Bureau of Reclamation: An Assessment of the Environmental Impact Statement on the Operations of the Glen Canyon Dam
Released: 1996-10-02T00:00:00

Letter

Introduction

The Glen Canyon Dam was completed by the Bureau of Reclamation in 1963 as a multipurpose facility. It is the key feature and major storage unit of the Colorado River Storage Project. The Colorado River Storage Project was authorized in 1956 to develop and use the water resources in the Upper Colorado River Basin. The operations of the Glen Canyon Dam and its reservoir, Lake Powell, enable the Colorado River Storage Project to fulfill the downstream water release requirements while the runoff from the Upper Basin is stored and used for irrigation, recreation, and municipal and industrial purposes.

The powerplant at the Glen Canyon Dam has been used primarily for generating power during high-demand periods (peaking power). The fluctuating releases of water associated with peaking power operations have caused concern among federal, state, and tribal resource management agencies; river users who fish in Glen Canyon or take white-water raft trips in the Grand Canyon; and Native American and environmental groups, in connection with the detrimental effects that such water releases have on the cultural resources and the downstream plants, animals, and their habitats.

Operation of the Glen Canyon Dam’s Powerplant

The Glen Canyon Dam powerplant has eight generators with a maximum combined capacity of 1,288,000 kilowatts at a 95-percent power factor. The maximum combined discharge capacity of the eight turbines is approximately 33,200 cubic feet per second (cfs) when Lake Powell is full; however, Reclamation has limited such releases to 31,500 cfs. Fluctuations within a day have typically ranged from 12,000 cfs in October to about 16,000 cfs in January and August. Although water can be released from the dam through the powerplant, the outlet works, or the spillways, discharging water through the powerplant’s turbines is the preferred method because electricity and its associated revenue can be produced. The power generated by the Glen Canyon Dam is marketed principally in a six-state area—Arizona, Colorado, Nevada, New Mexico, Utah, and Wyoming. Figure 1.1 shows the various release capacities for the Glen Canyon Dam.

Historically, the Glen Canyon Dam, as part of the Colorado River Storage Project, was operated to produce the greatest amount of firm capacity and energy practicable while adhering to the releases required under the “Law of the River.” The Law of the River—a collection of federal and state statutes, compacts, court decisions and decrees, federal contracts, a treaty with Mexico, and formally determined long-range operating criteria—defines the operation and management of the Colorado River. The operating criteria for the dam were established under the “Criteria for Coordinated Long-Range Operation of Colorado River Reservoirs” (Long-Range Operating Criteria), which include the criteria for annual operations. The Annual Operating Plan, which is prepared under the Long-Range Operating Criteria, addresses monthly operations while interagency agreements control the dam’s hourly operations.

The annual volume of releases from the dam is based on the water inflow to Lake Powell and the remaining space in Lake Powell and Lake Mead. The annual release volumes vary greatly, but all adhere to the Long-Range Operating Criteria’s objectives of an 8.23-million-acre-feet minimum annual release and equalized storage between the two reservoirs. From 1968 to 1989, the annual releases ranged from 8.23 million acre-feet to 20.4 million acre-feet. Annual releases greater than the minimum were permitted to avoid anticipated spills (excess annual releases that cannot be used for project purposes) and to equalize storage. The minimum release occurred in about half the years.

The volume of water released from Lake Powell each month depends on the forecasted inflow, existing storage level, monthly storage targets, and annual release requirements. Demands for electrical energy, fish and wildlife needs, and recreation needs are also considered and accommodated as long as the risk of spilling and storage equalization between Lakes Powell and Mead are not affected. Power demand is highest during the winter and summer months, and recreation needs are highest during the summer. Therefore, higher-volume releases are scheduled during these months whenever possible. Each month during the inflow forecast season (January to July), the volume of water to be released for the rest of the year is recomputed on the basis of updated streamflow forecast information. The Scheduled releases for the remaining months are adjusted to avoid anticipated spills and maintain conservation storage in accordance with the Long-Range Operating Criteria.

Hourly releases from the dam are set to reach monthly release volumes, to maintain established minimum flow rates, and to follow energy demand. Hourly power operations are most flexible during those months with moderate release volumes. The need to maintain minimum flows in the months with low release volumes limits the flexibility to accommodate changing hourly power demands. If the reservoir is nearly full and the inflow is extremely high, the monthly releases are scheduled at or near the maximum capacity most of the time, again leaving little flexibility for the hourly releases to change in response to power demand.

To the extent possible, the Glen Canyon Dam follows these guidelines in producing hydropower: • Maximize water releases during the peak energy demand periods, generally Monday through Saturday between 7 a.m. and 11 p.m., • Maximize water releases during peak energy demand months and minimize during low demand months, • Minimize and, to the extent possible, eliminate powerplant bypasses.

Glen Canyon’s Environmental Studies and Environmental Impact Statement

Before the construction of the Glen Canyon Dam, the Colorado River’s sediment-laden flows fluctuated dramatically during different seasons of the year. Flows of greater than 80,000 cfs were common during the spring runoff. In contrast, flows of less than 3,000 cfs were typical throughout the late summer, fall, and winter. Water temperatures ranged from near freezing in the winter to more than 80 degrees Fahrenheit in the summer. The construction of the Glen Canyon Dam altered the natural dynamics of the Colorado River. The dam replaced seasonal flow variations with daily fluctuations, greatly reduced the amount of sediment in the river, and resulted in nearly constant water release temperatures of about 46 degrees Fahrenheit.

In response to the concerns of federal, state, and tribal agencies and the public about the negative effects of the dam’s operations, in December 1982 the Secretary of the Interior directed Reclamation to initiate a series of interagency scientific studies. These studies were to examine the short- and long-term effects of the dam’s historic, current, and alternative operations on the environmental and recreational resources of the Glen and Grand canyons. The studies became known as phase I of the Glen Canyon Environmental Studies. From 1982 through 1987, 39 technical reports were prepared evaluating terrestrial biology, aquatic biology, sediment and hydrology, recreation, and the dam’s operations. However, no studies were conducted on the economic impact to hydropower from changes in the dam’s operations. According to Reclamation, of primary importance in the Glen Canyon Environmental Studies was the research connected with endangered fish. The existence and operations of the dam were believed to be important factors involved in the extinction of two fish species (the Colorado squawfish and bonytails) from the river corridor. The dam and its operations were also considered to present survival problems for the existing populations of the humpback chub and razorback sucker as well as other native fish species. Therefore, according to Reclamation, the biological opinion issued by the U.S. Fish and Wildlife Service in 1994 was an important factor in the ultimate formulation of the preferred alternative in the environmental impact statement (EIS).

The Glen Canyon Environmental Studies technical reports were concurrently reviewed by the National Research Council and the Executive Review Committee. The Executive Review Committee was made up of policy-level representatives from Reclamation, the National Park Service, the U.S. Fish and Wildlife Service, the Department of the Interior’s Office of Environmental Policy and Compliance, and the Western Area Power Administration. This Committee then prepared a report in January 1988 on the findings and conclusions of phase I of the Glen Canyon Environmental Studies and made recommendations and suggested options for revising the dam’s operations.

In June 1988, phase II of the Glen Canyon Environmental Studies was initiated to gather additional data over a 4- to 5-year period on the dam’s specific operational elements. Phase II was to further define the impacts on the natural environment, public uses associated with recreation, cultural resources, and power-generation economics. At the urging of the National Research Council, an entity of the National Academy of Sciences, non-use values were incorporated into the studies. “Non-use value” is the term used to describe the monetary value that non-users place on the status of the environment. For example, the values that people may receive from the knowledge that such things as rare plants, animals, and unspoiled natural environments exist are defined as non-use values. A number of federal and state resource agencies, Indian tribes, private consultants, universities, and river guides participated in phase II of the Glen Canyon Environmental Studies. Funding for these studies was provided mainly from the revenue derived from the sale of electricity generated by the Glen Canyon Dam.

In July 1989, the Secretary of the Interior decided that Reclamation should prepare an environmental impact statement to reevaluate the operations of the Glen Canyon Dam. The purpose of the EIS was to determine specific options for operating the dam that could minimize the adverse impacts on the downstream environmental and cultural resources, as well as on the Native American interests in the Glen and Grand canyons, while still producing hydropower. Reclamation was designated by the Secretary to be the lead agency responsible for preparing the EIS; other participants were the following cooperating agencies: the Bureau of Indian Affairs, the National Park Service, the U.S. Fish and Wildlife Service, the Western Area Power Administration, and the Arizona Game and Fish Department. In 1989, after the EIS process started, Reclamation also made the following Native American tribes cooperating agencies: the Hopi Tribe, the Hualapai Tribe, the Navajo Nation, the Pueblo of Zuni, the San Juan Southern Paiute Tribe, and the Southern Paiute Consortium. Officials from many of these same agencies and tribes participated in the Glen Canyon Environmental Studies, which formed the basis for the analyses of alternatives for the EIS.

Calif.

The requirement to prepare an EIS accelerated the scheduled completion of the research studies in phase II of the Glen Canyon Environmental Studies to provide more timely data for the EIS. This acceleration was accomplished by designing special “research flows,” a series of carefully designed discharges of water and data collection programs conducted in June 1990 through July 1991. Each research flow lasted 14 days and included 3 days of steady 5,000 cfs flows and 11 days of either steady or fluctuating flows. The research flows provided a means to evaluate the short-term responses of certain resources to a variety of discharge parameters, including minimum and maximum flows, the rate of change in flow, and the range of daily fluctuations.

