多元驱动下水生态承载力评价方法与应用——以京津冀地区为例

摘要

水生态承载力通常是指在维持水生态系统自身及其支持系统健康的前提下,基于一定的生态保护和承载目标,自然水生态系统所能支撑的人类活动的阈值.从水生态承载力的概念出发,基于水资源、水环境和社会经济等要素,筛选出水资源利用率、污水处理率、万元GDP用水量等16个指标对水生态承载力评价的多元耦合作用进行分析,量化驱动因子与水生态承载力之间的关联度,建立了具有多元驱动功能的粒子群引力搜索算法-投影追踪(PSOGSA-PP)水生态承载力评价模型.并以京津冀地区为例,解析了区域水资源和水环境的生态效益,以及经济社会效益最大化的内在驱动,评价了水生态承载力并阐明其影响因素.进一步设定不同时间段的水生态承载力情景方案,通过具有较高寻优精度和较好算法执行能力的粒子群引力搜索算法,利用最佳投影方向(a)分别计算分级标准阈值的投影值z'(i)和评价实例的投影值z”(i),基于投影值z'(i)构造水生态承载力评价等级,实现了水生态承载力的分级评价,结果表明,在多元因子共同驱动下,2008年-2030年京津冀所属13个地区的水生态承载力在波动中呈好转趋势,逐步由Ⅳ级(超载)、Ⅴ级(严重超载)向趋于Ⅱ级(比较理想)状态的演变,张家口市始终保持着Ⅱ级水平,并在2030年达到Ⅰ级(理想)的临界值.研究成果将为京津冀一体化的水资源开发利用与水源生态涵养提供重要的决策支持.%Water ecological carrying capacity refers to the degree that natural aquatic ecosystems can support human activities under certain conservation goals,while maintaining ecosystem quality.To explore this concept,which is based on water resources,environmental conditions,and socioeconomic factors,16 indicators were selected to analyze the multivariate coupling effect of water ecological carrying capacity and to quantify correlations between this effect and related driving factors.A particle swarm optimization gravitational search algorithm-projection pursuit (PSOGSA-PP) model with a function of multiple drivers was established to evaluate water ecological carrying capacity.The Beijing-Tianjin-Ji (Hebei Province) region was chosen as a case study for analyzing the drivers of ecological benefits of regional water resources and water quality and for maximizing the associated economic and social benefits,as well as to evaluate water canying capacity and impact factors.Scenarios were developed based on carrying capacities during different periods,and water ecological carrying capacity evaluation levels were established using PSOGSAs and the optimal projection direction (a),the classification standard threshold projectionz'(i),and the projection value of evaluation instancez"(i).Water carrying capacity exhibited an improving trend,from level Ⅳ (overload) and level Ⅴ (extensive-overload) to level Ⅱ (ideal),for 13 cities in the Beijing-Tianjin-Hebei region from 2008 to 2030;projections indicated,for instance,that Zhangjiakou City would remain at level Ⅱ for the most of the period,and attain level Ⅰ (ideal) by 2030.Our results offer support for the exploitation and utilization of water resources,as well as the protection of aquatic eco-systems,in the Beijing-Tianjin-Hebei region in the future.