosystem must be isolated from other impacts such as rip-rap and human tramping, and that these impacts be assessed objectively without predetermining bridge impacts to be by definition negative." (Non-Governmental Organization, San Francisco, CA - #7885)

Response: Milestone (1978) and Madej (1991) found that each of the 11 bridges across the Merced River in Yosemite Valley constrict the river to varying degrees, and that there were other human-caused alterations to the Merced River ecosystem (roads that act as dikes, hardened shorelines, loss of riparian vegetation, etc.). The principal adverse impacts of bridges to hydrologic processes are channel widening, channel scour, and mid-stream bar formation that occurs when a bridge does not accommodate flood flows and acts as a dam. These adverse impacts also result in loss of riparian vegetation.

One of the five goals of the General Management Plan is to "allow natural processes to prevail":

"The Yosemite environment is not a static accumulation of geologic and biologic features but rather a dynamic system of interrelated and evolving forms. Therefore, if this environment is to be preserved, the natural processes that are occurring there must be understood and allowed to prevail…"

The bridges, particularly Sugar Pine and Stoneman, are static objects that interfere with the "dynamic system" described in the General Management Plan.

Many restoration projects have removed riprap, restored riparian vegetation, and temporarily closed restored areas to visitor use. The bridges continue to create a significant adverse impact on water resources, hydrologic processes, and riparian vegetation, and the success of future restoration projects depends on their fate.

475. Public Concern: The Yosemite Valley Plan should include mitigation measures for the removal and construction of bridges in Yosemite Valley.

"The Service identifies no mitigation measures to protect the river during the removal or construction of bridges in the Valley. Although our organizations strongly support the removal of several Yosemite bridges, these impediments should not be removed until the NPS has a plan to protect the river flows and hydrologic processes to the maximum extent feasible." (Conservation Organization, San Francisco, CA - #4594)

"Two bridges would be added which would constrict the river. The natural meandering of the river would also be impacted by changes to the flood protection levee. Also proposed are additions to infrastructure at Railroad Flat. The Draft VP says these changes would minimize adverse impacts on hydrology and water quality, but completely lacks description as to how this would occur." (Conservation Organization, Yosemite, CA - #7883)

Response: To ensure that a high standard of protection of resources and values occurs, all potential future actions that could occur under each of the action alternatives proposed in the Final Yosemite Valley Plan/SEIS would apply a consistent set of measures to mitigate for potential environmental and social impacts. Mitigation measures relevant to the removal and construction of bridges in Yosemite Valley are included in Vol. IA, Chapter 2, Alternatives, Mitigation Measures Common to all Action Alternatives.

Examples of mitigation measures relevant to bridge removal or construction include: sustainable design; measures to reduce water pollution; measures to protect rare, threatened, and endangered species; scheduling of construction activities during periods of low groundwater; use of silt fences in construction areas to reduce erosion and surface scouring; revegetation plans for the disturbed area; employment of dust abatement measures; choosing bridge materials that are compatible with the landscape; and compliance with the Programmatic Agreement for cultural resources.

Sustainable design is particularly important for construction of new facilities, such as bridges. If a new bridge were constructed in Yosemite Valley it would be designed to accommodate flood flows and to the greatest degree possible allow the Merced River to meander and change course. New bridges in El Portal for the multi-use paved trail would be constructed and designed to accommodate flood flows, particularly flows of high velocity like those experienced in January 1997.

4.2.2 ~ Dams and Levees

Many respondents hold differing views on the subject of retaining levees in Yosemite Valley. One conservation organization questions how the proposed construction of levees, designed specifically to control and divert the Merced River’s flow, will be consistent with the General Management Plan’s intent to "let natural processes prevail." Conversely, another conservation group believes that the El Portal levee should be maintained. "The levee held its ground during the 1997 flood and, despite its rather unorthodox design, does not appear to have suffered permanent damage," the group suggests.

Numerous individuals wish to see the Cascades Diversion Dam removed in an environmentally responsible way, without any commensurate road widening projects linked to the dam’s removal. One individual, however, questions why the National Park Service would consider removing a dam without first analyzing the environmental consequences of such an action. "Removing or breaching the dam would allow the river to entrench the gravel deposit that had accumulated in the pool, sending a slug of sand and gravel downstream that would sediment pools throughout the gorge and eventually reduce (albeit very slightly) the storage capacity of Lake McClure, with attendant impacts on downstream agriculture and fisheries," this person asserts. The environmental consequences of this project should be analyzed, this person believes, before any decision is made.

533. Public Concern: The National Park Service should clarify how levee construction and water diversion are consistent with the direction of the General Management Plan.

"How is the proposed construction of ‘levees to divert water flow and remove areas from the 100-year floodplain,’ consistent with the declared intent to ‘let natural processes prevail?’ Construction of levees is--and historically has always been--for the purpose of preventing the consequences of natural processes." (Conservation Organization, Mariposa, CA - #9224)

Response: In order to remove facilities from Yosemite Valley as envisioned by the General Management Plan, it is necessary to develop new facilities in areas outside of Yosemite Valley. The Final Yosemite Valley Plan/SEIS proposes removing facilities that interfere with natural processes from Yosemite Valley (e.g., some bridges, campsites, roads), with particular importance placed on protecting the Merced River and restoring natural communities and processes in the River Protection Overlay. The Final Yosemite Valley Plan/SEIS presents a range of alternatives that include potential new facilities in El Portal, Foresta, and Wawona. Because of the intended purpose of the El Portal Administrative Site, many of these new facilities are proposed to be located in El Portal, and some of these facilities may have to be located in the floodplain and there may be a need for flood protection structures such as levees. Consistent with the legislation that established the El Portal Administrative Site, the General Management Plan intended El Portal to be the site of park headquarters and the base of many park operations.

Generally, in acknowledging the Merced Wild and Scenic River’s Outstandingly Remarkable Values, highly valued resources, and floodplain considerations (including Executive Order 11988, Floodplain Management, and the National Park Service Floodplain Management Guideline 1993), the action alternatives in the Final Yosemite Valley Plan/SEIS restrict new development or redevelopment within the floodplain, except where alternative locations are not feasible due to other resource constraints (e.g., rockfall hazard, sheer cliffs, cultural resources, threatened or endangered species, or scenic resources). Where no alternatives exist, and with a formal statement of findings (refer to Vol. II, Appendix N), policies allow construction of structures, such as day-visitor parking facilities, picnic areas, and campgrounds to be built within the floodplain if risks to human life and property are studied and then minimized or mitigated through design (e.g., construction of finished floors above the elevation of the 100-year floodplain, construction of levees to divert water flow and remove areas from the 100-year floodplain, and preparation of an emergency preparedness plan for facilities within the floodplain).

477. Public Concern: The Yosemite Valley Plan should require the retention of the levee in El Portal.

"We support the following proposition--retention of the existing levee. The levee held its ground during the 1997 flood and, despite its rather unorthodox design, does not appear to have suffered permanent damage. If later examinations of the levee in fact suggest that repairs are needed, we urge the Park Service to permit (and the YVP to specify) only the least amount of necessary work. The last thing the public wishes to view on Highway 140 (and hopefully the last thing the Park Service wishes to take upon itself) is a massive scarring and excavation of the Merced River watershed." (Conservation Organization, San Francisco, CA - #4594)

Response: The Preferred Alternative in the Final Yosemite Valley Plan/SEIS proposes to increase the height and length of the flood protection levee in El Portal to protect housing units at Hennessey’s Ranch, and anticipates the continued existence of the levee along State Route 140 in the vicinity of the El Portal Market and the El Portal Ranger Office. A flood wall may also be necessary at Railroad Flat. These actions would need to be consistent with the applicable management zoning, the River Protection Overlay, and the Wild and Scenic Rivers Act (WSRA) as described in the Merced River Plan/FEIS, as well as Executive Order 11988 on Floodplain Management, and the National Park Service Floodplain Management Guideline (1993).

Under the Wild and Scenic Rivers Act, the National Park Service is charged with maintaining whenever possible the free-flowing nature of the Merced River as it runs through Yosemite National Park. Section 7 of the Act (16 USC 1277) requires a rigorous process to ensure that proposed "water resources projects," implemented or assisted by federal agencies within the bed and banks of designated rivers, do not have a "direct and adverse effect" on the values for which the river was designated. "Water resources projects" include hydroelectric projects, dam or water diversions, fisheries habitat and watershed restoration, bridges and other roadway construction or reconstruction, bank stabilization, channelization, levees, boat ramps, and fishing piers that occur within the bed and banks of a designated Wild and Scenic River (Interagency Wild and Scenic Rivers Coordinating Council 1999).

275. Public Concern: The Yosemite Valley Plan should require the removal of the Cascade Diversion Dam and riprap along the Merced River.

"Remove Cascade Dam and the riprap along the River." (Public Hearing, Merced, CA - #20101)

Response: Each of the action Alternatives in the Final Yosemite Valley Plan/SEIS propose the removal of the Cascade Diversion Dam. However, further environmental compliance would be necessary before the dam could be removed. In addition, the document calls for the reconstruction of El Portal Road between the dam and Pohono Bridge, which would also require further environmental compliance and could be affected by the removal of the dam. Environmental compliance typically includes mitigation measures to reduce or eliminate adverse impacts. Under the permit issued to the National Park Service by the U.S. Army Corp of Engineers, bank restoration is also required in the area of the dam removal.

Riverbank restoration projects under all action alternatives of the Final Yosemite Valley Plan/SEIS, would include, where feasible, the removal of riprap and other unnatural slope protection along reaches of the Merced River in Yosemite Valley. However, riprap or rock armor is necessary in some cases to protect the riverbank and maintain structural integrity of roads, bridges, or other structures.

The El Portal Administrative Site was established by Congress in 1958 (P.L. 85-922) "in order that utilities, facilities, and services required in the operation and administration of Yosemite National Park may be located on such site outside the park." The act also stated that the site would "not become part of Yosemite National Park, nor be subject to the same laws and regulations governing said park." Accordingly, constraints on development in the 100-year floodplain and the use of riprap in El Portal are different from constraints inside the park.

In both Yosemite Valley and El Portal, the provisions of the Merced River Plan/FEIS would guide and constrain actions potentially affecting the Merced River.

(Also see response to Concerns #533 and #3.)

239. Public Concern: The Yosemite Valley Plan should require environmentally responsible techniques for the removal of Cascades Diversion Dam.

"Be environmentally responsible with the removal of Cascades Dam." (Individual, San Francisco, CA - #1212)

Response: While the Final Yosemite Valley Plan/SEIS calls for the removal of the Cascades Diversion Dam, further environmental compliance would be necessary before the dam could be removed. In addition, the plan calls for the reconstruction of El Portal Road between the dam and Pohono Bridge, which would require further environmental compliance and could be affected by the removal of the dam. Environmental compliance typically includes mitigation to reduce or eliminate adverse impacts associated with an action.

The National Park Service has studied the removal of the dam, including different removal techniques and different methods of treatment for the sediment that has accumulated behind the dam. For further information see NPS Environmental Assessment for Electrical Distribution System Replacement and Cascade Dam Removal (1987), and USGS Assessment of Hydraulic Changes Associated with Removal of Cascade Dam (1989).

The U.S. Army Corps of Engineers granted the National Park Service a permit to remove Cascades Diversion Dam in June 1998. Under this permit, the National Park Service is required to comply with all the applicable provisions and special conditions to ensure protection of the environment, including erosion and siltation controls, aquatic life movements, and endangered species. In addition, the National Park Service would comply with the requirements of the Wild and Scenic Rivers Act, including the Section 7 determination process.

240. Public Concern: The Yosemite Valley Plan should not link dam removal to road widening.

ﾒDon’t link the [Cascades] dam removal to more road widening." (Individual, San Francisco, CA - #1212)

Response: The removal of the Cascades Diversion Dam does not depend on the widening of the El Portal Road or the Big Oak Flat/El Portal Road intersection improvements and is consistent with the goals of the Merced River Plan/FEIS. On the other hand, the road and intersection improvements are partially dependent on the removal of the dam, the subsequent response of the river, and may require further environmental compliance. Thus, it is likely that these two projects would be implemented in two phases. The first phase would entail removing the dam and allowing the river to flow unimpeded for a period sufficient for the channel to stabilize and to assess its eventual course. After that period of assessment, phase two, road widening and intersection improvement, would be evaluated.

346. Public Concern: The National Park Service should analyze the environmental impacts of removing the diversion dam.

"Though low, the diversion dam does impound a scenic pool; replacing that pool with an eroded gravel terrace would be visually and environmentally destructive. Removing or breaching the dam would allow the river to entrench the gravel deposit that had accumulated in the pool, sending a slug of sand and gravel downstream that would sediment pools throughout the gorge and eventually reduce (albeit very slightly) the storage capacity of Lake McClure, with attendant impacts on downstream agriculture and fisheries. That removal reappears in alternative after alternative with no analysis of these impacts or their mitigation suggests a triumph of dogmatism over analysis that is altogether inappropriate in an EIS." (Individual, Oakland, CA - #3835)

Response: While the Final Yosemite Valley Plan/SEIS calls for the removal of the Cascades Diversion Dam, further environmental compliance would be necessary before the dam could be removed. Environmental compliance typically includes mitigation measures to reduce or eliminate adverse impacts associated with an action, such as the treatment of accumulated sediment in the pool upstream of the dam. The National Park Service has studied the removal of the dam, including different removal techniques and different methods of sediment treatment. For further information see NPS Environmental Assessment for Electrical Distribution System Replacement and Cascade Dam Removal (1987), and USGS Assessment of Hydraulic Changes Associated with Removal of Cascade Dam (1989).

4.2.3 ~ Floodplains

Floodplains and the development contained within them are topics of concern for many Draft Yosemite Valley Plan/SEIS respondents. Several respondents seek clarification of the seemingly contradictory mandates in the Draft Yosemite Valley Plan/SEIS regarding floodplains. "Mention was made of the importance of pulling back buildings from the floodplain," states one individual. "Why then are you planning to replace the buildings at Yosemite Lodge that were lost to the flood?" Another person remarks, "You list all of the facilities located within the floodplain of the Merced, but offer no explanation whatsoever on how you determined what would be kept, what would be rebuilt and what would be removed." Conversely, one respondent feels that floodplains and development are not mutually exclusive. Citing the example of the Rhine and Main Rivers in Germany, this person points out that these rivers are expected to inundate their floodplains each spring. "The playground and picnic equipment are removed," this person ventures. "The trails are closed and in the late spring fresh sand is put in the sand boxes. How can you justify not using the flood plain?" Such a strategy could be implemented to continue using Housekeeping Camp at its present capacity, according to this individual.

While some respondents believe that the National Park Service should remove all facilities located within the 100-year floodplain of the Merced River, others question the adequacy of analysis regarding floodplain development. "I find it extremely disheartening that you did not include an alternative that considered the removal of all facilities from the floodplain. Being that the MRP dictates how YVP will be implemented, I question the adequacy of analysis done on floodplain development," comments one citizen. Another individual believes that the Final Yosemite Valley Plan/SEIS should contain detailed maps of the Merced River’s 100-year floodplain. Such a map would assist in the location and protection of Merced River Outstandingly Remarkable Values, according to this respondent.

The past and planned reconstruction of the El Portal Road and its impact on the Merced River watershed elicits many comments. The National Park Service should devise mitigation measures for the major adverse hydrologic and scenic impacts created by reconstruction of the El Portal Road, according to one conservation organization. This group believes, "By creating and articulating greater mitigation measures in the final plan, the park service can forestall some of the public and controversial visual and ecological impacts that typically accompany road construction along the Merced." Yet another conservation group suggests that the Final Yosemite Valley Plan/SEIS account for cumulative impacts on the El Portal segment of the Merced River Canyon. Noting past construction in the El Portal canyon, this organization chides, "No valid measurement of cumulative impacts is provided, and it is as though nothing ever happened in the Merced Gorge and that no land area, hydrology, wildlife, or plants were ever disturbed." A cumulative impacts analysis, this group insists, should be included in the Final Yosemite Valley Plan/SEIS.

