Identification of groundwater potential areas(GPA)is important in regions facing surface water scarcity,as it assists in effective planning and utilization of groundwater for various purposes.This study employs the me...Identification of groundwater potential areas(GPA)is important in regions facing surface water scarcity,as it assists in effective planning and utilization of groundwater for various purposes.This study employs the methods of remote sensing(RS),geographic information system(GIS)model,and analytical hierarchy process(AHP),multi-criteria decision analysis(MCDA)to locate and map the prospective groundwater areas in the Kulfo-Hare watershed.Seven significant groundwater influencing factors were selected for the determination of groundwater potential in the area:Geology,land use/land cover(LULC),soil,rainfall,slope,drainage density,and lineament density.By applying a five-class classification scheme(very low,low,moderate,high,and very high),the GIS models were used to define the distribution of groundwater potential areas in terms of area coverage(km^(2)),percentage and mapping.The results show that the groundwater potential(GWP)distribution in the research region is as follows:9.7%(6035.9 ha)classified as very high GWP,29.6%(18606 ha)classified as high,24.5%(15245 ha)classified as moderate,18.1%(11431 ha)as low and 18.1%(11492 ha)very low GWP,on the basis of the weighted overlay evaluation.Although a few regions are identifies as extremely low GWP,most of the study area is characterized by very high to moderate GWP.These findings provide valuable insight for sustainable groundwater planning by the government bodies,decision-makers,and private sectors.展开更多
In the basement of southwestern Niger, weathering and fractured zones concentrate most of the groundwater. This study focuses on fractured media and aims to identify areas of productivity in this aquifer to improve th...In the basement of southwestern Niger, weathering and fractured zones concentrate most of the groundwater. This study focuses on fractured media and aims to identify areas of productivity in this aquifer to improve the region’s water coverage. The cartographic approach developed made it possible to establish synthetic maps based on multi-criteria analysis. The hydrogeological parameters selected include fracturing data, drainage system, slope and piezometric level as well as shallow and deep lithology. The choice of these criteria is based on their physical meaning but also on the availability of data. The integration of all the criteria in a GIS allowed to generate maps of recharge and potential productivity of fractured aquifers in the area. The validation of these thematic maps with independent data confirms their utility as reference standards for accessibility for future resource exploitation. Like any spatialization tool, potential recharge maps will provide valuable information about areas where infiltration is more important, and help control and manage risk zoning. The upward evacuation effect is even more prominent along the lineaments, faults or fractures: thus, to avoid possible pollution and to locate the future hydraulic structures, the analysis of the potential recharge zones remains necessary. The potential productivity index map, in addition to the very punctual sites identified by the fracturing study, made it possible to define areas of high potential productivity.展开更多
Irrigation water became the limiting factor to the persistent improvement of grain production. Based on the data from Gannan County, a semiarid area in the west of Heilongjiang Province, the present situation of the d...Irrigation water became the limiting factor to the persistent improvement of grain production. Based on the data from Gannan County, a semiarid area in the west of Heilongjiang Province, the present situation of the development and utilization of water resources and the suitable water saving irrigation mode were analyzed by using SPA model, which was significant to the efficient and rational utilization of water resources and the improvement of agriculture productivity. The result showed that the model could be applied well to the assessment of development and utilization of water resources and the multi-project optimal selection. Through calculation, it could be found that the utilization of water resources in Gannan County was still in the primary stage, and the integration technology of the optimized water saving irrigation should be combined to support the sustainable development of agriculture in the semiarid area.展开更多
