FLOOD07738

• Designation Number: 538
• County: Arapahoe
• Community: Arapahoe County
• Basin: South Platte
• Title: Hydrology Addendum to FIS Arapahoe County and Incorporated Areas
• Date: 1/1/2001
• Prepared For: Aarapahoe County
• Prepared By: Montgomery Watson
• Floodplain - Doc Type: Floodplain Report/Masterplan

II
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I

STUDY AREA DESCRIPTION

Community Description
Arapahoe County is located in eastern Colorado, and is bordered by Adams County on the north,
Washington County on the east, Elbert and Douglas Counties on the south and Jefferson and
Denver Counties on the west. Littleton is the County Seat of Arapahoe County. The area
mapped in the FIRMs includes the entire county, including the incorporated communities of
Cherry Hills Village, Columbine Valley, Englewood, Glendale, Greenwood Village and
Sheridan. Populations and growth rates for the communities are shown in Table 1. The Cities of
Aurora and Littleton are partially located within Arapahoe County. However, because they are
not completely contained within the County, they each have a separate FIS governing
floodplains. The Towns of Bow Mar, Deer Trail and Foxfield are also located in Arapahoe
County. They are not covered by the FIS because there are no mapped floodplains within the
Towns' limits. The unincorporated areas of Byers, Peoria and Strasburg are not included because
they are not incorporated communities. The City of Centennial is not included specifically in the
FIS because it was not incorporated before the FIS was published. However, several areas of
Centennial are included in the FIS as unincorporated Arapahoe County.

Table 1. Arapahoe County Incorporated Communities Population
1990 1999 Growth
Community Population Population Rate
City of Cherry Hills Village 5,245 6,412 2,3%
Town of Columbine Valley 1,071 1,262 1.8%
City of Englewood 29,396 32,304 1.1%
Town 01 Glendale 2,453 3,102 2,60/0
City of Greenwood Village 7,589 14,021 7.1%
City of Sheridan 4,976 5,313 0.7%
Arapahoe County 391,511 488,367 2.5%

Notes:
(1) The table only includes communities in the county that are included in
this designation.

Watershed Description
Arapahoe County is located east of the Continental Divide in the South Platte River basin.
Elevations within the county range from approximately 6200 feet in the southern portion of the
County near Parker to 5250 feet in the western portion of the county along the South Platte. The
primary stream within the study area is the South Platte. Several streams flow from south to
north and are tributary to the South Platte either within or north of the county. Elevations of the
South Platte watershed exceed 14,000 feet. The tributary streams primarily originate along the
Palmer Divide, which has elevations approaching 8000 feet. The western portion of the county is
primarily urban development. The eastern portion of the county is urban development and
agricultural lands. The area has seen significant development over the last 10 years.

There are several current USGS gaging stations within Arapahoe County located along the major
rivers and tributary streams. In addition, there are several sites that have collected data but are no
longer active. Several of these gaging stations have been used to estimate peak discharges in the

5