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Li Wan - One of the best experts on this subject based on the ideXlab platform.
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Flowing Wells: terminology, history and role in the evolution of groundwater science
Hydrology and Earth System Sciences, 2020Co-Authors: Xiao-wei Jiang, John Cherry, Li WanAbstract:Abstract. The gushing of water from Flowing Wells attracted public attention and scientific curiosity as early as the 17th century, but little attention has been paid to the influence of Flowing Wells on the evolution of groundwater science. This study asserts that questions posed by Flowing Wells since the early 19th century led to the birth of many fundamental concepts and principles of physical hydrogeology. Due to the widespread occurrence of Flowing Wells in basins with regional aquitards, there is a long-lasting misconception that Flowing Wells could only occur in regionally confined aquifers. However, the recognition of possible occurrence of Flowing Wells in unconfined aquifers was anticipated at the turn of the 20th century based on observed increases in hydraulic head with depth in topographic lows of basins without apparent aquitards. This was later verified in the 1960s by field and modeling studies that gave birth to quantitative analysis of topographically driven groundwater flow systems, which was a paradigm shift in hydrogeology. Following this paradigm, several preconditions for Flowing Wells established in the 19th century were found unnecessary. Intermingled in the evolution of flow system concepts are inconsistencies and confusion concerning the use of the term “artesian”, so we propose avoidance of this term. This historical perspective of the causes of Flowing well conditions and the influence of Flowing Wells on groundwater science could lead to a deeper understanding of the evolution of groundwater science and guide future studies on hydraulics of Flowing Wells.
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Flowing Wells: history and role as a root of groundwater hydrology
2020Co-Authors: Xiao-wei Jiang, John A. Cherry, Li WanAbstract:Abstract. The spewing of groundwater in Flowing Wells is a phenomenon of interest to the public, but little attention has been paid to the role of Flowing Wells on the science of groundwater. This study reviews that answering to problems related to Flowing Wells since the early 19th century led to the birth of many fundamental concepts and principles of groundwater hydrology. The concepts stemmed from Flowing Wells in confined aquifers include permeability and compressibility, while the principles include Darcy's law, role of aquitards on Flowing well conditions and the piston flow pattern, steady-state well hydraulics in confined aquifers, and transient well hydraulics towards constant-head Wells in confined or leaky aquifers, all of which are applicable even if Flowing well conditions have disappeared. Due to the widespread occurrence of aquitards, there is a long-lasting misconception that Flowing Wells must be geologically-controlled. The occurrence of Flowing Wells in topographic lows of unconfined aquifers was anticipated in 1940 and later verified in the 1960s, accompanying with the birth of the theory of topographically-driven groundwater flow, which has been considered as a paradigm shift in groundwater hydrology. Based on studies following this new paradigm, several preconditions of Flowing Wells given in the 19th century have been found to be not necessary at all. This historical perspective of the causes of Flowing well conditions and the role of Flowing Wells on the science of groundwater could lead to a deeper understanding of the evolution of groundwater hydrology.
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Why mixed groundwater at the outlet of open Flowing Wells in unconfined-aquifer basins can represent deep groundwater: implications for sampling in long-screen Wells
Hydrogeology Journal, 2018Co-Authors: Zhi-yuan Zhang, Xiao-wei Jiang, Li Wan, Xu-sheng Wang, Jun-zhi WangAbstract:Groundwater sampled at the outlets of uncased Flowing Wells in a thick unconfined aquifer, which has undergone mixing, has been found to have hydrochemistry similar to deep groundwater in discharge areas. To identify the hydrodynamic causes, transient models of groundwater flow and age in a three-dimensional homogeneous unit basin with Flowing Wells are constructed to obtain flow rates in Wells and groundwater mean age around Wells. Inflow of groundwater to the well in the deep part leads to mixing of groundwater from different sources, and the finally mixed groundwater is found to have the same age as groundwater in the aquifer at a specific depth, termed the equivalent position (EP). EP is always found in the lower half of the Flowing well, indicating that a mixed sample at the outlet could represent deep groundwater. Outflow from the well to the unconfined aquifer in the shallow part results in aging of groundwater around the well. For fully penetrating Flowing Wells in confined aquifers, EP is found in the upper half of the aquifer. The different relative depths of EP to the screen interval in the two types of Flowing Wells are mainly due to the profiles of horizontal velocity in the inflow segment, which is basically uniform in a confined aquifer but increases from zero to a maximum value in unconfined aquifers. Thus, groundwater at the outlets of topography-controlled Flowing Wells is a window of the deep part of a basin, and existing long-screen Wells could have the potential for groundwater sampling.
