It is important to understand how land use change impacts groundwater recharge, especially for regions that are undergoing rapid urbanization and there is limited surface water. In this study, the hydrological process...It is important to understand how land use change impacts groundwater recharge, especially for regions that are undergoing rapid urbanization and there is limited surface water. In this study, the hydrological processes and re- charge ability of various land use types in Guishui River Basin, China (in Beijing Municipality) were analyzed. The impact of land use change was investigated based on water balance modeling, WetSpass and GIS. The results indicate that groundwater recharge accounts for only 21.16% of the precipitation, while 72.54% is lost in the form of evapotranspiration. The annual-lumped groundwater recharge rate decreases in the order of cropland, grassland, urban land, and forest. Land use change has resulted in a decrease of 4 x 106 m3 of yearly groundwater recharge in the study area, with a spatially averaged rate of 100.48 mm/yr and 98.41 mm/yr in 1980 and 2005, respectively. This variation has primarily come from an increase of urban area and rural settlements, as well as a decrease of cropland.展开更多
The authors discovered large differences in the characteristics of overflows by the calculation of 1) intercepting volume of overflows for sewer systems using SWMM model which takes into consideration the runoff and ...The authors discovered large differences in the characteristics of overflows by the calculation of 1) intercepting volume of overflows for sewer systems using SWMM model which takes into consideration the runoff and pollutants from rainfalls and 2) the intercepted volume in the total flow at an investigation site. The intercepting rate at the investigation point of CSOs showed higher values than the SSDs. Based on the modeling of the receiving water quality after calculating the intercepting amount of overflows by considering the characteristics of outflows for a proper management of the overflow of sewer systems with rainfalls, it is clear that the BOD decreased by 82.9%-94.0% for the discharge after intercepting a specific amount of flows compared to the discharge from unprocessed overflows.展开更多
The traditional methods of storm sewers design must be supplemented by a precise and systematic analysis of the consequences of urbanization. This will ensure the reduction of the negative effects of urbanization in t...The traditional methods of storm sewers design must be supplemented by a precise and systematic analysis of the consequences of urbanization. This will ensure the reduction of the negative effects of urbanization in the process of stormwater sewer system normal functioning. As the urbanization of rural areas has been in constant progress, there was a need for the development of infrastructure system of urban planning documents that accompany urbanization. Surface storage appears to be one of the solutions that can have positive effects on the consequences of rapid urbanization in terms of preserving water quality of recipients, as well as opportunities to reduce the diameter of drain pipes downstream of surface storage. The necessary investments do not exceed the values of conventional technologies and procedures that are used for this purpose. The restriction of application of these methods is reflected in the limited space, especially in the smaller urban areas, where urbanization was a sudden and uncontrolled process. Future planning documents must contain alternatives like these, while the reservation of required space must be included in the planning documents in which the treatment of further development of the city will be found.展开更多
The projection for groundwater states that the total domestic water demand for greater Bangalore would increase from 1,170 MLD in 2010 to 1,336 MLD in 2016. Dependence on groundwater is ever increasing due to rapid In...The projection for groundwater states that the total domestic water demand for greater Bangalore would increase from 1,170 MLD in 2010 to 1,336 MLD in 2016. Dependence on groundwater is ever increasing due to rapid Industrialization & Urbanization. It is estimated that almost 40% of the population of Bangalore is dependent on groundwater. Due to the unscientific disposal of domestic and industrial waste generated, groundwater is getting highly polluted in the city. The scale of this impact will depend mainly upon the water-service infrastructure, the superficial geology and the regional setting. The quality of ground water is equally important as that of quantity. Jointed and fractured granites and gneisses constitute the major aquifer system of BBMP (Bruhat Bengaluru Mahanagara Palike) area. Two new observatory borewells were drilled and lithology report has been prepared. Petrographic Analysis (XRD/XRF) and Water Quality Analysis