8117

• UCREFRP Catalog Number: 8117
• Author: Modde, T. and G. Smith.
• Title: Flow Recommendations for Endangered Fishes in the Yampa River.
• USFW Year: 1995.
• USFW - Doc Type: Denver, CO.
• Copyright Material: NO

TABLE OF CONTENTS
TABLE OF CONTENTS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

LIST OF TABLES ............................................... ii

LIST OF FIGURES .............................................. jii
EXECUTIVE SUMMARY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . " iv
BACKGROUND ................................................. 1

Purpose ....".............................................. 1

Study Area .......... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Biological Background .. . . . . . " . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
OBJECTIVE AND APPROACH ...................................... 5
BIOLOGICAL AND HYDROLOGICAL DATABASE.......... . ..............6
Endangered Fish Distribution, Abundance and Habitat Use ............. 6
Colorado squawfish ...... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Humpback chub ....................................... 8
Razorback sucker ...................................... 8

Bonytail . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Spawning Requirements of Endangered Fishes . . . . . . . . . . . . . . . . . . . . . . 9
Colorado squawfish ...................... . . . . . . . i . . . . . . . 9
Humpback chub ...................................... 11
Razorback sucker ..................................... 14
Association of Nonnative Fishes with Native Fishes . . . . . . . . . . . . . . . . . . 14
Comparison of Historical and Virgin Hydrographs . . . . . . . . . . . . . . . . . . . . 19
Habitat Maintenance and Geomorphology . . . . . . . . . . . . . . . . . . . . . . . . . 21

DISCUSSION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

RECOMMENDATIONS ........................................... 27
Flow Recommendations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Spring (March 21 - June 21) . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . 30
Colorado squawfish ............................... 30
Razorback sucker ................................ 31
Humpback chub. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Spring recommendations ........................... 31
Summer (August 1 - September 30) ........................ 31
Colorado squawfish ............................... 3'1
Humpback chub . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
Summer recommendations . . . . . . . . . . . . . . . . . . . . . . . . . . 32
Fall and Winter (October 1 - March 31) . . . . . . . . . . . . . . . . . . . . . . 32
Colorado squawfish ............................... 32
Humpback chub . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
Fall and Winter recommendations . . . . . . . . . . . . . . . . . . . .. 32
Summary of flow recommendations . . . . . . . . . . . . . . . . . . . . . . . . . 33
Baseflow months August - March ..................... 33
High flow months . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Recommended Actions ........................................... 33
LITERATURE CITED. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . .35

APPENDIX 1 .................................................. 41

APPENDIX 2 .................................................. 42

APPENDIX 3 .................................................. 44

APPENDIX 4 ....................................................

APPENDIX 5 ....................................................