Flood hazard assessment under climate change scenarios in the Yang River Basin, Thailand

Sangam Shrestha, Worapong Lohpaisankrit
2017 International Journal of Sustainable Built Environment  
11 Climate change is expected to increase both the magnitude and frequency of extreme precipitation events, which may lead to more 12 intense and frequent river flooding. This study aims to assess the flood hazard potential under climate change scenarios in Yang River 13 Basin of Thailand. A physically-based distributed hydrological model, Block-wise use of TOPMODEL using Muskingum-Cunge flow 14 routing (BTOPMC) and hydraulic model, HEC-RAS was used to simulate the floods under future climate
more » ... er future climate scenarios. Future climate sce-15 narios were constructed from the bias corrected outputs of three General Circulation Models (GCMs) for 2020s, 2050s and 2080s. 16 Results show that basin will get warmer and wetter in future. Both the minimum and maximum temperature of the basin is projected 17 to increase in future. Similarly average annual rainfall is also projected to increase in future, higher in near future and lower in far future. 18 The extreme runoff pattern and synthetic inflow hydrographs for 25, 50 and 100 year return flood were derived from an extreme flood of 19 2007 which were then fed into HEC-RAS model to generate the flood inundation maps in the basin. The intensity of annual floods is 20 expected increase for both RCP 4.5 and 8.5 scenarios. Compared to the baseline period, an additional 60 km 2 area of basin is projected 21 to be flooded with the return period of 100 years. The results of this study will be helpful to formulate adaptation strategies to offset the 22 negative impacts of flooding on different land use activities in Yang River Basin. 23
doi:10.1016/j.ijsbe.2016.09.006 fatcat:kmdlbd7vqjhofcnqd6ebjocfoi