Groundwater Research Papers - Academia.edu (original) (raw)

ph: (865) 576-8401 fax: (865) 576-5728 email: reports@adonis.osti.gov Available to the public from the National Technical Information Service, U.S. Department of Commerce, 5285 Port Royal Rd., Springfield, VA 22161 ph: (800) 553-6847 fax:... more

ph: (865) 576-8401 fax: (865) 576-5728 email: reports@adonis.osti.gov Available to the public from the National Technical Information Service, U.S. Department of Commerce, 5285 Port Royal Rd., Springfield, VA 22161 ph: (800) 553-6847 fax: (703) 605-6900 email: orders@ntis.fedworld.gov online ordering: http://www.ntis.gov/ordering.htm

1] Hyporheic flow results from the interaction between streamflow and channel morphology and is an important component of stream ecosystems because it enhances water and solute exchange between the river and its bed. Hyporheic flow in... more

1] Hyporheic flow results from the interaction between streamflow and channel morphology and is an important component of stream ecosystems because it enhances water and solute exchange between the river and its bed. Hyporheic flow in pool-riffle channels is particularly complex because of three-dimensional topography that spans a range of partially to fully submerged conditions, inducing both static and dynamic head variations. Hence, these channels exhibit transitional conditions of streambed pressure and hyporheic flow compared to previous studies of fully submerged, two-dimensional bed forms. Here, we conduct a series of three-dimensional simulations to investigate the effects of bed topography, depth of alluvium, and stream discharge on hyporheic flow in pool-riffle reaches with variable bed form submergence, and we propose three empirical formulae to predict the mean depth of hyporheic exchange and characteristic values of the residence time distribution (mean and standard deviation). Hyporheic exchange is predicted with a three-dimensional pumping model, and hyporheic flow is modeled as a Darcy flow. We find that the hyporheic residence time is well approximated by a lognormal distribution for both partially and entirely submerged pool-riffle topography, with the parameters of the distribution defined by the mean and variance of the log-transformed residence time. Depth of alluvium has a substantial effect on hyporheic flow when alluvial depth is less than a third of the bed form wavelength for the conditions examined.

Detailed characterisation and 3D-modelling of the shallow subsurface was carried out for the construction of a Radial Collector Well (RCW) at the drinking water pumping station of Brabant Water at Macharen (near 's Hertogenbosch, province... more

Detailed characterisation and 3D-modelling of the shallow subsurface was carried out for the construction of a Radial Collector Well (RCW) at the drinking water pumping station of Brabant Water at Macharen (near 's Hertogenbosch, province of Noord-Brabant, southern Netherlands). The objective was to assess the lithological and hydraulic properties of the uppermost 30 m of the subsoil in order to find the optimal depth and orientation of the 4 horizontal collector arms of the RCW.

This study presents the results of a multidisciplinary approach, using hydrogeochemical, isotopic and ecotoxicological analyses, performed to assess the nature and suitability for use of Paranhos and Salgueiros spring waters (Porto city,... more

This study presents the results of a multidisciplinary approach, using hydrogeochemical, isotopic and ecotoxicological analyses, performed to assess the nature and suitability for use of Paranhos and Salgueiros spring waters (Porto city, NW Portugal). Based on the surface activities located along the course of the springs, 23 water samples were collected. All the samples were analysed for major element concentrations. The isotopic techniques employed included d 2 H, d 18 O and 3 H. Standard acute bioassays with Daphnia magna were also performed. The hydrogeochemical analyses showed a nitrate and sulphateenriched composition for these groundwaters, resulting mainly from urban drainage and sewer leakage. In the ecotoxicological analyses, no significant mortality was observed in any of the tests performed. The results obtained in this study suggest that Porto urban groundwater could be suitable for irrigation uses.

Perfluorinated substances are listed among emerging contaminants because they are globally distributed, environmentally persistent, bioaccumulative and potentially harmful. In a three-year monitoring campaign (2010-2013) we investigated... more

Perfluorinated substances are listed among emerging contaminants because they are globally distributed, environmentally persistent, bioaccumulative and potentially harmful. In a three-year monitoring campaign (2010-2013) we investigated the occurrence, sources and fate of nine perfluoroalkylcarboxylic acids and three perfluoroalkylsulfonic acids, in the most industrialized region of Italy. Composite samples were collected in influents and effluents of wastewater treatment plants (WWTPs), in the main rivers flowing through the basin, and in raw groundwater and finished drinking water. Samples were analyzed by liquid chromatography tandem mass spectrometry. Perfluorinated substances were not removed in WWTPs and those receiving industrial wastes discharged up to 50 times the loads of WWTPs receiving municipal wastes. The mass balance of the emissions in the River Lambro basin showed continuously increasing contamination from north to south and differences in the composition of homologues in the west and east sides of the basin. Ground and drinking water were contaminated in industrial areas, but these substances were removed well in Milan. Contamination from industrial sources was prevalent over urban sources, contributing to 90% of the loads measured at the closure of the basin. The River Lambro was confirmed as one of the main sources of contamination in the Po River.

