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| DOI：10.13522/j.cnki.ggps.2024433 |
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| Temporal dynamics of hydrological drought and its drivers in the Poyang Lake |
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WANG Nong, HAN Huiming
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1. Jiangxi Academy of Water Sciences and Engineering, Nanchang 330029, China;
2. School of Infrastructure Engineering, Nanchang University, Nanchang 330031, China
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| Abstract: |
| 【Objective】Poyang Lake is the largest freshwater lake in China, playing a vital role in regional water supply and ecosystem functions. In recent decades, however, it has experienced increasingly frequent and severe hydrological droughts. In this paper, we analyze the temporal variation of droughts in the lake and identify the contribution of the inflows of its five major tributaries and the Yangtze River.【Method】Based on daily hydrological data measured from 1953 to 2022, we identified hydrological drought events and their characteristics using the daily-variable threshold method. The XGBoost model was then used to investigate the relationship between the drought events and the inflows of the five tributaries: Ganjiang, Fuhe, Xinjiang, Raohe and Xiuhe, as well as the Yangtze River, and to assess the contribution of each river.【Result】The results showed a long-term decline in the average water level of Poyang Lake from 1953 to 2022, accompanied by diminishing spatial gradients across the lake. After 2003, the average drought duration increased by 18.4 days at Duchang Station and 20 days at Hukou Station, with their drought intensity increasing by a factor of 2.16 and 3.09, respectively. Spatially, the influence of the Yangtze River on the hydrological drought decreased from the mouth toward the interior regions, while the inflows from the five tributaries have become the primary drivers of drought events, particularly after 2003.【Conclusion】From a basin-wide perspective, optimizing the operation of the Three Gorges Dam, improving the regulation of water conservancy projects in the basin, and strengthening water conservation measures are critical for mitigating extreme hydrological droughts and maintaining ecosystem stability in the basin. |
| Key words: Poyang Lake; hydrological drought; XGBoost; drought evolution process; water level change |
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