Permeable pavers solve drainage issues
When Ohio Street just east of downtown became an obstacle course because of pooling water from heavy rains, the City of Indianapolis looked for answers to ease the flooding.
Instead of building more sewer lines and drains, city officials in 2011 elected to go with an up-and-coming idea -- permeable pavement, which works as a sponge to soak the water through the pavement and into the ground.
"There was a real lack of drainage infrastructure in that area," says John Hazlett, former director of sustainability with the city who now works with Williams Creek Consulting in Indianapolis, which oversaw the Ohio Street project and a second one on South Alabama Street in downtown. "There was a lot of ponding on the sides of the street. We did pervious sidewalks and pervious curbs and gutters. The soils in that area are great for infiltration of storm water. Since then, we have gone out there and taken pictures after heavy rains, and the water disappears very quickly."
On a smaller scale, homeowners can also benefit from the convenience of permeable pavers as a solution to drainage issues, as it has become a formidable foe at eliminating excess rainwater, while providing an eco-friendly alternative in the process. Although not as popular yet in this area, Hazlett says it is big on the west coast, with some local governments offering tax breaks for homeowners with pervious pavement.
Unlike traditional pavement that is graded to push water runoff out into the street and to the nearest drain, permeable pavers are actually designed so the water goes through the joints between the pavers and into a gravel base system below. The pavement, which is noticeable by its gray color and cottage cheese-like texture, can also prevent landscape erosion by stopping the water from filtering on to yards.
“The big benefit is there is no need for much subsurface drains, piping and sewers,” says Bob Jackson, owner of highly rated Indianapolis-based Mr. Concrete of Indiana. “If you have a driveway, you won’t have to be as worried about drainage. The water runoff can be used to water your yard, or the water can go back into the ground water.”
Because such a system prevents any runoffs, it is considered an eco-friendly alternative to the environment because it prevents debris and chemicals from spilling into storm drains and eventually into waterways, such as lakes and rivers. The gravel base filters the pollutants and keeps them from re-entering the ground.
“It becomes beneficial in places where drainage can become a problem and in places where sewer lines maybe can't go,” Jackson says.
With permeable pavement, Jackson says about 12 to 14 inches of crushed stone is put in a subbase, which is then rolled and compressed into a high density. The water that goes through the pavers is fed into a storage tank where it goes to recharge the ground water supply.
Porous pavement can cost two to four times as much as regular pavement, Hazlett says, but can be beneficial in the long run. Very little maintenance is involved, he says.
"The advantage is infiltrating the storm water runoff rather that getting it into the sewer," Hazlett says. "That would eventually result in sewer overflows. You're saving on infrastructure."
These types of projects are better left to the professionals, Hazlett says. The process involves removing hundreds of pounds of dirt and can result in uneven pavement. When choosing a company, make sure they are qualified to work with porous pavement. The Interlocking Concrete Paver Institute offers certifications and guidelines for professionals.
"The installation is really key," Hazlett says. "And getting the proper pores is very important. It's a rather new technology, so you want to go with companies that have done these projects before."
Editor's note: This article was originally published in March of 2013.