In 2021, the Florida Department of Transportation completed the design of the first roundabout in Columbia County, FL at the intersection of NW Bascom Norris Road and US 41. Unfortunately, the initial permitting approach was rejected by the Water Management District late in the design process. The Osiris 9 team was asked to step in to develop a new permitting approach and to revive the permit. This task came with major constraints including the inability to obtain additional Right-of-Way for stormwater ponds and the flood sensitive location of the project.
Our team successfully obtained a permit so that the project could move to construction by developing innovative solutions for both flood improvement and treatment. We updated FEMA’s flood study ICPR3 model to version ICPR4 and incorporated our proposed solutions to demonstrate flood improvement. The model included seven floodplain compensation areas. Treatment was justified by showing nutrient load reduction in modified swales in lieu of presumptive permitting requirements. The roundabout was successfully constructed in 2022.