Qiuming Cheng - One of the best experts on this subject based on the ideXlab platform.
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Application of Weights of Evidence Method for Assessment of Flowing Wells in the Greater Toronto Area, Canada
Natural Resources Research, 2004Co-Authors: Qiuming ChengAbstract:Flowing Wells extracted from the Ministry of Ontario Environment and Energy (MOEE) water well data set from the Oak Ridges Moraine (ORM) area, Ontario, Canada, were treated as training point set to evaluate the potential distribution of artesian aquifers and their spatial associations with other geological and topological features in the study area. Evidential layers of geological and topographical features were constructed on the basis of the digital elevation model (DEM) and a geological map using GIS buffering functions in conjunction with weights of evidence method. It has been demonstrated that the locations of the Flowing Wells in the Oak Ridges Moraine area are associated spatially with the distances, (a) 500–5000 m from the oak ridges moraine deposits, (b) 500–4000 m from thick drift layer delineated on the drift thickness map created from water well data, and (c) 1500–2500 m from steep slope zones with slope above 8 degree calculated from a DEM. Applying a combination of these conditions can reduce the predicting target areas of having Flowing Wells by two thirds. Outcomes of this research are important both because the impact of the results on understanding of characteristics of aquifers and their relationships with other geological and topographical features and because it generates a probability map showing the potential location of artesian aquifers in the ORM area. In addition, the methodologies used in the paper will be applicable for modeling the distributions of other types of objects such as surface water bodies and low flow of streams in a watershed context in the study area.
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IGARSS - GIS spatial statistical analysis of groundwater in GTA, Canada
IEEE International Geoscience and Remote Sensing Symposium, 1Co-Authors: Zhenghe Zhang, Qiuming ChengAbstract:A number of geological, hydrological, and hydrogeological features related to the aquifers in the Oak Ridges Moraine area extracted from the MOEE water well data, digital geological map, remote sensed Landsat TM images were mapped and analyzed using statistical approaches and GIS. Using the Flowing Wells as training points, the weights of evidence model was applied to describe the spatial pattern of the high yield confined aquifers, and to measure the correlation between the Flowing Wells and the regional hydrogeological features. This has led to the identification of binary evidential features to predicting the potential distributions of confined aquifers. These binary patterns correlated to the locations of Flowing Wells were integrated using multivariate logistic regression model and a predictive map was created to illustrate the potential distributions of confined aquifers in the ORM area. It has been demonstrated that the weights of evidence and logistic regression models implemented in GIS can be used as effective analytical tools to predict the potential of high yield confined aquifers in the study area. The predictive result can be used to interpret the potentia interactions between ground water and surface water system such as river baseflow, ponds and lakes.
Xiao-wei Jiang - One of the best experts on this subject based on the ideXlab platform.
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Flowing Wells: terminology, history and role in the evolution of groundwater science
Hydrology and Earth System Sciences, 2020Co-Authors: Xiao-wei Jiang, John Cherry, Li WanAbstract:Abstract. The gushing of water from Flowing Wells attracted public attention and scientific curiosity as early as the 17th century, but little attention has been paid to the influence of Flowing Wells on the evolution of groundwater science. This study asserts that questions posed by Flowing Wells since the early 19th century led to the birth of many fundamental concepts and principles of physical hydrogeology. Due to the widespread occurrence of Flowing Wells in basins with regional aquitards, there is a long-lasting misconception that Flowing Wells could only occur in regionally confined aquifers. However, the recognition of possible occurrence of Flowing Wells in unconfined aquifers was anticipated at the turn of the 20th century based on observed increases in hydraulic head with depth in topographic lows of basins without apparent aquitards. This was later verified in the 1960s by field and modeling studies that gave birth to quantitative analysis of topographically driven groundwater flow systems, which was a paradigm shift in hydrogeology. Following this paradigm, several preconditions for Flowing Wells established in the 19th century were found unnecessary. Intermingled in the evolution of flow system concepts are inconsistencies and confusion concerning the use of the term “artesian”, so we propose avoidance of this term. This historical perspective of the causes of Flowing well conditions and the influence of Flowing Wells on groundwater science could lead to a deeper understanding of the evolution of groundwater science and guide future studies on hydraulics of Flowing Wells.
