A 2D rain-on-mesh model for simultaneous hydrologic and hydraulic computation

An increase in air temperature caused by global climate change has increased the moisture-holding capacity of the atmosphere. This resulted in an intensification of precipitation magnitude and frequency. As a result of this, areas within the mid-west have seen several episodes of floods caused by such precipitation events. Engineers and scientists have consistently improved the hydrologic and hydraulic techniques to quantify the severity of flood events. The rain-on-mesh approach is a new advancement in rainfall-runoff modeling technique that enables to perform simultaneous hydrologic and hydraulic computations. This helps in increasing the modeling details while minimizing errors and model complexity. The rain-on-mesh models often known as the rain-on-grid model are spatially detailed by discretizing the entire model into two-dimensional (2D) finite elements also known as 2D cells or 2D computation cells. The hydrologic losses and runoff are calculated for each 2D cell and are further routed through downstream 2D cells for evaluating spatially varied flood depths and velocities. The current research will test the applicability of the depth-averaged Hydrologic Engineering Center River Analysis System (HEC-RAS) 2D rain-on-mesh model, to evaluate the rainfall-runoff upstream of East Branch Du Page River at Bolingbrook, IL. The watershed has an area of approximately 75.8 square miles and has observed multiple flood warnings in the past. A spatially detailed yet simplified 2D model for evaluating the flood magnitude and extent can be a beneficial tool for the community and stakeholders.