长江经济带沿线城市水资源绿色效率及节水减排潜力时空演变

Spatial-temporal Evolution of Water Resources Green Efficiency and Potential of Water-saving and Emission-abating in Cities Along Yangtze River Economic Belt

准确测算长江经济带沿线城市水资源绿色效率,对长江经济带沿线城市的水资源合理利用和绿色发展建设具有重要意义。运用SE-SBM模型(Super-Efficiency Slacks-Based Model)测度2010~2019年长江经济带沿线45个城市水资源绿色效率,结合泰尔指数分解探究其水资源绿色效率地区差异的形成根源,并采用ML指数方法(Malmquist-Luenberger)挖掘水资源绿色效率变化的内在原因;进而,利用水资源投入和水污染物产出的实际值与最优值的差异测算长江经济带沿线45个城市的节水减排潜力。结果显示:(1)研究期内长江经济带沿线45个城市有77.8%的城市水资源绿色效率处于无效率,水资源绿色效率空间分布呈现为长江经济带下游>上游>中游;(2)2010~2019年长江经济带沿线45个城市水资源绿色效率整体处于上升阶段,但有昭通、丽江、攀枝花、贵阳、铜陵、湖州、绍兴、舟山和鄂州等9个沿线城市水资源绿色效率处于下降阶段,受到不同程度的纯技术效率、规模效率和技术进步变化的影响;(3)将节水潜力、污水减排潜力和工业废水减排潜力值分别划分为“低、中和高”3个区间段,并将沿线45个城市分为“三高、二高、一高、中等和三低”5种类型,其中岳阳、马鞍山、黄石和荆州等4个城市属于“三高”类型;在空间格局上,节水减排潜力“三低”类型的城市呈现出“大连片,小散落”的集聚形势。基于以上研究结果,本研究可为促进长江经济带沿线城市水资源合理开发利用,实现区域高质量绿色发展提供对策。

Accurately measuring the green efficiency of water resources in cities along the Yangtze River Economic Belt is of great significance to the rational utilization of water resources and green development and construction of cities along the Yangtze River Economic Belt.The SE-SBM model(Super-Efficiency Slacks-Based Model)is used to measure the green efficiency of water resources in 45 cities along the Yangtze River Economic Belt from 2010 to 2019.Combined with the decomposition of Theil index,the root causes of regional differences in green efficiency of water resources are explored,and the ML index method(Malmquist-Luenberger)is used to explore the internal causes of changes in green efficiency of water resources;Furthermore,the difference between the actual value and the optimal value of water resources input and water pollutant output is used to calculate the water-saving and emission reduction potential of 45 cities along the Yangtze River Economic Belt.The results show that:First,during the study period,77.8%of the 45 cities along the Yangtze River Economic Belt were inefficient in the green efficiency of urban water resources,and the spatial distribution of green efficiency of water resources shows that the lower reaches of the Yangtze River Economic Belt>the upper reaches>the middle reaches;Second,from 2010 to 2019,the green efficiency of water resources in 45 cities along the Yangtze River Economic Belt was on the rise,but the green efficiency of water resources in 9 cities along the Yangtze River Economic Belt,including Zhaotong,Lijiang,Panzhihua,Guiyang,Tongling,Huzhou,Shaoxing,Zhoushan and Ezhou,was on the decline,which was affected by the changes of pure technical efficiency,scale efficiency and technological progress to varying degrees;Third,the water-saving potential,sewage emission reduction potential and industrial wastewater emission reduction potential are divided into three sections of“low,medium and high”,and 45 cities along the line are divided into five types of“three high,two high,one high,medium and three low”,of which Yueyang,Ma’anshan,Huangshi and Jingzhou belong to the“three high”type;In terms of spatial pattern,cities with“three low”types of water-saving and emission reduction potential show the agglomeration trend of“large settlement,small scattered”.Based on the above research results,this study can provide countermeasures for promoting the rational development and utilization of urban water resources along the Yangtze River Economic Belt and realizing regional high-quality green development.