WSPC12525 ‎(2)‎

• File Number: 8220.101.10
• Description: Colorado River Water Projects - Glen Canyon Dam-Lake Powell - Adaptive Management
• State: CO
• Basin: Colorado Mainstem
• Date: 6/2/1998
• Author: DOI-GCMRC
• Title: Assessment of Impacts of Glen Canyon Dam Operations on Water Quality Resources in Lake Powell and the Colorado River in Grand Canyon - Grand Canyon Monitoring and Research Center - Draft - 06-02-98
• Water Supply Pro - Doc Type: Report/Study

0U2374

1. Introduction to Limnology ................................................ 16

2. Seasonal Patterns seen at Lake Powell ...................................... 19

3. Historic Patterns seen at Lake Powell . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 23

B. GLEN CANYON DAM RELEASES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ., 27

1. Historical trends. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 27

2. Seasonal Patterns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 29

V. DISCUSSION ............................................................. 30

A. VALUE OF EXISTING AND PAST MONITORING PROGRAMS . . . . . . . . . . . . . . . . . . . . . . . .. 30

B. ASSESSMENT OF FACTORS AFFECTING WATER QUALITY CONDITIONS ............... 31

1. Meteorological Conditions. . . . . . ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 32

2. Inflow Hydrology ...... _ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 32

3. Glen Canyon Darn Operations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 34

VI. CONCLUSIONS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 45

A. INFLUENCE OF DAM OPERATIONS ON LAKE WATER QUALITY ....................... 45

1. Release volumes ........ . . . . . . . . . . . . . . . . . . . . . . . . . . . . _ _ . . . . . . . . . . . . . . . . .. 46

2. Timing of Reservoir Releases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 46

3. Operation of non-power release structures ................................... 46

4. Changes in Variability of Downstream Releases ............................... 47

B. INTEGRATION WITH DOWNSTREAM SYSTEMS .................................. 48

1. Grand Canyon Aquatic Ecosystem. . . . _ . . . . . . . . . _ . . . . . . . . . . . . . . . . . . . . . . . . . .. 48

2. Lake Mead. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 49

LITERATURE CITED. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 49

APPENDICES. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 54

ASSESSMENT PROSPECTUS . . . . . . . . . . . . . . . . . . . _ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 54
06/02/98 DRAFT poc ,; of62