太湖平原圩区河网演变模式探析

Exploring the evolution of river networks in plain polders of Taihu Lake basin

以汾湖镇为研究区,采用GIS和RS方法分析了全镇及典型圩区近15年来河网结构的变化特征。结果表明:等级最低的圩内河道的河网结构变化显著,而村级以上的骨干河网结构基本没有变化,河网结构趋于稳定;不同圩区河网结构变化存在明显的时空差异。快速城镇化过程中,经过及时规划和治理的圩区河网结构得到了一定的改善,反之,河网结构受到了较大破坏;根据河网结构演变特征及原因,快速城镇化圩区河网结构演变的主要原因是对水系的保护、整治和破坏等人类活动的影响,据此识别圩区河网演变的几种主要模式为:主动引导型、被动改造型、修复完善型和保护优先型。

Better understanding of the temporal and spatial evolution of river networks in plain polders of the Taihu basin is essential for the management planning and development in the region.Using geographic information system（GIS） and remote sensing（RS） technologies,the evolution of river networks in the Fenhu town and other typical polders in the region is explored for the period 1994—2009.Results show that there exists a distinctive variation in lower-order streams within polders,while little change occurs in higher-order streams.The spatial variations of river networks among the 6 typical polders are significantly different from each other.In times of rapid urbanization,a river network could be improved should the rivers in polders be well managed and controlled,and vice versa.Based on the evolution of river networks and the rate of urbanization in each polder,a river network has four evolutionary modes,which are the active conduction mode,the passive transformation mode,the restoration and recovery mode,and the priority protection mode.Main reasons for the revolution are mankind’s activities such as river network protection,enhancement and destroy,so there is no specific relationship between the urbanization and the evolution of river networks within polders.