Colorado River Ecology and Dam Management Proceedings of a Symposium May 24-25, 1990 Santa Fe, New Mexico (1991) / Chapter Skim
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Glen Canyon Environmental Studies Research Program: Past, Present, and Future
Glen Canyon Environmental Studies Research Program: Past, Present, and Future
Pages 239-253
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From page 239... ...
These inadequacies were partially due to poor planning and research design, but also to the high water conditions during the research period. The results of the initial phase, GCES I, were reviewed by a National Research Council committee which recommended, along with the Glen Canyon Environmental Studies Executive Review Committee, that further studies be done on the effects of dam operations on the Canyon resources.
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From page 240... ...
However, environmental concerns arising in the 1970s raised questions about the Bureau's water management decisions, for example, those dealing with operations of Glen Canyon Dam. Thus the Bureau established the Glen Canyon Environmental Studies to develop data that could be used to malice decisions on the operating criteria of the dam and the environmental and legal requirements related to management of the Colorado River.
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From page 241... ...
The NRC review and recommendations were a critical input to the future development of a research program on the impacts of the operations of Glen Canyon Dam. REVIEW OF GCES I BY THE NRC COMMITTEE The 1986-1987 review of GCES I by the NRC, Water Science and Technology Board, Glen Canyon Environmental Studies Committee (National Research Council, 1987)
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From page 242... ...
· For operations: initiate a feasibility study of changes in dam operations and non-operation alternatives, and consider all management options. INITIAL INTEGRATION PHASE OF GCES II If GCES II was going to contribute to our understanding of the Grand Canyon system, it had to develop a program that regarded the system as an integrated whole, a point emphasized by the NRC committee.
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From page 243... ...
The controlling variables were divided between those that are regulated directly by the dam and its operations, and those that are regulated by other factors in addition to dam operations. Dam dependent variables were such factors as flow volume, flow fluctuations, ramping rates, and water quality and temperature.
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From page 244... ...
DEVELOPMENT OF SHORT-TERM RESEARCH HYPOTHESES AND EXPERIMENTAL DESIGNS The next step in development of the short-term research program was development of short-term research questions that would lead to hypotheses, again using an iterative process among Grand Canyon researchers and resource managers. These questions were related to general issues dealing with operations and management of Glen Canyon Dam and other resources, a condensation of the control and response variables identified in an earlier iteration of the research program.
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/ _ _ 1990 1991 1992 1993 1994 1995 1996- / / / / / Mitigation No change alternat. Evaluation Variable intake Structure Reregulation Dam Beach Stabiliz.
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From page 247... ...
. DEVELOPMENT OF CONTROLLED RESEARCH DISCHARGES FROM GLEN CANYON DAM Answering the questions and developing response curves and models for the resources in the Canyon require conditions more controlled' than the widely fluctuating daily (and seasonally)
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From page 249... ...
Q-15.1. Are there any non-use benefits that are attributable environment in the Canyon below Glen Canyon Dam and if so would these values be affected by changes in dam operations?
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Q-5.1. How do discharge fluctuations, minimum discharges and rates of change of fluctuating discharges affect foraging success of wintering bald eagles?
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Constant 28 2 1216 2630 1317 271 1115 2529 8 12 13 172731 June July August September October November December Constant Flows _ Minimum Flows ~ Maximum Flows High High High High High High High 31 1014 2428 7 11 1822 (1 5,000 cts) Constant 2 6 1620 303 271 1115 2526 January February March April May June July ~ Constant Flows _ Minimum Flows t~ Maximum Flows FIGURE 11-4 Research discharge flow schedules for 1990 and 1991.
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From page 252... ...
Models of other processes, such as sediment transport, eddy dynamics, and humpback chub population dynamics, require a much longer period of data collection than that allotted under the short-term research program, even with controlled, research discharges from the dam. The short-term research data, along with those data generated under GCES I, can only be used, in areas where long-term data are needed, to guide decision making in the EIS process.
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From page 253... ...
1988c. Glen Canyon Environmental Studies, Executive Review Committee final report.
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