WATER POLITICS

The US Supreme Court has agreed to resolve a water dispute involving the Rio Grande River that’s been pending at the high court for a decade.

At issue in the case accepted for argument on Monday is the 1938 Rio Grande Compact, which apportions water between Colorado, New Mexico, and Texas.

The states have since agreed to a settlement, but the federal government opposes the consent decree, saying it imposes obligations on the US that it has not agreed to.

The case is one of “original jurisdiction,” meaning it started in the Supreme Court without first going through another court. A special master manages the day-to-day operations of the litigation.

Texas originally filed the case alleging New Mexico was taking too much water under the compact. In 2018, the court issued a unanimous opinion allowing the US to intervene and assert similar claims.

The Rio Grande Compact was approved by Congress in 1939 and apportions water in the river between its headwaters in Colorado’s Rocky Mountains and Fort Quitman, Texas, about 80 miles southeast of El Paso.

The consent decree integrates into the compact the effects of groundwater pumping and climate change on reduced flows in the Rio Grande and requires a more accurate accounting of water delivery and compact administration among the states, according to an amicus brief filed in the case by 10 water law professors. The decree also resolves ambiguities in Texas’ water allocation from the river, the brief says.

Texas filed its original jurisdiction case against New Mexico in 2014 for a compact violation, and the Supreme Court later allowed the federal government to intervene to pursue its own claims against New Mexico. The special master oversaw the settlement among the states and supports it.

The US said in a court filing that it objects because its claims against New Mexico have never been adjudicated and the federal government has not agreed to settle them. The Justice Department is asking the Supreme Court to deny the states’ motion in part because the states moved to enter into the consent decree without US consent.

However, the special master said the federal government’s consent wasn’t necessary, as Texas and the US were no longer aligned in their claims.

The US alleges that the consent decree would violate the Rio Grande Compact in part because it would measure water deliveries to Texas at the state line rather than at an upstream reservoir in New Mexico.

The federal government also objects because it alleges that the decree allows the states to “dictate” water apportionment without regard to the federal government’s interests downstream and approves more groundwater pumping than existed when the compact was struck in 1938.

The case is Texas v. New Mexico, U.S., No. 22O141.