FLOOD06925

• County: Larimer
• Community: Greeley
• Stream Name: Cache La Poudre River
• Basin: South Platte
• Title: Master Floodway Planning
• Date: 3/11/1983
• Prepared For: Greeley
• Prepared By: Simons Li & Associates Inc.
• Floodplain - Doc Type: Floodplain Report/Masterplan

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II. TECHNICAL APPROACH

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1. General Background

A floodplain information study for the Cache La Poudre River, Greeley,

Colorado, was prepared by the u.s. Army Corps of Engineers (COE), Omaha

District in March 1974. In this study, flood discharges at various locations

for various frequencies were determined. A hydraulic analysis utilizing COE's

in-house computer program was performed and the 100-year floodplain was

delineated using the flood elevations from the COE in-house computer program.

A flood insurnace study for the City of Greeley was prepared by FEMA in

January 1979. The flood insurance study adopted the flood discharges and the

100-year floodplain published by the COE in 1974. A floodway with one-foot

rise criteria was also established in the flood insurance study. The City did

not adopt a floodplain regulation and failed to enter the regular program of

the National Flood Insurance Program. In December 1981, the COE prepared

"Reconnaissance Report, Section 205, Cache La Poudre River, Greeley,

Colorado." A concrete-lined channel was proposed to mitigate the flooding

problem in this study reach.

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Because of recent development and development pressure along the Cache La

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poudre River floodplain within the study area, the City desires to enter into

a contract with an engineering firm for a master floodway plan of improvement

for the Greeley reach of the Cache La Poudre River. The objectives of the

study are:

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a.

To develop a floodway zone which will raise flood levels no
more than one foot and have an outer limit which will optimize
the use of floodplain area.

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b.

TO create effective use of limited public funds and enhance the
value of land and other property in the community.

c.

To formulate and evaluate alternative flood control and
drainage concepts to determine the most practical plan.

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d.

To prepare preliminary designs for the selected "Plan of
Improvement" which will include nonstructural and structural
measures and will provide sufficient information for easy tran-
sition to final design and construction.

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e.

To promote public health, safety, and welfare.

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