Appropriate quantification and identification of the groundwater distribution in a hydrological basin may provide necessary information for effective management,planning and development of groundwater resources.Ground...Appropriate quantification and identification of the groundwater distribution in a hydrological basin may provide necessary information for effective management,planning and development of groundwater resources.Groundwater potential assessment and delineation in a highly heterogeneous environment with limited Spatiotemporal data derived from Gelana watershed of Abaya Chamo lake basin is performed,using integrated multi-criteria decision analysis(MCDA),water and energy transfer between soil and plant and atmosphere under quasi-steady state(WetSpass)models.The outputs of the WetSpass model reveal a favorable structure of water balance in the basin studied,mainly using surface runoff.The simulated total flow and groundwater recharge are validated using river measurements and estimated baseflow at two gauging stations located in the study area,which yields a good agreement.The WetSpass model effectively integrates a water balance assessment in a geographical information system(GIS)environment.The WetSpass model is shown to be computationally reputable for such a remote complex setting as the African rift,with a correlation coefficient of 0.99 and 0.99 for total flow and baseflow at a significant level of p-value<0.05,respectively.The simulated annual water budget reveals that 77.22%of annual precipitation loses through evapotranspiration,of which 16.54%is lost via surface runoff while 6.24%is recharged to the groundwater.The calibrated groundwater recharge from the WetSpass model is then considered when determining the controlling factors of groundwater occurrence and formation,together with other multi-thematic layers such as lithology,geomorphology,lineament density and drainage density.The selected five thematic layers through MCDA are incorporated by employing the analytical hierarchy process(AHP)method to identify the relative dominance in groundwater potential zoning.The weighted factors in the AHP are procedurally aggregated,based on weighted linear combinations to provide the groundwater potential index.Based on the potential indexes,the area then is demarcated into low,moderate,and high groundwater potential zones(GWPZ).The identified GWPZs are finally examined using the existing groundwater inventory data(static water level and springs)in the region.About 70.7%of groundwater inventory points are coinciding with the delineated GWPZs.The weighting comparison shows that lithology,geomorphology,and groundwater recharge appear to be the dominant factors influence on the resources potential.The assessment of groundwater potential index values identify 45.88%as high,39.38%moderate,and 14.73%as low groundwater potential zones.WetSpass model analysis is more preferable in the area like Gelana watershed when the topography is rugged,inaccessible and having limited gauging stations.展开更多
This study investigates the values of pH,total dissolved solids(TDS),elevation,oxidative reduction potential(ORP),temperature,and depth,while the concentrations of Br,and potentially harmful metals(PHMs)such as Cr,Ni,...This study investigates the values of pH,total dissolved solids(TDS),elevation,oxidative reduction potential(ORP),temperature,and depth,while the concentrations of Br,and potentially harmful metals(PHMs)such as Cr,Ni,Cd,Mn,Cu,Pb,Co,Zn,and Fe in the groundwater samples.Moreover,geographic information system(GIS),XLSTAT,and IBM SPSS Statistics 20 software were used for spatial distribution modeling,principal component analysis(PCA),cluster analysis(CA),and Quantile-Quantile(Q-Q)plotting to determine groundwater pollution sources,similarity index,and normal distribution reference line for the selected parameters.The mean values of pH,TDS,elevation,ORP,temperature,depth,and Br were 7.2,322 mg/L,364 m,188 mV,29.6℃,70 m,0.20 mg/L,and PHMs like Cr,Ni,Cd,Mn,Cu,Pb,Co,Zn,and Fe were 0.38,0.26,0.08,0.27,0.36,0.22,0.04,0.43 and 0.86 mg/L,respectively.PHMs including Cr(89%),Cd(43%),Mn(23%),Pb(79%),Co(20%),and Fe(91%)exceeded the guideline values set by the world health organization(WHO).The significant R^(2)values of PCA for selected parameters were also determined(0.62,0.67,0.78,0.73,0.60,0.87,-0.50,0.69,0.70,0.74,-0.50,0.70,0.67,0.79,0.59,and-0.55,respectively).PCA revealed three geochemical processes such as geogenic,anthropogenic,and reducing conditions.The mineral phases of Cd(OH)_(2),Fe(OH)_(3),FeOOH,Mn_(3)O_(4),Fe_(2)O_(3),MnOOH,Pb(OH)_(2),Mn(OH)_(2),MnO_(2),and Zn(OH)_(2)(-3.7,3.75,9.7,-5.8,8.9,-3.6,2.2,-4.6,-7.7,-0.9,and 0.003,respectively)showed super-saturation and under-saturation conditions.Health risk assessment(HRA)values for PHMs were also calculated and the values of hazard quotient(HQ),and hazard indices(HI)for the entire study area were increased in the following order:Cd>Ni>Cu>Pb>Mn>Zn>Cr.Relatively higher HQ and HI values of Ni,Cd,Pb,and Cu were greater than one showing unsuitability of groundwater for domestic,agriculture,and drinking purposes.The long-term ingestion of groundwater could also cause severe health concerns such as kidney,brain dysfunction,liver,stomach problems,and even cancer.展开更多
