Below is the uncorrected machine-read text of this chapter, intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text of each book. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.
1 1 Glen Canyon Environmental Studies Research Program: Past, Present and Future DUNCAN T. PAULSEN, Arizona State University, Tempe, Arizona ABSTRACT: The present research program within the Grand Canyon is a result of inadequacies of the initial Glen Canyon Environmental Studies. These inadequacies were partially due to poor planning and research design, but also to the high water conditions during the re- search 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 Com- mittee, that further studies be done on the effects of dam operations on the Canyon resources. This led to establishment of GCES II which has gone through an iterative process to develop testable hypotheses on the effects of dam operations and other activities in the Canyon. Experi- mental designs are being developed for research, and controlled re- search discharges from the dam scheduled for the next 2 years. This short-term research program has been developed to address the data needs of the EIS which will select a dam operations alternative for the future. It is recognized that this short-term research program will not thoroughly explain the functions and responses of resources within the Canyon, and that a long-term research and monitoring program is nec- essary for evaluation of the EIS-selected alternative. BACKGROUND: GLEN CANYON ENVIRONMENTAL STUDIES I, 1982-1987 The Glen Canyon Environmental Studies (GCES I) were initiated in 1982 in response to potential changes in the Bureau of Reclamation's manage- 239
240 COLORADO RIVER ECOLOGY AlID DAM MANAGEMENT ment of water flowing in the Colorado River through Glen Canyon Dam because of upgrading of the dam's eight generators. The early history of the Bureau was one of water storage for control of down stream flows, prima- rily for irrigation. However, environmental concerns arising in the 1970s raised questions about the Bureau's water management decisions, for ex- ample, 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 Colo- rado River. GCES I, as a multi-agency effort, produced 33 technical reports based on 4-5 years of study. These reports were integrated into a composite final report (USDI l98Sa) that addressed the question of how much impact the present operations of Glen Canyon Dam had on the Grand Canyon ecosys- tem, including downstream human activities. The executive summaries of the technical reports were also combined into a single volume for ease of reference (USDI, 1988b). The technical reports were presented in four ma- jor groups, sediment, biology, recreation, and dam operations. The infor- mation from each of these groups presented various levels of impact on resources resulting from dam operations. GCES I was able to make a few significant statements. These were: Some aspects of the operation of Glen Canyon Dam have substantial adverse effects on downstream environmental and recreational resources. Flood releases cause damage to beaches and terrestrial resources. Un- der current operations of the dam and lake storage, flood releases will occur in about one of every four years. Fluctuating releases primarily affect recreation and aquatic resources. Modified operations could protect or enhance most resources. In the end, it was realized that GCES I research had occurred during an abnormal high water period and that the understanding of the relationships between dam operations and downstream resources were incomplete. DEVELOPMENT OF GLEN CANYON ENVIRONMENTAL STUDIES II RESEARCH PROGRAM In 1987, when GCES I had ended, there was concern that the research program had not developed the information base necessary to evaluate the operations of Glen Canyon Dam. Although the Glen Canyon Environmental Studies Executive Review Committee had used the results of GCES I to indicate that Glen Canyon Dam was causing an impact downstream, it did not totally endorse some of the conclusions of GCES I and thought that more research was necessary, especially on impacts of low-fluctuating flows,
THE GCES PROGRAM: PAST, PRESENT, AND FUTURE... 241 endangered species, and power/recreation economics (USDI 1988c). The request for more research under normal dam operating conditions for these limited areas was supported by the Assistant Secretaries of Interior for Water and Science, and Fish, Wildlife and Parks in June 198g. At the time GCES I was being consolidated into a final report, a commit- tee of the National Research Council's, Water Science and Technology Board was funded by GCES I to review the whole program from research initiation through the final integrated report. The report from this commit- tee was completed at the same time as the Executive Review Committee's report to the Secretary of Interior. 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 Tech- nology Board, Glen Canyon Environmental Studies Committee (National Research Council, 1987) addressed inadequacies of the research program, but also pointed out that GCES I had produced much valuable data that would be useful to continued studies of the Grand Canyon ecosystem and the operations of Glen Canyon Dam. Some of the major criticisms pre- sented by the NRC committee include: (1) insufficient attention to early planning, review of existing knowledge, and careful articulation of objec- tives, (2) lack of distinction between science and management of the project, with a need for a senior scientist and scientific oversight group established at the beginning of the studies, (3) lack of soliciting the best scientific talent to do the research, (4) inadequate consideration of economic conse- quences of various management options, and (5) uncertain conversion of research results into management options. The committee also stated that ecological understanding of the system is paramount to making defendable management decisions, the understanding in this case requiring a sustained research effort because the river is in disequilibrium and operational deci- sions will require continuous monitoring to ensure the desired environmen- tal effects are being achieved. Other pertinent points raised by the NRC committee were presented un- der the various resources being studied in the Canyon. These include: For aquatic resources: evaluate the quality of water at various potential release levels in Lake Powell, include algal and invertebrate productivity in future studies, perform focused studies on sediment movement, and develop process-oriented models to understand sediments, water temperatures, nutri- ent concentrations, and economic and power production. For terrestrial biology: establish links to river productivity, and antici- pate heterogeneity and match methods to temporal and spatial scales.
