A RASTER-BASED STORMWATER SIMULATION MODEL AND ITS APPLICATION IN INUNDATION MITIGATION PLANNING

Abstract

A raster-based stormwater simulation model is formulated and applied in this study. The proposed model employs the raster-based distributed approach for describing the surface rainfall runoff process. Surface runoff is generated from each grid cell and then is routed to the inlets/manholes of drainage channel network by using 2-D diffusion wave. The hydraulic process in the drainage channel network is performed by using the EXTRAN module, a component of the Storm Water Management Model (SWMM) . The input flow rate at inlets is calculated by using weir equation. The surcharge outflow rate from the drainage channels is calculated by using Preissman slot concept. The proposed model is successfully applied to reproduce the heavy flood event on August 4, 1998 in Kamedagou basin, Niigata Prefecture, Japan. Further more, the well-calibrated stormwater simulation model is utilized to inundation mitigation planning in the study area.