Loma Alta Lake is located about eight miles northeast of Brownsville in Cameron County, an off-channel reservoir from the Rio Grande. The reservoir is owned and operated by the Brownsville Navigation District for municipal and industrial water supply, and recreational purposes.
Authorization (Permit No. 1838) was issued by the State Water Board of Engineers on November 10, 1958 and was completed in March 1963. The dam is an earthfill embankment with variable height and cross section. The average bottom width is about 90 feet and the top width is about 18 feet, with top elevation at 21.5 feet above mean sea level. The reservoir has a capacity of 26,500 acre-feet encompassing a surface area of 2,490 acres at the conservation pool elevation of 17.5 feet above mean sea level. Water level is maintained by pumping from the Rio Grande during off-season irrigation demands.