As intense rain events test South Florida's stormwater management infrastructure, a group of University of Miami College of Engineering seniors is working on a solution to help a Miami-Dade community stay above the water.
Five environmental engineering students were tasked with developing a stormwater master plan for the Village of Palmetto Bay as part of their senior design project. Their goal is to design a state-or-the-art stormwater management system to better protect the community from flooding while also improving the quality of stormwater runoff that enters local waterways.
"The main issue in some areas of the village is flooding," said Courtni Spencer, a senior in environmental engineering. The current system, she said, "does not adequately handle the runoff and also does not provide adequate treatment of the runoff before it is discharged into the canals that run through the community."
Working under the guidance of David Chin, a professor of civil and environmental engineering in the Department of Chemical, Environmental, and Materials engineering, Spencer and her teammates Jessica Austin, Emma Gonsalves, Maria Mastrando, and Aobo Wang took as background an existing 2020 stormwater plan and analyzed a variety of priority areas identified by local officials and residents as having persistent drainage problems. After completing detailed hydrologic and hydraulic analyses, the students moved into the design phase, determining how new stormwater management infrastructure could be integrated into the existing system.
At the center of their proposal are exfiltration trenches, underground systems designed to store stormwater before it seeps into the ground. Unlike older slab-covered trenches that are much less efficient, or drainage wells that are less effective, exfiltration trenches allow stormwater to be retained in a perforated pipe surrounded by rocky material and at the same time exfiltrating into the surrounding groundwater.
"The point is to get retain the runoff, and also to make sure that when it goes into the groundwater or overflows into the canals it is of good quality and has some sort of treatment," said Spencer. "That increases the quality of both the groundwater and water in the local canals which eventually discharge into Biscayne Bay."
The team's design is engineered to withstand all 5-year storm events without causing any roadway flooding, and also provide treatment to the first inch of runoff, ensuring sustainability and effectiveness without unnecessary overdesign. By allowing for some ponding in lawns and roads, the students sized the trenches more efficiently, helping to substantially reduce construction costs. They also factored in future environmental changes, including projected increases to water flow tied to Everglades restoration efforts.
The first part of the stormwater master plan has already been submitted and received positive feedback from the Village of Palmetto Bay. The second portion, which includes final designs and supporting analysis, will be delivered later this semester for the village's consideration.
For Spencer, who grew up in Jamaica surrounded by the ocean, the project reflects why she chose environmental engineering.
"An engineer makes things that work in the real world. It could actually help a community," she said.
The team will present its final designs at the College of Engineering's Senior Design Expo on April 28 at the Shalala Student Center.
