Research on the prediction of drought features in the Luanhe River Basin based on hydrological modeling under climate change

Against the backdrop of climate change and compounded by human activities, increasing water scarcity has triggered a series of drought disasters, which have already severely impacted both ecological environments and socio-economic production. The SWAT model, recognized for its strong portability and superior spatial heterogeneity, has gained widespread acceptance in fields such as hydrology and environmental science, and is extensively applied in hydrological simulation studies across large-scale river basins. Standardized drought index can effectively reflect the spatiotemporal variations of drought disasters, holding significant importance for clarifying and predicting drought characteristics. Here we took the Luanhe River Basin as the research area, constructed a watershed hydrological model based on SWAT, and projected changes in the basin’s hydrological processes for the period 2030 — 2060. Based on the model’s projected data, we calculated drought indices and extracted drought events for the basin. The results indicate: (1) During the study period, the range of annual runoff in the Luanhe River Basin reached 228.18 mm, while the range of average annual runoff across its sub-basins was 173.32 mm, revealing water resource allocation imbalances on both temporal and spatial scales. This issue is expected to intensify under future warmer and drier climatic conditions. (2) The mid-reaches of the Luanhe River are more prone to drought compared to the upper reaches for its higher water demand. However, due to a stronger capacity for ecological restoration, droughts there are mostly of low intensity in the mid-reaches. In contrast, the upper reaches experience more periods classified as severe or extreme drought, and the drought events encountered are generally more intense than those in the mid-reaches. (3) Anomalies in drought event characteristic values suggest a potential basin-scale, prolonged extreme drought event in the Luanhe River Basin from June 2038 to July 2042. Proactive drought prevention policies should be formulated for this period. The findings of this study provide guiding significance and practical value for drought assessment, risk management, and policy application in the Luanhe River Basin.