Development of an Analysis Model for Storm Sewer Networks Based on Grid Units

The Storm Water Management Model (SWWM), used for the analysis of storm sewer networks in urban areas, enables precise analysis of watershed runoff, hydraulic analysis and backwater effect in conduits, and so forth. However, it requires the specialized knowledge in parameter extraction, sewer network configuration, and analytical operation, it is somewhat difficult to access at the general engineering companies. Therefore, this study developed a grid-based simplified analysis model that is more convenient in terms of schematic design and feasibility review of storm sewer networks. This model can be used to analyze surface runoff, storm sewer network, and stormwater storage connection configuration at the grid unit, and it uses simplified formulas for basic runoff analysis and storm sewer network flow and storage analysis. In addition, this model can review the rough effects of stormwater storage and various infiltration facilities that can be linked to existing storm sewer network through size calculation of grid units. The developed model was applied to the storm sewer network in the coastal area of Gwangalli, Busan, and our results were compared with the results of the Environmental Protection Agency's (EPA) SWMM. Similar results were obtained in terms of surface runoff and runoff within the storm sewer network, but there were some differences in the amount of storage and overflow. However, results were similar in the occurrence nodes and trends of overflow, and accordingly, it is expected to be useful for the purpose of this model and for simple feasibility studies of various design proposals and rough analysis results.