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Flowing Wells: history and role as a root of groundwater hydrology
2020Co-Authors: Xiao-wei Jiang, John A. Cherry, Li WanAbstract:Abstract. The spewing of groundwater in Flowing Wells is a phenomenon of interest to the public, but little attention has been paid to the role of Flowing Wells on the science of groundwater. This study reviews that answering to problems related to Flowing Wells since the early 19th century led to the birth of many fundamental concepts and principles of groundwater hydrology. The concepts stemmed from Flowing Wells in confined aquifers include permeability and compressibility, while the principles include Darcy's law, role of aquitards on Flowing well conditions and the piston flow pattern, steady-state well hydraulics in confined aquifers, and transient well hydraulics towards constant-head Wells in confined or leaky aquifers, all of which are applicable even if Flowing well conditions have disappeared. Due to the widespread occurrence of aquitards, there is a long-lasting misconception that Flowing Wells must be geologically-controlled. The occurrence of Flowing Wells in topographic lows of unconfined aquifers was anticipated in 1940 and later verified in the 1960s, accompanying with the birth of the theory of topographically-driven groundwater flow, which has been considered as a paradigm shift in groundwater hydrology. Based on studies following this new paradigm, several preconditions of Flowing Wells given in the 19th century have been found to be not necessary at all. This historical perspective of the causes of Flowing well conditions and the role of Flowing Wells on the science of groundwater could lead to a deeper understanding of the evolution of groundwater hydrology.
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Why mixed groundwater at the outlet of open Flowing Wells in unconfined-aquifer basins can represent deep groundwater: implications for sampling in long-screen Wells
Hydrogeology Journal, 2018Co-Authors: Zhi-yuan Zhang, Xiao-wei Jiang, Li Wan, Xu-sheng Wang, Jun-zhi WangAbstract:Groundwater sampled at the outlets of uncased Flowing Wells in a thick unconfined aquifer, which has undergone mixing, has been found to have hydrochemistry similar to deep groundwater in discharge areas. To identify the hydrodynamic causes, transient models of groundwater flow and age in a three-dimensional homogeneous unit basin with Flowing Wells are constructed to obtain flow rates in Wells and groundwater mean age around Wells. Inflow of groundwater to the well in the deep part leads to mixing of groundwater from different sources, and the finally mixed groundwater is found to have the same age as groundwater in the aquifer at a specific depth, termed the equivalent position (EP). EP is always found in the lower half of the Flowing well, indicating that a mixed sample at the outlet could represent deep groundwater. Outflow from the well to the unconfined aquifer in the shallow part results in aging of groundwater around the well. For fully penetrating Flowing Wells in confined aquifers, EP is found in the upper half of the aquifer. The different relative depths of EP to the screen interval in the two types of Flowing Wells are mainly due to the profiles of horizontal velocity in the inflow segment, which is basically uniform in a confined aquifer but increases from zero to a maximum value in unconfined aquifers. Thus, groundwater at the outlets of topography-controlled Flowing Wells is a window of the deep part of a basin, and existing long-screen Wells could have the potential for groundwater sampling.
Shamsuddin Shahid - One of the best experts on this subject based on the ideXlab platform.
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Flowing well potential zoning at Iraqi southern and western deserts using frequency ratio and geographic information system
International Journal of Environmental Science and Technology, 2017Co-Authors: A. M. Al-abadi, H. B. Ghlaib, Shamsuddin ShahidAbstract:The objective of this study is to integrate geographic information system and bivariate frequency ratio method for the mapping of Flowing well zones in the west and southwest parts of the Euphrates river basin of Iraq. Ten groundwater conditioning factors are identified as controlling factors of groundwater movement based on data availability, literature review, and expert’s opinions. The spatial association between Flowing well locations and groundwater controlling factors is investigated by means of a probabilistic frequency ratio approach. Seventy percent or 148 Wells from an inventory of 211 Flowing Wells in the study area are randomly selected for training, and the remaining 30 or 63% Wells are used for validation of the probabilistic frequency ratio model. The estimated probabilistic ratio values are overlaid and summed to produce the groundwater potential index map. The results reveal that groundwater potential in 128,547 km^2 or 84% of the total area is very low to low. The moderate potential zone covers an area of about 11,210 km^2 or 7%, while the high and very high potential zones are found in an area of 12,982 km^2 or 9% of the study area. Validation of obtaining results by means of a receiver operating characteristic technique reveals that the predictive accuracy of 94% indicating the excellent performance of the proposed approach for spatial zoning of groundwater Flowing well boundary at Iraqi desert.
