River Resource Management in the GRAND CANYON -- Copyright -- Preface -- Contents -- Executive Summary -- WORK OF THE NRC COMMITTEE -- OBJECTIVES AND DESIGN OF THE GCES -- RESULTS OF THE GCES -- Operations of Glen Canyon Dam -- Sediment and Hydrology -- Biological Resources -- Recreation -- Hydropower Economics -- Cultural Resources -- Institutional Influences on the GCES -- Nonuse Values -- ACHIEVEMENTS OF GCES -- LIST OF NRC REPORTS -- 1 Introduction and Background -- ROLE OF THE NRC -- REFERENCES -- 2 Scope and Organization of the Glen Canyon Environmental Studies -- INTRODUCTION -- SCOPE AS DEFINED BY MANAGEMENT OPTIONS, RESOURCES, AND THE ECOSYSTEM CONCEPT -- Management Options -- Resources -- The Ecosystem Perspective -- OTHER INFLUENCES ON THE SCOPE OF GCES -- Administrative Policy -- Law and Politics -- ORGANIZATION OF THE STUDY GROUP -- CONCLUSIONS -- REFERENCES -- 3 Historical Context for Long-Term Management of Glen Canyon Dam -- HISTORY OF GRAND CANYON NATIONAL PARK -- Introduction -- Predesignation History -- Designation as a Park -- Role of the Colorado River in the Park: Conduit Between Upper and Lower Basins -- FUTURE BASIS FOR MANAGEMENT OF GRAND CANYON RESOURCES -- Intergenerational Equity -- Simulated Naturalness -- REFERENCES -- 4 Operation of Glen Canyon Dam -- INTRODUCTION -- HYDROLOGY THROUGH THE GRAND CANYON -- Hydrology Prior to Construction of Glen Canyon Dam -- Hydrology Following Closure of the Dam -- Tributary Inflows Below the Dam -- Hydrological Regimes During the GCES Research Periods -- Travel Time Through Grand Canyon -- OPERATING RULES FOR GLEN CANYON DAM -- Seasonal and Annual Operations -- Formal Description of Operating Rules -- Monthly and Annual Releases -- Daily and Hourly Operations -- Daily Operations -- Experience with Interim Flows and Exception Criteria -- EIS Preferred Alternative.

Beach/Habitat-Building Flows -- Operational Constraints on Experimental Floods -- WATER SUPPLY ABOVE THE DAM -- Water Balance In Lake Powell -- Upper-Basin Depletions -- Evaporation Loss -- Storage in Lake Powell -- Flood Control -- Current Rules Related to Floods -- Flood Control Changes Recommended in EIS -- Reregulating Dam -- Summary -- RECOMMENDATIONS -- REFERENCES -- 5 Sediment and Geomorphology -- WHY SEDIMENT AND GEOMORPHOLOGY ARE IMPORTANT -- Amount of Sediment Is Not a Problem in the Grand Canyon -- Management of Sediment -- Rapids -- Sand as Substrate -- SEDIMENT STUDIES OF GCES PHASE I -- Bureau of Reclamation Model -- Early Assumptions Concerning Sediment Movement -- Coordination and Communication -- Leadership for GCES -- NRC Committee Recommendations After GCES I -- WHAT IS NEEDED CONCERNING SEDIMENT AND GEOMORPHOLOGY -- Sediment Budget -- Sediment Budget by Reach -- Sand Distribution Between Main Channel and Beaches -- Flood Waves -- U.S. Geological Survey Effort on Sediment Modeling -- USGS Effort on Eddy Modeling -- Linking of Sediment Modeling and Eddy Modeling -- NAU Beach and Bar Studies -- WHERE WE STAND NOW -- RECOMMENDATIONS -- REFERENCES -- 6 Organisms and Biological Processes -- INTRODUCTION -- LAKE POWELL -- Characteristics of Lake Powell -- Influence of Dam Operations on the Lake -- Overview of Lake Studies -- Changes in the River Caused by the Dam -- THE COLORADO RIVER BETWEEN GLEN CANYON DAM AND THE PARIA RIVER -- Primary Producers and Their Metabolism -- THE COLORADO RIVER FROM THE PARIA RIVER TO LAKE MEAD -- Physical Characteristics -- Overview of Communities -- Aquatic Habitats -- Humpback Chub -- Other Fishes -- Tributaries -- Biotic Interactions -- Overview of Biotic Studies on the Main Stem -- THE RIPARIAN ZONE -- OUTCOMES OF BIOLOGICAL STUDIES -- REFERENCES -- 7 Recreation and Nonuse Values.

