CASE STUDY: ENHANCED POROUS CONCRETE PAVEMENT SYSTEM CREATES ADVANTAGES FOR ALL STAKEHOLDERS

This paper covers the planning, design and performance monitoring associated with a porous concrete pavement system installed as an innovative storm water management approach for an approximate 1.6 acre retail development project in Franklin, Wisconsin.Planning for the project required that the development provide measures to meet City of Franklin, Milwaukee Metropolitan Sewerage District (MMSD), and Wisconsin Department of Natural Resources (WDNR) storm water management regulations and requirements. Given the nature of the development and and space constraints associated with the project site, utilization of an innovative storm water management approach using a porous concrete pavement system was considered early in the planning and preliminary design phase of the project. Enthusiastic acceptance of the concept by the developer (Zabest Commercial Group), the City of Franklin, the MMSD and the WDNR allowed the project to proceed without delay. The porous concrete pavement system was installed in April 2006 and has been functioning as designed since then.The pavement system consists of four inches of a proprietary porous concrete pavement (Ecocreto™) placed over a stone storm water detention bed. The permeability of the porous pavement system is approximately 4 inches of rainfall per minute and the stone detention bed beneath the pavement provides for storage of the 100-year, 24-hour rainfall event volume over the entire site.The system was designed and is operated as a zero storm water discharge system. Monitoring of the pavement system since its construction has shown no surface discharge of storm water from the site. This reduces the potential for downstream sewer surcharging and flooding, reduces downstream pollutant loading and provides for groundwater recharge.This paper examines the design and technical details associated with the implementation of the pavement system including an examination of regulatory requirements pertaining to storm water management that were applicable to the development project. System performance monitoring is presented and evaluated. Pavement system costs including on-going maintenance costs are also evaluated and compared to costs associated with a more conventional pavement and storm water management system. Advantages accrued to the various stakeholders are also discussed.