This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
Groundwater vulnerability maps were constructed for the surface water catchment area of Tanour an... more Groundwater vulnerability maps were constructed for the surface water catchment area of Tanour and Rasoun spring (north-west of Jordan) using the COP and EPIK intrinsic groundwater vulnerability assessment methods. Tanour and Rasoun springs are the main water resources for domestic purposes within the study area. A detailed geological survey was carried out, and data of lithology, karst features, precipitation, vegetation and soil cover, etc. were gathered from various sources for the catchment area in order to determine the required parameters for each method. ArcGIS software was used for map preparation. In the resulting COP vulnerability map, spatial distribution of groundwater vulnerability is as follows: (1) high (37%), (2) moderate (34.8%), (3) low (20.1%), and (4) very low (8.1%). In the EPIK vulnerability map, only two out of four vulnerability classes characterize the catchment area: very high vulnerable areas (38.4%) and moderately vulnerable areas (61.6%). Due to limited soil thickness, the low vulnerability class is absent within the catchment. The high percentage of very high to moderately vulnerable areas displayed by both the COP and EPIK vulnerability assessment methods are reflected by different pollution events in Tanour and Rasoun karst springs especially during the winter season. The high sensitivity of the aquifer to pollution can be explained by different factors such as: thin or absent soil cover, the high development of the epikarst and karst network, and the lithology and confining conditions of the aquifer.
V Vanadium WL Water level WMI Water Management Initiative, USAID funded project WMIS Water Manage... more V Vanadium WL Water level WMI Water Management Initiative, USAID funded project WMIS Water Management Information System, software used by JVA in the Deir Allah Control Center WUA Water User Association WW Wastewater WWTP Wastewater treatment plant YWC Yarmouk Water Company Definitions Allocation Water allocation is the process of distributing water from different water sources to different points of use in a society. Decisions regarding the amount of water that is distributed to which user and for which purpose require an in-depth knowledge of the entity responsible for water allocation, the total amounts that will be available to be distributed, and what the quality at each point of the network will be. Consumption The volume withdrawn that is not returned to the water system (is evaporated, transpired, incorporated into products, plants, or animals) and is no longer available for use. Conventional water resources Surface and groundwater resources Demand Water demand describes the amount of water needed at the customer side. Demand must be predicted to schedule water allocations and to design the necessary transmission and distribution lines, pumping systems, and storage facilities. As many water operations are intermittent, pressure must not exceed critical limits at any point in the network and regular hydraulic network analyses are required to assess network pressure when demand or designs change. Expected average day, maximum day, and peak hour water demand must therefore be determined for any proposed developments. Demand varies over the year depending on climatic influences, socioeconomic influences, the condition of the distribution system, and the conservation practices in use. Domestic demand depends on social criteria such as income or ability to pay, and the number of persons per household connection. Economic status (income) and residential population densities are sometimes used as proxies for these values. Industrial water demand is very dependent on the specific quantity and quality of water needed for each process, and the degree of recycling techniques that are in use. Agricultural water demand depends on the crops being grown, the cropping pattern (how many seasons and which crops are grown where) and the irrigation techniques being used. Domestic demand Is the water consumed through household activities for indoor and outdoor purposes, including toilet flushing, bathing, laundry, dishwashing, cooking, drinking, and the less frequent outdoor use for gardening and car washing, etc. 15 Downward leakage The vertical percolation of water through an aquitard Municipal water Is the water supplied through the water supply network owned and managed by public organization which is WAJ and the water utilities for Jordan. conventional water resources All water resources which are generated for direct use but are not part of conventional water resources (surface and