SIUE Graduate Researchers Show Descrepancies in Stormwater Design Practices
As cities grow denser and rainfall grows more intense, engineers are increasingly asked to build on land already used for stormwater management. Two Southern Illinois University Edwardsville graduate researchers have shown that a common design assumption may leave these systems undersized. Their study, presented atthe 2026 Mid-America Environmental Engineering Conference (MAEEC) 2026, found that a single design storm can underestimate peak flows by up to 35%.
Nader Eldemiry and Abdelaziz Mahmoud, both graduate students and research assistants in Civil Engineering, presented their poster, “Building Over a Detention Pond: Applying the Huff Critical-Duration Method to a Wet Pond Retrofit in Indianapolis, Indiana,” atMAEEC 2026 on Saturday, Oct. 24. The conference, hosted by Missouri University of Science and Technology, drew more than 80 registrants plus many walk-ins. The work was supervised by Rohan Benjankar, PhD, assistant professor in the SIUE Department of Civil Engineering.
The study examined a redevelopment site in Indianapolis, developed through the DOTEC-SIUE Co-op Program, where a new building was planned over part of an existing pond. Some local codes size detention ponds using a single 24-hour storm. Instead, the researchers tested the redesigned pond against 40 storm scenarios using the Huff critical-duration method. They found the single-storm approach underestimated peak outflow by up to 35% and peak storage by up to 26%, showing that how engineers choose a design storm can directly change how large a pond must be.
“The research is focused on modern Green Stormwater management to maintain water quality, healthy ecosystem and resistance to future climate change impacts, which is different from traditional ‘gray’ infrastructure, which is merely focused on reducing storm water volume. This type of research and conference (MAEEC) attendance also a good opportunity for our students to enhance the knowledge from other researchers,” said Benjankar.
“Testing the design against a full range of storms showed us that a single design storm can miss the event that actually controls the pond’s size,” said Eldemiry. “Presenting at MAEEC let us share that finding with the engineers and researchers who make these decisions.”
“Many communities are trying to grow on land that is already part of their stormwater system, and those retrofits have to work just as well as the original design,” said Mahmoud. “Sharing our work at MAEEC and hearing feedback from experienced engineers was an invaluable part of my graduate education.”
PHOTO: From left: SIUE civil engineering graduate students Abdelaziz Mahmoud and Nader Eldemiry with their research poster at the 2026 Mid-America Environmental Engineering Conference, hosted by Missouri University of Science and Technology. Below, the conference attendees gathered for a group photo.
