WSP05120

• File Number: 8200.760
• Description: Yampa River General
• State: CO
• Basin: Yampa/White
• Water Division: 6
• Date: 1/1/1983
• Author: USGS
• Title: Reservoir Development Impacts on Surface-Water Quantity and Quality in the Yampa River Basin - Colorado and Wyoming - 1983
• Water Supply Pro - Doc Type: Report/Study

By D. Briane Adams, Daniel P. Bauer, Robert H. Dale,
and Timothy Doak Steele

RESERVOIR-DEVELOPMENT IMPACTS ON SURFACE-WATER QUANTITY AND QUALITY
IN THE YAMPA RIVER BASIN, COLORADO AND WYOMING

ABSTRACT

The Yampa River basin in northwestern Colorado and south-central Wyoming is
an area in which development of the coal resources and associated economy is ac-
celerating. This development includes increased use of the water resources of the
area, which will have a direct Impact on the quantity and quality of the water
resources.

Current (1979) regulation of the basin's surface water by reservoirs is mini-
mal. As part of 18 surface-water projects, 35 major reservoirs have been proposed
with a combined total storage of 2.18 million acre-feet (2,688 cubic hectometers),
which is 41 percent greater than the mean annual outflow from the basin.

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Three computer models were used to demonstrate a method of evaluating future
impacts of reservoir development in the Yampa River basin. Four different reser-
voir configurations were used in the analysis in order to simulate the effects of
different degrees of proposed reservoir development.

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A multireservoir-flow model included both within-basin and transmountain
diversions. SimulatIons Indicated that in many instances the proposed diversion
amounts would not be available for either type of diversion. For example, a
proposed industrial diversion of 130 cubic feet per second (3.64 cubic meters per
second) from the proposed Blacktail Reservoir wouid not be possible from 85 to
93 percent of the time. A corresponding frequency analysis of various reservoir-
storage levels indicated that most reservoirs would be operating with small per-
centages of total capacities, and, in most instances, with less than 20 percent of
conservation-pool volumes.

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Simulations using a dissolved-sol ids model indicated that extensive reservoir
development could Increase average annual concentrations at most locations. At
Steamboat Springs, Colo., for example, most upstream water could be diverted,
which could result in Increased dissolved-sol ids concentrations during an average
water year. Extensive reservoir development could reduce the larger Mayor June
maximum mean monthly flows at Deerlodge Park, Colo., which is located downstream
from the confluence of the Yampa and the Little Snake Rivers, from 460,000 to
250,000 acre-feet per month (567 to 308 cubic hectometers per month) and could
Increase the mean annual dissolved-solids concentrations by 60 percent.

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