浙东沿海城镇化对河网水系的影响

我国东南沿海地区,近年来由于城镇化的快速发展,河网水系结构遭到了较大破坏,导致了洪涝、干旱和水质恶化等一系列生态环境问题。为此以浙东沿海鄞东南平原区为例,以GIS技术作支撑,利用航空遥感图像作为信息源,采用河网水系分级量算统计和图形叠加对比等方法,通过城镇化过程中河网形态结构的变化,分析了鄞东南地区河网水系的变化情况,揭示了城镇化的发展与河网演化之间的联系,并定量预测了研究区在目前城镇化速度下的河网结构变化趋势;在此基础上探讨了遏制这种发展趋势的措施,即在城镇化过程中应多保留现有的河道水系,尤其是村镇级中小河道,重视河网结构与功能的恢复,才能改善河网水质和水生态环境。

Influences of urbanization on river network in the coastal areas of East Zhejiang province

The river network structure changes much with the development of urbanization in the coastal area of Southeast China. As a result, a series of ecological problems such as the flood and waterlogging disaster, drought and the deterioration of water quality occur. We take the Southeast Yin plain area in the coastal areas of East Zhejiang province as an example in this paper. With the support of GIS technique, and the aerial pictures as main information resources, the changes of river network in the study area are discussed by analyzing the change of river structure due to urbanization adopted measurement, the statistics of river gradation and the map overlaying. Besides, the correlation between the urban expansion and the river network evolution is studied, and the trends of river structure changes under the present urbanization in the study area are qualitatively forecasted. Based on these, the measures to avoid the trends are discussed, that is, the existing riverways should be reserved as much as possible in the course of urbanization, especially the small and medium river channels. The restoration of river network structure and functions should be attached much importance so as to improve the urban water quality and water environment. The study will provide reference for the protection of river network during urbanization in the coastal area of Southeast China.