Integrated Drainage Systems

Lawrence Technological University (LTU) is leading a collaboration of industry and academic partners in a multi-state demonstration project featuring the implementation of an innovative and scalable integrated drainage design that significantly mitigates polluted parking lot stormwater runoff. An integrated systems based approach for capturing and cleansing stormwater runoff is critical for protecting our Nations’ water resources and reducing human health concerns associated with combined sewer overflow (CSO) events in urban areas. An issue exacerbated by climate change which is bringing increased storm intensity and periling cities ability to manage stormwater and maintain water quality.

The integrated drainage system includes three separate patented technologies combined in a novel approach including a porous pavement surface (parking performance maintained), an underground engineered soil storage reservoir (for stormwater storage and water quality filtration) and an innovative drainage technology (to improve infiltration and reduce runoff). The integrated drainage system can replace 2.5 percent of the total parking lot impervious surface area and capture 90% of all rainfall events. After five installations (Michigan, Ohio, Florida, California, and Washington DC) and subsequent performance monitoring, Lawrence Tech expects to establish a national design protocol for advancing this novel integrated drainage system with a goal of improving water quality through innovation and regional technology transfer.

How does it work?

From the surface the project looks similar to a traditional parking lot, but the typical drainage system has been replaced. The top layer of the system is about the size of two parking spots and is covered in a type of porous pavement called Xeripave. Under the Xeripave is a six-foot deep excavation (20 ft x 25 ft) that has been filled with haydite stone to store up to an inch of rain. Underneath the layer of stone are Parjana EGRPs. The EGRPs balance soil moisture and facilitate water movement between horizontal soil layers.