181. Public Concern: The National Park Service should clarify the Yosemite Valley Plan’s management direction regarding floodplain development.

"Mention was made of the importance of pulling back buildings from the floodplain. Why then are you planning to replace the buildings at Yosemite Lodge that were lost to the flood?" (Individual, Walnut Creek, CA - #84)

"You list all of the facilities located within the floodplain of the Merced, but offer no explanation whatsoever on how you determined what would be kept, what would be rebuilt and what would be removed. Volume 1A states, ‘These structures or developed areas may be inconsistent with the NPS Floodplain Management Guidelines or Executive Order 11988 because these administrative requirements were imposed after the facilities were constructed.’ Are you trying to say that you aren’t going to move these facilities out of the floodplain because you legally don’t have to? You and I both know that to restore the Merced River to a truly natural system, man-made impediments need to be removed from the river’s natural path. I find it extremely disheartening that you did not include an alternative that considered the removal of all facilities from the floodplain. Being that the MRP dictates how YVP will be implemented, I question the adequacy of analysis done on floodplain development." (Individual, Missoula, MT - #7257)

"What about Housekeeping Camp? A rich tradition for my family and many others. The concrete and stone uprights are waterproof. The stoves, beds, pantries and canvas can be removed by Nov.1. We lived in Germany in 1995-97 where the Rhine and Main rivers are expected to rise 3-4 meters above their banks every spring. The playground and picnic equipment are removed. The trails are closed and in the late spring fresh sand is put in the sand boxes. How can you justify not using the flood plain?" (Individual, Jackson, CA - #1494)

Response: Yosemite National Park currently operates under Executive Order 11988, Floodplain Management, and the National Park Service Floodplain Management Guideline (1993), which provide guidance for the minimization of hazard to life and property and protection of natural floodplain values in the national park system. One of the goals of the 1980 General Management Plan is to allow natural processes, such as flooding, to prevail in the park. In addition, an active flood regime is a component of the hydrologic process Outstandingly Remarkable Value of the Merced Wild and Scenic River in Yosemite Valley. Both the General Management Plan and the Merced River Plan envision the natural hydrologic process of flooding to be unimpaired by human activities, including structures. The Yosemite Valley Plan would implement this vision by removing as many structures as is feasible from the 100-year floodplain.

Also, in accordance with the Executive Order, National Park Service guidelines, the General Management Plan, and the Merced River Plan, the Final Yosemite Valley Plan/SEIS proposes the removal of a number of facilities from the 100-year floodplain of the Merced River in Yosemite Valley to reduce hazards to life and property and to restore floodplain values. Existing facilities within the floodplain could be flood-proofed to reduce hazard to life and property, but the adverse impacts of the structures to floodplain values would continue. New facilities could be constructed in the floodplain if it were not feasible to locate the facility elsewhere; these facilities would be subject to standard mitigations of facilities in floodplains. For example, lodging units would be removed from the 100-year floodplain at Yosemite Lodge, and any new lodging units at Yosemite Lodge would be constructed outside of the 100-year floodplain.

In the Final Yosemite Valley Plan/SEIS, facilities in Yosemite Valley, El Portal, and Wawona that are within the 100-year floodplain of the Merced River are listed in the Floodplains section of Vol. IA, Chapter 3, Affected Environment. Vol. IB, Chapter 4, Environmental Consequences, discusses the impacts of facilities in the floodplain. A floodplain hazard assessment, known as a Statement of Findings, has been prepared by the National Park Service Water Resources Division and is included in Vol. II, Appendix N.

Please note that in Vol. IA, Chapter 2 the Preferred Alternative does not propose the rebuilding of any portion of Yosemite Lodge in the 100-year floodplain.

252. Public Concern: The Yosemite Valley Plan should remove all facilities in the 100-year floodplain.

"Remove all facilities in the 100-year floodplain." (Public Hearing, Merced, CA - #20101)

Response: Consistent with Executive Order 11988, Floodplain Management, the National Park Service Floodplain Management Guideline (1993), the 1980 General Management Plan goal of allowing natural processes to prevail, and the Merced River Plan goal to protect and enhance the hydrologic process Outstandingly Remarkable Value for the Yosemite Valley segment, the Final Yosemite Valley Plan/SEIS proposes the removal of a number of facilities from the 100-year floodplain of the Merced River in Yosemite Valley and limits new development or redevelopment.

These policies and plans allow development in the floodplain where alternative locations are not feasible due to other constraints (e.g., rockfall hazard, sheer cliffs, cultural resources, threatened or endangered species, scenic resources). Examples of development that can be placed in the floodplain include day-visitor parking areas, picnic areas, and campgrounds. When development in the floodplain is proposed, risks to human life and property must be minimized or mitigated through design (e.g., construction of finished floors above the elevation of the 100-year floodplain, construction of levees to divert water flow and remove areas from the 100-year floodplain, preparation of an emergency preparedness plan for facilities within the floodplain), and a Statement of Findings must be prepared.

The El Portal Administrative Site was established by Congress in 1958 (P.L. 85-922) "in order that utilities, facilities, and services required in the operation and administration of Yosemite National Park may be located on such site outside the park." The act also stated that the site would "not become part of Yosemite National Park, nor be subject to the same laws and regulations governing said park." Accordingly, floodplain development constraints in El Portal are different from constraints inside the park; however, risks to human life and property must still be minimized or mitigated.

In both Yosemite Valley and El Portal, the provisions of the Merced River Plan/FEIS would guide and constrain actions potentially affecting the Merced River.
(Also see response to Concerns #533 and #3.)

551. Public Concern: The National Park Service should accurately map the Merced River’s 100-year floodplain.

"NPS has failed to map and consider the Merced’s 100-year flood limits, channel morphology and migration, associated wetlands, and Terminal Moraine restoration. NPS has failed to map ‘normal bankfull high water’ (which in Yosemite is the Spring Flood, covering many acres of meadow). The 100-year floodplain has never been mapped. These kinds of maps would hold many keys to proposing specific, located protections for the Merced River and provide dimensions upon which to build further detailed, located study and specific protection of the Merced’s ORV’s." (Conservation Organization, Yosemite, CA - #7883)

Response: In 1981, the U.S. Army Corps of Engineers delineated the predicted 100-year floodplain of the Merced River in Yosemite Valley, and revised their prediction in 1991. In January 1997, the National Park Service mapped the flood extent levels in Yosemite Valley following the largest flood event since the installation of the stream gauge at Happy Isles in 1916. The January 1997 flood revealed serious flaws in the U.S. Army Corps of Engineers prediction: some areas that were supposed to flood did not flood, and some areas flooded that were not supposed to flood, according to the U.S. Army Corps of Engineers data. The National Park Service believes that the 1997 flood extent data is a more accurate representation of the 100-year floodplain than the U.S. Army Corps of Engineers prediction.

In 1998 and 2000, Stantec Inc. (formerly Cella Barr and Associates) mapped the predicted 100-year, 25-year, 10-year, and 2-year floodplain in east Yosemite Valley from Happy Isles to Swinging Bridge using an updated hydrologic model incorporating the 1997 flood data and updated topographic information (Stantec 2000; Cella Barr and Associates 1998). The 1998 and 2000 predicted flood extents in east Yosemite Valley from Stantec data, combined with the mapped 1997 flood extent in west Yosemite Valley, is considered the most accurate available 100-year floodplain prediction for this section of the Merced River corridor.

In El Portal, the predicted 100-year floodplain was delineated by the U.S. Army Corps of Engineers in 1991, and was revised following the January 1997 flood.

The predicted floodplain extent in Yosemite Valley and El Portal provided guidance during the alternative development process (see Vol. IA, Chapter 2, Development Considerations) and was used to evaluate environmental consequences for water resources (see Vol. IB, Chapter 4, Environmental Consequences, Floodplains) in both the Draft and Final Yosemite Valley Plan/SEIS. In addition, the Final Yosemite Valley Plan/SEIS includes an appendix with a Floodplain Statement of Findings (see Vol. II, Appendix N) for the Merced River in Yosemite Valley and El Portal. The Statement of Findings identifies the potential hazards and risks associated with development within the 100-year floodplain and evaluates the feasibility of removing or retaining facilities within these areas.

611. Public Concern: The Yosemite Valley Plan should include mitigation measures for the adverse hydrologic and scenic impacts created by the reconstruction of the El Portal Road.

"The NPS must devise mitigation measures for the major adverse hydrologic and scenic impacts created by reconstruction of El Portal Road between Cascades Diversion Dam and the Pohono Bridge. The draft YVP identifies no mitigation for the visual impacts created by the presence of construction activities, and little mitigation for the hydrologic damage created by the presence of bank stabilization materials. By creating and articulating greater mitigation measures in the final plan, the Park Service can forestall some of the public and controversial visual and ecological impacts that typically accompany road construction along the Merced." (Conservation Organization, San Francisco, CA - #4594)

Response: A list of mitigation measures common to all action alternatives can be found in the Final Yosemite Valley Plan/SEIS, Vol. IA, Chapter 2, Alternatives. Mitigation measures associated with road construction projects include sustainable design and aesthetics that minimize impacts to hydrology and scenery, revegetation, construction practices that minimize impacts to resources and visitors, etc.

The reconstruction of the El Portal Road between Cascades Diversion Dam and Pohono Bridge would be preceded by the removal of the Cascades Diversion Dam. The final design for this segment of road is partially dependent on the removal of the dam and the response of the river to the removal of the dam; therefore, the design for this segment of road has not been finalized. Subsequent environmental compliance would be necessary before the reconstruction of this segment can proceed, and specific mitigation measures would be a component of this compliance.

Pursuant to the Wild and Scenic Rivers Act and the Merced River Plan/FEIS, this project would be considered a water resources project and would be subject to a Wild and Scenic Rivers Act Section 7 determination. This would strive to avoid direct and adverse impacts to Outstanding Remarkable Values, particularly the hydrologic processes and scenic Outstanding Remarkable Values of this segment.

539. Public Concern: The Yosemite Valley Plan should account for cumulative impacts on the El Portal segment of the Merced River Canyon.

"El Portal is a segment of Canyon and riparian zones which are the most threatened in the Sierra (Sierra Nevada Ecoregion Project). Yet, no valid measurement of cumulative impacts is provided, and it is as though nothing ever happened in the Merced Gorge and that no land area, hydrology, wildlife, or plants were ever disturbed." (Conservation Organization, Yosemite, CA - #7883)

Response: Reconstruction of the El Portal Road between the park boundary at El Portal and the Cascades Diversion Dam is currently underway, and therefore is outside the scope of this planning effort. However, it is analyzed in the Final Yosemite Valley Plan/SEIS as a "present" cumulative impact project (see Vol. IB, Chapter 4, Environmental Consequences, Cumulative Impacts section of each impact topic). Mitigation measures for this construction project are being implemented as the project nears completion. Examples of measures being employed include weed control at staging areas and throughout the project site, construction compliance monitoring, revegetation, fencing of sensitive resource areas, and long-term monitoring.

4.2.4 ~ Hydrology and Geology

Several respondents feel that past human actions in Yosemite Valley have altered the natural hydrogeomorphic processes of the Merced River. To restore hydrologic and geologic balance, many suggest that the National Park Service restore the El Capitan moraine. "Partially restoring the terminal moraine would surely extend the wetting and flooding of meadows from El Capitan through Leidig, and possibly as far as Ahwahnee," one respondent maintains.

Offering a different restorative measure, another respondent believes raising the Merced River bed will lead to increased inundation of the meadows and a commensurate retreat of the encroaching woodlands. This person suggests a novel source of materials for this proposed mitigation project: "Some of the boulders from the dismantled Stoneman and other bridges proposed for removal might be useful." Although this project alone may not ensure the restoration of the meadows, this individual feels that "the prospect of raising the water table a few feet should encourage you to at least discuss the costs and probable advantages in the FEIS."

Note: One response is provided for concerns #347 and #467, and is placed following concern #467.

347. Public Concern: The National Park Service should consider restoring the El Capitan terminal moraine.

"The lowered water table near El Capitan is among the most prominent of the historical changes to Yosemite Valley. Partially restoring the terminal moraine would surely extend the wetting and flooding of meadows from El Capitan through Leidig, and possibly as far as Ahwahnee. A higher water table, together with annosus fungus will eventually expand some of the floodplain meadows and open-up nearby woodlands. To go much beyond this towards recreating the more expansive grasslands of 1866 would neither be more natural (because the pre-historic burn frequency appears to have been anthropogenic), nor be more attractive. I recommend shallowing Clark’s deep and narrow channel through the moraine by only two or three feet, then waiting decades before deciding whether to add more. Several large rocks may be required, as Clark’s deep channel appears to have been swept clear of mere boulders." (Individual, Oakland, CA - #3835)

Response: See response following concern #467 below.

467. Public Concern: The National Park Service should consider raising the Merced River bed.

"Bed stability is an argument for raising the bed rather than accepting it as it now is. In the NPS technical Report 92/10 by Smillie, Jackson and Martin in May 1992, they present reasons for raising the river bed, although they are not sure that that alone will entirely push back the trees encroaching on the meadow. A stable bed and the prospect of raising the water table a few feet should encourage you to at least discuss the costs and probable advantages in the FEIS. A stable river bed tells me that if a wide thick foundation could be placed with confidence it will stay put. Perhaps large boulders might be through-bolted to that foundation to provide a mostly natural looking barrier of perhaps 4.5 feet height as a first step as they suggest. Some of the boulders from the dismantled Stoneman and other bridges proposed for removal might be useful." (Individual, Twain Harte, CA - #7633)

Response: One of the goals of the 1980 General Management Plan is to "allow natural processes to prevail." When natural processes have been impaired by human influences and are not functioning properly, the National Park Service intervenes to restore the natural processes and mimic their influence, as well as restore the resources that have been damaged or lost due to the interruption of natural processes. As an example, the altered water regime in meadows has resulted in the encroachment of conifers into the meadows, and the National Park Service regularly burns the meadows in order to control the encroachment. However, restoration programs that mimic the influence of a natural process are imperfect, and care must be taken to avoid impacts to other natural processes or natural and cultural resources.

Constructing terraces in the Merced River east of the terminal moraine would impede river flow and not allow natural river processes to prevail. In addition, constructing terraces in the Merced River to impede river flow would not comply with the guidance and direction provided in the Merced River Plan/FEIS associated with not impeding natural river flow.

This response also applies to concern #347.

4.2.5 ~ Impacts, Mitigation, and Restoration

Bridges, dams, levees, and roads manifestly impact water resources and are often mentioned in the public’s comments. Citizens also ask that a variety of possible water contaminants be considered including non-point source pollutants, storm water runoff, and stock effluent.

An increase of in the human population of El Portal, one respondent remarks, could lead to increased non-point source pollutants including pollution derived from "parking lots, residential and working facilities, and vehicle deposits on road beds." Such pollutants, "may adversely affect populations of aquatic insects, especially those that are sensitive to pollution, which may adversely affect bat, bird and fish populations," this individual attests. The Final Yosemite Valley Plan/SEIS should consider the cumulative impacts such a population increase may have on water resources, according to this citizen.

Another individual believes that the Final Yosemite Valley Plan/SEIS should include storm water mitigation measures, such as the use of vegetated swales. "This is common practice and could easily be incorporated in the Yosemite Valley Plan," states this person.

One equestrian respondent questions the draft plan’s assertion that the present location of the rental stable impacts riparian areas and water quality. This person writes that such an assertion "should be supported by tests run by environmental biologists. Where are the test results?" Including this information in the Final Yosemite Valley Plan/SEIS would improve the document, according to this individual.

Finally, one person requests the restoration of Mirror Lake. "Restore Mirror Lake by removing the blockages" is this respondent’s brief request. The nature or size of the "blockages" is not elucidated in the citizen’s letter.

542. Public Concern: The Yosemite Valley Plan should consider the cumulative impacts of non-point source pollution from an increased human population in El Portal.

