RAINFALL RUNOFF AND INUNDATION IN CAU-THUONG-LUC NAM WATERSHED IN VIETNAM UNDER GLOBAL WARMING

抄録

 Summer monsoon brings over 70% of total annual precipitation to Vietnam northern mountainous region. The large amount of rainfall concentrated in a short time resulted in various flood-related disasters in many regions, especially in Cau-Thuong-Luc Nam (CTLN) watershed. Under the global warming, frequency and intensity of flood occurrence in CTLN watershed have been gradually increasing. There is an urgent need to establish the countermeasures for this key economic region based on the deep understanding of the hydro-meteorological characteristics of the watershed. In this study, we investigated the rainfall-runoff and inundation characteristics of the CTLN watershed in connection with the correspondence climate condition of the present (2000-2009) and future (2060-2069). The Rainfall-Runoff and Inundation (RRI) model was used for the simulation of watershed hydrological characteristics. The essential future precipitation inputs for RRI were achieved by using the Weather Research and Forecasting (WRF) model nested inside GFDL-CM3, and MIROC-5 models. Results of this study suggest the severe flood and inundation condition of the CTLN watershed in the mid-21^st century. We have found the increasing trend in total rainfall during the rainy season throughout the watershed. Compared to the present climate, both GFDL-CM3 and MIROC-5 models show the significantly stronger flood intensity with extended inundation radius.