基于网络分析的水网可达性评估

Accessibility evaluation of water networks based on network analysis

【目的】为探究水资源可达性的空间格局,促进优化水资源配置,科学规划水系布局,【方法】提出一种基于网络特性和取水成本的水网可达性计算方法。运用网络分析工具sDNA计算网络可达性指标,以CRITIC法计算网络分析指标权重,加权求和得到水网网络可达性,然后通过核密度估计进行空间拓展;综合考虑地形、土地利用、道路因素,制作研究区的成本阻力栅格数据,水网网络可达性减去累计成本阻力,以此评估水网的可达性。【结果】研究区的平均可达性为0.31,标准差为0.04,变异系数为0.13。当河网是偏自然状态水系时,可达性呈现出树枝状分布,从主河道到支流逐渐减弱,且随着远离河道而减弱。在地形较为平坦、人类活动频繁、人工渠道发达的区域,一些江河交汇处将出现水网可达性较高的密集区域,例如汉江中游、长江中游、太湖流域、里下河流域、黄淮海平原、渭河平原。【结论】结果表明,从网络分析的角度出发,将水网视为一个拓扑网络来计算水网的可达性,实现了在大尺度区域的应用。同时考虑了取水成本和阻力对局部可达性的影响,从而增加了可达性结果的准确性,为实现精细化的水资源管理提供了重要的依据。

[Objective]To investigate the spatial pattern of water resources accessibility,facilitate the optimization of water resources allocation,and scientifically plan the water system layout,[Methods]a calculation method of water network accessibility based on network characteristics and water intake cost is proposed.The network analysis tool sDNA is utilized to calculate network accessibility indexes,while the weight of each index is determined using CRITIC method.A weighted sum approach is employed to obtain an overall assessment of network accessibility,and then the spatial expansion is carried out by kernel density estimation.Based on the comprehensive consideration of terrain,land use and road factors,the pan-basin cost resistance grid data is made,and the network accessibility of water network subtracts the cumulative cost resistance,so as to evaluate the accessibility of water network.[Results]The mean accessibility of the study area is 0.31,the standard deviation is 0.04,and the coefficient of variation is 0.13.When the river network is a more natural water system,accessibility presents a dendritic distribution,and gradually weakens from the main river to the tributary,and decreases as it moves away from the river.In areas with relatively flat terrain,frequent human activities and developed artificial channels,dense areas with high water network accessibility will appear at some river conjunctions,such as the middle reaches of the Han River,the middle reaches of the Yangtze River,the Taihu Lake basin,the Lixia River basin,the Huang-Huai-hai Plain and the Weihe River Plain.[Conclusion]The results show that from the perspective of network analysis,the water network is regarded as a topological network to calculate the accessibility of the water network,and the application in large scale area is realized.At the same time,the influence of water intake cost and resistance on local accessibility is considered,which increases the accuracy of accessibility result.This provides an important basis for the realization of fine water resources management.