COUPLING INFILTRATION AND MORPHOLOGY MODELS TO UNDERSTAND SOIL DYNAMICS OF GREEN STORMWATER INFRASTRUCTURE

The use of Green Stormwater Infrastructure (GSI) allows for the attenuation of flow peaks resulting in less impactful runoff discharge into receiving water bodies. GSI systems have also been shown to be beneficial for significant water quality improvements for both organic and inorganic pollutants in urban areas. One major challenge for the sustainability of GSI is erosion and channelization due to high bed shear stresses developed during large storm events. Sedimentation within these systems has the potential to impact their performance as fine sediment tend to clog pathways necessary for infiltration. Understanding the geomorphology, shear stress and sediment flux in a GSI can help predict maintenance needs associated with erosion and deposition. We have created framework for addressing this problem by combining a geomorphic sediment transport model, FaSTMECH, with the Green-Ampt infiltration model to model GSI morphodynamics through time. A comparison of observed and predicted ponding depths shows strong agreement and demonstrates the ability of this novel framework in predicting the hydraulics and morphology within a GSI. This framework opens the door for planning and evaluating design alternatives to minimize impacts due to excessive erosion or deposition within a GSI.