'Bioswale' would reduce flooding on Riverdale Ave.

Walking or driving through the small business district on Riverdale Avenue near West 236th Street over the past few weeks, passersby may have noticed a large construction project on the expanse of pavement in front of the former Palombo Bakery. By next month, that unsightly hole will be a bioswale, a green space that captures running water, like rainfall or snowmelt.

The bioswale is a project of the Department of Parks and Recreation’s Green Infrastructure Unit. Director Ilan Kutok explained in a phone interview that the bioswale is designed to absorb water runoff from storms, preventing it from ending up in drains and, eventually, sewers.

When storm water fills the sewers, the pipes cannot handle the extra volume and it creates combined sewage overflow, or CSO. Every year, excess runoff causes tens of billions of gallons of sewage to pour into the rivers around New York City. The northwest Bronx is home to one of the biggest CSO outflows in the city, where the Broadway sewer overflows into the Harlem River. Despite that, the area has not been a priority in terms of CSO prevention for the Department of Environmental Protection (DEP), the agency tasked with handling the issue.

“This project is not built or funded under DEP,” Mr. Kutok said of the bioswale. “DEP is focused on [storm water] capture. Being we’re with the Parks Department, we have other parts to our mission.”

Mr. Kutok stressed the advantages of creating green infrastructure.

“We want to serve the social functions of the area and the environmental functions of the area,” he said. “We want to make it beautiful, spur economic activity and make people feel better about where they live.”

Mr. Kutok said when finished, the bioswale will be full of flowering trees, shrubs and perennials.

“There’s going to be an interior space creating a sort of plaza for this business district,” he said, adding that no parking has been eliminated. “We’re excited about it.”