FLOOD07952

• County: Fremont
• Community: Canon City
• Stream Name: Four-mile Creek, Mud Gulch
• Basin: Arkansas
• Title: Floodplain Management Study - Four-Mile Creek and Mud Gulch at Canon City
• Date: 10/1/2002
• Prepared For: Canon City, Fremont County
• Prepared By: USDA Soil Conservation Service
• Floodplain - Doc Type: Floodplain Report/Masterplan

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HYDROLOGIC AND HYDRAULIC ANALYSIS

Flood Characteristics

Floods in the study area are usually caused by general rainstorms and

cloudburst storms during the period of May through September. Floods resulting

from prolonged, heavy rainfall over the watershed are characterized by moderate

peak flow of moderate volume and duration. The cloudburst type is a high-intensity,

short-duration rainstorm that produces a flood of high-peak flow, short duration and

small \'olume of runoff.

Flood potential also exists from rapid melting of heavy snow cover in late

spring and summer. Floodflows resulting from snow melt are characterized by

moderate peaks, large volumes, and long duration. Arkansas River peak flow from

snow melt occurs in June and July. This peak flow, in combination with rainfall, can

cause severe flooding.

Hydrologic Analysis

No independent hydrologic analysis was performed for this study. The

hydrologic findings presented in the N.R.C.S. Flood Plain Study \vere used for this

flood plain examination. Those findings are as follows:

The Four-Mile Creek flows southerly out of the Pike National Forest,
whereas the Mud Gulch flows southerly out of a small local drainage.
They both join the Arkansas River at Canon City. The NRCS TR-2o
(Computer Program for Project Formulation Hydrology) was used in
frequency flow calculations for Mud Gulch. Four-Mile Creek's
discharges were computed by regional analysis.

Snow Melt Analvsis -- The effect of snow melt on runoffs was investigated.

The U.S. Army Corps of Engineers computer program, HEC-I, was used to test the

.

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