WSP03901

• File Number: 8446
• Description: Cache La Poudre Platte Project
• State: CO
• Basin: South Platte
• Water Division: 1
• Date: 11/1/1962
• Author: BOR, DoI
• Title: Reconnaissance Report, cache La Poudre Unit, Colorado Peak Division, Missouri
• Water Supply Pro - Doc Type: Report/Study

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2000 the combined popuJ.ation of the two cities is expected to be
175,000 with a daily per capita use averaging 300 gallons. The
growth and use estimates are further explained in Part VI, "Municipal
and Industrial Water Supply." The year 2000 requirement determined
with the above estimates averages 58,800 acre-feet annually. When
compared with the estimated uJ.timate yield of the cities' existing
water rights of 42,800 acre-feet, a demand for an additional 16,000
acre-feet per year is indicated.

The proposed plan for the Cache la Poudre Unit consider the
follMng aspects of municipal water supply:

1. Consolidating the storage rights of Greeley I s mountain
reservoirs thereby enabling a full use of the rights
without extensive rehabilitation and operating expense.
2. ReguJ.ation through exchange of city allotments from the
Colorado-Big Thompson Project.
3. I'roviding the additional water supply required for
fUture municipal use by releasing 16,000 acre-feet of
stored surplus per year from Grey Mountain Reservoir.

Table 5 sununarizes the municipal function of the Cache la Poudre Unit.

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To serve the above municipal functions with a single-purpose
reservoir in the Cache la Poudre basin, a capacity of about 80,000
acre-feet would be required.

Increased municipal diversions will undoubtedly result in
increased return flows to the Cache la Poudre River. Greeley
increased return flows (an estimated 6,000 acre-feet per year) wouJ.d
enter the river near its mouth and wouJ.d pass out of the basin largely
unused. The several canal diversions (including inlets to Fossil Creek
and Timnath Reservoir) located below Fort Collins provide physical
control for return flows from that city. The follMng computation
was used in estimating the increased return flow from Fort Collins:

Annual diversion for Fort Collins
Return flow (65% of annual diversion)
Use of direct flow rights
Net increased supply from return flows

7,000
4,600
7,000

Future
(Year 2000)

33,600 11
21,900 0/
12,300 ~

Increase
(Difference)

26,600
17,300
5,300
12,000

(Units: Acre-feet)

Present

Y Diversion total from the direct flow rights, CBT allotments,
Cache la Poudre Unit water (if a.vailable) or other sources.
gj Average uJ.timate yield of Fort Collins direct flOlf rights.

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