Loyalhanna Lake, authorized by the Flood Control Acts of 1936 and 1938, is one of 16 flood damage reduction projects in the Pittsburgh District. An important link in a system of flood control projects, Loyalhanna provides flood protection for the lower Loyalhanna Creek and Kiskiminetas River valleys as well as the lower Allegheny and upper Ohio Rivers. Since its completion in 1951, the Loyalhanna project has prevented flood damage estimated to be in excess of $303 million. The project has the capability to store the equivalent run-off of 6.16 inches of precipitation from its 290 square mile watershed. When compared to the flood protection benefits, the construction cost of $5.5 million appears small.
Located on Loyalhanna Creek, 4.5 miles above its junction with the Conemaugh River at Saltsburg, Pa. forming the Kiskiminetas River. The lake and dam is located entirely in Westmoreland County, Pennsylvania.
Project Area: 3,722 acres
Drainage area above dam: 290 sq. mi.
Construction costs: $5,500,000
Type structure: Concrete gravity type with gate-controlled center spillway and adjoining earth embankment on left bank.
Volume of concrete and earth fill: 182,588 cu. yd.
Maximum height above streambed: 114 ft.
Total length: 960 ft.
Maximum width at base: 88.5 ft.
Four 5.67' x 7' gate-controlled sluices
One 24" value-controlled sluice
Five 29' x 30' crest gates
Length at summer pool: 4 mi.
Summer Area: 400 acres
Maximum Area: 3,280 acres
Streambed at Dam: 869 ft.
Maximum Pool: 975 ft.
Summer Pool: 922 ft.