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<br />I <br />I <br />I <br />I <br />1 <br />1 <br />1 <br />1 <br />I <br />I <br />I <br />I <br />I <br />1 <br />I <br />I <br />1 <br />I <br />I <br /> <br />VI. Division of Water Resources Administration <br /> <br />The State of Colorado Division 5 Water Resources 1999 Annual Report is not yet available. When it is <br />finalized, the report can be found on the State Engineer's Web Site at: http://water.state.co.us/default.htm <br /> <br />VII. Fish & Wildlife Service Monitoring <br /> <br />Recent biological and geomorphology studies have documented changes in physical processes <br />and native fish populations related to the modification of the natural snowmelt hydrograph due to <br />the construction of reservoirs upstream of the Colorado-Utah State line. These changes have <br />reduced the ability of the Colorado River to move sediment and rework the river channel (Pitlick <br />1999). It is generally accepted that these reservoirs have altered stream flows of the Colorado <br />River and have caused changes in the amount, diversity and quantity of habitat used by the <br />endangered Colorado River fish. <br /> <br />In compliance with the Recovery Program RIPRAP, monitoring of embeddedness of gravel and <br />cobble substrates in the upper Colorado River was initiated. Twelve measurements were taken at <br />each of 15 sites (eight in the 15-mile reach; seven in the 18-mile reach) on seven dates in 1996 <br />(three during runoff; four during baseflow) and five dates in 1997 (three during runoff, two <br />during baseflow). Rock sizes were generally larger lower in the channel at base flow elevations <br />than higher in the channel margin inundated during runoff. <br /> <br />Additionally, average rock size was slightly larger in the 18-mile reach than in the IS-mile reach, <br />but only at base flow locations. Spring runoff flows in both the 15- and 18-mile reaches were <br />sufficient in both years to mobilize the bed in many areas. In addition, runoff flows during 1995 <br />(prior to sampling) produced widespread mobilization of the bed. Average rock sizes changed <br />significantly between 1996 and 1997 at several of the sampling sites. Mean depth to <br />embeddedness (distance from the top of rocks in the surface layer down to the point where rocks <br />are embedded in fine sediment) ranged from 80 to 171 mrn; the adjusted mean of the samples <br />was 125 mm in 1996 and 123 mrn in 1997. The mean number of 'free rocks' (those making up <br />the layer above the level of embeddedness) ranged from 1.1 to 4.3; the adjusted mean was 1.9 <br />rocks in both years. <br /> <br />Riffles had slightly greater depths to embeddedness than did runs. For other comparisons, depths <br />to embeddedness were found to be similar between thel5- and 18- mile reaches, between 1996 <br />and 1997, and between runoff and base flow periods. Rates of sedimentation were low during <br />summer and fall following runoff and depth to-embeddedness remained fairly constant through <br />the base flow period. The two years of initial sampling represents a period of time when both <br />reaches were freshly cleaned of fine sediment and the data should provide a good baseline for <br />future monitoring. In addition, the USFWS also conducted its Standardized Monitoring <br />Program <br /> <br />Benefits of coordinated operations are discussed in the standardized monitoring efforts. In <br />addition, on February 13, 1999, the FWS provided a report on releases from Ruedi Reservoir, <br />which included discussion of the benefits of peak flows. <br /> <br />]2 <br />