The Ogallala Formation of Tertiary (Pliocene) age is the principal aquifer in the Southern High Plains of western Texas and eastern New Mexico. This heavily pumped aquifer supplies practically all the water used for irrigation, municipal, industrial (except oil-field repressuring), and domestic purposes.
Although the ground water in the Ogallala Formation in the Southern High Plains is common to both Texas and New Mexico, the State laws concerning ownership of the water are different. The New Mexico statutes provide that all underground waters of the State belong to the public and are subject to appropriation for beneficial use (Reynolds, 1961, p. 79). Under conditions specified in the law, the State Engineer may declare certain areas as underground water basins in which the State Engineer has jurisdiction over the drilling of wells. The approximate boundaries of two such basins in New Mexico are shown on the maps. In Texas, the landowner owns the underground water. Under a law passed by the Texas State Legislature in 1949, underground water conservation districts may be formed with the authority to make rules and regulations for the conservation of ground waters, such as rules governing the minimum spacing of wells, and rules for the prevention of waste and contamination of fresh water, and other practices for the conservation of ground water. The approximate boundaries of two underground water conservation districts in Texas are shown on the maps.
