POROUS ASPHALT STREET MAKES ITS DEBUT IN IOWA 

October 22, 2009 

The City of Council Bluffs, Iowa, FOX Engineering, Western Engineering, Inc. and the Asphalt Paving Association of Iowa (APAI) are proud to announce the completion of the first porous asphalt paving street in Iowa – it is the final stage of the first phase of the East Manawa Lake Project in Council Bluffs, a multi-year improvement project that will replace over four miles of streets in the environmentally sensitive Lake Manawa area. The project included moving utilities, new water main and services, new sanitary sewer and services, eighteen inches of drainable stone base, new curb and the six inches of porous asphalt roadway

“We are extremely excited about the East Manawa project. The use of the porous asphalt pavement not only saved the people of Council Bluffs millions of dollars but it also recharges the water table of Lake Manawa, is environmentally sound, and has solved a long standing drainage problem there..”

Greg Reeder
Council Bluffs Public Works Director

The use of porous asphalt has been around since the 1970’s, but the need to manage stormwater in an environmentally responsible manner has pushed the use of the permeable pavement to greater importance. Traditional hot-mix asphalt (HMA) is a combination of sand, stone and approximately five to six percent asphalt cement (a petroleum product). Porous asphalt is designed with less sand, more stone-on-stone contact and high-grade polymerized asphalt cement. The resulting design allows water to flow freely through the pavement into the stone base, which acts as a retention pond, through a fabric liner and down into the soil sub-grade, thereby recharging the ground water table. Porous asphalt design does require that sand is not used in the winter and the road needs to be vacuumed twice a year to remove deleterious materials tracked onto the roadway. In addition to the environmental advantages, a recently discovered benefit of the porous asphalt pavements is that they seem to melt snow and ice even faster than traditional asphalt roadways.

“The use of a porous asphalt pavement was a benefit to this particular area on several fronts: this area is extremely flat and to place storm sewers would have increased the cost of this project by an additional $4,000,000 for the 430 home area, moreover, by using the porous asphalt pavements we were able to recharge the water table while filtering the storm water through the asphalt roadway and stone base.”

Scott Renaud
Project Manager, FOX Engineering


“The use of porous asphalt is not new to the State of Iowa; however, the use as a residential street is very innovative,” said Bill Rosener, Executive Vice-President of the APAI. ”to my knowledge there is only one existing porous asphalt subdivision in the United States (Oregon), and now the Council Bluffs East Manawa Lake project. This project lent itself to the use of porous asphalt initially based on cost but eventually the decision came down to respecting the environmental integrity of Lake Manawa. The design of this road will last the residents of this area for many decades to come.”

See Video of Water Truck Test