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<br />inundated periphery of the backwater with possible leaching of nutrients from <br />the inundated zone. Water level fluctuations in backwaters that resuspend <br />organic material increase turbidity which may provide cover for the native <br />fish that evolved in this ecosystem, and reduce the likelihood of predation on <br />Colorado squawfish by nonnative fish. Decreasing water levels in backwaters <br />resulting from reduced riverflows may result in export of nutrients and biota <br />to the river. The extent of export of nutrients and biota to the river cannot <br />be addressed at this time. <br /> <br />Concentrations of major nutrients (nitrate-N, ammonia-N, and phosphorus) <br />generally increased in backwaters from upstream at Island Park to downstream <br />at Ouray. Seasonal average TIN (N03-N + NOz-N + NH3) concentrations in the <br />river were greater than in backwaters at Island Park and Jensen, but greater <br />in Ouray backwaters than in the river there. Seasonal average TP <br />concentrations were lower in Island Park backwaters than in the river there, <br />but greater than in the river at Jensen and Ouray backwaters. Ouray backwater <br />nutrient concentrations exceeded river concentrations. Higher nutrient <br />concentrations in Ouray backwaters compared to Island Park and Jensen <br />backwaters and the river at Ouray may indicate internal nutrient recycling <br />within these backwaters or a response to attenuated riverflows compared to <br />upstream wherein nutrients transported into the backwaters from the river <br />during rising water levels are retained as riverflow decreases, or leached <br />from the inundated backwater shoreline. The less severe action of inundation <br />and draining in Ouray backwaters caused by attenuated riverflows may reduce <br />the tendency for violent mixing of water in backwaters, and reduce export of <br />POM and nutrients during draining. <br /> <br />5 <br />