Urge Lake Montauk Cleanup
Immediate steps should be taken and community preservation fund money allocated to alleviate runoff of contaminated water into Lake Montauk and the Atlantic Ocean in Montauk’s downtown, the East Hampton Town Board was told at its work session on Tuesday.
Christopher Clapp of the town’s water quality technical advisory committee told the board that the committee recommends six high-priority actions deemed most feasible to achieve measurable improvements in Lake Montauk, where the Surfrider Foundation’s Eastern Long Island Chapter and Concerned Citizens of Montauk routinely measure dangerously high levels of bacteria.
Three proposed projects would be at the southernmost part of the lake, at the road end of South Lake Drive, which was once a bathing beach and the site of children’s swimming lessons. There, “we know we have bacterial contamination of some sort,” Mr. Clapp said, “suspected from septic systems but probably due to stormwater runoff as well.”
Mr. Clapp recommended construction of a wetland on the north side of Montauk Highway opposite Caswell Road to catch and filter stormwater before it flows into the lake. “The idea is to slow it down, let the plants and soils treat the water before it continues on,” he told the board.
Permeable pavement at the parking area there, and a regraded pavement, would pitch stormwater runoff into a pervious bioswale in the lot’s center to catch sediment and bacterial contamination before it enters the lake at the road end. A permeable reactive barrier, a device comprising trench boxes filled with ground woodchips or another reactive substance that intercepts groundwater as it seeps into a water body, was also recommended at the southernmost part of the lake to alleviate stresses from failing septic systems. A permeable reactive barrier has demonstrated an 85-percent reduction in nitrogen seepage at Pussy’s Pond in Springs.
“We’ll be looking at some engineering and porewater investigation of this south end . . . to try and find where the hot spot of groundwater contamination might be so that we can intercept that and begin to treat some of that water before it enters the saline waters and surface waters of South Lake,” Mr. Clapp said. “We think this may be a good opportunity to intercept a lot of the flow that’s coming from the Ditch Plains area by way of groundwater.”
Similar projects are recommended along West Lake Drive and on Star Island. Permeable pavement is recommended at the boat launch at both places to reduce runoff from their respective parking lots. Bioswales and rain gardens were recommended at the intersection of West Lake Drive and Flamingo Road and the triangles formed by West Lake Drive, Star Island Road, and North Fernwood Drive, “where we’ll be relying upon those swales, the soils, and the plants to strip a lot of the nutrients, bacterial contamination out of the water before it enters either the groundwater or the surface waters,” Mr. Clapp said. A permeable reactive barrier was also recommended at the end of Duryea Avenue.
Both areas of Lake Montauk, Supervisor Peter Van Scoyoc noted, “are adjacent to extremely densely developed areas, with the idea that septics are contributing” to water contamination.
A permeable reactive barrier “isn’t worth the effort in a lightly populated area,” Mr. Clapp said. “In order to make a permeable reactive barrier worth the effort, you want to identify where the highest-strength plume of contaminated groundwater is and at what depth it sits so you can engineer the product to fit the right spot. . . . This is the first step in engineering of the project.”
Additionally, the water quality committee recommends an engineering study to map the drainage area around the pipe that collects stormwater runoff from an upland subdivision near Surfside Place at the eastern edge of Montauk’s downtown. C.C.O.M. and the Surfrider Foundation have measured high bacteria counts at the pipe’s outlet on the beach.
Antimicrobial-coated stormwater filters in catch basins upgradient of the outlet pipe “should, in the short term, be able to drastically cut down the amount of bacterial contamination that’s coming out at the end of the pipe,” Mr. Clapp said. “It’s not to say it can strip everything, but the data that the company that makes these things has shown the committee have shown a drastic decrease in microbial as well as viral contamination in the water that passes through them.”
Before Mr. Clapp’s presentation, Laura Tooman, president of C.C.O.M., told the board that the group is supportive of the water quality committee’s recommendations. C.C.O.M.’s water quality data at South Lake Drive, which consistently exceed the federal Environmental Protection Agency’s standards for public health, demonstrate the need for action, she said. “I wanted to provide scientific data you need to show that there is a problem and something needs to be done. This is an instance where we know we have a problem, we have the resources to fix the problem, and, hopefully, we have the political will to fix the problem.”