GREEN BAY, (WFRV) – Every time it rains or the snow melts, that dirty and untreated water ends up in our waterways. But after a recent construction project on Webster Ave. in 2019, steps to treat that water in a green way have been put in place with something called a swale.
“A swale is a vegetated ditch and the intent there is to route storm water through that ditch allowing the vegetation in the ditch or swale to take out pollutants that otherwise would go through our storm water system,” explained Green Bay Public Works Director Steve Grenier.
The swales help to filter out any dirt that comes from the roads and can lead to the water looking dirty. The vegetation in the swale also filters out phosphorous which the plants need to grow. That phosphorous is what can lead to algae blooms seen in the bay and Lake Michigan.
“Unlike grass which has shallow root systems, these plants have deeper rooting systems,” said Grenier. “They’re able to handle wider ranges in precipitation conditions. They’re drought tolerant and able to handle higher amounts of water as it comes in.”
And while the swale is a great option to intake and filter out storm water, there are other ways the city is using green infrastructure to help to tackle the storm water issue.
“One of the most common types of GI activities that you’ll see around is pervious pavement. And what that is is unlike conventional pavement like you see here on Webster Avenue, that pavement allows water to infiltrate as well,” added Grenier.
The director says that the city received a grant to install previous pavement during construction on Emily and Eliza Streets this year.