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<br />iGSl <br /> <br />WATER QUALITY FOR RECREATION <br /> <br />Previous Studies and Activities <br /> <br />The Final Environmental Statement (FES) for the Narrows Unit evaluated <br />the water quality of the proposed reservoir. Existing bacteriological <br />data were obtained from the Colorado Division of Parks and Outdoor <br />Recreation and from the STORET data retrieval system maintained by the , <br />Environmental Protection Agency. These data were evaluated against <br />the Colorado Water Quality Standards for primary contact recreational <br />waters. On the basis of the available data, the reservoir appeared <br />to be suitable for such recreational activities. <br /> <br />A further analysis was made-of, the eutrophication potential of the <br />reservoir. Since nutrient concentrations in the river were known to <br />be quite high, it was thought that the reservoir could be excessively <br />productive. This was evaluated on the basis of existing nutrient <br />data and a comparison with Sutherland Reservoir in southwestern <br />Nebraska. This evaluation indicated that nutrients would probably <br />never limit either primary production or the standing crop of algae <br />in the reservoir. On the basis of algal productivity and standing <br />crop, the reservoir would be highly productive and would probably <br />be classified as eutrophic. However, the comparison with Sutherland <br />Reservoir, in which nutrients are not limiting and algal productivity <br />and biomass are quite high, indicated that there should be no problems <br />resulting from the high degree of productivity of the Narrows Reservoir. <br />Eutrophication can have any number of adverse side effects, including <br />those associated with aesthetics, oxygen deficits, and fishkills. <br />Sutherland Reservoir has experienced none of these. <br /> <br />The' FES also evaluated the potential for excess growths of rooted <br />aquatics, along with the potential for management of a coldwater <br />tailwater fishery. It was concluded that the potential for excessive <br />growth of rooted aquatic vegetation was low, except in the shallow <br />upper end of the reservoir; this conclusion was based on the degree of <br />annual water surface fluctuation in the reservoir. The coldwater <br />tailwater fishery was projected to be feasible only on a put-and-take <br />basis, due to warmwater releases during the summer. <br /> <br />16 <br />