WSP11877

• File Number: 8220.101.10
• Description: Colorado River-Water Projects-Glen Canyon Dam/Lake Powel-Glen Canyon Adaptive Management
• Basin: Colorado Mainstem
• Water Division: 5
• Date: 9/1/2002
• Author: DOI-BOR-NPS-USGS
• Title: Proposed Experimental Releases from Glen Canyon Dam and Removal of Non-Native Fish-Environmental Assessment
• Water Supply Pro - Doc Type: Report/Study

Page

01184

Contents

Cover Sheet

Executive Summary ............................................................................................. vi
Introduction ......................................................................................................... viii

Chapter 1 Purpose of and Need for Action
1.1 Purpose and Need .................................................................................... 1
1.2 Related Documents, Programs, and Actions ......................................... 1
1.2.1 Final Environmental Impact Statement and Record of Decision 1
1.2.2 Glen Canyon Dam Adaptive Management Program .................. 2
1.2.3 Colorado River Management Plan ................................................. 4
1.2.4 The Lake Mead Management Plan................................................. 4
1.2.5 The Colorado River Recreation Management Plan...................... 4
1.2.6 Personal Watercraft Rule-Making Glen Canyon National
Recreation Area, Arizona and Utah ................................................... 4
1.2.7 Tamarisk Removal............................................................................ 5
1.2.8 Brown Trout Removal...................................................................... 5
1.2.9 Interim Surplus Guidelines ............................................................. 5
1.3 Decisions Needed and Permits Required............................................... 6
1.4 Public Involvement ................................................................................... 7
1.4.1 Federal Advisory Committees within the GCDAMP.................. 7
1.4.2 Tribal Consultations ......................................................................... 8
1.4.3 Park Concessionaires........................................................................ 8
1.4.4 Public Meetings ................................................................................. 8

Chapter 2 Description of Alternatives .............................................................. 9
2.1 No Action Alternative ............................................................................... 9

2.2 Proposed Action .......................... .......... ...... ............. ........ .......................... 13
2.2.1 Proposed Dam Operations .............................................................. 13
2.2.2 Mechanical Removal of Non-native Fish ...................................... 23
2.3 Potential Means to Alleviate Adverse Effects or Reduce

Incidental Take .... ............. ................... ..... ...... .............. ...... ...... .... ............... 24
2.4 Alternatives Considered but Eliminated From Detailed Analysis..... 25

Chapter 3 Affected Environment and Environmental Consequences
3.1 Colorado River Ecosystem Linkages....................................................... 27

3.2 Water ........................................................................................................... 38
3.2.1 Affected Environment .................................................................... 38
3.2.2 Environmental Consequences....................................................... 38

3.3 Sediment. ..... ... .......................... ........ ....... ... ..... ....... ..... ......... ....... ....... ......... 40
3.3.1 Affected Environment .................................................................... 40