Interaction Between River Network Variation And Urbanization Of The Three Estuaries Of Southern Jing River

The Three Estuaries of Southern Jing River(TESJR) located in Dongting Lake plain, where densely river network covered, drainage system developed, and the urbanization process has been speed up in latest 30 years. Urban construction squeezed rivers, with river network destroyed, ecological system is affected too, which lead to severe flood disaster, and coerce the normal water utilization in industry, agriculture and daily life. Thus, this paper taking the change of river network as entry point, explore the river network change on urbanization response and its ecological effect. It will make great importance for river network protection, human-water harmony and sustainable development of economy and society.Changes of river network during the year 1983-2015 of TESJR analyzed by RS and DEM data. Result shows river amount, length and drainage area decreased in a certain extent in latest 33 years, while Horton law can be detected all along; drainage density decreased from 4.21 km/km~2 to 3.09 km/km~2, and water surface rate from 8.96% to 7.47%, other indictors represent river network such as river frequency, area needed by per river length and fractal dimension show downtrend too. River network is simplifying.Summarized the urbanization process of TESJR from aspects of space, population and economy, then analyzed the time series’ correlativity between urbanization process and river network variation with Grey Correlation model. Taking Nanzhou Town of Nan County as an example, analyzed the correlativity between different spatial urbanization levels and river network variation. Using the transfer matrix of land utilization to analysis the transfer between river body and another types of utilization. Lastly, the influence mechanism of urbanization to river network summarized. Results shows that space urbanization influences river network most, population and economy urbanization take second place, and response to urbanization are different among river network indictors; different changing degrees of indictors also can be seen among urban area, suburb and county; Among all the transfer, from cultivated land into river body accounts the most part of transfer into river body which is 93.19%, river body into land for construction accounts the most part of its transfer out which is 99.06%. dumping and remediation are two ways that urbanization act on river network, objective of human activity, urbanization level and river grade are the three factors that affect the action, and as an result, river network is going from diversification to simplification, from complexity to simplexes.Based on the analysis of the essence of the influence from river network to urbanization, disserted the influence from river network variation to urbanization, and carried out the quantitative evaluation by the concept of Ecological Service Value. Result shows: 1) the essence of influence is the constraint triggered by deterioration of water ecological subsystems to the social-economical subsystem. 2) the influence includes three levels and seven aspects: urban security(reservoir flood control, daily water and agricultural water), the urban economic,(industrial water and aquaculture) and urban landscape(living environment and biodiversity). 3) river network variation effect the urban economic most, with the largest value loss of ￥797 million, and has the biggest influence on industrial water and reservoir flood control aspect, value loss of ￥6.36 and ￥392 million respectively.Finally, from the coupling coordination of urbanization and river network, advises proposed from the aspects of drainage structure and urbanization.