groundwater), i.e. treated wastewater, desalinated water, harvested water. Non-domestic demand Is the water used for industrial, commercial uses (tourism, shops, private offices, schools, universities, hospitals, airports, etc.), public uses (governmental offices, schools, universities, and hospitals) and for irrigation of public spaces occasionally delivered from primary water supply systems. Non-revenue water (NRW) Non-revenue water reflects the difference between the amount of water supplied through the water distribution system and the amount billed to customers. NRW includes physical losses, and apparent losses such as illegal connections and meter inaccuracies. It also includes unbilled authorized consumption. In order to assess NRW, district metered areas (DMAs) with calibrated flow meters are required. Supply requirement The amount of water that has to be produced and transferred to the supply network to meet demand. The supply requirement is based on the average water demand for municipal water adding the physical losses. Unaccountedfor water (UFW) The term UFW is similar to NRW, but excludes authorized unbilled consumption. Unaccounted-for water is the difference between the volume of water delivered in a network and legitimate consumption, both metered and unmetered. Use Water that is withdrawn for a specific purpose, such as for public supply, domestic use, irrigation, thermoelectric-power cooling, or industrial processing Water system A water network structure, which has defined internal supply sources or a known quantity supplied from outside to a clearly defined demand center (often a city, a district or a governorate). Water distributed from (demand requirements), used from (billed consumption) and lost from (physical and administrative losses) a water system can be clearly determined. Water system boundaries and administrative boundaries may be significantly different. A water system can serve a demand center with several localities (villages) with different administrative boundaries within a governorate. A water system may not match with administrative boundaries and one locality may be contained in more than one water system.
Intensive use of land resources in arid and semi-arid regions exert serious pressures on groundwa... more Intensive use of land resources in arid and semi-arid regions exert serious pressures on groundwater resources and jeopardize further socio-economical developments. The Amman-Zarqa Basin (AZB), the most vital basin in Jordan, is facing recent groundwater deterioration due to a very large increase in water demands for domestic, agricultural, and industrial uses. The objectives of this paper were to quantify the degree of contamination in the basin by evaluating the characteristics, distribution and seasonal variations of two pollution indicators (nitrate concentration and salinity) and to determine the impacts of human activities (land use) on groundwater quality. Based upon long-term data (1970-2005) of groundwater samples collected from 538 wells across the AZB, spatial analyses indicated that both indicators have a strong spatial dependence and are anisotropically distributed. Prediction maps of Ordinary Kriging and Indicator Kriging provided detailed indications of the major and minor sources of pollution in the basin. Inefficient wastewater treatment plants, industrial activities and agricultural practices were responsible for 91, 85, and 25% salinization of nearby wells, respectively. Nitrate pollution had reached 73% above threshold (50 mg/L) in some cases. The temporal analyses estimated the salinity buildup rate to be around 8 9 10-2 lS/cm per day, while nitrate buildup rate was estimated to be around 6 9 10-2 mg/L per day. Remote sensing and spatial analyses helped greatly in groundwater quality assessment not only in providing the environmental status of the AZB but also in delineating the potential of contamination risk zones and their correlation to human activities. Furthermore, the paper suggests some environmental protection strategies that should be adopted to protect the vital groundwater resources of the basin from further deterioration.
ABSTRACT This guideline focuses on development of a “general reference monitoring programme” for ... more ABSTRACT This guideline focuses on development of a “general reference monitoring programme” for the early stage of groundwater reconnaissance, groundwater development and groundwater management. The objectives of the monitoring programme are to supply data for characterisation of the regional groundwater systems, identification of trends in time and prediction of the regional impacts of groundwater abstraction. Technical as well as institutional and budgetary aspects will be discussed.
