按照流域尺度从小到大,分别选择新安江流域、珠江流域和长江流域作为研究对象,通过实证分析发现上下游水环境库兹涅茨曲线遵从一定的演递规律,即上游地区往往会重复下游地区的曲线过程,但其发展阶段落后于下游地区。上下游的发展差异越大,这种规律表现得越明显。产生这一规律的主要原因是我国多数流域下游地区的经济发展水平一般高于上游地区,下游比上游更早地到达了环境库兹涅茨曲线的峰值,并具有了更强的环境保护能力。这一规律有助于深化对上游水资源保护的重要性的认识。国家和下游地区需要加强对上游欠缺的生态环境保护能力的支持和援助,降低上游水环境库兹涅茨曲线的峰值和曲率,从长远意义上减轻上游发展过程中对全流域生态环境产生的不利影响和生态保护代价。
Xin’an River Basin,Pearl River Basin,and the Yangtze River Basin were taken as study areas to make multi-scale analysis of Water Environmental Kuznets Curve(WEKC).Relationships between waste water discharge and per Capita GDP of provinces in a river basin were plotted in a figure.Through empirical analysis of WEKC in different regions from small to large scale watersheds,it could be discovered that the WEKC curves roughly follow a principle of repeating step by step from downstream to upstream districts.The curve experienced in the downstream usually reoccurs in the upstream later.The principle is evident especially when there are obvious disparities among development levels of the upstream and downstream.The main reason for this principle is possibly that economic development in downstream areas is generally earlier than the upstream.Consequently,the downstream areas usually possess stronger environmental protection capacity.So the downstream reaches the peak value of WEKC earlier than the upstream.The principle contributes to further understanding of the importance of upstream water resources protection.With background of West Development and Middle Rising Policies,this discovery also illuminates that upstream environmental protection capacity should be strengthened with supports of the country and downstream areas to promote entire and long term watershed protection.