Mount Vernon High School faced significant flooding issues due to heavy rainfall, which affected both the campus and nearby residential areas. Stormwater runoff accumulated at the southern end of the campus, posing a risk of overflow beyond the property boundaries due to the existing concrete masonry unit (CMU) walls. McLaren was brought in to perform a drainage assessment and address stormwater and retaining wall failures at the site.
McLaren began by reviewing documents, conducting field investigations, preparing a drainage report, and identifying long-term solutions with estimated construction costs.
We assessed the structural integrity of the Southwest and Southeast boundary walls, recommending reinforcement or replacement where necessary. A drainage study was performed to model current and future conditions, ensuring runoff would be contained within the property. McLaren also proposed four flood wall options, detailing their benefits, disadvantages, and associated costs. These options included temporary barriers, full wall replacements, a sheet pile wall, and an underground detention basin.
CMU Walls Evaluation: McLaren evaluated the existing boundary walls to assess their ability to withstand heavy rainfall and provided recommendations for reinforcement or replacement.
Hydrologic and Hydraulic Modeling: We conducted a drainage study using Soil Conservation Service (SCS) methods to prevent surface water runoff from leaving the property, providing cost estimates for viable wall solutions.
Runoff Mitigation: Modeling for both existing and proposed conditions was carried out to ensure effective mitigation of surface water runoff.
After our investigation, McLaren presented four remediation options, which included temporary flood barriers, full wall replacements at the same or new locations, and a sheet pile wall. Each option’s advantages and drawbacks were outlined.
McLaren provided detailed cost estimates for each flood wall option and recommended a more budget-friendly solution: installing smaller underground detention basin units in both paved and unpaved areas of the site.
