The heavy floods in the Taihu Basin showed increasing trend in recent years. In this work, a typical area in the northern Taihu Basin was selected for flood risk analysis and potential flood losses assessment. Human a...The heavy floods in the Taihu Basin showed increasing trend in recent years. In this work, a typical area in the northern Taihu Basin was selected for flood risk analysis and potential flood losses assessment. Human activities have strong impact on the study area’s flood situation (as affected by the polders built, deforestation, population increase, urbanization, etc.), and have made water level higher, flood duration shorter, and flood peaks sharper. Five years of different flood return periods [(1970), 5 (1962), 10 (1987), 20 (1954), 50 (1991)] were used to calculate the potential flood risk area and its losses. The potential flood risk map, economic losses, and flood-impacted population were also calculated. The study’s main conclusions are: 1) Human activities have strongly changed the natural flood situation in the study area, increasing runoff and flooding; 2) The flood risk area is closely related with the precipitation center; 3) Polder construction has successfully protected land from flood, shortened the flood duration, and elevated water level in rivers outside the polders; 4) Economic and social development have caused flood losses to increase in recent years.展开更多
The construction of the Three Gorges Dam on the Yangtze River has extensive impact on the ecosystems and the population of the Three Gorges Area (TGA). Inundation and resettlement have induced far-reaching land use an...The construction of the Three Gorges Dam on the Yangtze River has extensive impact on the ecosystems and the population of the Three Gorges Area (TGA). Inundation and resettlement have induced far-reaching land use and land cover change (LUCC). The areas that are affected by measures of resettlement are in a tense situation between the implementation of various governmental tasks addressing sustainable land use and water retention and the fulfilment of the population’s economic needs, which primarily depend on agricultural production. Destabilization of slopes and soil erosion are immediate hazards induced by the impoundment. Farming is a very important source of income and has to persist on the one hand to assure the income of the rural population. On the other hand, the environment has to be protected from runoff, soil erosion and instabilities connected to relief, geology and hydraulic influences. In this study, supervised classifications are performed using Landsat-TM (1987 and 2007) and ASTER (2007) images. LUCC is assessed by post-classification change analysis. On the catchment scale, arable land has decreased significantly, while garden land (citrus orchards) and woodland have increased. LUCC mainly affects the area surrounding the reservoir ("backwater") of the Xiangxi ( 香溪 ) River, driven by local resettlement, newly built infrastructure, relocation of land cultivation, and conversion of arable land to garden land. In the hinterland, LUCC occurs in form of abandonment of land cultivation as a consequence of the Grain-forGreen programme.展开更多
Globally, 2000 was an normal year in terms of economic loss from natural disasters. An analysis of the characters and distribution of major global natural disasters in the year 2000 is made and a discussion on the cau...Globally, 2000 was an normal year in terms of economic loss from natural disasters. An analysis of the characters and distribution of major global natural disasters in the year 2000 is made and a discussion on the causes of these disasters is presented in accordance with collected data of global natural disasters.展开更多
文摘The heavy floods in the Taihu Basin showed increasing trend in recent years. In this work, a typical area in the northern Taihu Basin was selected for flood risk analysis and potential flood losses assessment. Human activities have strong impact on the study area’s flood situation (as affected by the polders built, deforestation, population increase, urbanization, etc.), and have made water level higher, flood duration shorter, and flood peaks sharper. Five years of different flood return periods [(1970), 5 (1962), 10 (1987), 20 (1954), 50 (1991)] were used to calculate the potential flood risk area and its losses. The potential flood risk map, economic losses, and flood-impacted population were also calculated. The study’s main conclusions are: 1) Human activities have strongly changed the natural flood situation in the study area, increasing runoff and flooding; 2) The flood risk area is closely related with the precipitation center; 3) Polder construction has successfully protected land from flood, shortened the flood duration, and elevated water level in rivers outside the polders; 4) Economic and social development have caused flood losses to increase in recent years.
基金supported by the German Federal Ministry of Education and Research (BMBF, No. 03 G 0669)
文摘The construction of the Three Gorges Dam on the Yangtze River has extensive impact on the ecosystems and the population of the Three Gorges Area (TGA). Inundation and resettlement have induced far-reaching land use and land cover change (LUCC). The areas that are affected by measures of resettlement are in a tense situation between the implementation of various governmental tasks addressing sustainable land use and water retention and the fulfilment of the population’s economic needs, which primarily depend on agricultural production. Destabilization of slopes and soil erosion are immediate hazards induced by the impoundment. Farming is a very important source of income and has to persist on the one hand to assure the income of the rural population. On the other hand, the environment has to be protected from runoff, soil erosion and instabilities connected to relief, geology and hydraulic influences. In this study, supervised classifications are performed using Landsat-TM (1987 and 2007) and ASTER (2007) images. LUCC is assessed by post-classification change analysis. On the catchment scale, arable land has decreased significantly, while garden land (citrus orchards) and woodland have increased. LUCC mainly affects the area surrounding the reservoir ("backwater") of the Xiangxi ( 香溪 ) River, driven by local resettlement, newly built infrastructure, relocation of land cultivation, and conversion of arable land to garden land. In the hinterland, LUCC occurs in form of abandonment of land cultivation as a consequence of the Grain-forGreen programme.
文摘Globally, 2000 was an normal year in terms of economic loss from natural disasters. An analysis of the characters and distribution of major global natural disasters in the year 2000 is made and a discussion on the causes of these disasters is presented in accordance with collected data of global natural disasters.
