Authorization: Flood Control Act approved June 28, 1938. Installation of power features was authorized by the River and Harbor Act approved July 24, 1946; Project Document Committee No. 1, 75th congress, 1st Session, HD 758, 79th Congress, 2d Session.
Location: On the Illinois River at river miles 12.8, in Cherokee and Sequoyah counties, about 7 miles northeast of Gore and about 22 miles southeast of Muskogee, Oklahoma.
Purpose: Flood control and hydroelectric power.
History of Construction: Major construction started in June 1947. The spillway, outlet works, and tunnels were completed in 1951, and embankment closure occurred in May 1952. Impoundment of the power pool began in July 1952. The project was completed for full flood control operation in July 1953. Installation of the two hydropower units was completed in December 1953, and power generation was initiated. Work on the repair and extension of the spillway apron was initiated in July 1960 and completed in August 1961. In fiscal year 2003, Phase 1 of a dam safety project was begun at the lake. Phase 2 began in fiscal year 2004 and was completed in fiscal year 2006. The dam safety project consists of an auxiliary spillway with five 50-foot wide by 35-foot high tainter gates constructed near the right abutment of the embankment. The spillway structure is similar to the existing spillway. In addition, a new Highway 100 bridge was built to carry traffic across the upstream approach channel for the new spillway. On November 29, 2006, a ribbon cutting ceremony was held marking the completion of the spillway project.
Type of Structure: The structure is a rolled, impervious and semi-pervious earth-filled dam about 3,000 feet long with a maximum height of 197 feet above the streambed. Oklahoma State Highway 100 extends across the top of the dam. An earth-filled dike about 1,350 feet long is located between the right end of the dam and the spillway.
Spillway and Outlet Works: The concrete, gravity spillway, located in a narrow ridge comprising the right abutment of the dam about 800 feet west of the axis of the dam, has a total width of 590 feet. Spillway capacity is 290,400 cfs at maximum pool (elevation 672.2) with flow controlled by ten 50-by 25-foot tainter gates. A flood control outlet extending through the narrow ridge comprising the right abutment consists of a 19-foot conduit. Capacity of the conduit is 23,300 cfs at the top of the flood control pool. Flow through the conduit is controlled by two 9- by 19-foot tractor-type service gates installed at the upstream end of the conduit and operated by individual electric hoists located on the operating floor of the gate tower structure. A 19-foot-diameter penstock is provided through the narrow ridge comprising the right abutment to the powerhouse. Operational channel capacity below the dam is 10,800 cfs.
Hydrologic Data: Estimated peak discharge and volume of the March and April 1945 floods were 118,000 cfs and 1,184,000 acre-feet, respectively. Total runoff from the drainage area above the site was 13.79 inches for the entire period. The May 1950 flood had a peak discharge of 180,000 cfs with a volume of 720,000 acre-feet, which is equal to 8.39 inches of runoff.