On the basis of natural conditions of lack of rainfall on the Loess Plateau, this paper presents a method of design and construction in rainwater harvesting system for afforestation, which is suitable to the regions o...On the basis of natural conditions of lack of rainfall on the Loess Plateau, this paper presents a method of design and construction in rainwater harvesting system for afforestation, which is suitable to the regions of 300 600?mm rainfall. The system consists of micro catchments of various forms and sizes that include planting areas, where trees are planted and trapped runoff, and contributing areas, where overland flow are produced by rainfall. The design is based on rainfall, runoff coefficients of contributing areas, evapotranspiration of trees and soil surface, water deficiency of soil, and environmental capacity of precipitation in the region, and so on. Runoff coefficient of contributing areas with YJG (organic silicon chemical treatment), compacted surface soil slope and natural slope micro catchments, are 0 8 0 89, 0 23 0 36, and 0 08 0 10 respectively. According to the Penman method, the soil water deficiency varies from 50?mm to 300?mm. In the region of 400?mm precipitation, the contributing area treated with YJG is 3 4?m 2 for timber forests, 8 10?m 2 for cash trees respectively; the contributing area treated with compacted soil surface is 6 8?m\+2 for timber forests, 10 12?m 2 for cash trees respectively; the contributing area of natural slope is 8 10?m 2 for timber forests, 12 15?m 2 for cash trees respectively. Transpiration from trees of micro catchment in YJG, compacted surface soil and natural slope treatment is by 47 65% 53 31%, 24 10% 36 93%, and 18 65% 29 55% of total rainfall (rainfall and harvested rainwater) respectively after the system was applied in the region. This system, which has been widely practising on the Loess Plateau, is now known as runoff forestry.展开更多
Australia is one of the world leaders in water management. The country meets the challenge of water shortage with established integrated water management in which rainwater is taken as a too precious resource to be ju...Australia is one of the world leaders in water management. The country meets the challenge of water shortage with established integrated water management in which rainwater is taken as a too precious resource to be just drained off. In Australia, rainwater is extensively harvested and polished to provide cheaper supply for potable and non-potable domestic uses, irrigation, landscaping, refilling aquifers and other uses. Implementing dual management over the quantity and quality of storm water and practicing water sensitive urban design (WSUD) in urban areas effectively control non-point-source pollution of waterways by pollutants carried with runoffs, reduce the discharge of rainwater and thus protect properties and lives from damage by floods. These achievements are attributed to constant reinforcement by govenments from federal to local levels in policy, financial, legal and educational aspects, and also to the lasting efforts of professional communities and water industry in developing requisite techniques, demonstrating the benefits and fostering public credence of rainwater reuse. The successful rainwater management practices in Australia suggest rainwater harvesting can be a complimentary means for the South-to-North Water Transfer Scheme to solve the water shortage in China's northern regions, and thus release to a degree the pressure on the Yangtze water resources. Best management practices of rainwater can be an effective controlling strategy for flooding and non-point-source water pollution of waterways. Such in-site source control initiatives have particular significance to protecting slow waterways of weak self-purification ability, like the Three Gorges Reservior.展开更多
Based on an analysis of our research results and the main problems relating to urban rainwater treatment, we propose a new approach to urban rainwater management in China. The necessity and feasibility of such a new a...Based on an analysis of our research results and the main problems relating to urban rainwater treatment, we propose a new approach to urban rainwater management in China. The necessity and feasibility of such a new approach are discussed. From an ecological point of view all components of the global system, including residents living in cities, have the same right to enjoy rainwater. Therefore, urban rainwater should neither be simply drained as waste water, nor be completely harvested as a kind of resource. The objective of this new approach is to maintain the natural hydrological cycle in urban areas during urbanization. When necessary, it could also be used to regulate the amount of runoff, evaporation and infiltration in a city in order to rehabilitate the hydrological cycle given the local conditions. Three basic principles should be adopted in rainwater management, i.e., separation of rainfall from sewage, limited utilization and small and decentralized facilities. Four methods can be used for urban rainwater management: rainwater harvest, rainwater infiltration, rainwater storage and rainwater pipes. The natural hydrological cycle in urban areas could be rehabilitated through rainwater management, which is of great importance for sustainable development of our cities.展开更多