were carried out as per the standard methods. Petrographic samples were analysed by collecting chip of rock from the borewell for every 20 ft depth, most of the samples were similar and samples were identified as Biotite-Gneiss, Schistose Amphibolite. Water quality analysis was carried out for individual chemical parameters for two borewells drilled. The 1st Borewell struck water at 150 ft (total depth-200 ft) & 2nd struck at 740 ft (total depth-960 ft). Five water samples were collected till end of depth in each borewell. Chemical parameter values such as, Total hardness (360-348, 280-320) mg/ltr, Nitrate (12.24-13.5, 45-48) mg/ltr, Chloride (104-90, 70-70) mg/ltr, Fe (0.75-0.09, 1.288-0.312) mg/ltr etc. are calculated respectively. Water samples were analysed from various parts of BBMP covering 750 sq kms, also thematic maps (IDW method) of water quality are generated for these samples for post-monsoon season. The study aims to explore the sub-surface lithological layers and the thickness of weathered zone, which indirectly helps to know the groundwater pollution source near surface water bodies, dug wells, etc. The above data are interpreted for future ground water resources planning and management.展开更多
Isotopic tracers and water quality indicators (TDS (Total Dissolved Solid), Cl^- and NO3^-contents) were used to characterize the recharge and control of the quality of groundwater in the alluvial aquifer beneath ...Isotopic tracers and water quality indicators (TDS (Total Dissolved Solid), Cl^- and NO3^-contents) were used to characterize the recharge and control of the quality of groundwater in the alluvial aquifer beneath of the N'djamena city. For this study, a total of 92 waters samples were taken and this included 67 wells, 21 pumps and 4 surface waters. Some groundwater has 6180 and 62H values close to those of the city of N'djamena and/or the Chad river rains. However, all sampled points are below the Global Meteoric Water Line reflecting their evaporated characters. The interpretation of the isotopic tracers highlights that the recharge of the analyzed ground waters may result from two major mechanisms: (1) direct infiltration of local precipitation; (2) lateral inflow of river waters. The upper aquifer is the most vulnerable to pollution, especially during the recharge period. This pollution is due to the leaching of soils during the rainy season and the rise of the groundwater level which accompanies the overflowing of the Chad and causes the leaching of the polluted horizons of the unsaturated zone. In contrast, the lower aquifer has acceptable concentrations of solutes.展开更多
In recent years, the acceleration of urbanization process results in frequent watedoggingj the decline of groundwater level and frequent urban infiasttucture construction pfoblem. In order to better safeguard compl...In recent years, the acceleration of urbanization process results in frequent watedoggingj the decline of groundwater level and frequent urban infiasttucture construction pfoblem. In order to better safeguard complex ecological system and ecological civilization construction in tiie city, and solve the appropriate ratio of water and wetland area to total land area, for water ecological civilization construction in low impact development, the pursuit of water resources sustainability, the pursuit of safety concept, the pursuit of ecological engineeting technology and the pursuit of art are proposed. Based on these pursuits, the principles and design methods of campus landscape creation in colleges and univefsities under the concept of elow impact^ is analyzed. Taking the landscape design, of the shated training base from Jiangsu Vocational Institute of Architectural Technology as an example, how to use the concept of clow impacf? development in actual cases is analyze4 to achieve rainwater collection, water purification, water storage and rainwater ecological utilization, and create a holistic, ecological and diverse sustainable landscape in colleges and universities.展开更多
The drinking water for all the inhabitants of Tangier is still an aim far from being achieved. Therefore, all rural areas and some urban areas feed water wells and springs whose composition and safety are unknown. In ...The drinking water for all the inhabitants of Tangier is still an aim far from being achieved. Therefore, all rural areas and some urban areas feed water wells and springs whose composition and safety are unknown. In the absence of data on water and ignorance of consumers towards the risk of poisoning and waterborne diseases transmitted by these waters, the authors conducted a study to determine the composition, physico-chemical quality and bacteriological these waters. This study is to provide a basic physico-chemical and bacteriological data from these waters in some urban areas of old or missing infrastructure in some sites in the province of Tangier. Such as Ziatine sites, Gzenaya, Rmilate, Malabata + Mnar, Mghoura + Aouama and Downtown. Analyzes are performed according to AFNOR methods (AFNOR: French Standards Association). The results indicate that these waters are generally mild and are experiencing significant geochemical imbalance. Moreover, these waters also have a significant organic and bacteriological pollution. It is concluded that the waters of these sites are of poor quality, unfit for human consumption.展开更多
