Authorization: Flood Control Act, Public Law 81-516a, approved 17 May 1950; Project Document HD 442, 80th Congress, 2d Session.
Location: On the Grand (Neosho) River at river mile 449.9, 1.5 miles northwest of Council Grove in Morris County, Kansas; 47 miles southwest of Topeka and 75 miles northeast of Wichita.
Status: Complete.
Purpose: Flood control, water supply, water quality control, and recreation.
*Council Grove Lake works to accomplish these goals in conjunction with five other lakes that share a common watershed (the Grand/Neosho): Marion and John Redmond Reservoirs in Kansas, and Grand, Hudson, and Fort Gibson Lakes in Oklahoma.
History of Construction: Construction of the project began in June 1960. The project was placed in full flood control operation on 9 October 1964. Type of Structure: The rolled earthfill embankment is 6,500 feet long and rises 96 feet above the streambed. A roadway crosses the embankment and spillway.
Spillway and Outlet Works: The emergency, uncontrolled spillway is a 500-foot- wide open cut located in a saddle near the right abutment. Spillway capacity at maximum pool (elevation 1316.0) is 49,400 cfs. One 24-inch-diameter low-flow outlet (discharge capacity of 47 cfs at pool elevation 1240.0) and a 17-foot-diameter outlet conduit are located through the embankment near the right abutment. Outlet capacity is 8,900 cfs at pool elevation 1265.0 and 11,400 cfs at the top of the flood control pool (elevation 1289.0). Channel capacity below the dam site is 3,100 cfs. One 24-inch-diameter pipe for future water supply is provided in the structure.
Hydrologic Data: The flood of record occurred in June and July 1951 with a peak discharge of 121,000 cfs and a volume of 184,200 acre-feet, which is equivalent to 14.04 inches of runoff from the drainage area above the dam site.
Built by the Tulsa District of the U.S. Army Corps of Engineers at a cost of $11.5 million. Council Grove Lake is credited with preventing an estimated $175 million in flood damages as of 2012 .
Pertinent Lake Data:
Watershed . . . . . . . . . . . . . . . . . . 245 square miles
Shoreline . . . . . . . . . . . . . . . . . . . . 40 miles
Surface acres
Conservation pool . . . . . . . . 3,235 acres
Flood pool . . . . . . . . . . . . . . 5,400 acres
Elevation
Conservation pool. . . . . . . 1,274 ngvd
Flood pool . . . . . . . . . . . . . 1,289 ngvd
Capacity
Conservation pool . . . . . . . . 48,500 acre-feet
Flood pool . . . . . . . . . . . . . 112,265 acre-feet
Dam
Length . . . . . . . . . . . . . . . . . 6,500 feet
Height above streambed . . 96 feet
Outlet Works
1 outlet conduit. . . . . . . . . . 17 feet in diameter
1 low flow pipe . . . . . . . . . . 2 feet in diameter
1 water supply pipe . . . . . . . 2 feet in diameter
1 uncontrolled spillway . . . . 500 feet in width