"The DVP does not consider the related and cumulative impacts of increasing human population in El Portal, leading to non-point pollution from parking lots, residential and working facilities, and vehicle deposits on road beds. This may adversely affect populations of aquatic insects, especially those that are sensitive to pollution, which may adversely affect bat, bird and fish populations." (Conservation Organization, Yosemite, CA - #7883)

Response: Increased development in El Portal could carry the increased risk of non-point source pollution. The Preferred Alternative in the Final Yosemite Valley Plan/SEIS, however, provides specific actions and mitigation measures that would limit such risk to a negligible level. Development within 150 feet of the river would be limited by the River Protection Overlay. Runoff from parking lots, roadways, and residential and working areas would be collected for treatment. Effluent from all new facilities in El Portal would be piped into the existing sewage treatment system. Facilities that carry an inherent risk of causing pollution (e.g., fueling facilities) would be designed to strictly limit the chance of spills, and provide adequate containment and treatment of potential spills. The largest benefit to water quality in El Portal under the Final Yosemite Valley Plan/SEIS action alternatives would be the removal of the commercial bulk fuel facility. This facility poses the greatest risk of both catastrophic spills and continual, low-level pollution from runoff into the river and adjacent wetlands, and seepage into groundwater.

In a cumulative context, the development in El Portal would also represent a net gain in protecting water quality and the organisms sensitive to any degradation of water quality. Under existing conditions, many facilities in Yosemite Valley remain in the floodplain, where inundation could cause substantial releases of pollutants. Parking areas in the Valley currently have largely uncontrolled runoff, and many roadways run through meadows where petroleum-tainted runoff can affect aquatic habitats, and spills could have a devastating effect. Under the Preferred Alternative in the Final Yosemite Valley Plan/SEIS, many of these threats would be reduced. The number of cars parking in Yosemite Valley would be reduced, and parking lots that would remain in the Valley, or would be established outside the Valley, would have strict standards for containment and treatment of water pollutants. Relocation of housing and work areas out of the floodplain and out of Yosemite Valley, where they could also be constructed to higher standards, would further reduce threats to water quality in the Merced River. Restoration of aquatic and riparian habitats would provide direct benefits to a wide range of organisms dependent upon these habitats.

631. Public Concern: The Yosemite Valley Plan should provide for storm water mitigation measures.

"The SEIS fails to consider the use of vegetated swales and similar storm water mitigation measures to reduce the impacts of non-point pollution sources such as parking lots. This is common practice and could easily be incorporated in the Yosemite Valley Plan." (Individual, Union City, CA - #4404)

Response: A mitigation measure common to all of the Final Yosemite Valley Plan/SEIS action alternatives is the "integration of stormwater pollution controls into design, construction, and operation of new facilities, parking areas, and other paved surfaces that concentrate runoff." Parking at Yosemite Village would include such stormwater pollution controls. The River Protection Overlay also protects water quality by limiting development in the areas immediately adjacent to the Merced River and providing a "filter" between developed areas and the river.

(Also see response to Concern #757.)

606. Public Concern: The Yosemite Valley Plan should substantiate claims that the horse stables negatively impact riparian areas and water quality.

"Statements that the present location of rental stables impacts riparian areas and water quality of runoff should be supported by tests run by environmental biologists. Where are the test results?" (Individual, No Address - #3492)

Response: It is the goal of the Yosemite Valley Plan to preserve the natural processes and cultural heritage of Yosemite Valley while providing a wide range of high quality visitor experiences and opportunities. The long tradition of stock use and its importance to some users is recognized and much consideration has been given to providing opportunities for stock use. Conversely, other visitors have voiced concerns about conflicts with stock on trails and the effects of the presence of stock on the quality of their experience and on natural resources.

The current concessioner stable operation sits directly adjacent to Tenaya Creek, just upstream of its confluence with the Merced River. Lands immediately upstream and downstream of the stable have been identified as wetlands in site-specific surveys. Soils in these areas consist of hydric black sandy loam soils. Small pockets of vegetative cover are characterized by facultative wetland species, including white alder, and obligate wetlands species such as rushes and sedges. These characteristics, in conjunction with known flood frequencies through the stable area, indicate that the stable is situated on a site that could (and historically did) support riparian vegetation. Most of the stable area is denuded of vegetation, indicating a loss or impact to riparian communities (see Final Yosemite Valley Plan/SEIS, Vol. IA, Chapter 3, Affected Environment).

The stable also supports a large seasonal population of brown-headed cowbirds that frequent the site because of the high concentration of horse manure that supports the insects on which the cowbirds feed. Various wildlife studies indicate that impacts from nest parasitism by brown-headed cowbirds on bird species that nest in riparian habitats can have severe effects on these species (see Chapter 3, Affected Environment).

The geographic location of the stable directly adjacent to Tenaya Creek and only a few feet above it vertically means this site receives fairly frequent flooding, as well as frequent groundwater inundation of portions of the site during spring runoff. All fecal and urinary wastes on the ground and in the soils are flushed away through either sheetflow or near-surface water flows, carrying these wastes directly into the river system. Because of the lack of wetland and riparian vegetation between the stable and the river's edge, there is little or no ability for nutrient uptake to minimize these discharges into the river.

Such impacts to the riparian environment (soils, water, and vegetation), the highly valued resources, and the natural river processes support the proposed action to remove the stable from its current location.

610. Public Concern: The Yosemite Valley Plan should require the restoration of Mirror Lake.

"Restore Mirror Lake by removing the blockages." (Individual, Reseda, CA - #4221)

Response: Mirror Lake has been manipulated in the past by sand dredging and construction of a rubble dam. Consistent with the 1980 General Management Plan goal to "allow natural processes to prevail," Mirror Lake is no longer manipulated and the National Park Service has largely restored its natural fluvial processes. Further restoration at Mirror Lake is beyond the scope of the Yosemite Valley Plan.

757. Public Concern: The National Park Service should develop site designs for out-of-Valley parking that protect storm water quality.

"Alternatives 2,4, and 5 all include out-of-Valley parking. The SEIS identifies the number of parking spaces needed at each of the sites, but does not provide information on the size of the out-of-Valley parking sites or any specific site design features under consideration for these sites. EPA is concerned that the creation of conventional, impermeable "black-top" parking surfaces can lead to the concentration of polluted storm water runoff." (Environmental Protection Agency, San Francisco, CA - #10295)

Response: Vol. IB, Chapter 4, Environmental Consequences, of the Final Yosemite Valley Plan/SEIS identifies the size (in acres) of each of the out-of-Valley parking facilities and discusses the associated impacts of this development. Specific site design features for the parking facilities are outside of the scope of the Yosemite Valley Plan; however, mitigation measures related to impacts from parking facilities are identified in Vol. IA, Chapter 2, Alternatives. These measures include:

Integrate storm water pollution controls into design, construction, and operation of new facilities, parking areas, and other paved surfaces that concentrate runoff.
Impacts on the site’s resources will be minimized and mitigated. The design for the impermeable areas and the associated runoff subsequent to hydrologic events would provide for appropriate drainage to ensure that natural resources are not further degraded.
Define parking area boundaries to confine damage from vehicles and trampling of meadows and other sensitive resource areas.
Design of parking would allow minimal resistance for flood waters, therefore minimizing impacts on the river, the road, and associated parking.

Section 4.3 ~ Wetlands

Protecting the natural resources of Yosemite Valley, including the Merced River and its associated wetlands and riparian areas, is an important priority for some Draft Yosemite Valley Plan/SEIS respondents. Of those respondents expressing concern over the future of the Valley’s wetlands, one individual additionally requests that the Yosemite Valley planning team be more consistent and accurate with the definitions used to describe wetlands and riparian areas. Noting that the terms riparian and wetland are distinct concepts, this individual exhorts the National Park Service to use the Fish and Wildlife Service’s definitions for riparian areas and wetlands. "Please stop interchanging riparian with wetland," requests this person. "It is patently false and extremely misleading to both those who understand the distinction and those that don’t."

This section concludes with technical and editorial comments regarding wetland nomenclature used in Table 3.1 and throughout the text of the Draft Yosemite Valley Plan/SEIS. One technical comment included in this section questions whether actual dynamite was used to blast the El Capitan moraine in 1879. This reader suggests that less effective explosives were used, hence reducing the actual impact the event had on the Merced River’s hydrology and the adjacent water table.

3. Public Concern: The Yosemite Valley Plan should emphasize the protection of the Merced River corridor.

"By all means do protect the river and river corridor. I hope my grandchildren will one day see a true riparian forest in the Valley." (Individual, Penngrove, CA - #95)

Response: The Yosemite Valley Plan emphasizes the protection of the Merced River corridor, particularly in Yosemite Valley. Allowing natural processes to prevail is a primary goal of the 1980 General Management Plan and has been an important factor in the development of the Yosemite Valley Plan/SEIS (see Vol. IA, Chapter 1, Purpose and Need). It is recognized that natural processes play a major role in maintaining a healthy ecosystem and the Valley’s scenic beauty. Primary among these are the hydrologic processes. The Merced River and its tributaries provide a mosaic of habitats, including meadows, wetlands, and woodlands, that support wildlife and biological diversity. The Preferred Alternative would seek to restore substantially altered natural systems and protect unaltered systems.

The Yosemite Valley Plan/SEIS is consistent with the Merced Wild and Scenic River Comprehensive Management Plan (Merced River Plan/FEIS). In 1987 Congress designated the Merced Wild and Scenic River, which is administered in separate segments by the National Park Service, the U.S. Forest Service, and the Bureau of Land Management. In 1999 and 2000, the National Park Service developed the Merced River Plan/FEIS for the sections of the Merced Wild and Scenic River that it administers. Included in the plan are descriptions of the seven management elements, including boundaries, the official classifications of river segments, the Outstandingly Remarkable Values (ORVs, such as hydrologic processes) associated with the Merced River, the Wild and Scenic Rivers Act Section 7 determination process, the River Protection Overlay, management zones and prescriptions, and the Visitor Experience and Resource Protection framework. Primarily a land-use zoning plan, the purpose of the Merced River Plan/FEIS is to protect and enhance the river’s Outstandingly Remarkable Values for the benefit and enjoyment of present and future generations. The plan’s management zone prescriptions and River Protection Overlay guide the Yosemite Valley Plan in the type of development and levels of use allowed within the Merced River corridor in Yosemite Valley, Wawona, and El Portal. Consistent with the Merced River Plan/FEIS, the intent of the Yosemite Valley Plan /SEIS is to protect and enhance the Merced River’s Outstandingly Remarkable Values.

An important tool to protect the areas immediately adjacent to the river is the River Protection Overlay, which was established in the Merced River Plan and would be implemented in the Yosemite Valley Plan. This prescription encourages restoration in a buffer area adjacent to and within the river, and limits development to essential facilities.

The Merced Wild and Scenic River is described in Vol. Ia, Chapter 3, Affected Environment. Impacts to the Merced Wild and Scenic River are described in Vol. Ib, Chapter 4, Environmental Consequences. Graphics portraying the Merced Wild and Scenic River and the boundaries are found in Vol. Ic, Plates. The Merced Wild and Scenic River classifications, Outstandingly Remarkable Values, Management Zones, and River Protection Overlay are described in Vol. II, Appendices.

493. Public Concern: The National Park Service should clarify the definition for "wetlands" in the Yosemite Valley Plan.

"You provide the classic F&WS Cowardin definition for wetlands in chapter 3 of Volume IA, but on page 2-8 of that same volume you provide this different, and extremely inaccurate, definition: ‘Wetlands: Wetlands are integral to the Merced River ecosystem and are usually found adjacent to (emphasis added) the river and its tributaries. Wetland communities include the river channel, riparian, and meadow communities. Wetlands are among the most biologically diverse natural communities. Riparian wetlands, (emphasis added) in particular, are some of the most productive of any natural community.’ The problems with this definition are myriad. (1). Wetlands and Riparian Areas are distinct ecological classifications, yet you create a new ecotone by coining the phrase ‘Riparian wetlands.’ (2). Wetlands are ‘usually found adjacent to the river’ but then the definition goes on to contradict this ‘wetland communities include the river channel . . .’ According to Hansen, ‘Permanent waters of streams and water deeper than 3m in lakes and reservoirs are not considered wetlands.’ (Hansen, et al 1995) Ergo, any stream or river shallower than 3m is a wetland in its entirety. (3). ‘Adjacent to the river’ is the phrase most likely to show up in your definition of riparian, which again, is a distinct ecological community from a wetland community (which, again, you use interchangeably in the second sentence of this definition). The National Park Service should exclusively use the Cowardin definition for wetlands to avoid confusion." (Individual, Missoula, MT - #7257)

Response: The Final Yosemite Valley Plan/SEIS uses the Cowardin Wetland definition in conjunction with the National Park Service and U.S. Army Corps of Engineers’ definitions of wetlands. The text in Vol. IA, Chapter 3, Affected Environment, Wetlands, has been modified to clarify how the classification system was applied and how wetlands are defined by the National Park Service.

494. Public Concern: The National Park Service should clarify the term "riparian" in the Yosemite Valley Plan.

"Equally discombobulating [as the definition of wetland] is the use of the term ‘riparian’ throughout the documents. On page 7-9 of the executive summary you define ‘riparian’ as those areas that are on or adjacent to rivers and streams . . .’ This is practically verbatim to your definition for wetlands just cited. ‘‘Riparian’ and ‘wetland’ are not synonyms and usage varies greatly. We often use the terms in combination when speaking of general situations that include both.’ (Hansen, et al 1995) While resource managers may use the terms in combination, they do make the distinction and they do define them differently. Last year, when conducting the National Wetland Inventory for Zion National Park in Springdale, UT, I was not only charged with ground-truthing the park’s wetlands but also the riparian polygons. I used a draft document (that should be published as a final document by now) called ‘A System for Mapping Riparian Areas in the Western United States.’ (USFWS 1997) I would like to share the F&WS discussion of the concept and definition of ‘riparian’ with you: ‘Riparian is viewed from many perspectives. Older and more classical riparian interpretations identify primarily woody vegetation associated only with lotic systems. Recent interpretations include a broader view involving both lotic and lentic systems, surface and subsurface water influences, and natural forces and human-induced activities that affect the woody and emergent vegetation. Although riparian areas are closely associated with water and topographic relief, they are independent from either wetland or upland. Riparian areas lack the amount or duration of water usually present in wetlands, yet are ‘wetter’ than adjacent uplands.’ (USFWS 1997) ‘Riparian refers to areas of vegetation associated with perennial or intermittent lotic and lentic systems. The vegetation of these areas is recognizable as distinctly different species and/or growth forms compared to adjacent vegetation. Riparian vegetation is usually transitional between wetland and upland. The vegetation is often found in river valleys, stream corridors, and other areas contiguous with, and affected by, the surface or subsurface hydrologic features of rivers, streams, drainage ways, and lakes.’ (USFWS 1997) The National Park Service should use the F&WS definition of riparian throughout their documents. Please stop interchanging riparian with wetland. It is patently false and extremely misleading to both those who understand the distinction and those that don’t." (Individual, Missoula, MT - #7257)

Response: The term riparian can be defined a number of ways. For the purposes of the Final Yosemite Valley Plan/SEIS discussion on wetlands, riparian areas are considered to be a subset of wetlands and, therefore, their definitions will be similar. Similarly, meadow areas in the Final Yosemite Valley Plan/SEIS were also considered to be a subset of wetlands. Thus, the terms riparian wetland and meadow wetland refer to the subtype of wetland. The National Park Service agrees that these terms can be confusing; therefore, the text in Vol. IA, Chapter 3, Affected Environment, Wetlands, has been modified to clarify the discussion of different wetland types.

Section 4.4 ~ Geology, Geohazards, and Soils

"Yosemite Valley is an inherently risky place," declares one person in response to the Geologic Hazards section of the Draft Yosemite Valley Plan/SEIS. Several other respondents agree while offering diverse suggestions on how the National Park Service should address potential safety hazards posed by rockfall and mitigation of impacts on geologic resources resulting from management decisions.