This paper aims to quantitatively assess water losses of Badovc Lake-Kosovo based on both water balance of the lake and water hydrochemistry. This attempt was strongly prompt by both the importance of this lake for wa...This paper aims to quantitatively assess water losses of Badovc Lake-Kosovo based on both water balance of the lake and water hydrochemistry. This attempt was strongly prompt by both the importance of this lake for water supply of Prishtina city and the lack of water. According to lake water balance, a water loss of 3,738,905 m^3 and 1,722,552 m^3 for the hydrologic year 2014 and the period January-May (2015) was evaluated. These consistent data favour the opinion that a continuous groundwater outflow from the lake is present and it is conditioned by the intensively developed fracture system in the lake basement formations. This was also supported by the chemical data (chloride, sulphate, hardness and electric conductivity etc.) of the water. Water from the leakages on the right side of the dam shows the same chemical signature as the water from the lake. Whereas, water from the piezometer, monitoring well and the gallery of Hajvalia mine show similar values with those of the water from the lake. The calculations of the chloride mass balance showed that the fractions of lake and rainfall waters in the water mixture of Hajvalia mine were 67% and 33% respectively.展开更多
An integrated evaluation system under randomness and fuzziness was developed in this work to systematically assess the risk of groundwater contamination in a little town, Central China. In this system, randomness of t...An integrated evaluation system under randomness and fuzziness was developed in this work to systematically assess the risk of groundwater contamination in a little town, Central China. In this system, randomness of the parameters and the fuzziness of the risk were considered simultaneously, and the exceeding standard probability of contamination and human health risk due to the contamination were integrated. The contamination risk was defined as a combination of "vulnerability" and "hazard". To calculate the value of "vulnerability", pollutant concentration was simulated by MODFLOW with random input variables and a new modified health risk assessment(MRA) model was established to analyze the level of "hazard". The limit concentration based on environmental-guideline and health risk due to manganese were systematically examined to obtain the general risk levels through a fuzzy rule base. The "vulnerability" and "hazard" were divided into five categories of "high", "medium-high", "medium", "low-medium" and "low", respectively. Then, "vulnerability" and "hazard" were firstly combined by integrated evaluation. Compared with the other two scenarios under deterministic methods, the risk obtained in the proposed system is higher. This research illustrated that ignoring of uncertainties in evaluation process might underestimate the risk level.展开更多
The research centered on the groundwater quality parameters in five boreholes and three wells in residential urban areas of Zimbabwe. Ten runs of chemical analysis for water pH, EC (electrical conductivity), water h...The research centered on the groundwater quality parameters in five boreholes and three wells in residential urban areas of Zimbabwe. Ten runs of chemical analysis for water pH, EC (electrical conductivity), water hardness were carried out weekly and averages were calculated for each at Bindura University laboratory. Iron concentrations analysis was done at the Tobacco Research Station. The results from boreholes and wells were compared to the WHO (World Health Organisation) drinking water acceptable standards to measure the deviations. It was found that the boreholes had hard waters (112 mg/L), EC (425 s/m) and iron concentration (0.49 ppm) outside the WHO standards (〉 64 mg/L; 400 s/m; 0.3 ppm respectively). In contrary the wells had only the water pH slightly outside the acceptable ranges (5.8); other parameters were in the acceptable ranges (EC 379 s/m; water hardness 0.38 mg/L as CaCO3 and iron concentration 0.38 ppm). The difference in chemical composition between the boreholes and wells caused the borehole water rejection in favor of well water. High iron concentrations and water hardness in boreholes were major contributors to the water rejection by the residents.展开更多