To protect downstream resources until the completion of the EIS and the formal adoption of new operating criteria for the Glen Canyon Dam, Reclamation implemented the interim dam operations on November 1, 1991. The interim operating criteria were purposely designed to be conservative for the protection of natural and cultural resources. Specifically, the interim criteria reduced peak water releases from the approved maximum of 31,500 cfs to 20,000 cfs; restricted daily fluctuations in releases to between 5,000 cfs and 8,000 cfs; and restricted the rate of change in releases (ramp rates) to 2,500 cfs per hour when increasing and to 1,500 cfs per hour when decreasing. While these limitations were imposed, the interim criteria met the minimum annual release of 8.23 million acre-feet in accordance with the 1970 Long-Range Operating Criteria. Although the interim operating criteria could be modified on the basis of new information, they were to remain in effect until the EIS and the Secretary’s Record of Decision for new operating criteria for the dam were completed.

Grand Canyon Protection Act of 1992

Subsequent to Reclamation’s initiation of the EIS process, on October 30, 1992, the Congress enacted the Grand Canyon Protection Act of 1992 (title XVIII of P.L. 102-575). The act addresses the protection of the Grand Canyon National Park, the Glen Canyon National Recreational Area, the interim operating criteria for the dam until the EIS is completed, long-term monitoring and research, and the replacement of lost power from any changes to the dam’s operation. The act requires that the Glen Canyon Dam be operated to protect, mitigate adverse impacts to, and improve the downstream resources of the Grand Canyon National Park and the Glen Canyon National Recreational Area. The act also required the Secretary of the Interior to complete a final environmental impact statement for the Glen Canyon Dam’s operations by October 30, 1994. Furthermore, the act required GAO to audit the costs and benefits of the various operating alternatives identified in the final environmental impact statement. On the basis of the findings, conclusions, and recommendations made in the EIS, other relevant information, and our audit report, the Secretary is to issue a Record of Decision adopting future operating criteria and operating plans for the Glen Canyon Dam.

National Environmental Policy Act

The National Environmental Policy Act of 1969 (NEPA) (42 U.S.C. 4321 et seq.) establishes the national environmental policy and goals for protecting, maintaining, and enhancing the environment, and it provides a process for implementing these goals within federal agencies. The act requires, among other things, that the applicable federal agency prepare a detailed EIS for every major federal action that may significantly affect the quality of the human environment. The EIS is designed to ensure that important environmental impacts will not be overlooked or underestimated before the government commits to a proposed action. The act also established the Council on Environmental Quality, which oversees the NEPA process.

The Council on Environmental Quality’s Regulations for Implementing the Procedural Provisions of the National Environmental Policy Act (40 C.F.R. 1502.4) provide federal agencies with a process for determining whether or not to prepare an EIS. If it is determined that an EIS is necessary, regulations require, among other things, that the EIS must (1) address the purpose of and need for the action, (2) describe the environment that will be affected, (3) identify alternatives to the proposed action, (4) present the environmental impacts of the proposed action (including the direct, indirect, and cumulative impacts), (5) identify any adverse environmental impacts that cannot be avoided should the proposed action be implemented, and (6) identify any irreversible and irretrievable commitment of resources that would occur should the proposed action be implemented. The regulations also require each federal agency to identify the agency’s preferred alternative or alternatives, if one or more exists, in the draft and the final EIS. In addition, before making a decision, the responsible agency must solicit comments from the public and from other government agencies that may have jurisdiction by law or expertise with respect to any environmental impacts.

Under section 309 of the Clean Air Act, the Environmental Protection Agency (EPA) is required to review and publicly comment on the environmental impacts of major federal actions, including actions that are the subject of a draft or final EIS. EPA reviews and comments on both the adequacy of the analyses and the environmental impacts of the proposed action. If the Administrator, EPA, determines that the action is environmentally unsatisfactory from the standpoint of the public’s health or welfare or environmental quality, this determination shall be published and the matter will be referred to the Council on Environmental Quality. If the action involves a federal project located at a specific site, the appropriate EPA regional office has the jurisdiction and delegated responsibility for carrying out the section 309 review and working with the proposing federal agency to resolve any problems. EPA’s Region IX in San Francisco, California, was the region responsible for reviewing the draft and final EIS for the operation of the Glen Canyon Dam.

Reclamation’s Process for Completing the Glen Canyon Dam’s EIS

The preparation of the Operation of Glen Canyon Dam Final Environmental Impact Statement was a cooperative effort involving Reclamation, the cooperating agencies, the participants in the Glen Canyon Environmental Studies program, and the representatives of an interagency EIS team. Although Reclamation was designated to be the lead agency responsible for preparing the EIS, its objective was to obtain substantial input from these organizations during the decision-making process, and its goal was to build a consensus for the ultimate decision of recommending a preferred alternative in the EIS.

The group of cooperating agencies, which prior to the development of the formal EIS included only federal agencies, was established in July 1989. This group ultimately included representatives from Reclamation, the Bureau of Indian Affairs, the Environmental Protection Agency, the National Park Service, the U.S. Fish and Wildlife Service, the Western Area Power Administration, the Arizona Game and Fish Department, the Hopi Tribe, the Hualapai Tribe, the Navajo Nation, the San Juan Southern Paiute Tribe, the Southern Paiute Consortium, and the Pueblo of Zuni. The EIS team was established in mid-1990 and included representatives from Reclamation, the National Park Service, the U.S. Fish and Wildlife Service, the Western Area Power Administration, the U.S. Geological Survey, the Arizona Game and Fish Department, the Hopi and Hualapai Tribes, the Navajo Nation, and a private consulting firm. Reclamation charged the EIS team with formulating alternatives for operating the dam and assessing their impacts on the environment. For resources that were to be studied in detail, subteams were formed to make the impact determinations, document their findings, and draft that particular section of the EIS. For the other resources, individuals with expertise in a particular field were assigned the responsibility for determining the impacts and preparing the documentation. Figure 1.3 shows some of the key dates in the preparation of the Glen Canyon Environmental Studies and the EIS.

Scoping Phase

The initial step in preparing an EIS involves a scoping phase that provides for the early identification and consideration of environmental issues and alternatives. In February 1990, Reclamation published a notice in the Federal Register announcing the opening of the scoping phase of the Glen Canyon Dam’s EIS. This phase included environmental scoping meetings to obtain public comments and determine the appropriate scope of the EIS. The comment period, initially established for March 12 through April 16, 1990, was extended to May 4, 1990, in response to comments by the public. Reclamation provided opportunities for public participation in the scoping phase through news releases, mailings, legal notices, and contacts with media, organizations, and individuals. Throughout the process, the EIS team periodically reported the results of its analyses to the cooperating agencies and the public. The cooperating agencies acted as a steering committee and provided input to Reclamation on both the EIS process and the EIS document after a period of review and discussion.

More than 17,000 comments were received during the scoping period. Numerous comments were received about suggested alternatives and factors to be considered in the development of alternatives. These comments ranged from general suggestions about the management of the dam to specific flow release recommendations. As a result of the analyses and the categorization of the oral and written scoping comments by a Reclamation contractor, the EIS team consolidated and refined the public’s issues of concern. The following resources were identified to be analyzed in detail in the EIS: water, sediment, fish, vegetation, wildlife and their habitat, endangered and other special-status species, cultural resources, air quality, recreation, hydropower, and non-use value.

In July 1990, representatives from the cooperating agencies and various interest groups participated in a “brainstorming” workshop to fully consider all concepts and suggestions in formulating alternatives for the dam’s operations. On the basis of the results of the workshop, scoping comments, and the Glen Canyon Environmental Studies phase I report, the interdisciplinary EIS team formulated 10 preliminary alternative flow scenarios. Some of these alternatives would provide for warmer water release temperatures in the summer, add sediment to the river below the dam, or reregulate releases to provide steady flows downstream. The EIS team presented these alternatives to the cooperating agencies and, following their approval, presented them to the public in March 1991.

The public was asked to comment on the range of preliminary alternatives as part of the EIS scoping process. The predominant public comment was the need to separately consider alternatives that deal with the operations of the dam from those considering changes to the structure of the dam. Using the additional input received from the public, professional judgment, and analysis of interim flows, the EIS team reviewed and revised the preliminary alternatives. Seven alternatives were then identified for detailed analysis. Later, to present a full range of reasonable operations for study in the EIS, two more alternatives were formulated. These included the Maximum Powerplant Capacity alternative, which was developed to allow use of the powerplant’s maximum discharge capacity of 33,200 cfs, and the eventual preferred alternative—the Modified Low Fluctuating Flow alternative. The Modified Low Fluctuating Flow alternative was similar to the Interim Flow but included a habitat maintenance flow. Habitat maintenance flows are high, steady releases of water within the powerplant’s capacity for 1 or 2 weeks in the spring. The purpose of these flows is to reform and rejuvenate backwaters and maintain sandbars, which are important for native fish habitat. Table 1.1 presents the nine alternative flows studied in detail in the Glen Canyon Dam’s environmental impact statement. These alternatives can be categorized as follows: unrestricted fluctuating flows, restricted fluctuating flows, and steady flows.

