OCR Text |
Show existing Strawberry Tunnel and natural stream channels for conveyance. The Strawberry Tunnel was constructed between the years 1906 and 1912 as part of the Strawberry Valley Project. The 3.8- mile- long tunnel is concrete lined and has a freeflow capacity of 600 c. f. s. Sections of the tunnel have seriously deteriorated since its construction. Strawberry Project water and the natural flow from the outlet portal of the tunnel to Spanish Fork River have also caused extensive erosion to the natural creek channels, especially the Sixth Water Creek channel. Under this alternative, rehabilitation of the tunnel and the channelizing of at least 10 miles of the stream channel would be mandatory. All methods of lining the existing tunnel would reduce its capacity. If the tunnel were relined, either additional excavation of the tunnel or raising the level of Strawberry Reservoir by increasing the size of the new Soldier Creek Dam would be needed to maintain the tunnel's present capacity. Tunnel excavation and lining could only be accomplished during the nonirrigation season and would therefore be expensive and take several years to complete. If the reservoir level were raised to increase the head on the tunnel, several hundred additional acres of grazing land would be inundated. One alternative for conveying Bonneville Unit water would be in a separate Fifth Water Tunnel. About k. 6 miles of new tunnel would be needed, and 7 miles of the Fifth Water channel would require extensive channelization and riprapping, if no power production were included in the plan. If power production were included, three powerplants would be constructed, with a peaking capacity of 132,000 kilowatts. Two reservoirs, with a total storage capacity of 3,500 acre- feet would also be included. One reservoir would provide fishing, with a. dead storage capacity of 2,000 acre- feet and an active storage capacity of 500 acre- feet. The other reservoir would not provide fishing. The 7 miles of channelization would not be needed because of replacement with a mile of penstock, 1 1/ 2 miles of tunnel, 2 1/ 2 miles of pipeline, and 2 miles of reservoir. Another alternative plan would convey Strawberry Project and Bonneville Unit water by tunnel to a point just above Syar Powerplant. A daily regulating reservoir would be installed just below the powerplant. It would have an active capacity of 550 acre- feet and would not provide fishing. From the reservoir, the water would travel 599 |