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<br />0MB <br /> <br />Old Charlie Wash <br /> <br />Old Charlie Wash is a floodplain depression that has been <br />restored for testing hypotheses on floodplain habitat and <br />razorback restoration. It has inlet and outlet water control <br />structures, fish screens to allow access of small fishes but <br />prevent access by larger fishes, and a collection kettle for <br />the efficient harvesting of fishes. <br /> <br />Old Charlie will be dry prior to 1996 spring runoff. During <br />runoff, water will be allowed to fill Old Charlie through the <br />inlet and outlet water control structures. Water will be held <br />at the site only during runoff. Immediately after runoff, when <br />the site becomes disconnected from the main channel of the <br />river, the site will be allowed to drain, and all fish will be <br />harvested. Water will not be held for an artificially extended <br />duration. If 1996 is a low to moderate flow year, fish screens <br />will be tested to see if they prevent all but the smallest <br />fishes from getting into the site. If 1996 is a high flow <br />year, the river will overtop the banks, allowing fish of all <br />types and sizes into Old Charlie. Following are hypotheses to <br />be tested during FY 96: <br /> <br />2/22/96 <br /> <br />-Floodplain depressions connected to the main channel of the <br />river will provide suitable nursery and/or grow-out habitat for <br />young razorbacks, and habitat for adult razorbacks. <br />-Fish inlet/outlet control screens will prevent access by <br />fishes greater that three inches in length, but allow access by <br />larvae. <br />-Production (plankton, benthos) is sufficient to sustain <br />razorback larvae over time. <br />-Physical, chemical, and biological conditions are favorable <br />for sustaining razorback larvae. <br />-Old Charlie can be managed in a way that prevents exacerbation <br />of Green River nonnative fish problems. <br />-Allowing Old Charlie to fill and drain naturally during spring <br />runoff will prevent build-up of nonnative fishes. <br />-Fish species/life stages are equally vulnerable to all gear <br />types/sampling strategies <br /> <br />Gravel Pit at 29 5/8 Road <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 is being connected to the river to <br />determine if gravel pits can act as a surrogate floodplain <br />habitat to assist in recovery of the endangered fishes. Post- <br />restoration evaluation will determine adequacy of site <br />conditions for sustaining endangered fishes; composition and <br />relative abundance of fish species using the site; and <br />nonnative fish management strategies. Following are hypotheses <br />to be tested: <br /> <br />13 <br />