This report presents the results of a surface karst feature survey, conducted by the Technical Co... more This report presents the results of a surface karst feature survey, conducted by the Technical Cooperation (TC) Project Protection of Jeita Spring (implemented by BGR and CDR). This survey was needed for the preparation of groundwater vulnerability to be prepared by the University of Goettingen for the project. Together with the hydrogeological investigations of the project, the groundwater vulnerability formed the basis for the delineation of groundwater protection zones for the Jeita spring and other important springs and wells in the Jeita catchment. A large share of geological units at outcrop consist of limestones (75%). Limestone of Jurassic age represents 30 %, while limestone of Cretaceous age makes up 45 %. Due to the specific conditions (lithology, structural development, exposure, palaeoclimate) prevailing in the Jeita catchment during the geological history, all limestone units are intensively karstified. Only 25 % of the outcrop area in the Jeita catchment is composed of non-karstic units. The intensive karstification created pathways for infiltration of water into the aquifer system and allows a relatively fast movement of groundwater as was observed through numerous tracer tests. Based on spring discharge measurements in the catchment groundwater recharge rates reach around 80 % in the Upper Cretaceous limestone and around 60 % in the Jurassic limestone. Evidence for extensive Quaternary glaciations in the Mount Lebanon mountain range has been found by the project. During these glaciations karstification processes were probably even more extensive than today. Fracture porosity in the lower part of the Jurassic aquifer seems to be low because fractures are mostly filled. Here groundwater flow mainly follows large conduits. Partly an extensive secondary dolomitization of the Kesrouane Formation (J4) of the Jurassic is noticed. Calcium magnesium carbonate (dolomite) is much less soluble than calcium carbonate (limestone). Therefore karstification in dolomite is significantly less compared to limestone. It is assumed that dolomitization is related to intrusions of basalt and related hydrothermal waters along fractures. Understanding the development of the karst system is paramount for the interpretation of the hydrogeology in the Jeita catchment. Groundwater flow is governed to a large extent by the geological structure. The study of the palaeoclimate, geological structure and tectonic development is key to an understanding of karst development and groundwater flow.
Groundwater quality has been deteriorating in many parts of Jordan in recent years due to rapid u... more Groundwater quality has been deteriorating in many parts of Jordan in recent years due to rapid urban development, expansion of agriculture, and industrialization. The country, however, can ill afford a situation in which precious water resources are lost due to pollution. Land use planning is often done without taking aspects of groundwater protection sufficiently into account. Discussions with the relevant authorities clearly showed the need for planning documents that take aspects of groundwater contamination into consideration. For this purpose, a program of mapping the ‘intrinsic’ groundwater vulnerability in Jordan has been initiated within the framework of a Technical Cooperation Project between the Water Authority of Jordan (WAJ) and the Federal Institute of Geosciences and Natural Resources (BGR) in Germany. The methodology is based on a system developed by State Geological Surveys in Germany. In Jordan, this methodology has been applied to study groundwater vulnerability a...
Water scarcity drives governments in arid and semi-arid regions to promote strategies for improvi... more Water scarcity drives governments in arid and semi-arid regions to promote strategies for improving water use efficiency. Water-related research generally also plays an important role in the same countries and for the same reason. However, it remains unclear how to link the implementation of new government strategies and water-related research. This article’s principal objective is to present a novel approach that defines water-related research gaps from the point of view of a government strategy. The proposed methodology is based on an extensive literature review, followed by a systematic evaluation of the topics covered both in grey and peer-reviewed literature. Finally, we assess if and how the different literature sources contribute to the goals of the water strategy. The methodology was tested by investigating the impact of the water strategy of Jordan’s government (2008–2022) on the research conducted in the Azraq Basin, considering 99 grey and peer-reviewed documents. The res...
Artificial tracer experiments were conducted in the mature karst system of Jeita (Lebanon) under ... more Artificial tracer experiments were conducted in the mature karst system of Jeita (Lebanon) under various flow conditions using surface and subsurface tracer injection points, to determine the variation of transport parameters (attenuation of peak concentration, velocity, transit times, dispersivity, and proportion of immobile and mobile regions) along fast and slow flow pathways. Tracer breakthrough curves (TBCs) observed at the karst spring were interpreted using a two-region nonequilibrium approach (2RNEM) to account for the skewness in the TBCs' long tailings. The conduit test results revealed a discharge threshold in the system dynamics, beyond which the transport parameters vary significantly. The polynomial relationship between transport velocity and discharge can be related to the variation of the conduit's crosssectional area. Longitudinal dispersivity in the conduit system is not a constant value (α = 7-10 m) and decreases linearly with increasing flow rate because of dilution effects. Additionally, the proportion of immobile regions (arising from conduit irregularities) increases with decreasing water level in the conduit system. From tracer tests with injection at the surface, longitudinal dispersivity values are found to be large (8-27 m). The tailing observed in some TBCs is generated in the unsaturated zone before the tracer actually arrives at the major subsurface conduit draining the system. This work allows the estimation and prediction of the key transport parameters in karst aquifers. It shows that these parameters vary with time and flow dynamics, and they reflect the geometry of the flow pathway and the origin of infiltrating (potentially contaminated) recharge.
