FLOOD10348

• County: Statewide
• Stream Name: Colorado River
• Title: Floodplain Information Report, Volume 4, Colorado River from Rifle to Utah Stateline
• Date: 5/1/1995
• Prepared For: Recovery Implementation Program for Endangered Fish Species in the Upper Colo
• Prepared By: CWCB
• Floodplain - Doc Type: Floodplain Report/Masterplan

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

TABLE OF CONTENTS

Preface
1.0 INTRODUCTION.......................... '. . . . . . . . . . .. 1

1.1 Purpose........................................ 1

1.2 Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 1
1. 3 Related Flood Studies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 1

2.0 STUDY AREA ............................. '. . . . . . . . . . ." 3

2.1 I..ocation. ". : . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 3

2.2 Study Reach . . . . . . . . . . . . . . . . . . . . . . . ". . . . . . . . . . . . . .. 3

2.3 Basin Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 5
2.4 Summary of Drainage Areas. . . . . . . . . . . . . . . . . . . . . . . . . . .. 5
2.5 Flood Characteristics ................................ 7

3.0 HYDROLOGIC ANALYSIS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 10
3.1 Existing Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . : " 10
3.2 Generating New Information . . . . . . . . . . . . . . . . . . . . . . . . . . .. 10
3.3 Equation Selection Process . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 11
3'.4 Hydrologic Findings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 11

4.0 HYDRAULIC ANALYSIS ................................. 14
4.1 Base Mapping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 14
4.2 Stream Reaches . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 14
4.3 Field Surveys and Cross-Section Preparation ...... . . . . . . . . . . .. 17
4.4 Computing Flood Depths . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 18
4.5 Delineating Flood Boundaries ........................... 19

5.0 INTERPRETATION OF THIS REPORT. . . . . . . . . . . . . . . . . . . . . . . .. 22
5.1 Hydrologic Findings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 22
5.2 Hydraulic Findings. . . . . . . . . . . . . . . . . . . . . . . . . .' . . . . . . .. 22
5.3 Floodplain Delineations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 22

6.0 REFERENCES........................................ 23

liST OF TABLES

TABLE
1 Stream Gage Data
2 Drainage Area Summary
3 Flow Summary
4 Reach Classifications
5 Cross-Section Summary
6 Depth of Flooding Summary

PAGE
3
7
12
15
18
20

ii