Innovative Sigma engineering solution at retail center

franklin, wisconsin

This commercial development consists of a 1.6-acre parcel in the City of Franklin. It includes construction of two retail buildings with footprints of 4,200 and 6,000 square feet each with associated parking, drives and infrastructure. This was the first use of a pervious concrete pavement / stone detention bed for stormwater basins in Wisconsin, resulting in more buildable land that is especially suited for smaller in-fill parcels.

Services provided by Sigma include:

Civil / Site Engineering

The Sigma Group served as civil engineer on the project responsible for site design including design and permitting of stormwater management measures to meet City of Franklin, Milwaukee Metropolitan Sewerage District and Wisconsin Department of Natural Resources regulations. An innovative stormwater management approach utilizing pervious concrete with an underlying stone detention layer and under drain system was designed by Sigma to meet applicable regulations. The use of the pervious concrete pavement and underlying stone detention layer eliminated the need for a more traditional surface detention basin. The property was effectively developed without using valuable land to provide a surface detention basin.

In addition to the economic benefits, the porous pavement system provides environmentally sustainable features including zero discharge stormwater management, groundwater recharge and reduction of heat island effect.

Stormwater Management

Sigma performed monitoring of the stormwater management system for approximately one year after construction. The monitoring included measuring water levels in the stone detention bed and monitoring for discharge from the system to the public storm sewer. The results of monitoring indicated that the system functioned very efficiently with zero discharge to the public storm sewer system and minimal ponding of water within the stone detention bed.

Site Surveying / Mapping

Sigma prepared base mapping for site acquisition and design. Property staking and construction layout was also conducted.


On behalf of the Zabest Commercial Group, Sigma was honored to receive a special citation award at the 2006 SE2 Leadership Conference for an innovative stormwater management system utilizing pervious concrete pavement.

Sigma was honored to accept a Concrete Design Award in March 2007, presented by American Concrete Institute International (ACI International) and the Wisconsin Ready Mixed Concrete Association, for its part in the Rawson Commons development.

The award recognizes achievements in previous concrete pavement applications, and was awarded to Sigma for design of the pervious concrete pavement system used to provide stormwater management for the Rawson Commons development. The use of the pervious concrete pavement system eliminated the need for a conventional surface detention basin. The system was designed and is functioning as a zero stormwater discharge system