Modeling bioinfiltration surface dynamics through a hybrid geomorphic-infiltration model

Abstract

Bioinfiltration systems are an increasingly prevalent mechanism for urban stormwater mitigation. One major challenge for the sustainability of bioinfiltration systems is erosion and channelization due to high bed shear stresses developed during large storm events. Sedimentation within these systems could also impact their performance as fine sediment may clog pathways necessary for infiltration. Understanding the geomorphology, shear stress, and sediment flux in the system can help predict maintenance needs associated with erosion and deposition. The current study introduces a framework for addressing this problem by combining a sediment transport model, FaSTMECH, with the Green-Ampt infiltration model. A comparison of observed and predicted ponding depths shows very good agreement (median Nash–Sutcliffe efficiency coefficient = 0.93) and demonstrates the ability of this novel framework in predicting the hydraulics and morphology within a bioswale bioinfiltration system. The framework introduced in this study opens the door to understanding sediment transport dynamics within a bioswale, which has the potential to advance planning and design to minimize impacts due to excessive erosion or deposition within bioswale bioinfiltration systems. HIGHLIGHTS Sedimentation is a major challenge to maintaining urban bioinfiltration systems.; Sediment transport is modeled by a hydro-geomorphic model.; The model is run and calibrated with a unique dataset of observations from a bioswale bioinfiltration system.; Predicting areas of erosion and deposition allows for the identification of areas at risk.;

Keywords

• best management practices (bmps)
• green infrastructure
• infiltration
• sediment transport
• storm water management
• surface water hydrology