242 COLORADO RIVER ECOLOGY AND DAM MANAGEMENT · For sediment and hydrology: study tributary processes, include empiri- cal approaches and modelling in hydrological studies, link sediment studies to hydrological and biological monitoring, and institute geomorphic studies to supplement hydraulic studies. · For recreation: clarify cost/benefit tradeoffs between power generation and recreation, broaden recreational constituencies, and avoid use of hypo- thetical flows. · 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. For example, beach or sand bar aggradation or degradation is not only important as part of a sediment dynamics study in the canyon, but it also is associated with availability of backwaters for fish recruitment, or beaches for recreational camping. The necessity of incorporating all of the activities and resources in a comprehensive research plan required some form of integration of researchers from the various disciplines studying the Grand Canyon or other similar large river systems. In July of 1989, over thirty five scientists and resource managers took a 2-week river trip through the Canyon with the explicit purpose of develop- ing research needs for better understanding the Canyons ecological pro- cesses and the human activities that impact and respond to these processes. Working within the actual geographical setting enhanced the interchange among the participants. There were those who came on the trip to espouse a single concept or to protect a resource or preconceived idea. Fortunately, the grandeur of the Canyon opened most minds and allowed a balanced exchange amongst individuals from different backgrounds. There were two goals of this river trip. The first was to develop research questions by discipline, for example, what are the processes that control eddy dynamics? The second was to have each discipline indicate the infor- mation it might need from another discipline for a better understanding of processes and responses within its area of interest. By August 1989 a first draft research program had been developed. This was the beginning of an iterative process with the final goal being a defini- tive research program with hypotheses and research plans. The August draft research program was considered too broad by most participants. Too broad in the sense that it addressed most researchable problems in the Canyon and was not specifically related to understanding the impacts of the operations of Glen Canyon Dam. Some participants,
THE GCES PROGRAM: PAST, PRESENT, AND FUTURE... 243 however, thought the August draft could have gone farther toward a total ecosystem study of the Canyon based on the concept that in order to under- stand the impacts, the total system should be thoroughly understood. The initial research program for GCES II gave structure to identifying the research needs. This was partitioned into three parts: (1) identification and understanding of controlling variables within the system, (2) identification of characteristics for crucial habitats of significant (high priority) resources or resource uses, and (3) understanding the magnitude of the influence of the controlling variables, in static or changing modes on the significant resources or uses. Research guidelines for GCES II were established at this point. These included (1) problem identification, (2) literature search, (3) problem refine- ment, (4) research design, (5) research and analysis, and (6) monitoring. 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. Variables not associated directly with dam operations were such factors as canyon geomorphology, sediment input and dynamics, vegetation dynamics, nutrient dynamics, as well as anthropogenic variables . . . . such as recreat~ona activities. Significant resources for which crucial habitat or environmental require- ments need to be identified for research needs included: fish (exotic and native, especially endangered species), aquatic food base, terrestrial vegeta- tion, wildlife (especially threatened and endangered species), recreation, cultural resources, water storage, and power production. By expanding on the definitions of controlling variables and resource re- quirements, information gaps were identified that would lead to research needs. For example, for the dam-dependent variable "flow," the relationship between the flow from the dam and flows at different points downstream are unknown, or for the non-dam variable "sediment input," the contribution of sediment from the many tributaries