| Land use change is not only one of the hot topics of global change research, but also a hot and foreland topic of global environment research. Wetland is called kidney of the earth. Lake Nansihu, the largest freshwater lake in North China region, is also the largest lake as well as the primary water source of Shandong province. What's more, it's also an important hinge on eastern route of South-to-north water diversion project. Land use change about wetland area of Lake Nansihu is the response of man-land relationship changes of this area. As a shallow-papilionaceous lake, Lake Nansihu has a flat and shallow bottom, which provides favorable conditions for rapidly run-up water levels. And all this makes flood of this area easy to take place. In-depth research on land use change of wetland area of Lake Nansihu under the compel of flood risk, can help to relief the contradiction between cultivated land protection and wetland restoration in the area where returning cultivated land to lake has taken place, thus offering guidance for wetland protection and land use in wetland area of Lake Nansihu where eastern route of South-to-north water diversion project go through; Such research can also provide scientific proof and support for sustainable use of land resources of this area.The first part of this paper discusses about the status and trend of land use change research both home and abroad. And then, on the basis of summarizing the current scholarship, this paper points out the main contents and methods of this research, and formulates technique route as well.The second part of this paper mainly describes the physical geography and socio-economic overviews of the wetland area of Lake Nansihu, discusses the lake's historical drought and flood disasters, and elaborates its hydrological characteristics and current status on land use.The third part analyzes the flood risk of the wetland area of Lake Nansihu, which concludes that the rainfall and water use in industry and agriculture is the main reason for water level changes. And then, we analyzes the hydrological characteristics of typical years, which are 1998 and 2003, the years of flood and 2002, the year of drought. Finally, based on the years' (1951-2007) water level data, the area curve of water level of Lake Nansi is updated.In the fourth part, using TM images of Lake Nansihu in 1987, 1997, 2004 combined with special materials and survey data, we extract the remote sensing information of the wetland area of Lake Nansihu. And based on this, we conduct the analysis on Lake Nansihu's land use change, which concludes that the conversion between cultivated land and wetland is the main transfer patterns of Lake Nansihu's land use, and flood changes driving force, natural driving force (mainly precipitation) and human driving force (including land reclamation, artificial breeding, Lake in the policy and market economy) are the main reasons for land use change of Lake Nansihu.The fifth part makes a conclusion that the flood risk has important influence on the transfer changes between the cultivated land in the humid area of Lake Nansihu and wetland, by setting the reoccurrence water level of the 1998 flood water and analyzing on the two different flood risk scenarios of Lake Nansihu after the eastern route of South-to-north water diversion project completed.On the basis of the above research, this paper points out that we should do well with the contradiction between cultivated land protection and wetland restoration, and the relationship between reverting cultivated land to wetland, wetland restoration, pond lakes restoration and construction of artificial wetland. Meanwhile, we should pay close attention to changes of Lake Nansihu's water levels in order to improve flood resistance ability of Lake Nansihu.
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