FLOOD09485

• Designation Number: 206
• County: Larimer
• Community: Fort Collins
• Stream Name: Fossil Creek Drainage Basin
• Basin: South Platte
• Title: Master Drainageway Planning - Fossil Creek Drainage Basin, Fort Collins, Larimer County, Colorado
• Date: 8/1/1982
• Designation Date: 1/1/1983
• Floodplain - Doc Type: Floodplain Report/Masterplan

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11.3 Plan Implementation

Implementation of the recommended plan should be carried out in a sequen-

tial manner. Maintenance improvements should be performed first. The main-

tenance type improvements would be the improved headwall at the Union Pacific,

riprap along the south bank of Fossil Creek near Portner Reservoir, stabi-

lizing the upstream wingwall on the C&S Railroad crossing at Fossil Creek, and

evaluating and improving, if necessary, the riprap on the downstream embank-

ment of Fossil Creek Drive. The second phase of improvements should consider

placing riprap do"mstream of culverts and along any banks where there are sud-

den changes in flow direction. If a culvert is to be replaced, the riprap

downstream of the culvert sbould be sized for the improved culvert and

replaced at the time of the improvement.

Major channel system improvements should occur from the downstream to

upstream. This is because currently minor problems exist along the upstream

reaches, the reaches are relatively stable, and there is limited pressure for

development. The reach between Fossil Creek Reservoir and the Union Pacific

Railroad experiences flooding and ponding behind County Road 11 during very

frequent events. To be developed the reach must be channelized. Part of the

reach between the Union Pacific Railroad and Mail Creek is currently platted.

Improvements should proceed with the development. The items of priority

should be the enlarged channel crossing at Lemay Avenue (County Road 13) and

the erosion control check downstream of Lemay Avenue. The erosion control

check will help stabilize this reach and prevent bank sloughing. Downstream

of Lemay, the outlet and channel should be riprapped. Also, if there is a

Gharp change in flow direction and the north, downstream bank should be ade-

quately protected. The improvements at Tr ilby Road (County Road 34) are

costly and much of the land is required for a pond. The improvements should

be made as funding is available. The next item of priority is the erosion

control check below Shields Street and the culvert improvement. This channel

section is degrading and the downstream control is not until the pond above

Fossil Creek Drive. The erosion control check between Highway 287 and the C&S

Railroad is required to prevent further degradation and bank sloughing. Here

the downstream control is Highway 287 and when there is to be development or

there is a desire to limit the bank sloughing, then this erosion control check

should be constructed. The culvert improvements and erosion control checks

along the tributaries should take place as development occurs.

Low flow channels are recommended near the culvert entrance of the
natural detention areas.

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