Resource Protection Measures (Common Elements)

All of the restricted fluctuating flow and steady flow alternatives include elements designed to provide additional resource protection or enhancement. Since these elements were common to all such alternatives, they became known as the “common elements.” Each impact analysis includes these common elements. The common elements include adaptive management, monitoring and protecting cultural resources, flood frequency reduction measures, beach/habitat-building flows, further study of selective withdrawal structures, measures to increase populations of an endangered fish—the humpback chub, and emergency operating exception criteria.

Adaptive Management

The concept of adaptive management is based on the recognized need for operational flexibility to respond to future monitoring and research findings and varying resource conditions. The purpose of the Adaptive Management Program would be to develop future modifications to the dam’s operating criteria if monitoring and/or research results indicate a need for change. Long-term monitoring and research would measure how well the selected alternative meets the resource management objectives. The basis for any decision would be linked to the response of the resources to the operations of the dam. (Further details on the Adaptive Management Program are provided in ch. 2.)

Monitoring and Protecting Cultural Resources

The existence and operation of Glen Canyon Dam has had an effect on the historic properties within the Colorado River corridor of the Glen and Grand canyons. These properties include prehistoric and historic archeological sites and Native American traditional cultural properties and resources. Impacts are likely to occur to some of these historic properties regardless of the EIS alternative chosen for implementation. The National Historic Preservation Act, as amended in 1992, instructs federal agencies to develop measures to avoid or minimize the loss of historic properties resulting from their actions.

Flood Frequency Reduction Measures

Under this common element, the frequency of unscheduled flood flows greater than 45,000 cfs would be reduced to no more than once in 100 years as a long-term average. This would allow management of certain other common elements—habitat maintenance flows and beach/habitat-building flows.

The two separate methods of reducing flood frequency that were identified include (1) increasing the capacity of Lake Powell by raising the height of the spillway gates by 4.5 feet and (2) reducing the volume of the lake by 1 million acre-feet from its current capacity in the spring until the runoff peak has clearly passed.

Beach/Habitat-Building Flows

Sandbars above the river’s normal peak stage will continue to erode, and backwater habitat within the river’s flow will tend to fill with sediment under any EIS alternative. Beach/habitat-building flows involve controlled high releases of water greater than the powerplant’s capacity for a short duration; they are designed to rebuild high-elevation sandbars, recycle nutrients, restore backwater channels, and provide some of the dynamics of a natural system.

Further Study of Selective Withdrawal Structures

Reclamation would perform a study to determine if structures that would allow the withdrawal of water from various depths of the reservoir should be installed at the Glen Canyon Dam. Currently, water released from the dam to produce hydropower is withdrawn from the cold depths of Lake Powell, averaging 230 feet below the water’s surface when the reservoir is full. This withdrawal process is accomplished by a series of eight 15-foot-diameter intake pipes that provide the water directly to the dam’s eight turbines. This water withdrawal process results in the river water temperature downstream of the dam being a nearly constant year-round average of about 46 degrees Fahrenheit. Many native fish species cannot reproduce and survive in these constant cold temperature conditions. Increasing mainstream water temperatures by means of selective withdrawal structures offers the greatest potential for creating new spawning populations of humpback chub and other native fish in the Grand Canyon. Multilevel intake structures (a means of selective withdrawal) could be built at Glen Canyon Dam to provide seasonal variation in the water temperature. A structure would be attached to each of the eight existing intake pipes to withdraw warmer water from the upper levels of the reservoir. However, the cost of installing multilevel intake structures at the Glen Canyon Dam has been estimated at $60 million.

New Population of Humpback Chub

With the assistance of the U.S. Fish and Wildlife Service, the National Park Service, the Arizona Game and Fish Department, and other land management entities, such as the Havasupai Tribe, Reclamation would make every effort—through funding, facilitating, and technical support—to establish a new population of humpback chub within the Grand Canyon. The humpback chub is currently a listed species under the federal Endangered Species Act of 1973 (16 U.S.C. 1532 et seq.) and is one of the native fish species that faces continued ecological health problems due to the cold water temperatures of the Colorado River. Such cold temperatures are not conducive to the humpback chubs’ spawning or the survival of eggs and young.

Emergency Exception Criteria

Normal operations described under any alternative could be altered temporarily to respond to power and water emergencies, such as insufficient generating capacity, the restoration of the electrical system, or search and rescue operations. These changes in operations would be of short duration (usually less than 4 hours) and would be the result of emergencies at the dam, downstream, or within the interconnected electrical system.

Draft EIS and Public Comments

On January 4, 1994, Reclamation filed a draft EIS with EPA. The Draft EIS presented the impacts of the nine flow alternatives, including the No-Action alternative (historic operations) that provided a baseline for comparison, on the 11 resources that could be affected by the various dam-operating regimes. Over 33,000 written comments were received on the draft EIS. More than 2,300 separate issues and concerns were extracted from an analysis of the comments.

EPA’s Region IX supported the preferred alternative (Modified Low Fluctuating Flow) selected by Reclamation in the draft EIS. However, EPA gave the draft EIS a qualified rating based on insufficient information on two issues. First, EPA expressed concern about the lack of information on the impacts of raising the dam’s spillway gates as a flood frequency reduction measure and recommended that the final EIS include a more thorough evaluation of the flood frequency reduction options. Second, EPA recommended that the final EIS contain further discussion of Reclamation’s Adaptive Management Program and how it plans to implement beach/habitat-building flows.

Preliminary Final EIS

Reclamation issued a preliminary final EIS for the operations of the Glen Canyon Dam in December 1994. The preliminary final EIS also took into consideration the discussions with the U.S. Fish and Wildlife Service (FWS) in connection with the consultation requirements of the Endangered Species Act and with the provisions of the Fish and Wildlife Coordination Act. Section 7 of the Endangered Species Act, as amended (16 U.S.C. 1536), requires federal agencies to consult with FWS to ensure that the actions they authorize, fund, or carry out are not likely to jeopardize the continued existence of a species listed under the act as endangered or threatened. If the action would jeopardize a listed species, FWS suggests a reasonable and prudent alternative that the federal agency can implement to minimize and/or mitigate the activity’s impact on the species or their critical habitat. The Fish and Wildlife Coordination Act of 1958 (16 U.S.C. 661 et seq.) was enacted to ensure that fish and wildlife receive equal consideration during the planning and construction of federal water projects. FWS prepares a Fish and Wildlife Coordination Act report that contains nonbinding recommendations for actions that would be beneficial to fish and wildlife. The cooperating agencies and the EIS team reviewed the preliminary final EIS, and additional changes were made to the EIS on the basis of that review.

Final EIS

On March 21, 1995, Reclamation filed the final EIS with EPA. In June 1995, EPA informed Reclamation that it continues to support the preferred alternative and was pleased that Reclamation had addressed EPA’s concerns about the draft EIS. Specifically, the final EIS states that Reclamation will conduct a detailed evaluation of the flood frequency reduction measures before a decision is made and provides more information on the approach that Reclamation will use to implement an Adaptive Management Program and conduct beach/habitat-building flows. EPA applauded the efforts made by all of the agencies, tribes, organizations, and individuals involved in the research, scoping, and preparation of the EIS. EPA summarized that the dedication to sound science and cooperative relations was critical to developing a preferred alternative (including adaptive management), which it believes will protect and enhance the environmental and cultural resources downstream from the Glen Canyon Dam.

Reclamation’s Preferred Alternative for Future Operations of the Glen Canyon Dam

In the Glen Canyon Dam’s final environmental impact statement, Reclamation recommends the Modified Low Fluctuating Flow as the preferred method for the future operations of the Glen Canyon Dam. According to the final EIS, the Modified Low Fluctuating Flow alternative was developed to reduce daily flow fluctuations well below no-action levels and to provide periodic high, steady releases of short duration, with the goal of protecting or enhancing downstream resources while allowing limited flexibility for power operations. This alternative would have the same annual and essentially the same monthly operating plan as under the No-Action alternative but would restrict daily and hourly water releases. Specifically, minimum flows would be no less than 8,000 cfs between 7 a.m. and 7 p.m. and 5,000 cfs at night. The maximum rate of release would be limited to 25,000 cfs during fluctuating hourly releases. Ramp rates would be limited to 4,000 cfs per hour for increasing flows and 1,500 cfs per hour for decreasing flows. Daily fluctuations would be limited to 5,000, 6,000, or 8,000 cfs depending on the monthly release volume.

The preferred alternative also included periodic habitat maintenance flows, which are steady high releases within the powerplant’s capacity for 1 to 2 weeks in the spring. The purpose of these flows is to rejuvenate backwater channels that are important to fish habitat and maintain sandbars that are important for camping. Habitat maintenance flows differ from beach/habitat-building flows in that they would be within the powerplant’s capacity and would occur nearly every year when the reservoir’s volume is low. According to Reclamation, when the reservoir is low, water flows normally would not exceed about 22,000 cfs, and the probability of an unscheduled spill is small. Therefore, the habitat maintenance flows would be scheduled in those years. Habitat maintenance flows would not occur in years when a beach/habitat-building flow is scheduled. Beach/habitat-building flows are controlled floods with scheduled high releases of water greater than the powerplant’s capacity for a short duration, designed to rebuild high elevation sandbars, deposit nutrients, restore backwater channels, and provide some of the dynamics of a natural river system.

