OCR Text |
Show ) Environmental Impacts of the Alternative The impacts described here are primarily for those features in the Round Valley area. The impacts of the other features of this plan are the same as the respective feature impacts on the proposed plan. The open channel from Strawberry Reservoir minimum water surface level to the inlet of Wallsburg Tunnel would be about 3 miles long and would require extensive excavation parallel to a portion of U. S. Highway kO. The channel would be exposed periodically as the reservoir water surface fluctuated. About 2 miles of Strawberry River would be affected by both the increased reservoir water level and the excavation of the intake channel. Materials from the channel would be disposed of by spreading them in the reservoir basin in such a manner as to blend with the natural terrain. The excavation would be accomplished by sloping and rounding backslopes to minimize their effect on the natural area. Construction would cause sediment to enter Strawberry River and the reservoir unless preventive measures were taken. Materials excavated from Wallsburg Tunnel would be deposited in the area adjacent to Main Creek. Settling ponds would be required to reduce the sediment in Main Creek caused by construction activities. This excavated material would be shaped to conform with the natural area and then treated and seeded with natural vegetation. Construction activities would temporarily disrupt fauna in the upper end of Round Valley. Increased flows would be released into Main Creek for about 10.6 miles from Wallsburg Tunnel outlet to Deer Creek Reservoir. The year- round increased flow would reach a maximum of 260 c. f. s. during July of each year. The stream channel would be protected from increased erosion by riprap. Annual streamflows in the Provo River from Deer Creek Dam to Murdock Diversion Dam would be increased above those of the proposed plan. The impacts of using this water for municipal and industrial purposes in Salt Lake County would be about the same as the impacts from using Bonneville Unit water. However, with less water, fewer present and future needs would be met in Salt Lake County. Jordanelle Reservoir would not be constructed on the Provo River, upstream flooding of the Provo River would not be controlled, and the flood control benefits would not be made available to the project. Return flows from the municipal water supplies would be made available for industrial uses The return flows could also be made available to the bird refuges near the mouth of the Jordan River, and the outflow from them could be used to maintain a higher level in the Great Salt Lake than without this alternative. 570 |