The southern regions of Madagascar have the country’s lowest water supply coverage and are highly vulnerable to drought.Access to potable drinking water is a major challenge for the local population.Chronic droughts ...The southern regions of Madagascar have the country’s lowest water supply coverage and are highly vulnerable to drought.Access to potable drinking water is a major challenge for the local population.Chronic droughts lead to annual emergency appeals to save the lives of acute malnourished children.UNICEF’s response consisting in providing potable drinking water through the drilling of boreholes has been challenged by the complex hydrogeology,the low yield of boreholes and high-level salinity of water,the lack of reliable groundwater data and the weak capacity of the drilling sector.These constraints result in a high rate of drilling failure.To improve drilling success and provide more potable drinking water to local communities,it is vital to undertake reliable groundwater investigation.UNICEF Madagascar and the European Union delegation in Madagascar collaborated on the use of satellite imagery to improve sector knowledge and access to safe and clean water for local communities in southern Madagascar.The methodology relies on produce thematic layers of groundwater potential areas.Later,these thematic layers were overlaid with ground-based hydrogeological data to map the groundwater potential zones(GWP) and identify the most suitable sites for borehole siting and drilling.Findings of this study are very encouraging,and the integrated approach used has proven its applicability in mapping groundwater potential areas in the eight drought-affected areas of south Madagascar.The groundwater potential zone map is being used by UNICEF and partners to plan water supply projects and identify the best sites for positioning new boreholes and reduce the likelihood of drilling failure.Additionally,the project developed a database of groundwater resources,which will improve knowledge of the regional hydrogeological context and strengthen the capacity of the water sector.Lessons learnt from this study show that an integration of the groundwater potential zone map with demographics and water demand information will help identifying priority areas for detailed studies.Moreover,a capacity building activity is required for knowledge/technology transfer to the Ministry of Energy,Water and Hydrocarbons(MEEH),allowing the possibility of scaling-up this integrated approach to the rest of Madagascar.Finally,strengthening the capacity of the MEEH and refining this approach as suggested above will certainly help in the pursuit to improve equitable access to safe and clean water for households located in the drought-affected areas of southern Madagascar,allowing them to be more resilient to the effects of climate change.展开更多
Water scarcity is the major problem in India where the population has been tremendously increasing, which results in invading natural resources, thus affects on hydrological processes. Because of this, significant sur...Water scarcity is the major problem in India where the population has been tremendously increasing, which results in invading natural resources, thus affects on hydrological processes. Because of this, significant surface water bodies have been disappearing continuously. Therefore, more pressure on groundwater resources is a consequence of that. The integration of remote sensing and geographical information system (GIS), which helps in groundwater research for the investigation of potential groundwater availability, is essential to assess, monitor, and conserve groundwater resources. This analysis reports on the mapping of various potential groundwater resources in the Kolleru Lake catchment, India, by using remote sensing and GIS techniques. For this, a survey of India toposheets and IRC-1C satellite imageries was used to prepare thematic layers of geomorphology, drainage density, lineament, slope, land-use, soil, rainfall, and NDVI converted into raster format in ArcGIS. The raster maps of these thematic layers were assigned to a weight-based factor depending on the catchment characteristics and its topographic influence. The results demonstrated that about 7% of the area is under excellent groundwater potential recharge. Good, moderate, and lower potential conditions are 42%, 38%, and 13%, respectively. The results indicated that the management of groundwater potential zones should be targeted on the middle-catchment region. Further, the results were validated with the borehole data obtained from the Government of Andhra Pradesh-Groundwater Department. These results are useful for better both planning and groundwater management sources in the Kolleru Lake catchment.展开更多
The present study focuses on the use of remote sensing and geographical information system tools for morphometric and geomorphic analysis of major river basins across the Katrol Hill Fault, which makes drainage divide...The present study focuses on the use of remote sensing and geographical information system tools for morphometric and geomorphic analysis of major river basins across the Katrol Hill Fault, which makes drainage divide. It aims to find groundwater potential for the management and planning of groundwater resources. The study area consists of 6 major watersheds of major river systems namely Bhurud, Khari, and Pat flowing north of the major divide, while Rukmawati, Nagavanti, and Bhukhi are southerly flowing rivers. Based on linear, areal, and geomorphic aspects, a watershed with excellent groundwater potential was found. The highest order in the area is the 5th order stream. Appropriate drainage network characteristics, elongated shape, and permeable lithological formation with low relief among all the watersheds made WS3 be excellent potential for groundwater. The statistical analysis, where Cp value was computed, showed the potential groundwater zone to be in WS3 followed by WS2 and WS5. These results were even verified with field data, collected from well-inventory and that too favored WS3 as an excellent groundwater potential.展开更多
