Soil erosion and subsequent sedimentation have caused serious environmental and soil degradation problems in Okinawa Prefecture,Japan.This research aims at evaluating an availability of the Revised Universal Soil loss...Soil erosion and subsequent sedimentation have caused serious environmental and soil degradation problems in Okinawa Prefecture,Japan.This research aims at evaluating an availability of the Revised Universal Soil loss Equation（RUSLE） for predicting the range of soil loss values for the Nago watershed in Okinawa.It shows that climatic conditions substantially influence the rainfall amount as a function of the I30 of the rainfall event.The rate of soil loss is higher with increasing in altitude due to greater slope steepness.By rainfall data analysis,it is concluded that the large difference in soil loss between 2000 and 2001 was due to concentrated heavy rainfall in the rainy season or the typhoon season.展开更多
According to a lot of hydrological and environmental monitoring data, the condition of soil and water loss in the Lancang River Mekong River watershed (in Yunnan section, China) is described. The occurrence and devel...According to a lot of hydrological and environmental monitoring data, the condition of soil and water loss in the Lancang River Mekong River watershed (in Yunnan section, China) is described. The occurrence and development of soil and water loss is analyzed. The conclusion is that: (1) generally, the situation of soil and water loss in the Lancang River Mekong River watershed (in Yunnan section, China) is light, however, soil and water loss in some regions is serious, especially in the middle reach area of the river; (2) soil and water loss in the Lancang River Mekong River (in Yunnan section, China) watershed presents developing tendency and it is mainly caused by human beings. In accordance with these results, the control measures for soil and water loss are discussed.展开更多
The black soil region of Northeast China is one of the most important food production bases and commodity grain bases in China. However, the continual loss and degradation of precious black soil resources has led to d...The black soil region of Northeast China is one of the most important food production bases and commodity grain bases in China. However, the continual loss and degradation of precious black soil resources has led to direct threats to national food security and regional sustainable development. Therefore, it is necessary to summarize integrated prevention and control experience of small watersheds in black soil region of Northeast China. Tongshuang small watershed, a typical watershed in rolling hills of typical black soil areas in Northeast China, is selected as the study area. Based on nearly 50 years' experience in prevention and control of soil and water loss, the structures and overall benefits of an integrated prevention and control system for soil and water loss are investigated. Then, the 'three defense lines' tri-dimensional protection system with reasonable allocation of different types of soil and water control measures from the hill top to gully is systematically analyzed. The first line on the top hill can weaken and block uphill runoff and sediment, hold water resources and improve soil property. The second line on the hill can truncate slope length, slow down the runoff velocity and reduce erosion energy. The third line in the gully is mainly composed of waterfall engineering, which can inhibit soil erosion and restore land resources. The 'three defense lines' system is feasible for soil and water loss control of small watersheds in the typical black soil region of Northeast China. Through the application of the in Tongshuang small watershed, There are effective improvements in ecological conditions in Tongshuang small watershed after the application of 'three defense lines' soil and water control system. Moreover, the integrated treatment paradigm for soil and water loss in typical black soil region is compared with that in loess region. The results of this study could offer references and experiences for other small watersheds in typical black soil region of Northeast China.展开更多
To investigate the effects of various erosion control measures on mountain floods, a case study was conducted in Censhui River South Branch Watershed using scenario analysis and soil conservation service （SCS） metho...To investigate the effects of various erosion control measures on mountain floods, a case study was conducted in Censhui River South Branch Watershed using scenario analysis and soil conservation service （SCS） methods. A distributed hydrological model was developed, and watershed parameters were determined based on satellite imagery, digital terrain models, digital maps and field investigations. Two types of erosion control measures were investigated： the variation of vegetation covers and the change of cultivation techniques. Seven scenarios were considered for the test watershed. The results show： （1） while the de-vegetation results in the increase of peak discharge, the improve of vegetation covers decreases peak discharge at watershed scale; （2） by both improving vegetation cover and enhancing terrace-cultivation technology, the peak discharge is reduced and the peak flow arrival time is delayed; （3） attention should be attached to both early warning system and measures changing the underlying surface and conveyance systems.展开更多
基金Supported by The United Graduate School of Agriculture Sciences of Kagoshi ma University,Japan(1366039)
文摘Soil erosion and subsequent sedimentation have caused serious environmental and soil degradation problems in Okinawa Prefecture,Japan.This research aims at evaluating an availability of the Revised Universal Soil loss Equation（RUSLE） for predicting the range of soil loss values for the Nago watershed in Okinawa.It shows that climatic conditions substantially influence the rainfall amount as a function of the I30 of the rainfall event.The rate of soil loss is higher with increasing in altitude due to greater slope steepness.By rainfall data analysis,it is concluded that the large difference in soil loss between 2000 and 2001 was due to concentrated heavy rainfall in the rainy season or the typhoon season.
