The City of Dubuque will receive just over $9-million in state funds to conduct a pilot project aimed at reducing problems from groundwater runoff. Patti Cale-Finnegan with the Iowa Department of Natural Resources says the project involves renovation of what’s call the Bee Branch Creek.
“It’s a creek that was covered up years ago and kind of funneled through storm sewers. And so they’re actually going to open that back, create natural habitat, better water quality, and prevent flooding and address damage from storm water,” according to Cale-Finnegan. “And so one of the new pieces of protecting that creek is to infiltrate the rainfall in the alleys where it lands in the downtown area.”
One of the big pieces of the project involves paving the alleys with what’s called “pervious” pavement. “Most of our concrete and surfaces are impervious, water can’t soak through. This is a new approach using pavers that have spaces inbetween so the rainwater can actually soak into the ground. So instead of seeing sheets of water running off parking lots and streets, and in this case alleys, you actually have the water soaking in, infiltrating, and so it doesn’t run off as quickly.”
She says slower runoff prevents the water from scouring out the creek and also allows pollutants to filter out of the water before it gets to the creek. The project is being funded under a new approach.
“The state revolving fund program provides loans to cities for wastewater treatment upgrades, and so the City of Dubuque entered into a $64-million loan. They would pay normally, three percent interest, which would amount to about $30-million over the term of the loan. We are actually going to allow them to use about a third of that interest, or about nine-million dollars to put toward the pervious alley project,” Cale-Finnegan explains.
This funding approach may eventually be extended to other cities. “We have lots of needs with what’s called non-point source pollution or preventing runoff, whether it’s from farm fields or from city streets,” Cale-Finngan says. She says if this pilot project works, then they could use it to allow other communities to look at their needs.
The Bee Branch Watershed project is scheduled to be completed over the next three years. Planners estimate the project will keep approximately 750,000 cubic feet of water and 2,400 pounds of sediment each year from running into the Mississippi River.