Abstract:

In recent years， the water area of lake is reducing with the development of the economic and increasing of the population.It is not only affect the ability of flood diversion and storage,but also lead to the destruction of the ecological environment and decreasing of the water environment quality.Taking the Hongze Lake as an object of study,the dynamic changing of the water area was studied in 70 years(1930~2001) with the support of the technology of GIS and RS by collecting the topographic map and remote sensing image in different stage.The results showed that water area of Hongze Lake reduced 130.3 km2 from 1930 to 1961 and the annual decrease rate was 0.23%；from 1961 to 1971 Hongze Lake area reduced 31.99 km2 and the annual decrease rate was 0.17%;from 1971 to 2001 Hongze Lake area reduced 154.93 km2 and the annual decrease rate was 0.3%；from 1930 to 2001 Hongze Lake area reduced 317.22 km2 and the annual decrease rate was 0.24%.The main change of water area was located at the west and northeast of the Hongze Lake where wetland resource was abundant.At the same time, we also studied the dynamic changes of the lake shorelines in Hongze basin based on the two physical properties of lake,perimeter and area,applying the boxdimension and the fractal dimension.The result showed that the sinuosity of shoreline and the perimeters reduced,and the structure of shorelines became monotonous during the past 30 years.At that time,human activities such as some irrigation works built up around the lake and reclaimed lake wetlands were the immediate cause leading to the decreasing of fractal dimension of the shoreline in the Hongze Lake. In order to realize the sustainable development of economy and society of the Hongze Lake,we discussed the issue how to use water resources in reason and protect water environment at the end of this article based on the above analysis and investigation on the spot.