Kinzua Dam is 1,897 feet long and 179 feet high, with 3,000,000 cubic yards of earthfill, 500,000 cubic yards of concrete, 19-foot-diameter penstocks through the dam, and a spillway 204 feet long with water depth of 18 to 20 feet. Authorized by the Flood Control Acts of 1936, 1938, and 1941, it was built by the US Army Corp of Engineers beginning in 1960 and completed in 1965. Its main purpose is flood control on the Allegheny and Ohio rivers, and it controls drainage on a watershed of 2,180 square miles, an area twice the size of Rhode Island. Additional benefits include drought control, hydroelectric power production, and recreation. Construction cost approximately $108 million. In 1972, when Tropical Storm Agnes brought continual heavy rains to the watershed and pushed the reservoir to within three feet of maximum storage capacity, more than $247 million in downstream damages were prevented.