There exists a growing demand for potable water resources to fill the abysmally insufficient water needs for domestic and industrial especially in the Basement Complex terrains of Nigeria. This situation is attributab...There exists a growing demand for potable water resources to fill the abysmally insufficient water needs for domestic and industrial especially in the Basement Complex terrains of Nigeria. This situation is attributable to its complex hydrogeologic character. The present challenge has worsened due to the non-incorporation of integrated methods in groundwater exploration campaigns. To effectively combat the challenge of unacceptable failure rates in drilled water well development, there is a need for innovative scientific principles and quantitative assessment of groundwater resources to enhance sustainable and proper utilisation of these resources. Hence, it is the objective of this research to exploit the potential application of remote sensing, Geographic Information System (GIS), and Multi-Criteria Decision Analysis (MCDA) techniques and freely open datasets in mapping groundwater potential zones. Seven thematic maps have been produced based on factors that are deemed to influence and deemed to have significant control on the occurrence and movement of groundwater. These factors are geology, lineament density, slope, drainage density, rainfall, land-use/land cover, and soil class. Analytic Hierarchy Process (AHP) was used to assign normalised weights to the thematic maps based on the various relative contributions to groundwater occurrence and movement. These thematic maps were then processed in a GIS environment using the Weighted Overlay tool which implements the MCDA. The resulting Groundwater Potential Zones (GPZ) of the area gave rise to Five classes viz: Very good, Good, Moderate, Poor and Very Poor </span><span style="font-family:Verdana;">representing 19%, 8%, 14%, 47% and 13% respectively. It is recommended that the GPZ map should be used as a reconnaissance tool for selecting prospective sites for detailed groundwater resource exploitation.展开更多
In this study, an integrated approach was implemented using Geographic Information System (GIS) and Remote Sensing technique for locating promising areas for groundwater exploration. This method is based evaluating a ...In this study, an integrated approach was implemented using Geographic Information System (GIS) and Remote Sensing technique for locating promising areas for groundwater exploration. This method is based evaluating a set of hydrological, geological and topographical parameters that influence the natural occurrence of groundwater. As a result, a ground water potential map (GPM) was generated by modeling these parameters. Groundwater potential map results were classified into three classes that describe the potentiality of each cell in the study area for groundwater exploration. These classes are;high, moderate and low groundwater potential area. It was found that about 7% of the study was classified as high potential areas which were found to be concentrated in the western part of the study area. About 79% of the study was classified as moderate potential for groundwater exploration. The rest of the study area (14%) was classified as low potential areas and concentrated in northeast and southeast part of the study area. These results were verified against existing well data and field observations. Furthermore, a sensitivity analysis was performed to study the effect of each parameter on the overall groundwater map using the effective weight and variation index. It was found that the slope parameter was the most effective among the five used parameters in the model.展开更多
