Based on field-survey hydrological series in the Dongting Lake watershed from 1951 to 2011, the variations of lakebed sediment siltation/erosion（S/E） regimes of the Dongting Lake after the operation of the Three Gor...Based on field-survey hydrological series in the Dongting Lake watershed from 1951 to 2011, the variations of lakebed sediment siltation/erosion（S/E） regimes of the Dongting Lake after the operation of the Three Gorges Reservoir（TGR） were analyzed. Significantly positive correlations were found between the flow rate from Zhicheng and the Three Outlets（r^2=0.859, p〈0.0001）, and between the flow rate and sediment delivery rate at the Three Outlets（r^2=0.895, p〈0.0001）. This indicated that the flow rate and sediment delivery rate at the Three Outlets were largely determined by the flow rate from the upstream Yangtze River. Sediment deposition amount in the Dongting Lake basin dropped from ＋4796.4×10^4 t during the period before the operation of TGR（1999–2002） to ＋684.1×10^4 t, ＋449.8×10^4 t and –559.6×10^4 t during the impoundment Phases I, II and III of TGR. The S/E regimes changed from a siltation-dominant to an erosion-dominant state under the pre-discharge, water-storage and water-supplement dispatch over the impoundment from Phase I to III. The sediment deposition amount decreased dramatically under the flood-storage dispatch over the impoundment Phase I to III. The estimated annual mean flow rate, sediment delivery rate and sediment concentration thresholds were respectively 970.81 m3/s, 466.82 kg/s and 0.481 kg/m3 for the upstream Three Outlets to maintain an erosion-dominant state in the downstream linked the Dongting Lake.展开更多
As agricultural eco-tourism development played a vital role in promoting rural economic and social development and constructing new harmonious countryside,the paper had analyzed environmental problem produced during i...As agricultural eco-tourism development played a vital role in promoting rural economic and social development and constructing new harmonious countryside,the paper had analyzed environmental problem produced during its development,pointed out that blind development of agricultural eco-tourism had seriously destroyed resources and ecological environment and that tourist infrastructure construction and urbanization had ruined rural unique natural landscape.In view of current situation of environment,it also studied reasons causing environmental disruption,which lied in insufficient guidance and support of government,deficient scientific development planning and management system,and poor environmental consciousness of tourist operators and tourists.On this basis,it summarized that agricultural eco-tourism development should follow principles of sustainable development,synchronization between development and protection,and coordination between tourism development and environmental protection.It concluded proper ways to develop agricultural eco-tourism,and emphasized that it should draw up scientific and reasonable development planning,enhance government's macro-administration,establish and perfect ecological compensation mechanism,and strive to cultivate people's environmental awareness.展开更多
基金National Natm＇al Science Foundation of China, No.41071067 Program of the Key Discipline Con- struction of the Physical Geography in Hunan Province.Acknowledgements The authors would like to thank Changjiang （Yangtze） Water Resources Committee and Hunan Hydro ＆ Power Institute for their help in providing the data presented in this work.
文摘Based on field-survey hydrological series in the Dongting Lake watershed from 1951 to 2011, the variations of lakebed sediment siltation/erosion（S/E） regimes of the Dongting Lake after the operation of the Three Gorges Reservoir（TGR） were analyzed. Significantly positive correlations were found between the flow rate from Zhicheng and the Three Outlets（r^2=0.859, p〈0.0001）, and between the flow rate and sediment delivery rate at the Three Outlets（r^2=0.895, p〈0.0001）. This indicated that the flow rate and sediment delivery rate at the Three Outlets were largely determined by the flow rate from the upstream Yangtze River. Sediment deposition amount in the Dongting Lake basin dropped from ＋4796.4×10^4 t during the period before the operation of TGR（1999–2002） to ＋684.1×10^4 t, ＋449.8×10^4 t and –559.6×10^4 t during the impoundment Phases I, II and III of TGR. The S/E regimes changed from a siltation-dominant to an erosion-dominant state under the pre-discharge, water-storage and water-supplement dispatch over the impoundment from Phase I to III. The sediment deposition amount decreased dramatically under the flood-storage dispatch over the impoundment Phase I to III. The estimated annual mean flow rate, sediment delivery rate and sediment concentration thresholds were respectively 970.81 m3/s, 466.82 kg/s and 0.481 kg/m3 for the upstream Three Outlets to maintain an erosion-dominant state in the downstream linked the Dongting Lake.
基金Supported by Part of Research Results of Special Program of Humane Social Science Fund of Guizhou Education Department(09ZX084)~~
文摘As agricultural eco-tourism development played a vital role in promoting rural economic and social development and constructing new harmonious countryside,the paper had analyzed environmental problem produced during its development,pointed out that blind development of agricultural eco-tourism had seriously destroyed resources and ecological environment and that tourist infrastructure construction and urbanization had ruined rural unique natural landscape.In view of current situation of environment,it also studied reasons causing environmental disruption,which lied in insufficient guidance and support of government,deficient scientific development planning and management system,and poor environmental consciousness of tourist operators and tourists.On this basis,it summarized that agricultural eco-tourism development should follow principles of sustainable development,synchronization between development and protection,and coordination between tourism development and environmental protection.It concluded proper ways to develop agricultural eco-tourism,and emphasized that it should draw up scientific and reasonable development planning,enhance government's macro-administration,establish and perfect ecological compensation mechanism,and strive to cultivate people's environmental awareness.
