151. Looking upstream from station 9+72 showing the upstream 310 152. View of inlet to inclined shaft showing the steel in place at 313 153. View of power tunnel taken from station 2+75, elevation 5445 313 154. Outlet tunnel intake structure andesite rock foundation 315 155. Looking upstream at the outlet of the power and outlet tunnels 316 158. View looking upstream from station 18+50 of the outlet tunnel, 325 168. View of outlet manifold wye W1 rupture, looking downstream 368 182. Power and outlet tunnel liners, station 10+12 to station 17+48 407 183. General view of operating bridge in spillway inlet structure, 412 PART I--INTRODUCTION CHAPTER I--HISTORY AND DESCRIPTION 1. Location - Palisades Reservior (fig. 1) is located on the South Fork of the Snake River in Idaho, near the Idaho-Wyoming border. The dam is located in section 17, T. 1 S., R. 45 E. of the Boise Meridian, Bonneville County. The site is within the Caribou National Forest approximately 7-1/2 miles upstream (southeast) from Irwin, Idaho, on Idaho State Highway No. 29 (U. S. Highway No. 26). A small portion of the reservoir extends into Wyoming. 2. Purpose of Project. The purpose of the Palisades project is to conserve the runoff of winter water and thus provide: (1) Supplementary irrigation water for approximately 650, 000 acres of arable land in the upper Snake River Valley. (2) Flood protection for several thousand acres of irrigated land on the flood plain of the Snake River above Idaho Falls, Idaho. (3) Hydroelectric power for rural electrification including irrigation pumping, municipalities, and other power requirements. (4) Conservation of fish and wildlife. (5) Recreational areas. 3. Development of the Project Prior to 1952. - The Bureau of Reclamation in 1932 initiated surveys of 27 reservoir sites on the upper Snake River. Thirteen of these sites were found to be geologically unsuited for the construction of reservoirs. Many of the remaining sites were found to be unsuitable for holdover reservoirs of large capacity because of the excessive height of dams required or possible reservoir leakage. At a meeting of Snake River interests at Idaho Falls, Idaho, on July 10, 1939, the "Grand Valley" reservoir site was selected as the most attractive possibility for storage development and the Bureau of Reclamation was urged to proceed with the construction of the reservoir. The following considerations influenced the selection of this site: (1) Active storage for 1,400,000 acre -feet with lowest dam. (2) Adequate dam foundation. (3) Satisfactory foundations for spillway, outlet works, and power system. (4) Rock abutment through which tunnels could be bored. (5) Space for reservoir without destroying large areas of valuable agricultural lands. (6) Major portion of reservoir in Idaho. A detailed investigation of the Grand Valley site was made by the Bureau of Reclamation and a report was issued in 1940. This report was summarized in House Document No. 457, 77th Congress, 1st Session. This document formed the basis for authorization of the project. Construction of the dam, however, was made contingent upon elimination of wasteful water-use practices. This 1940 report also stated that the success of the project would depend on the conservation of 135,000 acre-feet of water annually being wastefully used as a result of winter diversions, and also on the willingness of the water users to pay for stored water that would be available from the project. It was found desirable to change the name of the reservoir and the project in order to prevent confusion with the Grand Valley project in Colorado. In 1941, after conferences with Idaho interests, including the Congressional delegation, it was decided to change the name to Palisades Dam and Palisades project. |