FLOOD04323

• County: Larimer
• Community: Greeley
• Stream Name: Cache La Poudre
• Basin: South Platte
• Title: Cache La Poudre Floodplain Update
• Date: 9/27/1984
• Prepared For: Greeley
• Prepared By: Simons Li & Associates Inc.
• Floodplain - Doc Type: Project

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4105 EAST FLORIDA AVENUE
SUITE 300
DENVER. COLORADO 80222

TELEPHONE [phone]

September 19, 1984

Ms. Ann W. Jamison
Planner II
City of Greeley
Civic Center Complex
919 - 7th Street
Greeley, Colorado 80631

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Re: Assessment of Encroachments to Cache la Poudre River
Floadway

Dear Ann:

Simons, Li & Associates, Inc., has completed an assessment of the
impacts to the Cache 1 a Poudre Ri ver Fl oodway caused by recent or
planned construction of structures. A listing of structures and
river station is given in Table 1. The procedure used to assess any
impact is outlined below:

~ 1. Identi fy buildins locations (based on site plans
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~ suppl i ed by the Clty).
, 2. Determi ne appropriate cross section to be modi fi ed.
3. Add new "map-interpolated" cross sections where
necessary to provide ba~line conditions.

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4. Model baseline conditions using original U. S. Army
Corps of Engineers (C.O.E.) data and new map.
i nterpol ated cross secti ons (see HEC-2 output,
Attachment 1).

5. Examine original C.O.E. cross sections and modify
locations where structures existed at the time of the
C.O.E. study.

6. Model floodplain and floodway using C.O.E. data as
modified to reflect older structures (see HEC-2
output, Attachment 2).

7. Modi fy cross secti ons to refl ect recent or pl anned
structures within floodway by blocking out the area of
the structure perpendicular to the flow direction.

Cheyenne, lilY . Colorado Springs, CO . Fort Collins, CO . Newport Beach. CA
PittSburgh. PA . Salt Lake City. UT . Tucson, AZ . Washington. D.C.

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