PROJ00072

• Contract/PO #: C153592
• Contractor Name: West Divide Water Conservancy District
• Contract Type: Loan
• Water District: 0
• County: Garfield
• Bill Number: SB 89-85
• Loan Projects - Doc Type: Feasibility Study

i

I

I

these diversions does not equal the total of adjudicated rights on record, they

fully utilize all but the peak of spring runoff. To increase diversions during

flood season would require enlargement of existing ditches. Further, peak

diversions already exceed what may normally be considered a full diversion

requirement for the approximately 1,600 acres of irrigable land served by East

Divide ditches. Therefore, in the determination of storable inflows, an average

historic diversion demand has been subtracted from recorded amounts at the East

Divide gauge. When gaged flows exceed diversions, storage can be made in

Alsbury reservoir. Table 4.3 summarizes the determination of storable inflows

for the period of record of the East Divide gauge. This period included both

above and below average years, with 1963 being much below average. A review of

the Buzzard gauge records shows 1963 to have been the critical year for the

period of its record, which does not, however, include the extremely dry year of

1977. A comparison between 1963 and 1977 for the gauge on West Divide Creek (at

elevation 7050) indicates that April runoff in 1977 was 65% of that in 1963.

I

I

I

I

I

I

I

The calculations summarized on Table 4.3 indicate average annual storable

inflows of 412 acre-feet -- varying from a maximum of 745 acre-feet in 1962 to a

minimum of 132 acre-feet in 1963. The probable storable inflow for 1977 is

estimated to be 115 acre-feet, on the assumption that April storable flow would

be 60% of that for 1963 and that winter base flow would be essentially constant.

Based on the foregoing analysis, the Project will yield 250 acre-feet of water

per year with a less than 10% chance of shortage in any given year. The Project

has therefore been developed on the basis of a probable safe yield of 250

acre-feet.

I

I

I
I

I

It will be noted that diversions in June generally use the entire flow of

the creek and still are inadequate to provide a full supply. The water

commissioners' records indicate that shortages regularly occur on the creek

beginning about June 15.

I

Calls on the Colorado River will not affect the ability to store water at

Alsbury Reservoir for two primary reasons: First, any call outside the spring

runoff season would be futile since the small amount of base flow rising in the

upper reaches of the stream evaporates or seeps into the ground before it

I

I

-7-

I

-