Groundwater is the water located beneath the earth's surface in the soil pore spaces and in the fractures of rock formations. As one of the most important natural resources, groundwater is associated with the environ...Groundwater is the water located beneath the earth's surface in the soil pore spaces and in the fractures of rock formations. As one of the most important natural resources, groundwater is associated with the environment, public health, welfare, and long-term economic growth, which affects the daily activities of human beings. In modern urban areas, the primary contaminants of groundwater are artificial products, such as gasoline and diesel. To protect this important water resource, a series of efforts have been exerted, including enforcement and remedial actions. Each year, the TGPC (Texas Groundwater Protection Committee) in US publishes a "Joint Groundwater Monitoring and Contamination Report" to describe historic and new contamination cases in each county, which is an important data source for the design of prevention strategies. In this paper, a DDM (data dependent modeling) approach is proposed to predict county-level NCC (new contamination cases). A case study with contamination information from Harris County in Texas was conducted to illustrate the modeling and prediction process with promising results. The one-step prediction error is 1.5%, while the two-step error is 12.1%. The established model can be used at the county-level, state-level, and even at the country-level. Besides, the prediction results could be a reference during decision-making processes.展开更多
In the process of city construction, as a comprised factor of city geological environment, underground water takes the most active part, and its dynamic change is fiercest. The city construction unceasingly disturbs u...In the process of city construction, as a comprised factor of city geological environment, underground water takes the most active part, and its dynamic change is fiercest. The city construction unceasingly disturbs underground water chemical, dynamical, physical and biological field. In return, the four fields' changes also can affect the geological environment that city lived by, in other words they affect safety and stability of geological environment. Interaction of underground water and the geoenvironment directly displays in the following two ways: The first is that the underground water and the geological body transfer the energy each other; the second is that the strength balance of geological body is broken. Underground water variation brought about by city construction is the factor which cannot be neglected. Underground water variation on the one hand changes soils or rocks' physical, biological, chemical and mechanical properties, then influences the deformation and strength of geological body. On the other hand it changes its own physical, chemical properties and biochemical component. At present, from mechanics aspect, interaction between chemical field and biological field variation of the underground water and the geological body lacks research. Although interaction between them is long-term, slow, but when it compared with water-soil or water-rock interaction in the entire process of formation of rocks or soils or geologic evolution history, the qualitative change of the biological and chemical action of rocks or soils brought about by city construction is remarkable, in this paper, aiming at underground water biological field factor which is easily neglected by people, it analyzes that underground water biological field affects possible mechanism and approach of properties variation of rocks or soils in city construction, brings forward further research method and development direction have been also proposed.展开更多
The judicious use and management of natural resources is vital to achieve sustainable development.Land and water are prime natural resources,and their depletion and degradation can lead to serious threats like land su...The judicious use and management of natural resources is vital to achieve sustainable development.Land and water are prime natural resources,and their depletion and degradation can lead to serious threats like land subsidence.Land subsidence is a phenomenon of the alteration of elevation at a point on the earth through the sinking of the surface.It occurs when the earth’s surface loses its support.The major causes of land subsidence include groundwater extraction,mining,construction overload,and other similar factors that increase pressure on the surface and eventually subsidize the land.Urban centers with excessive groundwater extraction and infrastructure development are at a high risk of subsidence.Lahore,the second-largest city in Pakistan,is undergoing an enormous increase in population density,uncontrolled urbanization with very large-scale construction projects,and intensive groundwater extraction which are responsible for subsidence directly or