FLOOD00155

• County: Boulder
• Community: Boulder County
• Stream Name: Upper Boulder Creek, Fourmile Creek
• Title: Floodplain Information Report
• Date: 12/1/1981
• Prepared For: Boulder County
• Prepared By: UDFCD
• Contract/PO #: &&
• Floodplain - Doc Type: Floodplain Report/Masterplan

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Purpose and Scope

This report was prepared to guide local officials in planning the use

and regulation of the floodplain areas such that flood hazards and future

Related Flood Studies

flood damages are minimized.

It includes information on historical

Information on past floods was obtained from the Corps of Engineers,
Omaha District and the U.S. Geological Survey publication entitled
"Floods in Colorado" (Reference 1).
Previous floodplain studies have been completed on Boulder Creek
downstream from the reach covered in this report. These include two

floods, existing factors which influence the flood hazard, and the nature

and extent of probable future floods.

The report data includes flooded area maps delineating the 100-year

flood boundary and flood profil es showing the water surface e levat ions

for the 10-, 50-, 100-, and 500-year floods.

Supplemental material to this report in the form of technical back up

includes the supporting engineering and hydrologic data which may also be

studies by the Corps of Engineers, Omaha District:

"Floodplain

Acknowledgements
The assistance and cooperation of the individuals, agencies, and

Information, Boulder Creek and South Boulder Creek, Volume II, Boulder
Metropolitan Region, Colorado", August 1969 (Reference 2); and "Special
Flood Hazard Information Report, Boulder Creek, City of Boulder,
Colorado", May 1972 (Reference 3).
In addition, Boulder Creek was included in the City of Boulder Flood
Insurance Study published in 1978.
This Floodplain Information Report for Upper Boulder Creek and
Fourmile Creek is the only detailed study completed to date for the

used in the location and design of roads, bridges, and channel
modifications.

particular reaches covered herein and is, therefore, authoritative.

firms listed below was appreciated and is gratefully acknowledged.

Benchmark Mapping Services - Denver, Colorado
Larry Buss - U.S. Army Corps of Engineers, Omaha District
Larry Cieslik - U.S. Army Corps of Engineers, Omaha District
Larry F. Lang - Chief, Flood Control and Conservation Section,
Colorado Water Conservation Board
D. Randolph Seaholm - Water Resources Specialist, Colorado Water
Conservation Board
Mike G. Serlet - Public Works Department, Boulder County, Colorado

Maps and Surveys
Cross-section data and topographic maps at a scale of 1: 1200 and
having a contour interval of two feet were prepared by Benchmark Mapping
of Denver by photogrammetric methods from fl ights made on October 26,
1977 (Reference 4). These data were supplied by the Colorado Water
Conservation Board and Boulder County. U.S. Geological Survey 7.5 minute
series topographic maps with 40-foot contour intervals at a scale of
1 :24,000 were also used in the study (Reference 5). Bridge data was
supplied by the Corps of Engineers and Boulder County. Control monuments
exist in the field for use in relating actual ground data to information
contained in the report (see Table 5).

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