Roads are conspicuous components in a river landscape;however,their impacts on river landscape patterns and ecological processes have not been systematically studied at the watershed scale.In this paper,the Lancang Ri...Roads are conspicuous components in a river landscape;however,their impacts on river landscape patterns and ecological processes have not been systematically studied at the watershed scale.In this paper,the Lancang River Valley in Yunnan Province,China was selected as a case to study road lateral disconnection and crossing impacts and identify river-road network interaction.This study was primarily focused on the road impacts on soil erosion intensity and patch density by using GIS analysis at different scales and explored their distribution with terrain factors.The results showed that river density revealed spatial autocorrelation although both of the roads and rivers were distributed unevenly in the valley.The lateral road(road curvature≥1.1)proportion correlated with soil erosion intensity(p 0.01)at the small sub-basin scale.Soil erosion intensity decreased with increasing lateral road buffer width.Light erosion generally accounted for a large proportion of the erosion in the lateral road buffer zones(1.0–4.0 km),while higher class lateral roads imposed greater impacts on soil erosion than lower class roads,which primarily had a moderate erosion level.In addition,the results of road-river intersection density indicated that road crossing impacts were significantly correlated with patch density at the small sub-basin scale.Topography factor(percent of slope>25°in each sub-basin had a close relationship with the ratio of total length of road line with curvature value≥1.1 to the total number of intersections.The correlation(p 0.01)between road impacts and terrain factor revealed that topography affected the road impact distribution in the Lancang River Valley.展开更多
River water plays a key role in human health, and in social and economic development, and is often affected by both natural factors and human activities. An in-depth understanding of the role of these factors can help...River water plays a key role in human health, and in social and economic development, and is often affected by both natural factors and human activities. An in-depth understanding of the role of these factors can help in developing an effective catchment management strategy to protect precious water resources. This study analyzed river water quality, patterns of terrestrial and riparian ecosystems, intensity of agricultural activities, industrial structure, and spatial distribution of pollutant emissions in the Haihe River Basin in China for the year of 2010, identifying the variables that have the greatest impact on river water quality. The area percentage of farmland in study area, the percentage of natural vegetation cover in the 1000-m riparian zone, rural population density, industrial Gross Domestic Product(GDP)/km^2, and industrial amino nitrogen emissions were all significantly correlated with river water quality(P < 0.05). Farming had the largest impact on river water quality, explaining 43.0% of the water quality variance, followed by the coverage of natural vegetation in the 1000-m riparian zone, which explained 36.2% of the water quality variance. Industrial amino nitrogen emissions intensity and rural population density explained 31.6% and 31.4% of the water quality variance, respectively, while industrial GDP/km^2 explained 26.6%. Together, these five indicators explained 67.3% of the total variance in water quality. Consequently, water environmental management of the Haihe River Basin should focus on adjusting agricultural activities, conserving riparian vegetation, and reducing industrial pollutant emissions by optimizing industrial structure. The results demonstrate how human activities drive the spatial pattern changes of river water quality, and they can provide reference for developing land use guidelines and for prioritizing management practices to maintain stream water quality in a large river basin.展开更多
This article deals with the important experience of regional planning developed by the CESP (Companhia Energ6tica de Silo Paulo), Brazil, through the implantation of its hydroelectric projects. The company accumulat...This article deals with the important experience of regional planning developed by the CESP (Companhia Energ6tica de Silo Paulo), Brazil, through the implantation of its hydroelectric projects. The company accumulated a large experience in deploying and managing residential centers built to provide support to the works of their dams. The presence of urban planning was verified in all cases studied, with the participation of different professionals such as architects, planners, engineers and landscape designers, from inside or outside the company. This research shows that they used concepts derived from experiences as company towns of 19th century, the neighborhood unit, the garden city, the urbanistic assumptions from CIAM (Congr^s Internationaux d'Architecture Moderne) and the TVA (Tennessee Valley Authority).展开更多