indirectly.Therefore,studies on groundwater status and unplanned urban appraisals have seriously urged monitoring of the subsidence in Lahore.Herein,we used freely available Sentinel-1 data for one year(from August 2018 to August 2019),with a high spatial and temporal resolution,to monitor subsidence in Lahore.The data were processed using the SNAP/Sta MPS approach for Persistent Scatterer Interferometric Synthetic Aperture Radar(PSI)analysis,which is an advanced InSAR technique.The displacement velocity map from InSAR processing shows a significant land deformation in the area with values ranging from-114 to 15 mm yr^(-1).Along with the Sentinel-1 data,we also used supplementary data obtained from various government agencies of Pakistan to study the land cover map,transportation network and waterways of Lahore,soil types,population density,and field points for assessing the results and understanding the roles of various factors in the occurrence of uplift or subsidence.A strong correlation was established between subsidence and various parameters such as groundwater extraction and lowering of the water table,soil type variations,land cover changes,surface water channels,and population density.The deformation map confirms the greatest subsidence in the central part of Lahore,while the uplift is observed in the less populated and rural areas situated near Ravi River.The land subsidence and uplift could be attributed to groundwater extraction and recharge through the canal system and the river,respectively.展开更多
基金Under the auspices of National Natural Science Foundation of China (No. 41101033)Program of International S & T Cooperation (No. 2010DFA92400)+1 种基金Beijing Municipal Natural Science Foundation (No. 8082010)Non-profit Industry Financial Program of the Ministry of Water Resources (No. 200901091)
文摘It is important to understand how land use change impacts groundwater recharge, especially for regions that are undergoing rapid urbanization and there is limited surface water. In this study, the hydrological processes and re- charge ability of various land use types in Guishui River Basin, China (in Beijing Municipality) were analyzed. The impact of land use change was investigated based on water balance modeling, WetSpass and GIS. The results indicate that groundwater recharge accounts for only 21.16% of the precipitation, while 72.54% is lost in the form of evapotranspiration. The annual-lumped groundwater recharge rate decreases in the order of cropland, grassland, urban land, and forest. Land use change has resulted in a decrease of 4 x 106 m3 of yearly groundwater recharge in the study area, with a spatially averaged rate of 100.48 mm/yr and 98.41 mm/yr in 1980 and 2005, respectively. This variation has primarily come from an increase of urban area and rural settlements, as well as a decrease of cropland.
文摘The authors discovered large differences in the characteristics of overflows by the calculation of 1) intercepting volume of overflows for sewer systems using SWMM model which takes into consideration the runoff and pollutants from rainfalls and 2) the intercepted volume in the total flow at an investigation site. The intercepting rate at the investigation point of CSOs showed higher values than the SSDs. Based on the modeling of the receiving water quality after calculating the intercepting amount of overflows by considering the characteristics of outflows for a proper management of the overflow of sewer systems with rainfalls, it is clear that the BOD decreased by 82.9%-94.0% for the discharge after intercepting a specific amount of flows compared to the discharge from unprocessed overflows.
文摘The traditional methods of storm sewers design must be supplemented by a precise and systematic analysis of the consequences of urbanization. This will ensure the reduction of the negative effects of urbanization in the process of stormwater sewer system normal functioning. As the urbanization of rural areas has been in constant progress, there was a need for the development of infrastructure system of urban planning documents that accompany urbanization. Surface storage appears to be one of the solutions that can have positive effects on the consequences of rapid urbanization in terms of preserving water quality of recipients, as well as opportunities to reduce the diameter of drain pipes downstream of surface storage. The necessary investments do not exceed the values of conventional technologies and procedures that are used for this purpose. The restriction of application of these methods is reflected in the limited space, especially in the smaller urban areas, where urbanization was a sudden and uncontrolled process. Future planning documents must contain alternatives like these, while the reservation of required space must be included in the planning documents in which the treatment of further development of the city will be found.
