Rainwater flows through porous pavement, allowing it to quickly reach soil.
That helps keep pavement clearer from ice and snow in the winter. And it also reduces the pollutants that rain can wash off of streets and into surface water.
Stormwater acts more naturally, like it did before so much of the environment was covered with city streets, said David Drullinger, environmental quality professional with the Michigan Department of Environmental Quality.
It sounds great, but it isn’t widely used even though it’s been around for a long time.
“It works about 50 percent of the time,” Drullinger said. “It gets clogged and sometimes it’s made clogged.”
Dirt, sand and other debris gets stuck inside the pavement and for it to be effective again it has to be cleaned, Drullinger said.
The pavement has to be vacuumed out once it’s clogged and there are a few machines able to do that.
“If you don’t have one of those don’t even think about putting it in because you have no way of keeping it clean,” Drullinger said.
There are few contractors in Michigan who are experienced with porous pavement, and that may be the problem, Drullinger said. As more contractors get experience working with it, the more effective it may become.
“Where it does work it is amazing,” Drullinger said. “Water just sucks right through.”
Despite these issues, several communities in Michigan are adopting the use of porous pavement for its benefits.
In 2006, the City of Battle Creek designed a driveway access and parking space using porous pavement at Willard Beach Park, said Todd Everson with the City of Battle Creek.
“The only issue is there are a lot of trees, lots of silt. Sweeping and vacuuming needs to happen often,” Everson said.
Battle Creek cleans the porous pavement at least once a year, but every six months is more desirable, Everson said.
“It’s being used in the more environmentally sensitive areas in Michigan,” said Daniel DeGraaf, executive director and corporate executive officer of the Michigan Concrete Association.
Ann Arbor, Grand Valley State University, Michigan State University, Battle Creek and Detroit all have porous pavement installments, DeGraaf said.
The Michigan Concrete Association is working to train and certify contractors to install porous pavement.
“One thing is it’s nice to have a new product that works but it’s terrible to have it done wrong and it doesn’t work,” DeGraaf said.
The method of installing it is different in that there needs to be a layer of rock below to allow water to drain through. If the base layer is done wrong, it could back up in heavy rain, DeGraaf said.
When constructing a parking lot, the whole thing is generally not going to be porous pavement. Developers will install strips of porous pavement throughout the parking lot that allows the regular concrete to drain into it, DeGraaf said.
This allows developers to use more land because they don’t have to set aside space for drainage ponds that would normally be required by commissions and codes, DeGraaf said.
Porous pavement also greatly reduces the need for snow clearing and salting in the winter. The porous pavement doesn’t allow water to remain on the surface, so ice cannot form, Drullinger said.
Areas in parking lots that are porous are noticeably clearer from ice and snow in the winter than the areas that are regular concrete, DeGraaf said.
As for the cost, it’s generally not much more than regular pavement, DeGraaf said. Installing porous pavement will cost a little bit more because of the water storage space that is required below the surface.gular concrete, DeGraaf said.
It is difficult to accurately compare the cost of porous pavement and regular pavement because the use of porous pavement is still somewhat specialized, DeGraaf said.
People are starting to look past the issues and see the benefits of porous pavement and because of that it’s gaining traction in the Midwest, DeGraaf said.
“If it’s done right it would be a good thing to use,” Drullinger said.