黑河流域张掖段不同主体功能区水环境承载力评价

水环境承载能力是地区经济发展和生态环境保护的关键因素,为精准查明张掖市水环境承载力状况,基于各区县主体功能定位,从水资源、排放强度、水环境质量和水生态4个维度选取合理指标,构建了复合型水环境承载力评价指标体系,利用层次分析法和综合指数法评价了2018-2020年各区县水环境承载力,结果表明：2018年各区县评价指数介于63.9-79.4,民乐县和高台县为临界超载,其他县区不超载;2019年评价指数介于63.2-86.9,临泽县、民乐县和高台县为临界超载,其他县区不超载;2020年评价指数介于70.6-88.6,六县区均处于不超载状态,总体张掖市的水环境承载能力现状良好,且逐年提升。但临泽县、山丹县、民乐县和高台县刚脱离“临界超载”,“不超载”状态优势不存在,仍有较大提升空间。不同功能区4个指标对水环境承载力的影响程度排序情况有所差别,可依据评价结果提供的主要影响指标或压力指标信息,针对性采取改善提升不同功能区水环境承载力的措施。

Evaluations of water carrying capacity of different main functional areas in Zhangye City of the Heihe River Basin

Water environmental carrying capacity is a key factor for regional economic development and ecological environment protection. In order to ascertain accurately the water carrying capacity status of Zhangye City, this paper constructed an evaluation index system, it based on the main function positioning of each district and county, selected reasonable indexes from the four dimensions of water resources, discharge intensity, water environment and water ecology. Using analytic hierarchy process and comprehensive index method, the water carrying capacity of each district and county were evaluated, the results showed that the assessment index ranged from 63.9 to 79.4 in 2018, Minle county and Gaotai county are critical overloads, the other counties are not overloading; the assessment index ranged from 63.2 to 86.9 in 2019, Linze county and Minle county and Gaotai county are critical overloads, the other counties are not overloading; the assessment index ranged from 70.6 to 88.6 in 2020, all districts and counties are not overloading, which indicates that the water environment carrying capacity of Zhangye City is in good condition in general and has increased year by year. However, Linze County, Shandan County, Minle county and Gaotai County have just broken away from "critical overload", and the advantage of "no overload" state does not exist, and there is still much room for improvement.The ranking of the impact degree of the four indicators on water environment carrying capacity was different, considering the information of main impact indicators or pressure indicators provided by the evaluation results, this paper targeted measures to improve and enhance the water environment carrying capacity of different functional areas are put forward.