feeding into the Grand Canyon is unknown. Ex- amples of gaps for resource requirements are: for fish, habitat requirements for life stages and reproduction; or for cultural resources, requirements for stability of archaeological sites near or below the high-water line. The final phase of the first research program presentation was an integra- tion of controlling and response variables. This took the form of (1) inter- action among controlling variables such as flow and sediment dynamics, and (2) resource response to controlling variables, such as fish habitat as a function of flows. After review of the first draft of the GCES II research program, it was necessary to condense the program to points that might be useful in deci- sion making in the managing the dam as well as other resources in the Canyon. This became a necessity because decisions on dam operations
244 COLORADO RIVER ECOLOGY AND DAM MANAGEMENT were now tied to an EIS, as of August 1989, and the time frame for infor- mation gathering was initially set at a 2-year limit, a major reduction over an earlier, 4-plus-year limit. To convince decision makers that many of the resources and processes presented in the first draft of the research program were part of decision making, that is, they connected the controlling vari- ables to the crucial resource responses, a complex system diagram was prepared (Figure 11-1) showing the various steps and processes between an input or control variable and the desired state of a crucial variable. After reviewing this figure, it becomes obvious that 2 years or less is an insuffi- cient time frame to critically evaluate, through legitimate research, all re- sponses between input (controlling variables) and the ultimate state of re- source or use. At this point, the Glen Canyon Environmental Studies research program had reached a stage that required development of a double pronged ap- proach. There was a need for a short-term research program that would address the problems identified in the development of the initial research program in order to achieve a data base that could be used to evaluate the environmental consequences of the EIS alternatives. There was also a need to develop a long-term research and monitoring program to enable a more thorough development of ecosystem process models and to initiate a moni- toring program that would be used to evaluate the dam operation alternative selected through the EIS process. This long-term program is essential to the success of the studies within the Grand Canyon, because the time necessary to gain a high degree of confidence in the research models and results is much greater than the time allotted for the short-term component of the research program (Figure 11-2~. This does not mean that the short-term research program should have been abandoned, but that our confidence in the results from the short-term program will improve with the addition, over . ~ . ~ . time, ot more Information. 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 hypoth- eses, 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. The general headings of these issues were: (1) Effects of Dam Operations, (2) Effects of Recreation, (3) Effects of Economic Balances, and (4) Potential Future Mitigation Alternatives in Addition to Modification of Discharge Criteria.
245 L~ CD ' Cl) C~ ~ 3m cn U] CI: cl) L~ cn U) U] o ~: c z ~: CO UJ J m ~: > LL CO Z C~ o Q CD LU J U) <: UJ ~=r m U] X ~ J ~ O CD CE .5 o - c ~ ~ .C -' +~ ~ _ . m ' c: ci \\ ~ ~ m~ ~ ~ c ~ ~ _ _ m ~ ~ i T I ° om ~ c ~ , _ ~ ci ca a) + a) c =, C) - .o C5 3 ~ + _, . C o CL, C) C~ CD C~ ._ W^= a) ~ C~ a,~ ~ ~ ~ ~ Ct _ C C) LL D c =m ~° '=!= :2 °c'=~' .0 / ~-0 ~ ~ ~ ~ , = _ 1 ~ 3 U. ca o U) o C) o v u, · i, ~ j o E ,, ~ C \ \ .' ~ C o 3 ~ CO 1/ - = = 0 ~, ·= ~ o D o <~ c7~ ~ D ~ //~3 ~U LC U, - V, U, · (V o _1 U~ C) O > _ Ct ~ V
246 COLORADO RIVER ECOLOGY AND DAM MANAGEMENT Flow Routing Model (USGS) Sediment Transport Model (USGS) Eddy Dynamics Model (USGS) Beach Erosion Models (NPS) Beach Surveys (USGS) Trophic Dynamics Models (AGF,USGS) Trout Stranding (AGF) Trout Population Dynamics (AGF) Eagle/Trout Dynamics (BR,AGF) Humpback Chub Conserv. Meas. (FWS, AGF, BR) Cultural Resources Responses Recreation Response and Impact Models 1990 1991 1992 1993 1994 1995 1996-- / / / / / / / / _______-------? / ( x _ _ _ _ _ Lees Ferry Angler --------------X Access (BR subcont.) Economic Models --------------X (BR subcont.) / _ _ 1990 1991 1992 1993 1994 1995 1996-- / / / / / Mitigation No change alternat. Evaluation Variable intake Structure Reregulation Dam Beach Stabiliz. Sediment Augment. / = research initiated - - - - research ongoing or continued as monitoring ------- intensive research program X = data and analysis at stage to be useful to EIS, ( ? = data questionable whether useful to EIS FIGURE 11-2 Anticipated research schedule and data usability. )=incomplete