The use of reclaimed water and its impact on groundwater quality in the middle and southern parts... more The use of reclaimed water and its impact on groundwater quality in the middle and southern parts of the Jordan Valley are investigated. The chemical analyses indicate that nitrate and bacteriological pollution is widespread, and thus, seriously affects groundwater use. During the study, 365 water samples were collected from wells and springs to determine the water chemistry and the extent of nitrate pollution. Three hydrochemical facies are identifed, i. e., (Ca-(Mg)-Na-HCO 3), (Ca-Na-SO 4-Cl) and (Ca-Na-Cl). The change of facies is accompanied by a gradual increase in the groundwater total dissolved solids (TDS), which is mainly controlled by evaporates and carbonates dissolution in the aquifer matrix. Water analyses indicate that the shallow aquifer in the study area is affected by non-point pollution sources, primarily from natural (manure) and chemical nitrogen (N)-fertilizers and treated wastewater used for agriculture. The concentration of nitrate in the groundwater ranges from 10 to 355 mg/L. Considerable seasonal fluctuations in groundwater quality are observed as a consequence of agricultural practices and other factors such as annual rainfall distribution and the Zarqa River flow. The noticeable levels of total coliform and Escherichia coli in the northern part of the study area may be attributed to contamination from the urban areas, intensive livestock production, and illegal dumping of sewage. Heavy metal concentrations in all samples were found to be significantly lower than the permissible limits for drinking water standards.
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
Groundwater vulnerability maps were constructed for the surface water catchment area of Tanour an... more Groundwater vulnerability maps were constructed for the surface water catchment area of Tanour and Rasoun spring (north-west of Jordan) using the COP and EPIK intrinsic groundwater vulnerability assessment methods. Tanour and Rasoun springs are the main water resources for domestic purposes within the study area. A detailed geological survey was carried out, and data of lithology, karst features, precipitation, vegetation and soil cover, etc. were gathered from various sources for the catchment area in order to determine the required parameters for each method. ArcGIS software was used for map preparation. In the resulting COP vulnerability map, spatial distribution of groundwater vulnerability is as follows: (1) high (37%), (2) moderate (34.8%), (3) low (20.1%), and (4) very low (8.1%). In the EPIK vulnerability map, only two out of four vulnerability classes characterize the catchment area: very high vulnerable areas (38.4%) and moderately vulnerable areas (61.6%). Due to limited soil thickness, the low vulnerability class is absent within the catchment. The high percentage of very high to moderately vulnerable areas displayed by both the COP and EPIK vulnerability assessment methods are reflected by different pollution events in Tanour and Rasoun karst springs especially during the winter season. The high sensitivity of the aquifer to pollution can be explained by different factors such as: thin or absent soil cover, the high development of the epikarst and karst network, and the lithology and confining conditions of the aquifer.
