A federal judge in Mississippi ruled in two cases that his court didn’t have the authority to order the U.S. Army Corps of Engineers to complete an environmental impact study on repeated openings of a Mississippi River flood control structure.

U.S. District Judge Louis Guirola Jr. dismissed a lawsuit filed by the state of Mississippi against the corps and others over damage to the Mississippi Sound caused by openings of the Bonnet Carré Spillway north of New Orleans, the Sun Herald reported.

The judge also dismissed a similar portion of a different lawsuit filed by Mississippi Coast counties, cities and organizations. He didn’t dismiss a claim in that case that the corps violated a federal fishery conservation act.

The corps opens the spillway when the potential of the Mississippi River flooding New Orleans arises. It was completed in 1931 and has been opened 15 times since. Four of the openings were between 2018-2020, according to the newspaper.

Excess river water gets diverted to Lake Pontchartrain and then flows to the Mississippi Sound. Dolphins and oysters have been killed during lengthy openings as salinity levels decreased. River water also has threatened aquatic life by leading to the formation of algae blooms.

“Fresh water intrusion causes decreased salinity levels and results in adverse consequences to the Mississippi Sound and Mississippi Gulf Coast,” the judge wrote in his ruling. “However, federal courts are courts of limited jurisdiction.”

A third lawsuit was later filed by two nonprofit environmental groups for damages to endangered species caused by spillway openings. The case is still pending before Guirola.