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<br />.. <br /> <br />STATE OF COLORADO <br />Roy Romer, Goyernor <br />DEPARTMENT OF NATURAL RESOURCES <br /> <br />DIVISION OF WI LOll FE <br /> <br />AN EQUAL OPPORTUNITY EMPLOYER <br /> <br />Perry O. Olson. Director <br />6060 Broadway <br />Denyer, Colorado 80216 <br />ToI",,""o8: (303) 297-1192 <br /> <br />REFER TO <br /> <br />CWe8 <br />iiOV 12 1931 <br /> <br /> <br />MEMORANDUM <br /> <br />TO: Members, CWCB <br /> <br />FROM: Perry Olson, Director, <br /> <br /> <br />DATE: November 9, 1991 <br /> <br />SUBJECT: Agenda Item 13-b-2, November 14-15, 1991, Board Meeting <br />Endangered Fish, Recovery Program <br />Instream Flow Recommendations for the 15-Mile Reach for <br />October-June <br /> <br />INTRODUCTION <br /> <br />In April, 1991, the U.S. Fish and wildlife Service published <br />Recommendations for Flows in the 15-Mile Reach During October-June <br />for the Maintenance and Enhancement of the Endangered Fish <br />Populations in the Upper Colorado River (Osmundson and Kaeding, <br />1991). This report along with a previously published document <br />recommended year-round flows for the 15-mile reach of the Colorado <br />River. Division of Wildiife staff has reviewed the final report and <br />now provides the Board with its opinions and recommendations. <br /> <br />Summarv of ReDort <br /> <br />Service researchers first lay the foundation for their <br />recommendations by citing studies which show that Colorado <br />squawfish and razorback suckers utilize the 15-mile reach--adult <br />squawfish are found there throughout the year and razorback suckers <br />congregate in this reach during their spawning season (April-June). <br />They then illustrate the importance of flows to the fishes'. <br />habitat, including channel morphology, water quality and <br />temperature, food production, predation, and competition. Flows in <br />the Colorado River have been altered by both the in-basin water <br />projects and the transmountain diversion projects that were <br />developed in the mid 1900's (see Figure 1). It is thought that <br />this change in the river's hydrologic regime may be a contributing <br />factor in the decline of the native fish. The management of <br />instream flows may benefit the native fishes concurrent with <br />control of the abundance of introduced non-native fishes that <br />compete with or prey on the native fishes. <br /> <br />Methodoloqy <br /> <br />The methodology used in developing these flow recommendations <br />differs from the techniques used to develop the summer flow <br />recommendations, accepted by the Board in January of 1990. <br /> <br />DEPARTMENT OF NATURAL RESOURCES. Kenneth Salazar. ExecutIVe Director <br />WILDLIFE COMMISSION. William R. Hegberg. Member. Eldon W. Cooper. Chairman. Felix Chavez. Member. Rebecca L Frank. Member <br />Louis F. Swift. Member. George VanDenBerg. Member. Larry M. Wright, Member. Thomas M. Eve. Membar <br />