V Vanadium WL Water level WMI Water Management Initiative, USAID funded project WMIS Water Manage... more V Vanadium WL Water level WMI Water Management Initiative, USAID funded project WMIS Water Management Information System, software used by JVA in the Deir Allah Control Center WUA Water User Association WW Wastewater WWTP Wastewater treatment plant YWC Yarmouk Water Company Definitions Allocation Water allocation is the process of distributing water from different water sources to different points of use in a society. Decisions regarding the amount of water that is distributed to which user and for which purpose require an in-depth knowledge of the entity responsible for water allocation, the total amounts that will be available to be distributed, and what the quality at each point of the network will be. Consumption The volume withdrawn that is not returned to the water system (is evaporated, transpired, incorporated into products, plants, or animals) and is no longer available for use. Conventional water resources Surface and groundwater resources Demand Water demand describes the amount of water needed at the customer side. Demand must be predicted to schedule water allocations and to design the necessary transmission and distribution lines, pumping systems, and storage facilities. As many water operations are intermittent, pressure must not exceed critical limits at any point in the network and regular hydraulic network analyses are required to assess network pressure when demand or designs change. Expected average day, maximum day, and peak hour water demand must therefore be determined for any proposed developments. Demand varies over the year depending on climatic influences, socioeconomic influences, the condition of the distribution system, and the conservation practices in use. Domestic demand depends on social criteria such as income or ability to pay, and the number of persons per household connection. Economic status (income) and residential population densities are sometimes used as proxies for these values. Industrial water demand is very dependent on the specific quantity and quality of water needed for each process, and the degree of recycling techniques that are in use. Agricultural water demand depends on the crops being grown, the cropping pattern (how many seasons and which crops are grown where) and the irrigation techniques being used. Domestic demand Is the water consumed through household activities for indoor and outdoor purposes, including toilet flushing, bathing, laundry, dishwashing, cooking, drinking, and the less frequent outdoor use for gardening and car washing, etc. 15 Downward leakage The vertical percolation of water through an aquitard Municipal water Is the water supplied through the water supply network owned and managed by public organization which is WAJ and the water utilities for Jordan. conventional water resources All water resources which are generated for direct use but are not part of conventional water resources (surface and groundwater), i.e. treated wastewater, desalinated water, harvested water. Non-domestic demand Is the water used for industrial, commercial uses (tourism, shops, private offices, schools, universities, hospitals, airports, etc.), public uses (governmental offices, schools, universities, and hospitals) and for irrigation of public spaces occasionally delivered from primary water supply systems. Non-revenue water (NRW) Non-revenue water reflects the difference between the amount of water supplied through the water distribution system and the amount billed to customers. NRW includes physical losses, and apparent losses such as illegal connections and meter inaccuracies. It also includes unbilled authorized consumption. In order to assess NRW, district metered areas (DMAs) with calibrated flow meters are required. Supply requirement The amount of water that has to be produced and transferred to the supply network to meet demand. The supply requirement is based on the average water demand for municipal water adding the physical losses. Unaccountedfor water (UFW) The term UFW is similar to NRW, but excludes authorized unbilled consumption. Unaccounted-for water is the difference between the volume of water delivered in a network and legitimate consumption, both metered and unmetered. Use Water that is withdrawn for a specific purpose, such as for public supply, domestic use, irrigation, thermoelectric-power cooling, or industrial processing Water system A water network structure, which has defined internal supply sources or a known quantity supplied from outside to a clearly defined demand center (often a city, a district or a governorate). Water distributed from (demand requirements), used from (billed consumption) and lost from (physical and administrative losses) a water system can be clearly determined. Water system boundaries and administrative boundaries may be significantly different. A water system can serve a demand center with several localities (villages) with different administrative boundaries within a governorate. A water system may not match with administrative boundaries and one locality may be contained in more than one water system.
