FLOOD01785

• County: Larimer
• Community: Fort Collins
• Stream Name: South Platte Tributaries
• Title: Hazard Mitigation 404 Grant Application Floodproofing
• Date: 9/1/1999
• Prepared For: Larimer County
• Prepared By: Fort Collins
• Floodplain - Doc Type: Miscellaneous

City of Fort Collins

Hazard Mitigation 404 Grant Application

Construction Phase- Authorized work will be executed by the contractor selected
by the homeowners. The contractor will be responsible for any and all necessary
permits for the work

Observation/Certification Phase- To verify the work was performed to the
anticipated standards, City staff or consultants will provide field observations and,
if necessary, provide a punch list of items to be corrected prior to final payment.

Subsidy Payment Phase- If the project has satisfied the conditions of the
agreement and passed the field observations, the City will complete payment to
the contractor or homeowner.

B. Description of the Problem

This section describes the drainage basins that impact Fort Collins and their associated
flooding history- The list also includes potential types of flooding in Fort Collins: I)
drainage basin, 2) dam failure, and 3) loca] flash flooding_

r Cache La Poudre River

The drainage area of the Poudre River above Fort Collins in the Rocky
Mountains is approximately ],129 square miles. The steep drainage basin
and channel make the Poudre River subject to flash flooding_

Notable floods occurred on the Cache La Poudre River in 1844, 1864,
1884, 1891, 1904, 1923, 1930, 1938, 1951, 1961, 1983, and 1995. The
three largest floods occurred in 1864, 1891, and 1904; the flood peak of
1904 was approximately 57,000 cubic feet per second (cfs). During the
1904 flood, approximately 150 houses were swept away, and all the
bridges were destroyed except one. Nearly $150,000 (1904) in damage
occurred within Larimer County in that flood, and two residents lost their
lives. The April 30, 1999 flooding was approximately a 10-year event.
The estimated discharge was approximately 8,000 cfs at the Poudre River
at the Lincoln Street gage in Fort Collins.

Most floods on the Cache La Poudre River within Fort Collins and the
plains area of the basin have caused damage to crops, livestock, fann
improvements, machinery, irrigation structures, and road and railroad
structures. Only the largest floods have caused damage to residential,
commercial, and industrial property in Fort Collins_ The April 30, 1999
flood caused some damage to bike trails, but their was no damage to
residential or commercial structures.

2_ Spring Creek

Spring Creek is a right bank tributary to the Cache La Poudre River and
flows from west to east through Fort Collins_ The Spring Creek basin has
a drainage area of 30 square miles. The upper 18 square miles of the basin

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