中文摘要：

流域水资源开发阈值是流域水资源合理利用的基础和流域生态系统健康的保证。随着水资源短缺引起的问题日益突出，人们对水资源开发阈值的认识也在不断加深，从最初的“水资源总量”、“可利用量”和“可供水量”等．到考虑生态需水和水质保护的水资源可利用量。本文在这些理念的基础上．提出一种新的流域水资源开发阈值及其计算模型，即考虑水资源量、不可利用的洪水量、被污染水量、生态需水量及重复计算水量，综合计算流域水资源开发阈值。黄河流域作为我国水资源严重短缺地区。水资源开发面临严峻挑战。以黄河流域为例，运用该阈值模型对黄河流域水资源开发阈值进行初步计算．得到开发阈值多年平均约为238亿m^3．占黄河天然径流量的40％左右．符合国际公认的流域水资源开发标准。

英文摘要：

Threshold of water resources exploitation is the basis for reasonable use of water resources and guarantee of ecosystem health in a basin. With the shortage of water resources becoming increasingly obvious a problem, the understandings on threshold of water resources exploitation are more and more deep, developing from the concept of ＂total water resources＂, ＂useful water resources＂ and ＂available water resources＂ to available water quantity considering the ecological water demand and water quality protection. In the paper, based on the concepts on water resource use, a new threshold theory and model of water resource exploitation in a basin is developed, which includes runoff, non-useful flood, water pollution, ecological water demand and repetitive calculation of water quantity. With the model, the threshold of water resource exploitation in a basin can be obtained. The Yellow River Basin is one of the serious water shortage regions in China, and it is at the risk of serious challenges of water scarcity. As one example, the threshold of water resource exploitation in the Yellow River Basin is preliminarily calculated by the model. The result shows that the average threshold is 23.8 billion m^3, accounting for about 40% of the total natural runoff, which is accordant with the internationally recognized standards on water resource exploitation within a basin. The threshold of water resource exploitation can be increased by the ways of water diversion, decreasing water pollution, increasing pondage of reservoirs and increasing water use efficiency.