Suffolk ditches storm-drain filter project

A pilot project to help protect Suffolk's waterways and underground water supply with a new technology to filter stormwater runoff has literally gone down the drain.

With it went the $850,000 the county already has spent.

Without an announcement, the county Public Works Department removed inserts that were supposed to filter contaminants from 214 of Suffolk's nearly 2,500 catch basins as part of a two-year trial.

Caught unaware, Suffolk lawmakers last week called in public works officials to explain their decision before the environment and planning committee. William Hillman, the department's chief engineer, said stormwater inserts proved "ineffective" because they became clogged much too often, and caused flooding.

"Our initial study showed the performance was satisfactory," said Hillman. "However, the performance rapidly degraded after a short time -- sometimes after one or two moderate rain events."

The inserts measure a foot in diameter and 18 inches deep. They were installed between an upper chamber that collected water and a lower chamber into which the filtered water dropped. Hillman said a typical rain on county roads produces stormwater totaling 1 cubic foot per second; the storm basins with inserts had capacity for only about 0.18 to 0.27 cubic feet per second.

Because of the potential flooding problems, Hillman said, public works was "extremely reluctant" to use the storm basins on county roads. Instead, they were reserved for 10 county facilities, including the county airport in Westhampton and highway maintenance yards. The filters even sparked vandalism, he said. Upset workers once used a pickax on a basin to improve the water flow, Hillman said.

An even greater concern -- with the county facing a $179-million budget shortfall -- was that catch basins needed almost constant cleaning to work properly. While the manufacturer touted the inserts as needing only an annual cleaning, the county had a contract to clear the filters every three months. It turned out they needed clearing monthly. "Very simply put, without continual maintenance these products . . . are ineffective," he said. "We do not have the resources to do that . . . it would be cost-prohibitive."

However, several lawmakers expressed concern that public works removed the units without installing anything to replace them. "So you're not doing anything?" Presiding Officer William Lindsay (D-Holbrook) responded.

"Why would we remove them and not have at least some mitigating tool out there to keep protecting our water?" committee chairwoman Vivian Vilora Fisher (D-East Setauket) asked.

But Hillman said that even without the inserts, the storm drains function as leaching basins, allowing runoff to filter through the soil before reaching groundwater -- a "best management practice," according to the federal Environmental Protection Agency. Also, of the 214 basins, only one in Yaphank that sent flows into the Carmans River fed into surface water, Hillman added.

Public works officials now are turning to "end-of-pipe" technology: a storm basin with two chambers. In one, water swirls and drops sediment, which contains 80 percent of pollutants. In the other, water moves up and down, releasing oils and hydrocarbons. Such basins can treat stormwater from the 20 to 40 catch basins to which they are linked, officials said.

Hillman said such systems have been installed at 20 sites, including the Forge River in Mastic, which has suffered serious pollution problems, and near the impaired Patchogue Bay. He said 13 more projects are set to begin next year. However, Hillman conceded that leaves more than 160 roadside storm basins, feeding local waterways in need of help.

"I wish there was a magic bullet," said Hillman. "Unfortunately, you can't believe all the . . . brochures you get."