Groundwater resources have always been some of the most valuable resources of human settlements.Climate changes and ever-increasing water demands registered in the last century have led to diminishing levels of ground...Groundwater resources have always been some of the most valuable resources of human settlements.Climate changes and ever-increasing water demands registered in the last century have led to diminishing levels of groundwater reserves,as well as reduced recharging potential.Therefore,in order to use groundwater aquifers in a sustainable manner,it is required to identify areas with higher replenishing potential.The current study addresses the issue of generating a map for identifying differently ranked groundwater recharging potential values,in the aquifers of the Moldavian Plain region,Romania.For the purpose of conducting the analysis,maps were created through GIS based multi-criteria Analytic Hierarchy Process(AHP)and Catastrophe Theory(CT),with seven relevant,thematic,spatial layers:precipitation distribution,lithological strata,soil texture,declivity,drainage density,land use and the distribution of groundwater level tendencies.The results of the two methods of analysis are similar.Prediction differences are of maximum 3%,in the case of extreme classes(very bad and very good)and in the case of middle classes the deviation is not greater than 0.4%.Following the validation of the results generated by the two methods that were applied,it was observed that the predictions offered by CT are more accurate.This aspect can be based on the fact that the main factors that contribute to the prediction are different.This type of workflow emphasizes the necessity of implementing appropriate groundwater management plans for mitigating reservoir scarcity/depletion,and recommending sustainable solutions for future groundwater exploitation practices.展开更多
文摘Identification of groundwater potential areas(GPA)is important in regions facing surface water scarcity,as it assists in effective planning and utilization of groundwater for various purposes.This study employs the methods of remote sensing(RS),geographic information system(GIS)model,and analytical hierarchy process(AHP),multi-criteria decision analysis(MCDA)to locate and map the prospective groundwater areas in the Kulfo-Hare watershed.Seven significant groundwater influencing factors were selected for the determination of groundwater potential in the area:Geology,land use/land cover(LULC),soil,rainfall,slope,drainage density,and lineament density.By applying a five-class classification scheme(very low,low,moderate,high,and very high),the GIS models were used to define the distribution of groundwater potential areas in terms of area coverage(km^(2)),percentage and mapping.The results show that the groundwater potential(GWP)distribution in the research region is as follows:9.7%(6035.9 ha)classified as very high GWP,29.6%(18606 ha)classified as high,24.5%(15245 ha)classified as moderate,18.1%(11431 ha)as low and 18.1%(11492 ha)very low GWP,on the basis of the weighted overlay evaluation.Although a few regions are identifies as extremely low GWP,most of the study area is characterized by very high to moderate GWP.These findings provide valuable insight for sustainable groundwater planning by the government bodies,decision-makers,and private sectors.
文摘In the basement of southwestern Niger, weathering and fractured zones concentrate most of the groundwater. This study focuses on fractured media and aims to identify areas of productivity in this aquifer to improve the region’s water coverage. The cartographic approach developed made it possible to establish synthetic maps based on multi-criteria analysis. The hydrogeological parameters selected include fracturing data, drainage system, slope and piezometric level as well as shallow and deep lithology. The choice of these criteria is based on their physical meaning but also on the availability of data. The integration of all the criteria in a GIS allowed to generate maps of recharge and potential productivity of fractured aquifers in the area. The validation of these thematic maps with independent data confirms their utility as reference standards for accessibility for future resource exploitation. Like any spatialization tool, potential recharge maps will provide valuable information about areas where infiltration is more important, and help control and manage risk zoning. The upward evacuation effect is even more prominent along the lineaments, faults or fractures: thus, to avoid possible pollution and to locate the future hydraulic structures, the analysis of the potential recharge zones remains necessary. The potential productivity index map, in addition to the very punctual sites identified by the fracturing study, made it possible to define areas of high potential productivity.
基金Supported by Heilongjiang Province Technological and Scientific Research Project(12531051)
文摘Irrigation water became the limiting factor to the persistent improvement of grain production. Based on the data from Gannan County, a semiarid area in the west of Heilongjiang Province, the present situation of the development and utilization of water resources and the suitable water saving irrigation mode were analyzed by using SPA model, which was significant to the efficient and rational utilization of water resources and the improvement of agriculture productivity. The result showed that the model could be applied well to the assessment of development and utilization of water resources and the multi-project optimal selection. Through calculation, it could be found that the utilization of water resources in Gannan County was still in the primary stage, and the integration technology of the optimized water saving irrigation should be combined to support the sustainable development of agriculture in the semiarid area.