According to Reclamation, instead of conducting the beach/habitat building flows in years in which Lake Powell storage is low on January 1, it has been agreed to modify the preferred alternative in the Record of Decision to accomplish the flows in high reservoir years when bypassing the powerplant would be necessary for safety purposes at the dam. In the spring of 1996, Reclamation conducted its first experiment of the controlled flood concept. The controlled experiment commenced with 4 days of constant flows at 8,000 cfs. Flows began to increase incrementally on March 26, 1996, until they reached a maximum of 45,000 cfs, where they remained for 7 days. After 7 days of high flows, the releases were reduced, gradually, to a constant flow of 8,000 cfs for 4 days of evaluation. According to Reclamation, the preliminary results indicate that the release increased sandbars in the Glen and the Grand canyons by as much as 30 percent and also created numerous backwaters for fish.

Objectives, Scope, and Methodology

Subsection 1804(b) of the Grand Canyon Protection Act states that the Comptroller General shall (1) audit the costs and benefits to water and power users and to natural, recreational, and cultural resources resulting from the management policies and dam operations identified pursuant to the environmental impact statement and (2) report the results of the audit to the Secretary of the Interior and the Congress.

While the act states that GAO should audit the “costs and benefits” of various alternative dam operations identified in the EIS, the National Environmental Policy Act does not require, and Reclamation did not perform, a cost and benefit analysis. In preparing the impact statement, Reclamation studied the impact of nine dam-operating alternatives on 11 resources. In the absence of a cost and benefit analysis, we determined that the statute does not require us to conduct our own cost and benefit analysis. As discussed with the staff of the Majority and Ranking Minority members of the Senate and House committees having jurisdiction over these matters, to fulfill the requirements of the act, we examined • whether Reclamation’s determination of the impact of various flow alternatives on selected resources was reasonable and • what, if any, concerns still exist on the part of key interested parties about the final EIS.

To assess whether Reclamation’s impact determinations were reasonable, we assessed for each resource, the methodologies and data used to make the impact determinations, how the methodologies were implemented, and the results achieved. The details of our analysis, and a comprehensive list of individuals contacted and key studies identified, are contained in appendixes I through X of this report. The title of each appendix is the designation (name) of the resource, and they are numbered in alphabetical order. We combined our analysis of the vegetation and wildlife/habitat impact determinations into one appendix—appendix IX. We made this choice because (1) similar indicators were studied in making the impact determinations for these resources, (2) the riparian vegetation that developed along the Colorado River corridor plays an important role as habitat to support the diversity of wildlife within the Glen and the Grand canyons, and (3) the same EIS team member was responsible for the impact determinations of both resources.

For three resources—hydropower, recreation, and non-use values—Reclamation quantified the economic impact of the cost or benefit that the various flow alternatives would have on the resource. For these resources, we also reviewed the documentation on the modeling techniques and economic assumptions used to make the impact determinations. For example, for Reclamation’s power methodology, we reviewed key economic assumptions, results, and documentation, including reports entitled Power System Impacts of Potential Changes in Glen Canyon Power Plant Operations, Final Report, October 1993, and Power System Impacts of Potential Changes in Glen Canyon Power Plant Operations, Phase III Final Report, July 1995. These reports were prepared by the Power Resources Committee, a subgroup of the EIS team which included experts from the federal government, the utility industry, and the environmental community. This committee was charged with determining the impact of the nine flow alternatives on hydropower.

We interviewed members of the Power Resources Committee, including the Reclamation officials who served as Chairman and economist, and representatives from the Western Area Power Administration, the Colorado River Energy Distributors Association, the Environmental Defense Fund, and the Reclamation contractor that conducted the studies.

In addition, to assess the methodology used, economic assumptions, and results, we reviewed federal guidance on water resource projects entitled Economic and Environmental Principles and Guidelines for Water and Related Land Resources Implementation Studies, U.S. Water Resources Council, March 10, 1983; public comments on the draft and final EIS, and comments provided by three energy consultants retained by HBRS, Inc. to review the power analysis. HBRS, Inc. (now called Hagler Bailly Consulting), was Reclamation’s primary contractor for conducting the power analysis. Also, we reviewed the comments provided by the National Research Council on the power analyses in the draft and final EIS. We used standard microeconomic principles to assess the reasonableness of key economic assumptions. Our assessment of the reasonableness of Reclamation’s methodology was limited to a review of the general analytical framework and an assessment of the reasonableness of the key assumptions and data. We did not evaluate the Power Resources Committee’s calibration of the power simulation models used or the spreadsheet models used, nor did we verify the accuracy of all data inputs.

For both the recreation and non-use methodologies, we reviewed the literature and research principles on the contingent valuation method to assess the reasonableness of the methodology, assumptions used, and results in conjunction with standard economic principles. Economists and survey researchers working in the natural resource and environmental areas have developed the theory and practice of contingent valuation to estimate non-use values.

To gain an understanding of Reclamation’s recreational methodology, key assumptions, and results, we reviewed documentation that describes these in detail, including the EIS. We also interviewed members of the Recreation subgroup, including Reclamation officials and their contractors, as well as representatives from the National Park Service and the Arizona Game and Fish Department. In addition, we interviewed academic experts in the field and a member of the National Academy of Sciences’ team that reviewed the EIS.

To gain an understanding of Reclamation’s non-use value study methodology and results, we reviewed the final report entitled GCES Non-Use Value Study, dated September 8, 1995. We interviewed Reclamation officials responsible for the preparation of the report, and a Senior Associate at Hagler Bailly Consulting, who was a primary contributor to the development of the report. To evaluate Reclamation’s non-use study, we made use of some general guidelines that focus on the quality of a contingent valuation study and on the underlying survey research. Specifically, to assess the contingent valuation study, we relied on general guidelines developed by a panel of prominent researchers convened by the National Oceanic and Atmospheric Administration. The panel’s report was published in the Federal Register on January 15, 1993. To assess the total design method for conducting mail surveys used by Reclamation in the non-use study we used the most widely accepted written standards for mail questionnaires published by Don A. Dillman in 1978. We also interviewed a number of the Non-Use Value Committee members to obtain their opinion of the methodologies and data used and the results achieved. The Committee included members from the power industry, environmental groups, Native American tribes, and federal agencies. The Committee was tasked to consider interim study results and provide input to the study process.

For the eight resources whose impact determinations were not economically quantified, to determine the methodology and data used to make an impact determination, we obtained and reviewed the following documents: the draft EIS and associated appendixes, the preliminary final EIS, the final EIS, public comments on the draft EIS, Reclamation’s analysis of and responses to these comments, copies of the minutes of EIS team meetings, summaries of the cooperating agency meetings, and Reclamation’s newsletters on the EIS process. We also obtained and reviewed the U.S. Fish and Wildlife Service’s draft biological opinion and final biological opinion on the Glen Canyon Dam’s EIS, Reclamation’s comments and responses to the biological opinions, and the U.S. Fish and Wildlife Service’s report required by the Fish and Wildlife Coordination Act. Also, we reviewed numerous scientific studies related to each of the resources that were identified by EIS team members as the most useful in developing the impact determinations for the respective resources.

To obtain a better understanding of other issues related to the EIS process, we also reviewed the Colorado River Simulation System Overview, the Final Analysis Report on Scoping Comments, and the Glen Canyon Dam EIS Preliminary Alternatives Report. Other documents reviewed included the draft and final environmental assessment of the spring 1996 beach/habitat-building test flow and papers presented at a 1991 National Research Council Symposium on the Glen Canyon Environmental Studies.

Because certain parameters included in the preferred alternative were changed, we reviewed a document entitled “Assessment of Changes to the Glen Canyon Dam Environmental Impact Statement Preferred Alternative from Draft to Final EIS,” issued by Reclamation in October 1995. This paper explained the background and scientific basis of the changes to the preferred alternative between the draft and final EIS. A comprehensive list of the documents we reviewed is contained in the discussion of each of the 11 resources in appendixes I through X (vegetation and wildlife/habitat are both discussed in appendix IX).

To assess the reasonableness of the impact determinations for the eight resources that were not economically quantified, we interviewed the EIS team members and/or subgroup members who had the primary responsibility for making the impact determinations, writing sections of the draft EIS, and revising the EIS following the receipt of public comments. We also spoke with scientists identified by EIS team members and members of EIS subgroups who commented on issues in their area of expertise. Finally, we interviewed other agency officials with information on the EIS and Glen Canyon Environmental Studies processes. For each of these resources, we obtained his or her views on the reasonableness of the methodology and data used in making the impact determinations, how well the methodologies were implemented, and the reasonableness of the results achieved.

To obtain information on what, if any, concerns still exist on the part of key interested parties about the final impact statement, including how many supported the preferred alternative, we surveyed 37 key organizations and individuals knowledgeable about the EIS and its development. Our judgmental sample included officials of federal agencies, state agencies, Indian tribes, environmental organizations, water and power suppliers and users, and individuals involved in the development of the EIS. Specifically, among the 37 organizations and individuals we asked to respond to our survey, 23 were organizations and individuals that provided what Reclamation considered to be the most substantive comments on the draft EIS. These agencies and individuals include the Navajo Nation, Hualapai Tribe, Hopi Tribe, Bureau of Indian Affairs, National Park Service, Arizona Game and Fish Department, U.S. Fish and Wildlife Service, Western Area Power Administration, Plains Electric Generation and Transmission Coop, Inc., Environmental Protection Agency, Environmental Defense Fund, National Research Council, Upper Colorado River Commission, Department of the Interior’s Office of Environmental Policy and Compliance, Salt River Project, Colorado River Energy Distributors Association, Grand Canyon Trust, American Rivers, Sierra Club Legal Defense Fund, American Fisheries Society, Grand Canyon River Guides, and Dr. Larry Stevens. Dr. Stevens is considered by many to be the leading authority on vegetation in the Grand Canyon region. He was a major contributor of research on both the vegetation and wildlife/habitat resources for the EIS. We also contacted Mr. David Marcus, whom Reclamation stated also provided substantive comments on the draft EIS. However, Mr. Marcus stated that he worked as a consultant for American Rivers and that he preferred to provide us with his comments through that organization, not as an individual. As such, we did not include Mr. Marcus as part of our survey universe.

