A contractor with the city of Brookhaven believes a rodent could be the reason 6 million gallons of stormwater and sewage from the wastewater treatment plant’s storage lagoon leaked into the Bogue Chitto River.

After the leak was discovered Friday, the Mississippi Department of Environmental Quality issued an advisory for the segment of the river that stretches from Brookhaven to almost the state line.

“We’ve plugged the pipe which allowed us to contain the water. Our best guess is that it was undermined by a beaver or something similar,” said Ralph Augimeri with Mitchell Technical Services, which has contracted with the city for its water and wasterwater service since 2012.

MDEQ spokesperson Robbie Wilbur said the agency recommends individuals avoid contact with the water — swimming, wading or fishing — in the stretch that begins at the storage lagoon near Hwy. 84 to Walthall County south of Dillon’s Bridge near the community of Lehr until further notice.

“The city has made repairs, and there is no longer any discharge into the river from the breach,” Wilbur said.

“We had a breach on the northern levee of the lagoon,” Brookhaven Mayor Joe Cox said. “It has been contained and pressure equalized. MDEQ was in agreement with our work to remedy the situation and was on location (Friday).”

Augimeri said the advisory is a routine safety measure.

“It’s a precautionary matter,” he said. “They do it for any type of situation like this. It’s mainly a contact issue.”

The plant at Brookhaven, located at the intersection of Hwy. 51 and Hwy. 84, treats 3 million gallons per day. The storage lagoon contains about 80 million gallons of stormwater and diluted sewage, Augimeri said.

The 40-acre lagoon is across the railroad tracks east of the plant. Augimeri suspects a beaver may be the culprit.

“It looks like one of the burrows may have undermined the levee wall,” he said. “It took out a portion of the dike.”

Beavers are known to burrow into levees and chip away at the embankments. It hasn’t happened in Brookhaven before, but it’s a common problem around the nation, he said.

Augimeri said the leak was discovered Friday morning during a routine inspection and crews immediately put a temporary plug in it.

Cox said Greenbriar Digging Services of Brookhaven will begin repairs of the levee Monday.

MDEQ recommends that people should also avoid eating fish or anything else taken from these waters until further notice.  The agency will monitor the water quality and will revise the advisory as needed.