OCR Text |
Show ( 6) Utah Lake Diking Provo and Goshen Bays would be separated from the main body of Utah Lake by dikes to reduce evaporation losses. The proposed Provo Bay Dike would separate the eastern extremity from the lake. It would be an earthfill structure, with a maximum height of 2k feet above the bed of the lake. Goshen Bay Dike would separate the southern bay from the lake and would prevent saline water accumulating in the bay from entering the lake. This dike would be a terraced earthfill structure which would allow for settlement in the foundation. It would have a maximum height of about 30 feet. Artist's concepts of Provo Bay and Goshen Bay Dikes are shown in Figures A- 31 and A- 32. The drawdown of the diked Utah Lake would be similar to that which has occurred historically. Seasonal fluctuations should be in the 2- to 5- foot range. In drought years the lake could be drawn down to 12 feet below compromise level; however, attempts would be made to limit demands and drawdown to 9* 3 feet below compromise level. Ample fine- grained materials suitable for construction of Provo Bay Dike are available at the site. Coarse- grained, gravelly materials are in ample supply along the foothills between Provo and Springville. Limestone and quartzite outcrops suitable for riprap are found in the Wasatch Mountains to the east, in the Lake Mountains to the west, and on West Mountain. Although a specific quarry site has not been selected, the West Mountain site- which could be used for both dikes- would probably be the better site from an environmental standpoint. Concrete aggregate would be obtained from commercial sites nearby. Earth- embankment materials for construction of Goshen Bay Dike are available in ample quantities within 3 miles of either abutment. These borrow areas are not within the lake area and would require restoration measures. One area on the northwest end of the dike would require coordination with a potential recreation site. Limestone of suitable quality for riprap can be obtained from West Mountain or from the Lake Mountains, a haul distance of about 3 miles from either abutment. Further study would be required to select a specific quarry site. Concrete aggregate could be obtained by processing Lake Bonneville terrace deposits near either abutment or from nearby commercial suppliers. Figure A- 33 is a sketch map of Utah Lake showing proposed borrow and recreation areas. 97 |