Evaluating the Performance of a Hydrological Model to Represent Curbside Distributed Infiltration Wells in a Residential Catchment

Abstract

Stormwater managers use hydrological models to understand the runoff management performance of stormwater systems in urban catchments. However, few published studies attempted to evaluate the performance of hydrological models to represent water sensitive urban design (WSUD) elements at a catchment scale. This study reported on an evaluation of the Storm Water Management Model (SWMM) to represent a study catchment before installing leaky well systems in the catchment (preinstallation) and after introducing leaky wells (postinstallation). The process of representing individual leaky well systems using the user-defined hydraulic storage node or the built-in infiltration trench tools was also compared. The modeling approaches were evaluated against observed flow and infiltration data based on goodness-of-fit statistics, including the Nash-Sutcliffe Efficiency (NSE) and Kolmogorov-Smirnov (K-S) test for the catchment model. The results of goodness-of-fit tests and a K-S test indicated that SWMM can simulate a statistically similar runoff series to the observed series before and after the installation of leaky wells in the catchment. The ability of SWMM to model a leaky well performance using the storage or a built-in infiltration node was also evaluated using goodness-of-fit statistics against adopted criteria for good models. The results of model calibration and validations demonstrated that SWMM was able to simulate the performance of leaky well systems at the catchment scale, and the best performance was achieved by adopting a storage node to represent leaky wells. The model evaluation as per the adopted criteria indicated that the storage node model is suitable for assessing the impacts of leaky wells on stormwater runoff volume and peak flow rates.