Huntington Town has finished construction of a 6,100-square-foot rain garden at Centerport Beach — a $276,000 project that uses landscape engineering to naturally capture storm-water runoff and filter out pollutants through the soil.

The garden’s cost was offset with a $137,000 match from the National Fish and Wildlife Foundation’s Long Island Sound Futures Fund. Town officials said the goal is to filter 80 percent of the storm-water runoff before it reaches Centerport Harbor — and make a measurable improvement in water quality levels.

“People may look at the rain garden and think it was built purely for aesthetic reasons,” Huntington Supervisor Frank P. Petrone said in a news release. “Actually, the town has created a natural filter for water that will go a long way toward helping to clean up Centerport Harbor.”

Town officials said they expect the project to help reduce the number and severity of harmful algae blooms, which can lead to the closure of shellfish beds. Lowering the level of pathogens in the water can also minimize beach closures for swimming.

Rain gardens are typically 6-inch to 12-inch basins dug in the ground, filled with compost and plants, and placed strategically to catch storm-water runoff. The soil filters contaminants such as heavy metals, oil, pesticides, sediment and pet waste.

The Centerport rain garden replaces a 6,900-square-foot section of parking lot at a critical location to intercept water that had flowed directly into the harbor.

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“There was a tremendous amount of surface storm-water runoff,” said Joe Cline, director of Huntington’s department of engineering services, which designed the project. An added benefit, he said, is that “Centerport Beach is much prettier than it was before.”

Because of the area’s hilly topography, the main section of the garden was built as a 21-foot by 258-foot “bioswale,” which is deeper and larger than traditional rain gardens so it can intercept greater volumes of storm water. The project includes an adjacent traditional rain garden that is 1,228 square feet and connected to the bioswale by an underground pipe.

The garden includes 75 new trees and eight types of native plants. Pedestrian paths around the garden were made of permeable pavers — material that filters storm water. The garden’s north side curb is higher than the rest of it to catch and slow the flow of excess water during heavy downpours.

Huntington is partnering with the nonprofit Citizens Campaign for the Environment to educate the public on the project and its benefits. The group is developing an information kiosk at the beach and a video to explain the rain garden to visitors, said Adrienne Esposito, executive director of the campaign.

“The rain garden is a small project with a big meaning,” Esposito said in an interview. “It will provide cleaner water, it protects public health and it will be beautiful.”