Black Lake Bayou Reservoir (22 sq mi/57 sq km), Natchitoches co., NW La., on Black Lake Bayou, 15 mi/24 km NNE of Natchitoches; 31°50'N 92°57'W. Max. capacity 320,000 acre-ft. Formed by Black Lake Bayou Dam (44 ft/13 m high), built (1990) for recreation.