7750

• UCREFRP Catalog Number: 7750
• Author: U.S. Bureau of Reclamation.
• Title: Study of Alternative Water Supplies for Endangered Fishes in the "15-Mile Reach" of the Colorado River.
• USFW Year: 1992.
• USFW - Doc Type: \
• Copyright Material: NO

CHAPTER I
INTRODUCTION

(3) Purchase of existing agricultural water rights from willing sellers. Once
purchased, the Colorado Water Conservation Board would apply for the necessary
water right changes. These changes would result in instream flow rights;
(4) Relocation of the point of diversion of some of the water diverted to the Grand
Valley irrigation systems downstream so that more water would remain in the 15-Mile
Reach than is there presently;
(5) Improvement of irrigation efficiency in the Grand Valley so that river diversions
could be reduced, thereby leaving more water in the 15-Mile Reach than there is now;
and,
(6) Consideration of miscellaneous alternatives (e.g., ground water pumping to
provide supplemental flows and importation of water to the Colorado River
mainstem).
It is anticipated that the results of this study will be used to select the most promising
alternatives for more detailed analyses. At this point, however, no decisions have been
reached as to whether further studies will be pursued. It should also be emphasized that any
alternative which involves the acquisition of existing water rights will only be pursued with
willing owners.
Flow Recommendations and Supplemental
Flow Requirements for the Reach
The FWS recommended that "A flow "window" of 700 - 1,200 ft3/sec during July, August
and September" is required to meet the objectives of the Recovery Program. "During the
relatively infrequent dry years (one in five years) when this flow recommendation will be
more difficult to meet, 600 fe/sec is considered an adequate lower limit for this flow
window.' Based upon table 3 in the FWS report, it is necessary to deliver an additional
47,102 AF to the Reach during this three month period to ensure that, these minimum flows
would be achieved on an average of four out of five years. This means that if 47,102 AF
were delivered to the Reach every year then the desired flow would be achieved on the
average of four out of five years. Based upon historical flows, this 47,102 AF can be
viewed as a shortage for the Reach.
' U.S. Department of the Interior. Fish and Wildlife Service. Colorado River Fishery Project.
BIOLOGICAL DEFENSIBLE FLOW RECOMMENDATIONS FOR THE MAINTENANCE AND
ENHANCEMENT OF COLORADO .SOUAWFISH HABITAT IN THE `15-MILE' REACH OF THE UPPER
COLORADO RIVER DURING JULY, AUGUST, AND SEPTEMBER. May 1989.
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