The advantage of using satellite data together with the hydraulic model in flood hazard assessment: A case study in Ca River downstream

Abstract

In Vietnam, the Central area faced the highest frequency of flood; in 2020, 13 tropical depressions landed in Vietnam, 8 of them came to the Central area within more than one month, from the 7 th October to 15 th November caused a loss estimated at 30000 billion in Vietnam Dong(VND), and 249 people died. Flood management in this area is a crucial task for local authorities. In flood management, flood simulation is the critical task needed for every flood management strategy. Many methods can make the flood simulation. In those methods, hydraulic modeling is the widest apply in Vietnam. This method shows its advantages in many aspects, but they also have limitations compare to other methods. The hydraulic model can predict floods with complex conditions and multi-input. In this study, flood simulation is made by applying hydraulic modeling. The study area is downstream of the Ca river basin, affected area by flood in Central Vietnam. The flood simulation is made with four flood scenarios in MIKE packages: 1%, 2%, 5%, and 10%, representing the flooding return period of 100, 50, 20, and 10 years. The flood simulation provides flood map based on the modeling result. Those data is validated and compare with flood areas from satellite images in the study area. The study shows the advantages and disadvantages of hydraulic modeling in flood simulation and flood mapping from satellite images. There is a very high potential of using the hydraulic model together with satellite data for flood hazard assessment.