4203

• UCREFRP Catalog Number: 4203
• Author: Colorado River Water Conservation District.
• Title: Summary of Issues and Preliminary Hydrologic Assessment of the Agreement to Subordinate the Shoshone Hydropower Water Right.
• USFW Year: 1986.
• USFW - Doc Type: \
• Copyright Material: NO

N
PRESENT OPERATION.

At present, Public Service Company makes diversions of at least 1,250 cfs
whenver the water is available. During the non-irrigating season (approximately
October 15 - April 15) river flows often fall below the decreed diversion amount
and remain low for months (see attached graph). This is the period of the most
significant "call" placed by the water right. The fact that Shoshone is;short of
water through most of the winter means that all upstream junior water uses should
be curtailed until the natural flow of the river again satisfies the decreed
diversion amount. This historic winter season demand has made it necessary for
municipalities and industrial water users to create augmentation plans which
allow combined use of stored water and converted agricultural water rights in
providing a firm year round water supply.
The Shoshone demand remains throughout the historic irrigation season, and
as a general rule, if enough water is in the river to meet the Shoshone demand,
then there is also enough to meet the combined Cameo demand downstream. The
irrigation season demand at Cameo is composed of several very senior irrigation
and power rights which serve Grand Valley agricultural water users. The
irrigation season demand at Cameo dates from the 1880`s and represents the single
most important control point on the Colorado River. When there is not enough
water in the Colorado River to meet the 1,250 cfs Shoshone demand during the
early or late irrigation season, the Division 5 Engineer is informed of the
shortage and calls for water to be released from Green Mountain Reservoir
pursuant to the terms of Senate Document No. 80. He also halts out-of-basin
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