FLOOD09565

• County: Statewide
• Community: State of Colorado
• Basin: Statewide
• Title: Flood Hazard Mitigation Plan for Colorado
• Date: 1/1/1983
• Prepared For: State of Colorado
• Prepared By: CWCB
• Floodplain - Doc Type: Flood Mitigation/Flood Warning/Watershed Restoration

TABLE OF CONTENTS

.

Letter of Transmittal
Preface............ .
Acknowledgements
Table of Contents
List of Figures
Executive Summary

.

. .

Page
.. . . i
. ii
. v
vii
.. . . .. . . . ix

. . . . . .

. . . . . . .

j,

1.0

INTRODUCTION

. ........ ................. ..............

1.1 Purposes .. 1
1.2 Scope . .. . . . .. . . . . .. 2
1.3 Authority .. . 2
1.4 Definitions .. . . . . . . .. 3
1.5 Conceptual Emphasis .. . . . . 5

2.0

BACKGROUND

...... .......... ................ ...........

7

2.1

Lawn Lake Dam Failure

............ .... ...........

7

2.1.1 Setting ..... .. .. . . ... 7
2.1.2 The Flood .. ... . . . . 9
2.1.3 People at Risk .. . .. 11
2.1.4 The warning . . . .. . . . 13
2.1.5 Loss of Life and Flood Damages 16
2.1.6 Agency Response ... . .. . . . . 18
2.1. 7 Mitigation Measures . . . 25
2.2 Identification of the Hazards ... ...... ......... 28

2.2.1 People and Floods .., . 28
2.2.2 Historic Flood Damages 31
2.2.3 Causes of Floods .. 35
2.2.4 General Rain Floods . 37
2.2.5 Thunderstorm Floods . 37
2.2.6 Snowmelt Floods . . . . .. . . 37
2.2.7 Rain on Snow Floods . 38
2.2.8 Dam Failure Floods . . .. 38

2.3 Legal Framework ..... ................... ..... 41
..
2.3.1 Dam Safety ..... ... ...... . 41
. 2.3.2 Floodplain Management 42
2.3.3 Emergency Preparedness . .. . 45
2.4 Governmental Organizations . ..... . . . . . . . . . . . . . . . 46

2.4.1 City and Town Government .. . . 46
2.4.2 County Government ...... . . . . . 46
2.4.3 Regional Planning Agencies . . .. 46
2.4.4 State Government ........ .. . 47
v