文摘According to a lot of hydrological and environmental monitoring data, the condition of soil and water loss in the Lancang River Mekong River watershed (in Yunnan section, China) is described. The occurrence and development of soil and water loss is analyzed. The conclusion is that: (1) generally, the situation of soil and water loss in the Lancang River Mekong River watershed (in Yunnan section, China) is light, however, soil and water loss in some regions is serious, especially in the middle reach area of the river; (2) soil and water loss in the Lancang River Mekong River (in Yunnan section, China) watershed presents developing tendency and it is mainly caused by human beings. In accordance with these results, the control measures for soil and water loss are discussed.
基金Supported by the National Natural Science Foundation of China,Science Foundation for Youths ( 41001165,40901133,30901163)
文摘The black soil region of Northeast China is one of the most important food production bases and commodity grain bases in China. However, the continual loss and degradation of precious black soil resources has led to direct threats to national food security and regional sustainable development. Therefore, it is necessary to summarize integrated prevention and control experience of small watersheds in black soil region of Northeast China. Tongshuang small watershed, a typical watershed in rolling hills of typical black soil areas in Northeast China, is selected as the study area. Based on nearly 50 years' experience in prevention and control of soil and water loss, the structures and overall benefits of an integrated prevention and control system for soil and water loss are investigated. Then, the 'three defense lines' tri-dimensional protection system with reasonable allocation of different types of soil and water control measures from the hill top to gully is systematically analyzed. The first line on the top hill can weaken and block uphill runoff and sediment, hold water resources and improve soil property. The second line on the hill can truncate slope length, slow down the runoff velocity and reduce erosion energy. The third line in the gully is mainly composed of waterfall engineering, which can inhibit soil erosion and restore land resources. The 'three defense lines' system is feasible for soil and water loss control of small watersheds in the typical black soil region of Northeast China. Through the application of the in Tongshuang small watershed, There are effective improvements in ecological conditions in Tongshuang small watershed after the application of 'three defense lines' soil and water control system. Moreover, the integrated treatment paradigm for soil and water loss in typical black soil region is compared with that in loess region. The results of this study could offer references and experiences for other small watersheds in typical black soil region of Northeast China.
文摘To investigate the effects of various erosion control measures on mountain floods, a case study was conducted in Censhui River South Branch Watershed using scenario analysis and soil conservation service （SCS） methods. A distributed hydrological model was developed, and watershed parameters were determined based on satellite imagery, digital terrain models, digital maps and field investigations. Two types of erosion control measures were investigated： the variation of vegetation covers and the change of cultivation techniques. Seven scenarios were considered for the test watershed. The results show： （1） while the de-vegetation results in the increase of peak discharge, the improve of vegetation covers decreases peak discharge at watershed scale; （2） by both improving vegetation cover and enhancing terrace-cultivation technology, the peak discharge is reduced and the peak flow arrival time is delayed; （3） attention should be attached to both early warning system and measures changing the underlying surface and conveyance systems.
