Evaluation of augmented infiltration based LIDs for low lying urbanizing coastal catchments: a case study of Chennai city, India

The study assessed the effectiveness of infiltration-based Low Impact Development (LID) techniques and augmented infiltration LIDs (such as recharge shaft) in a coastal urban catchment in India using a semi-coupled approach between numerical models VS2DI and Storm Water Management Model (SWMM). Site specific VS2DI modelling indicated that the infiltration LIDs resulted in more saturation excess runoff due to the soil’s insufficient hydraulic conductivity and increased lateral flow. Catchment-scale modeling indicated that LIDs significantly improved water retention (<i>p</i> ≪ 0.05), with a 35% reduction in total runoff volume. The recharge shafts were shown to be more efficient in reducing runoff volume and peak runoff, particularly for high runoff rates (more than 22 mm/hr). The study suggests that direct recharge to the aquifer through recharge shafts could be a suitable solution to manage runoff and meet the demand for domestic water supply during times of water scarcity in coastal urban catchments.