การประเมินความเสี่ยงน้ำท่วมในพื้นที่เฉพาะขนาดเล็ก กรณีศึกษา เขตนิคมอุตสาหกรรมนวนคร จังหวัดนครราชสีมา Flood Risk Assessment in Specific Small-Scale Area : A Case Study of Nava Nakhon Industrial Zone, Nakhon Ratchasima Province

Abstract

Flood assessment in small-scale areas, such as industrial zone , is increasingly challenging due to rapid urban development and land-use changes, which intensify surface runoff and flood vulnerability. The study area is located in the Lam Takhong River Basin. This study conducted flood simulations for both the Lam Takhong main river and its tributaries to compare the results at different levels of spatial resolution. Using the Hec-Ras hydrodynamic model, the simulation results indicated that the study area was not affected by flooding when considering the flood map generated from the Lam Takhong River alone. However, at the sub-watershed level, it was found that the study area is traversed by two small tributaries, Khlong Song Khon and Khlong Tha Yang, for ungauged catchments. Therefore, local rainfall statistics were applied to develop a Unit Hydrograph for flow estimation, which was then used as input for hydraulic modeling. The simulation results revealed that the study area experiences flood depths ranging from approximately 0.2 to 0.6 meters under a 100-year return period scenario. These findings highlight the necessity of conducting spatial-scale-appropriate analyses for small areas, considering their specific watershed context, and utilizing high-resolution DEM data along with appropriate hydrological modeling tools, rather than relying solely on streamflow data that may not exist for small study areas.