Assessment of extreme rainfalls and flood events over Da - Thao river basin under climate change impact

Abstract

This paper presents the projection of changes in extreme rainfalls in the Da - Thao river basin during the period 2021-2100 based on the dynamical downscaling model (WEHY-HCM) using the greenhouse gas concentration scenario RCP4.5. The results show that short-term extreme rainfalls are forecasted to increase in both subbasins in Vietnam and China. The trend of extreme rainfalls is not clearly detected corresponding to future climate periods; however, the greater changes are projected toward the end of the century in general. The intensity and frequency of extreme rainfalls with the period of 1 to 3 day(s) are projected to increase significantly in Son La and Lao Cai areas, while in Lai Chau and Yen Bai areas, those extreme rainfalls tend to decrease as compared to the baseline period 1991-2010. Therefore, the results of this study are considered to be a good reference at the river basin level to support decision-making processes on climate change adaptation and disaster risk reduction for downstream areas