FLOOD10696

• County: Larimer
• Community: Larimer County and Incorporated Areas
• Title: FIS - Larimer County and Incorporated Areas - Vol 1
• Date: 12/19/2006
• Prepared For: Larimer County and Incorporated Areas
• Prepared By: FEMA
• Floodplain - Doc Type: Historic FEMA Regulatory Floodplain Information

The Cooper Slough study reach is approximately 1.5 miles long. The tributary area for the
Cooper Slough basin is approximately 10.2 square miles (Reference 9). The basin is
approximately 6 miles long and 1.75 miles wide, and is fairly flat, with poorly defined
drainage patterns. Cooper Slough flows in a southerly direction and joins Boxelder Creek
in the vicinity of Prospect Street and 1-25, east of the City of Fort Collins.

The Dry Creek study reach is approximately 1.9 miles long. The stream is a tributary of
the Cache La Poudre River, which flows from the northwest in a southeasterly direction to
its confluence with the Cache La Poudre River on the eastern corporate limits of the City
of Fort Collins. Over 500 structures are located within the base floodplain in the City of
Fort Collins. The total number of structures throughout the Dry Creek floodplain for both
County and City areas was estimated as over 800 structures in 1995 (Reference 63). The
channel is approximately 3 to 4 feet deep and 10 to 15 feet wide from the downstream limit
to Andersonville, after which the channel is basically nonexistent to the upstream limit of
the study. The stream channel gradient within the study reach is approximately 18 feet per
mile. The soils within the Dry Creek basin floodplain are of the Fluvaquents-Fluvents and
Otero-Nelson Associations (Reference 4).

The Town of Johnstown
The Town of Johnstown is located in the eastern portion of Larimer County and the
western portion of Weld County. The town is approximately 20 miles south-southwest of
the City of Fort Collins.

The population of the Town of Johnstown has grown from 1,579 in 1990 to 3,829 in 2000
(Reference 61).

The Big Thompson River flows easterly through the top portion of the town located in
Larimer County.

The City of Loveland
The City of Loveland is located in eastern Larimer County, approximately 8 miles east of
the mouth of Big Thompson Canyon and the Rocky Mountains. The city is approximately
42 miles north of Denver and 8 miles south of Fort Collins.

The City of Loveland is growing at a rapidly increasing rate having more than tripled in
size from a population of 9,734 persons in 1960 to populations of 16,220, 30,244, and
50,608 persons in 1970, 1980, and 2000, respectively (References 2 and 61). The economy
of the area is basically commercial and agricultural.

The Big Thompson River flows easterly through the southern end of Loveland from the
high mountains of the Colorado Front Range. The river is steep and narrow through the
mountains and canyon; however, once it enters the plains just west of Loveland, it widens
with a meandering flow.

Within the corporate limits of Loveland, the Big Thompson River channel is approximately
100 feet wide and from 6 to 10 feet deep. The streambed, gravelly in composition, has an
average channel slope of 18 feet per mile. The flood plain is from approximately 2000 to
3000 feet wide in this area and relatively flat.

13