Accusing the National Park Service of ignoring potential geohazards within Yosemite Valley, one individual insists the Yosemite Valley Plan should require the removal of all public facilities that may be affected by catastrophic seismic activity. "These seismic hazards are good reasons, legal and otherwise, to provide the public with a planning alternative that will significantly clean buildings and other facilities out of Yosemite Valley," this person contends. The California Governor’s Office of Planning and Research calls upon the National Park Service to expand analysis of potential hazards from rockfalls both outside and within Yosemite Valley. Specifically, the state agency challenges a statement in the Executive Summary of the Draft Yosemite Valley Plan/SEIS that dismisses mitigation for rockfall hazards outside of the Valley. The agency contends that rockfall-caused road damage and closures on State Highway 140 over the past few decades is sufficient evidence to warrant further analysis of potential geohazards outside the Valley. The agency also notes the 1996 blow-down of trees at Happy Isles as justification for further investigation of potential rockfall-induced airblast hazards. While agreeing that public safety must receive priority consideration, a nongovernmental organization admonishes Park leadership to evaluate public facilities in hazard zones individually rather than collectively. "Not all structures in the floodplain or rockfall zones are equally at risk," the organization argues and suggests historical significance should be factored into risk assessments.

The conservation of geologic resources within the Valley is also a topic of concern for those responding to the Draft Yosemite Valley Plan/SEIS. One individual believes the plan’s geologic analysis is insufficient because it fails to identify the soils of the El Portal section of the Merced River as an Outstandingly Remarkable Value (ORV) under the Wild and Scenic River Act. Increased human activity in El Portal, this individual warns, will impact the conservation of topsoil in the area and therefore necessitates recognition as an Outstandingly Remarkable Value.

674. Public Concern: The Yosemite Valley Plan should remove facilities and restrict public access from areas within rockfall and rockfall-induced air blast hazard zones.

"The NPS administrators and planners continue to ignore the serious hazards of rockfall and rockfall tree blow down in the Valley. Almost every year people have been killed in Yosemite Valley from these hazards. There is a fundamental flaw in the Yosemite safety planning. . . It appears little or nothing is being done to remove facilities in the more dangerous areas of the Valley for public safety. . . Under California law, if government officials ignore seismic hazards to the public, and in the event of an earthquake catastrophe, they may be held personally liable for damages. These seismic hazards are good reasons, legal and otherwise, to provide the public with a planning alternative that will significantly clean buildings and other facilities out of Yosemite Valley." (Individual, Mountain View, CA - #6140)

Response: The Yosemite Valley Geologic Hazards Guidelines provided in Vol. II, Appendix C of the Final Yosemite Valley Plan/SEIS will be used to evaluate all new and existing facilities with respect to rockfall hazards within the Valley to reduce the exposure of the public and park staff to such hazards.

Geologic hazards have been a primary concern in the development of the alternatives in the Final Yosemite Valley Plan/SEIS. Discussion of this issue is presented in Vol. IA, Chapter 2 under Development Considerations; is included within each alternative under specific actions; is included in Vol. IA, Chapter 3, Affected Environment; and is addressed in Vol. IB, Chapter 4, Environmental Consequences. Geologic hazards are also represented graphically in Volume 1c.

452. Public Concern: The Yosemite Valley Plan should include an analysis of geologic hazards between Yosemite Valley and El Portal.

"On page 4-12 of the Executive Summary, the DEIS states that Out-of-Valley areas were not included in the analysis of geologic hazards because ‘the relative risk of rockfall in these areas would be negligible due to lack of evidence of past rockfall events.’ Wieczorek, et al., (1992) present abundant evidence of past rockfalls in the Merced Gorge and farther downstream to El Portal, which is outside Yosemite Valley. The rockfalls that have damaged (and closed) State Highway 140 during the past few decades are noteworthy. . . The effect of rockfalls on Highway 140 is crucial in planning what should stay in the Valley and what should be moved (or retained) elsewhere. Therefore, we recommend that the DEIS geologic hazard analysis be expanded to include the areas between the Valley and El Portal." (Governor’s Office on Planning and Research, Sacramento, CA - #6584)

Response: With the exception of the Arch Rock Entrance Station, there are no permanent structures planned for the area between Yosemite Valley and El Portal. Also, traffic along the roadway in the area is considered transitory and not a permanent population. The transitory nature of the traffic allows little exposure at any one time to potential geologic hazards. For these reasons, this area was not included in the analysis of geologic hazards for Yosemite Valley.

450. Public Concern: The Yosemite Valley Plan should include an analysis of potential hazards from rockfall-induced air blasts in Yosemite Valley.

"We did not find mention of the hazards from air blast induced by rockfalls. This phenomenon could cause significant property damage and human injury in locations that have stands of tall, shallow-rooted trees. The blow-down of trees at Happy Isles by a rockfall in 1996 is an example of such a hazard. We recommend that the final EIS explore the potential for air blast hazards, using geographic information system (GIS) analysis to map where talus and rockfall shadow zones coincide with stands of forest, particularly shallow-rooted conifers." (Governor’s Office of Planning and Research, Sacramento, CA - #6584)

Response: The National Park Service understands there may be potential danger from air blast during a rockfall event. However, the air blast effect is not common and there is very little scientific data on which to base an analysis. The National Park Service has consulted with the U.S. Geological Survey, and determined that until more research has been conducted, the potential hazard for this aspect of rockfall cannot be addressed at this time.

673. Public Concern: The National Park Service should weigh historical significance against geologic hazard risks when considering removal of structures within Yosemite National Park.

"We are concerned that perhaps too much emphasis and faith is being placed in the floodplain and rockfall maps. We recognize the threats posed by both of these natural forces, but also believe that assessing risk is not as simple as drawing a line across a map. Not all structures in the floodplain or rockfall zones are equally at risk, and there is a considerable margin of error in predicting these events. Nobody wants to play a numbers game where human safety is concerned, but Yosemite Valley is an inherently risky place, and marginally increased risk must be weighed against other factors, including historic significance. Where the predicted extent of rockfall zones and floodplains directly determines whether historic resources are preserved or destroyed, we believe that these determinations must be more closely assessed." (Non-Governmental Organization, San Francisco, CA - #8925)

Response: Vol. II, Appendix C, Yosemite Valley Geologic Hazards Guidelines, in the Final Yosemite Valley Plan/SEIS, discusses the process of evaluating whether or not a historic structure would be removed from a geologic hazard zone. If the functions those structures support are in the categories of "essential" or "hazardous," the structure may remain as long as the functions are relocated to safer areas and the structure is adapted for more appropriate uses.

675. Public Concern: The Yosemite Valley Plan should identify soils in the El Portal section of the Merced River as Outstanding Remarkable Values.

"Soils in the El Portal section of the WSR were not identified as an ORV. The soils in this area are very sensitive to erosion given that they are very dry and there is very little topsoil. Because the soils are so fragile they should have been designated as an ORV. Any construction or trampling from recreation will easily impact plants and debris that hold topsoil in place." (Individual, El Portal, CA - #7026)

Response: This concern is acknowledged; however, it is outside the scope of the Yosemite Valley Plan. The definition of Outstandingly Remarkable Values (ORVs) was revised in the Merced Wild and Scenic Comprehensive Plan/FEIS based on a clearer understanding of the Wild and Scenic Rivers Act. The Final Yosemite Valley Plan/SEIS would protect those Outstandingly Remarkable Values and is not revisiting their definition. Susceptibility to erosion by itself is not sufficient to qualify soils as an Outstandingly Remarkable Value.

Section 4.5 ~ Vegetation

Protecting and enhancing the vegetative components of impacted ecosystems in Yosemite Valley is a concern for many draft plan respondents. Citizens address a wide spectrum of loosely related topics that include the adequacy of analysis of vegetative impacts, the restoration of meadows, and the removal of trees in Yosemite Valley. Comments concerning the use of prescribed fire round out this section.

The adequacy of analysis regarding vegetative impacts is incomplete or needs clarification, according to some respondents. Potential inconsistencies regarding the identification of rare, threatened, and endangered floral species in Volume 1b of the Draft Yosemite Valley Plan/SEIS should be clarified, according to one person. The Final Yosemite Valley Plan/SEIS should address the cumulative impacts on vegetation from increased human populations in El Portal, according to several individuals. Similarly, one conservation organization believes that the Final Yosemite Valley Plan/SEIS should acknowledge the potential impacts increased automobile traffic in El Portal may have on roadside vegetation.

The impact of humans on Yosemite Valley’s meadows is manifest and should be addressed in the Yosemite Valley Plan, according to many people. Several respondents believe that the National Park Service should restore sensitive habitats–in particular meadow, black oak, and riparian areas. In addition, one individual feels that that the restoration of meadows could be accomplished by constructing terraces in the Merced River east of the terminal moraine.

In addition to the proponents of meadow protection, many respondents support the preservation of the Valley’s trees. One public hearing attendee pleads, "Don’t remove the trees, please. I think that they deserve to continue living. Maybe they are in the wrong place, but it’s not their fault." Another constituent opposes the removal of the "beautiful tall pine trees which give the Valley so much of its present day character." Responding to a tangentially related topic, one respondent believes that the Yosemite Valley Plan should require low-impact management techniques, such as removing structures and planting vegetation, for the restoration of closed campgrounds. Any removal of trees in these campgrounds "could deface these sites for generations," according to this individual.

Not all respondents believe that the restoration of Yosemite Valley vegetation and habitat is of paramount concern. "Is it that essential that we recover the former oak population at great expense and restriction of humans?" one person inquires. Others suggest that stock grazing be allowed in the meadows of Yosemite Valley. "Meadows should not be closed due to unsubstantiated claims of over-grazing or because of excessive use by another user group," asserts a representative of a recreational organization.

The use of fire is another vegetative management tool that elicits several comments. While some believe the National Park Service should utilize carefully managed prescribed fire to improve habitat conditions, others feel that the National Park Service should eliminate all controlled burning in Yosemite National Park. The National Park Service should consider mechanical treatments to enhance Yosemite National Park vegetation, according to another, "where fire cannot by itself sufficiently enhance the park’s pine/oak forest/meadows mixture."

633. Public Concern: The National Park Service should address potential inconsistencies regarding identification of rare, threatened, and endangered floral species in Volume 1b of the Draft Yosemite Valley Plan/SEIS.

"There appears to be a major error in the conclusions concerning vegetation in Volume 1B Environmental Consequences. On page 4.2-41, the Conclusion paragraph states: ‘There are no known federal or state listed plant species that occur within the Valley or potentially affected out-of-valley areas . . . with only four that are state special concern and three that are federal species of concern.’ This was also repeated on page 4.2-42 second column, third paragraph. This appears to be contradicted by page 4.2-40 in the El Portal paragraph which says, ‘There are currently one federal plant species of concern (Congdon’s lomatium), four state listed rare species, (Yosemite Onion, Tompkin’s sedge, Congdon’s Wooly Sunflower, and Congdon’s Lewisia) . . . that occur within the general El Portal area. Radiating impacts from trampling would continue to occur to all of these species, except Yosemite Onion and Congdon’s lomatium . . . and would be increased . . . potential impacts would occur to Tompkin’s sedge . . . from development of out-of-valley parking and employee parking.’ It goes on to say that they would salvage and replant Tompkin’s sedge resulting in minor adverse impacts. It also mentions continuing adverse impacts with roadside maintenance to Tompkin’s sedge, Congdon’s woolly sunflower and Congdon’s Lewisia. This contradiction is repeated under the conclusions concerning vegetation for all the rest of the alternatives 3 through 5 in addition to alternative 2. See pages 4.3-20 under Conclusion, 4.4-21 Conclusion and 4.5-21 under Conclusion." (Individual, Columbia, CA - #7149)

Response: These errors have been corrected in the Final Yosemite Valley Plan/SEIS, as well as in the Biological Assessment for the Final Yosemite Valley Plan/SEIS. The magnitude of impact to rare, threatened, and endangered plant species in El Portal has been changed to moderately adverse, and the text has been corrected.

543. Public Concern: The Yosemite Valley Plan should address the cumulative impacts on vegetation from increased human populations in El Portal.

"The DVP does not consider the related and cumulative impacts of increasing human population in El Portal, leading to trampling of vegetation (which means increased soil erosion, fragmentation of habitats, soil disturbance and invasion of exotic plants, and population decline of ecologically sensitive species that are not necessarily species listed as sensitive)." (Conservation Organization, Yosemite, CA - #7883)

"In El Portal, the human population will at least double from 600 residents to over 1200 residents plus 370 tourist automobiles which could add another 400 to 800 people impacting a limited area that had very limited impacts before. It also says that impacts would be limited due to implementation of site-specific mitigation measures. These are undefined. In addition, mitigation usually means trying to limit human activities, or relocating T & E species. . . El Portal is a narrow canyon with poison oak and steep hillsides naturally limiting the human population to the riparian corridor, upland benches and roads for recreation. Additionally, non-native plant populations are already reaching crisis sizes with the Park Service doing relatively little to impact their populations. Development equals a net loss of habitat and fragmentation of ecosystem processes. Innumerable variables work in concert to create habitats for species. Restoration should not be used as a justification for development and disturbing habitat as we know that ecosystems are very complex and very difficult, if not impossible, to restore." (Individual, El Portal, CA - #7026)

Response: The existing environment in El Portal, including impacts to vegetation by the current level of use, is described in Vol. IA, Chapter 3, Affected Environment. Existing impacts specific to rare, threatened, and endangered species in El Portal are also discussed in Vol. IB, Chapter 4, Environmental Consequences. Cumulative impacts to vegetation and rare, threatened, and endangered species caused by the proposed increased El Portal population have been addressed in all alternatives.

544. Public Concern: The Yosemite Valley Plan should address potential negative impacts on roadside vegetation from increased automobile traffic in El Portal.

"The DVP does not consider the related and cumulative impacts of increasing human population in El Portal, leading to particulate deposits from exhaust on roadside vegetation will decrease plant productivity as well as enter pollutants into the food chain and the aquatic ecosystem as a non-point source of pollution." (Conservation Organization, Yosemite, CA - #7883)

Response: The Final Yosemite Valley Plan/SEIS considers potential impacts to vegetation in El Portal (see Vol. IB, Chapter 4, Environmental Consequences), and also evaluates potential impacts to air and water quality. The effects of non-point source runoff have been included in Vol. IA, Chapter 3, Affected Environment. Ongoing studies in Yosemite National Park and in the Sierra Nevada are examining the effects of external and internal air pollutants on natural resources, including vegetation. The National Park Service participates with the California Air Resources Board in monitoring air quality conditions within the park relative to regional standards.

392. Public Concern: The Yosemite Valley Plan should provide for the restoration of sensitive habitats.

"I support removing roads and utilities to restore sensitive meadow areas, as well as restoring any other sensitive types of habitat by removing structures and limiting access. I am a big fan of restoring areas to healthy and natural conditions. I feel that wherever possible, removing structures and restoring the area should be done. I am also a big fan of continuing to monitor areas after they have been restored. All restoration areas should have some kind of monitoring and evaluation schedule set up, as well as continued maintenance until the area has fully recovered." (Individual, Columbia, CA - #4235)

"There is too much emphasis in the various alternatives in the draft plan on moving facilities from one place to another and on constructing new facilities in places unimpacted in the past. Emphasis should be placed on restoration under a clearly articulated set of priorities." (Conservation Organization, Fresno, CA - #7881)

Response: As stated in the Final Yosemite Valley Plan/SEIS, the two primary purposes of Yosemite National Park, are to preserve the resources that contribute to the park’s splendor and uniqueness, and make the varied resources of Yosemite National Park available to people for their enjoyment, education, and recreation, now and in the future (Vol. IA, Chapter 1, Purpose and Need). All alternatives presented in the Final Yosemite Valley Plan/SEIS seek to achieve an appropriate balance between visitor use and enjoyment and protection and preservation of the cultural and natural resources that make up Yosemite National Park. The focus of the Yosemite Valley Plan is on protecting and restoring an ecological system that is sustainable over time within the framework of visitor use and long-term management, and an emphasis has been placed on defragmenting critical habitats and providing for river protection and the restoration and function of natural processes.

