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Introduction
In 1956 Congress passed the Colorado River Storage Project Act, which authorized construction of Glen Canyon Dam on the Colorado River above Lees Ferry. In identifying purposes for Glen Canyon Dam, the Act specifically mentions requirements for the storage of water for beneficial use, reclamation of arid and semi-arid lands, control of floods, and, as an incident of other specifically mentioned purposes, the generation of hydroelectric power. The Bureau of Reclamation, which assumed responsibility for managing the Dam following its completion in 1963, developed a management plan that reflected the legislative statement of purpose. The operating rules for the Dam were based upon two principles: (1) scheduling of annual and seasonal releases as necessary to deliver water for consumptive use, and (2) scheduling of daily and monthly releases in such a way as to maximize revenues from hydroelectric power production.
The Colorado River Basin Project Act of 1968 broadened the purposes for operation of the Dam by referring not only to storage and delivery of water, but also to water quality, outdoor recreation, and fish and wildlife; the 1968 Act again listed power production as a purpose incident to the other purposes. Even more recently, the 1992 Grand Canyon Protection Act has specifically mentioned the need to “mitigate adverse impacts to, and improve the values for which Grand Canyon National Park and Glen Canyon National Recreation Area were established, including, but not limited to natural and cultural resources and visitor use.”
The Bureau's principles for operation of Glen Canyon Dam remained essentially unchanged from 1963 into the 1980s, even though legislation had broadened the purposes of operation. As a result, critics charged that the Bureau's operating rules for Glen Canyon Dam were excessively focused on water delivery and power production. However, modification of the operating rules was inhibited partly by lack of information about the effects of operations on recreation, aquatic life, culturally important sites, and
physical attributes of the river channel. The need for information on these resources led the Bureau of Reclamation to authorize the Glen Canyon Environmental Studies (GCES) in 1982. The Glen Canyon Environmental Studies have continued, with support from the Bureau of Reclamation, to the present.
As the GCES program matured, the Bureau of Reclamation authorized substantial expansion of its scope, which originally was limited to the immediate surroundings of Glen Canyon Dam. By 1986 it was clear that GCES must extend at least over the 255 miles from the forebay of Lake Powell to the upper end of Lake Mead. The GCES also expanded conceptually to include such subjects as cultural resources of Native Americans and non-use values as applied to the Colorado River in the Grand Canyon. With its broader objectives, the GCES reached a peak expenditure of $11-$12 million per year in 1990 to 1993.
The majority of GCES work has been conducted by employees of the Bureau of Reclamation, the National Park Service, the U.S. Fish and Wildlife Service, the Western Area Power Administration, the Arizona Game and Fish Department, and the U.S. Geological Survey. In recent years, Indian tribes and a few consultants have also played a significant role in GCES.
ROLE OF THE NRC REVIEW COMMITTEE
In 1986 the Bureau of Reclamation requested that the National Academy of Sciences, through the National Research Council's Water Science and Technology Board, conduct a review of the Glen Canyon Environmental Studies and provide advice on alternative operation schemes for Glen Canyon Dam. Since 1986, the NRC committee has produced numerous short reports as well as an extensive analysis of GCES Phase I (NRC, 1987) and a symposium volume that was designed to summarize ecological, legal, physical, chemical, and biological knowledge of the Colorado River in the Grand Canyon as of 1990 (NRC, 1990). The committee' s current scope of work includes: (1) assessment and formulation of recommendations for the research strategy of the GCES and, more generally, for the application of scientific principles to the management program for the Colorado River below Glen Canyon Dam; (2) assistance to GCES in the development of a long-term monitoring program within the zone of influence for operations of Glen Canyon Dam; and (3) recommendations for the development of criteria to be used in the protection of the riverine ecosystem in the Grand Canyon below Glen Canyon Dam, within the constraints of operating criteria for Glen Canyon Dam.
In 1989 the GCES assumed new significance as a result of the Interior Secretary's decision to authorize an Environmental Impact Statement (EIS) on the operation of Glen Canyon Dam and a concurrent EIS of the production and marketing of power from
Glen Canyon Dam. Because the GCES was the only broad-ranging source of current scientific information on the Colorado River below the Dam, it provided much of the technical support for the multi-agency team that prepared the Draft Environmental Impact Statement under direction of the Bureau of Reclamation.
Even prior to the authorization of the two Draft Environmental Impact Statements, which were released in January 1994, the Bureau of Reclamation had acknowledged the need for long-term monitoring on the Colorado River between Glen Canyon Dam and Lake Mead. The need for such a program was reinforced by the Grand Canyon Protection Act of 1992, which explicitly requires knowledge and protection of the natural resources of the canyon as impacted by water supply and power production.
As the Draft EIS (DEIS) on operations was being prepared, the Bureau of Reclamation instructed the Manager of the GCES to create a draft plan for long-term monitoring of environmental resources that would be affected by the operation of Glen Canyon Dam. The GCES Program Manager then asked the NRC committee to sponsor and organize a workshop on long-term monitoring. The purpose of the workshop was to provide input to the GCES senior scientist, who would be drafting the GCES long-term monitoring program plan, from a variety of people with experience in long-term monitoring. The workshop was held in October, 1992. The NRC committee invited 50 participants, all of whom were selected on the basis of their direct experience with long-term monitoring programs or with the state-of-the art-in measurement of environmental variables of concern below Glen Canyon Dam. A transcript of workshop discussions was forwarded to the GCES Program Manager and the GCES Senior Scientist with the understanding that it would be used in developing the long-term monitoring plan, which is to be included in the DEIS.
Part of the NRC committee's charge is to review the draft monitoring plan, which is reproduced in this report as Appendix B. The review includes all aspects of the draft, including scope of work, protocols for acquisition and archiving of environmental data, organization, justification, and implementation. The review deals first with individual segments of the plan, and then draws general conclusions.
