鄱阳湖典型洪泛区水位-水面积、水位-水文连通性的非线性特征

Nonlinear Characteristics of Water Level-inundated Area and Water Level-hydrological Connectivity in Typical Floodplain Area of Poyang Lake

洪泛湿地水文过程是维持其生物多样性的重要前提,也是区域水资源调控的重要基础。湖泊洪泛湿地的水文迟滞性是揭示湖泊水文过程及水量平衡的重要内容。论文以鄱阳湖南矶湿地及毗邻湖区为研究区,应用湖泊二维水动力数值模型、地统计学分析和数值积分等技术方法,探讨分析了洪泛湿地的水位-水面积与水位-水文连通性的非线性迟滞特征。研究结果表明,①鄱阳湖典型洪泛湿地存在季节尺度和涨水-退水事件尺度上的水文迟滞性;②水文迟滞程度年际差异显著,丰水年的水文迟滞性程度强于平水年和枯水年,涨水期的水文迟滞性程度强于退水期。地貌结构和洪水蓄排是引起水文迟滞性的主要原因之一,尤其是鄱阳湖南部众多的蝶形湖可能加剧洪泛湿地水文迟滞程度。水位-水面积、水位-水文连通性的非线性响应关系表明,洪泛湿地水资源管理和生态水文研究亟须加强湿地水文观测,揭示湿地水文连通特征。研究结果可为洪泛水文理论和湿地生态保护和管理提供重要依据和科学参考。

The hydrological process of flooded wetlands is an important basis for maintaining its biodiversity and water resources regulation.The hydrological hysteresis of lake flooded wetlands is an important part of revealing lake hydrological process and water balance.This paper takes the Nanji Wetland and its adjacent lake areas as the research area,and uses the two-dimensional hydrodynamic numerical model of lake flooding,geostatistical analysis and numerical integration to discuss and analyze the relationship of water level,inundated area and hydrological connectivity.The results show that the typical flooded wetland of Poyang Lake has hydrological lag on the seasonal scale and on the scale of rising and falling events.What’s more,the degree of hydrological lag has significant interannual differences where the degree of hydrological hysteresis is stronger in wet years than normal and dry years.It is also found that the hydrological hysteresis is obvious in the rising period other than the recession period.Landform structure and flood storage and drainage are one of the main causes of hydrological lag,especially the numerous sub-lakes in the south of Poyang Lake may aggravate the hydrological lag of flooded wetlands.The nonlinear response relationship of water level,inundated area and hydrological connectivity indicates that it is urgent to strengthen wetland hydrological observation and reveal the characteristics of wetland hydrological connectivity in flood wetland water resources management and eco-hydrological research.The research results can provide an important basis and scientific reference for floodplain hydrology theory and wetland ecological protection and management.