鄱阳湖最小生态需水研究

基于鄱阳湖水文特征,建立鄱阳湖最小生态需水计算模型。研究将频率95%对应的水位为湖泊最低生态水位,根据鄱阳湖水位-面积关系曲线,得到对应的鄱阳湖湖区面积为1 503.9 km~2。通过折算将水面蒸发转换成湖面蒸发,得到湖面净蒸发量为483.09 mm,湖区年最小生态耗水为7.3亿m~3。采用计算河道内生态需水的方法计算出湖生态需水,运用最小月平均流量法、逐月最小流量法、Tennant法、90%保证率最枯月平均流量法和90%保证率逐月流量法等,对出湖河道生态需水进行计算,并用Tennant法对结果进行评价,通过分析比较得出90%保证率逐月流量法更适合确定鄱阳湖出湖最小生态流量,得到出湖最小生态需水为777.1亿m~3,最终得到鄱阳湖最小生态需水为784.4亿m~3。研究结果对鄱阳湖流域生态保育、水生态与水环境保护及水资源管理,提供重要科学依据。

Minimum Ecological Water Requirements of the Poyang Lake

Based on hydrological characteristics of the Poyang Lake basin, the model for computation of the minimum ecological water requirement is developed. The water level with frequency of 95% is defined as the minimum water level. The drainage area of the Poyang Lake basin is computed as 1503.9 km² based on the relations between water level and drainage area. The evaporation is decided to compute the lake water surface evaporation and the value is 483.09 mm and the minimum ecological water consumption is 0.73 billion m³. Moreover, methods of the instream ecological water requirements, the minimum monthly average streamflow, monthly minimum streamflow, Tennant method and 90% guaranteed minimum monthly average streamflow are used to compute the minimum ecological water requirement of the outflow from the Poyang Lake basin as 77.71 billion m³ and the minimum ecological water requirement of the Poyang Lake basin is 78.44 billion m³ The results of this study are of great importance for conservation of ecological environment, aquatic ecological environment and water resources management within the Poyang Lake basin.