Mexico and the United States sorely need to engage in “water diplomacy” over transborder groundwater sources, says Irasema Coronado, former head of the trilateral environmental body founded in 1994 in conjunction with the North American Free Trade Agreement (Nafta). Coronado, who led the Commission for Environmental Cooperation from Dec. 2012 to Jan. 2016, notes that while joint use of the Rio Grande, Colorado and Tijuana rivers is governed by binational accords, aquifers go largely unaddressed. The exception is the International Boundary and Water Commission (IBWC) Minute 242, a 1973 agreement that limits groundwater pumping to 160,000 acre-feet a year on both sides of the border near San Luis Río Colorado, Mexico and San Luis, Arizona.   Aquifers are a major part of border-region water supplies, which are strained by drought-induced declines in western U.S. snowpacks and the border-bound river flows they nourish. They serve border-straddling... [Log in to read more]