延河流域水供给服务供需平衡与服务流研究

水供给服务的供需定量评估与空间制图是当前研究的核心与前沿议题,然而耦合人类需求与自然过程进行供需时空关联分析和服务流模拟仍需进一步加强。以延河流域为研究区,基于GIS手段和SWAT模型,融合多源数据构建了水供给服务供需平衡与空间流动模型,从子流域尺度探究了延河流域水供给服务的供需空间匹配特征与流动规律,明确流域供给区和受益区的空间范围与流量。研究结果表明:1)2005—2015年延河流域水供给量先增多后减少,水需求量则逐年增多,供需平衡状况在逐年恶化。到2015年,流域的水资源安全指数(Freshwater Security Index,FSI)仅为0.095。2)延河流域水供给服务的供给与需求在空间分布上呈现显著的不匹配特征,尤其是位于延河中游的延安市区及周边地区,水资源供需矛盾突出。3)在水供给服务流研究的框架下,本文明确了流域内4个主要受益区的空间范围及其接受的相应上游子流域(供给区)提供的服务流量,分别为安塞城区、延安市区、青化砭镇、延长县城区及其附近城镇。本评估模型与研究结果不仅可以为实现延河流域水资源的合理配置和保障流域用水安全提供科学依据,也可以为其他流域的水资源管理提供参考。

Quantification and simulation of supply, demand and flow of water provision service in the Yanhe watershed, China

Quantitative assessment and spatial mapping of supply and demand of water provision service are frontier issues of current research. However, the spatial-temporal connections of supply and demand and the space flow of water provision service still need to be further strengthened. In this study, the Yanhe watershed was selected as the study area. Based on GIS technology and SWAT model, the supply-demand balance and spatial flow models of the water provision service were proposed by integrating multi-source data. According to the proposed methods, the spatial matching characteristics and flow laws of the water provision service in Yanhe watershed were explored at the sub-basin scale. Moreover, the spatial scope of the provisioning and benefitting areas of the basin were determined. The results showed that, from 2005 to 2015, the water supply first increased and then decreased, while the water demand increased year by year. The supply-demand balance of the water provision service deteriorated year by year, and the freshwater security index (FSI) was reported to be 0.095 in 2015. Significant mismatch in the spatial distribution was observed in terms of the supply and demand of the water provision service in Yanhe watershed. This was particularly evident in urban area and surrounding areas of Yan''an city, which is located in the middle reaches of Yanhe watershed, where the contradiction between supply and demand of the water resources was prominent. Under the framework of the water provision service flow, the study defined the spatial scope of the four main benefiting areas within the water basin and the service flow provided by the corresponding upstream sub-basins (provisioning areas), which included the urban areas of Ansai county and Yan''an city, Qinghuabian town, and Yanchang county. The framework and results presented in the study not only provide a scientific basis for realizing the rational allocation of water resources and ensuring water security in the Yanhe River basin, but also provide a reference for the management of water resources in other basins.