Consequence assessment of the La Giang dike breach in the Ca river system, Vietnam

The article presents the results of the dike breach for the La Giang dike, in the Ha Tinh province, Vietnam. The study combined a field survey and mathematical simulation to assess the consequences of the dike breach. Through the field survey, potential dike breach locations were specifically identified. This minimizes the number of calculation scenarios. The mathematical model was calibrated and validated with large floods in the area. The results show that the model is consistent with the observation data, with the Nash index at good to very good levels. A series of simulations were performed to assess the dike breach consequence. In each case, the study provided details on the inundation area and the number of affected residents for each inundation level by an administrative unit. Based on the calculated results, the degree and scope of consequence varied depending on the locations of the dike breach. This is very useful information for the decision-makers to establish different response plans for different emergency cases.