One of the tremendous impacts of the urbanization on the ecological enviroument in urbau areas is the fatal destruction or the natural hydrological cycle. However less attention has up to now been paid to this kind of...One of the tremendous impacts of the urbanization on the ecological enviroument in urbau areas is the fatal destruction or the natural hydrological cycle. However less attention has up to now been paid to this kind of destroy, because it is covered by the problem of increasingly serleus water shortage. In terms of changing the human interactions with the environmeat, are nature-oriented mode for rainwater management in urban areas are proposed All the destructions of the astural hydrological cycle caused by urbanization should ecoloically be compensated in time so that the groundwater can be recharged and the natural cycle be recovered gradually. Such modes can be divided into three classes:catchment, storage and drainage. Based on an analysis of the natural condttions about the local climate, topography and hydrogeology, an appropriated mode can be selected to meet the needs of an old urban area or a newly built one.展开更多
The sustainable water system (SWS) was interpreted based on green residential zone associated codes issued by P.R.China and some other countries,and ecological principles.Its constitution,designing and engineering,and...The sustainable water system (SWS) was interpreted based on green residential zone associated codes issued by P.R.China and some other countries,and ecological principles.Its constitution,designing and engineering,and economic and environmental benefits were illustrated with a case of a campus construction project.The SWS incorporates divided nature drainage systems,grey water treatment and reuse technologies,rainwater decentralized collection and purification technologies,and water quality safeguard techniques for reclaimed water reused for landscaping.Application of the SWS is expected to gain remarkable economic and environmental benefits by reducing both the demand for municipal water supply and sewage discharge.展开更多
To meet the demand of urban rainwater integrated management,we designed and complemented a physical simulation experimental system of urban rainfall infiltration regulation parameters.We discuss the feasibility of qua...To meet the demand of urban rainwater integrated management,we designed and complemented a physical simulation experimental system of urban rainfall infiltration regulation parameters.We discuss the feasibility of quantitative regulations of urban underlying surface rainfall infiltration conditions and a practical application of a simulated experimental system.In a com- prehensive analysis of the composition of an effective rainwater harvesting system and selection of water storage material,we simulated the major parameters of an experimental area rainfall,soil moisture and water storage capacity by providing an effective regulation of the experimental area runoff coefficient,obtained from basic data.展开更多
Mud pumping induced by moving train loads on rainwater-intruded roadbed causes intensive track vibrations and threatens safety of high-speed trains.In this paper,a vehicle–track–subgrade finite element model was est...Mud pumping induced by moving train loads on rainwater-intruded roadbed causes intensive track vibrations and threatens safety of high-speed trains.In this paper,a vehicle–track–subgrade finite element model was established to analyze the dynamic responses of a ballastless track,and results showed that the concrete base and roadbed were detached because of the whipping effect arising from the rainwater intrusion channel.An in-situ soil core test showed that the intruded rainwater accumulated in roadbed to form standing water and saturated the roadbed.The flapping action of the concrete base caused by the whipping effect led to mud formation mixed with fine particles and rainwater,which migrated upward under the pore-water pressure(PWP)gradient.Mud pumping resulted from continuous particle migration in the saturated roadbed under moving train loads:under normal roadbed condition,coarse and fine particles were uniformly distributed in the roadbed;in early period of mud pumping,fine particles migrated downward to bottom of the roadbed because of the rainwater infiltration flow;in middle stage of mud pumping,fine particles migrated upward and gathered at the roadbed surface under PWP gradient;in later period of mud pumping,fine particles were entrained and removed with the dissipation of excess PWP.Moreover,a full-scale physical model was established to reproduce mud pumping,and polyurethane injection remediation against mud pumping was validated on this physical model.The remediation method was applied to an in-situ mud pumping.The deviation of the vertical track profile reduced remarkably and remained at a low level within half a year,showing a good long-term service performance of the polyurethane remediated roadbed.展开更多
