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, water supply, hydroelectric power, navigation, fish and wildlife. and recreation.
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. Construction of the auxiliary spillway was completed in January 2009.
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. It has a maximum height of 45 feet, and a design crest height of 676.7 feet.
Spillway and Outlet Works: The main spillway capacity is 290,400 cubic feet per second (cfs) at maximum pool (elevation 672.2) with flow controlled by ten 50- by 25-foot tainter gates. The auxiliary spillway capacity is 229,340 cfs at maximum pool with flow controlled by five 50- by 35-foot tainter gates. The crest of the main spillway is at elev. 642 and the auxiliary crest is located at elev. 632. 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.
Hydrologic Data: Estimated peak discharge and volume of the December 2015 flood were 149,200 cfs and 900,763 acre-feet, respectively. The record peak release was for this flood at 35,000 cfs. Total runoff from the drainage area above the site was 10.48 inches for the entire period. The March and April 1945 flood had more total runoff with lower peak flows at 1,184,000 acre-feet and 118,000 cfs, 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.