The Trump administration’s Navigable Waters Protection Rule has been vacated by a federal judge in Arizona who said allowing it to remain in place risks “serious environmental harm,” particularly in the arid Southwest.

Last month, a federal judge in South Carolina granted EPA and the Corps’ request to reconsider the rule without scrapping it. This time around, the plaintiffs, who include the Pascua Yaqui Tribe in Arizona and other tribes from around the country, persuaded a judge to get rid of it.

"This outcome ensures Clean Water Act protections are in effect while the Biden Administration works to develop a new rule," said Earthjustice, an environmental law organization that represents the tribes.

American Farm Bureau Federation President Zippy Duvall had a different take. “AFBF is extremely disappointed in the ruling," he said. "Farmers finally had environmentally responsible regulations that brought clarity to clean water efforts. This ruling casts uncertainty over farmers and ranchers across the country and threatens the progress they’ve made to responsibly manage water and natural resources." 

He noted that three separate courts had so far declined to vacate the rule. "Unfortunately, this Arizona court simply accepted the plaintiffs’ assertions as true and did something that no other court has done. We are reviewing the ruling to determine our next course of action."

Referring in her order to the Environmental Protection Agency and the Army Corps of Engineers, U.S. District Judge Rosemary Márquez said, “The seriousness of the agencies’ errors in enacting the NWPR, the likelihood that the agencies will alter the NWPR’s definition of ‘waters of the United States,’ and the possibility of serious environmental harm if the NWPR remains in place upon remand, all weigh in favor of remand with vacatur.”

The Biden administration is currently taking input on a new rule to replace the NWPR, but has yet to formally withdraw the rule itself. The government asked the court to remand the rule but allow it to remain in place. Arizona farm groups intervened to defend the NWPR.

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But during briefing of the case, the agencies expressed serious concerns about the implementation of the NWPR.

The judge cited a declaration from EPA Assistant Administrator for Water Radhika Fox in noting that EPA and the Corps “are concerned that the NWPR did not look closely enough at the effect ephemeral waters have on traditional navigable waters” when deciding to “categorically exclude ephemeral waters” from the definition of “waters of the United States.”

EPA and the Corps have “identified indicators of a substantial reduction in waters covered under the NWPR compared to previous rules and practices,” the judge said in her order. “Between June 22, 2020 and April 15, 2021, the Corps made approved jurisdictional determinations under the NWPR of 40,211 aquatic resources or water features, and found that approximately 76% were non-jurisdictional.”

The reduction in jurisdiction has “been particularly significant in arid states,” Fox said in her June declaration. “In New Mexico and Arizona, for example, of over 1,500 streams assessed under the NWPR, nearly every one has been found to be a non-jurisdictional ephemeral resource, which is very different from the status of the streams as assessed under both the [2015] Clean Water Rule and the pre-2015 regulatory regime.”

Márquez noted that “the business Intervenors,” including the Arizona Farm Bureau and Arizona ranching groups, “contend that a return to the pre-2015 regulatory regime would increase regulatory uncertainty. But regulatory uncertainty typically attends vacatur of any rule and is insufficient to justify remand without vacatur.”

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