We also contacted the three cooperating agencies (Pueblo of Zuni, Southern Paiute Tribe, and Southern Paiute Consortium) that were not among the 22 above. Furthermore, the seven Colorado River Basin states (Arizona, California, Colorado, Nevada, New Mexico, Utah, and Wyoming) were asked to respond to our survey. In addition, another five environmental groups with interests in the Glen Canyon Dam area (Sierra Club, Arizona Flycasters, Friends of the River, America Outdoors, and Trout Unlimited) were also contacted. We received responses from 30 of the 37 (81 percent) organizations and individuals we contacted. The seven nonrespondents did not represent any particular interest group. Specifics on how the 37 organizations and individuals responded to our survey are provided in chapter 3 of this report.

We conducted our work from January 1995 through September 1996 in accordance with generally accepted government auditing standards.

We provided copies of a draft of this report to the Department of the Interior for its review and comment. Interior generally agreed with the information presented in the report and stated that they were impressed with the quality of the product developed by the audit team. Interior also provided several technical clarifications to the draft, which have been incorporated into the report as appropriate. Interior’s comments and our responses are included in appendix XII.

Reclamation’s Impact Determinations Are Usable for Decision-Making

In preparing the Glen Canyon Dam’s environmental impact statement, Reclamation studied the impact of the dam’s various flow alternatives on hydropower, non-use values, and other selected resources located below the dam. To make these impact determinations, Reclamation used a variety of methodologies and data sources. Generally, we believe the methodologies used to be reasonable and appropriate and the data used to be the best available at the time. Some prominent economists, however, question the credibility of results obtained from the methodology Reclamation used to derive non-use values. We also noted some shortcomings in some of Reclamation’s economic assumptions and its application of certain methodologies. In addition, we found that some of the data used in the resource analyses were dated, preliminary, or incomplete. Overall, these limitations reduce the precision of the estimated impacts contained in the EIS. In addition, there is general agreement that as a result of incomplete information, the impact of steady flow alternatives on fish resources remains uncertain. Nonetheless, our work disclosed no evidence that these limitations would alter the relative ranking of the fluctuating and steady flow alternatives. Therefore, we believe that these limitations are not significant enough to render the final impact statement unusable to the Secretary of the Interior as a decision-making document.

Generally, Reclamation and other experts associated with the development of the Glen Canyon Dam’s environmental impact statement believe that the impact determinations are reasonable. At the same time, they recognize that there are limitations to the EIS. However, they believe that these limitations are not significant enough to make the results unusable. Furthermore, Reclamation recognizes that many uncertainties still exist. To address these uncertainties, Reclamation intends to initiate a process of “adaptive management” that would provide for long-term monitoring and research to measure the actual effects of the selected alternative. The results of this effort would form the basis for possible future modifications of the dam’s operations.

Methodologies Used to Make Impact Determinations Were Generally Reasonable

We found that, in general, the variety of methodologies and research techniques used by Reclamation to make impact determinations were reasonable and appropriate. For most resource assessments, Reclamation relied on multidisciplinary subteams consisting of experts representing federal and state governments, tribal interests, academic and scientific communities, the electric utility industry, environmental organizations, and the recreation industry. The exact makeup of each team depended on the resource and the area of concern. In addition, for each resource, the subteam assessed, either quantitatively, qualitatively or both, how alternative flows would affect the resource relative to a No-Action (base case) flow. The EIS teams generally used state-of-the-art modeling techniques and/or the latest scientific research to make the impact determinations. Furthermore, the methods used and results achieved were reviewed by peers and outside experts, including the Glen Canyon Environmental Studies Review Team and the National Academy of Sciences.

To conduct the impact analyses of various flows on hydropower, Reclamation established the Power Resources Committee—a group of electricity and modeling experts from Reclamation, the Western Area Power Administration, the electric utility industry, private contractors, and the environmental community. Using a 50-year analysis period (1991-2040) and the No-Action Flow alternative (historic operations) as the base case, the Committee assessed how various flow alternatives would affect hydropower production and then projected the subsequent economic costs that would be incurred by regional utilities and end-users to replace the dam’s forgone power production. The Committee considered the fixed costs associated with the existing generating capacity in the region to be “sunk” costs and, hence, excluded them from the economic cost calculations. The Committee also used two state-of-the-art modeling techniques and detailed utility-specific data to quantify the economic impacts. In addition, the Committee used sensitivity analysis to test the impact of changes in key economic assumptions. The results of the power study were then incorporated into the draft EIS for public comment. The Committee solicited and received an independent review of the power study from three energy experts. On the basis of the comments received from the public and outside experts, the Committee partially revised its initial power study. For example, the Committee updated the projected costs of building gas-combustion powerplants, revised its retail rate analysis, and conducted additional sensitivity analyses. The results of both power studies were incorporated into the final EIS. (See app. V for details on the results of the power study.)

For fish resources, numerous public comments were received by Reclamation expressing concern about the impact determinations presented in the draft EIS. To respond to these concerns, Reclamation formed an Aquatic Biology Team workgroup. This work group consisted of EIS team members representing Reclamation, the U.S. Fish and Wildlife Service, the Arizona Game and Fish Department, and two Indian tribes.

The workgroup was tasked to respond to comments and to reorganize and rewrite the fish section of the final EIS. Individual workgroup members were given specific assignments, interactive discussions were held, and decisions were made through consensus. As a result of this effort, several major changes were made to the final EIS, including more explicit recognition of the uncertainty and disagreement that exist among scientists about the response of fish to the steady flow alternatives. (See app. IV for details on the results of the fish impact determinations.)

To assess the impact of various flow alternatives on water and sediment, Reclamation’s EIS team used the Colorado River Simulation System (CRSS) to project the long-term (50 years) and short-term (20 years) impacts on annual and monthly streamflows, floodflows and other water spills, water storage, water allocation deliveries, and Upper Colorado River Basin yields. CRSS is a package of computer programs and databases designed to assist water resource managers in performing comprehensive long-range planning and operations studies that arise from proposed changes in the Colorado River’s operations, proposed development of the Colorado River Basin, or changes in present water use throughout the basin. The development of CRSS took place over a 10-year period and stemmed from the need for a comprehensive model of the Colorado River Basin that would incorporate all areas of interest, including legislative requirements. According to Reclamation and other experts, CRSS is the most comprehensive and detailed simulation of the Colorado River system that exists. (See app. VIII and app. X for details on the results of the sediment and water analyses, respectively.)

To quantify the economic impact of the dam’s various flow alternatives on non-use values and recreation, Reclamation primarily relied on a methodology called contingent valuation. Social scientists and economists have long acknowledged the existence of non-use values—the monetary value placed on the status of the environment by people who never visit or otherwise use these features. Contingent valuation relies on public surveys to elicit information from consumers and estimate how much they would be willing to pay for a non-use good. For valuing most goods and services, economists are able to rely on people’s actual purchases of goods in markets. However, by definition people do not purchase non-use goods, and some prominent economists question whether the contingent valuation method can accurately elicit the values consumers place on non-use goods. For example, Peter A. Diamond and Jerry A. Hausman state, “We believe that contingent valuation is a deeply flawed methodology for measuring non-use values, one that does not estimate what its proponents claim to be estimating.” Still many economists and survey researchers working in the natural resource and environmental areas have developed and used this methodology, and it is currently the only known approach for estimating non-use values. (See app. VI for details on the results of the non-use value study.) Economists generally have fewer questions about the application of the contingent valuation methodology in measuring the value of goods and services that consumers actually purchase. Therefore, there are fewer questions about the usefulness of this approach for measuring the values associated with recreational activities. (See app. VII for details on the results of the recreation studies.)

Shortcomings Noted in Reclamation’s Economic Assumptions and Implementation of Certain Methodologies

In light of the results of our work and the opinions of the experts we contacted, we believe the methodologies used by Reclamation and its EIS teams to make impact determinations were generally reasonable. We did note, however, some shortcomings in the economic assumptions used in the hydropower analysis and in Reclamation’s implementation of certain methodologies. Specifically, in the hydropower analysis, the assumptions used do not explicitly include the mitigating effect that higher electricity prices would have in reducing the demand for electricity (that is, price elasticity). For example, the Power Resources Committee assumed that both the demand for and price of electricity would continue to rise over the planning period. However, we believe the rise in the price of electricity would likely induce some electricity consumers (both wholesalers and end-users) to consume less electricity or switch to cheaper alternative suppliers, which is not taken into account in the analysis. Consequently, fewer resources would be needed to replace forgone power at the Glen Canyon Dam, and the subsequent economic impacts would be lower than estimated (all else being the same).

