Eagle Mountain Reservoir, formerly Eagle Mountain Lake, is on the West Fork of the Trinity River just north of Lake Worth in northwestern Tarrant and southwestern Wise counties (at 32°53' N, 97°28' W). It is owned and operated by the Tarrant County Water Control and Improvement District No. 1 to supply water to Fort Worth for municipal and industrial uses and for irrigation and recreation. Construction of the dam began on January 23, 1930, and was completed October 24, 1932. Impoundment of water began on February 28, 1934. The dam is 85 feet high and 4,800 feet wide, with an original spillway width of 1,300 feet. The crest of the service spillway is at 649.1 feet above mean sea level. The reservoir has a normal capacity of 190,460 acre-feet and a maximum capacity of 680,335 acre-feet; its surface area at normal capacity is 9,200 acres and at maximum capacity, 19,050 acres. A new service spillway was added in 1971 at a cost of $2,565,679. The drainage area of the West Fork of the Trinity River at Eagle Mountain Dam is 1,970 square miles.