河道生态环境分区需水量的计算方法与实例分析

为真实反映流域各区间的河道生态环境需水量差异 ,同时解决流域上下游河道生态环境需水量的重复计算问题 ,提出了河道生态环境分区需水量的概念 ,对流域分区、河道功能确定和河道生态环境分区需水量计算方法进行了研究 .以黄河流域为例进行了实证分析 .结果表明 ,黄河流域的河道需水分区需水量差异显著 ,黄河下游区间的河道分区需水量最大 ,为 14 8 93× 10 8m3·a- 1 ,上游兰州—河口干流区间最小 ,为-5 0 12× 10 8m3·a- 1 ,龙羊峡—兰州干流区间和黄河下游区间河道分区需水量超过区间的自产水资源量 ,需要其它区间的水量补充 ,才能维持其河道的生态环境功能 .黄河流域的河道分区需水量之和为 2 3 0 6× 10 8m3·a- 1 ,约为流域地表水资源量的 3 9% ,说明黄河流域地表水资源的最大利用率应低于 61% .

Computing method of divisional ecological and environmental water requirement for river channel and its application to the Yellow River Basin

Because the ecological and environmental water requirement for river channel is calculated individually in every division, the repeated amount between ecological and environmental water requirements of river channel existed in neighboring reaches. For identifying actual ecological and environmental water requirement for river channel for every division, the concept of the divisional ecological and environmental water requirement of river channel is put forward, and the methods to plot the division of watershed, designate the ecological function of river and calculate divisional ecological and environmental water requirement of river channel are studied. The Yellow River is studied as an example, and the minimum ecological and environmental water requirement of river channel and corresponding divisional ecological and environmental water requirement of river channel for divisions of the Yellow River Basin are calculated separately. The results indicate that the divisional ecological and environmental water requirement of the Lower Section of the Yellow River is the maximum among all division, which is about 14.893 billion m~3 per year. And the regional ecological and environmental water requirement of river channel of Lanzhou-hekou Section is minimum, which is about -5.012 billion m~3 per year. The sum of divisional ecological and environmental water requirement of river channel of the Yellow River Basin is 23.06 billion m~3 per year, which is about the 39 percent of surface water resources of the Yellow River Basin. It means that the maximum utilization ration of surface water resources should be below 61% in the Yellow River Basin. The divisional ecological and environmental water requirement for river channel of the Lower Section of the Yellow River and Longyangxia-lanzhou Section cannot be met by the surface water resources produced in its division, and should be supplemented from other divisions through the rational allocating planning of watershed water resources. So the results can offer support for rational planning of water resources of the Yellow River Basin.