8119

• UCREFRP Catalog Number: 8119
• Author: Valdez, R. A. and B. R. Cowdell.
• Title: Effects of Flow Regulation and Ice Formation on Overwinter Nursery Habitat and Survival of Age-0 Colorado Squawfish in the Green River Below Flaming Gorge Dam - Draft.
• USFW Year: 1996.
• USFW - Doc Type: Logan, Utah.
• Copyright Material: NO

I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I

TABLE OF CONTENTS

ACKNOWLEDGMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. II

EXECUTIVE SUMMARY ............................................... vi
1.0 INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 1
1.1 Purpose And Objectives ....... . . . . . . . . . . . . . . . . . . . . . . . . . .. 1
1.2 Background . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . " 1
2.0 STUDY AREA ............................................... 2
3.0 METHODOLOGY. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 4
3.1 River Hydrology and Chemistry . . . . . . . . . . . . . . . . . '. . . . . . . . . .. 4
3.2 Backwater Mapping ..................................... 5
3.3 Winter Habitat Measurements ............................. 5
3.4 Physical and Chemical Habitat Criteria ............ . . . . . . . . .. 6
4.0 RIVER HYDROLOGY ......................................... 7
4.1 Flows During Winter of 1993-94 . . . . . . . . . . . . . . . . . . . . . . . . . . .. 7
4.2 Flows During Winter of 1994-95 . . . . . . . . . . . . . . . . . . . . . . . . . " 10
5.0 RIVER ICE CONDITIONS ..................................... 11
5.1 Winter of 1993-94 ..................................... 13
5.1.1 Air and Water Temperature. . . . . . . . . . . . . . . . . . . . . . " 13
5.1.2 Ice Formation .................................. 13
5.2 Winter of 1994-95 ..................................... 16
5.2.1 Air and Water Temperature . . . . . . . . . . . . . . . . . . . . . . " 16
5.2.2 Ice Formation .................................. 16

6.0 RESULTS................................................. 17

7.0 DISCUSSION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 20
7.1 Ice Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 22
7.2 Other Considerations ................................... 23
RECOMMENDATIONS .......................................... 28
LITERATURE CITED. . .............. ........... . .. . ... . ......... 29

APPENDIX A: DATA SHEETS AND CODES USED FOR THE WINTER ICE STUDY

APPENDIX B: DESCRIPTIONS, MAPS, AND PHOTOGRAPHS OF BACKWATERS

iii