文摘Appropriate quantification and identification of the groundwater distribution in a hydrological basin may provide necessary information for effective management,planning and development of groundwater resources.Groundwater potential assessment and delineation in a highly heterogeneous environment with limited Spatiotemporal data derived from Gelana watershed of Abaya Chamo lake basin is performed,using integrated multi-criteria decision analysis(MCDA),water and energy transfer between soil and plant and atmosphere under quasi-steady state(WetSpass)models.The outputs of the WetSpass model reveal a favorable structure of water balance in the basin studied,mainly using surface runoff.The simulated total flow and groundwater recharge are validated using river measurements and estimated baseflow at two gauging stations located in the study area,which yields a good agreement.The WetSpass model effectively integrates a water balance assessment in a geographical information system(GIS)environment.The WetSpass model is shown to be computationally reputable for such a remote complex setting as the African rift,with a correlation coefficient of 0.99 and 0.99 for total flow and baseflow at a significant level of p-value<0.05,respectively.The simulated annual water budget reveals that 77.22%of annual precipitation loses through evapotranspiration,of which 16.54%is lost via surface runoff while 6.24%is recharged to the groundwater.The calibrated groundwater recharge from the WetSpass model is then considered when determining the controlling factors of groundwater occurrence and formation,together with other multi-thematic layers such as lithology,geomorphology,lineament density and drainage density.The selected five thematic layers through MCDA are incorporated by employing the analytical hierarchy process(AHP)method to identify the relative dominance in groundwater potential zoning.The weighted factors in the AHP are procedurally aggregated,based on weighted linear combinations to provide the groundwater potential index.Based on the potential indexes,the area then is demarcated into low,moderate,and high groundwater potential zones(GWPZ).The identified GWPZs are finally examined using the existing groundwater inventory data(static water level and springs)in the region.About 70.7%of groundwater inventory points are coinciding with the delineated GWPZs.The weighting comparison shows that lithology,geomorphology,and groundwater recharge appear to be the dominant factors influence on the resources potential.The assessment of groundwater potential index values identify 45.88%as high,39.38%moderate,and 14.73%as low groundwater potential zones.WetSpass model analysis is more preferable in the area like Gelana watershed when the topography is rugged,inaccessible and having limited gauging stations.
基金financially supported National Natural Science Foundation of China(Grant Nos.41521001 and 41877204)the 111 Program(State Administration Foreign Experts Affairs&the Ministry of Education of China,Grant No.B18049)the China Postdoctoral Science Foundation(Grant No.2018M642944)。
文摘This study investigates the values of pH,total dissolved solids(TDS),elevation,oxidative reduction potential(ORP),temperature,and depth,while the concentrations of Br,and potentially harmful metals(PHMs)such as Cr,Ni,Cd,Mn,Cu,Pb,Co,Zn,and Fe in the groundwater samples.Moreover,geographic information system(GIS),XLSTAT,and IBM SPSS Statistics 20 software were used for spatial distribution modeling,principal component analysis(PCA),cluster analysis(CA),and Quantile-Quantile(Q-Q)plotting to determine groundwater pollution sources,similarity index,and normal distribution reference line for the selected parameters.The mean values of pH,TDS,elevation,ORP,temperature,depth,and Br were 7.2,322 mg/L,364 m,188 mV,29.6℃,70 m,0.20 mg/L,and PHMs like Cr,Ni,Cd,Mn,Cu,Pb,Co,Zn,and Fe were 0.38,0.26,0.08,0.27,0.36,0.22,0.04,0.43 and 0.86 mg/L,respectively.PHMs including Cr(89%),Cd(43%),Mn(23%),Pb(79%),Co(20%),and Fe(91%)exceeded the guideline values set by the world health organization(WHO).The significant R^(2)values of PCA for selected parameters were also determined(0.62,0.67,0.78,0.73,0.60,0.87,-0.50,0.69,0.70,0.74,-0.50,0.70,0.67,0.79,0.59,and-0.55,respectively).PCA revealed three geochemical processes such as geogenic,anthropogenic,and reducing conditions.The mineral phases of Cd(OH)_(2),Fe(OH)_(3),FeOOH,Mn_(3)O_(4),Fe_(2)O_(3),MnOOH,Pb(OH)_(2),Mn(OH)_(2),MnO_(2),and Zn(OH)_(2)(-3.7,3.75,9.7,-5.8,8.9,-3.6,2.2,-4.6,-7.7,-0.9,and 0.003,respectively)showed super-saturation and under-saturation conditions.Health risk assessment(HRA)values for PHMs were also calculated and the values of hazard quotient(HQ),and hazard indices(HI)for the entire study area were increased in the following order:Cd>Ni>Cu>Pb>Mn>Zn>Cr.Relatively higher HQ and HI values of Ni,Cd,Pb,and Cu were greater than one showing unsuitability of groundwater for domestic,agriculture,and drinking purposes.The long-term ingestion of groundwater could also cause severe health concerns such as kidney,brain dysfunction,liver,stomach problems,and even cancer.