Intensive use of land resources in arid and semi-arid regions exert serious pressures on groundwa... more Intensive use of land resources in arid and semi-arid regions exert serious pressures on groundwater resources and jeopardize further socio-economical developments. The Amman-Zarqa Basin (AZB), the most vital basin in Jordan, is facing recent groundwater deterioration due to a very large increase in water demands for domestic, agricultural, and industrial uses. The objectives of this paper were to quantify the degree of contamination in the basin by evaluating the characteristics, distribution and seasonal variations of two pollution indicators (nitrate concentration and salinity) and to determine the impacts of human activities (land use) on groundwater quality. Based upon long-term data (1970-2005) of groundwater samples collected from 538 wells across the AZB, spatial analyses indicated that both indicators have a strong spatial dependence and are anisotropically distributed. Prediction maps of Ordinary Kriging and Indicator Kriging provided detailed indications of the major and minor sources of pollution in the basin. Inefficient wastewater treatment plants, industrial activities and agricultural practices were responsible for 91, 85, and 25% salinization of nearby wells, respectively. Nitrate pollution had reached 73% above threshold (50 mg/L) in some cases. The temporal analyses estimated the salinity buildup rate to be around 8 9 10-2 lS/cm per day, while nitrate buildup rate was estimated to be around 6 9 10-2 mg/L per day. Remote sensing and spatial analyses helped greatly in groundwater quality assessment not only in providing the environmental status of the AZB but also in delineating the potential of contamination risk zones and their correlation to human activities. Furthermore, the paper suggests some environmental protection strategies that should be adopted to protect the vital groundwater resources of the basin from further deterioration.
ABSTRACT This guideline focuses on development of a “general reference monitoring programme” for ... more ABSTRACT This guideline focuses on development of a “general reference monitoring programme” for the early stage of groundwater reconnaissance, groundwater development and groundwater management. The objectives of the monitoring programme are to supply data for characterisation of the regional groundwater systems, identification of trends in time and prediction of the regional impacts of groundwater abstraction. Technical as well as institutional and budgetary aspects will be discussed.
This report presents the results of a surface karst feature survey, conducted by the Technical Co... more This report presents the results of a surface karst feature survey, conducted by the Technical Cooperation (TC) Project Protection of Jeita Spring (implemented by BGR and CDR). This survey was needed for the preparation of groundwater vulnerability to be prepared by the University of Goettingen for the project. Together with the hydrogeological investigations of the project, the groundwater vulnerability formed the basis for the delineation of groundwater protection zones for the Jeita spring and other important springs and wells in the Jeita catchment. A large share of geological units at outcrop consist of limestones (75%). Limestone of Jurassic age represents 30 %, while limestone of Cretaceous age makes up 45 %. Due to the specific conditions (lithology, structural development, exposure, palaeoclimate) prevailing in the Jeita catchment during the geological history, all limestone units are intensively karstified. Only 25 % of the outcrop area in the Jeita catchment is composed of non-karstic units. The intensive karstification created pathways for infiltration of water into the aquifer system and allows a relatively fast movement of groundwater as was observed through numerous tracer tests. Based on spring discharge measurements in the catchment groundwater recharge rates reach around 80 % in the Upper Cretaceous limestone and around 60 % in the Jurassic limestone. Evidence for extensive Quaternary glaciations in the Mount Lebanon mountain range has been found by the project. During these glaciations karstification processes were probably even more extensive than today. Fracture porosity in the lower part of the Jurassic aquifer seems to be low because fractures are mostly filled. Here groundwater flow mainly follows large conduits. Partly an extensive secondary dolomitization of the Kesrouane Formation (J4) of the Jurassic is noticed. Calcium magnesium carbonate (dolomite) is much less soluble than calcium carbonate (limestone). Therefore karstification in dolomite is significantly less compared to limestone. It is assumed that dolomitization is related to intrusions of basalt and related hydrothermal waters along fractures. Understanding the development of the karst system is paramount for the interpretation of the hydrogeology in the Jeita catchment. Groundwater flow is governed to a large extent by the geological structure. The study of the palaeoclimate, geological structure and tectonic development is key to an understanding of karst development and groundwater flow.
Groundwater quality has been deteriorating in many parts of Jordan in recent years due to rapid u... more Groundwater quality has been deteriorating in many parts of Jordan in recent years due to rapid urban development, expansion of agriculture, and industrialization. The country, however, can ill afford a situation in which precious water resources are lost due to pollution. Land use planning is often done without taking aspects of groundwater protection sufficiently into account. Discussions with the relevant authorities clearly showed the need for planning documents that take aspects of groundwater contamination into consideration. For this purpose, a program of mapping the ‘intrinsic’ groundwater vulnerability in Jordan has been initiated within the framework of a Technical Cooperation Project between the Water Authority of Jordan (WAJ) and the Federal Institute of Geosciences and Natural Resources (BGR) in Germany. The methodology is based on a system developed by State Geological Surveys in Germany. In Jordan, this methodology has been applied to study groundwater vulnerability a...
