FLOOD10401

• County: El Paso
• Community: Colorado Springs
• Stream Name: Fountain Creek
• Basin: Arkansas
• Title: Fountain Creek Drainage Basin Planning Study - Volume 1
• Date: 7/1/1994
• Prepared For: Colorado Springs
• Prepared By: Muller Engineering Company, Inc.
• Floodplain - Doc Type: Floodplain Report/Masterplan

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damage along the east side of the city and in the Security and Fountain
areas.

· July 24, 1965:

Flash flooding in the Seven Falls area causes extensive damage in the
Cheyenne Mountain region.

· July 24, 1970:

Flash floods in northeastern Colorado Springs causes heavy damage to
roads and homes.

· August 20, 1970:

9 to 11 inches of rain caused flooding in Rock Creek Canyon prompting
rock slides and extensive property damage.

· July 2, 1980:

Heavy rain causes extensive flooding throughout Colorado Springs.

· July 19, 1985:

Thunderstorms "dumped" up to 5-1/2 inches of rain in the Broadmoor area
in three hours causing flash floods throughout the southwest sections
of the city.

4.5 HYDROLOGIC APPROACH

Extensive hydrologic information exists or was generated as a part of this
evaluation and its companion hydrologic analysis for Monument Creek (CH2M Hill,
unpublished). Since the companion analysis occurred partly in advance of this
evaluation and established much of the background assumptions, these will simply
be referenced herein rather than described in detail. The magnitude of the 10-
year and 100-year floods for Fountain Creek were estimated using several
different procedures. The comparison and composite of results from the existing
information, and statistical, design storm and regional hydrologic analyses were
utilized to produce recommended design flows in a following section of this
report.

4.6 STREAMFLOW STATISTICAL ANALYSIS

The first of these hydrologic procedures is one which utilizes the statistics of
annual peak flow records from the stream gaging stations. A Log-Pearson Type III
frequency analysis, in accordance with the United States Water Resource Council
Bulletin #178 (HECWRC 1982), was performed on the three previously described gage
stations (Tejon, Janitell, and Security gages). Table 4.6-1 contains the Log-
Pearson Type III 100-year discharges developed for the Manitou Gage. The use of
past historical floods, their magnitude, and how they are incorporated into the
hydrology model analysis can greatly affect the estimated peak flow. In the
initial Log-Pearson Type III analysi's on the flows from the Manitou Gage,

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