WSP09657

• File Number: 8220.101.09B
• Description: Glen Canyon Dam/Lake Powell
• State: AZ
• Basin: Colorado Mainstem
• Date: 1/1/1993
• Author: BOR
• Title: Operation of Glen Canyon Dam Draft Environmental Impact Statement
• Water Supply Pro - Doc Type: EIS

Contents

General location map

Page
Frontispiece

Chapter I Purpose of and need for action
Background ' , . . , , , ,
Cooperating agencies
Management responsibilities
Document organization
Location and setting
Grand Canyon National Park
Historical perspective ' ,
Predam flows , , , . '
Postdam flows (historic operations)
Glen Canyon Dam operations
Authorities and institutional constraints
Grand Canyon Protection Act of ]992 (Public Law 102-575)
Law of the River ,
National parks
Environmental
Cultural preservation
Native American, ,
Glen Canyon Environmental Studies
Phase I (] 982-88) , , . . , ,
Phase II (]988-present), , . ,
Relationship between Glen Canyon Dam EIS and Electric Power Marketing ElS
Scopingsummary , , . , , , . , . ,
Public issues and concerns , , . '
Significant issues identified for detailed analysis

]
2
3
4
5
5
5
6
6
6
6
7
8
8
8
9
9
9
9
10
10
11
11
11
12

Chapter II Description of alternatives
Process used to formulate alternatives
Alternatives considered in detail
Unrestricted fluctuating flows
No Action Alternative . ,
Maximum Powerplant Capacity Alternative
Restricted fluctuating flows , '
High Fluctuating Flow Alternative
Moderate Fluctuating Flow Alternative
Modified Low Fluctuating Flow Alternative (Preferred Alternative)
Interim Low Fluctuating Flow Alternative ,
Steady flows . . . , , , ,
Existing Monthly Volume Steady Flow Alternative
Seasonally Adjusted Steady Flow Alternative
Year-Round Steady Flow Alternative
Common elements . , , , , . '
Adaptive management
Monitoring and protecting cultural resources
Flood frequency reduction measures
Beach/habitat-building flows

]5
]5
]6
]6
]6
24
24
26
27
27
30
30
32
33
33
34
34
35
36
36

iii