A federal judge has refused to allow USDA rules for on-farm wetland maps to remain effective after previously ruling they were adopted unlawfully.

Earlier this year, U.S. District Judge Tanya Chuktan declared the rules invalid, citing their potential to underestimate the size of wetlands.

The judge has now rejected USDA’s request to retain the rules because it “risks disruptive consequences for the environment,” while overturning the rules won’t cause “manifest injustice” to the agency’s Natural Resources Conservation Service.

“As the court has already acknowledged, NRCS’s change in policy has ‘allowed producers to drain and farm more wetlands,’” Chuktan said, quoting her previous decision.

Nearly four decades ago, Congress established wetland protections in the 1985 Farm Bill, which governs crop subsidies and other programs, requiring USDA to develop “inventory maps” of wetlands on farmland.

Due to controversies over how wetland boundaries were delineated, Congress imposed more rigorous standards for the maps in 1996.

The revisions only allowed USDA to deny Farm Bill benefits to growers who damaged wetlands “certified” under the standards established that year.

However, an internal audit later faulted the agency for relying on pre-1996 maps that often underestimated the actual size of wetlands on farms.

According to a lawsuit filed by the National Wildlife Federation, the policy was made official under wetland map regulations adopted by USDA in 2020.

The nonprofit accused the agency of permitting the “massive destruction” of wetlands by relying on outdated maps, but the USDA dismissed this characterization of the new rules.

Though the agency said its regulations complied with the requirements set out by Congress in 1996, the judge agreed with the environmental plaintiff that USDA violated administrative law.

Contrary to USDA’s arguments, the 2020 policy is “far more lenient toward certifying wetland maps” than the 1996 regulations, but the agency “did not give a reasoned explanation for that change,” Chuktan said.

After that ruling was issued, USDA urged the judge to “minimize disruption” by keeping the 2020 rules in effect while the agency reconsidered them.

The agency claimed procedural circumstances called for using a “less stringent” standard to determine if the regulations should be overturned, but the judge has now said that argument is irrelevant due to the “serious deficiency” in USDA’s rule-making.

“Even if the court applied a less stringent standard, however, the outcome would be the same,” she said.