WSP12565

• File Number: 8240.200.30.A
• Description: Colorado River Basin Threatened-Endangered - UCRBRIP - RIPRAP - Flow Recommendations
• State: CO
• Basin: Colorado Mainstem
• Water Division: 5
• Date: 7/1/2003
• Author: US FWS
• Title: Flow Recommendations to Benefit Endangered Fishes in the Colorado and Gunnison Rivers - 07-01-03
• Water Supply Pro - Doc Type: Report/Study

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TABLE OF CONTENTS

Page

LIST OF TABl..ES .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iv

UST OF FIGURES ......................................................... ix

NOTATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. xv

ACKNOWLEDGMENTS .................................................. xvii

EXECUTIVE SUMMARY ................................................ xviii

1.0 INTRODUCTION................................................... 1-1

1.1 Background.................................................... 1-1

1.2 Overview of Aspinall Unit Investigations . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 1-5

1.2.1 Study Area ................................................ 1-6

1.2.2 Study Objectives and Approach . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 1-6
1.2.3 Aspinall Unit Operations During the Study Period ................. 1-9
1.2.4 Development of Integrated Flow Recommendations . . . . . . . . . . . . . . .. 1-9

2.0 HYDROLOGY AND GEOMORPHOLOGY OF THE COLORADO AND

GUNNISON RIVERS ................................................ 2-1

2.1 Hydrology..................................................... 2-1

2.1.1 Overview ................................................. 2-1

2.1.2 Water Development ......................................... 2-2
2.1.3 Historical Operation of the Aspinall Unit ....................... 2-14
2.1.4 Aspinall Unit Operation During the Study Period . . . . . . . . . . . . . . . .. 2-16
2.2 Geomorphology................................................ 2-23
2.2.1 Longitudinal Variation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 2-23
2.2.2 Influence of Water Development on Se~ment Transport
and Channel Maintenance ................................... 2-29
2.2.3 Relationship of Fine Sedi~ent to Periphyton and
Invertebrate Biomass ....................................... 2-38
2.2.4 Influence of Water Development on Floodplain Inundation ......... 2-45
2.2.5 Influence of Water Development on River Temperature . . . . . . . . . . .. 2-49

3.0 FISHES OF THE COLORADO AND GUNNISON RIVERS ................. 3-1
3.1 Fish Community ................................................ 3-1
3.1.1 Native Species ............................................. 3-1
3.1.2 Nonnative Species .......................................... 3-2
3.1.3 Influence of River Flow on Non-Endangered Fishes in the
Colorado and Gunnison Rivers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 3-8

Final Report

1

July 2003

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