Assessing the effects of climate change on flood inundation in the lower Mekong Basin using high-resolution AGCM outputs

• Published in: Progress in earth and planetary science 2020-07, Vol.7 (1), p.1-16, Article 34
• Main Authors: Try, Sophal, Tanaka, Shigenobu, Tanaka, Kenji, Sayama, Takahiro, Lee, Giha, Oeurng, Chantha
• Format: Article
• Language: English
• Subjects: 2. Atmospheric and hydrospheric sciences; Aquatic ecosystems; Atmospheric Sciences; Biogeosciences; Climate change; Climate effects; Climate models; Earth and Environmental Science; Earth Sciences; Environmental impact; Flood inundation; Flood magnitude; Floodplains; Floods; Geophysics/Geodesy; Hydrogeology; Lower Mekong Basin; Paper with Full Data Attached; Planetology; Projection and impact assessment of global change; Rainfall patterns; Rainfall runoff; Rainfall-climatic change relationships; Rainfall-runoff modeling; Rainfall-runoff relationships; River basins; River discharge; River flow; Rivers; Sea surface temperature; Stream flow; Surface temperature
• ISSN: 2197-4284; 2197-4284
• DOI: 10.1186/s40645-020-00353-z

Climate change currently affects the resilience and aquatic ecosystem. Climate change alters rainfall patterns which have a great impact on river flow. Annual flooding is an important hydrological characteristic of the Mekong River Basin (MRB) and it drives the high productivity of the ecosystem and biodiversity in the Tonle Sap floodplain and the Mekong Delta. This study aims to assess the impacts of climate change on river flow in the MRB and flood inundation in the Lower Mekong Basin (LMB). The changing impacts were assessed by a two-dimensional rainfall-runoff and inundation model (RRI model). The present climate (1979–2003) and future projected climate (2075–2099) datasets from MRI-AGCM3.2H and MRI-AGCM3.2S models were applied with a linear scaling bias correction method before input into the RRI model. The results of climate change suggested that flood magnitude in the LMB will be severer than the present climate by the end of the twenty-first century. The increment of precipitation between 6.6 and 14.2% could lead to increase extreme flow (Q 5 ) 13–30%, peak inundation area 19–43%, and peak inundation volume 24–55% in the LMB for ranging of Representative Concentration Pathways (RCP) and sea surface temperature (SST) scenarios while there is no significant change on peak flood timing.