Shellfishing restricted, but city sewage spill no longer to blame

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A two-mile stretch of coastal waters off Warwick will remain closed to shellfishing activities indefinitely due to high bacterial levels, although the size of the closure may be reduced in coming days to a more targeted area of observed contamination, according to officials from the Rhode Island Department of Environmental Management (DEM).

However, some may be surprised to learn that the continuing closure of a two-mile stretch, ranging from the southern coast of Conimicut Point to the extension of Ogden Avenue in the Highland Beach section of Warwick just north of Rocky Point, is not suspected to be caused by the a burst pipe that flushed an estimated 300,000 gallons of sewage into Buckeye Brook on Sunday, Aug. 26.

According to Angelo Liberti, Chief of Surface Water Protection for DEM, testing of affected waters commenced immediately following the overflow of wastewater near the Cedar Swamp pump station on Cedar Swamp Road. Testing of Buckeye Brook was conducted by the Warwick Sewer Authority, the Rhode Island Department of Health collected samples along Conimicut Beach and DEM conducted sampling of Narragansett Bay waters south of Conimicut and as far south as near Prudence Island.

Liberti said that, while initial testing – as to be expected – revealed drastic spikes in fecal bacteria colonies in the path of the sewage-contaminated water, subsequent tests showed that intervention methods conducted quickly by the Warwick Sewer Authority to bypass the area of broken pipes, chlorinate the water and the natural filtration cycles of the watershed pushed those levels back down to less severe, though still higher than normal, levels.

Water samples taken further out in the bay revealed no significant spikes in bacteria, so the initially large area closed to shellfishing was reduced on Aug. 31 to include just the immediate portions of coastal waters that are immediately fed by the Warwick tributaries, such as Buckeye Brook and Old Mill Creek.

DEM was prepared to begin testing shellfish specimens last week to gain insight as to whether or not the shellfishing ban could be wholly lifted sometime soon, and one shellfish sample came back free from contamination. However, they found unexpected bad news as well.

“Unfortunately, the water column numbers were quite high,” Liberti said. “Now, more or less we're comfortable that the effects of the spill are no longer being observed in Buckeye Brook or the bay, but there's another problem. We're going to have to keep the area closed until we get a handle on the variability of the fecal form colonies in the bay.”

Liberti said that the area of closure could potentially be further reduced pending more test results, but couldn’t provide a timeline on when that might be or what area could be reopened in the near future.

Charts generated from DEM and acquired by the Beacon show testing results from various locations around the affected portion of the Warwick coastline. In the area where Old Mill Creek flows into the ocean, bacteria levels came up higher on Sept. 7 than on Aug. 31 – a revealing that puzzles Liberti and DEM scientists but, at the same time, isn’t out of character for the waters in that area.

“We've known there is a historic bacteria issue in the watershed, but it wasn't impacting the shellfishing areas before,” Liberti said, mentioning that Buckeye Brook, Old Mill Creek and other tributaries in the area have been listed as “impaired waterways” since a DEM report was released in 2008 that chronicled bacteria levels in the waterways.

Liberti said that there are numerous factors that could contribute to high bacteria levels in the water, such as animal waste from dogs, wild animals and water fowl washing into stormwater drains or directly into the water.

“Having seen a number of these studies over the years, sometimes you just never know,” he said. “The person who collected the samples that day said there were lots of seagulls on the beach that day and that could be a source...Historically there has been some fluctuation throughout the watershed and we need to get a better handle on that.”

Liberti made a point to mention that DEM has been working with the city’s Department of Public Works to look for potentially leaking septic and sewer systems, and that the Warwick Sewer Authority had run a camera through another concrete pipe that may have been at risk of rupture. No significant septic leaks have been reported and the pipe was revealed to be in good condition, Liberti said.

Liberti also stressed that, again, all factors such as the time that has passed since the overflow of sewage and subsequent tests indicate the current high bacteria levels are not as a result of the sewage spill.

“Knowing the time it would take for water to flow from the pump station to the bay, and flushing within the bay, the die-off of bacteria and viruses in the bay, all those factors together, it would be implausible for this impact to still be from the sewer line,” he said.

In a release, DEM said it was planning to schedule a working group of stakeholders to discuss the issue of high bacteria levels in Warwick waterways, and “will continue to communicate with the public and work with partners to protect water quality and public health.”

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