Comprehensive numerical and physical modeling for investigating the flood event of the Barabai Region, Indonesia

Abstract The flood event in the Barabai region caused significant losses for the local community and infrastructure. Although efforts were made to mitigate the overflowing of the Barabai River, it is challenging to manage the flood event due to the limited and insufficient flood modeling. Hence, to improve future flood mitigation, comprehensive flood modeling is conducted in this study to model 42 km of the Barabai River using numerical simulations and physical modeling in the laboratory. Three scenarios are used in this work, including the existing condition and by adding a retention pond and drainage channel to accommodate the 20-year discharge of the Barabai River with a value of 451 m3/s. The results show a reduction in the maximum flood level from 2.5 to 1.5 meters and an inundation period from 16 hours to 4 hours, indicating that the proposed measures can effectively reduce the impact of future floods in the Barabai region. Our study shows the importance of combining numerical and physical modeling to investigate flood events comprehensively. While numerical modeling simulates and predicts flood impacts on a larger scale, physical modeling allows a more detailed understanding of the hydraulic processes in a more specific area. The framework presented in our study will benefit the related stakeholders to improve the flood impact prediction.