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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Planning of Upper Westerly Creek Area OUtfall System

The upper Westerly Creek area outfall system planning involved iden-

tifying existing and potential drainage problems through a hydrologic and

hydraulic analysis of the outfall drainageway system. Several alternative

drainage plans were developed including schematic layouts and preliminary cost

estimates. The hydrologic analysis included use of EPA's Storm Water

Management Model (SWMM) and CURP outlined in the "Urban Storm Drainage

Criteria 1 Manual," Urban Drainage and Flood Control District. The hydraulic

computations provided for definition and justification of proposed improve-

ments, determination of capacity of proposed conduits, culverts, reservoirs,

and channels, cost of each alternative, and required right of way. After

review of all drainage alternatives, the best alternative drainage plan was

selected and a preliminary design done. Each alternative was also evaluated

considering operation and maintenance aspects of each.

Typical plans, profiles, and cross sections, conduit sizes and detention

pond sizing will be developed for the best alternative plan.

The drainage system was designed to convey the 2-3/4 year storm runoff

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and basinwide or on-site detention requirements for the 100-year storm. The

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100-year discharge was limited to the lOa-year peak flow at the rate that

would occur from undeveloped land.

Project Period: October 1981 through March 1982

Project Budget: $16,000

Reference: Mr. Ben Urbonas
Chief, Master Planning Program
Control District
Urban Drainage and Flood Control District
2480 W. 26th Street, Suite 156B
Denver, Colorado 80211
[phone]

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