PLAINVILLE — Porous pavement and other materials added to a new parking lot at Trumbull Park will help keep the nearby Quinnpiac River clean.

The 4,000 square feet of special pavement and two underlayers of crushed rock are expected to help clean 400,000 gallons of storm run-off each year, said Kendall Barbery, green projects coordinator for the Save The Sound program of the Connecticut Fund For The Environment.

"It helps in two ways. It allows runoff from 16,000 square feet of pavement to seep into the ground instead of going directly into the Quinnipiac," she said Monday. "The water is cleaned — we call it "polished" — by passing through the layers of crushed stone. It also helps by getting water into the underground aquifer that otherwise would run into the river without seeping into the ground."

The town council approved the project In March. Town Planner Mark Devoe said the town adopted a low-impact development policy a few years ago that requires runoff filtering systems. "The ground and vegetation take up hydrocarbons and heavy metals. We think it's a good way to go," DeVoe said in March.

The permeable parking lot sections are near the Trumbull Park ballfields. The parking lot work is part of a multistage process by the Connecticut Fund For The Environment to reduce run-off and capture rainwater, clean it and return it to underground water supplies.

Similar work will be done this summer in Wallingford's Vietnam Veterans Memorial Park.

Other work in the project was the installation of nine rain gardens that will capture runoff from a building roof and sink it in the earth to be cleansed and returned to the aquifer.

Money for the work is coming from a settlement in the long-runnig case of groundwater contamination at the Old Southington Landfill during the 1970s. That contaminated area was one of two toxic waste sites in Southington that the federal government designated as Superfund sites; the other was the site of the former Solvents Recovery industrial waste recycling plant.