OCR Text |
Show Material from the upper portal would be deposited below the waterline in Upper Stillwater Reservoir basin. Material from the lower portion of the tunnel would be disposed of in a draw near the outlet portal. Disposal piles would be terraced, contoured, seeded, and provided with drains to handle natural cross drainage. The disposal area should not be visible from the public road up the canyon. Tunneling entirely or primarily from the inlet portal is a viable alternative which would simplify the tunnel waste disposal problems. As described in paragraph A6b( 3), a $ 5 million research program is planned in connection with construction of Stillwater Tunnel. Several methods of tunnel waste removal and disposal would be tested-- some from each end of the tunnel. An access road has already been constructed to the Stillwater Tunnel outlet. This road traverses a steep canyon wall and despite careful construction creates a visual scar on the natural landscape. In addition, the road is causing some soil erosion. Re- vegetation attempts have not been completed and additional work will be done. The Bureau's research program, referenced above and discussed in Section A of this Statement, would include the investigation of enhancement methods. The construction of the North Fork Siphon is expected to cause long- term interference with existing plant and animal life. The site would be very difficult to restore because of the steep side slopes and thin soil mantle. Under the existing plan, which is under review and would be altered to a more esthetically satisfactory plan if feasible, it is estimated that the required clearing and construction activities would leave a visible scar about 100 feet or more in average width for approximately 1 mile along the siphon centerline. In addition to the scar there could be accelerated surface erosion and problems with soil sluffing on the canyon walls. This disturbance would eliminate an estimated 15- 20 acres of varied wildlife habitat and livestock forage. The burial, of the siphon across the North Fork River would create short- term stream turbidity and some longer term visual impacts where the stream banks would be disturbed by construction activities. Disposal of waste material from siphon excavation would leave a mound to be revegetated. The siphon crossing and access roads in the vicinity and crossing the North Fork River would disrupt the existing Castle Cliffs Campground. 235 |