FLOOD02650

• County: La Plata
• Stream Name: Animas River
• Basin: San Juan/Dolores
• Title: Hydrology Addendum to FIS La Plata County Unincorporated Areas
• Date: 5/21/2002
• Prepared For: La Plata County
• Prepared By: Montgomery Watson
• Floodplain - Doc Type: Floodplain Report/Masterplan

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CWCS Hvdroloav Worksheet

Pagel

Title of Study:
County:
Calculations By:

FIS -La Plata County, Colorado, Unincorporated Areas
La Plata
ggs Date: September 18, 2000

Documentation
This workbook estimates 100-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

[SAN-l: San Juan, Eastern San Juan 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 =

589.2
0.512

Limited by:
Minimum Drainage Area =
Maximum Drainage Area =

1 square miles
760 square miles

Discharge Calculations

Drainage Drainage 100-year
Area 10 Drainaae Area Description Area (mi') Discharae (cis)
SAN-1:1 Red Cr. @ Confl. wi Los Pinos R. 10.2 1,935
SAN-1:2 N. Fk. Texas Cr. @ Conll. wi S. Fk. Texas Cr. 3.5 1,119
SAN-1 :3 S. Fk. Texas Cr. @ Conll. wi N. Fk. Texas Cr. 5.5 1,410
SAN-1 :4 Texas Cr. @ Confl. wi Los Pinos R. 9.0 1,815
SAN.1:5 Bear Cr. @ ConII. wi Los Pinos R. 20.0 2,731
SAN-1:6 Wallace Gulch @ Conll. wi Los Pinos R. 7.0 1,596
SAN-1:7 Unnamed Trib. to Florida River @ confluence wi Forida R. 9.2 1,835
SAN-1 :8 Dry Cr. 2.7 mi d1s of CR 502 11.7 2,076
SAN-1:9 USGS Gaae No. 09363000 (Florida R. Nr. Duranao) 97.4 6,143
SAN-1:10 Florida R. @ d1s limit of aoprox. studY-leR 225Al 123.5 6,937

9(18/00
CWCB_lMlroloav IIa Illata co)