Closure to “How Buoyant Flow Control Devices Can Reduce Pond Size Requirements” by Jeffrey S. Glenn, Elizabeth M. Bartell, and Jon Moody

Abstract

In the original paper, the authors make a claim that a buoyant flow control device, proprietarily named Thirsty Duck (TD), can be installed in a standard detention basin and will reduce the detention volume while simultaneously maintaining the outlet flows to the existing condition. The TD operates by providing a constant outflow at a variety of heads. In essence, it is an orifice that floats upon the water level and rises and falls with the water level. The ASCE proceedings paper provides a summary outline of the results of a much larger paper published online in 2011. This document will be referred to as the TD paper. The underlying computations can be found in RS&H (2011). This document will be referred to as the RSH paper. It is 279 pages in length and provides many pages of computer input and computer output sheets and some summary information. The TD paper indicates that three separate ponds (detention basins) were modeled, listed as Ponds 1, 2, and 3. Pond 3 is the same pond noted as POND33C in the RSH paper. The authors indicate that their hydrologic modeling of Pond 3 shows a reduction in storage volume from 7.61 to 5.07 acre-ft, a savings of 33.4%. It is this claim that the discusser has investigated. The discusser did not review Ponds 1 and 2 in either paper since it was nearly impossible to follow the methods, and the lack of drawings and basic information did not allow a review.