文摘The projection for groundwater states that the total domestic water demand for greater Bangalore would increase from 1,170 MLD in 2010 to 1,336 MLD in 2016. Dependence on groundwater is ever increasing due to rapid Industrialization & Urbanization. It is estimated that almost 40% of the population of Bangalore is dependent on groundwater. Due to the unscientific disposal of domestic and industrial waste generated, groundwater is getting highly polluted in the city. The scale of this impact will depend mainly upon the water-service infrastructure, the superficial geology and the regional setting. The quality of ground water is equally important as that of quantity. Jointed and fractured granites and gneisses constitute the major aquifer system of BBMP (Bruhat Bengaluru Mahanagara Palike) area. Two new observatory borewells were drilled and lithology report has been prepared. Petrographic Analysis (XRD/XRF) and Water Quality Analysis were carried out as per the standard methods. Petrographic samples were analysed by collecting chip of rock from the borewell for every 20 ft depth, most of the samples were similar and samples were identified as Biotite-Gneiss, Schistose Amphibolite. Water quality analysis was carried out for individual chemical parameters for two borewells drilled. The 1st Borewell struck water at 150 ft (total depth-200 ft) & 2nd struck at 740 ft (total depth-960 ft). Five water samples were collected till end of depth in each borewell. Chemical parameter values such as, Total hardness (360-348, 280-320) mg/ltr, Nitrate (12.24-13.5, 45-48) mg/ltr, Chloride (104-90, 70-70) mg/ltr, Fe (0.75-0.09, 1.288-0.312) mg/ltr etc. are calculated respectively. Water samples were analysed from various parts of BBMP covering 750 sq kms, also thematic maps (IDW method) of water quality are generated for these samples for post-monsoon season. The study aims to explore the sub-surface lithological layers and the thickness of weathered zone, which indirectly helps to know the groundwater pollution source near surface water bodies, dug wells, etc. The above data are interpreted for future ground water resources planning and management.
文摘Isotopic tracers and water quality indicators (TDS (Total Dissolved Solid), Cl^- and NO3^-contents) were used to characterize the recharge and control of the quality of groundwater in the alluvial aquifer beneath of the N'djamena city. For this study, a total of 92 waters samples were taken and this included 67 wells, 21 pumps and 4 surface waters. Some groundwater has 6180 and 62H values close to those of the city of N'djamena and/or the Chad river rains. However, all sampled points are below the Global Meteoric Water Line reflecting their evaporated characters. The interpretation of the isotopic tracers highlights that the recharge of the analyzed ground waters may result from two major mechanisms: (1) direct infiltration of local precipitation; (2) lateral inflow of river waters. The upper aquifer is the most vulnerable to pollution, especially during the recharge period. This pollution is due to the leaching of soils during the rainy season and the rise of the groundwater level which accompanies the overflowing of the Chad and causes the leaching of the polluted horizons of the unsaturated zone. In contrast, the lower aquifer has acceptable concentrations of solutes.
基金Sponsored by Science and Technology Program of Ministry of Housing and Urban-Rural Development in 2016(2016-K1-028)School-level Research Program of Jiangsu Vocational Institute of Architectural Technology(JYA317-18)
文摘In recent years, the acceleration of urbanization process results in frequent watedoggingj the decline of groundwater level and frequent urban infiasttucture construction pfoblem. In order to better safeguard complex ecological system and ecological civilization construction in tiie city, and solve the appropriate ratio of water and wetland area to total land area, for water ecological civilization construction in low impact development, the pursuit of water resources sustainability, the pursuit of safety concept, the pursuit of ecological engineeting technology and the pursuit of art are proposed. Based on these pursuits, the principles and design methods of campus landscape creation in colleges and univefsities under the concept of elow impact^ is analyzed. Taking the landscape design, of the shated training base from Jiangsu Vocational Institute of Architectural Technology as an example, how to use the concept of clow impacf? development in actual cases is analyze4 to achieve rainwater collection, water purification, water storage and rainwater ecological utilization, and create a holistic, ecological and diverse sustainable landscape in colleges and universities.
文摘The drinking water for all the inhabitants of Tangier is still an aim far from being achieved. Therefore, all rural areas and some urban areas feed water wells and springs whose composition and safety are unknown. In the absence of data on water and ignorance of consumers towards the risk of poisoning and waterborne diseases transmitted by these waters, the authors conducted a study to determine the composition, physico-chemical quality and bacteriological these waters. This study is to provide a basic physico-chemical and bacteriological data from these waters in some urban areas of old or missing infrastructure in some sites in the province of Tangier. Such as Ziatine sites, Gzenaya, Rmilate, Malabata + Mnar, Mghoura + Aouama and Downtown. Analyzes are performed according to AFNOR methods (AFNOR: French Standards Association). The results indicate that these waters are generally mild and are experiencing significant geochemical imbalance. Moreover, these waters also have a significant organic and bacteriological pollution. It is concluded that the waters of these sites are of poor quality, unfit for human consumption.
