Author(s): Sathit Chantip; Nat Marjang; Kobkiat Pongput
Linked Author(s):
Keywords: Dynamic Flash Flood Hazard Index; Radar Rainfall; Soil Water Index; Rainfall Index; Flash Flood Potential Index
Abstract: Flash flood is a natural disaster that damages lives, properties and economies in many parts of the world. World Meteorological Organization (WMO) reports that more than 5,000 people died per year caused by flash flood. Forecasting flash flood hazard areas accurately during heavy rainfall situation will increase the efficiency of decision making in disaster response and management. This study introduces the preliminary development of a Dynamic Flash Flood Hazard Index (DFFHI) using advanced geospatial analysis technique and index-based approach in Wang River Basin located in the northern part of Thailand. The DFFHI is formulated from three indices lead to the occurrence of a flash flood. The first index is Flash Flood Potential Index (FFPI) which is a static map for flash flood risk assessment using geo-topography data. The FFPI comprises of eight physical- geographical factors: land use, vegetation index, hydrologic soil group, slope, profile curvature, plan curvature, flow accumulation and distance from the stream. The second index is Soil Water Index (SWI), which is the daily spatial soil moisture data and the last index is Rainfall Index (RI), which is calculated from the near real- time high-resolution radar rainfall data. The validation result between the indices and historical flash flood event location shows that DFFHI can locate flash flood hazard area closely to historical data. It is found that DFFHI has a potential to be used for flash flood forecasting and can be further developed to be operational to closely monitor flash flood hazard area during a heavy rainfall event. In addition, Convective Rainfall Index (CRI) and rainfall forecast data will be included in the future work for development of a Flash Flood Warning Index (FFWI).
Year: 2020