Porous Pavement Alleys


The City has two alleys located near flood prone areas in the downtown area. Both alleys are located within three blocks or the Straight River, a water body listed on the 303(d) list for both turbidity and fecal coliform impairments. The native soil located in this area is sand, which provides for increased infiltration.


The City will study of different reconstruction and repaving approaches for these three alleys:.

  • Porous asphalt
  • Porous concrete
  • Standard imperious paving

The alleys are very close together and will have identical rainfall events. The City will monitor stormwater runoff from the three alleys over a three-year period. In addition to the stormwater benefits of the two porous alley treatments, this portion of the Project will generate valuable paired-watershed data about the performance of these three paving options.


The information and reporting from this work will include:

  • Construction cost data
  • Experience cleaning of porous pavements with city street sweepers
  • Installation experience and constructability
  • Long-term maintenance costs and variations
  • 3-year monitoring of stormwater flows
  • Visual inspection reports

Research Benefits

This information will provide valuable comparison data for the State and provide a stormwater application for City officials and citizens to observe and evaluate. The positive benefits of the porous paving to stormwater flows will provide neighborhood flood control and water quality improvements for the Straight River.