文摘This paper aims to quantitatively assess water losses of Badovc Lake-Kosovo based on both water balance of the lake and water hydrochemistry. This attempt was strongly prompt by both the importance of this lake for water supply of Prishtina city and the lack of water. According to lake water balance, a water loss of 3,738,905 m^3 and 1,722,552 m^3 for the hydrologic year 2014 and the period January-May (2015) was evaluated. These consistent data favour the opinion that a continuous groundwater outflow from the lake is present and it is conditioned by the intensively developed fracture system in the lake basement formations. This was also supported by the chemical data (chloride, sulphate, hardness and electric conductivity etc.) of the water. Water from the leakages on the right side of the dam shows the same chemical signature as the water from the lake. Whereas, water from the piezometer, monitoring well and the gallery of Hajvalia mine show similar values with those of the water from the lake. The calculations of the chloride mass balance showed that the fractions of lake and rainfall waters in the water mixture of Hajvalia mine were 67% and 33% respectively.
基金Projects(51039001,51009063) supported by the National Natural Science Foundation of ChinaProject(SX2010-026) supported by State Council Three Gorges Project Construction Committee Executive Office,China+1 种基金Project(2012BS046) supported by Henan University of Technology,ChinaProject(BYHGLC-2010-02) supported by the Guangzhou Water Authority,China
文摘An integrated evaluation system under randomness and fuzziness was developed in this work to systematically assess the risk of groundwater contamination in a little town, Central China. In this system, randomness of the parameters and the fuzziness of the risk were considered simultaneously, and the exceeding standard probability of contamination and human health risk due to the contamination were integrated. The contamination risk was defined as a combination of "vulnerability" and "hazard". To calculate the value of "vulnerability", pollutant concentration was simulated by MODFLOW with random input variables and a new modified health risk assessment(MRA) model was established to analyze the level of "hazard". The limit concentration based on environmental-guideline and health risk due to manganese were systematically examined to obtain the general risk levels through a fuzzy rule base. The "vulnerability" and "hazard" were divided into five categories of "high", "medium-high", "medium", "low-medium" and "low", respectively. Then, "vulnerability" and "hazard" were firstly combined by integrated evaluation. Compared with the other two scenarios under deterministic methods, the risk obtained in the proposed system is higher. This research illustrated that ignoring of uncertainties in evaluation process might underestimate the risk level.
文摘The research centered on the groundwater quality parameters in five boreholes and three wells in residential urban areas of Zimbabwe. Ten runs of chemical analysis for water pH, EC (electrical conductivity), water hardness were carried out weekly and averages were calculated for each at Bindura University laboratory. Iron concentrations analysis was done at the Tobacco Research Station. The results from boreholes and wells were compared to the WHO (World Health Organisation) drinking water acceptable standards to measure the deviations. It was found that the boreholes had hard waters (112 mg/L), EC (425 s/m) and iron concentration (0.49 ppm) outside the WHO standards (〉 64 mg/L; 400 s/m; 0.3 ppm respectively). In contrary the wells had only the water pH slightly outside the acceptable ranges (5.8); other parameters were in the acceptable ranges (EC 379 s/m; water hardness 0.38 mg/L as CaCO3 and iron concentration 0.38 ppm). The difference in chemical composition between the boreholes and wells caused the borehole water rejection in favor of well water. High iron concentrations and water hardness in boreholes were major contributors to the water rejection by the residents.
文摘Groundwater is the water located beneath the earth's surface in the soil pore spaces and in the fractures of rock formations. As one of the most important natural resources, groundwater is associated with the environment, public health, welfare, and long-term economic growth, which affects the daily activities of human beings. In modern urban areas, the primary contaminants of groundwater are artificial products, such as gasoline and diesel. To protect this important water resource, a series of efforts have been exerted, including enforcement and remedial actions. Each year, the TGPC (Texas Groundwater Protection Committee) in US publishes a "Joint Groundwater Monitoring and Contamination Report" to describe historic and new contamination cases in each county, which is an important data source for the design of prevention strategies. In this paper, a DDM (data dependent modeling) approach is proposed to predict county-level NCC (new contamination cases). A case study with contamination information from Harris County in Texas was conducted to illustrate the modeling and prediction process with promising results. The one-step prediction error is 1.5%, while the two-step error is 12.1%. The established model can be used at the county-level, state-level, and even at the country-level. Besides, the prediction results could be a reference during decision-making processes.
