FLOOD02581

• Designation Number: 557
• County: Gunnison
• Community: Unincorporated Gunnison County
• Basin: Gunnison
• Title: Hydrology Addendum
• Date: 2/1/2002
• Prepared For: Gunnison County and CWCB
• Prepared By: Montgomery Watson Harza
• Floodplain - Doc Type: Floodplain Report/Masterplan

.
.
.
.
.
.
.
.
.
I.
.
.
.
.
.
.
,.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
'.
.
.
.
.
.
.
I.
.
I.
.
.
.
.
.
'.
.

INTRODUCTION

Purnose and Scope
This Hydrology Addendum (HA) was prepared to provide supporting documentation for the
approximate lOO-year floodplain boundaries shown in the Gunnison County Unincorporated
Areas PIS, dated September 29, 1989. The FIRMs were prepared using both detailed and
approximate floodplain mapping techniques, Engineering information was not provided by
FEMA to support the approximate floodplain delineations shown on the FIRMs. This HA
provides limited engineering information to fulfill that need.

This HA includes:

1. Authorization for the report and its purpose and scope;

2, Study area description including information on the communities, the watershed, any known
flooding historylflooding problems, previous studies and projects, and community response
to the CWCB designation and approval process;

3, Description of hydrologic and hydraulic information; and

4. Floodplain management program,

Authorization
The CWCB has certain statutory responsibilities relating to the designation and approval of
floodwater runoff channels or basins as follows:

... "to devise and formulate methods, means, and plans for bringing about the greater
utilization of the waters of the state and the prevention of flood damages therefrom, and
to designate and approve storm or floodwater runoff channels or basins, and to make such
designations available to legislative bodies of cities and incorporated Counties, to County
planning commissions, and to boards of adjustment of cities, incorporated Counties, and
counties of this state"... Section 37-60-106(l)(c) of the Colorado Revised Statues (CRS),

A CWCB designation and approval of current floodplain information is needed for the
unincorporated and incorporated areas of Gunnison County, Colorado, The CWCB has prepared
this HA as a means of designating the Gunnison County FIRMs so that the communities can
better implement its floodplain management program.