WSP09202

• File Number: 8240.300.31.B
• Description: San Juan River - FWS Flow Recommendations
• Basin: San Juan/Dolores
• Water Division: 7
• Date: 2/1/1999
• Author: Biology Committee
• Title: Flow Recommendations for the San Juan River
• Water Supply Pro - Doc Type: Report/Study

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AUTHORS/ACKNOWLEDGMENTS .... , , . . . . . , . . . . , . . . , . . , . ' . . . . . . . . . inside front cover

SUGGESTED CITATION FORMAT...................,.....,.....,........., ,.. C - 1

PREFACE. . . , . . . . . . . . . , . . . . . . , . . , . . . , , . . . , , . . . . . , , . , . . . . . , . . . , . . . . . , . , . , .. P-1

EXECUTIVE SUMMARY. . . . . . . . . . . . . , . . . . . . , , . . . , . . . , . . , . . . . . . . . . . . . . . . . . . . . . S - 1

INTRODUCTION. . , . . . . . . . . . , . . . . . . . . , . . . . . . , . . . . . . . . . , . . . . . . , . , . , . . . . S - 1
RESULTS OF THE 7-YEAR RESEARCH PERIOD. . . . . . . . , . . . . . . . . . . . . . . . , . . . S - 2
FLOW RECOMMENDATION .......,.."".,...,..,.............,......, S - 3

CHAPTER 1: INTRODUCTION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . , . . . . . . . . . . . . . . . . . . . 1 - 1
DOCUMENT PURPOSE . . , . . . . , . . . . . . , . . . . , . . . , . , . . . . . . . . . . . . , . , . . . . . . . 1 - 1
DOCUMENT ORGANIZATION . , . . . . . . . . , . . . . . . , . . . . . . . . . , . . . . , . , . . . . . . .. 1 - 6

CHAPTER 2: GEOMORPHOLOGY, HYDROLOGY, AND HABITAT ......."........... 2 - 1
GEOMORPHOLOGY .......',...,....,................................ 2 - 1
General Description . . . . . . . . . . . . . . . . , . . . . . . . . , . . . . . . . . . . . . . . , . . . . . 2 - 1
Comparison with Green and Upper Colorado Rivers . . . . . . . . . , . . . . . . . . . . . 2 - 4
SJRIP Study Area .....,...............,.........,...........'... 2 - 6

HYDROLOGY. . . . . . . . . . . . . . . . . . . . . . . . . . . . . , . . . , . , . . . . . . . . , . . . . . . . . . . 2 - 12
Pre-Navajo Dam (1929 to 1961) ..,....,......,.........,.......... 2 - 12
Post-Dam Period (1962 to 1991) ......... . ' . . . . . ' . . . . . , . . . . . . . . . ' . , 2 - 15
Research Period (1992 to 1997) .........,.........'............... 2 - 15
WATER TEMPERATURE. . . . . . . . . . .. , , . . . . .. . . , . . , , . . , . . . . . , . . . . . . . . . . 2 - 17

HABITAT. . . . . . . . . . . . . . . . . , . . . . , . . , . . . . . . . . , . . . . . . . . . . . . , . . . . . . . . ' . . 2 - 17
Habitat Quantity . . . . . . . . . . . . . . . . . . . . . . ' . . . . . . . . . . . . . . . . . . . . , . . . . 2 - 21
Habitat Quality . . . . . . . . . . . . . . . . . . . . . . . . . , . , , , . . . . . . . . . . . . . . . , . . . 2 - 26
Comparison with Green and Colorado Rivers .............,........... 2 - 29

CHAPTER 3: LIFE HISTORY OF THE FISHES ...............,............,......, 3 - 1
COLORADO PIKEMINNOW .. ,. . . . . . . . . . . . . . . . . . . . . . . . , . . . . . . . . . . . . . . . . . 3 - 1

Spawning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 - 2
Eggs ....,.............................,'...................., 3 - 7
Larvae .............,.......' , . . . . . . . . . . . . , . . , . . , . . . . , . , . . . . . . . 3 - 8
Juveniles ...........,................,................,........ 3 - 9
Adults. . . . . . . . . . . . . . . . . , . . . , . . . . . , . , . . . . , . . . . . , . . . . . . . . . . , . . . . 3 - 11
RAZORBACK SUCKER .....,......."..'.......,.,................... 3 - 13

Spawning . . . . . . , . . . . , . . . . . . . ' . . . . . . . . . . , . . . , . , . . . . , . . . . . . . . . . . 3 - 13
Eggs .......',....,..."..,.....,.",.........,.".,....,.,., 3 - 15
Larval and Early Juvenile Life Stage ..........,...,..........,...... 3 - 16
Late Juvenile Life Stage, . . . . . . . , . . , , . . . . . . , . . , . . . . . . . . , . , . . . . . . . . 3 - 17
Adult Life Stage '....,..., , . . , . . . . . . . , , . . . . . . . . . . , . , , . , . , . , . . . . . 3 - 18

SJRIP Biology Committee
February 1999

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Table of Contents
Flow Report