PROJ00118

• Contract/PO #: C153670B
• Contractor Name: Ute Water Conservancy District
• Contract Type: Loan
• Water District: 72
• Bill Number: SB 88-30
• Loan Projects - Doc Type: Feasibility Study

I

I.
I

I

I

I

I

I

I

..

I

I

I
I

I

I

I
{'

I

The methodology involves selection of a historic period of operation that

includes both extremely dry and wet years, one for which significant historic

data exist, and a period that can be used to project probable future conditions.

The historic period proposed for this study is 1965 through 1984. This period

includes a comparatively dry series of years including 1977 (the dryest year of

record) and two of the wettest years of record. Records for this period are

relatively complete and represent the effect of current development

most importantly the Collbran Project. Flow in Plateau Creek was significantly

affected by this water project.

The amount of water historically flowing at each diversion point will be

determined from USGS gage records and Water Commissioners' records. The amount

of water that might reasonably be taken by upstream senior decrees that was not

fully utilized during the study period will be subtracted from the gage records.

Allowance will be made for intervening inflows and net demand from downstream

decrees. The safe yield will be determined by considering combinations of flow

at various points of diversion until the Jerry Creek Reservoirs are drained

during the most critical period.

Certain reasonable assumptions will be made to complete the study. These

include: the level of water demand, with the exception of the District, has

been constant throughout the study period due to its fixed, agricultural nature;

senior absolute decrees divert at the decreed amount unless otherwise known; the

Molina Power plant operates according to USBR criteria; the senior decrees on Big

Creek/Cottonwood Creek callout Molina Power plant only when Vega Reservoir is

depleted; minimum flow requirements in Plateau Creek create defacto senior

rights; Grand Valley Irrigation Company can impose a valid call on the Colorado

River and Plateau Creek when flow in the river below Plateau Creek drops to 640

cfs; and the State Engineer's basin rank number may be used to establish

priority between decrees. The end product will be a summary of the study

procedure and a tabulation of the operation conditions and safe yield.

B.

Domestic Water Demand:
The obj ective is to determine the demand for water within the District's