PROBLEMS FROM DEVELOPMENT 153 



the area and density of water-loving vegetation have in- 

 creased, and salt cedar (one of the worst of water wastrels) 

 has infested progressively increasing areas near the river 

 above San Marcial. The consumptive waste by vegetation 

 is considered to be largely responsible for New Mexico's 

 inability to meet the terms of its compact with Texas in the 

 past eight years. 



In 1948 about 15,000 acre-feet of water was pumped for 

 municipal, irrigation, and industrial use. Records show that 

 there has been little lowering of Avater levels, and pumping 

 has probably not reduced significantly the flood-plain evapo- 

 transpiration losses. Unless the pumped water is salvaged 

 from that waste, it is inevitable that the flow of the river 

 must be depleted. 



In the Elephant Butte district below the Middle Rio 

 Grande Valley, pumping from irrigation wells began in 

 1948. The conclusions of a study recently completed are: 

 "The ground-Avater and surface-water supplies are inter- 

 dependent, and ground water pumped in the Rincon and 

 Mesilla Valleys does not represent an additional supply or 

 new source of water but rather a change in method, time, 

 and place of diversion of the supplies already utilized." 76 



The Nebraska Supreme Court has construed the state water 

 code as restricting the use of water to lands within the water- 

 sheds of major drainage basins whence the water origi- 

 nated. Nebraska also has, in the Platte River Valley, an ex- 

 ceptional example of a watercourse from which ground water 

 escapes, flows under a topographic divide, and enters a differ- 

 ent watershed. There a decision as to the respective rights of 

 users in separate watersheds to water that has already been 

 used for irrigation requires a thorough knowledge of the 

 movement of ground water and its relation to surface water. 



76 Conover, C. S., "Ground-water Conditions in the Rincon and Mesilla 

 Valleys and Adjacent Areas in New Mexico," U.S. Geol. Survey, Typed rept., 

 October 1950, 316 pp. 