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Flowing well potential zoning at Iraqi southern and western deserts using frequency ratio and geographic information system
International Journal of Environmental Science and Technology, 2017Co-Authors: Alaa M. Al-abadi, H. B. Ghlaib, Shamsuddin ShahidAbstract:The objective of this study is to integrate geographic information system and bivariate frequency ratio method for the mapping of Flowing well zones in the west and southwest parts of the Euphrates river basin of Iraq. Ten groundwater conditioning factors are identified as controlling factors of groundwater movement based on data availability, literature review, and expert’s opinions. The spatial association between Flowing well locations and groundwater controlling factors is investigated by means of a probabilistic frequency ratio approach. Seventy percent or 148 Wells from an inventory of 211 Flowing Wells in the study area are randomly selected for training, and the remaining 30 or 63% Wells are used for validation of the probabilistic frequency ratio model. The estimated probabilistic ratio values are overlaid and summed to produce the groundwater potential index map. The results reveal that groundwater potential in 128,547 km2 or 84% of the total area is very low to low. The moderate potential zone covers an area of about 11,210 km2 or 7%, while the high and very high potential zones are found in an area of 12,982 km2 or 9% of the study area. Validation of obtaining results by means of a receiver operating characteristic technique reveals that the predictive accuracy of 94% indicating the excellent performance of the proposed approach for spatial zoning of groundwater Flowing well boundary at Iraqi desert.
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Prediction of groundwater Flowing well zone at An-Najif Province, central Iraq using evidential belief functions model and GIS
Environmental Monitoring and Assessment, 2016Co-Authors: Alaa M. Al-abadi, Biswajeet Pradhan, Shamsuddin ShahidAbstract:The objective of this study is to delineate groundwater Flowing well zone potential in An-Najif Province of Iraq in a data-driven evidential belief function model developed in a geographical information system (GIS) environment. An inventory map of 68 groundwater Flowing Wells was prepared through field survey. Seventy percent or 43 Wells were used for training the evidential belief functions model and the reset 30 % or 19 Wells were used for validation of the model. Seven groundwater conditioning factors mostly derived from RS were used, namely elevation, slope angle, curvature, topographic wetness index, stream power index, lithological units, and distance to the Euphrates River in this study. The relationship between training Flowing well locations and the conditioning factors were investigated using evidential belief functions technique in a GIS environment. The integrated belief values were classified into five categories using natural break classification scheme to predict spatial zoning of groundwater Flowing well, namely very low (0.17–0.34), low (0.34–0.46), moderate (0.46–0.58), high (0.58–0.80), and very high (0.80–0.99). The results show that very low and low zones cover 72 % (19,282 km^2) of the study area mostly clustered in the central part, the moderate zone concentrated in the west part covers 13 % (3481 km^2), and the high and very high zones extended over the northern part cover 15 % (3977 km^2) of the study area. The vast spatial extension of very low and low zones indicates that groundwater Flowing Wells potential in the study area is low. The performance of the evidential belief functions spatial model was validated using the receiver operating characteristic curve. A success rate of 0.95 and a prediction rate of 0.94 were estimated from the area under relative operating characteristics curves, which indicate that the developed model has excellent capability to predict groundwater Flowing well zones. The produced map of groundwater Flowing well zones could be used to identify new Wells and manage groundwater storage in a sustainable manner.