The Preferred Alternative in the Final Yosemite Valley Plan/SEIS has identified meadows, riparian areas, and California black oak woodlands as highly valued resources that will receive the highest priority for protection and restoration. All restoration actions are intended to meet the goals of the General Management Plan, but specific objectives vary from site to site depending on site characteristics. Some site restoration objectives are also guided by cultural landscape and ethnographic resource issues. The Preferred Alternative in the Final Yosemite Valley Plan/SEIS also calls for the restoration of natural water flow patterns through the removal or modification of roads, paved paths, and parking lots. This would also lead to altered soil moisture with associated shifts in vegetation. The National Park Service would also continue to control non-native plant species, and place an emphasis on defragmenting vegetation through the center of Yosemite Valley to improve ecosystem function. This would include linkages of wetlands and riparian areas to current and potential meadow sites. These treatments are proposed to varying degrees in each of the action alternatives, with consequences outlined in Vol. IB, Chapter 4, Environmental Consequences of the Final Yosemite Valley Plan/SEIS.

233. Public Concern: The Yosemite Valley Plan should protect meadow, black oak, and riparian areas from pedestrian traffic.

"Some areas, which are in need of protection, are the meadow areas, the California black oak communities, and the riparian habitats. We respect that the protection of these areas is not always compatible with the goals of tourism in the area, however, with significant interpretive and educational services to visitors to the Park, the long-term protection may be achieved. Immediate preservation actions that may be taken could be the construction of raised wooden paths in certain areas of the meadow and California black oak habitats, along with construction of paths through a limited area of the riparian habitat. We believe that the only way that visitors will respect the ecological significance of the area is through educational programs that highlight the fragile nature of such communities." (Individual, San Luis Obispo, CA - #1510)

Response: The Preferred Alternative in the Final Yosemite Valley Plan/SEIS has identified meadows, riparian areas, and California black oak woodlands as highly valued resources that would receive the highest priority for protection and restoration. In areas where continuing or new development impacts are unavoidable, the Final Yosemite Valley Plan/SEIS has identified a series of mitigations that would help minimize short-term impacts as well as impacts over the long term (see Chapter 2, Alternatives). These mitigations include site-specific planning to avoid direct impacts to long-lived species such as black oak trees, as well as fencing, installation of educational signs and construction of boardwalks, and delineation of pathways to allow people to move through these areas while minimizing their impacts. Other not-so-visible impacts such as encroachment of meadows by non-native species would continue to be managed by vegetation management staff in conjunction with fire management and other National Park Service programs involved in the protection and long-term management of the park's vegetative resources.

The River Protection Overlay in the Merced River Plan/FEIS provides for the protection of resources that connect to the Merced River system, which include most meadow and riparian resources in Yosemite Valley. The width of the River Protection Overlay is 150 feet above 3,800 feet elevation and 100 feet below, measured from ordinary highwater. That width is based on the area needed to encompass enough riparian and adjacent upland vegetation and habitat and to allow for a large enough area for natural processes to prevail – one of the five primary goals of the 1980 General Management Plan. Implementation of the River Protection Overlay would result in long-term benefits to the river system and to the vegetation communities that are linked to it.

336. Public Concern: The National Park Service should restore meadows by constructing terraces in the Merced River east of the terminal moraine.

"There are some good options for the park that are not considered in any of the plans. . . A system of terraces in the river east of the terminal moraine ridge to increase the groundwater level in order to restore meadows." (Individual, Coulterville, CA - #3724)

462. Public Concern: The Yosemite Valley Plan should prohibit the removal of any trees in Yosemite Valley.

"Don’t remove the trees, please. I think that they deserve to continue living. Maybe they are in the wrong place, but it’s not their fault." (Public Hearing, San Jose, CA - #20520)

Response: Active removal of trees may occur during Yosemite Valley Plan-related restoration and redevelopment actions, particularly where dying trees pose a hazard to the public, to workers, or to structures and utilities in the area, similar to the hazard tree program currently in place in Yosemite National Park. Also, planted giant sequoias in Yosemite Valley may be removed in areas that are being restored to highly valued resource vegetation types. Sequoias are not native to the Valley, and these trees have reached reproductive age and could potentially spread beyond the individual planted (historic) trees. Fruit trees at the Curry Orchard would be removed due to their impact to wildlife species in the area.

The Merced River Plan/FEIS calls for the implementation of a River Protection Overlay to allow natural processes to prevail (one of the goals of the 1980 General Management Plan), which would allow for ecological restoration of large portions of the east end of Yosemite Valley. This restoration and the preservation of cultural landscapes in Yosemite Valley would lessen the chances of survival over time of certain tree species in portions of Yosemite Valley.

For example, restoration of original riparian and cut-off channels would lead to larger areas of saturated soils. As soils become water-saturated for longer periods of time, water-intolerant trees such as ponderosa pines and incense-cedars would have increased rates of mortality. Some Valley landscapes have not been burned for a long time, resulting in the establishment of unnaturally high densities of trees (Vol. IA, Chapter 3, Affected Environment); during restoration, prescribed burns would be introduced into these areas and would cause high levels of tree mortality. As these and other natural processes are restored, impacts to trees, particularly conifers, would occur over time, leading to a more open landscape more characteristic of the scene first encountered by Euro-American explorers in Yosemite Valley in the 1850s.

669. Public Concern: The Yosemite Valley Plan should require the retention of tall pine trees in Yosemite Valley.

"I oppose restoring vegetation in such a way as to eventually eliminate the beautiful tall pine trees which give the Valley so much of its present day character. Doing this in the name of some distorted view of what the place looked like 100 years ago bears no relevance to what is most enjoyable for visitors of today. I still recall my first impression of Yosemite Valley. On my first visit, I was overwhelmed by the enormous (especially for me as non-Californian) pine trees that fit so well with the larger-than-life magnificent views of cliffs, and monoliths and water coming down everywhere." (Individual, Los Altos, CA - #3165)

Response: The Merced River Plan/FEIS calls for the implementation of a River Protection Overlay to allow natural processes to prevail (one of the goals of the General Management Plan), which will allow for ecological restoration of large portions of the east end of Yosemite Valley. The Final Yosemite Valley Plan/SEIS would implement the guidance and direction of the Merced River Plan/FEIS, which could result in the removal of trees in areas that are unnaturally forested. In addition, preservation and restoration of the cultural landscapes integral to the natural and cultural resources of Yosemite Valley will lessen the chances of the survival of certain tree species in portions of Yosemite Valley over time.

For example, restoration of original riparian and cut-off channels will lead to larger areas of saturated soils. As soils become water-saturated for longer periods of time, water-intolerant trees such as ponderosa pines and incense-cedars will have increased rates of mortality. Some Valley landscapes have not been burned for a long time, resulting in the establishment of unnaturally high densities of trees (See Vol. IA, Chapter 3, Affected Environment); during restoration, prescribed burns would be introduced into these areas and would cause high levels of tree mortality.

As these and other natural processes are restored, impacts to trees, particularly conifers, would occur over time, leading to an open landscape more characteristic of the scene first encountered by Euro-American explorers in the Yosemite Valley during the 1850s. Active removal of trees may occur during restoration and redevelopment actions, particularly where dying trees pose a hazard to restoration workers or to structures and utilities in the area (similar to the hazard tree program currently in place in Yosemite). Giant sequoias planted in Yosemite Valley may be removed in areas that are being restored to highly valued resource vegetation types. Sequoias in the Valley are not natural, and these trees have reached reproductive age and could potentially spread beyond the individual planted (historic) trees. Fruit trees at the Curry Orchard would be removed due to their impact to wildlife species in the area.

670. Public Concern: The Yosemite Valley Plan should require low-impact management techniques for restoration of closed campgrounds.

"I urge you to limit restoration of closed campgrounds to removing structures, pavement and subgrade, and possibly some underground utilities; then loosening soil and planting, where necessary. I see no merit in removing imported fill to restore the topography of the closed campgrounds. It would add to the cost of restoration - and likely postpone its start. It would add pollution and traffic of its own. It would destroy existing vegetation, particularly in Camp 9 and Lower River, where revegetation is already well underway. By removing trees, it could deface these sites for generations." (Individual, Oakland, CA - #3835)

Response: All restoration actions called for in the Final Yosemite Valley Plan/SEIS are intended to meet the goals of the General Management Plan, but specific objectives vary from site to site depending on site characteristics. Some site restoration objectives are also guided by cultural landscape and ethnographic resource issues. Ecological restoration techniques in Yosemite National Park, as in many other national parks, incorporate a variety of low- and high-impact techniques to accomplish restoration goals. For example, watershed rehabilitation work at Redwood National and State Parks relies almost exclusively on heavy equipment to restore topography and thus drainage systems, topsoil location, and, eventually, vegetation as well. For recent removal of concession facilities and restoration of Giant Forest in Sequoia National Park, heavy equipment was used to restore topography and site characteristics most advantageous to the re-establishment of ecosystem function over time. These methods have also been used successfully in Yosemite National Park for over a decade in such areas as Cook's Meadow (removal of an old road bed and restoration of wetlands, 1996 to present), Housekeeping Camp (removal of riprap and re-establishment of riparian vegetation, 1996-1998), and the Schoolyard oak woodland (1987-1992). Low-impact work generally involves the final aspects of restoration of a site, including seed collection, planting, and application of materials to promote better soil and nutrient conditions (such as duff, forest litter, and, occasionally, soil amendments).

These design-level details for specific elements of the action alternatives are not fully developed in the document. This is because additional planning and analysis would be necessary before these projects can be implemented. Over a decade of restoration work in Yosemite National Park has given the National Park Service information on the techniques that are most appropriate for restoring various portions of the park's many ecological units, including meadow, wetland, riparian, California black oak woodland, and upland areas in Yosemite Valley.

230. Public Concern: The National Park Service should reassess the Yosemite Valley Plan’s requirement for the restoration of oak populations in Yosemite Valley.

"As for the benefits from the oak population, here too we should take whatever steps are feasible to reverse their disadvantageous decline. However, the photos don’t make this need clear nor is it obvious that human activities have caused the decline. Could other natural events beside gradual human build-up over the century have caused the depopulation? . . . And is it that essential that we recover the former oak population at great expense and restriction of humans?" (Individual, Sanger, CA - #2293)

Response: Yosemite Valley's oak trees are recognized as critical contributors to the Valley's natural ecosystem as well as to the cultural landscape. The decline of this vegetation type has been recorded over the years through such studies as Gibbons and Heady (1964) and Heady and Zinke (1978). According to the latter report, "The openness of the forest and the dominance by the two species [California black oak and ponderosa pine] probably resulted from periodic fires and the efforts of Indians to maintain orchards of California black oak for acorns. Both these factors have been greatly reduced for over 100 years." Other actions that have further reduced stands of black oaks include development of housing, roads, and visitor and administrative areas. These actions and activities have also deterred black oaks from reproducing, both because of heavy use levels and/or pavement in developed zones, and competition by native and non-native plants in areas no longer maintained by fire. Oaks in other areas of the Valley that do not receive these stresses are reproducing at natural rates, resulting in variably aged stands of seedlings, saplings, and overstory trees in distinctive age classes. In developed or impacted stands, all oaks are mature trees, with no seedlings and saplings to replace mature trees as they die.

Because of their significance as both cultural and natural resources, the National Park Service has focused on protecting existing stands of oaks, restoring impacted stands, and avoiding impacts to these long-lived trees in areas with development. In the Final Yosemite Valley Plan/SEIS, the California black oaks are also one of the highly valued resource vegetation types (see Vol. IA, Chapter 2, Alternatives), and have been used (in conjunction with the other highly valued resources) to guide land-use planning decisions during the development of alternatives. All of the action alternatives in the Final Yosemite Valley Plan/SEIS call for restoration of California black oak stands with removal of the Ahwahnee tennis courts and relocation of the Superintendent's House (Residence #1).

287. Public Concern: The Yosemite Valley Plan should allow grazing in meadows in Yosemite National Park.

"Meadows should not be closed due to unsubstantiated claims of over-grazing or because of excessive use by another user group. Actions limiting use of any grazing area should be after a monitoring program acceptable to both users and administrators indicates a need for action, and after review by experts in range management. Responsible cattle grazing, where allowed by agency regulation, is an acceptable component of the ‘Multiple Use’ concept and should be tolerated by all users as trails are not closed to other user groups." (Recreational Organization, No Address - #3701)

"Grazing of meadows by work animals should be implemented to help keep them open and promote healthy stands of perennial grasses. Hay transportation and feeding should be controlled, with only weed-free certified hay, covered when transported, and with feeding locations controlled to help prevent the spread of noxious weeds." (Individual, Sutter Creek, CA - #7305)

Response: This concern is acknowledged; however, it is outside the scope of the Yosemite Valley Plan. Grazing in low-elevation meadows in Yosemite National Park does not meet the goals of the 1980 General Management Plan nor of the 1916 National Park Service Organic Act, which seeks to preserve resources while providing for the enjoyment of future generations. In general, grazing is not authorized within Yosemite National Park. Grazing does not facilitate the restoration of ecological systems or create or enhance habitat for the diversity of aquatic, plant, and wildlife species the National Park Service is mandated to protect and preserve.

In Yosemite Valley, grazing activities were eliminated in 1924 because of the damage to scenic and meadow conditions. Impacts to Yosemite's meadows from grazing were noted as early as the 1880's in the annual Commissioner's Reports. The 1885-1886 report states in part: "The truth is that, under the strain of over-pasturage, the best meadow lands are being injured, while all of them show thickets of young pines, willows, and cottonwoods, and some of them are so entirely overgrown as to have passed out of pasturage classification into that of a woodland." According to Gibbons and Heady (1964), "Heavy grazing allows seedlings to become established by reducing competition from sedges, grasses, and broad-leaved plants. Trampling creates drier conditions by compacting the soil and, in wet areas, by forming a rough, ridged surface which increases evaporation and drying. Exposure of mineral soil provides an excellent seedbed...which favors tree seedling establishment". Justification for the elimination of grazing in Yosemite Valley remains as valid today as it was over 100 years ago.

Grazing of saddle and pack stock is allowed under careful management in some areas of the Yosemite Wilderness. No actions in the Yosemite Valley Plan would affect current grazing activities or management within wilderness, which is outside the scope this plan.

409. Public Concern: The National Park Service should utilize carefully managed prescribed fire to improve habitat conditions.

"I feel that prescribed fire can and must be performed in an ever more sophisticated manner to avoid partial results and disasters as have occurred elsewhere in recent times. With that in mind, fire managers and resource managers must cooperate ever more closely to promote habitats that approach presettlement conditions." (Individual, Walnut Creek, CA - #3565)

Response: This concern is acknowledged; however, it is outside the scope of the Yosemite Valley Plan. Yosemite National Park has developed a prescribed burning program that manages vegetation and improves habitat conditions for many species. It has long been recognized that fire is an integral part of the forces that have created Yosemite's natural and cultural landscape, and these activities, as described in Vol. IA, Chapter 3, Affected Environment, and Vol. IB, Chapter 4, Alternative 2, would continue as proposed in the Final Yosemite Valley Plan/SEIS. Specific prescriptions for environmental conditions must meet the specific objectives of each prescribed fire, including safety and minimization of smoke and visitor disturbance. Site-specific restoration and habitat management goals are covered in various portions of the 1990 Fire Management Plan, the 1993 Resources Management Plan, and the 1997 Vegetation Management Plan.

261. Public Concern: The National Park Service should eliminate controlled burning in Yosemite National Park.

"Please end all ‘controlled burning’ within this (and all) Park systems. Allow private (and supervised) clearing and utilization of wood resources." (Individual, Planada, CA - #20513)

Response: This concern is acknowledged; however, it is outside the scope of the Yosemite Valley Plan. However, prescribed fire is a valid resource management and fuel reduction method and will continue under the directions set forth in the 1990 Fire Management Plan.

