The deal, to be signed next week at a ceremony in southern Arizona, for the first time sets specific terms for reducing Mexico’s share of Colorado River water during a drought. The river provides water supplies to New Mexico and six other U.S. states before crossing the border into Mexico. Uncertainty over what Mexico’s share would be during a drought is one of the major unknowns in river basin management, according to a report earlier this year from a University of Colorado research team.
The agreement makes curtailment of New Mexico’s share of the river’s water during a drought less likely, according to Kevin Flanigan, Colorado Basin manager for the New Mexico Interstate Stream Commission. The commission, a state body that oversees management of the state’s rivers, unanimously endorsed the agreement at a meeting Wednesday morning in Albuquerque.
The complex deal illustrates the interrelated nature of water management in the West, with cities like Albuquerque and Santa Fe now using imported Colorado River Basin water to meet municipal supplies. The imported water flows through tunnels beneath the Continental Divide in the mountains north of Chama, then travels down the Chama river to the Rio Grande. Colorado Basin water, via the San Juan River, is also a primary source of supply to many communities and farms in northwest New Mexico.
Under the pact, Mexico agrees to reduce its consumption of water during serious droughts, when Lake Mead, the large reservoir between Arizona and Nevada, drops too low. The deal also gives the Mexicans a greater share of surpluses when Lake Mead is unusually full.
By reducing the stress on Lake Mead during drought years, the agreement will reduce pressure on water users up and down the river, reducing the risk of conflict among the states that share the Colorado, said Interstate Stream Commission Director Estevan López.
That is increasingly important as the population in the basin continues to grow, while a new federal study concludes climate change will reduce available water supplies in the Colorado, López said.
“There will be a substantial gap between the available supply and the projected demand,” he said.
— This article appeared on page C1 of the Albuquerque Journal