7344

• UCREFRP Catalog Number: 7344
• Author: Veenhuis, J. E. and D. E. Hillier.
• Title: Impact of Reservoir-Development Alternatives on Streamflow Quantity in the Yampa River Basin, Colorado and Wyoming.
• USFW Year: 1982.
• USFW - Doc Type: Lakewood, Colorado.
• Copyright Material: NO

Consumptive Use and Existing Surface-Water Diversions

Analyses of existing surface-water rights and diversions indicate that more
than 90 percent of the water withdrawals and 96 percent of the consumptive use of
water in northwestern Colorado during 1976 were attributed to agricultural irriga-
tion (Knudsen and Danielson, 1977; Gray and others, 1977). Most records of diver-
sions to hay and wheat fields and pasturelandsin the basin are incomplete. How-
ever, incremental inflows between control points accounted for the effects of most
of these diversions on streamflow. Diversions through the Gibraltar Canal from the
Yampa River near Hayden, Colo., were documented and were included in the reservoir
analysis (table 2).

Reservoir Geometry

Data regarding the geometry of the proposed reservoirs were obtained from
Herbert Dishlip (U.S. Bureau of Reclamation, written commun., 1977). Reservoir
data obtained included water-surface elevation versus surface area and volume and
some preliminary estimates of active storage volumes (conservation pool minus dead
storage) for each reservoir. Outflow elevations were generally not available, so
estimates were made for dead-storage or conservation-pool elevations. The amount
of active storage available for downstream needs was not specified; therefore, for
the 100-percent allocation, all available reservoir storage was distributed
through the water year. Thus, the 100-percent allocation for each reservoir
option represented use of the reservoirs' total active storage volume for
diversion purposes.

ALTERNATIVE RESERVOIR CONFIGURATIONS STUDIED

Because it was not economically feasible to model all possible configurations
of the 35 proposed reservoirs, 4 representative reservoir-development options for
17 of the larger proposed reservoirs were chosen as summarized in table 3; the
locations of the reservoirs and control points are shown in figure 1. These op-
tions, the same as those used in the U.S. Geological Survey's Yampa River basin
assessment, include the largest proportion of the total reservoir storage proposed
for the basin (Adams and others, 1982). Using these options, a representative
expected range in flow may be simulated for various degrees of reservoir
development.

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