Research on the applicability of IFAS model in flood analysis (Pilot at Bang Giang river basin in Cao Bang Province)

Abstract

In climate change context, the increase of seriousness of natural disasters including flood is considerable. Thus, flood monitoring has been used to understand its rule and increase human subjective sensitivity on this catastrophe, in order to find management solution. However, this is not an easy job at national, regional and organizational levels because of lack of monitoring equipment, operational fund or lack of reliable data. To solve this problem, IFAS (Integrated Flood Analysis System) model was built. By using the input data which can be downloaded completely free for research, such as land use, elevation, especially rainfall data - this is completely new method comparing to current hydrological models. In this study, IFAS model is implemented at Bang Giang river in northeastern Vietnam. Through the algorithms of model, outputs are water level and discharge of surface, subsurface, aquifer, river course and vertical seepage in 3 forms: map, chart and table, showing the detailed information related to the flood. Assessing accuracy of the flow simulation model by relative error of the peak of flood (?Q) and Nash–Sutcliffe coefficient (R) shows that the flow simulation model achieves high accuracy in large rivers (?Q= -13.63%, R=0.93) and low accuracy in small river branches (?Q=+57.64%, R=0.44).