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Spatial mapping of artesian zone at Iraqi southern desert using a GIS-based random forest machine learning model
Modeling Earth Systems and Environment, 2016Co-Authors: Alaa M. Al-abadi, Shamsuddin ShahidAbstract:Random forest (RF) machine learning technique and geographical information system (GIS) have been applied to delineate groundwater Flowing well zones in the southern desert of Iraq. A spatial database consists of target variable, i.e., geographic locations of 93 Flowing Wells and predictor variables, i.e., the factors that control groundwater occurrence was prepared for this purpose. Eleven predictor variables were selected based on data availability, literature review, and field conditions which include elevation, slope, profile curvature, aspect, topographic wetness index, stream power index, distance to Abu Jir fault, distance to Euphrates River, major aquifer group, total hydraulic head, and well depth. The RF model in R package along with ArcGIS 10.2 was used to generate groundwater Flowing well potential index for the study area. The obtained potential indices were classified using natural break classification scheme into five categories namely, very low, low, moderate, high, and very high. The results revealed that high or very high groundwater Flowing well potential zones occupy 15 %, moderate potential zone covers 6 %, and low or very low potential zones cover 79 % of the southern desert of Iraq. The groundwater Flowing well zone map was validated using relative operating characteristic (ROC) curve. The areas under the ROC curve for success and prediction rates were 0.98 and 0.97, respectively, indicating excellent capability of RF model to delineate groundwater potential. It is expected that the method development in this study can be used for rapid but efficient evaluation of groundwater Flowing well potential from limited amount of data.
Alaa M. Al-abadi - One of the best experts on this subject based on the ideXlab platform.
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A comparative assessment of fuzzy logic and evidential belief function models for mapping artesian zone boundary in an arid region, Iraq
Journal of Hydroinformatics, 2017Co-Authors: Alaa M. Al-abadi, Suaad A. Al-bhadili, Maitham A. Al-ghanimyAbstract:This paper discusses and compares the potential application of the evidential belief function model and fuzzy logic inference system technique for spatial delineation of a groundwater artesian zone boundary in an arid region of central Iraq. First, a Flowing well inventory of a total of 93 perennial Flowing Wells was constructed and randomly partitioned into two data sets: 70% (65 Wells) for training and 30% (28 Wells) for validation. Twelve groundwater conditioning factors were considered in the geospatial analysis depending on data availability and literature review. The random forest (RF) algorithm was first applied to investigate the most important conditioning factors in groundwater potential analysis. The most important factors with training Flowing Wells were used to develop predictive models. The prediction accuracy of the developed models was checked using the area under the relative operating characteristic curve. Results showed that the best model with a higher prediction accuracy of 86% was a fuzzy AND model followed by the evidential model with 84%. The main conclusion of this study is that the integrated use of the adapted models with RF offer a rapid assessment tool in groundwater exploration and can be helpful in groundwater management.
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A novel geographical information system-based Ant Miner algorithm model for delineating groundwater Flowing artesian well boundary: a case study from Iraqi southern and western deserts
Environmental Earth Sciences, 2017Co-Authors: Alaa M. Al-abadiAbstract:The Ant Miner algorithm was compared with the bivariate frequency ratio (FR) and boosted regression trees (BRT) algorithms in terms of its capacity to assess groundwater potential. A geospatial dataset was prepared that contains two components: a Flowing well inventory map and eleven factors relevant to groundwater conditions. Average nearest neighbor technique was used to investigate the spatial pattern of Flowing Wells and to find the appropriate distance between Flowing and nonFlowing points in the study area. A wrapper approach known as random forest classifier and a filtering approach known as information gain ratio were used to identify the most relevant groundwater factors. The developed models were validated via the area under the operating characteristic curve. Results revealed that the Ant Miner model performed better in terms of both success (0.944) and prediction (0.92) rates compared to FR and BRT. Furthermore, the Ant Miner algorithm derived five simple, easily interpreted rules for predicting groundwater potential that can be used by hydrogeologists for identifying potential groundwater well locations with minimal effort and cost.
