This story originally appeared on WNYC News.

 

It’s hard to see now, but New York City was built on marshes and wetlands. Minetta Street in Greenwich Village follows the path of the old Minetta Stream; Canal Street used to run alongside a canal.

Now, one of those forgotten streams could see daylight once again. The Parks Department is studying the possibility of restoring part of the Tibbetts Brook in Van Cortlandt Park in the Bronx.

During the early 20th century, the Tibbetts was buried. This was a good thing for those who owned the land through which the brooks ran: they could build houses, shops, and highways there. But burying it also caused new problems.

Once underground, the Tibbetts joins the sewer system, mixing fresh water with raw sewage from nearby neighborhoods. Then the mixture goes to a treatment plant.

The problems occur during rainstorms, when the volume of freshwater from the brook can double or even triple, overwhelming the treatment plant and forcing it to dump the untreated mixture straight into the Harlem River. During big storms, the sewers can also flood up onto the streets above.

One idea is to surface the Tibbetts Brook and route it along the Major Deegan Expressway. (Danny Lewis/WNYC)

One idea is to surface the Tibbetts Brook and route it along the Major Deegan Expressway. (Danny Lewis/WNYC)

By “daylighting” the stream, the city would divert the brook to a slightly different route above ground and keep it separate from the sewers. Green spaces on both sides of the stream would absorb storm water, just like the wetlands once did.

"We want to have the Tibbetts Brook do what it used to do: naturally go into the Harlem River," said Christina Taylor, executive director of Friends of Van Cortlandt Park.

While the Parks Department’s director of wetlands restoration, Marit Larson, likes the idea, she says it’s more complicated than it might seem, and could cost tens of millions of dollars.

A more limited feasibility study look at just one-third of a mile within Van Cortlandt Park should be out in June 2017.