2022年长江中下游干流河道输沙与冲淤变化特点

Characteristics of sediment transport and erosion-deposition changes in the middle and lower reaches of the Changjiang River in 2022

  • 摘要: 2022年长江流域遭遇了汛期反枯的极端水文气象条件,导致长江中下游的水位降至有实测资料记录以来的同期最低,该极端水文情势使长江中下游河道冲淤变化出现了新特征。基于详细实测水沙监测及固定断面资料,对2022年极端水文气象条件下长江中下游干流河道输沙的冲淤变化特点进行深入分析。结果表明:1—6月份长江中下游各测站输沙量有增有减,总体上输沙量保持相对稳定;7—12月份各测站输沙量均出现了大幅下降,宜昌至九江河段通过输沙量法计算得知冲刷的泥沙总量为2 391 万t,通过断面法计算得知湖口至江阴河段泥沙淤积量为4 657 万m3(湖口至大通冲刷量为1 211 万m3,大通至江阴淤积量为5 868 万m3),江阴以下河段冲刷量为6 335 万m3。上游来流减少和长江口潮位的影响是造成湖口至江阴河段淤积的主要原因。研究成果可为进一步探索长江中下游河道冲淤变化规律、预测未来的冲淤趋势提供重要参考。

     

    Abstract: In 2022, the Changjiang River Basin experienced an extreme hydrometeorological event characterized by drought conditions during the flood season, causing water levels in the middle and lower reaches of the Changjiang River to drop to the lowest on record for the same period. This extreme hydrological situation led to new patterns of erosion and deposition changes in these river reaches. Based on detailed monitoring data of water and sediment, as well as fixed cross-sectional data, this study conducted an in-depth analysis of the sediment transport and erosion-deposition characteristics in the main channel of the middle and lower Changjiang River under these extreme conditions in 2022. The results showed that sediment transport varied between stations from January to June, with overall stability. However, from July to December, there was a significant decline in sediment transport at all stations. Calculations based on sediment transport methods revealed that 23.91 million tonnes of sediment were eroded from the Yichang to Jiujiang section, while cross-sectional methods indicated that the Hukou to Jiangyin section experienced a deposition of 46.57 million cubic meters of sediment (with 12.11 million cubic meters of erosion from Hukou to Datong, and 58.68 million cubic meters of deposition from Datong to Jiangyin). Additionally, 63.35 million cubic meters of sediment were eroded downstream of Jiangyin. Reduced upstream inflows and tidal effects in the Changjiang River estuary were the primary causes of deposition in the Hukou to Jiangyin section. These findings provide crucial insights for further understanding the patterns of erosion and deposition in the middle and lower Changjiang River, and offer valuable references for predicting future trends.

     

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