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<br />'~Me <br /> <br />Old Charley will be used for nonnative fish removal in 1998, <br />During runoff, the Old Charley outlet will be open to allow <br />fish access, As runoff begins to subside. the outlet gate will <br />be closed to trap the fishes. When flows drop below 3.000 cfs <br />,(-July), the site will be drained and all fishes harvested, <br /> <br />Gravel Pits (29 5/8 Road Gardner Pond and Jarvis Site) <br /> <br />There are -340+ gravel pits in the Grand Valley area of the <br />Colorado River and the Delta area of the Gunnison River, The <br />Gravel Pit at 29 5/8 Road was connected to the Colorado River <br />in December 1995, to determine if gravel pits can act as a <br />surrogate floodplain habitats to assist in recovery of the <br />endangered fishes, The site has been used by a number of <br />squawfish, and numerous nonnatives (Burdick et al, In prep), <br /> <br />During FY 98, the site will be filled and graded to allow <br />seasonal use by fishes but prevent year-round use and bUild-up <br />of nonnatives, The Jarvis site. another old gravel pit, will <br />also be configured for seasonal use, Both sites will be <br />monitored during FY 98, to evaluate use by endangered and <br />native fishes. and to evaluate nonnative fish control <br />techniques (Pfeifer and Burdick FY 98 SOW attached), <br /> <br />Walter Walker <br /> <br />Selenium concentrations in the Gunnison River and in the <br />Colorado River below the Gunnison exceed levels of concern, <br />Walter Walker is a large floodplain depression along the <br />Colorado River (RM 164) that has been used extensively by <br />Colorado squawfish and razorback suckers. Levels of selenium <br />measured in water samples from Walter Walker ranged <1 to 170 <br />ppb (level of concern is 2 to 5 ppb); levels in dry weight <br />whole-body fish samples ranged 74 to 137 ppm (level of concern <br />is 8 ppm) , Walter Walker, combined with Adobe Creek and <br />Horsethief, have been used to determine if,razorback suckers <br />are adversely affected by high levels of selenium in floodplain <br />sites (Hamilton et al, In prep) and. if so, if "freshening <br />flows" can be used to reduce selenium levels, During FY 98. <br />selenium remediation techniques will be tested at Walter <br />Walker. to determine if selenium concentrations can be reduced <br />to "acceptable" levels via flushing (Holley, Hamilton. and Buhl <br />FY 98 SOW attached). <br /> <br />19 <br />