If you live or work in downtown New Haven, you may have noticed crews digging a bunch of new holes in the sidewalks.

This is called a bioswale. That’s not some aquatic mammal, it’s basically a hole designed to take water into the ground.

“So, a bioswale or a rain garden is a feature that is designed to collect excess runoff from the street and sidewalk,” explained Matthew Viens of the Urban Resources Initiative, the group spearheading the bioswale program.

Now, you may be thinking, don’t we already have a bunch of those holes? They’re called storm drains. Well, yes, but the whole idea is to have less water going down into the storm drain.

For years, New Haven has struggled with street flooding. The storm drain system is old. It’s powered by gravity, so in heavy storms, the lowest part by the police station, train station and post office all floods. And in some parts of the city, the storm drains flow into the water treatment plant, overwhelming the system and causing it to discharge raw sewage.

“We can deal with some of that water without overloading the storm system,” Viens said. “So we’re reducing that peak flow and hopefully reducing that downstream pollution as well.”

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They do that by tearing up pieces of sidewalk, cutting the curb to allow water from the street, and digging. An urban landscape is covered in concrete and asphalt, so this is an opportunity for some water to go directly into the ground, they way it naturally would.

“We dig down to a depth of five feet,” said Viens. “Underneath the garden, we first fill with about three and a half feet of gravel, and on top of that, we’ll put a mixture of sand and organic soil.”

That’s because, when they’re done, the bioswales are covered in plants. Doing much of the work is a program called Emerge that employs former convicts. They get a job and more.

“We leverage the opportunity. The opportunity to put people on payroll to get them to do things that they normally, historically are not willing to do: Parenting classes, literacy classes,” explained Reinaldo Cruz of Emerge.

So the program helps people, the city, and the environment. It’s run by the Urban Resources Initiative, which is a non-profit associated with the Yale School of Forestry. They’re doing so well, these Yalies just got the Roy Family Award from Harvard.

“Which is awarded to unique environmental partnerships that work towards issues of environmental and social importance,” Viens said.

Viens said the Yale folks did not even get run out of town when they went to Harvard. The plan is to build 275 bioswales all around the Elm City.