基于水量与水质的太湖流域水生态服务供需关系及多情景评估

耦合水量供给与水质净化的水生态服务供需关系的多尺度空间量化评估,有助于刻画和识别丰水区水质性缺水问题,并丰富水生态服务研究。在构建水量供给和水质净化服务供需评估方法的基础上,利用空间分析方法在现状情景基础上分别设置提升用水效率、改善土地管理方式和优化土地利用空间配置三种优化情景,并在栅格、子流域和县域三个尺度上开展基于水量供给和水质净化的水生态服务供需关系的定量评估,分别探讨了不同情景不同尺度下的水生态服务供需变化、空间响应及其机制特征。研究结果表明：(1)太湖流域的水量供需状况显著优于水质供需状况,节水能够有效改善流域内的水量赤字,而减量施肥和优化土地利用配置能够显著改善流域内的水质赤字。(2)多尺度的水量供给与水质净化服务供需解析,有助于精准识别不同尺度下亟需治理的关键区域。(3)水量赤字区主要集中在建设用地分布区域,耕地仍是引致水质赤字的主要原因,但随着尺度的逐渐增大,水质赤字区的建设用地面积也在不断增加。(4)优化土地利用结构方案是解决水质性缺水的最有效方法,但需要突破现有政策尤其是耕地保护政策的刚性约束,故耦合提升用水效率等方法是当前治理太湖流域“水质性缺水”问题首选措施。

Supply and demand relationship and multi-scenario assessment of water ecological services related water quantity and quality in Taihu Lake Basin

It is essential to conduct supply and demand assessment of water ecological services across multiple spatial scales by integrating water quantity and quality for identifying water shortage issues caused by water pollution in humid regions. This study developed a comprehensive model that integrated water quantity and quality for quantifying the supply-demand relationships of water ecological services for the Taihu Lake Basin (TLB). This study also constructed three optimized scenarios (Water Efficiency Improvement, Fertilization Reduction, and Land Use Structure Optimization) to explore the spatial variations and key driving factors of water resources supply and demand on the grid, sub-basin, and county levels. We got the following conclusions:(1) The TLB was sufficient in water quantity, but it was deficient in water quality. Water efficiency improvement significantly reduced the demand for water resources in the TLB. Fertilization reduction and land use optimization greatly improved water quality. (2) The supply and demand assessment of water ecological services across the three spatial scales could help in identifying key areas for promoting sustainable water use in the TLB. (3) Urban land was primarily located in the regions with deficient water quantity. In comparison, croplands dominated the regions with deficient water quality, while these regions of deficient water quality were also comprised of large areas of urban land when assessed at the county level. (4) Land use optimization such as grain for green and riparian conservation was the most effective in improving water quality for the TLB, but it was at the huge cost of cropland losses. Therefore, coupling other optimization ways such as water efficiency improvement that would be the best measurement for solving pollution-caused water shortage issues in the TLB.