Comparison of BMP Infiltration Simulation Methods

摘要

Prince George's County has developed a Best Management Practices Decision Support System (BMPDSS) to assist in assessing the effectiveness of Low Impact Development (LID) technologies. This module uses process-based algorithms to simulate BMP function and removal efficiency. The processes include weir and orifice outflow, flow and pollutant routing, evapotranspiration, infiltration, and a general loss/decay representation for a pollutant. Among these processes, infiltration is a key mechanism that controls the effectiveness of LID types of BMPs on both flow reduction and water quality improvement. Therefore, an accurate representation of the infiltration process is the basis of a successful BMP simulation module. The current version of BMPDSS employs the empirical Holtan-Lopez model. With the U. S. Environmental Protection Agency's support, the model is currently being enhanced to include a layered infiltration scheme using the process-based Green-Ampt method. This paper compares the performance of these two different approaches for simulating the infiltration process occurring in LID types of BMPs like bioretention, vegetated buffer strip, and bio-swales. The pros and cons of each method are discussed in this paper.