Small Rain Gardens Provide A Big Boost To Water Quality

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At first glance, the pair of new rain gardens on either side of the circular access road to Havens Beach in Sag Harbor don’t look like much — just an assortment of plants carefully arranged in planting beds that lie about a foot below the surrounding grade.

But the consultants hired by the village to oversee the project, which consists of a pair of roughly 800-square-foot beds that will fill in with hardy, native plants, say it will pay big dividends in the effort to reduce the flow of pollutants into the bay.

“The watershed of pretty much this whole driveway down to the parking lot is being captured into the rain gardens,” said Cassandra Castano, an assistant landscape ecologist with Nelson, Pope & Voorhis, the village’s environmental consultants, who designed the Havens Beach project.

The rain gardens are fed by French drains — little more than shallow trenches filled with gravel — that run parallel to the road and collect the initial runoff and direct it downhill to the planted depressions. The gardens can handle up to 1.2 inches of rainfall in any 24-hour period. That’s important, Ms. Castano said, because the first inch of rain carries about 80 percent of the contaminants — things like lawn fertilizer, fecal matter, traces of oil that leaks from cars — that would otherwise be washed into the bay.

“The plant roots capture those compounds and hold onto them,” Ms. Castano said, adding that the plants are hardy enough to stand up to pollutants like pesticides and insecticides that might be washed off of neighboring lawns. “So not only are the plants capturing that excess rainfall, but also cleansing it at the same time,” she said.

And lest people be concerned the gardens will retain the water and become breeding grounds for mosquitoes, Ms. Castano said the water collected by the gardens is absorbed back into the ground within 24 hours.

The project, which cost about $42,000, has been paid for with grants from the Peconic Estuary Program and the East Hampton Town Community Preservation Fund, according to Rusty Schmidt, a landscape ecologist with Nelson, Pope & Voorhis who has been overseeing a broader plan to use natural methods to tackle water quality issues across the village.

This week, Mr. Schmidt said that projects in that plan on both the Southampton Town and East Hampton Town sides of the village were approved by the towns, making them eligible for grants through the respective towns’ Community Preservation Fund programs, which now distribute a portion of their funding to water-quality improvement projects. Mr. Schmidt said plans are afoot to complete several more projects, including one to install permeable pavement on Bay Street at Marine Park and additional rain gardens along the park’s waterfront later this year.

Mary Ann Eddy, the chairwoman of the Sag Harbor Village Harbor Committee, said this week that rain gardens are important for improving water quality.

“Part of the solution is things like these rain gardens,” she said. “They are not just a classroom exercise. We have hard evidence they are needed, and it’s good for people to know that.”

Ms. Eddy said the Sag Harbor Water Quality Initiative helped bring the importance of clean water to the Village Board’s attention nearly four years ago when it hired Dr. Christopher Gobler, a Stony Brook University marine scientist, to sample water in Sag Harbor Bay.

Rather than just assuming the water was polluted, those tests, which were paid for through a public-private partnership, confirmed that water quality was, indeed, a serious issue, and one the village had to confront if it wanted to avoid more harmful algal blooms or spikes in fecal coliform levels that almost routinely force the closure of Havens Beach.

“It’s really been a been a community commitment to finding out what’s going on with our water,” she said.

And because of that commitment and the effort to obtain the data to make its case, the village has now qualified for more than $1 million in water-quality improvement projects, she said.
On Friday, Ms. Castano was busy arranging dozens of different plants, according to the plans she had drawn up, while workers with Roland P. Minnella Landscaping, the Brightwaters company that won the bid for the project, smoothed out mulch and did the planting.
There was New York aster to provide purple flowers in late summer and early fall, and showy goldenrod, a favorite among pollinators that has bright yellow blooms. There are coneflowers, which attract goldfinches and other birds, as well as buttonbush and winterberry, whose berries provide a winter food source for birds.
Other plants in the garden include bee balm, which attracts pollinators, prickly pear, whose yellow flowers bloom early in the summer; and common rush and switchgrass, both of which provide habitat and are good at intercepting pollutants with their extensive root systems.
The plants, all native varieties, are also chosen because they are deer-resistant, although Ms. Castano said planting a deer-proof garden is pretty much impossible. “They like to nibble on everything,” she said, “but these plants are not what they’re typically interested in.”
Rain gardens are something homeowners can do on their own property and are appealing to people who want to do their bit to help protect the environment. “People are opening their eyes to what’s important,” she said, “like providing habitat for birds, bees, and butterflies.”

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