Geographia Technica, Vol 15, Issue 2, 2020, pp. 29-39
FLOOD RISK AREAS SIMULATION USING SWAT AND GUMBEL DISTRIBUTION METHOD IN YANG CATCHMENT, NORTHEAST THAILAND
Haris PRASANCHUM 
, Panuthat SIRISOOK, Worapong LOHPAISANKRIT
ABSTRACT: Flooding problems have resulted in damage to urban and agricultural areas during the rainy season in the northeast of Thailand. Flood risk assessment at sub-catchment levels and proper explication of risk area can be guidelines for effective protection planning. This study aims to assess flood risk areas in the Yang catchment based on hydro-meteorological data between 2008-2016 by using the SWAT model for analyzing the maximum monthly discharge at each sub-catchment and fitted to the Gumbel distribution in order to evaluate flood risks in return periods of 2, 5, and 10 years. The results indicated that the calibrated the SWAT model can reasonably simulate discharge at the observed stations based on the statistical indicators such as R2, RE, and Ens. According to the Gumbel distribution methods, the western sub-catchments of the Yang catchment had a high level of flood risks. However, the other in the east sub-catchments were found to have lower levels of flood risks. The methods and results of this study can be useful tools and information for improving an understanding among stakeholders in the affected area in order to reduce damage from flooding in the future.
Keywords: Yang catchment, discharge, flood risk area, SWAT, Gumbel distribution.
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