Sourced from the Living Architecture Monitor
Civil engineers who work in the field of stormwater management are facing considerable challenges, from regulatory agencies who are adopting green infrastructure approaches to extreme weather events that are challenging baseline assumptions. We caught up with Elizabeth Fassman Beck, who teaches at Steven’s Technical Institute in Hoboken NJ and is the Chair of the Environment & Water Resources Institute Urban Water Resources Research Committee’s Green Roof Task Committee and Mike Hardin, of Geosyntec to ask some tough questions about the practice.
1. In your opinion, how has civil engineering practice around stormwater management changed over the past ten years?
EFB: Stormwater infrastructure design objectives are usually dictated by regulation. Historically, regulatory compliance has been met with large, centralized facilities designed to reduce flooding, stream erosion (theoretically), and property damage from reasonably larger, infrequent events, and to provide water quality treatment (removal) of particulate-bound pollutants.
By now, we know that designing stormwater systems to address only these objectives fall very short of protecting our receiving environments and communities. Using technologies like stormwater green infrastructure (GI), and overall approaches like low impact development (LID), we should be minimizing runoff generation, trying to keep runoff and pollutants out of the sewers with small scale controls at- or near- the sources, and incorporating methods to minimize discharge of a wide range of pollutant forms. Maximizing natural hydrologic processes like infiltration and evapotranspiration and promoting stormwater harvesting and reuse are essential elements. Designing these functions to handle flows from smaller, day-to-day size storm events is critical.
Where we see wide-scale implementation of these ideas is where regulation has changed. Unfortunately, regulation remains the driver, and change is the exception rather than the rule. We have the technology. We need policies to catch up and enable advancement.
MH: In regard to stormwater management, I think there are still plenty or traditional grey infrastructure projects, but I am seeing more green infrastructure projects. Specifically, water quality improvement projects to remove nutrients from stormwater driven by total maximum daily loads (TMDLs), and NPDES permit requirements. More recently, the areas of resiliency and sea level rise have been given a lot of attention, especially for coastal communities. This is resulting in more modeling of extreme storm events and municipalities looking to make their stormwater infrastructure more robust and resistant to the effects of weather changes and sea level rise.
2. We keep reading about extreme weather events all over the world? How, if at all, is the profession dealing with the 'new normal' in terms of weather and climate?
EFB: In my opinion, dealing with extreme weather events is still predominantly addressed in a reactionary way. Looking forward, design resilience, and redundancy is the key.
MH: Being from Florida, this is very much a reality for the engineering community. I am starting to see more municipalities looking at long-term modeling and planning projects that assess the current state of drainage infrastructure and examine the resiliency based on different climate projections. Additionally, municipalities are looking to model more extreme storm events in their floodplain modeling to understand the potential impacts of a changing climate. This information is used to prioritize infrastructure upgrades in watershed wide planning.