FLOOD04855

• County: Boulder
• Community: Boulder
• Stream Name: South Boulder Creek
• Basin: South Platte
• Title: Flood Hazard Area Delineation
• Date: 7/1/1986
• Prepared For: Boulder County
• Prepared By: UDFCD
• Contract/PO #: &&
• Floodplain - Doc Type: Floodplain Report/Masterplan

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- SUMMARY -

This report has identified the probable limits of flooding corresponding to the
occurrence of a 100-year flood event on South Boulder Creek between the Colorado
and Southern Railroad crossing and Eldorado Springs.

Floodplain limits are based on hydrologic information furnished by the Omaha
District-U.S. Army Corps of Engineers. Preliminary hydraulic information
developed by the COE was utilized by Greenhorne & O'Mara, Inc. to evaluate
hydraulic conditions along the study reach. Flood profiles and flood limits are
based on existing floodplain conditions as reflected by the mapping (1980 aerial
photography). Flood profiles also reflect partial blockage (25 percent)
conditions at bridge structures where the bridge structure would be inundated.
Unobstructed channel conditions were assumed at bridges where flDWS were confined
below the low bridge superstructure. Floods of greater magnitude than those
addressed in this report can and will occur in the future.

Although the South Boulder Creek basin is largely undeveloped, there is still
potential for significant flood damage to residences, commercial/industrial
buildings, and other structural features situated in the floodplain. Regulation
of future construction in the floodplain will help mitigate any increases in
flood damage potential.

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REFERENCES

1.

Reids Aerial Mapping: Topographic Mapping, Scale 1" = 100', 2-foot contour
interval; Urban Drainage and Flood Control District, Denver, CO.; November
l, 1980.

2.

Floodplain Information - BDulder Creek and
U.S. Army Engineer District, Omaha, Nebraska;

U.S. Army Corps of Engineer:
South Boulder Creek, ColoradD;
August, 1969.

3.

R.W. Beck and Associates: Major Drainageway Planning - South Boulder Creek;
Urban Drainage and Flood Control District, Denver, CO; December, 1973.

4.

Leonard Rice Consulting Water Engineers, Inc.: lOO-year Floodplain
Definition - Boulder and South Boulder Creeks - Vicinity of the Flatiron
Industrial Park; Backup Calculations and Information; November, 1977.

Federal Insurance Administration - U.S. Department of Housing and Urban
Development: Flood Insurance Study, Boulder County, CO. (Unicorporated
Areas); August, 1978.

Simons, Li and Associates, Inc: Major Drainageway Planning - Boulder and
South Boulder Creek Confluence Area; Development of Preliminary Plan - Phase
B; Urban Drainage and Flood Control District, Denver, CO; March, 1984.

5.

6.