Flood risk class determination in Tung Kula Ronghai using satellite data and GIS

Flood risk class determination in Tung Kula Ronghai, Northeast Thailand, was carried out using the satellite data and geographic information system (GIS). The objectives of the study trying to determine flood risk class in the study area based on satellite data, discharge data, cross-section profile of river. The analysis induced MIKE11-GIS for flood risk class modelling. The results of the study concluded that it can be divided the study area into 4 levels of flood risk class i.e., no risk, high risk, moderate risk and low risk. The study area had probability to encounter different extend of flood risk class or 12.87 percent of the total area was high risk, 28.46 percent was moderate risk, 28.43 percent was low risk and 30.24 percent was identified as no risk. According to the administrative boundary, high risk area were in Surin province of about 235.37 square km or 26 percent of the province area, while there were 108.48 square km or 7 percent and 90.16 square km or 20 percent located in Roi-Et and Si Sa Ket province, respectively. The moderate risk area for flood covered an area of 544.51 square km (35 percent) in Roi-Et, 256.16 square km (28 percent) in Surin, 115.14 square km (26 percent) in Si Sa Ket and 5.81 square km (2 percent) in Maha Sarakham. The low risk area for flood of about 359.98 square km (23 percent) were in Roi-Et, 326.50 square km (35 percent) were in Surin, 188.66 square km (41 percent) were in Si Sa Ket, 61.48 square km (20 percent) were in Maha Sarakham and 11.90 square km (12 percent) were in Yasothon. The influence of land use on flooding was allocated by overlaying the flood risk map and land use map. This found that high risk, moderate risk, low risk and no risk area covered an area of 246.21 square km (7 percent of the total area), 1,049.20 square km (31 percent), 776.87 square km (32 percent) and 1,299.72 square km (39 percent), respectively. It found that land use patterns including urban area, paddy field, mixed upland crop (cassava, kenaf, corn, sugar cane and etc.) and non agriculture area was located in high risk covering an area of 5.40, 149.00, 11.40 and 80.41 square km, respectively.