Water scarcity drives governments in arid and semi-arid regions to promote strategies for improvi... more Water scarcity drives governments in arid and semi-arid regions to promote strategies for improving water use efficiency. Water-related research generally also plays an important role in the same countries and for the same reason. However, it remains unclear how to link the implementation of new government strategies and water-related research. This article’s principal objective is to present a novel approach that defines water-related research gaps from the point of view of a government strategy. The proposed methodology is based on an extensive literature review, followed by a systematic evaluation of the topics covered both in grey and peer-reviewed literature. Finally, we assess if and how the different literature sources contribute to the goals of the water strategy. The methodology was tested by investigating the impact of the water strategy of Jordan’s government (2008–2022) on the research conducted in the Azraq Basin, considering 99 grey and peer-reviewed documents. The res...
Artificial tracer experiments were conducted in the mature karst system of Jeita (Lebanon) under ... more Artificial tracer experiments were conducted in the mature karst system of Jeita (Lebanon) under various flow conditions using surface and subsurface tracer injection points, to determine the variation of transport parameters (attenuation of peak concentration, velocity, transit times, dispersivity, and proportion of immobile and mobile regions) along fast and slow flow pathways. Tracer breakthrough curves (TBCs) observed at the karst spring were interpreted using a two-region nonequilibrium approach (2RNEM) to account for the skewness in the TBCs' long tailings. The conduit test results revealed a discharge threshold in the system dynamics, beyond which the transport parameters vary significantly. The polynomial relationship between transport velocity and discharge can be related to the variation of the conduit's crosssectional area. Longitudinal dispersivity in the conduit system is not a constant value (α = 7-10 m) and decreases linearly with increasing flow rate because of dilution effects. Additionally, the proportion of immobile regions (arising from conduit irregularities) increases with decreasing water level in the conduit system. From tracer tests with injection at the surface, longitudinal dispersivity values are found to be large (8-27 m). The tailing observed in some TBCs is generated in the unsaturated zone before the tracer actually arrives at the major subsurface conduit draining the system. This work allows the estimation and prediction of the key transport parameters in karst aquifers. It shows that these parameters vary with time and flow dynamics, and they reflect the geometry of the flow pathway and the origin of infiltrating (potentially contaminated) recharge.
The use of reclaimed water and its impact on groundwater quality in the middle and southern parts... more The use of reclaimed water and its impact on groundwater quality in the middle and southern parts of the Jordan Valley are investigated. The chemical analyses indicate that nitrate and bacteriological pollution is widespread, and thus, seriously affects groundwater use. During the study, 365 water samples were collected from wells and springs to determine the water chemistry and the extent of nitrate pollution. Three hydrochemical facies are identifed, i. e., (Ca-(Mg)-Na-HCO 3), (Ca-Na-SO 4-Cl) and (Ca-Na-Cl). The change of facies is accompanied by a gradual increase in the groundwater total dissolved solids (TDS), which is mainly controlled by evaporates and carbonates dissolution in the aquifer matrix. Water analyses indicate that the shallow aquifer in the study area is affected by non-point pollution sources, primarily from natural (manure) and chemical nitrogen (N)-fertilizers and treated wastewater used for agriculture. The concentration of nitrate in the groundwater ranges from 10 to 355 mg/L. Considerable seasonal fluctuations in groundwater quality are observed as a consequence of agricultural practices and other factors such as annual rainfall distribution and the Zarqa River flow. The noticeable levels of total coliform and Escherichia coli in the northern part of the study area may be attributed to contamination from the urban areas, intensive livestock production, and illegal dumping of sewage. Heavy metal concentrations in all samples were found to be significantly lower than the permissible limits for drinking water standards.
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