THE ROLE OF ECONOMIC VALUES IN GCES AND THE EIS -- Use and Nonuse Values Defined -- Measurement of Nonuse Values -- OVERVIEW OF RECREATIONAL USES -- Fishing in Glen Canyon -- Fishing in Grand Canyon -- Day Rafting -- White-Water Boating -- Recreation at Lakes Powell and Mead -- Recreation and Native American Tribes -- ECONOMIC EFFECTS OF DAM OPERATION ON RECREATION -- Background on Economic Methods Used -- Economic Effects of Dam Operations on Anglers -- Economic Effects of Dam Operations on Day Rafting -- Economic Effects of Dam Operations on White-Water Boating -- Economic Impacts of Dam Operations on Native American Tribes -- SUMMARY OF EFFECTS OF DAM OPERATIONS ON RECREATION -- STUDIES OF NONUSE VALUE -- SUMMARY -- REFERENCES -- 8 Cultural Resources -- NATIVE AMERICANS IN THE GRAND CANYON REGION -- Overview of Present Residents -- Historical Perspective -- Background Information on the Six Tribes -- Hualapai -- Havasupais -- Southern Paiute Consortium -- Hopis -- Navajos -- Zunis -- ARCHAEOLOGICAL STUDIES -- ETHNOGRAPHIC STUDIES -- Perspectives on Ethnography -- Sacred Sites -- The Hualapai Tribe -- Southern Paiute -- Hopi -- Navajo -- Zuni -- Perspective on Tribal Studies -- SUMMARY -- RECOMMENDATIONS -- REFERENCES -- 9 Power Economics -- INTRODUCTION -- FLOWS AFFECT ELECTRICAL OUTPUT AND COSTS -- THE INSTITUTIONAL CONTEXT -- COST ESTIMATES FOR ALTERED FLOW REGIMES -- RECOMMENDATIONS -- REFERENCES -- 10 Institutional Influences on the Glen Canyon Environmental Studies -- INSTITUTIONAL STRUCTURE OF GCES -- INTERAGENCY CONFLICT IN THE EVOLUTION OF GCES -- GOAL SUBSTITUTION BY AGENCIES WORKING FOR GCES -- EXTERNAL REVIEW - GCES AND THE NRC -- THE ROLE OF FUNDING IN GCES -- TIME CONSTRAINTS IN GCES RESEARCH -- FUTURE INSTITUTIONS -- RECOMMENDATIONS -- REFERENCES -- 11 Lessons of the Glen Canyon Environmental Studies -- INTRODUCTION.

ELEMENTS OF A USEFUL ECOSYSTEM ANALYSIS -- The Planning Sequence -- Review of Existing Information -- Definition of Scope -- Using What Is Already Known -- Implementation of the Plan -- Formation of the Study Group -- Contracting and Project Leadership -- Outside Advice -- Achievements and Dissemination of Information -- Reference to Final Objectives -- Budgetary Continuity -- COMPLETION AND ANTICIPATION OF FUTURE NEEDS -- Synthesis -- Archiving for the Future -- Continuity into the Future -- ACHIEVEMENTS OF GCES -- Important Discoveries of GCES -- Recognition of the Need for Comprehensive Environmental Studies -- Adaptive Management and Long-Term Monitoring -- External Expertise and Review -- A HOPEFUL VIEW OF THE FUTURE -- REFERENCES -- Appendix A Biographical Sketches of Committee Members -- NATIONAL RESEARCH COUNCIL STAFF.