PHOENIX (AP) — The U.S. Bureau of Reclamation is launching two new groundwater basin studies, one in Arizona and the other in New Mexico. Bureau of Reclamation Acting Commissioner Alan Mikkelsen says growing imbalances between supply and demand are affecting many basins throughout the West. The Rio Grande Basin Study in New Mexico is focused on the Middle Rio Grande from the Colorado-New Mexico border to Elephant Butte Reservoir. The basin has been fully allocated since 1907, and future potential conditions in the basin could result in decreased water supply and quality. The Eloy and Maricopa-Stanfield groundwater basins in southern Arizona encompass most of the corridor between Phoenix and Tucson. The groundwater is being over-drafted by about 230,000 acre-feet per year and causing severe caving-in of land in the basins, putting critical infrastructure at risk.