C153773 Feasibility Study

• Contract/PO #: C153773
• Contractor Name: Morrison, Town of
• Contract Type: Loan
• Water District: 9
• County: Jefferson
• Bill Number: HB 95-1155
• Loan Projects - Doc Type: Feasibility Study

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which begins with below average years of 1950,1955, and 1956, above average years of 1951
and 1953, the extremely dry year of 1954, and wet years of 1952 and 1957.

The model calculates the municipal water demand for variable buildout conditions with various
restrictions on lawn irrigation, watering efficiency, number of capita per EaR, and amount of
water used by each person per day. These inputs were varied to analyze the demand upon the
water system under different growth scenarios.

Using existing water usage data, the model was calibrated to existing build out conditions.
Morrison is presently using the amount of water needed to support 267 EaRs. Analyses
completed ten years ago assumed Morrison's development was 236 to 250 EaR. This model
further determined summer water use has been equivalent to irrigation of 25 acres total, or an
average of 4,000 square feet of lawn per EaR.

Design Criteria
For this model, the following criteria was imposed on the reservoir operation study:
1. An EaR is defined as housing three people, with each person using 100 gallons per day.
2. Each EaR has an average of 4,000 square feet of lawn.
3. The consumptive use of lawn bluegrass was computed by the Blaney-Criddle Method for
each year.
4. There is a reservoir capacity of 450 acre-feet in Cooley Reservoir available to Morrison
and 29 acre-feet in the Morrison Operating Reservoir for a total of 479 acre-feet.
5. Evaporation is based upon a total of 11 surface acres of water in the reservoirs (2.59
acres in the Morrison Reservoir and 8.4 acres in the Cooley Reservoir).
6. Seepage from the reservoirs was assumed to be 10 percent annually, as stated in the
Agreement with Cooley (Paragraph 3.12.3). However, this figure can easily be adjusted
in the model if further geotechnical information produces different seepage results.
7. Water rights yields would be limited by the terms and conditions of Morrison decrees.
8. For the modeled years, Morrison begins 1950 with an empty Cooley Reservoir but a full
Operation Reservoir.

Extrapolating the water demand criteria to additional development, and using water right yields
determined by a Bear Creek water rights computer model in 1985, the ability to divert water, fill
the Cooley Reservoir, and make releases from the reservoir were evaluated. The operations
model demonstrates that 1,290 EaR's can be served without shortages by fully utilizing all of
Morrison's water rights, except the Strain Gulch Reservoir assuming at least part of this water
right is transferred to the Cooley Reservoir.

7O-OSO.03S:MSI'R-PLN

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