In addition, the Committee’s assumptions about future natural gas prices are relatively high. The Committee assumed that the average gas price would increase annually by 8 percent from 1991 through 2010. In 1994, industry forecasters projected that the price of natural gas would increase by about 6 percent for the same time period, and in 1995, forecasts assumed that prices will rise by only 5 percent. The higher escalation rates could affect the power analysis by overstating the economic cost of replacing the Glen Canyon Dam’s power.

We also found that Reclamation’s staff made two computational errors during the revision of the initial power analysis. The Power Resources Committee acknowledged these errors in its final report and stated that the errors affected the results in opposite directions, that is, one error may have overstated costs while the other error may have understated costs. The Committee was unable to correct the errors in the report because of time and funding constraints.

These shortcomings, combined with the inherent uncertainty in making economic forecasts, reduce the precision of the estimated economic impacts. However, an association that represents the affected power utilities, while maintaining that the costs to the power system are understated, does not believe that Reclamation’s analysis is inaccurate by a large magnitude. Furthermore, because these shortcomings affect the estimated economic impact of all alternatives equally, we believe that addressing these shortcomings would not alter the relative ranking of the fluctuating and steady flow alternatives.

Although we believe the recreation impacts methodology is generally reasonable, we noted several limitations. For example, the survey data used as the basis of the analysis were gathered during an unusually high-water year; therefore, some respondents may not have actually experienced how various alternative flows would have affected their recreational experience, which is what they were being asked to value. In addition, the survey was designed well before the flow alternatives to be studied in the Glen Canyon Dam’s EIS were finalized. As a result, the survey scenarios do not systematically correspond to the flow alternatives presented in the EIS. Finally, although researchers tested proposed questions to determine which ones offered the highest response rate, they did not adequately pretest some survey instruments to detect wording, construction, and presentation defects or other inadequacies. Because the recreation economic model used the results of these survey instruments as a basis for the analysis, the estimated dollar value of the benefits may not be very precise. Reclamation and National Park Service officials involved in the process acknowledged that the recreation analysis has limitations but stated that these limitations would not affect the ranking of the alternatives. They also noted that the estimated recreation benefits identified by this research were not a key element in the selection of the preferred alternative.

In addition to the shortcomings in the hydropower and recreation analyses, we also noted that there was no formal opportunity for affected parties as well as the general public to offer comments on the Glen Canyon non-use value study. Although the final EIS notes that the non-use value is positive and significant, the actual quantified results are not included in the final EIS. Reclamation did not include the non-use value study results because they were not available when the final EIS was published. The non-use study was completed as a separate Glen Canyon Environmental Studies report and, according to Reclamation, will be attached to the Record of Decision package sent to the Secretary of the Interior. In that way, it will become part of the final decision-making process. Reclamation noted that although the non-use study did not go through the public comment process, the study team solicited and received peer review at various key decision points and that the final results of the non-use value study received a positive review by the National Academy of Sciences and the Office of Management and Budget. Reclamation also noted that interests likely to be affected by any changes in the operations of the Glen Canyon Dam, such as power groups and environmental groups, were involved in the non-use value study process. In addition, there were scoping sessions and focus groups that were derived from members of the general public. The results of these sessions were used to assist in the development of the content of the survey and the relevant issues to be addressed.

Data Used in Impact Determinations Were the Best Available

Reclamation’s National Environmental Policy Act Handbook requires that all EIS analyses be based on the best reasonably obtainable scientific information. According to Reclamation and other experts who developed the Glen Canyon Dam’s environmental impact statement, the data used to make the impact determinations were the best available at the time. For example, for the impact of various flow alternatives on nonfish endangered species, one researcher said the terrestrial and bird-related research used as a basis for making impact determinations was “top notch.” Another researcher who worked on endangered species stated that when they were clarifying information or needed data to fill gaps, the EIS team contacted researchers directly to get the latest available data. For information on cultural resources and properties, members of that resource team believe that Reclamation went beyond federal requirements for the development of an impact statement by performing assessments of all previously identified archeological sites within the Colorado River corridor in the Glen and Grand canyons. According to many experts, when completed, this effort generated the best and most current scientific information available.

For some resources, we found that although the data were the best available, they had limitations. Some of the data used in making the impact determinations were dated, preliminary, or incomplete. For example, Reclamation used survey data collected in 1985 to assess the economic impact of alternative dam flows on recreational activities. Reclamation’s contractor surveyed a sample of anglers, day-rafters, and white-water boaters about their recreational experiences on the Colorado River and what effect, if any, different streamflows would have on their recreational experiences. However, because the survey was undertaken in 1985, it may not represent more recent trends in recreational experiences. For example, the number of angling trips on the Colorado River more than doubled between 1985 and 1991 (the base year used by Reclamation in preparing the draft EIS), which may influence the value of each trip. Reclamation updated some of the data to 1991 but acknowledges that the survey data were generally dated. Reclamation stated, however, that the recreation analysis was adequate to present a good picture of the potential impact of alternative flows on various recreational experiences and that because of the limited impact of alternative flows on recreation, limited research funds could be better used to improve other analyses. The National Research Council generally found the recreation analysis to be adequate.

In addition, the estimated non-use values for the steady flow alternatives could be overstated because of new information that was not available at the time the survey instruments were developed. The non-use value surveys described the environmental impacts based on information that was the best available at the time. This information indicated that improvements would be obtained for fish resources under fluctuating and steady flow alternatives. However, after the development of the survey instruments, the fish section of the EIS was revised to recognize the uncertainty that exists about the impact of steady flow alternatives. To the extent that the non-use value surveys did not capture this degree of uncertainty, the precision of the non-use value estimates could be reduced.

Many of the results of the Glen Canyon sediment studies were preliminary, in draft form, and had not been published at the time that the draft impact statement or the final impact statement was written. In addition, in some cases definitive information on the impact of a specific flow alternative was not available. Therefore, the EIS team had to extrapolate from the existing data using their professional judgment to estimate the potential impact of a specific alternative. The EIS team told us that they always verified the reasonableness of their conclusions and extrapolations with the researchers. However, they believed that if finalized data had been available, the reasons for the selection of the preferred alternative would have been more clearly supported. These researchers added that no new or additional information on sediment impacts has been obtained that would alter the information or conclusions presented in the final impact statement.

Finally, information on some resources is incomplete, as is the knowledge of how changes in the Glen Canyon Dam’s operations will affect those resources. For example, the experts’ opinions vary, in part because of incomplete data, on how native and nonnative fish interact and how changes to the dam’s operations would affect these interactions. Many researchers and EIS team members we interviewed expressed regret about the lack of coordinated time frames between the completion of the Glen Canyon Environmental Studies and the development of the Glen Canyon Dam EIS. The leader of the workgroup responsible for developing the EIS impact determinations for fish stated that this difference in time frames was especially problematic when the preferred alternative was selected. At that point, decisions had to be made, but data and analyses were not complete.

Reclamation explicitly acknowledges the uncertainty that exists about the impact of the steady flow alternatives on fish resources in the final EIS. In its final biological opinion, the U.S. Fish and Wildlife Service stated that Reclamation’s preferred alternative is likely to jeopardize the existence of two native endangered fish species (the humpback chub and the razorback sucker). In general, the biological opinion’s “reasonable and prudent alternative” would modify the preferred alternative by including seasonally adjusted steady flows. The U.S. Fish and Wildlife Service and Reclamation have agreed to categorize these flows as experimental and include them as part of the Adaptive Management Program.

The Results of the Glen Canyon Dam’s EIS Are Generally Reasonable, but Future Studies Will Be Needed

Reclamation and other experts associated with the development of the Glen Canyon Dam’s EIS generally believe that the impact determinations presented in the final EIS are reasonable. (A summary of Reclamation’s comparison of alternatives and impacts is presented in app. XI of this report.) They recognize that there are limitations to the results, but they believe that these limitations are not significant enough to make the impact determinations unusable for the Secretary’s decision-making. For example, one EIS team member stressed that in the process of scientific decision-making and economic forecasting, complete and certain information is never available. Furthermore, Reclamation noted that the Congress had mandated that the final EIS be issued within a certain time frame; therefore, decisions had to be made on the basis of the best information available at the time.

Reclamation recognizes that uncertainties still exist about the impact of the various flow alternatives on resources. To address these uncertainties, Reclamation intends to initiate a process of “adaptive management.”

Impact Determinations in the Glen Canyon Dam’s EIS Are Generally Reasonable

We discussed the results of the impact determinations for each resource with Reclamation and other experts involved in the development of the Glen Canyon Dam’s EIS. Although these individuals recognized that there were some shortcomings in the analyses, they generally agreed that the results of the impact determinations as presented in the Glen Canyon Dam’s final EIS were reasonable. For example, although some researchers described the model used (the sand-mass balance model) to determine the impact of various flows on sediment as “simplistic” compared with models that are currently being developed by U.S. Geological Survey researchers, none of the preliminary results from the new models contradict the conclusions reached by the sand-mass balance model. Another researcher who worked on the vegetation and wildlife resources told us that although the EIS may have been based on incomplete information, subsequent science supports it. The researcher further added that the results of the EIS were right on track with the best scientific evidence available at the time.

The results of some impacts, however, such as how steady flows will affect fish, are still uncertain. The individual responsible for leading the fish impact determinations process stated that the lack of final results from the fish research studies was frustrating and that the limited data allowed differences of opinion and scientific interpretation to arise about the impacts on fish resources. However, he added that he believed that if final data had been available, they would have refined the EIS team’s conclusions but would not have changed the impact determinations or the preferred alternative.