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Flowing well potential zoning at Iraqi southern and western deserts using frequency ratio and geographic information system
International Journal of Environmental Science and Technology, 2017Co-Authors: Alaa M. Al-abadi, H. B. Ghlaib, Shamsuddin ShahidAbstract:The objective of this study is to integrate geographic information system and bivariate frequency ratio method for the mapping of Flowing well zones in the west and southwest parts of the Euphrates river basin of Iraq. Ten groundwater conditioning factors are identified as controlling factors of groundwater movement based on data availability, literature review, and expert’s opinions. The spatial association between Flowing well locations and groundwater controlling factors is investigated by means of a probabilistic frequency ratio approach. Seventy percent or 148 Wells from an inventory of 211 Flowing Wells in the study area are randomly selected for training, and the remaining 30 or 63% Wells are used for validation of the probabilistic frequency ratio model. The estimated probabilistic ratio values are overlaid and summed to produce the groundwater potential index map. The results reveal that groundwater potential in 128,547 km2 or 84% of the total area is very low to low. The moderate potential zone covers an area of about 11,210 km2 or 7%, while the high and very high potential zones are found in an area of 12,982 km2 or 9% of the study area. Validation of obtaining results by means of a receiver operating characteristic technique reveals that the predictive accuracy of 94% indicating the excellent performance of the proposed approach for spatial zoning of groundwater Flowing well boundary at Iraqi desert.
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Prediction of groundwater Flowing well zone at An-Najif Province, central Iraq using evidential belief functions model and GIS
Environmental Monitoring and Assessment, 2016Co-Authors: Alaa M. Al-abadi, Biswajeet Pradhan, Shamsuddin ShahidAbstract:The objective of this study is to delineate groundwater Flowing well zone potential in An-Najif Province of Iraq in a data-driven evidential belief function model developed in a geographical information system (GIS) environment. An inventory map of 68 groundwater Flowing Wells was prepared through field survey. Seventy percent or 43 Wells were used for training the evidential belief functions model and the reset 30 % or 19 Wells were used for validation of the model. Seven groundwater conditioning factors mostly derived from RS were used, namely elevation, slope angle, curvature, topographic wetness index, stream power index, lithological units, and distance to the Euphrates River in this study. The relationship between training Flowing well locations and the conditioning factors were investigated using evidential belief functions technique in a GIS environment. The integrated belief values were classified into five categories using natural break classification scheme to predict spatial zoning of groundwater Flowing well, namely very low (0.17–0.34), low (0.34–0.46), moderate (0.46–0.58), high (0.58–0.80), and very high (0.80–0.99). The results show that very low and low zones cover 72 % (19,282 km^2) of the study area mostly clustered in the central part, the moderate zone concentrated in the west part covers 13 % (3481 km^2), and the high and very high zones extended over the northern part cover 15 % (3977 km^2) of the study area. The vast spatial extension of very low and low zones indicates that groundwater Flowing Wells potential in the study area is low. The performance of the evidential belief functions spatial model was validated using the receiver operating characteristic curve. A success rate of 0.95 and a prediction rate of 0.94 were estimated from the area under relative operating characteristics curves, which indicate that the developed model has excellent capability to predict groundwater Flowing well zones. The produced map of groundwater Flowing well zones could be used to identify new Wells and manage groundwater storage in a sustainable manner.
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Spatial mapping of artesian zone at Iraqi southern desert using a GIS-based random forest machine learning model
Modeling Earth Systems and Environment, 2016Co-Authors: Alaa M. Al-abadi, Shamsuddin ShahidAbstract:Random forest (RF) machine learning technique and geographical information system (GIS) have been applied to delineate groundwater Flowing well zones in the southern desert of Iraq. A spatial database consists of target variable, i.e., geographic locations of 93 Flowing Wells and predictor variables, i.e., the factors that control groundwater occurrence was prepared for this purpose. Eleven predictor variables were selected based on data availability, literature review, and field conditions which include elevation, slope, profile curvature, aspect, topographic wetness index, stream power index, distance to Abu Jir fault, distance to Euphrates River, major aquifer group, total hydraulic head, and well depth. The RF model in R package along with ArcGIS 10.2 was used to generate groundwater Flowing well potential index for the study area. The obtained potential indices were classified using natural break classification scheme into five categories namely, very low, low, moderate, high, and very high. The results revealed that high or very high groundwater Flowing well potential zones occupy 15 %, moderate potential zone covers 6 %, and low or very low potential zones cover 79 % of the southern desert of Iraq. The groundwater Flowing well zone map was validated using relative operating characteristic (ROC) curve. The areas under the ROC curve for success and prediction rates were 0.98 and 0.97, respectively, indicating excellent capability of RF model to delineate groundwater potential. It is expected that the method development in this study can be used for rapid but efficient evaluation of groundwater Flowing well potential from limited amount of data.