9303

• UCREFRP Catalog Number: 9303
• Author: U.S. Bureau of Reclamation.
• Title: Price River Cumulative Hydrology Study.
• USFW Year: 1998.
• USFW - Doc Type: Provo, UT.
• Copyright Material: NO

J'rice River Cumulative Hydrology Study

As part of the updated biological opinion for the Price - San Rafael Salinity Control Project, the
Bureau of Reclamation (Reclamation) committed to conduct a cumulative hydrology study for
the Price River. The U.S. Fish and Wildlife Service (Service) has committed to issue a new
biological opionion for the proposed Narrows Project using the results of the cumulative
hydrology study.

In preparation of the cumulative hydrology study, Reclamation reviewed previous hydrologic
models that had been cumpleted for the Price - San Rafael Salinity Control Project and the
Narrows Project. The Price - San Rafael Salinity Control Project report states:

The State of Utah has been apportioned 23 percent of the total quantity of consumptive
use available for use each year by the Upper Colorado River Basin under the Colorado
Compact. Depending on the assumption made, this represents an annual supply of 1.32
to 1.4 million acre-feet. All but approximately 80,000 acre-feet/year of Utah's Colorado
River allocation has been apportioned. At present, the filings for this unappropriated
water total approximately 4 million acre-feet/year. Of this total, approximately 245,000
acre-feet/year is in the Price River Basin and approximately 570,000 acre-feet/year is in
the San Rafael River Basin. Extreme care must be exercised when considering water
rights and water filings. Because of the wide variations in streamflow and physical
limitations in diversion capability flow rights and filing tend to overstate the actual
amount of water which could be diverted. I

After considering this statement, Reclamation made the assumption that the cumulative
hydrology study should be based primarily on the total annual depletion that the proposed and
existing federal projects have on the Price River Basin.

There are two existing and one proposed federal projects that impact the Price River Basin. They
are the Price-San Rafael River Salinity Control Project, Scofield Reservoir and the proposed
Narrows Project. The annual depletion of the Narrows Project from the Price River is 5,709
acre-feet and the ann':lal depletion of the Price-San Rafael River Salinity Control Project from the
Price River is 25,31O'acre-feet. The total depletion that.Scofield Reservoir has on the Price River
was based on the historical diversions below Scofield Dam. These diversions were identified by
Mark Page (Area Engineer, State of Utah, Division of Water Rights). The diversions are
87,848.9 acre-feet for the 1968 average water year, 30,415.3 acre-feet for the 1977 dry water
year, and 88417.8 acre-feet for the 1984 wet water year. However, these diversions do not
account for the amount of water that makes its way back into the Price River (return flow). The
State of Utah reports that consumptive use is 63 percent. Therefore, Reclamation assumed the
return flow to be 35 percent of the total diversion.

Phase I Report, Salinity Investigation of the Price - San Rafael Rivers Unit,
Colorado River Water Quality Improvement Program (U.S. Bureau of
Reclamation, Department of the Interior, 1984 ) IV-I.