Although there is general agreement that the results of the Glen Canyon Dam’s EIS are reasonable, there is also general agreement that additional research is needed to further refine or, in the case of fish resources, define the impact on resources of changes to the dam’s operations. For example, impacts to some archeological and cultural properties are bound to occur regardless of the flow alternative chosen. To avoid or minimize the loss of historic properties and comply with the requirements of the National Historic Preservation Act, Reclamation developed a programmatic agreement between federal and state agencies as well as affected Native American tribes. Implemented in 1994, the agreement led to numerous monitoring trips and site-stabilization efforts, but all parties involved believe that more research is needed to understand how water flow affects cultural resources. Furthermore, several sediment researchers we interviewed stated that they supported the impact determinations and the preferred alternative. However, one stated that as more information is obtained about the various systems in the canyon, the preferred alternative may become less restrictive in terms of the allowed water releases for hydropower use.

Reclamation’s Proposed Adaptive Management Program

Reclamation recognizes that uncertainties exist about the downstream impacts of water releases from the Glen Canyon Dam. To address these uncertainties, Reclamation plans to initiate an Adaptive Management Program. The concept of adaptive management is based on the recognized need for ongoing operational flexibility to respond to future monitoring and research findings and varying resource conditions. The objective of the Adaptive Management Program is to establish and implement long-term monitoring programs that will ensure that the Glen Canyon Dam is operated, consistent with existing law, in a manner that will protect, mitigate adverse impacts to, and improve the values for which the Glen Canyon National Recreational Area and the Grand Canyon National Park were established. According to Reclamation, long-term monitoring and research are essential to adaptive management. Reclamation believes that such an effort is needed to measure the performance of any selected EIS alternative. In this way, managers can determine whether the alternative is actually meeting resource management objectives and obtain an additional understanding of the resources’ responses to the dam’s operations.

Under Reclamation’s current proposal, the Adaptive Management Program, which would be under the direction of the Secretary of the Interior, would be facilitated through an Adaptive Management Work Group. The Adaptive Management Work Group, chartered under the Federal Advisory Committee Act, would include representatives from each of the EIS cooperating agencies, the basin states, contractors for the purchase of federal power, recreation interests, and environmental organizations. The work group would: • develop proposals for (1) modifying the operating criteria, (2)research under the long-term monitoring program, and (3) other mitigation actions as appropriate and facilitate technical coordination and input from interested parties.

The Adaptive Management Work Group would be supported by a monitoring and research center and a technical work group. The Monitoring and Research Center would manage and coordinate monitoring activities, research, and inventory programs and maintain a scientific information database. The technical work group would include technical representatives from federal, state, and tribal governments and their contractors. This work group would translate the policy and goals of the Adaptive Management Work Group into resource management objectives and establish criteria and standards for long-term monitoring and research. The independent scientific review panel would include scientific experts not otherwise participating in the long-term monitoring and research studies. The responsibilities of this review panel would include reviewing scientific study plans, resource reports, and scientific logic and protocols.

Most Key Interested Parties Support Reclamation’s Preferred Alternative for the Dam’s Operations, but Some Concerns Remain

Since December 1982, Reclamation has been studying the effects of the Glen Canyon Dam on various resources within the Glen and the Grand canyons. According to Reclamation, during this 14-year period, over $75 million was spent initially on the Glen Canyon Environmental Studies and then on the Glen Canyon Dam’s EIS. This research and analysis was aimed at providing sufficient information to recommend an operating plan for the dam that would permit the recovery of downstream resources while maintaining some level of hydropower flexibility. Still, after all this time and money, the process of selecting a preferred alternative involved not only scientific evidence but also trade-offs and compromise. This occurred because no one alternative could maximize benefits to all resources and because the impacts of some of the flow alternatives remain uncertain. Nevertheless, over 83 percent of the key interested parties who responded to our survey support Reclamation’s preferred alternative as a good starting point for the future operations of the Glen Canyon Dam. In addition, many respondents supported the process used to develop the Glen Canyon Dam’s EIS. However, while expressing their support, some organizations still had concerns about the final EIS.

Reclamation’s Process for Selecting a Preferred Alternative

“The Glen Canyon Dam EIS was a lengthy, complex process with many individuals and interests involved. It is safe to say that the preferred alternative will not completely satisfy any one group, however it represents a balance of interests and a reasonable starting point for future dam operations.”

Another factor that the EIS team considered was that some affected resources were renewable, while others were viewed as nonrenewable. They avoided recommending an alternative dam-operating procedure that would result in significant loss of any existing nonrenewable resource and tried to minimize the adverse impacts to most renewable resources. They eliminated the No-Action, Maximum Powerplant Capacity, and High Fluctuating Flow alternatives from consideration as a preferred alternative because the data indicated that while these alternatives were beneficial to hydropower, they would either increase or maintain conditions that result in adverse impacts to nonrenewable downstream resources.

The EIS team also eliminated the Year-Round Steady Flow alternative from consideration as the preferred alternative. This alternative exhibited the highest probability for net gain in riverbed sand, had the largest potential for expanding riparian vegetation, and received the highest ranking among all alternatives for white-water boating safety benefits. However, the EIS team believed that the alternative probably exceeded sediment protection requirements for long-term management and would result in the lowest-elevation sandbars. The team was also concerned that a completely stable flow alternative would permit vegetation to adversely affect camping beaches and over time reduce the value of wildlife habitat. In addition, a stable flow may increase the negative interaction between native fish and predator and competitor nonnative fish. Finally, the team eliminated this alternative because they believed that it did not provide benefits that could not be provided by other alternatives, yet it would cause large adverse effects to hydroelectric power generation.

Of the remaining alternatives, the Existing Monthly Volume Steady Flow alternative was eliminated for reasons similar to those discussed for the Year-Round Steady Flow alternative. The Low Fluctuating Flow alternative was eliminated to reduce redundancy—Reclamation considered the Modified Low Fluctuating Flow alternative an improved version of the Low Fluctuating Flow alternative.

The EIS team considered the impacts associated with the three remaining alternatives (Moderate Fluctuating Flow, Modified Low Fluctuating Flow, and Seasonally Adjusted Steady Flow), although they were substantially different from the effect of the No-Action alternative, to be very similar in their assumed benefits to most downstream resources. Reclamation’s former NEPA Manager for the Glen Canyon Dam’s EIS advised us that from an ecosystem perspective, sediment was identified as the key resource in the selection of a preferred alternative. Riverbed sand and sandbars were the sediment resources of primary interest affected by riverflows below the dam. For sandbars to exist, sufficient amounts of sand must be stored on the riverbed. Because the dam traps 90 percent of the sediment, the sand supply is currently limited to whatever is contributed by downstream tributaries and hundreds of side canyons. Of equal concern is the river’s capacity to transport sediment. Riverflows must be large enough to move and deposit sediment but not so large as to carry the sediment out of the canyon ecosystem. Frequent high flows, either from floods or large daily fluctuations, can transport greater amounts of sand than are contributed, causing a net decrease in both the amount of stored riverbed sand and the size of sandbars. Water release patterns modify the natural process of sandbar deposition and erosion. Rapid drops in the level of the river drain groundwater from sandbars, thus accelerating sandbar erosion. The EIS team concluded that any of these three alternatives were very similar in their assumed benefits to most downstream resources.

The effects on native fish did, however, vary among the three remaining alternatives. The Moderate Fluctuating Flow alternative provides potential minor benefits to native fish over no-action conditions. The benefits from the Seasonally Adjusted Steady Flow alternative were uncertain given the improvement in habitat conditions that this alternative would provide for predator and competitor nonnative fish. The team also determined that seasonally adjusted steady flows would create conditions significantly different from those under which the current aquatic ecosystem had developed since the construction of the dam. Finally, for hydropower, the team determined that the Seasonally Adjusted Steady Flow alternative would have the highest economic cost of any alternative, estimated at about $124 million annually. Ultimately, the EIS team decided to recommend the Modified Low Fluctuating Flow for the preferred alternative in the draft EIS. The members believed that this alternative would create conditions that permit the recovery of downstream resources to acceptable management levels while maintaining a level of hydroelectric power flexibility. The EIS team presented this recommendation to the cooperating agencies. Most cooperating agencies concurred, and the group recommended that this alternative be adopted by Reclamation. The draft EIS was issued by Reclamation in January 1994 with the Modified Low Fluctuating Flow identified as the preferred alternative.

After the draft EIS was provided for public comment but before the issuance of the final EIS, Reclamation changed two parameters of the preferred alternative. Specifically, the draft EIS’ preferred alternative had a maximum release level of 20,000 cfs and a maximum upramp rate of 2,500 cfs per hour. In the final EIS, Reclamation modified the preferred alternative to provide a maximum release level of 25,000 cfs and a maximum upramp rate of 4,000 cfs per hour. The primary reason for these changes was to benefit hydropower. The preferred alternative presented in the draft EIS had the same maximum release rate and upramp rate as the interim operating criteria. Reclamation stated that the interim operating criteria were based on the results of phase I of the Glen Canyon Environmental Studies and professional judgment and were designed to be environmentally conservative over the interim period. With the benefit of the additional phase II results of the Glen Canyon Environmental Studies and EIS impact analyses, Reclamation stated that the upramp rate and maximum flow criteria were found to be overly conservative for the long term and that the two changes would not cause adverse impacts to downstream resources. As a result, with the concurrence of the cooperating agencies, the preferred alternative was modified in the final EIS.

