基于河流健康及国际法的跨境水分配关键指标及阈值

Key indicators and the thresholds of trans-boundary water allocation based on river health and international treaties

基于前期研究中获得的8个河流健康主要评价指标、3个主要跨境水分配指标的结果以及指标之间的相关性,确定了河流健康和跨境水分配的关键指标:多年平均水量、最大取用水量和最小维持水量。跟踪查询《国际淡水条约数据库》内1864-2002年应用3个关键指标的38个国际条约及其所涉及28条国际河流的主要水文信息,通过对条约中水分配指标的标准化计算和分析,得到各指标阈值及其区域性特征:1最小维持水量指标得到普遍应用,其次是多年平均水量指标,而最大取用水量指标应用率明显低于前两个指标。2应用多年平均水量指标,在界河上基本确定了平均分配方案,阈值为50%;"内河"属性支流的阈值为100%;跨境河流上产生了较多的差额分配方案和较多的上游国用水多于下游国的方案。3最小维持水量指标,其应用有从发达地区向发展中地区扩展、从保证用水向维持生态用水发展的特点;当该指标在跨境和界河的河流尺度上用于保证供水时,该指标阈值平均分别为41.7%和50%,且流域国家实力对其影响极为明显,而在跨境河流河段尺度上阈值平均为36.1%;用于维持河道生态水量时,阈值平均为14.7%,并有逐步增长的趋势。

In the paper,according to the revealed major indicators on river health assessment and of transboundary water allocation in the preliminary studies,after the correlations among them were analyzed,the key indicators of transboundary water allocation and of healthy riverwere finally confirmed,as：mean annual runoff,maximum water intake,and minimum maintained water volume.Based on 38 international treaties related to water allocation in 1864-2002 adopting the 3 key indicators,some key hydrological data of the 28 rivers covered by the treaties from various publications were looked up,the values of the 3 key indicators were standardized and calculated,and the thresholds and the regional characteristics of them were analyzed.The results were as follows：（1） Among the 3 key indicators,＂minimum maintained water volume＂ was most widely adopted,and ＂maximum water intake＂ was the one with the lowest adoption.（2） From the adoption of mean annual runoff,for the frontier rivers,the basic scheme of water allocation was equal allocation,and the threshold was 50%;for the tributary,which was totally within one country,the threshold was 100%;for transboundary rivers,there were more schemes with a different allocation,and more ones with a greater share for an upstream country.（3） As for the indicator of ＂minimum maintained water volume＂,its adoption showed the extending tendencies from the developed regions to the developing ones,and from maintaining water supply for downstream countries to keeping ecological water demand.When it was used for maintaining water supply,at the river scale,the average thresholds were 41.7% on transboundary rivers and 50% on frontier ones,respectively,which were obviously affected by riparian countries＇ strength,while at the reach scale,the average threshold was 36.1% on transboundary rivers.When it was used for keeping water flow in watercourse,the average value of the thresholds was 14.7%,with an increasing tendency.