OCR Text |
Show Rock Creek, below Upper Stillwater Damsite, is rated as Class II- a fishery of Statewide importance. Recommended minimum flows designed to prevent substantial loss to natural fisheries, of 20 * and 25 c. f. s. have been determined as essential. The existing Unit plan partially accommodates these recommendations and a 25 c. f. s. minimum flow would be maintained at the Forest- Indian Reservation boundary. Between the proposed damsite and the Indian Reservation boundary, flows during the critical winter period would range from a minimum of 5 c. f. s. ( 8 c. f. s, is the average of a 5- to 11- c. f. s. range estimated release) at the dam and gradually increase to 25 c. f. s. in the 8- mile reach through the National Forest. This means that of approximately 23 miles of stream below Upper Stillwater Dam that would receive reduced flows, the flow in about 16 miles of Class III stream would exceed the recommended minimum and much of the existing fish habitat would be preserved. South Fork of Rock Creek Docs Diversion Structure, an appurtenance of Strawberry Aqueduct, would intercept South Fork of Rock Creek 1.3 miles above the confluence with Rock Creek, and 0.7 mile above U0S0G0S# Gaging Station No. 9- 2780. Flows up to the 100 c. f. s. capacity of the inlet structure would be diverted to Upper Stillwater Reservoir except for a 1.5 c. f. s. intermittent bypass during the summer months for downstream electrical power rights. The October to March winter flows at the diversion point would be expected to be in the 3- to 8- c. f. s. range, although a minimum flow of 1.5 c. f. s. was recorded during March 1963. The total annual amount of water that would be diverted is estimated at 9,000 acre- feet with only 100 acre- feet of spills and minor bypasses « , The near total diversion from this tributary would be expected to destroy most of the existing aquatic habitat in this 1.3- mile section of Class III trout fishery. Hades Creek Strawberry Aqueduct would intercept Hades Creek at a point 3,000 feet above the confluence with 306 |