FLOOD10381

• Designation Number: 591
• County: Broomfield
• County: Broomfield
• Community: Broomfield
• Title: FIS - Broomfield
• Date: 8/18/2004
• Prepared For: Broomfield and CWCB
• Prepared By: FEMA
• Floodplain - Doc Type: Current FEMA Regulatory Floodplain Information

The areas studied by detailed methods were selected with priority
given to all known flood hazard areas and areas of projected
development or proposed construction through March 1990.

The scope of study was revised to describe the following streams
that were studied by approximate methods:

Mustang Run
Preble Creek
South Fork Preble Creek
Sack Creek South

This flood hazard information was provided by the u.s. Department of
the Interior, Bureau of Reclamation, under Inter-Agency Agreement
No. EMW-90-E-3456, as part of the Limited Map Maintenance Program.

2.2 Community Description

Broomfield is located in north-central Colorado, on the eastern
slope of the Rocky Mountains, approximately 13 miles north of
Denver. In 1970, the population of Broomfield was 7,161; at the end
of 1980, the population was 20,730. The 2000 population was 38,272
(Reference 1). Continued growth is expected for the City of
Broomfield.

City Park Channel, Nissen Reservoir, Gay Reservoir, and the
West Lake Reservoir drain a total area of approximately 8.4 square
miles (sq. rni.) and are bounded on the northwest by a rise at an
elevation of approximately 5,400 feet. The streams generally flow
southeasterly, emptying into Big Dry Creek at an approximate
elevation of 5,200 feet. The drainage boundaries of the individual
basins are indistinct, being located at the crests of the east-west
rolls of the high plains. The creeks are generally shallow, with no
distinct channels.

The climate of the area features low relative humidity, low
rainfall, moderate to high winds, and a large daily range in
temperature. Temperatures range from a high of 102 degrees
Fahrenheit (OF) to a low of -260F at Rocky Flats. The average
maximum and minimum temperatures are 60.20oF and 39.10oF,
respectively. The average annual precipi tation at Rocky Flats is
15.14 inches. Sixty-nine percent of the precipitation occurs
between April and September. Summer precipitation is largely from
thunderstorm activity and is sometimes extremely heavy.

Typical area soils are composed mostly of the Nunn, Platner, and
Renshill series, as defined by the U. S. Soil Conservation Service
(SCS). These soils are generally well drained and nearly level to
moderately sloping formations of loamy alluvial material. Slopes
vary from 0 to 9 percent, and the natural vegetation is grass,
although most undeveloped areas are cultivated. The permeability of
these soils is moderate to slow (Reference 2).

Land use within the drainage basins consists
commercial and residential development with
open-space areas.

of a
several

mixture
parks

of
and

3