Due to limited in situ data and diagnostic numerical models, the summer circulation structure and formation mechanism in the Beibu Gulf have always been in controversy in the past 50 years. Therefore, a new three-dime...Due to limited in situ data and diagnostic numerical models, the summer circulation structure and formation mechanism in the Beibu Gulf have always been in controversy in the past 50 years. Therefore, a new three-dimensional hindcast model was built within the northwestern South China Sea(SCS), forced with the daily averaged wind, heat flux, lateral flux, as well as tidal harmonic and eight major rivers discharges. And the east boundary was set up far away off the Qiongzhou Strait(QS). Lastly, the model results were consistent with not only the synchronous observation data from the project 908 but also the historical observed data. As a result, the summer circulation structure was revealed that the southern Gulf was occupied by an anticyclonic eddy whereas the northern Gulf was dominated by a cyclonic gyre. Although the circulation major structure was stable, its area and strength had yearly and monthly oscillation. The other three sensitive experiments indicated that the circulations in the southern and northern Gulf were driven by the SCS circulation and monsoon wind, respectively. After the theoretical analysis of the potential vorticity budget, it was further revealed the circulation in the northern Gulf was driven by the positive wind stress curl in summer. Besides, the river discharge was also significant as the vertical circulation had two layer structures outside the mouth of the Red River. Generally, this work calls for the further research on other subjects, such as ocean biogeochemical or marine fisheries.展开更多
The construction of a comprehensive observation platform for natural-resource elements would provide data support for studies of dynamic changes in various natural resources,and could serve the needs of natural-resour...The construction of a comprehensive observation platform for natural-resource elements would provide data support for studies of dynamic changes in various natural resources,and could serve the needs of natural-resource management and the construction of ecological civilization during a period of global change.As the second-largest inland river basin in NW China,the Heihe River Basin(HRB)lies in the central part of the Silk Road Economic Belt,consequently,pilot studies of resource management in the basin are urgently needed.This paper describes the construction of a comprehensive natural-resource elements observation network in the HRB to meet requirements for natural-resource management,based on natural-resource and Earth-system science.Based on current observations and research,thirteen observation stations were established in different river basins through integration with existing stations,reconstruction and upgrading,and new construction.The main types of land-surface resources in the HRB(grassland,forests,rivers,lakes,deserts,wetlands,and farmland)were included in the observation network constructed for the monitoring of natural-resource elements.Long-term,continuous,and stable observation can yield key data concerning coupling processes,trends of change,and rates of change in natural resources.This is of great significance in improving cognitive ability,scientific management,and strategic decision-making regarding natural resources in the HRB,and can provide a reference paradigm for the observation of and research into natural resources in other basins.展开更多
基金Under the auspices of Nonprofit Environment Protection Specific Project of China(No.201209029-4)National Natural Science Foundation of China(No.50939001)
文摘Roads are conspicuous components in a river landscape;however,their impacts on river landscape patterns and ecological processes have not been systematically studied at the watershed scale.In this paper,the Lancang River Valley in Yunnan Province,China was selected as a case to study road lateral disconnection and crossing impacts and identify river-road network interaction.This study was primarily focused on the road impacts on soil erosion intensity and patch density by using GIS analysis at different scales and explored their distribution with terrain factors.The results showed that river density revealed spatial autocorrelation although both of the roads and rivers were distributed unevenly in the valley.The lateral road(road curvature≥1.1)proportion correlated with soil erosion intensity(p 0.01)at the small sub-basin scale.Soil erosion intensity decreased with increasing lateral road buffer width.Light erosion generally accounted for a large proportion of the erosion in the lateral road buffer zones(1.0–4.0 km),while higher class lateral roads imposed greater impacts on soil erosion than lower class roads,which primarily had a moderate erosion level.In addition,the results of road-river intersection density indicated that road crossing impacts were significantly correlated with patch density at the small sub-basin scale.Topography factor(percent of slope>25°in each sub-basin had a close relationship with the ratio of total length of road line with curvature value≥1.1 to the total number of intersections.The correlation(p 0.01)between road impacts and terrain factor revealed that topography affected the road impact distribution in the Lancang River Valley.
