基于电路理论模拟秦淮河流域水域连通性

Simulation of Water Connectivity in Qinhuai River Basin Based on Circuit Theory

引入景观生态学中的电路理论方法,基于不同时期土地利用数据,模拟1995-2018年秦淮河流域的水域连通性;采用Landsat7,8影像数据,利用改进水体指数(MNDWI)提取流域水淹区域,分析水域连通性对洪涝灾害风险的可能影响。结果表明,2000年以来流域水域连通性破碎程度明显增加,甚至出现大范围空值区域;连通度密集出现低值碎斑的区域与卫星监测频繁出现水淹的区域相吻合;其中,南京主城区2000-2005年期间,水域连通性下降2.7%,同时水淹面积有一定涨幅,2005年之后南京主城区水域连通性有所改善;江宁区水域连通性在2010-2018年期间下降3.4%,水淹面积则增长近136.4%。研究表明,运用电路理论模拟流域水域连通性具有一定的实用性。

In the past three decades,Qinhuai River basin has experienced rapid urbanization,which has changed the water system structure and connectivity pattern of river network in the basin and increased the risk of flood in the basin.This paper introduced the circuit theory in landscape ecology and simulates the water connectivity of Qinhuai River basin from 1995 to 2018 based on land use data in different periods.Using Landsat7 image data,the flooded area of the basin was extracted by using the improved water body index(MNDWI),and the possible impact of water connectivity on flood disaster risk was analyzed.The results show that since 2000,the degree of fragmentation of water connectivity in the basin has increased significantly,and even a wide range of null value areas have appeared.The areas with dense patches of low connectivity are consistent with the areas of frequent flooding monitored by satellite.Among them,the water area connectivity in the main urban area of Nanjing decreased by 2.7%from 2000 to 2005.At the same time,the flooded area increased to a certain extent.After 2005,the water area connectivity in the main urban area of Nanjing improved.The water connectivity of Jiangning District decreased by 3.4%from 2010 to 2018,and the flooded area increased by nearly 136.4%.The circuit theory is practicable to simulate water connectivity in the Qinhuai River Basin.