基金the support of the Delegation of the European Union of the Republic of Madagascarthe Management of UNICEF Madagascar
文摘The southern regions of Madagascar have the country’s lowest water supply coverage and are highly vulnerable to drought.Access to potable drinking water is a major challenge for the local population.Chronic droughts lead to annual emergency appeals to save the lives of acute malnourished children.UNICEF’s response consisting in providing potable drinking water through the drilling of boreholes has been challenged by the complex hydrogeology,the low yield of boreholes and high-level salinity of water,the lack of reliable groundwater data and the weak capacity of the drilling sector.These constraints result in a high rate of drilling failure.To improve drilling success and provide more potable drinking water to local communities,it is vital to undertake reliable groundwater investigation.UNICEF Madagascar and the European Union delegation in Madagascar collaborated on the use of satellite imagery to improve sector knowledge and access to safe and clean water for local communities in southern Madagascar.The methodology relies on produce thematic layers of groundwater potential areas.Later,these thematic layers were overlaid with ground-based hydrogeological data to map the groundwater potential zones(GWP) and identify the most suitable sites for borehole siting and drilling.Findings of this study are very encouraging,and the integrated approach used has proven its applicability in mapping groundwater potential areas in the eight drought-affected areas of south Madagascar.The groundwater potential zone map is being used by UNICEF and partners to plan water supply projects and identify the best sites for positioning new boreholes and reduce the likelihood of drilling failure.Additionally,the project developed a database of groundwater resources,which will improve knowledge of the regional hydrogeological context and strengthen the capacity of the water sector.Lessons learnt from this study show that an integration of the groundwater potential zone map with demographics and water demand information will help identifying priority areas for detailed studies.Moreover,a capacity building activity is required for knowledge/technology transfer to the Ministry of Energy,Water and Hydrocarbons(MEEH),allowing the possibility of scaling-up this integrated approach to the rest of Madagascar.Finally,strengthening the capacity of the MEEH and refining this approach as suggested above will certainly help in the pursuit to improve equitable access to safe and clean water for households located in the drought-affected areas of southern Madagascar,allowing them to be more resilient to the effects of climate change.
文摘Water scarcity is the major problem in India where the population has been tremendously increasing, which results in invading natural resources, thus affects on hydrological processes. Because of this, significant surface water bodies have been disappearing continuously. Therefore, more pressure on groundwater resources is a consequence of that. The integration of remote sensing and geographical information system (GIS), which helps in groundwater research for the investigation of potential groundwater availability, is essential to assess, monitor, and conserve groundwater resources. This analysis reports on the mapping of various potential groundwater resources in the Kolleru Lake catchment, India, by using remote sensing and GIS techniques. For this, a survey of India toposheets and IRC-1C satellite imageries was used to prepare thematic layers of geomorphology, drainage density, lineament, slope, land-use, soil, rainfall, and NDVI converted into raster format in ArcGIS. The raster maps of these thematic layers were assigned to a weight-based factor depending on the catchment characteristics and its topographic influence. The results demonstrated that about 7% of the area is under excellent groundwater potential recharge. Good, moderate, and lower potential conditions are 42%, 38%, and 13%, respectively. The results indicated that the management of groundwater potential zones should be targeted on the middle-catchment region. Further, the results were validated with the borehole data obtained from the Government of Andhra Pradesh-Groundwater Department. These results are useful for better both planning and groundwater management sources in the Kolleru Lake catchment.
文摘The present study focuses on the use of remote sensing and geographical information system tools for morphometric and geomorphic analysis of major river basins across the Katrol Hill Fault, which makes drainage divide. It aims to find groundwater potential for the management and planning of groundwater resources. The study area consists of 6 major watersheds of major river systems namely Bhurud, Khari, and Pat flowing north of the major divide, while Rukmawati, Nagavanti, and Bhukhi are southerly flowing rivers. Based on linear, areal, and geomorphic aspects, a watershed with excellent groundwater potential was found. The highest order in the area is the 5th order stream. Appropriate drainage network characteristics, elongated shape, and permeable lithological formation with low relief among all the watersheds made WS3 be excellent potential for groundwater. The statistical analysis, where Cp value was computed, showed the potential groundwater zone to be in WS3 followed by WS2 and WS5. These results were even verified with field data, collected from well-inventory and that too favored WS3 as an excellent groundwater potential.