文摘On the basis of natural conditions of lack of rainfall on the Loess Plateau, this paper presents a method of design and construction in rainwater harvesting system for afforestation, which is suitable to the regions of 300 600?mm rainfall. The system consists of micro catchments of various forms and sizes that include planting areas, where trees are planted and trapped runoff, and contributing areas, where overland flow are produced by rainfall. The design is based on rainfall, runoff coefficients of contributing areas, evapotranspiration of trees and soil surface, water deficiency of soil, and environmental capacity of precipitation in the region, and so on. Runoff coefficient of contributing areas with YJG (organic silicon chemical treatment), compacted surface soil slope and natural slope micro catchments, are 0 8 0 89, 0 23 0 36, and 0 08 0 10 respectively. According to the Penman method, the soil water deficiency varies from 50?mm to 300?mm. In the region of 400?mm precipitation, the contributing area treated with YJG is 3 4?m 2 for timber forests, 8 10?m 2 for cash trees respectively; the contributing area treated with compacted soil surface is 6 8?m\+2 for timber forests, 10 12?m 2 for cash trees respectively; the contributing area of natural slope is 8 10?m 2 for timber forests, 12 15?m 2 for cash trees respectively. Transpiration from trees of micro catchment in YJG, compacted surface soil and natural slope treatment is by 47 65% 53 31%, 24 10% 36 93%, and 18 65% 29 55% of total rainfall (rainfall and harvested rainwater) respectively after the system was applied in the region. This system, which has been widely practising on the Loess Plateau, is now known as runoff forestry.
基金Partly financed by the Training Fund of the State Administration of Foreign Experts Affairs, P. R. China.
文摘Australia is one of the world leaders in water management. The country meets the challenge of water shortage with established integrated water management in which rainwater is taken as a too precious resource to be just drained off. In Australia, rainwater is extensively harvested and polished to provide cheaper supply for potable and non-potable domestic uses, irrigation, landscaping, refilling aquifers and other uses. Implementing dual management over the quantity and quality of storm water and practicing water sensitive urban design (WSUD) in urban areas effectively control non-point-source pollution of waterways by pollutants carried with runoffs, reduce the discharge of rainwater and thus protect properties and lives from damage by floods. These achievements are attributed to constant reinforcement by govenments from federal to local levels in policy, financial, legal and educational aspects, and also to the lasting efforts of professional communities and water industry in developing requisite techniques, demonstrating the benefits and fostering public credence of rainwater reuse. The successful rainwater management practices in Australia suggest rainwater harvesting can be a complimentary means for the South-to-North Water Transfer Scheme to solve the water shortage in China's northern regions, and thus release to a degree the pressure on the Yangtze water resources. Best management practices of rainwater can be an effective controlling strategy for flooding and non-point-source water pollution of waterways. Such in-site source control initiatives have particular significance to protecting slow waterways of weak self-purification ability, like the Three Gorges Reservior.
基金Projects 40371113 supported by the National Natural Science Foundation of China and OF060096Young Foundation of China University of Mining &Technology
文摘Based on an analysis of our research results and the main problems relating to urban rainwater treatment, we propose a new approach to urban rainwater management in China. The necessity and feasibility of such a new approach are discussed. From an ecological point of view all components of the global system, including residents living in cities, have the same right to enjoy rainwater. Therefore, urban rainwater should neither be simply drained as waste water, nor be completely harvested as a kind of resource. The objective of this new approach is to maintain the natural hydrological cycle in urban areas during urbanization. When necessary, it could also be used to regulate the amount of runoff, evaporation and infiltration in a city in order to rehabilitate the hydrological cycle given the local conditions. Three basic principles should be adopted in rainwater management, i.e., separation of rainfall from sewage, limited utilization and small and decentralized facilities. Four methods can be used for urban rainwater management: rainwater harvest, rainwater infiltration, rainwater storage and rainwater pipes. The natural hydrological cycle in urban areas could be rehabilitated through rainwater management, which is of great importance for sustainable development of our cities.
