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

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CWCB Hvdroloqy Worksheet

Page 3

Title of Study:
County:
Calculations By:

FIS - Gunnison County, Colorado and Incorporated Areas
Gunnison
jrs Date: January 14, 2002

Documentation
This workbook estimates 1 OO-year discharges for approximate floodplains in Colorado using the following
source:
Browning, T.W. 1999, Guidelines for Determining 100-year Flood Flows for Approximate
Floodplains in Colorado, Version 4.0. Colorado Water Conservation Board. January.

River Basin

I COl-3: Colorado, lower Gunnison River Subregion
Status of Regression Equations for this sub-region:

B

Draft

Regression Equation Data
Q=aAb

Where:
Q = Discharge (cis)
A = Drainage Area (square miles)
a = coefficient =
b = coefficient =

180,8
0.578

Limited by:
Minimum Drainage Area =
Maximum Drainage Area =

2 square miles
8000 square miles

Discharge Calculations

Drainage Drainage l00-year
PointlD Drainage Area Description Area (mi") Discharge (cfs)
460 East Fork Little Blue Creek - uls of T 47 N R 4 W, Sect 18 0.74 Outside Bounds
461 Big Blue Creek - uls of T 47 N R 5 W, Section 23 58,39 1,897
470 Little Cimarron River - u1s of T 47 N R 5 W, Section 32 21.71 1,071
471 Little Cimarron River - uls of Gunnison County Line 55.64 1,645
480 Cimarron River. uls of Gunnison County Line 85.60 2,367

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CWCB_Hydrology.xls