River shows no evidence of contamination following discharge from sewer main break

Town officials said Thursday that a 10,000-gallon discharge of untreated wastewater near the Peconic River was quickly “mitigated” and there was no visible evidence of the discharged wastewater contaminating the river. 

Representatives of the State Department of Environmental Conservation and the Suffolk County Department of Health Services have taken water samples for testing.

The county health department’s Jan. 14 advisory urging the public to avoid recreation in tidal waters of the Peconic remains in effect. 

The discharge occurred Wednesday morning at about 10 a.m. during sewer work at the 203–213 E. Main St. construction site, according to the Riverhead Sewer District’s report to the New York State Department of Environmental Conservation. The district filed the report at 12:20 p.m. through the state’s Sewage Pollution Right to Know reporting system.

“During construction of a new sewer, an unknown lateral pulled away from the existing 12-inch diameter gravity sewer in the pipe trench,” the report states. The district estimated that about 10,000 gallons of untreated wastewater was discharged over 45 minutes. 

RiverheadLOCAL first reported the discharge Thursday morning after locating the DEC notice online.

Read more: Untreated sewage discharged into Peconic River following pipe break at E. Main Street construction site

The property under construction is being developed by Heatherwood with a 165-unit apartment building. 

Bypass pumping equipment already at the site for construction of a sewer pipe to connect the new building to the town’s sewer system was deployed Wednesday morning to convey wastewater around the area of the pipe break, so that the network of sewer pipes west and east of the break continued to function, Riverhead Sewer District Superintendent Tim Allen said in an interview Thursday after briefing the Town Board about the incident during its work session.  

Allen told the Town Board Thursday that the discharged wastewater “saturated into the ground” so “there was no cleanup.” 

The contractor has a dewatering box on site because the shallow depth to groundwater requires dewatering during excavation for sewer pipes and the building foundation. The dewatering system pumps groundwater out of the area being excavated, and pumps it up into the dewatering box, which is elevated. The box acts as a settling tank, allowing silt and other materials to settle at the bottom. Gravity moves the water to the river through a temporary pipe that runs across the site and across Heidi Behr Way.

Since the  dewatering pump could have pumped the discharged wastewater into the dewatering box, Allen told the board, he spent some time observing the contents of the dewatering box for any sign of untreated wastewater. There was no sign of it, he said. 

“I didn’t see anything. It was still nice, clean groundwater going out into the river — no smell, no odor,” Allen told the board. 

After the meeting, Allen elaborated in a brief interview.He said he believed the wastewater infiltrated sandy soil near the break and would have to move through groundwater before reaching the dewatering system wellpoints that extract groundwater. The wellpoints are about 20 feet deep, he said.

The wastewater filtered through the site’s sandy soil, Allen said.

The discharge “never went into the parking lot across the river. There was no direct contact,” he said. 

Allen said the town’s 12-inch sewer main that runs through the construction site cracked Wednesday, requiring the installation of a new section of pipe. 

The sewer main is almost 100 years old. “It’s an old cast iron pipe,” Allen said. It carries about 400,000 gallons of wastewater every day, and is the principal conduit of wastewater through downtown Riverhead to the wastewater treatment facility on River Avenue, he said.

Once the sewer connection is completed, both the 12-inch main and the new pipe that will serve the new building will be encased in concrete, Allen said. The town required the developer to install a new manhole on the western edge of the site to allow easy access to the sewer main. 

Allen said he’s confident in the repair that was made and doesn’t expect any  further action will be needed.

He said no soils were removed from the area of the break and he is not aware of any soil samples being taken by the State DEC or the county health department. Both agencies took multiple water samples for testing, he said and test results remain pending.