文摘One of the tremendous impacts of the urbanization on the ecological enviroument in urbau areas is the fatal destruction or the natural hydrological cycle. However less attention has up to now been paid to this kind of destroy, because it is covered by the problem of increasingly serleus water shortage. In terms of changing the human interactions with the environmeat, are nature-oriented mode for rainwater management in urban areas are proposed All the destructions of the astural hydrological cycle caused by urbanization should ecoloically be compensated in time so that the groundwater can be recharged and the natural cycle be recovered gradually. Such modes can be divided into three classes:catchment, storage and drainage. Based on an analysis of the natural condttions about the local climate, topography and hydrogeology, an appropriated mode can be selected to meet the needs of an old urban area or a newly built one.
基金Funded by the 6th Framework EU Research Program:Sustainable Water Management Improves Tomorrow's Cities Health (SWITCT)
文摘The sustainable water system (SWS) was interpreted based on green residential zone associated codes issued by P.R.China and some other countries,and ecological principles.Its constitution,designing and engineering,and economic and environmental benefits were illustrated with a case of a campus construction project.The SWS incorporates divided nature drainage systems,grey water treatment and reuse technologies,rainwater decentralized collection and purification technologies,and water quality safeguard techniques for reclaimed water reused for landscaping.Application of the SWS is expected to gain remarkable economic and environmental benefits by reducing both the demand for municipal water supply and sewage discharge.
基金Projects 40371113 supported by the National Natural Science Foundation of ChinaOF060096 by the Youth Scientific Foundation of China University of Mining & Technology
文摘To meet the demand of urban rainwater integrated management,we designed and complemented a physical simulation experimental system of urban rainfall infiltration regulation parameters.We discuss the feasibility of quantitative regulations of urban underlying surface rainfall infiltration conditions and a practical application of a simulated experimental system.In a com- prehensive analysis of the composition of an effective rainwater harvesting system and selection of water storage material,we simulated the major parameters of an experimental area rainfall,soil moisture and water storage capacity by providing an effective regulation of the experimental area runoff coefficient,obtained from basic data.
基金This article was supported by the National Natural Science Foundation of China(No.52125803,No.51988101,and No.52008369)the National Key Research and Development Program(No.2018YFE0207100).
文摘Mud pumping induced by moving train loads on rainwater-intruded roadbed causes intensive track vibrations and threatens safety of high-speed trains.In this paper,a vehicle–track–subgrade finite element model was established to analyze the dynamic responses of a ballastless track,and results showed that the concrete base and roadbed were detached because of the whipping effect arising from the rainwater intrusion channel.An in-situ soil core test showed that the intruded rainwater accumulated in roadbed to form standing water and saturated the roadbed.The flapping action of the concrete base caused by the whipping effect led to mud formation mixed with fine particles and rainwater,which migrated upward under the pore-water pressure(PWP)gradient.Mud pumping resulted from continuous particle migration in the saturated roadbed under moving train loads:under normal roadbed condition,coarse and fine particles were uniformly distributed in the roadbed;in early period of mud pumping,fine particles migrated downward to bottom of the roadbed because of the rainwater infiltration flow;in middle stage of mud pumping,fine particles migrated upward and gathered at the roadbed surface under PWP gradient;in later period of mud pumping,fine particles were entrained and removed with the dissipation of excess PWP.Moreover,a full-scale physical model was established to reproduce mud pumping,and polyurethane injection remediation against mud pumping was validated on this physical model.The remediation method was applied to an in-situ mud pumping.The deviation of the vertical track profile reduced remarkably and remained at a low level within half a year,showing a good long-term service performance of the polyurethane remediated roadbed.
