Watertown must make plan to stop discharging wastewater into wetlands

Mar. 15—WATERTOWN — The city is trying to figure out how it can resolve an issue with untreated wastewater getting discharged into Beaver Meadows, a large wetlands west of the city.

It has happened for decades when the city alleviates residential flooding in the Butterfield Avenue area during periods of heavy, extended rains and rapid snow melts, according to a memo to City Council members from City Manager Kenneth A. Mix.

Last month, the city received a notice of violation from the state Department of Environmental Conservation for discharging the untreated wastewater into the wetlands.

The city has 30 days to submit a plan to the DEC to eliminate the unpermitted discharges. The city could be assessed penalties.

It all has to do with overcapacity of the western outflow trunk system on the city's south and southwest side, according to Public Works Superintendent Patrick W. Keenan.

The overcapacity is caused by infiltration of groundwater that seeps into sewer pipes through holes, cracks, joint failures and faulty connections, while inflow is stormwater that quickly flows into sewers from a variety of sources, including leaks in manhole covers.

To prevent neighborhood flooding, the city discharges the overcapacity — what is mainly rainwater — into the wetlands, Mr. Keenan said. The city had to resort to do it twice last year but not once in 2021.

In recent years, the city has made improvements to the system to try to resolve the issue, Mr. Keenan said.

"Apparently, it's not good enough" to have satisfied the DEC, Mr. Keenan said.

In 2019, the city also obtained a state grant to pay GHD Engineering, Syracuse, $75,000 to complete a study and come up with recommendations to resolve the issue.

The study found that 63 manhole covers in that part of the city had leaks, but it "has not found a smoking gun" for the reason it happens, Mr. Keenan said.

GHD is the same consultant that is coming up with a solution to reduce two disinfection byproducts that exceed acceptable levels at the Huntington Street water treatment plant.