鄱阳湖区沉积物粒度特征与洪涝灾害关系研究

根据在鄱阳湖大汊湖采集的200 cm土壤沉积物剖面样品(DCL剖面),基于¹⁴C 测年建立时间标尺和粒度组分等指标,并结合历史资料,对鄱阳湖区300年来的洪涝灾害进行了分析.结果表明,鄱阳湖区300年来洪涝灾害可分为3个阶段:1680—1749 aB.P.鄱阳湖区气候变化不明显,洪涝灾害少而稳定,大洪水年较少; 1750—1890 aB.P.鄱阳湖区气候变化较明显,洪涝灾害频繁; 1891 aB.P.至今鄱阳湖地区气候变化显著,洪涝灾害频繁,并且大洪涝年份多.鄱阳湖区300年来的干湿状况可划分为干燥—湿润—干燥.

The Study on the Relationship of Grain-Size Characteristics and Flood Disaster in Poyang Lake Region

The sediment granularity of Lake Dacha through collecting samples from Lake Dacha is analysed,and the document of flood disaster taking place in recent 300 years in Poyang Lake region is gathered,in which about 11 flood events including one happened in 1683 are found,through testing time sequence of section establishment by AMS-¹⁴C test.According to the result of granularity test,flood disasters happening in recent 300 years are analyzed combined with analysis result of historic data.The result shows that the flood disasters in Poyang Lake are divided into three stages.The first stage starts from 1680 to 1749.In this stage,there were not too many climate changes in Poyang Lake region,the flood disaster was few and stable.The second stage is from 1750 to 1890.In this stage,climate changed a lot in Poyang region.There were flood disasters happening frequently.However,compared to the first stage,situation was not that bad.The third stage is from 1891 to now.In this stage,climate in Poyang Lake region has had the biggest change.Flood disasters happened quite frequently.Based on analysis of granularity average and index of drought and flood,dry-wet condition in Poyang Lake over recent 300 years can be divided into three processes from dry to wet then to dry.