THE GOES PROGRAM: PAST, PRESENT, AND FUTURE... 247 The following listing of the short-term research questions (Table 11-1) were developed based on general justification and information needs state- ments. Research proposals addressing these questions have been prepared by scientists from different agencies, for example, US Geological Survey, National Park Service, Arizona Game and Fish Department, and the Bureau of Reclamation. Some of the economic and endangered fish species re- search will be done by non-agency scientists through development of pro- posals responding to Bureau of Reclamation "Request for Proposals" (RFPs). 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) discharge flows from Glen Can- yon Dam. Controlled research discharge flows are an obvious necessity. The duration of the controlled discharges should be sufficient for the sys- tem to reach an equilibrium with the discharge. A compromise was made to use a 2-week period, although most scientists agreed that a 4-week period was preferable. A dendrogram was used to determine the minimum number of research discharges (Figure 11-3~. These were then placed into a sched- ule to satisfy downstream water release requirements, and recreation and power network considerations (Figure 11-4~. The research discharges in- cluded not only controlled regular fluctuations, but also constant discharge flows (with volumes equivalent to fluctuating discharges), and normal operations fluctuating discharges (based on the same time period from 1989~. The only replication of controlled discharges are the first two in July 1990 and July 1991 (see Figure 11-4~. If three replications were run for each controlled discharge, the duration for each was increased to 4 weeks, and additional discharges were selected to better test all variables, the research discharge period would last approximately 18 years. This is obviously unacceptable to all concerned. The compromise, for the meantime, has been a composite period of approximately 6 months of controlled discharges. This, perhaps, is erring on the short side. Results from the research under- taken during the controlled discharges will be evaluated with this in mind. DEVELOPMENT OF LONG-TERM RESEARCH AND MONITORING NEEDS Any short-term study of an ecosystem as complex as the Grand Canyon is bound to be a failure if the research is viewed as the final answer to understanding the system. The short-term study explained above was de- veloped primarily to address potential EIS alternatives, not to fully under-
250 - _ V) 1 o C) o o o LO I I g g oo ~ . ~ cn a C~ s C: _ ~_ _ C) a cJ a CE ~_~ - 11 o . _ o , o o , o ~ C~ ~ A . _ I _ 0 cn a _ _ . ~ o _ g._ V ~ ~ o O J J O O g C~ - =)O3- _ I ~ . 1 o o o CM o o o CO _ a) - . _ Q . _ ~n a a) o J a c; .c =, .~) Q- a) - C) (~ ._ =,_ . _ _ O Q J a _ ._ =, I a _ ~ .' ~ JO ~= (15 ~ E ° 4 ~: o V C~ c) o V) C) - ;^ _4 Cd ._ x o ;> U, ~o ~s u, ~ - a ~4 - := - CD C) Ct C) U) ._ a C) ~a Pt 0 _ _ Cd o4 ~ O Ct a~ v a ~ O U, ~3 0D Cd , S V ~ .~
THE GOES PROGRAM: PAST, PRESENT, AND FUTURE... TABLE 11-1 Continued... 249 Q-ll.la. Does fishing activity, including boating, affect beach stability, especially in the Lee's Ferry reach? Q-ll.lb. What is the relationship between the trout population of the Lee's Ferry reach and fishing activities, especially catch and release or keep relationships? B. Effects of rafting and Camping Activities. Q-12.1. How does rafting and camping affect other Canyon resources, especially the sedi- ment volume of beaches? III. Effects of Economic Balances. A. Power Economics. Q-13.1. If creating a more stable environment in the Canyon below Glen Canyon Dam requires changes in power operations, what is the economic impact of these changes? B. Recreational Economics. Q-14.1. Are the economic benefits of downstream recreational activities as well as associ- ated tourism services (e.g., lodging, airlines, restaurants, etc.) affected by operations of Glen Canyon Dam? C. Non-use Economics. 