410. Public Concern: The National Park Service should consider mechanical treatments to enhance Yosemite National Park vegetation.

"Where fire cannot by itself sufficiently enhance the Park’s pine/oak forest/meadows mixture, then some mechanical removal of the Valley’s pine overstory along the lines of a natural landscape design should be promoted." (Individual, Walnut Creek, CA - #3565)

Response: This concern is acknowledged; however, it is outside the scope of the Yosemite Valley Plan. Yosemite National Park currently uses mechanical treatments in areas of the park where the use of fire is infeasible, such as around structures and in areas with high levels of human use where smoke conditions could pose serious health risks and/or where ground fuels have been so depleted that fires would not achieve vegetation management objectives. These actions are meant to either take the place of fire as a natural process or to aid in the reintroduction of fire at some future date. Site-specific prescriptions are developed for these mechanical removal projects, similar to prescriptions followed during prescribed burns. These activities as described in Vol. 1a, Chapter 3, Affected Environment, and in Vol. 1b, Chapter 4, Environmental Consequences) would continue as proposed in the Final Yosemite Valley Plan/SEIS. Site-specific restoration and habitat management goals are covered in various portions of the 1990 Fire Management Plan, 1993 Resources Management Plan, and 1997 Vegetation Management Plan.

Section 4.6 ~ Wildlife

This section contains disparate concerns regarding the preservation of Yosemite Valley’s plant and animal species. Comments regarding wildlife impacts resulting from projects in Wawona and El Portal begin this section. Public concerns involving impacts on wildlife and fisheries from bridge removal and road building follow. This section concludes with suggestions to protect the great grey owl and a request to remove wildlife from Yosemite Valley.

One civic organization believes that the Final Yosemite Valley Plan/SEIS should address potential Wawona housing project impacts on wild species. This group believes the Draft Yosemite Valley Plan/SEIS "fails to address the housing project’s potential adverse impacts on plant and wildlife species protected under state and federal law." The Final Yosemite Valley Plan/SEIS should not only identify the presence of special status species at the proposed housing site in Wawona, but it should also contain detailed plans to mitigate any adverse impacts this development may have on those species, according to one organization. Taking this concept one step further, a conservation organization exhorts the National Park Service (NPS) to evaluate the cumulative impacts of an increased human population in El Portal on wildlife.

In addition to the potential impacts of the Wawona and El Portal projects, many proponents of wildlife preservation believe the Final Yosemite Valley Plan/SEIS should address the impacts of bridge removal on wildlife. Some respondents feel such an action will disturb the animals’ movement patterns. "I have personally observed deer and other wildlife utilizing the existing historic bridges to cross the Merced River," remarks one business representative. "Therefore, elimination of the bridges may also result in significant adverse impacts to the movement of wildlife and result in more wildlife being injured as attempts are made to cross the few remaining auto and bus bridges that cross the Merced River. This impact was not addressed or analyzed in the SEIS."

Although replacing bridges may improve the health of the Merced River’s fisheries, another respondent notes the lack of analysis in the Draft Yosemite Valley Plan/SEIS regarding the deleterious effects of asphalt on fish. "The toxicity of oil pollution to aquatic populations has been seriously underestimated," according to this person. An aficionado of fishing believes that the National Park Service should establish an intensive trout management program for the Merced River. "In my judgment, there is no excuse for the disappearance of the trout from the Merced River in the Valley," according to this individual. "Under the present situation, the Merced River running through the Valley is simply being wasted as a marvelous family fishing resource and opportunity."

While numerous respondents comment on impacts to wildlife in general, some individuals cite species-specific examples. One such individual feels that the Final Yosemite Valley Plan/SEIS should account for any potential effects the proposed traffic increase on the Old Coulterville Road may have on great grey owls. Another grey owl supporter questions the logic behind locating the National Park Service stable at McCauley Ranch. "An NPS stable at South Landing would probably be better for the great gray owl population than one at Foresta because of less proximity to a large meadow," according to this individual.

Although most respondents who cite wildlife in their responses to the Draft Yosemite Valley Plan/SEIS exhort wildlife protection, one individual believes the Yosemite Valley Plan should require an aggressive management plan to remove bear and deer populations from Yosemite Valley. This individual protests, "Bear and deer have no place in Yosemite Valley! They cannot be educated to conserve and preserve anything. There are plenty of places where they can and should be protected and allowed to roam, but not there." Removing deer and bear populations from the Valley will improve vegetation, traffic flow, and ultimately, the visitor experience, according to this individual.

458. Public Concern: The Yosemite Valley Plan should address housing project impacts on plant and wildlife species.

"The Valley Plan’s SEIS likewise fails to address the housing project’s potential adverse impacts on plant and wildlife species protected under state and federal law. Although the Park Service’s Biological Assessment for the Valley Plan SEIS prepared last April identifies numerous plant and animal species that may be present in the Wawona area, and might be adversely impacted by the housing project, neither this Biological Assessment, nor the Valley Plan SEIS, includes or otherwise provides documentation of the site-specific surveys and studies necessary to ascertain the presence of such species (and the housing project’s potential impacts thereon)." (Civic Organization, Wawona, CA - #7549)

Response: The Final Yosemite Valley Plan/SEIS addresses housing development impacts to plant and wildlife species, as well as other development and redevelopment impacts under the Vegetation, Wildlife, and Rare, Threatened, and Endangered Species sections in the Final Yosemite Valley Plan/SEIS (Chapter 4, Environmental Consequences). Methods used to evaluate potential effects of housing and other developments on these species are included in Vol. IB, Chapter 4. Impacts to vegetation and wildlife species documented in projects outside of Yosemite National Park, but in similar environments, were used to develop the impacts sections of the Final Yosemite Valley Plan/SEIS. Where available, site-specific surveys within these areas were also used to help evaluate impacts. Knowledge of specific species sensitivities were used to develop the mitigation guidelines (Vol. IA, Chapter 2) that would be used during any construction action, including avoidance, timing to avoid critical reproduction periods, site protection, and salvage and replanting and/or reintroduction. Additional compliance may be necessary during the design phase of any new development or redevelopment project.

466. Public Concern: The Yosemite Valley Plan should identify the presence of special status species at the proposed housing site in Wawona and detail plans to mitigate adverse impacts.

"The Biological Assessment discloses that the following special status species ‘have been found or could occur in Wawona:’ Cooper’s hawk, sharp-shinned hawk, long-eared owl, yellow warbler, willow flycatcher, golden eagle, peregrine falcon, bald eagle, harlequin duck, great grey owl, California spotted owl, special-status bats [listed elsewhere], western pond turtle, California red-legged frog, footless yellow-legged frog, mountain yellow-legged frog, Yosemite onion, snapdragon, Sierra sweet bay, Bolander’s skullcap, and giant sequoia. Neither the MRP FEIS nor the Valley Plan SEIS discloses whether any of these species are present at the site of the proposed housing project, nor addresses whether any of these species might be adversely impacted by this project. Nor do any of these documents explain what measures, if any, have been undertaken to ascertain whether any of these species are present or might otherwise be impacted by the housing project. This is a critical omission, since detailed survey protocols for many of these species require repeated surveys over several seasons, or even years, before sufficient data is developed to permit an informed evaluation of the possible presence of these species, and the potential impacts thereon of a proposed project." (Civic Organization, Wawona, CA - #7549)

Response: Although the list of rare, threatened, and endangered species that occur in Wawona is lengthy, only a portion of these species is expected to occur in the forested areas that could be developed under Alternatives 2 and 5 of the Final Yosemite Valley Plan/SEIS. While specific surveys for many special-status species are lacking, evaluation of potential impacts in this document assumes that if suitable habitat for a species occurs in an area, then the species is considered to be present. This conservative approach ensures that adequate consideration is given to rare, threatened, and endangered species. Such an analysis was conducted for Wawona; however, it was not clearly reflected in the Draft Yosemite Valley Plan/SEIS. This problem has been corrected in the Final Yosemite Valley Plan/SEIS. In addition, surveys for California spotted owls in Wawona and other areas of potential development in the park have been recently completed. Results of these surveys are included in the Final Yosemite Valley Plan/SEIS.

Most of the detailed evaluations of special status species would occur on a site-specific basis prior to implementation of the Final Yosemite Valley Plan/SEIS. This would provide the most up-to-date information on these species, allowing project planning that would minimize adverse effects on individual species. For example, although recent surveys revealed no California spotted owls in the proposed project area in Wawona, the area would need to be surveyed again before construction could begin, in case spotted owls had moved into that area in the meantime. Surveys for special status species would become an integral part of site planning and implementation of the Final Yosemite Valley Plan/SEIS.

545. Public Concern: The Yosemite Valley Plan should evaluate the cumulative impacts of increased human population in El Portal on wildlife.

"The DVP does not consider the related and cumulative impacts of increasing human population in El Portal, leading to impediment of wildlife from the riparian corridor on the north side of the river. Please note that the statement from the Draft VP ‘Expanses of north-facing habitat allow[s] unlimited access to the riparian zone for wildlife species’ is misleading. The expanses mentioned only allow access to individuals on that side of the river. Individuals on the development side will be further impeded and therefore impacted." (Conservation Organization, Yosemite, CA - #7883)

Response: A majority of development proposed for El Portal under the Preferred Alternative would occur in areas affected by existing development already, or areas with a history of disturbance. The existing dense development on the north side of the river (from the park boundary to El Portal Road), areas of disturbance further west at Rancheria Flat, and the National Park Service Maintenance/Warehouse and sewage treatment facilities are areas where greatest impacts to wildlife occur. In a regional, cumulative context, this development, coupled with the barriers of Highway 140 and, to a lesser extent, Foresta Road, relegate additional impacts that would result under the Yosemite Valley Plan to a relatively minor level.

Numerous factors were considered in evaluating impacts on wildlife as a result of proposed developments in the Final Yosemite Valley Plan/SEIS, in combination with existing development in the area (see Vol. IB, Chapter 4, Environmental Consequences—Wildlife).

629. Public Concern: The Yosemite Valley Plan should address the impacts of bridge removal on wildlife movement patterns.

"The SEIS also asserts that the removal of the bridges will have a beneficial impact on the wildlife habitat. However, I have personally observed deer and other wildlife utilizing the existing historic bridges to cross the Merced River. Therefore, elimination of the bridges may also result in significant adverse impacts to the movement of wildlife and result in more wildlife being injured as attempts are made to cross the few remaining auto and bus bridges that cross the Merced River. This impact was not addressed or analyzed in the SEIS." (Business, San Diego, CA - #7884)

Response: Some species of wildlife opportunistically use bridges for travel; however, this type of wildlife movement is unnatural and, therefore, should not be preserved. Wildlife in Yosemite Valley do not require the use of bridges to freely move from one section of the Valley to another. One of the focuses of the Yosemite Valley Plan is the restoration of natural processes, of which wildlife movements is a component. Removal of bridges, along with restoration of contiguous and linked habitats, would help restore natural movement of wildlife in Yosemite Valley.

561. Public Concern: The Yosemite Valley Plan should account for the potential effects of vehicle-induced pollution on aquatic species.

"Ironically, while replacing bridges along the Merced River to ostensibly improve the health of fish, as advocated in the plan, the proliferation of asphalt will negate the eco-advantages. A primary constituent of asphalt is petroleum. Recommended for reading is the report of the Alaska Fisheries Science Center, ‘Life-History Consequences of Oil Pollution in Fish Natal habitat.’ This report by scientists at the Auke Bay Laboratory of the Science Center concludes that the toxicity of oil pollution to aquatic populations has been seriously underestimated." (Individual, San Francisco, CA - #30241)

"Increasing human population in El Portal means increased non-point source pollution from parking lots, residential and working facilities, and vehicle deposits on road beds. This may adversely affect populations of aquatic insects, especially those that are sensitive to pollution, which may adversely affect bat, bird and fish populations." (Individual, El Portal, CA - #7026)

Response: As long as motor vehicles are allowed in Yosemite National Park, some low-level contaminated water runoff could affect aquatic environments. Actions prescribed under the Final Yosemite Valley Plan/SEIS, however, are designed to reduce the threat of pollution to aquatic habitats. Some roads and parking areas would be moved out of meadow and riparian areas and either replaced by facilities out of the Valley or in more upland areas in the Valley. Water runoff from parking facilities would be collected and treated to remove pollutants. Reduction in the number of cars coming into Yosemite Valley, as prescribed in the Final Yosemite Valley Plan/SEIS, would help reduce sources of vehicle-related pollution. Such changes would represent an improvement over the present situation.

Some actions proposed in the Final Yosemite Valley Plan/SEIS that prescribe increased development in El Portal could carry the increased risk of non-point pollution. The Final Yosemite Valley Plan/SEIS, however, provides specific actions and mitigation measures that would limit such risk to a negligible level. Development within 100 feet of the river would be limited by the River Protection Overlay. Runoff from parking lots and residential and working areas would be collected for treatment. Effluent from all new facilities in El Portal would be piped into the existing sewage treatment system. Facilities that carry an inherent risk of causing pollution (e.g., fueling facilities) would be designed to limit the chance of spills and provide adequate containment and treatment of potential spills. The largest benefit to water quality in El Portal under the action alternatives in the Final Yosemite Valley Plan/SEIS would be the removal of the commercial bulk fuel facility. This facility poses the greatest risk of both catastrophic spills and continual, low-level pollution from runoff into the river and adjacent wetlands, as well as seepage into groundwater.

104. Public Concern: The Yosemite Valley Plan should establish an intensive trout management program for the Merced River.

"In my judgment, there is no excuse for the disappearance of the trout from the Merced River in the Valley. This is simply a sign of poor management. An intensive stocking program should be instigated. Bait fishing could be allowed around the campgrounds with restricted size and number limits–say nothing under 6 inches and no more than 3 per day. To make it more sporting for the true angler, an area should be set aside for artificial flies and lures only–perhaps at the lower end of the Valley. The 6 inch size and 3 per day should also apply here. With persistent stocking of trout in the 6 plus inch size, and with stringent size and take regulations, there is no reason why the Valley cannot once again be a wonderful family fishing opportunity. This system has worked in many other places throughout the state. This would add so much to the Park and the resources are readily available to accomplish it. Under the present situation, the Merced River running through the Valley is simply being wasted as a marvelous family fishing resource and opportunity." (Individual, Laguna Niguel, CA - #387)

Response: This concern is acknowledged; however, it is outside the scope of the Yosemite Valley Plan. No actions proposed under the various alternatives would change current management practices. The intent of the Yosemite Valley Plan is to prescribe restoration and redevelopment, improve protection of park resources, and improve the quality of visitor experience in Yosemite Valley. Fishery management issues are addressed in the 1994 Resources Management Plan. Nonetheless, the Final Yosemite Valley Plan/SEIS would benefit fish populations in the Merced River by restoring riparian and meadow habitats.

The National park Service believes that a high quality, natural fishery can be provided in the Merced River by allowing natural river processes to occur, which would lead to rich and diverse fish habitats.

447. Public Concern: The Yosemite Valley Plan should account for potential effects of the proposed action on great grey owls.

