FLOOD04076

• County: Larimer
• Community: Larimer County Unincorporated
• Basin: South Platte
• Title: Flood Insurance Study - Larimer County Unincorporated Areas, Volume 2 of 3
• Date: 3/23/1999
• Prepared For: Larimer County
• Prepared By: FEMA
• Floodplain - Doc Type: Historic FEMA Regulatory Floodplain Information

TABLE OF CONTENTS

Volume 1

Page

1. 0 INTRODUCTION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1

1.1 Purpose of Study................................................. 1
1.2 Authority and Acknowledgments. ........ ...... ...... .... ...........1
1.3 Coordination. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

2. 0 AREA STUDIED.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2

2.1 Scope of Study................................................... 2
2.2 Cornrnunity Description...... . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . .. ..4
2.3 Principal Flood Problems......................................... 6
2.4 Flood Protection Measures........... . . . . . . . . . . . . . . . . . . . . . . . . . . . .10

3.0 ENGINEERING METHODS.. . . . . . . . . . .. . . .. .. . . . . . . . .. . . . . . . . .. . . . . . . . . . . . .. .11

3.1 Hydrologic Analyses.............. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12
3.2 Hydraulic Analyses. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13

4.0 FLOOD PLAIN MANAGEMENT APPLICATIONS. ...... ...... ...... ...... ..........21

4.1 Flood Boundaries.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . _ . . . . . . . . . . . . . . . . .21
4.2 Floodways. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22

5.0 INSURANCE APPLICATION....... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .67

5.1 Reach Determinations. . . . . . . . . . . . . . ~ . . . . . . . . . . . . . . . . . . . . . . . . . . . . .67
5.2 Flood Hazard Factors.... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .67
5.3 Flood Insurance Zones........................................... 74
5.4 Flood Insurance Rate Map Description............ ................74

6.0 OTHER STUDIES......................................... . . . . . . . . . . . . . . . .75

7.0 LOCATION OF DATA........... . . . . . . . . . . . . . . . . . . . . . " . . . . . . . . . . . . . . . . . . . .76

8.0 BIBLIOGRAPHY AND REFERENCES... ........... .... ......... ... ... """ ....76

9.0 REVISION DESCRIPTIONS. . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ., . . . . .80

9.1 First Revls1on.................................................. 80
9.2 Second Revision. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86
9.3 Third Revis1.on. .... ... . .... .. ... . . .. ..... ........ . . ...............96
9.4 Fourth Rev~sion...... . ..... . ... .. . ..... .. . ... .. . ... ... ...... '" . 96

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