| Foss Reservoir | |
| Location: | Custer County, Oklahoma |
| Coords: | 35.568°N -99.222°W |
| Type: | Reservoir |
| Inflow: | Washita River |
| Outflow: | Washita River |
| Catchment: | 1496sqmi |
| Basin Countries: | United States |
| Agency: | U.S. Bureau of Reclamation |
| Date-Built: | October 1958 |
| Date-Flooded: | October 1962 |
| Length: | 10.91miles |
| Width: | 2miles |
| Area: | 8800acres |
| Volume: | 256220acre.ft(flood capacity)[1] |
| Shore: | 63miles |
| Elevation: | 1652feet |
| Islands: | several islets |
| Cities: | Foss, Oklahoma; Clinton, Oklahoma |
| Pushpin Map: | Oklahoma#USA |
| Pushpin Map Alt: | Location of Foss Reservoir in Oklahoma, USA. |
Foss Reservoir, also known as Foss Lake, is in Custer County, Oklahoma on the Washita River, about 15miles west of Clinton, Oklahoma. The reservoir was constructed during 1958–1961 by the U. S. Bureau of Reclamation. The project was known originally as the Washita Basin Project. The lake and dam were named for the community of Foss, Oklahoma, about 6miles south of the site. Their primary purpose is to regulate flow of the river and to provide water for the cities of Bessie, Clinton, Cordell and Hobart.[2] It is western Oklahoma's largest lake[3] and lies entirely within Foss State Park.
The reservoir has a surface area of 8800acres and a shoreline of 63miles.[4] The capacity of the reservoir is 436812acre-feet.[5] The reservoir serves a catchment area of 1496sqmi. The reservoir has a mean depth of 23feet and a maximum depth of 89feet.[3]
Dam construction began in October, 1958. The dam is 142feet high, 38feet wide (at the crest) and 18130feet long.[3]
Foss State Park encompasses 1749acres of land and contains 8 campgrounds, swimming beach, 6 boat ramps, a playground, marina, and a restaurant. It also has 19miles of equestrian and multi-use trails.[3] Foss State Park is often mentioned as a target for sale or closure to help close the state's current budget deficit. Already the state has sold a herd of bison as "surplus property." The bison had recently been moved into Foss State Park from another location in western Oklahoma.[6]
The water quality in Lake Foss is extremely hard. The Bureau of Reclamation built one of the first electrodialysis plants in the United States to process the water before it is delivered to users. The Oklahoma Department of Environmental Quality constructed a new, updated plant to replace the original in 2002.[7] The new plant, built by Ionics, Inc., would also increase production of potable water for its municipal customers from 3 million to 4.5 million U.S. gallons per day.[8]
Water is transported from the dam to consumers via three pumping stations and 50.8miles of aqueducts.[9]