"There is no discussion of the damage to great grey owl habitat from increasing traffic flow on the Old Coulterville Road." (Civic Organization, Foresta, CA - #7640)

"I have a concern about the adverse impact on great gray owls in Big Meadow of having the NPS stable at McCauley Ranch. An NPS stable at South Landing would probably be better for the great gray owl population than one at Foresta because of less proximity to a large meadow." (Individual, Columbia, CA - #7149)

Response: The slight increase in housing at Foresta, the relocation of concession and National Park Service stable operations to McCauley Ranch, and the possible establishment of a parking facility in Foresta would increase the amount of traffic through the area. Such traffic, however, is expected to have a minor to moderate effect on great gray owls. A vast majority of the habitat used by the owls in Big Meadow for wintering and staging (transiently used by owls migrating up from lower elevations) is well away from the road and proposed parking area, and traffic to the parking facility would not proceed beyond the area that is now the woodlot. Traffic associated with the stable and parking facility would primarily occur from late spring through early fall, when the owls would most often be at breeding areas in higher elevations. The National Park Service also recognizes that the parking facility could cause increased visitor use around Big Meadow, which could disturb the owls. Efforts will be made to manage visitor access to the meadow to protect the great gray owls that may still be in the area when the parking lot is in use. The small amount of housing that would be built in Foresta is expected to cause a minimal increase in traffic over the present level. Big Meadow was actively used by great gray owls before the 1990 fire, when there were over twice as many houses in Foresta than there would be under the actions considered in the Final Yosemite Valley Plan/SEIS.

623. Public Concern: The Yosemite Valley Plan should require an aggressive management plan to remove bear and deer populations from Yosemite National Park.

"As a long time visitor to Yosemite, I have watched the problem of bears and deer in the Valley, (and on some of the nearby hiking trails as well) grow to insufferable proportions. Not a tree can be planted without an ugly screen around it. The Valley is polluted at every turn with ugly bear-proof food lockers and one must even worry about a candy wrapper inadvertently left in a car, that might provoke a destructive bear attack. I have personal experience on the trails with bears destroying back packs, and threatening physical harm to children. All of this because of the misguided idea that ‘they were there first and have as much right to be there as we have.’ I have yet to see a bear, a deer, or even an elderberry long horned beetle or red-legged frog stand in wonderment at the beauty of El Capitan, or Mirror Lake. Bear and deer have no place in Yosemite Valley! They cannot be educated to conserve and preserve anything. There are plenty of places were they can and should be protected and allowed to roam, but not there. Because of its beauty, only humans who can truly appreciate it have a preemptive right to its beauty, only humans who can truly appreciate it have a preemptive right to unimpeded access to Yosemite Valley which supercedes the rights of any animal. I recommend the Park Service ignore the vociferous animal rights activists and uninformed nature lovers and begin immediately an aggressive program of judicious fencing to channel interlopers toward immediate capture and distant relocation along with appropriate negative learning experiences, to rid the Valley completely of bears, and most of the deer. This would go a long way toward restoring some of the flora which we are so concerned about. It would also cut down the gawking at a few deer in the meadows which cause traffic jams and people trampling vegetation chasing them around. Let people to go to other parks if they want to see wildlife." (Individual, Los Altos, CA - #3165)

Response: While management of wildlife falls outside the scope of the Yosemite Valley Plan, the National Park Service disagrees that human use of Yosemite National Park should be to the exclusion of some native wildlife species. Although conflicts between wildlife and humans occur in the park, management toward elimination of those conflicts through wide-scale removal of wildlife would be contradictory to the mission the National Park Service is charged to uphold. Such management would not only upset the ecology of Yosemite Valley, but also eliminate an important part of the visitor experience.

Section 4.7 ~ Air Quality

The effects of the proposed transportation plan on air quality in Yosemite National Park and upwind areas, some people contend, make it imperative that plans for Yosemite Valley stress air quality protection. Local pollution sources are perceived by many as a serious threat to the health of humans and the Valley ecosystem.

Given the importance of air quality protection, many respondents offer various suggestions for achieving this goal. One person recommends establishing air quality as an Outstandingly Remarkable Value on the El Portal section of the Merced Wild and Scenic River. Burgeoning development and diesel transportation systems, many predict, will contribute to air quality deterioration. Diesel fuel, they say, is a health hazard and its use is being phased out of many urban transportation systems. These respondents urge the same be done in Yosemite National Park.

People are also concerned with technical and administrative aspects of protecting air quality. Regulatory actions affecting Yosemite National Park, such as "the likely classification of Yosemite Valley as a nonattainment area for 8-hour ozone [levels]," one person says, require a discussion of regional issues and identification of mitigation measures within each of the alternatives. The complex nature of air quality data leads one person to ask that air quality statistics be conveyed clearly in language that the "non-scientific expert can understand." "The untenable conclusion that air quality and natural quiet are not significant," another advances, "are based on assumed results of a pilot test that has not yet occurred."

Concerned that the transportation plan may impact air quality, respondents ask that the National Park Service provide emissions data for all proposed transit vehicles. A vocal contingent protests the increased use of diesel buses for public transportation. "It doesn’t take a rocket scientist," one says, "to predict serious air quality problems." Another implies that the addition of diesel buses will also encroach upon visibility.

People question the adequacy of the analysis for air quality outcomes in the Draft Yosemite Valley Plan/SEIS. Because of the way air moves in the Valley, an individual challenges the sample site selected to make predictions. This person suggests that gasoline fuel be compared with diesel fuel in the analysis before the National Park Service selects an alternative. A respondent also suggests that the Final Yosemite Valley Plan/SEIS should include the percentages that each fuel source contributes rather than leaving, "informed decisions on air quality impacts . . . to emotion and anecdote."

People request further analysis of a variety of air pollution impacts. One respondent would like the final document to include information on the amount that motor vehicles contribute to ozone pollution in the Valley. Another would like an evaluation of health risks to Yosemite National Park visitors from airborne pollution and a description of provisions made to warn visitors of risks.

A commitment to using alternative fuels, many believe, would improve air quality in the Valley. "There has been no commitment," one citizen states, "or contractual agreement by YARTS to shift from diesel fueled buses to alternative fuel vehicles." The implementation timeframe for the plan allows plenty of time, according to one recreation organization, to explore "cleaner fuel alternatives."

Respondents ask that the impacts of air pollution on natural resources be addressed in the Final Yosemite Valley Plan/SEIS. Because air in the Valley flows up a "chimney" to the Lyell Fork of the Merced, one person suggests that "there may need to be changes in use patterns and fuel choices in order to protect the air quality of the designated wilderness." Several people are concerned that visible damage to ponderosa pines indicates a threat to vegetation from ozone pollution. They contend that the Final Yosemite Valley Plan/SEIS should specifically address ozone impacts on vegetation.

A number of people believe that campfire and cigarette smoke deteriorate air quality and pose a threat to human health. Valley campfires, respondents demand, should be prohibited to help remedy this problem. Some go even further, suggesting the Yosemite Valley Plan should also prohibit smoking in the park.

74. Public Concern: The Yosemite Valley Plan should emphasize air quality protection in Yosemite Valley.

"If Air Quality is not expressly stated in the Merced River Plan, it can legally be ignored in subsumed plans such as the Yosemite Valley Plan. Finally, by including Air Quality in the MRP and the YVP, the Park can use this mandate to help clean up upwind sources of pollutants that affect the Park. . . It could use this authority to impose on upwind sources of air pollution outside the Park to clean up the air that blows into the Park." (University of California, Department of Environmental Science, Policy, and Management, Berkeley, CA - #138)

"The Park should take every measure to curb local pollution sources in the Valley for the health of the visitors that come to enjoy the pristine nature of the Park, and for the diversity of sensitive plants and animals which live in the Park." (Department of Environmental Science, Policy and Management, University of California, Berkeley, CA - #138)

ESTABLISH AIR QUALITY AS AN OUTSTANDINGLY REMARKABLE VALUE

"Clean air quality should also be included as an ORV for the El Portal section of the Merced WSR. Air quality will be adversely impacted by residential emissions from homes and automobiles due to the doubling of the residential human population. Air quality will also be impacted by the use of a diesel bus shuttle system for employees. Environmental impacts from diesel are hazardous. Diesel is being legally outlawed and phased out of cities such as New York. The NRDC has won several cases condemning diesel bus emissions for adversely impacting public health." (Individual, El Portal, CA - #7026)

Response: Air quality protection for Yosemite Valley and the rest of the park is very important because the area is affected by downwind sources in the San Joaquin Valley. Although air quality protection is not expressly stated in the Merced River Plan/FEIS, the National Environmental Policy Act (NEPA) requires that resources such as air quality and related values be included in the NEPA analysis. Both the Merced River Plan/FEIS and the Final Yosemite Valley Plan/SEIS meet this requirement by fully disclosing the current air quality conditions in the park and identifying potential air quality impacts of each alternative (see the Air Quality sections in Vol. IA, Chapter 3 and Vol. IB, Chapter 4). The inclusion of air quality in these two documents does not give the park authority to impose its mandate on sources of air pollution outside the park. The Federal Clean Air Act and its amendments and the California Clean Air Act provide legal guidance to control air pollution sources inside and outside the park. However, as a Class I airshed, Yosemite National Park has an important mandate to participate in decision making on new or modified air pollution source plans in the vicinity off the park.

454. Public Concern: The Yosemite Valley Plan should include a discussion of regional air quality issues and mitigation measures under all alternatives.

"Air quality is also an issue outside the Park boundaries for the regional air basin that includes Mariposa County, Tuolumne County and Yosemite National Park. This air basin will likely be classified in the near future as a non-attainment area for 8-hour ozone (O3). Please include a discussion of the regional air quality issues and the mitigation that would be involved with all the Plan’s alternatives." (Governor’s Office on Planning and Research, Sacramento, CA - #6584)

Response: The California Air Resources Board and local air districts are responsible for developing clean air plans or State Implementation Plans to demonstrate how and when California will attain air quality standards established under both the federal and California Clean Air Acts. For the areas within California that have not attained air quality standards, the Air Resources Board works with air districts to develop and implement state and local attainment plans. In general, attainment plans contain a discussion of ambient air quality data and trends; a baseline emissions inventory; future year projections of emissions, which account for growth projections and already adopted control measures; a comprehensive control strategy of additional measures needed to reach attainment; an attainment demonstration, which generally involves complex modeling; and contingency measures. Many of California's State Implementation Plans rely on the same core set of control strategies, including emission standards for cars and heavy trucks, fuel regulations, and limits on emissions from consumer products. State law makes the Air Resources Board the lead agency for all purposes related to the State Implementation Plans. Local air districts and other agencies prepare State Implementation Plan elements and submit them to the Air Resources Board for review and approval, and the Air Resources Board forwards State Implementation Plan revisions to the U.S. Environmental Protection Agency for approval.

The National Park Service is active in its role as a federal land manager and makes recommendations to the U.S. Environmental Protection Agency and the California Air Resources Board regarding protection of air quality and related values in Yosemite National Park, which is a Class I airshed. The National Park Service also works with the local air quality districts during the State Implementation Plan process and in the review of New Source Review applications. If surrounding counties achieve nonattainment status, the National Park Service would be involved in conformity determinations as well. In this context, the National Park Service would work to protect the air quality of Yosemite National Park with the intent of also benefiting surrounding areas.

195. Public Concern: The Yosemite Valley Plan should include clear documentation supporting air quality findings regarding Yosemite Valley.

"The NPS preferred Alternative 2 indicates air emissions in tons of pollution each year in a chart that is difficult to comprehend. It is a compilation of numbers that does not appear to be conclusively supported by data. Can this pollution information be conveyed more clearly? Can someone explain what this means in a way that the average, non-scientific expert can understand? Please provide the data that supports the stated information." (Individual, Malibu, CA - #1164)

PROVIDE DOCUMENTATION SUPPORTING DETERMINATION OF OUTSTANDINGLY REMARKABLE VALUES

"Where is the data, and where are the studies which demonstrate that appropriate science-based research was employed to determine all aspects of the Outstanding Remarkable Values? Mere repetition of a false assumption does not make it true . . . These issues are central to diesel bus pollution. Based on modeling, the Park Service and BRW, Inc., have incorporated the untenable conclusion that air quality and natural quiet are not significant. This conclusion permits an unproven and untested busing operation for mass transportation. The Valley Plan transportation elements are based on assumed results of a pilot test that has not yet occurred." (Individual, Malibu, CA - #1164)

Response: The data provided in the tables in the air quality sections of Vol. IB, Chapter 4, Environmental Consequences, in the Final Yosemite Valley Plan/SEIS are the summary results of the modeling and analysis that are described in the Methodologies and Assumptions section in Chapter 4 and in Vol. II, Appendix I, Air Quality Data. Also in Chapter 4 is a comparative description of these data in relation to the No Action Alternative (Alternative 1). The conclusion of each potential air quality impact further delineates the type (i.e., beneficial or adverse) and intensity of the impact. Appendix I provides more supporting details on the ambient air dispersion modeling for carbon monoxide and PM₁₀(particulate matter less than 10 microns) ambient air quality levels that was used in the air quality analysis.
(Also see response to concern #318.)

318. Public Concern: The Yosemite Valley Plan should include detailed information regarding transit vehicle emission factors.

"What I’d like is some specific information on the visitor transit vehicles operated by YCS, whether government or YCS-owned, and the emissions factors used for these and other vehicles to estimate annual air emissions in the Valley Plan for 2000, 2005, 2015 for Alternative 1-No Action and Alternatives 2-5." (Individual, Citrus Heights, CA - #2360)

Response: See Vol. II, Appendix I, Air Quality Data, in the Final Yosemite Valley Plan/SEIS for a description of air quality modeling used in air quality analysis for this document. Emission factors are a function of many variables, including vehicle speeds, vehicle types, vehicle technology mix, and meteorology. The gasoline and diesel emission factors generated by the California Air Resources Board model titled "EMFAC version 7G" are composite values that represent a mixed fleet of automobiles, trucks, and buses. Summary documents specific to air quality analyses, including emission factors, are available in the Yosemite Research Library. Because no emission factor data is available for the transit buses that currently operate in the Valley, the default values of EMFAC were used to estimate current and future emissions. The data used in the Final Yosemite Valley Plan/SEIS fill over 700 pages of spreadsheets. The emission factor raw data is voluminous and not easily summarized. The air emission results presented in the Final Yosemite Valley Plan/SEIS are most usable if viewed from a comparative basis rather than an absolute basis. From this comparative perspective, the reader can make a judgement on the benefits or drawbacks of the alternatives compared to the No Action Alternative.

92. Public Concern: The Yosemite Valley Plan should address potential increased diesel emission impacts in Yosemite Valley under proposed actions.

"The Plan calls for over 200 more diesel bus trips into the valley every day - pouring out substantially greater pollution than gasoline engines into a laterally enclosed valley. It doesn’t take a rocket scientist to predict serious air quality problems as per the L.A. Basin, Santa Clara and Livermore Valleys." (Individual, Richmond, CA - #373)

"Over 40 chemicals in diesel exhaust are considered toxic air contaminants and have been determined by the federal and state EPA to be carcinogenic. . . As currently conceived, in the real world this shift in transportation would serve to make toxic air emissions, noise and visual pollution even worse. Yosemite is a Class I Area under the Clean Air Act. The intention of this is a non-degradation policy for visibility and air quality. The addition of diesel buses will further encroach on these values." (Individual, No Address - #7337)

Response: Each of the action alternatives in the Final Yosemite Valley Plan/SEIS seeks to accommodate visitor travel needs at varying levels while protecting natural resources such as air quality and natural soundscapes. The availability of proven transit vehicle technology, supporting infrastructure, such as refueling and maintenance facilities, environmental characteristics (including noise levels and air emissions), and costs are all major factors in decisions related to transit vehicle selections.

The additional shuttle buses planned for all the action alternatives would displace numerous visitor private vehicles and the air emissions that they generate. The air emissions analyses in the air quality sections in Vol. IB, Chapter 4, which include the emissions from shuttle buses, indicates that there would be a beneficial impact on all emissions except nitrogen oxide emissions in all the action alternatives if diesel buses meeting existing emissions standards were used. The analysis also documents the emission impacts of alternative-fueled buses.

The park is a Class I area and is actively working with state and local governments to reduce regional emission that could impact Yosemite. In addition to working to improve regional air quality, the National Park Service is seeking to improve local air quality by aggressively pursuing cleanest available technology when considering future bus purchases. Moreover, the park is working with local, regional, and state transportation agencies on measures that would improve transportation-related air emission, including those from diesel buses.

75. Public Concern: The Yosemite Valley Plan should include a comparative analysis of gasoline and alternative fuels emission impacts on Yosemite Valley.

