Developing extreme rainfall and flood scenarios for the Da River basin.

The national-level science and technology project, led by the Water Resources University, has completed extreme rainfall and flood scenarios and assessed the impact on large reservoir systems in the Da River basin, creating an important data and methodology foundation for forecasting, warning, and safely operating the structures in the context of increasingly complex climate change.

The project "Research on the construction and assessment of the impact of extreme rainfall and flood scenarios on large reservoirs in the Da River basin based on an integrated meteorological-hydrological model and dynamic displacement algorithm of atmospheric conditions" was implemented from December 2022 to November 2025, led by Dr. Tran Khac Thac from the Water Resources University.

The mission aims to build a database of major rainfall and flood events in the Da River basin.

The mission aims to build a database of major rainfall and flood events in the Da River basin; identify the causes of extreme rainfall and floods; establish an integrated method combining meteorological-hydrological models and dynamic displacement algorithms to simulate atmospheric conditions; and thereby generate extreme rainfall and flood scenarios to assess the risk of large reservoirs in the system.

According to the report, the research team identified the main causes of major floods in the basin, including moisture from storms, monsoons, and tropical convergence, often appearing as a combination of multiple weather patterns. Based on this, the team developed a technological process for calculating extreme rainfall and floods based on the integrated WEHY-WRF model, while also using a dynamic displacement algorithm to characterize the atmospheric conditions governing heavy rainfall. Flood simulations were performed on the WRF model after combining it with the output of the WEHY model, ensuring the consistency and reliability of the calculation sequence.

The extreme rainfall and flood scenarios were developed with high reliability, allowing for the assessment of risks to each large reservoir in the system. The results show that these scenarios not only help identify unsafe situations but also support the proposal of appropriate response solutions for the interconnected reservoir system of the Da River.

A large-scale rainfall and flood database system has been built on a WebGIS platform (http://itaes.vn/songda.html#), comprising three data layers: observation, augmented simulation, and presentation/display. The WebGIS system allows for quick and secure data access and sharing, supporting specialized agencies in reservoir operation and disaster prevention. The simulated rainfall and flood map layers can be displayed continuously over time, contributing to improved forecasting capabilities and risk visualization.

The results of the project offer broad application value for administrative agencies at both the central and local levels.

The results of the project offer broad application value for central and local government agencies, especially provinces in the Da River basin, as well as universities and research institutes. The data, models, and technical procedures developed provide an important scientific basis for planning, developing regional strategies, and improving reservoir management and operation capacity under extreme weather conditions.

These research findings add new knowledge to the mechanisms of extreme rainfall and flooding formation, while also creating an important scientific and technological foundation for warning, forecasting, and safe operation of large reservoirs in the Da River basin amidst increasingly complex climate change.

Center for Science and Technology Communication

Source: https://mst.gov.vn/xay-dung-kich-ban-mua-lu-cuc-han-cho-luu-vuc-song-da-197251211142929201.htm