Author(s): T. Andrew Earles; James C. Y. Guo; Ken A. Mac Kenzie; Hayes Lenhart
Linked Author(s):
Keywords: Low Impact Development; Volume Reduction; Best Management Practices; Design Charts
Abstract: Reducing the volume of runoff is a fundamental concept of Low Impact Development (LID) that is critical for effective management of stormwater runoff in the urban environment. Representative Best Management Practices (BMPs) that provide volume reduction include bioretention (rain gardens), pervious pavement systems, grassed buffer strips, vegetated swales, infiltration basins and others. While the concepts associated with LID have been gaining acceptance in the United States and internationally, one of the remaining barriers to more widespread use is the need for the ability to better quantify the benefits of LID practices, especially volume reduction. This paper presents a simplified method for quantifying the volume reduction benefits of LID. First, a development site is divided into four land use types; (1) Unconnected Impervious Area (UIA), (2) Directly Connected Impervious Area (DCIA), (3) Receiving Pervious Area (RPA) and (4) Separate Pervious Area (SPA). Next, design charts developed using the United States Environmental Protection Agency (USEPA) Storm Water Management Model (SWMM) are applied to determine a impervious reduction factor. The design charts presented in this paper were developed by deriving a non-dimensional relationship between UIA, DCIA, RPA, SPA and other key variables including the pervious area infiltration rate, the design rainfall intensity and the Water Quality Capture Volume (WQCV) provided by storage-based BMPs.
Year: 2010