基于SWAT的沁河流域水压力指数计算及生态脆弱性分析

Ecological Vulnerability Analysis of the Qinhe River Basin Based on SWAT and Water Stress Index

生态脆弱性是综合反映流域生态系统健康水平的重要属性,而水资源是维持流域生态系统健康和可持续发展的关键因素。因此,从水资源领域评估流域生态脆弱性并分析其时空变化特征对于应对流域水资源短缺压力和改善流域生态系统健康水平具有重要的研究价值。以沁河流域为研究对象,构建流域SWAT模型,引入水压力计算公式,从蒸散发量的角度,量化分析沁河流域2010-2016年生态脆弱性的时间变化和空间分布特征。结果表明:①SWAT模型经过率定与验证后,纳什系数E NS和相关系数R 2均符合模型精度标准,表明该模型在沁河流域具有良好的适用性。②流域年际水压力指数值随时间递减,表明沁河流域生态脆弱性及生态系统状态逐年好转,蒸散发量是主要影响因素。③流域水压力指数年内变化大,本年度12月到次年度2月的生态脆弱性较强;结合相关研究结果,认为降水和冰雪天气是主要影响因素。④流域整体生态脆弱性状况逐年改善,但流域内部生态脆弱性空间差异化呈现扩大趋势。

Ecological vulnerability is an important attribute that integrates the level of health of watershed ecosystems,and water resources are the key factor in maintaining the health and sustainability of watershed ecosystems.Therefore,assessing the ecological vulnerability of watersheds from the field of water resources and analyzing their spatial and temporal variability characteristics are of great research value for coping with the pressure of water scarcity in watersheds and improving the health of watershed ecosystems.This paper takes the Qinhe River Basin as a research object,constructs the SWAT model of the basin,introduces the water stress calculation formula,and quantifies the temporal changes and spatial distribution characteristics of ecological vulnerability in the Qinhe River Basin from 2010 to 2016 from the perspective of evapotranspiration.The results show that:①After the rate determination and validation of the SWAT model,E NS and R 2 meet the model′s requirements,indicating that the model has good applicability in the Qinhe River Basin.②The interannual water stress index of the basin decreases with time,which indicates that the ecological vulnerability and ecosystem status of the Qinhe River Basin are improving year by year,and evapotranspiration is the main influencing factor.③The basin′s water stress index varies greatly within the year,and ecological vulnerability is higher from December in this year to February in the next year;combined with the results of related studies,precipitation and snow and ice weather are considered to be the main influencing factors.④The overall ecological vulnerability status of the basin has been improved year by year,but the spatial differentiation of ecological vulnerability within the basin shows an expanding trend.