基金Acknowledgments: This work is keystone items of Ministry of Education P.R.C (No. [2003]77), National Natural Science Foundation of China (No. 40062002), Natural Science Foundation of Guangxi (Nos. 0447001, 0249010, 0575019, 0779012, 0632006-1B, RC2007001) and Department of Water Resources of Guangxi (No. [2004]4).
文摘In the process of city construction, as a comprised factor of city geological environment, underground water takes the most active part, and its dynamic change is fiercest. The city construction unceasingly disturbs underground water chemical, dynamical, physical and biological field. In return, the four fields' changes also can affect the geological environment that city lived by, in other words they affect safety and stability of geological environment. Interaction of underground water and the geoenvironment directly displays in the following two ways: The first is that the underground water and the geological body transfer the energy each other; the second is that the strength balance of geological body is broken. Underground water variation brought about by city construction is the factor which cannot be neglected. Underground water variation on the one hand changes soils or rocks' physical, biological, chemical and mechanical properties, then influences the deformation and strength of geological body. On the other hand it changes its own physical, chemical properties and biochemical component. At present, from mechanics aspect, interaction between chemical field and biological field variation of the underground water and the geological body lacks research. Although interaction between them is long-term, slow, but when it compared with water-soil or water-rock interaction in the entire process of formation of rocks or soils or geologic evolution history, the qualitative change of the biological and chemical action of rocks or soils brought about by city construction is remarkable, in this paper, aiming at underground water biological field factor which is easily neglected by people, it analyzes that underground water biological field affects possible mechanism and approach of properties variation of rocks or soils in city construction, brings forward further research method and development direction have been also proposed.
基金The National Natural Science Foundation of China(41930110)。
文摘The judicious use and management of natural resources is vital to achieve sustainable development.Land and water are prime natural resources,and their depletion and degradation can lead to serious threats like land subsidence.Land subsidence is a phenomenon of the alteration of elevation at a point on the earth through the sinking of the surface.It occurs when the earth’s surface loses its support.The major causes of land subsidence include groundwater extraction,mining,construction overload,and other similar factors that increase pressure on the surface and eventually subsidize the land.Urban centers with excessive groundwater extraction and infrastructure development are at a high risk of subsidence.Lahore,the second-largest city in Pakistan,is undergoing an enormous increase in population density,uncontrolled urbanization with very large-scale construction projects,and intensive groundwater extraction which are responsible for subsidence directly or indirectly.Therefore,studies on groundwater status and unplanned urban appraisals have seriously urged monitoring of the subsidence in Lahore.Herein,we used freely available Sentinel-1 data for one year(from August 2018 to August 2019),with a high spatial and temporal resolution,to monitor subsidence in Lahore.The data were processed using the SNAP/Sta MPS approach for Persistent Scatterer Interferometric Synthetic Aperture Radar(PSI)analysis,which is an advanced InSAR technique.The displacement velocity map from InSAR processing shows a significant land deformation in the area with values ranging from-114 to 15 mm yr^(-1).Along with the Sentinel-1 data,we also used supplementary data obtained from various government agencies of Pakistan to study the land cover map,transportation network and waterways of Lahore,soil types,population density,and field points for assessing the results and understanding the roles of various factors in the occurrence of uplift or subsidence.A strong correlation was established between subsidence and various parameters such as groundwater extraction and lowering of the water table,soil type variations,land cover changes,surface water channels,and population density.The deformation map confirms the greatest subsidence in the central part of Lahore,while the uplift is observed in the less populated and rural areas situated near Ravi River.The land subsidence and uplift could be attributed to groundwater extraction and recharge through the canal system and the river,respectively.