OCR Text |
Show population of " trash" fish ( Utah chub). The Bureau of Sport Fisheries and Wildlife has estimated that Starvation Reservoir would have 26,500 man- days of fishing based upon an original design of 2,760 water surface acres. Under full operation of the proposed Bonneville Unit, the reservoir would exhibit a wide range of fluctuation-- depending upon the amount of available natural inflows. As a result the water level would be drawn down a little during years of high runoff but could be lowered to minimum pool level, a drawdown of about 100 feet, during drought years. Until completion and operation of the Strawberry Aqueduct would occur, Starvation Reservoir would remain relatively stable. Under the present plan of operation, the reservoir fluctuation is not severe and shoreline and aquatic ecosystems are not substantially disrupted by the changes in water level. Under proposed conditions, fluctuations would be greater and the existing stability would be reduced. Vegetative development would be curtailed and the utilization of shoreline habitats by birds and animals would be restricted. During periods of substantial drawdown, the productivity of the fishery would be reduced as the food producing areas would be above water. Operation studies show that drawdowns near the minimum pool level could occur about 10 out of every 40 years. - 30 The 3,000 acres inundated by the reservoir were good winter range for dser and were important to the deer population of the Uinta Basin. The deer formerly utilizing this range have been forced onto adjacent habitat. Some mitigation has been provided and is discussed in Section D. Starvation Reservoir also forms a partial barrier across deer migration routes to additional winter range. Inundation has also eliminated about 800 acres of pheasant habitat. However, fish and wildlife biologists indicate that there should be a slight improvement in existing pheasant habitat on about 26,000 acres of lands being irrigated with Unit water. Stream flow reductions have reduced fur- animal habitat but these adverse effects are not significant and are of minor economic value. Some waterfowl losses are occuring along the Duchesne and Strawberry Rivers because of the reduced flows. Several hundred acres of marsh habitat were also inundated. The reduction of flow below Knight Diversion Dam has its greatest adverse impacts upon wildlife during spring and early summer when waterfowl breeding and nesting occurs. The increase in irrigation flows improved habitat on some land during part of the fall migration period. There has also been a corresponding increase in habitat on the lower Duchesne River. Mitigation for waterfowl and pheasant losses is discussed in Section D. 214 |