基于IHA/RVA法的近年来鄱阳湖生态水位变异研究

Study on Ecological Water Level Variation of Poyang Lake Based on IHA and RVA Method in Recent Years

湖泊水位是影响其生态功能正常发挥的重要因素,开展湖泊水位变异特征研究是正确认识湖泊水资源系统变化的前提。基于鄱阳湖区5个水文站1960~2014年的日水位监测数据,研究分析了近年来鄱阳湖水位年际变化的异常特征,并借鉴IHA/RVA法,定量揭示了2000~2014年鄱阳湖生态水位变异程度及其空间差异。结果表明:鄱阳湖水位近年来下降明显,湖口、星子和都昌站年平均水位自2009年以来呈现高度一致的变化特征,水位差几乎消失;2000~2014年鄱阳湖生态水位发生中度改变,整体改变度为38.86%;各水文站改变程度由高到低依次为都昌站、星子站、湖口站、康山站和棠荫站;主要水位指标体系中6和11月平均水位、最小3日和30日平均水位、年最高水位出现时间、年高水位频率和年水位减少率等指标变异程度均达到50%以上。近年来鄱阳湖水位异常及其空间差异与人为采砂导致的湖盆地形变化密切相关,这种水位变异已对湖泊湿地生态系统产生了众多不利影响。

Lake water level is a significant factors which essentially affects normal ecological function of lake. Proceeding researches and investigations specifically on characteristics of lake ecological water level alteration is prerequisite and imperative for enhancing understanding and comprehending about how lake water resources system changes during decades periods. Based on daily water level from year 1960 to year 2014 which acquired from monitoring data of 5 hydrological stations distributed over the region of Poyang Lake from 1960 to 2014, this current study first analyzed characteristics of inter-annual variation of Poyang Lake water level in recent years. On this basis then the IHA/RVA method was applied in this research to quantitative degree of ecological water level alteration and its corresponding spatial from time period of 2000-2014. Result shows that water level of the Poyang Lake has declined and recessed evidently in recent years. Specifically the annual average water level of Hukou, Xingzi and Duchang stations shares highly consistent and conformant alteration tendency, without apparent water level changes since 2009, and water level variation among those three stations has almost vanished from graph. In general speculate ecological water level variation of Poyang Lake during 2000-2014 is comparatively moderate which amounts to 38.86%.Among those 5 hydrological stations, Duchang station enjoys the highest changing, followed by Xingzi, Hukou, Kangshan and Tangyin station descendingly. Furthermore the variability of 5 major hydrological indicators which includes monthly water level(June and November), minimum 3 days and 30 days average water level, time of highest annual water level, frequency of high water level as well as annual water level reduction rate are all amount to over 50%. It is revealed that water level anomaly of Poyang Lake and its spatial variability during recent years may closely related to lake bottom morphology and topography alteration caused by sand mining. From those above analyses it is certainly illustrated that the current hydrological variation and alteration of Poyang Lake has already caused multiple adverse effects.