BACKSTORY

The Agua Caliente Band of Cahuilla Indians, in California’s dry Coachella Valley, relies on a rapidly dropping aquifer. In 2013, the tribe sued the Coachella Valley Water District to halt its groundwater pumping. Four years later, the U.S. 9th Circuit Court of Appeals ruled that the tribe has priority rights to groundwater beneath its land — a precedent-setting decision (“A tribe wins rights to contested groundwater in court,” HCN, 4/5/17).

[RELATED:https://www.hcn.org/issues/49.8/a-tribe-wins-rights-to-contested-groundwater-in-court]

FOLLOWUP

An August study published in Science clarified how much groundwater could be at stake. Nearly 240 Western tribes have unresolved groundwater rights, largely in Arizona, Oklahoma, South Dakota and Utah. The Stanford University study also noted, “This ruling establishes a new standard throughout nine Western states within the (9th circuit) court’s jurisdiction.” As water supplies dwindle with climate change and serious conflicts arise with other users, tribes will have major leverage in determining how Western water is allocated.