253 - Unlocking the Power of 2D Watershed Modeling with Rain-on-Mesh in HEC RAS: Embrace the Sooner Solution

Hydrological and hydraulic (H&H) modeling plays a critical role in watershed management and flood risk assessment. This study incorporates an approach that harnesses two-dimensional (2D) modeling with rain-on-mesh (RoM) methodology to simulate hydrological processes within watersheds, with a specific focus on case studies from Iowa. The integration of rain-on-mesh within the HEC RAS addresses the challenges associated with capturing complex flow patterns and interactions between water bodies and terrain. This evaluation demonstrates the robustness of rain-on-mesh in accurately modeling rainfall-runoff interactions and surface flow dynamics, particularly on the rolling hills of Iowa. The temporal and spatial precision achieved through H&H modeling allows for the accurate representation of rainfall distribution across the watershed, leveraging data from NOAA Atlas 14. To accommodate the unique characteristics of large watersheds, both Diffusion Wave and Full Momentum equations are employed to determine the most suitable modeling methodology. Validation of the rain-on-mesh H&H models against real-world watershed data underscores their capacity to accurately replicate runoff and flood propagation processes. Sensitivity analyses to assess mesh resolution, precipitation input, and model parameters' impact, revealing optimal settings for large watershed modeling. The integration of RoM in HEC-RAS empowers stakeholders to embrace the "Sooner Solution," emphasizing the significance of timely and precise 2D watershed modeling for informed decision-making, reinforcing its potential as a valuable tool in the field of H&H modeling.