FLOOD00191

• Designation Number: 464
• County: Larimer
• Community: Fort Collins
• Title: Flood Insurance Study - Fort Collins, CO, Larimer County
• Date: 2/1/1984
• Designation Date: 5/1/1998
• Floodplain - Doc Type: Floodplain Report/Masterplan

2.0 AREA STUDIED

2.1 Scope of Study

This Flood Insurance Study covers the incorporated area of the City
of Fort Collins, Larimer County, Colorado. The area of study is
shown on the Vicinity 11ap (Figure 1). Areas not included in this
study include portions of Larimer County within the corporate limits
of Fort Collins.

Floods caused by overflow of Spring Creek, Spring Creek Overflow,
Dry Creek, and the Cache La Poudre River were studied in detail.

Those areas studied by detailed methods were chosen with considera-
tion given to all proposed construction and forecasted development
through 1982.

2.2 Community Description

The City of Fort Collins is located in eastern Larimer County, in
north-central Colorado, and is approximately 60 miles north of
Denver. More specifically, Fort Collins is 12 miles north of Loveland,
15 miles west of Ault, and 9 miles southwest of Wellington.

Fort C~llins became incorporated in 1873 and has grown rapidly, from
approximately 1,376 residents in 1880 to an estimated 56,800 in 1975
(References 1 and 2) .

The climate in Fort Collins is typical of the eastern foothills of
the Rockies. The mean annual temperature is 480F, with the warmest
month being July (70.80F) and the coldest month being January (26.80F).
The average annual precipitation in Fort Collins is 14.94 inches
(Reference 3). The vegetation found along streams consists mainly
of buffalo grass and cottonwood trees.

The Cache La poudre River study reach is approximately 6.3 miles
long. The stream flows southeasterly along an area north and east
of Fort Collins. The development along the Cache La poudre flood
plain is very minor at the present time, with only a few residential
and commercial structures. The channel in the study reach averages
160 feet wide and 7.0 feet deep, with the gradient varying from 28
feet per mile from the upstream corporate limits to State Highway 14,
and 16 feet per mile from State Highway 14 to the downstream corporate
limit (Reference 1). The soils within the Cache La poudre study
reach consist of Fluvaquents-Fluvents Association (Reference 4) .

The Spring Creek study reach is approximately 5.5 miles long. The
stream is located in the southern half of the city and flows from west
to east and generally follows Prospect Street. The channel averages
15 feet wide and 4 feet deep, with gradient varying approximately 31
feet per mile. The Spring Creek basin is approximately 50 percent
developed and consists primarily of residential structures, with

2