PROJ00137

• Contract/PO #: C153467
• Contractor Name: Greeley, City of
• Contract Type: Loan
• Water District: 0
• County: Weld
• Bill Number: XB 99-999
• Loan Projects - Doc Type: Feasibility Study

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Table IV.7 shows the historic water levels in each of the reservoirs, based on
the gage height. This information was obtained from the Cache la Poudre River
Water Commissioner: Records were not available for every year, and in some
Cases are misleading. Whether or not a particular reservoir filled in a given
year was not always a function of the availability of water. The City's water
needs were balanced against the potential liability associated with reservoir
storage each year. This determined the desired storage and the maximum water
levels for much of the period of record. Some of the zero storage years were
a result of construction activities for rehabilitation of the dams, spillways,
and outlet works.

4.0 WATER UTILIZATION

Reservoir simulations were conducted for evaluating the firm yield and the
maximum yield for each project. The firm yield is the maximum quantity of
water which can be guaranteed during a critical dry period. The firm yield is
equivalent to the safe yield during a drought. In this analysis; the critical
drought occurred from 1953 through 1956. The maximum yield analysis assumed
the reservoirs would capture as much storable water as possible in the spring
and release their entire contents during the summer. This type of operation
allows maximization of the yield for each water right and full implementation
of the water exchange pl an wi th the North Poudre Irri gati on Company; Each
operating method has advantages.

Operating the reservoirs on a firm or safe yield basis, if they are not used
for exchange purposes, gi ves the City of Greel ey a dependabl e water supply
duri ng a drought. It al so provi des a year-round supply. One of the City's
problems during the winter is caused by the annual shutdown of Colorado-Big
Thompson Project conveyance facil i ti es, from November through March. Thi s
effecti vely el imi nates use of CBT or \~i ndy Gap water in the wi nter; An
exception to this operating policy is a possible water exchange plan developed
between the Water Supply and Storage Company and the Ci ty, whi ch exchanges
Wi ndy Gap or CBT water for storage water in Chambers lake. By refilli ng
Barnes Meadow Reservoir in the fall, with water held in Chambers lake, the
City would obtain a reliable winter water supply. Currently, the City relies

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