OCR Text |
Show Expected beneficial impacts would be associated with the storage and regulation of Unit return flows and spills from Utah Lake, flood control provided to the lower Jordan River area, and enhancement of the local outdoor recreation potential. It is expected that the reservoir would help to assimilate the demand for recreation in the immediate area of Salt Lake City. The recreational aspects would be further evaluated and an environmental assessment made for proposed developments. Lampton Reservoir is presently included in plans for development of a parkway along this section of the Jordan River. This plan is discussed in Section A. Associated with construction of the dam would be the usual problems of adverse impacts on the landscape. Borrow areas for fill and riprap have not been located. Preliminary explorations suggest that the reservoir basin would not provide adequate sources of materials so there would be impacts on the environment connected with providing these items. ( 2) Utah Lake Dikes The proposed construction of the Provo and Goshen Bay Dikes would separate these bays from the main lake body and thus reduce the water surface area about 35 percent, from 95,900 acres to 61,100 acres at compromise leveLi/ ( See Figures A- 31 and A- 32.) This reduction in water surface area would reduce the annual evaporation losses from the lake about 105,000 acre- feet. This amount, together with Unit return flows and spills now lost from the system, would produce a net increase in yield of about 148,500 acre- feet annually. This water would then be exchanged for high quality water upstream on Provo River and stored in Jordanelle Reservoir for irrigation, municipal and industrial purposes, or used directly from the lake for irrigation. 1/ With a dam at its outlet Utah Lake sometimes rises above its normal surface elevation in years of high inflow, flooding adjacent lands. Until 1885 this resulted in conflicts between the land owners and lake water userse In that year the conflict was settled by an agreement which fixed the compromise level of the lake. The elevation of compromise level is 4,489.34 feet above sea level as related to adjusted datum of the United States Coast and Geodetic Survey. Whenever runoff forecasts during the filling season indicate that under controlled operation the lake level will exceed that elevation, the outlet gates are opened prior to and during the high runoff season to permit discharges comparable to natural outflow conditions. 244 |