Department of Environmental Protection Commissioner Carter Strickland displayed four new bioswales on Dean Street in Brooklyn this week.

Bioswales are vegetative pits on the side of the street that contain layers of soil, sand, and gravel. DEP said their introduction will filter storm-water slowly to prevent New York’s sewers from overflowing. The construction of the bioswales is part of the NYC Green Infrastructure Plan which is meant to build green infrastructure over the next 20 years. Stickland said construction on the four bioswales on Dean Street will be complete by the end of November. He said the city are planning to build 10 bioswales city wide.