Increasingly stringent stormwater regulations at the local, state and federal levels are causing larger stormwater ponds. This reduces the amount of developable land and can sometimes affect the feasibility of a project. The intent of the new crop of regulations is to encourage land planners and engineers to design sites that reduce the volume of stormwater runoff generated in the first place in order to protect downstream receiving waters. This can be accomplished through the incorporation of Low Impact Development (LID) techniques and/or through on-site reuse programs. While these are the preferred methods, site constraints can make the practicality of reducing the runoff volumes to sufficiently low levels difficult if not impossible to achieve. Thus, providing additional on-site detention can be the only viable alternative. The Thirsty Duck Buoyant Control Device can reduce stormwater pond volume by 30-50%.

The Thirsty Duck Buoyant Flow Control Device is able to achieve reductions in pond volumes by providing a constant outflow discharge (instead of a discharge rate that diminishes as the pond depth drops), regardless of the water level in the facility, by suspending the outlet weir/orifice with a float at a constant depth below the water surface. The developer of Thirsty Duck has released an independent study performed on three SWM facilities in Florida; assessing the pond volume reduction achieved through retrofit of the existing facilities with a Thirsty Duck outlet device and the pond volumes that would be required had the ponds been designed with the Thirsty Duck device from the beginning. Based on this study, the pond volumes were reduced by an average of 36 and 44% for the two cases, respectively.

Since this is a new device, it is not incorporated in DCR's stormwater handbooks or in the BMP clearing house. But many localities allow innovative SWM/BMP designs – and the footprint reduction benefits may be worth the process in certain situations.

More information on the device can be obtained from the manufacturer's website www.Thirsty-Duck.com.