鄱阳湖水位空间差异及其对湿地水文分析的影响

Spatial difference of water stage and its impact upon wetland hydrological analysis in Poyang Lake

大型湖泊受支流人流及湖底特性、风浪变化等因素的综合影响,其内部不同区域的水位存住空间差异.水利工程设计、湿地水文调控分析中常以单个水文站点的水位代表整个湖泊的水位状况.受五河及长江水量变化规律的综合影响,其枯水水位空间差异较大.在洲滩湿地水文调控分析中,代表水文站的选择尤为重要.目前湿地水文分析中常采用湖口、星子两站作为鄱阳湖的代表站,但站点选择却均缺乏科学的数据分析.本文结合56年来鄱阳湖湖区7个水位站点的监测数据及站点的空间位置信息,分析了湖区各水文站点间的水位差异及水位比降.结果显示棠荫站作为鄱阳湖湿地水文分析的代表站较合适.结合鄱阳湖湖底地形数据探讨了相对于棠荫水位,以湖口或星子水位来模拟鄱阳湖洲滩湿地面积的差异,以及可能产生的潜在影响.

The topography and wind make the water stage not the same at different sites in the great scale lake. Observation of single gauge station among the lake often is used to represent the water surface height of the whole lake in the water engineering projects design and wetland hydrological analysis. The water stage of any gauge could depict the lake surface well, if the spatial difference of water stages among the lake is not remarkable. As the largest freshwater lake, Poyang Lake has an uneven water surface, especially in the low water period, for its complex hydrological environment caused by its five tributary and Yangtze River. So it is very important to select the representative gauge in the wetland hydrological analysis of the lake. The 56-year observation series of sevengauges in Poyang Lake are compared according the water stage difference among them and their location. The average water stage discrepancy and slope of Tangyin both are smallest in the seven gauges, which make it as the best representative station. Then the wetland inundation simulation results based on Hukou, Xingzi, which are two often used representative stations, compared with that base on Tangyin. Great area differences of simulation results highlight the importance of the representative gauge station selection.