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? to the maintenance of a stable IV. Potential Future Mitigation Alternatives in Addition to Modification of Discharge Criteria. A. Effects of "No Change" Altemative. Q-16.1. Are there any greater economic or environmental costs to the "no change" alterna- tive if compared to the other alternatives? B. Effects of Variable Intake Structures Q-17.1. If a variable intake structure is used on Glen Canyon Dam, what will be the effects of intake at various levels on the downstream system? C. Effects of A Reregulation Dam. Q-18.1. If a regulation dam were constructed in the Canyon some where between Glen Canyon Dam and Lee's Ferry, what would be the effects of the discharges from this dam on the downstream system? Q-18.2. What would be the impact of a reregulation dam on the Lee's Ferry reach if it is constructed in this reach? D. Effects of Beach Protection Devices. Q-19.1. Is it possible to mitigate the degradation of camping beaches in the Canyon due to dam operations using beach protection devices? E. Effects of Sediment Augmentation. No questions have been developed until methodology is identified.
248 COLORADO RIVER ECOLOGY AND Do MANAGEMENT TABLE 11-1 Outline of Short-term Research Questions for Analyzing Resource Responses. I. Effects of Dam Operations A. Effects of the Magnitude of Daily Discharge Fluctuations, Minimum Discharges, and Rate of Change (Ramping) of Fluctuating Discharges. Q-1.1. How significant are discharge fluctuations, minimum discharge and ramping in the degradation or aggradation of beaches? Q-2.1. Do discharge fluctuations, differences in minimum discharges, or different rates of change in daily discharges (ramping rates) interact withother uses and components of the Canyon to affect rates of sediment degradation? Q-2.1a. What is the relationship between the effects of recreational use of beaches and the magnitude in daily discharge fluctuations, daily discharge minima, or daily ramping rates? Q-2.1b. What is the relationship between the role of vegetation as a beach stabilizer and the magnitude of daily discharge fluctuations? Q-3.1. How do daily discharge fluctuations, minimum discharges or ramping rates influence the amount of sediment stored in or transported in the Canyon system? Q-4.1. How do discharge fluctuations, minimum discharges and rates of change of fluctuat- ing discharges affect trout? Q-4.1a. What is the relationship between the rate of stranding of trout and the magnitude of discharge fluctuations, minimum discharges, or the ramping rates? Q-4.1b. What is the relationship between behavioral activity of rainbow trout and the mag- nitude of daily discharge fluctuations, daily minimum discharges and ramping rates? Q-5.1. How do discharge fluctuations, minimum discharges and rates of change of fluctuat- ing discharges affect foraging success of wintering bald eagles? Q-5.la. What is the relationship between trout availability, trout access, bald eagle presence, bald eagle abundance or bald eagle foraging success in the mainstream or Nankoweap Creek and the magnitude of daily discharges? Q-6.1. How do dischare fluctuations and rates of change in fluctuating discharges affect the population dynamics (including short-term abundance of early life stages and potential preda- tion relationships) of native (especially the humpback chub) and introduced fish species in the mainstem Colorado, including main stem backwaters and the confluence of the Little Colorado? Q-7.1. How are water quality (nutrient availability and other characteristics), stream produc- tivity (of algae and macroinvertebrates), and import-export rates or organic matter to and from the Lee's Ferry reach influenced by the magnitude of discharge fluctuations, and the ramping rates? Q-8.1. How are recreational variables (angler safety and rafting safety, satisfaction, experi- ential quality and economics) influenced by the magnitude of seasonal or daily discharge fluctuations, minimum discharges or the ramping rates? Q-9.1. Are there sufficient camping beaches during maximum normal operations discharges from Glen Canyon Dam (i.e., 31,500 or 33,200 cfs) to satisfy the needs of the recreational rafting community based on the NPS acceptable carrying capacity of the Grand Canyon system? Q-10.1. Do dam operations (e.g., magnitude of stage, magnitude of discharge fluctuations and/or ramping rates) affect the stability of cultural resource sites along the river in the Grand Canyon? II. Effects of Recreation. A. Effects of Fishing Activities. Q-11.1. Does fishing activity, including boating, in the Lee's Ferry reach affect other Can- yon resources?
