Đánh giá rủi ro hạn hán tổng hợp cho lưu vực sông Ba, Việt Nam

Abstract

Drought is one of the most complex natural hazards to assess due to its stochastic nature, wide-ranging impacts, and propagation across multiple components of the hydrological system. This study develops and applies an integrated framework for integrated drought risk assessment in the Ba River Basin, simultaneously incorporating three drought types (meteorological, agricultural, and hydrological) and accounting for drought propagation processes. The Drought Hazard Index (DHI) was computed as a continuous monthly time series for 1980–2023, and combined with a Drought Vulnerability Index (DVI) derived from socio-economic indicators to construct an integrated Drought Risk Index (DRI). From this long-term dataset, four representative drought years (2015, 2016, 2019, and 2020) during the dry season (January–April) were selected for detailed analysis. Results indicate that risk hotspots are concentrated primarily in downstream areas, where high hazard levels coincide with elevated vulnerability. The 2015–2016 droughts were particularly severe across middle and downstream districts, with many areas reaching high-risk levels, whereas in 2019–2020 risk was more spatially dispersed, affecting selected upstream and midstream districts at moderate to high intensity. This approach not only overcomes the limitations of univariate indices but also provides a more comprehensive understanding of drought risk, enabling the identification of priority “hotspots” for management. The findings offer a valuable basis for developing strategies to mitigate drought risk and enhance adaptive capacity in the Ba River Basin.