FLOOD00880

• County: Mesa
• Community: Rifle
• Stream Name: Colorado River
• Title: Floodplain Information Report - Colorado River Mainstem From Rifle to Utah-Colorado State line
• Date: 4/1/1996
• Prepared By: CWCB
• Floodplain - Doc Type: Floodplain Report/Masterplan

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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 Location........................................ 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

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