RS&H was selected by Thirsty Duck, Ltd., to analyze the effectiveness of its Buoyant Flow Control Device, an innovative outfall structure designed to improve the efficiency of stormwater ponds. The technology operates on the constant head principle and has the ability to produce a constant flow rate regardless of the depth of water above the flow control device. These devices can be used to minimize retention or detention storage volume, therefore reducing the required pond area and volume by maximizing and maintaining a constant outflow rate.
RS&H identified existing stormwater ponds in three geographic locations to test the device: the South Florida Water Management District, the Southwest Florida Water Management District, and the St. Johns River Water Management District. The team then documented the pond and basin parameters that were designed with traditional control structures and analyzed the ponds using a Thirsty Duck Buoyant Flow Control Device in place of a traditional control structure.
RS&H worked with Thirsty Duck in an iterative process to determine the optimum outfall structure and pond geometry for each pond. The team modeled the ponds with a hydrograph produced by Thirsty Duck to demonstrate a pond with a Thirsty Duck Buoyant Flow Control Device outfall structure. RS&H then modified the geometry of the existing ponds to demonstrate the pond area and volume reduction made possible by the Thirsty Duck Buoyant Flow Control Devices. This process was continued until the optimum Thirsty Duck Buoyant Flow Control Device was finalized and the pond volume was minimized.
RS&H compiled the results of the analyses in a report that Thirsty Duck can use to market their product to interested customers. Additionally, RS&H prepared and submitted a specification to the Florida Department of Transportation for the Thirsty Duck Buoyant Flow Control Devices to allow easy use by designers and contractors.