New Paradigms for Pavement Stormwater Management

The primary concern in designing stormwater drainage for roadways and paved surfaces is to remove water from the pavement surface as quickly as possible. While that concern remains, dealing effectively with the quantity of stormwater is now complicated by heightened concern about its quality, and by efforts to retain most or all of the runoff onsite. In addition, this must all be accomplished with cost-effective methods and systems that promise extended service lives. This article discusses these challenges and describes some new products that are being offered to meet them. At least two paradigm shifts are impacting the stormwater industry. The first is that onsite retention is being promoted as the most effective method of pollution control, and the second is the shift away from peak flow mitigation toward hydromodification control. Although a wide range of stormwater infiltration techniques can reduce runoff volume, a common trend on roadway applications is to use a small-footprint stormwater treatment device. Both short-term construction costs and long-term maintenance costs are important to infrastructure owners, which requires additional focus on product performance and service life. The increased focus on water quality and stormwater management in highway projects and other land development, in addition to increasing emphasis on low-impact development (LID) and Leadership in Energy and Environmental Design certification, has created a need for innovative solutions. Combining multiple techniques such as LID with manufactured devices can address the wide range of factors that influence the use of stormwater management products and provide an opportunity to use a treatment approach that requires less space and less land disturbance.