Flooding conditions in the Bayshore Drive residential area were the result of an undersized drainage system, an unmaintained drainage ditch with high velocities (up to 20 ft/s), and a brick wall restricting flow into the ditch. The City of Tallahassee contracted with SAI to analyze the drainage system and design drainage system improvements to solve the flooding concerns.
The project included development, calibration, and validation of an existing conditions stormwater model, a Phase 1 model that reflected post-improvements conditions from a completed City project, and a Phase 2 model to represent the Bayshore Drive Stormwater Improvements designed by SAI.
Working with the City, SAI developed construction documents for the design solution, including specialized high capacity curb inlet structures, nearly 600 feet of concrete box culvert constructed in a narrow right-of-way between residential properties, and a surface swale with ditch bottom inlets to collect surface runoff. SAI's design development required multiple iterations of stormwater modeling and, ultimately, the final design included removing portions of the existing brick wall restricting flow into the ditch and constructing pipe and inlet improvements downstream. Much of these improvements involved enclosing an existing ditch with a large box culvert and surface swale. SAI successfully permitted this project through the NWFWMD and USACE. SAI also prepared a FEMA No-Rise Certificate for the design under future build-out conditions.
This project won the APWA Project of the Year award. SAI is currently evaluating possible improvements to the upstream areas of the neighborhood under a separate contract with the City.