基于灰水足迹的中国城市水资源可持续利用综合评价

随着城市化的快速发展,中国城市水资源面临着水资源短缺与水环境恶化等挑战,因此加强城市水资源可持续利用对于中国可持续发展具有重要意义。基于灰水足迹核算对2016年中国地级市水资源可持续利用情况进行综合评价。研究结果表明：（1）中国城市灰水足迹水平差异大,平均值为23.40×10⁸ m³,主要集中在20.00×10⁸ m³以下。中国城市农业源灰水足迹比例占比主要在70%以上,工业源比例占比主要在20%以下,而生活源比例占比在40%以下;（2）全国灰水经济生产率在12.45-857.31元/m³范围内,地区差异明显。33%城市灰水足迹荷载系数均大于1,全国地级市灰水足迹荷载系数平均值为1.16,城市水资源利用已对水环境产生污染压力,用水不可持续;（3）城市水资源开发率与灰水足迹荷载系数呈一定程度的正相关关系,说明了城市发展对水资源利用的"量"和"质"的压力作用具有一定的协同关系;（4）水资源可持续利用程度呈现大型城市 > 特大型城市 > 超大型城市 > 中小型城市,城市发展一定程度上有助于水资源的可持续利用,但发展规模过大可能会造成用水高产而护水低效的现象。因地制宜的实行水资源循环经济发展模式以及适时纳入灰水足迹核算与管理体系,是当前城市化大背景下实现水资源可持续利用的重要途径。

Integrated assessment of sustainability in urban water resources utilization in China based on grey water footprint

With rapid urbanization in China, urban water resource utilization is facing up to growing challenges brought by the water shortage and pollution. Thus, it is greatly significant to strengthen the sustainability of urban water resource utilization for China''s sustainable development. The indicator of grey water footprint, which provided a metric measurement for the integrated assessment of water resource scarcity in terms of water pollution, was applied in assessing the sustainability in water resource utilization of the prefecture-level cities in China in 2016 (the data of country-level city, as well as Hongkong and Macao special administrative region and Taiwan region was not included). The results showed that (1) the urban grey water footprints of prefecture-level cities were significantly different with an average of 23.40×10⁸ m³, most of which were less than 20.00×10⁸ m³. The percentages of agricultural grey water footprints accounted for more than 70% in majority cities, and those of industrial and residential grey water footprints accounted for lower than 20% and 40%, respectively. (2) The economic productivity of urban grey water ranged from 12.45-857.31 yuan/m³ with significantly regional differences. The cities under great water environmental pressure with grey water footprint load coefficients higher than 1 accounted for 33% of overall cities assessed. The average coefficient of the assessed cities was 1.16, indicating that current urban water resource utilization was unsustainable and had negative impacts on water environment. (3) This study discussed the relationships between urban water resource utilization and protection, and found that there exited synergic relationships between urban water resource exploitation rates and grey water footprint load coefficients in terms of the impacts of urbanization on the quantity and quality of urban water resource. (4) The degrees of sustainable water resource utilization decreased in the order:big city > megapolis > megacity > small and medium city. Urban development to some extent contributes to the sustainability of water resource utilization, but excessive sprawl of economy and population sizes may degrade environmental-friendly water economy, which inclines to balance the achievements of economic efficiency and environmental protection in water resource utilization. Finally, suggestions for sustainable water resource management are summarized. Taking advantage of regional geography, promoting the water resource circulation economy, and incorporating the grey water footprint accounting and management system are important ways to achieve sustainable water resource utilization under the background of rapid urbanization, contributing to nationally fulfilling the 17 Sustainable Development Goals stipulated by United Nations 2030 Agenda, in terms of urban water resource utilization.