Dams on the Rio Grande include Rio Grande Dam, Cochiti Dam, Elephant Butte Dam, Caballo Dam, Amistad Dam, Falcon Dam, Anzalduas Dam, and Retamal Dam. In southern New Mexico and the upper portion of the Texas border segment, the river's discharge dwindles. Diversions, mainly for agricultural irrigation, have increased the natural decrease in flow such that by the time the river reaches Presidio, little or no water is left. Below Presidio, the Rio Conchos restores the flow of water. Near Presidio, the river's discharge is frequently zero. Its average discharge is , down from at Elephant Butte Dam. Supplemented by other tributaries, the Rio Grande's discharge increases to its maximum annual average of near Rio Grande City. Large diversions for irrigation below Rio Grande City reduce the river's average flow to at Brownsville and Matamoros.