THE GOES PROGRAM: PAST. PRESENT, AND FUTURE... 30 u, ct o 20 c 15 lo Cal cC 1 0 I cn C] 25 High High 5 d~ o 3s r ct in o c ._ - L" 1 5 CO G I cn C] 30 25 20 10 251 Hign 1 4 ~ High (8,000 cfs Constant (1 1,000 cfs) 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. stand all of the processes going on within the Canyon. As a result, it has limitations, of which one of the most important may be misleading interpre- tation of data. This can be avoided only if those doing the interpretation recognize the limitation and place a wide band of uncertainty around their conclusions. EXPANSION OF THE SHORT-TERM RESEARCH PROGRAM To ensure an adequate understanding of the Grand Canyon ecosystem, the short-term research program must be continued in those areas for which
252 COLORADO RIVER ECOLOGY AND DAM MANAGEMENT long-term data is essential. Models and response curves can be adequately developed for some of the resources in a relatively short period of time, for example, some of the economic models and recreational responses. Models of other processes, such as sediment transport, eddy dynamics, and hump- back chub population dynamics, require a much longer period of data col- lection 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 pro- cess. This does not mean these data will not be useful, they will be useful with limitations. The need for an expanded research program can clearly be seen in Figure 11-2 which shows estimates of the time needed to generate useful informa- tion for a thorough understanding of the Canyon system. This information will be a necessary input into the understanding of the data generated from a long-term monitoring program, a program essential to evaluating the ac- curacy of the EIS decision-making process. LONG-TERM MONITORING A long-term monitoring program should be started along with the present short-term research program and should continue, along with the long-term research program, for some time after completion of the EIS. Monitoring is used to determine the state of resources as well as their response to existing conditions. Changes in the state of a resource indicates a beneficial or detrimental response to controlling variables, such as dam operations. It is the understanding of these changes for which the short and long term re- search data will be used. The long-term monitoring program should be organized in such a way as to assure valid determination of changes taking place in the Canyon. This means a regular schedule of measurements of both the sensitive and non- sensitive resources. Some resources, such as camping beaches, should be measured at least twice a year, while others, such as trout spawning and stranding, might be measured just during that season when the response is greatest. The resources to be monitored, as well as the timing and location of monitoring, should be determined from data collected during GCES I, GCES II and the long-term extension of the short-term GCES II studies. However, monitoring should not wait until all crucial resources are identi- fied and thoroughly understood or else some of these resources may be permanently degraded or lost from the Canyon.
THE GCES PROGRAM: PAST, PRESENT, AID FUTURE... 253 CONCLUSIONS The research program that has been ongoing in the Grand Canyon is probably inadequate to thoroughly understand all of the functions of the Canyon ecosystem. The program continues to develop and become more integrated and sophisticated. There is increasing recognition that a longer term research program is essential to develop the data that will allow an adequate understanding of resource responses identified by a monitoring program. It is also recognized that the monitoring program should be started during the present short-term studies and that it should be a complex, data rich program Hat will continue for years (a decade or more) after the completion of the EIS, in order to evaluate the consequences of the selected EIS alter- native for dam and Canyon management. The Grand Canyon ecosystem is an unique resource that we should make every effort to understand and protect. REFERENCES National Research Council. 1987. River and Dam Management: A Review of the Bureau of Reclamation's Glen Canyon Environmental Studies. Water Science and Technology Board. National Academy Press, Washington, D.C. U.S. Department of Interior. 1988a. Glen Canyon Environmental Studies Report. Bureau of Reclamation, Flagstaff, Ariz. U.S. Department of Interior. 1988b. Glen Canyon Environmental Studies, Executive Summa- ries of Technical Reports. Bureau of Reclamation, Flagstaff, Ariz. U.S. Department of Interior. 1988c. Glen Canyon Environmental Studies, Executive Review Committee final report. Bureau of Reclamation, Salt Lake City, Utah.