In July 1995, Reclamation issued a document entitled Flow Modifications to the Glen Canyon Dam Environmental Impact Statement Preferred Alternative. Those who commented on that document expressed concern that no studies on the specific upramp and maximum flow criteria had been conducted. In October 1995, Reclamation issued a new report entitled Assessment of Changes to the Glen Canyon Dam Environmental Impact Statement Preferred Alternative from Draft to Final EIS. This report provided a more detailed and focused assessment of the impacts associated with the increased upramp rate and maximum flow criteria. While acknowledging that no new studies were conducted, Reclamation pointed out that the same was true for the parameters of the interim flows when they were selected and implemented. Furthermore, Reclamation stated it was possible to determine the effects of these changes by using the extensive amount of knowledge gained from both phase I and phase II of the Glen Canyon Environmental Studies. Reclamation concluded that the analyses were fully adequate to justify the change.

Support for Preferred Alternative Is Significant

The respondents to our survey of key parties interested in the Glen Canyon Dam’s EIS overwhelmingly supported Reclamation’s preferred alternative—the Modified Low Fluctuating Flow operating regime. We surveyed 37 key organizations and individuals about whether they support the preferred alternative and what, if any, remaining concerns they may have about implementing this alternative as the future operating plan for the Glen Canyon Dam. Our judgmental sample included federal and state resource agencies, American Indian tribes, water and power suppliers and users, and environmental groups. Specifically, Reclamation identified 23 of these organizations and individuals as providing the most substantive comments on the draft EIS. We excluded David Marcus from our survey analysis because he had commented on the draft EIS as a consultant to American Rivers and preferred to provide us with his comments through that organization. In addition, we surveyed any other organizations that were considered to be cooperating agencies in the development of the impact statement as well as other key interested parties. We also queried the seven Colorado River Basin states: Arizona, California, Colorado, Nevada, New Mexico, Utah, and Wyoming.

Over 83 percent (25 of 30) of the respondents to our survey supported the preferred alternative. Of the five remaining respondents, three organizations stated that they had no position on the issue, while two, the San Juan Southern Paiute Tribe and the Grand Canyon River Guides, believe that the current interim flows would be more protective of resources and, as such, consistent with the intent of the Grand Canyon Protection Act. Table 3.1 provides details on whom we surveyed and their response, if any.

Respondents Also Support Reclamation’s EIS Process

Many respondents to our survey supported the process used by Reclamation to complete the EIS. In fact, many respondents commended Reclamation for its efforts to produce a comprehensive EIS. For example, the National Park Service stated that the EIS process was directed very well by Reclamation and that alternatives for the operation of the dam were fully explored. American Rivers, an environmental interest group, stated that the EIS is a high-quality document that reflects a process that was exemplary in its scope, thoroughness, and overall achievement. The Grand Canyon Trust stated that the EIS represents a significant and productive effort to understand the complexities of the river’s ecosystem below Glen Canyon Dam and to include broad participation by the public and parties vitally interested in the issue. They further stated that in addition to increasing the scientific understanding of the Colorado River system, a great deal of trust and good faith were created between traditionally contentious interest groups. The Navajo Nation stated that overall, they were very pleased with the EIS process, citing that Native American concerns were taken into account by Reclamation and that the affected tribes had real input into the development of the EIS.

Several Concerns Remain About the Implementation of the Dam’s New Operating Procedures

While respondents to our survey were generally positive about the selection of a preferred alternative and the process used by Reclamation to develop the EIS, some were still concerned about the preferred alternative and the Glen Canyon Dam’s final environmental impact statement. These concerns focus on the manner in which compliance with the Endangered Species Act will be achieved, the economic impact of reducing the Glen Canyon Dam’s hydroelectric power capacity, the lack of consideration in the EIS of other causes of downstream adverse impacts other than water releases from Glen Canyon Dam, the simultaneous changing of two of the dam’s operating parameters very late in the EIS process, the adequacy of the flood frequency reduction measures, the need for selective withdrawal structures, and issues related to adaptive management, including future research and monitoring.

The U.S. Fish and Wildlife Service supports the preferred alternative as modified by its reasonable and prudent alternative. FWS’s biological opinion expressed concern that the preferred alternative recommended flows would likely jeopardize the continued existence of two endangered species, the humpback chub and the razorback sucker. The biological opinion’s reasonable and prudent alternative would modify the preferred alternative with seasonally adjusted steady flows about 25 percent of the time. FWS and Reclamation agreed to categorize these flows as experimental, or research flows, so that studies could be conducted to verify an effective dam-operating plan and to include those flows with another element of the reasonable and prudent alternative, adaptive management. However, there are concerns on the part of the Colorado River Energy Distributors Association, which represents over 140 nonprofit utilities that purchase power from the Western Area Power Administration (WAPA), that the implementation of endangered fish research flows will proceed regardless of the outcome of the Adaptive Management Program. The association strongly supports the EIS preferred alternative as a reasonable point to begin modified dam operations and adaptive management. However, the association also believes that an important part of the adaptive management process is that if an analysis of a research proposal indicates an inappropriate risk to the endangered fish or other resource, the Secretary could decide not to pursue this element of the preferred alternative. As such, the association objects to the language in the final EIS and the final biological opinion that indicates that the research flows will go forward regardless of the outcome of the adaptive management research design and risk assessment.

The Colorado River Energy Distributors Association and the Salt River Project, an agricultural improvement district that provides electrical service to various counties in the state of Arizona, are concerned that the economic cost of reducing the hydroelectric power capacity of the Glen Canyon Dam is understated in the EIS. Both the association and the Salt River Project believe that the preferred alternative does not adequately address the economic cost to power users of research flows. In addition, the Salt River Project believes that the EIS does not analyze the full economic impact of the preferred alternative on Salt River and its customers and on WAPA and its customers, resulting from WAPA’s being unable to fulfill its obligations under an exchange agreement. The exchange agreement obligated Salt River to build and operate power generation facilities near customers in Colorado and New Mexico and to deliver the power produced by those facilities to WAPA to serve those customers. In exchange, WAPA was obligated to deliver a like amount of power to the Salt River Project from the Glen Canyon Dam.

WAPA stated that the EIS assumes that the dam’s operations (water releases) are the only cause of the adverse impacts on the downstream resources and that, therefore, changing the dam’s operations is the only technique or method available for managing and enhancing those resources. WAPA believes that other causes of downstream impacts include lack of sediment, cold water temperatures, nonnative fish species, and human usage. Accordingly, they believe that changing the operations at Glen Canyon Dam is not the only, or necessarily the best or lowest-cost, means of achieving positive resource changes. WAPA believes that a more holistic approach to the management of the downstream resources should be taken and supports the investigation of both operational and nonoperational management techniques, practices, and programs. Although WAPA supports the preferred alternative, it stated that the concepts of pumping sand, protecting beaches with native materials, augmenting sediment, managing vegetation, restricting human use, restricting raft moorings, reducing the competition for native fish, developing new tributary habitats for native fish, and using a reregulation dam (build another dam below the Glen Canyon Dam to regulate river flow) are all valid management techniques that merit detailed investigation and consideration.

Several environmental and recreational organizations, although supporting the preferred alternative, were concerned that Reclamation changed certain parameters of the preferred alternative very late in the EIS process. Specifically, the draft EIS’ preferred alternative had a maximum release level of 20,000 cfs and a maximum rate of increase (upramp rate) of 2,500 cfs per hour. In the final EIS, Reclamation modified the preferred alternative to allow for a maximum release level of 25,000 cfs and a maximum upramp rate of 4,000 cfs per hour. Two basic concerns exist about this change: (1) the higher parameters were substituted in the final EIS without adequate scientific evidence that such flows would not negatively affect the downstream resources of the Glen and Grand canyons and (2) two parameters were changed simultaneously, which could compromise the ability to scientifically monitor and assess the future impacts of these flow parameters in the proposed adaptive management framework. Reclamation believes that it has adequately addressed both of these concerns by conducting an assessment of the proposed changes. Some agencies, including the Wyoming State Engineer’s Office, America Outdoors, American Rivers, and the Sierra Club Legal Defense Fund still believe that adequate specific scientific testing was not done to fully evaluate the effect of changing these flow parameters. However, these groups still support the preferred alternative at this time because of Reclamation’s proposed Adaptive Management Program.

The New Mexico Interstate Stream Commission believes that the spillway gates on the Glen Canyon Dam must be increased in height by about 4.5 feet to add the flexibility to accomplish flood protection without reducing the water supply available to the Upper Colorado Basin. The Commission, which supports the preferred alternative, also believes that the selective withdrawal outlet proposal for Glen Canyon Dam has not been adequately justified; the estimated cost of $60 million needs to be arrayed against the resulting benefits; and an assessment needs to be made of the potential adverse impacts associated with increasing water temperature.

Future monitoring and research efforts were a concern of several groups, including federal agencies, Native American tribes, and an environmental group. For example, American Rivers urged Reclamation to do everything in its power to ensure that an effective Adaptive Management Program be in place or sufficiently delineated in scope and substance and that a specific long-term monitoring program be identified that will quantify any impacts before the proposed flow changes are implemented.