FLOOD03676

• Designation Number: 519
• County: Weld
• Community: Greeley
• Stream Name: Cache la Poudre River
• Basin: South Platte
• Title: Floodplain Study - Cache la Poudre River, Greeley, Weld County, Colorado
• Date: 10/1/1999
• Designation Date: 5/1/2000
• Floodplain - Doc Type: Floodplain Report/Masterplan

1.0 STUDY PURPOSE AND AUTHORITY

This study was to develop new hydraulic modcls reflecting current conditions on the

Cache La Poudre River in Weld County, Colorado, to compute new flood water SUrfilcc profiles,

ddineate flood boundaries and a flood way. The study also included areas within the limits of

the City of Greeley, The results of this study can he used by the City and COLlnty f'Jr purposes of

f100d plain management

The study was done undcr authority of Section 206 of the Flood Control Act of 1960 as

amended, commonly caUed the Flood Plain Management Services Program. The study was

conductec. in response to a request from the Colorado Wat,?r Conservation Board in cooperations

Wil:h the City of Greeley and Weld County..

2.tO' STUDY AREA

TLe Cache La Poudre River is a left bank tri.bmary of the South Platte River which joins

the Platte River in Weld County approximately 3 miles eao;t of Greeley, New hydraulic analyses

including f100d water surface profiles and flood boundaries were developed for the Cache La

Po Jdre River from the South Platte confluence to Ash AVCllue near Greeley and from 25th

A venue a1 Greeley to Weld COUllty Road 23 near Windsor, Between Ash A venue and 25th

Avenue an existing hydraulic study was adapted for this slJdy.

3.0 PREVIOUS STUDIES
Several previous studies developed flood water surface profiles and flood boundaries for
portions of the Cache La Poudre River in Weld County. I tlformation on flooding on the Cache
La Poudre River in the vicinity of Greeley have been published hy the Federal Emergency
M2.nagement Agency (FEMA) in the Flood Insurance Studies (FIS) for the City of Greeley
(Referenel~ 1) and Weld County (Reference 2). FElvlA abo had a detailed f100d plain study
conducted for the Cae:he la Poud:e River in the vicinity of the town of Windsor with the results
published in the City of Windsor FIS (Reference: 3) and the Wcld County FIS. More recently. in
191)7, a hydraulic analysis for the Cache La Poudre River reach through the City of Gret:ley was
done for the City by a consultant (Reference 4),

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