基金Under the auspices of National Natural Science Foundation of China(No.41371538)Independent Project of State Key Laboratory of Urban and Regional Ecology,Research Center for Eco-Environmental Sciences,Chinese Academy of Sciences(No.SKLURE2008-1-02)
文摘River water plays a key role in human health, and in social and economic development, and is often affected by both natural factors and human activities. An in-depth understanding of the role of these factors can help in developing an effective catchment management strategy to protect precious water resources. This study analyzed river water quality, patterns of terrestrial and riparian ecosystems, intensity of agricultural activities, industrial structure, and spatial distribution of pollutant emissions in the Haihe River Basin in China for the year of 2010, identifying the variables that have the greatest impact on river water quality. The area percentage of farmland in study area, the percentage of natural vegetation cover in the 1000-m riparian zone, rural population density, industrial Gross Domestic Product(GDP)/km^2, and industrial amino nitrogen emissions were all significantly correlated with river water quality(P < 0.05). Farming had the largest impact on river water quality, explaining 43.0% of the water quality variance, followed by the coverage of natural vegetation in the 1000-m riparian zone, which explained 36.2% of the water quality variance. Industrial amino nitrogen emissions intensity and rural population density explained 31.6% and 31.4% of the water quality variance, respectively, while industrial GDP/km^2 explained 26.6%. Together, these five indicators explained 67.3% of the total variance in water quality. Consequently, water environmental management of the Haihe River Basin should focus on adjusting agricultural activities, conserving riparian vegetation, and reducing industrial pollutant emissions by optimizing industrial structure. The results demonstrate how human activities drive the spatial pattern changes of river water quality, and they can provide reference for developing land use guidelines and for prioritizing management practices to maintain stream water quality in a large river basin.
文摘This article deals with the important experience of regional planning developed by the CESP (Companhia Energ6tica de Silo Paulo), Brazil, through the implantation of its hydroelectric projects. The company accumulated a large experience in deploying and managing residential centers built to provide support to the works of their dams. The presence of urban planning was verified in all cases studied, with the participation of different professionals such as architects, planners, engineers and landscape designers, from inside or outside the company. This research shows that they used concepts derived from experiences as company towns of 19th century, the neighborhood unit, the garden city, the urbanistic assumptions from CIAM (Congr^s Internationaux d'Architecture Moderne) and the TVA (Tennessee Valley Authority).
基金supported by Guangxi Natural Science Foundation(Grant No.2012GXNSFEA053001)the project entitled "The Beibu Gulf forecast circulation system construction and Its Application to the Coastal Pollution Transport"
文摘Due to limited in situ data and diagnostic numerical models, the summer circulation structure and formation mechanism in the Beibu Gulf have always been in controversy in the past 50 years. Therefore, a new three-dimensional hindcast model was built within the northwestern South China Sea(SCS), forced with the daily averaged wind, heat flux, lateral flux, as well as tidal harmonic and eight major rivers discharges. And the east boundary was set up far away off the Qiongzhou Strait(QS). Lastly, the model results were consistent with not only the synchronous observation data from the project 908 but also the historical observed data. As a result, the summer circulation structure was revealed that the southern Gulf was occupied by an anticyclonic eddy whereas the northern Gulf was dominated by a cyclonic gyre. Although the circulation major structure was stable, its area and strength had yearly and monthly oscillation. The other three sensitive experiments indicated that the circulations in the southern and northern Gulf were driven by the SCS circulation and monsoon wind, respectively. After the theoretical analysis of the potential vorticity budget, it was further revealed the circulation in the northern Gulf was driven by the positive wind stress curl in summer. Besides, the river discharge was also significant as the vertical circulation had two layer structures outside the mouth of the Red River. Generally, this work calls for the further research on other subjects, such as ocean biogeochemical or marine fisheries.
基金The National Key Research and Development Program of China(2018YFA0606500)The Special Project for Comprehensive Monitoring of The Natural Resources(Xining Center)(DD20211627)+1 种基金The Comprehensive Observation of Natural-resource Elements in Heihe River Basin(DD20208065)The Investigation of Groundwater Flow Field in Key Areas(Xi’an Center)(DD20211563)。
文摘The construction of a comprehensive observation platform for natural-resource elements would provide data support for studies of dynamic changes in various natural resources,and could serve the needs of natural-resource management and the construction of ecological civilization during a period of global change.As the second-largest inland river basin in NW China,the Heihe River Basin(HRB)lies in the central part of the Silk Road Economic Belt,consequently,pilot studies of resource management in the basin are urgently needed.This paper describes the construction of a comprehensive natural-resource elements observation network in the HRB to meet requirements for natural-resource management,based on natural-resource and Earth-system science.Based on current observations and research,thirteen observation stations were established in different river basins through integration with existing stations,reconstruction and upgrading,and new construction.The main types of land-surface resources in the HRB(grassland,forests,rivers,lakes,deserts,wetlands,and farmland)were included in the observation network constructed for the monitoring of natural-resource elements.Long-term,continuous,and stable observation can yield key data concerning coupling processes,trends of change,and rates of change in natural resources.This is of great significance in improving cognitive ability,scientific management,and strategic decision-making regarding natural resources in the HRB,and can provide a reference paradigm for the observation of and research into natural resources in other basins.