INCLUDE REPRESENTATIVE RANGE OF SAMPLE SITES

"Comparisons between alternatives were based on one stretch of road, between Sentinel Bridge and Yosemite Lodge on the north side of the Valley, considered the ‘worst case scenario’ piece of road in the Valley. However, the use of this particular piece of road is entirely responsible for the different Air Quality outcomes of the Alternatives because of the relation between the locations of this road, Taft Toe, and other major parking areas. For example, it makes the Taft Toe Alternatives (3,4) look better because traffic would then not pass through this particular stretch of road. However, air pollution knows no such area restrictions. Air pollution from parking and traffic at Taft Toe will diffuse to all parts of the Valley and would be no different than air pollution at Yosemite Lodge and Curry Village. This is a poor way to have compared plans and it manipulates the results to appear different than they would actually be." (University of California, Department of Environmental Science, Policy, and Management, Berkeley, CA - #138)

INCLUDE EVALUATION OF SWITCHING FROM GASOLINE TO ALTERNATIVE FUELS

"Comparisons were made on the basis of emissions from certain fuel types: diesel, CNG propane and fuel cells. . . Why was there no consideration of the emissions from the most common fuel type of the 6000 cars that visit the Valley daily during peak season: Gasoline? And why was there no discussion of the effect [of] simply implementing new fuel technologies in Alternative 1, which must certainly be the plan for the status quo? I believe it probably makes the other alternatives look better. I believe that the status quo might actually look the best if such comparison were made." (University of California, Department of Environmental Science, Policy, and Management, Berkeley, CA - #138)

Response: Emissions from gasoline-powered vehicles (both visitor and park service) that enter the Valley during the peak season are included in the emission totals for all alternatives and for all years. The column subheadings Diesel, Compressed Natural Gas (CNG), Propane, and Fuel Cell (FC) that are in the tables documenting emissions forecasts in Vol. IB, Chapter 4, Environmental Consequences, refer to the type of fuel technology that was assumed in each scenario for the in-Valley and out-of-Valley shuttle bus fleets operating in the Valley.

The effect of newer vehicles with improved emission control systems replacing older vehicles over time is reflected in the latter years for all alternatives on the same basis. This is an inherent feature of the Emission Factor (EMFAC) model and was not altered for any alternative. The use of alternative fuel/propulsion technologies for the shuttle bus fleet was not considered in the No Action Alternative because implementing these fuels would require the construction of new facilities (e.g., fueling stations) that could not be constructed without conducting environmental compliance procedures.

620. Public Concern: The Yosemite Valley Plan should include an analysis of the percentage contribution of each air pollution source.

"I believe it would be useful for the decision process if there was a study, perhaps ongoing, of the sources and percentage contribution of each air pollution source and component. That sort of approach has certainly proved enlightening with regard to snowmobiles in Yellowstone. Attacking high profile but ultimately marginal sources would divert energy and resources from more productive efforts and without an understanding of the air emission budget of the Valley informed decisions on air quality impacts are left to emotion and anecdote. Are automobiles still the main problem after thirty years of emission control or are effectively unregulated diesel buses, both park concessionaire and package tour, contributing more to compromise Yosemite air quality?" (Individual West Chester, PA - #6411)

Response: Existing sources of air pollution within the Valley are summarized in Vol. IA, Chapter 3, Affected Environment, of the Final Yosemite Valley Plan/SEIS, in the table titled "1998 Estimated Air Emissions in Yosemite Valley." The table includes stationary sources, such as heating equipment, generators, fireplaces, and fuel storage tanks; area sources, such as campfires; and mobile sources, such as automobiles and buses. Although the data presented in the table are in tons per year for each criteria pollutant, percentages are readily calculated. Also, although emissions from automobiles and buses are not broken out in the table, a review of the data indicates that automobiles are the largest source of air pollution in the Valley.

621. Public Concern: The Yosemite Valley Plan should include an analysis of motor vehicle contributions to ozone pollution.

"The improvements made in air quality in all the alternatives in relation to Alternative 1, the status quo, have entirely to do with several very faulty ways of representing the data. This is appalling to me. First, all alternative comparisons were made on VOC, CO, NOx, SO4, and PM10. Why was there no discussion of one of the primary pollutants in the Park for which the Park is already out of attainment at the National Level: Ozone?. . . While much ozone comes from outside the Valley, the 6000 cars and 63 buses on average that visit the Valley daily during peak season contribute to the ozone problem in the Valley." (University of California, Department of Environmental Science, Policy and Management, Berkeley, CA - #138)

Response: The Final Yosemite Valley Plan/SEIS contains an analysis of air pollutants generated in Yosemite Valley from visitor, park, and concessioner vehicles for each of the alternatives. Although cars, buses, and other vehicles operating in the park do contribute to the ozone problem, they do not emit ozone directly. Ozone is a reactive photochemical pollutant formed when volatile organic compounds and compounds of nitrogen oxide are emitted into the atmosphere and react with sunlight. This is why the alternative comparisons were made on the basis of the pollutants that are generated directly by vehicles. These include volatile organic compounds, carbon monoxide, compounds of nitrogen oxide, sulfur dioxide, and particulate matter under 10 microns emissions. Analogous emissions associated with construction proposed in the action Alternatives also were calculated for comparative purposes. The major source of particulates in the Valley is the road dust generated by vehicles. Particulates also are generated by diesel exhaust from tour buses and Valley shuttles, and these are included in the tables presented in the air quality impact analyses in Vol. IB, Chapter 4.

197. Public Concern: The Yosemite Valley Plan should include an analysis of health risks to Yosemite National Park visitors resulting from diesel emission exposure.

"In the Valley, campers will be most exposed to the effects of carcinogenic diesel. Please calculate the level of carcinogenic risk and exposure to campers who will camp for two weeks in the Valley." (Individual, Malibu, CA - #1164)

Response: Over the 15-year period considered in the air quality analysis in the Final Yosemite Valley Plan/SEIS, any of the action alternatives would reduce air emissions generated in Yosemite National Park, which should result in corresponding improvements in air quality. Ozone and particulate matter are monitored in the Valley, and although they have exceeded state standards several times in recent years, they have not exceeded national standards for these same time periods. The air quality analysis presented in the Draft and Final Yosemite Valley Plan/SEIS indicated that there would be a negligible increase (less than 1%) in nitrogen oxide emission generation by 2015 for the Preferred Alternative compared to the No Action Alternative, while the other vehicle pollutants, including particulate matter from vehicles, would decline. The Final Yosemite Valley Plan/SEIS analysis of one congested road segment in the Valley indicated that one-hour average particulate matter and carbon monoxide ambient air levels would actually decrease 30% to 50% for the Preferred Alternative by 2015 compared to the No Action Alternative. These analysis results do not indicate that health risks to visitors and employees would increase.

196. Public Concern: The Yosemite Valley Plan should include measures to inform the public of potential health threats resulting from vehicle emissions in Yosemite Valley.

"How will visitors be warned of [the] carcinogenic nature of the pollution created in the Valley by this transportation system? Will the NPS be posting signs in highly visible locations all throughout the Park, the Valley, along transportation routes and at all bus transit stations and facilities where people will load and unload so that the public is adequately informed as required by law? What are the cumulative impacts to public health and safety?" (Individual, Malibu, CA - #1164)

Response: Ozone and particulate matter are monitored in the park, and although they have exceeded state standards several times in recent years, they have not exceeded national standards for these same time periods. The air quality analysis presented in the Draft and Final Yosemite Valley Plan/SEIS indicated that there would be a negligible increase (less than 1%) in compounds of nitrogen oxide emission generation by 2015 for the Preferred Alternative compared to the No Action Alternative, while the other vehicle pollutants, including particulate matter from vehicles, would decline. The Yosemite Valley Plan analysis of one congested road segment in the Valley indicated that one-hour average particulate matter and carbon monoxide ambient air levels would actually decrease 30% to 50% for the Preferred Alternative by 2015 compared to the No Action Alternative. These results do not indicate that health risks to visitors and employees would increase.

717. Public Concern: The National Park Service should demonstrate its commitment to the use of alternative fuel vehicles in the Yosemite Valley Plan.

"In Volume III, page III-14 there is the statement ‘The National Park Service in Yosemite is committed to the use of alternative fuel vehicles, and to assuring that conventional combustion vehicles are functioning to minimize potential air quality impacts.’ This was in response to a public comment on air quality. This ‘commitment’ is not mentioned on page 2-150; nor is there any suggestion of a timetable or protocol to achieve this commitment. Instead, the document reads: ‘Apply best available clean fuel technology as it becomes available, to the extent feasible. . . There has been no commitment or contractual agreement by YARTS to shift from diesel fueled buses to alternative fueled vehicles. This . . . makes the assumption for the Action Alternatives totally inappropriate." (Conservation Organization, Mariposa, CA - #9224)

"The Park should continue to explore with great passion within that 15-year timeframe cleaner fuel alternatives, as suggested in Chapter 2-23, Mitigation measures common to all Action alternatives. Harmful emissions from diesel buses will continue to contribute to a reduction in visibility that already obscures the towering rock formations that rise from the valley floor." (Recreation Organization, Silver Spring, MD - #10092)

Response: The Preferred Alternative in the Final Yosemite Valley Plan/SEIS states that the National Park Service would consider low noise, low emissions, cost-effectiveness, and the use of alternative fuels as the primary criteria for acquiring in-Valley and out-of-Valley shuttle bus fleets.

The National Park Service is currently moving toward the use of the most clean and quiet transit vehicles feasible in the Valley, and has committed in Vol. IA, Chapter 1 of the Final Yosemite Valley Plan/SEIS to continue strategies to implement technologies that reduce mobile sources of air pollution.

598. Public Concern: The National Park Service should analyze the impacts of air pollution in Yosemite Valley on the Yosemite Wilderness.

"If the wilderness up around the Lyell Fork of the Merced is at the top of a ‘chimney’ leading from Yosemite Valley and [there are] all those tons of burning fake logs and diesel fuel, there may need to be changes in use patterns and fuel choices in order to protect the air quality of the designated wilderness." (Individual, West Chester, PA - #6411)

Response: Yosemite National Park’s mandate is one of environmental protection, and each of the action alternatives in the Final Yosemite Valley Plan/SEIS proposes to limit impacts on resources, including air quality, from internal park operations and visitor use. For example, the Preferred Alternative proposes measures to reduce visitor vehicle traffic and associated air emissions in the Valley relative to existing conditions. The park is using sustainable design and development techniques for future buildings and operations in the park where feasible to achieve reductions in park emissions and energy consumption.

There are numerous air quality monitoring stations in and near the park that analyze both gaseous and particulate pollutants. For example, monitors in the park include an ozone monitor along with an Interagency Monitoring of Protected Visual Environments site at Turtleback Dome, and a particulate monitor at the park headquarters near the visitor center in Yosemite Valley. The park has also been involved in biological effects research and monitoring related to air pollution for many years. Research has determined that ponderosa and Jeffrey pine trees, two key species in Yosemite National Park, are highly sensitive to tropospheric ozone. The park currently monitors both species for early detection of change.

93. Public Concern: The Yosemite Valley Plan should address air pollution impacts on vegetation in Yosemite Valley.

"Although not enforced by law, air quality standards to protect vegetation are even lower than those for people. . . The protection of trees, wildflowers, shrubs and grasses within Yosemite Valley should provide substantial incentive to improve air quality. Ponderosa pine are the most sensitive tree in the Sierra to ozone damage. In terms of vegetation injury and human health concerns, they can be considered the canary in the coal mine. . . Although the results of ozone damage studies on the Valley floor are presently unavailable, ozone damage has been observed on ponderosa and the less sensitive Jeffrey pine throughout the Park." (University of California, Department of Environmental Science, Policy, and Management, Berkeley, CA - #138)

"A third of conifers in Yosemite below 6,000 feet in elevation are seriously damaged, dying or dead due to air pollution, this aspect should be of utmost importance in any consideration of Yosemite’s future." (Individual, San Francisco, CA - #30241)

Response: The National Park Service is aware of its responsibility to curb air pollution sources within Yosemite National Park to protect not only visitor and employee health but also welfare or non-health values, such as visibility, vegetation, and wildlife. In order to monitor ozone trends in the Valley, the park has operated an ozone monitor at Turtleback Dome for more than a decade. The park has been involved in biological effects research and monitoring related to air pollution for many years. Research has determined that ponderosa and Jeffrey pine trees, two key species in Yosemite National Park, are highly sensitive to tropospheric ozone. The park currently monitors both species for early detection of change.

The Final Yosemite Valley Plan/SEIS also acknowledges that the California Environmental Protection Agency concluded that the ozone exceedances in 1995 in the southern portion of the Mountain Counties Air Basin, which includes Mariposa County, were caused by transport of ozone and ozone precursors from the San Joaquin Air Basin. The park’s mandate is one of environmental protection, and its goal is to limit impacts to natural resources, including air quality and vegetation, from park operations and visitor use.

716. Public Concern: The Yosemite Valley Plan should identify campfire smoke as a source of air pollution.

"The SEIS fails to consider campfire smoke as an identifiable point source of air pollution. The only sources considered were vehicles, construction and demolition activities. As can be seen on any evening in the Valley, significant air quality impacts are created by the hundreds of individual campfires permitted in the campgrounds. This impact must be included in the evaluation of alternatives. Clearly an alternative with fewer campsites and thus fewer campfires has a beneficial effect compared to the current situation." (Individual, Union City, CA - #4404)

Response: In Vol. IA, Chapter 3, Affected Environment, Air Quality, in the Draft Yosemite Valley Plan/SEIS, campfires were identified as sources of particulate matter, carbon monoxide, and volatile organic compounds in the Valley. There are currently 475 campsites in the Valley, and under Alternative 2 (Preferred Alternative) in the Final Yosemite Valley Plan/SEIS, the number would increase by approximately 5% to 500 campsites. Alternatives 3 and 4 would reduce the number of sites to 450 and 441, respectively, while Alternative 5 increases campsites to 585. The park has recognized that campfires make significant contributions to air pollution in the Valley and has taken measures to reduce their impact. For example, campfires are permitted only from 5:00 p.m. until 10:00 p.m. from May 1 to October 15, and campfires are permitted only in established fire rings. Collection of firewood, including "dead and down" wood, is prohibited in the Valley, as is cutting live or dead trees and attached limbs. These rules are widely disseminated to park visitors through the park’s free quarterly newspaper (Yosemite Guide), web site (www.nps.gov/yose/), and other media.

506. Public Concern: The National Park Service should ban smoking within Yosemite National Park.

"Ban smoking within the Park (or allow it only in designated areas adequately separated from others). Some of the worst air pollution visitors actually experience in Yosemite comes from smokers (especially employees). At least ban smoking from prime places such as Glacier Point." (Individual, Los Altos, CA - #20564)

Response: This concern is acknowledged; however, it is outside the scope of the Yosemite Valley Plan.

758. Public Concern: The Yosemite Valley Plan should commit to pollution prevention practices for shuttle bus fleet maintenance.

"Alternative 2, the preferred alternative, estimates the need for 74 shuttle buses to provide both in-Valley and out-for-Valley shuttle bus service. The SEIS does not provide detail on fleet maintenance. Recommendation: In the Final EIS commit to pollution prevention practices for fleet maintenance. (Environmental Protection Agency, San Francisco, CA - #10295"

Response: This concern is acknowledged, and Vol. IA, Chapter 2 Alternatives, Mitigation Measures, of the Final Yosemite Valley Plan/SEIS includes a requirement for the use of pollution prevention practices for maintenance and operations of the shuttle bus fleet prescribed by the Yosemite Valley Plan. After the shuttle bus maintenance facilities prescribed in the Yosemite Valley Plan are operational, shuttle bus operations and maintenance will be required to comply with the Yosemite National Park Pollution Prevention Control Program and the Hazardous Waste Minimization Plan. This program meets the guidelines prescribed by the Environmental Protection Agency