文摘There exists a growing demand for potable water resources to fill the abysmally insufficient water needs for domestic and industrial especially in the Basement Complex terrains of Nigeria. This situation is attributable to its complex hydrogeologic character. The present challenge has worsened due to the non-incorporation of integrated methods in groundwater exploration campaigns. To effectively combat the challenge of unacceptable failure rates in drilled water well development, there is a need for innovative scientific principles and quantitative assessment of groundwater resources to enhance sustainable and proper utilisation of these resources. Hence, it is the objective of this research to exploit the potential application of remote sensing, Geographic Information System (GIS), and Multi-Criteria Decision Analysis (MCDA) techniques and freely open datasets in mapping groundwater potential zones. Seven thematic maps have been produced based on factors that are deemed to influence and deemed to have significant control on the occurrence and movement of groundwater. These factors are geology, lineament density, slope, drainage density, rainfall, land-use/land cover, and soil class. Analytic Hierarchy Process (AHP) was used to assign normalised weights to the thematic maps based on the various relative contributions to groundwater occurrence and movement. These thematic maps were then processed in a GIS environment using the Weighted Overlay tool which implements the MCDA. The resulting Groundwater Potential Zones (GPZ) of the area gave rise to Five classes viz: Very good, Good, Moderate, Poor and Very Poor </span><span style="font-family:Verdana;">representing 19%, 8%, 14%, 47% and 13% respectively. It is recommended that the GPZ map should be used as a reconnaissance tool for selecting prospective sites for detailed groundwater resource exploitation.
文摘In this study, an integrated approach was implemented using Geographic Information System (GIS) and Remote Sensing technique for locating promising areas for groundwater exploration. This method is based evaluating a set of hydrological, geological and topographical parameters that influence the natural occurrence of groundwater. As a result, a ground water potential map (GPM) was generated by modeling these parameters. Groundwater potential map results were classified into three classes that describe the potentiality of each cell in the study area for groundwater exploration. These classes are;high, moderate and low groundwater potential area. It was found that about 7% of the study was classified as high potential areas which were found to be concentrated in the western part of the study area. About 79% of the study was classified as moderate potential for groundwater exploration. The rest of the study area (14%) was classified as low potential areas and concentrated in northeast and southeast part of the study area. These results were verified against existing well data and field observations. Furthermore, a sensitivity analysis was performed to study the effect of each parameter on the overall groundwater map using the effective weight and variation index. It was found that the slope parameter was the most effective among the five used parameters in the model.
基金Romanian Ministry of Education and Research CNCS-UEFISCDI,No.PN-III-P1-1.1-TE-2019-0286,POSCCE-O 2.2.1,SMIS-CSNR 13984-901,No.257/28.09.2010 Project,CERNESIM。
文摘Groundwater resources have always been some of the most valuable resources of human settlements.Climate changes and ever-increasing water demands registered in the last century have led to diminishing levels of groundwater reserves,as well as reduced recharging potential.Therefore,in order to use groundwater aquifers in a sustainable manner,it is required to identify areas with higher replenishing potential.The current study addresses the issue of generating a map for identifying differently ranked groundwater recharging potential values,in the aquifers of the Moldavian Plain region,Romania.For the purpose of conducting the analysis,maps were created through GIS based multi-criteria Analytic Hierarchy Process(AHP)and Catastrophe Theory(CT),with seven relevant,thematic,spatial layers:precipitation distribution,lithological strata,soil texture,declivity,drainage density,land use and the distribution of groundwater level tendencies.The results of the two methods of analysis are similar.Prediction differences are of maximum 3%,in the case of extreme classes(very bad and very good)and in the case of middle classes the deviation is not greater than 0.4%.Following the validation of the results generated by the two methods that were applied,it was observed that the predictions offered by CT are more accurate.This aspect can be based on the fact that the main factors that contribute to the prediction are different.This type of workflow emphasizes the necessity of implementing appropriate groundwater management plans for mitigating reservoir scarcity/depletion,and recommending sustainable solutions for future groundwater exploitation practices.