Before the emergence of microbiology in the 1860s, the relationship between health and water was understood to hinge mostly on its manifold mineral qualities; medical treatments often involved bathing in particular waters to take... more

Before the emergence of microbiology in the 1860s, the relationship between health and water was understood to hinge mostly on its manifold mineral qualities; medical treatments often involved bathing in particular waters to take advantage of their curative powers. With the help of microscopes, those waters came to be seen as home to dangerous microbes and a cause, as much as a cure, of disease. But while biology placed water management on a new footing, ideas from chemistry about the diverse positive medical effects of mineral waters continued to justify the use of those heterogeneous sources for bathing in pools and spas. In this article, I trace this slow, incomplete transition from chemical to biological understandings of waters and health in Mexico City in the late 19th and early 20th centuries. Contradictory hydrosocial processes took shape as scientists, businesspeople and politicians sought to deliver biologically pure, potable public water to individual bathrooms and to, at the same time, promote the healing properties of social bathing in chemically heterogeneous waters.

Consumption of inorganic arsenic in drinking water at high levels has been associated with chronic diseases. Risk is less clear at lower levels of arsenic, in part due to difficulties in estimating exposure. Herein we characterize spatial... more

Consumption of inorganic arsenic in drinking water at high levels has been associated with chronic diseases. Risk is less clear at lower levels of arsenic, in part due to difficulties in estimating exposure. Herein we characterize spatial and temporal variability of arsenic concentrations and develop models for predicting aquifer arsenic concentrations in the San Luis Valley, Colorado, an area of moderately elevated arsenic in groundwater. This study included historical water samples with total arsenic concentrations from 595 unique well locations. A longitudinal analysis established temporal stability in arsenic levels in individual wells. The mean arsenic levels for a random sample of 535 wells were incorporated into five kriging models to predict groundwater arsenic concentrations at any point in time. A separate validation dataset (n = 60 wells) was used to identify the model with strongest predictability. Findings indicate that arsenic concentrations are temporally stable (r = 0.88; 95 % CI 0.83-0.92 for samples collected from the same well 15-25 years apart) and the spatial model created using ordinary kriging best predicted arsenic concentrations (q = 0.72 between predicted and observed validation data). These findings illustrate the value of geostatistical modeling of arsenic and suggest the San Luis Valley is a good region for conducting epidemiologic studies of groundwater metals because of the ability to accurately predict variation in groundwater arsenic concentrations.

Artificial Neural Networks (ANNs) have been found to be a robust tool to model many non-linear hydrological processes. The present study aims at evaluating the performance of ANN in simulating and predicting ground water levels in the... more

Artificial Neural Networks (ANNs) have been found to be a robust tool to model many non-linear hydrological processes. The present study aims at evaluating the performance of ANN in simulating and predicting ground water levels in the uplands of a tropical coastal riparian wetland. The study involves comparison of two network architectures, Feed Forward Neural Network (FFNN) and Recurrent Neural Network (RNN) trained under five algorithms namely Levenberg Marquardt algorithm, Resilient Back propagation algorithm, BFGS Quasi Newton algorithm, Scaled Conjugate Gradient algorithm, and Fletcher Reeves Conjugate Gradient algorithm by simulating the water levels in a well in the study area. The study is analyzed in two cases-one with four inputs to the networks and two with eight inputs to the networks. The two networks-five algorithms in both the cases are compared to determine the best performing combination that could simulate and predict the process satisfactorily. Ad Hoc (Trial and Error) method is followed in optimizing network structure in all cases. On the whole, it is noticed from the results that the Artificial Neural Networks have simulated and predicted the water levels in the well with fair accuracy. This is evident from low values of Normalized Root Mean Square Error and Relative Root Mean Square Error and high values of Nash-Sutcliffe Efficiency Index and Correlation Coefficient (which are taken as the performance measures to calibrate the networks) calculated after the analysis. On comparison of ground water levels predicted with those at the observation well, FFNN trained with Fletcher Reeves Conjugate Gradient algorithm taken four inputs has outperformed all other combinations.

A number of serious studies have been conducted to decipher relationships between geological environment, potable/drinking water, and diseases as they were considered to have triggered suffering due to diseases among people. Chronic... more

A number of serious studies have been conducted to decipher relationships between geological environment, potable/drinking water, and diseases as they were considered to have triggered suffering due to diseases among people. Chronic anemia can be caused by prolonged exposure to drinking water contaminated with cadmium (Cd). Under such circumstances, accumulation of Cd is manifested in the kidney, resulting in cancer and cardiovascular diseases. The aim of this study is to present the impact of Cd-contaminated drinking water on human health among the residents of villages in Winder. Collection of about 48 groundwater samples at an average distance of 1 to 2 km between the sampling sites has enabled a sufficient geological representation of distribution of minerals and elements in the samples. Concentration and comparison of Cd in the study area sample sites reveal highest values (24.2-30.0 ppb) in the northeastern and southeastern sectors, covering parts of all three geological areas...

A rapid growth of urbanization and industrialization is observed in Rangpur city after becoming a new administrative division of Bangladesh. As a result, the demand for consumptive water use has prominently increased here. The main source... more

A rapid growth of urbanization and industrialization is observed in Rangpur city after becoming a new administrative division of Bangladesh. As a result, the demand for consumptive water use has prominently increased here. The main source of drinking water for most of the working-class people and slum-dwellers are public tube-wells that are installed at the masjid, school, college, marketplace, bus stand, and roadside. Though the water quality is a major concern, there is lack of monitoring of drinking water quality. Hence, this study aims to assess the water quality of the public tube-wells and find out its suitability as drinking water according to the Bangladesh ECR1997 and WHO guidelines. Fifteen water samples were collected from public tube-wells of Rangpur City and some important water quality parameters were tested. After testing, the values of different parameters were statistically analyzed to determine the maximum, minimum, mean, median, and standard deviation. The spatial distribution was illustrated by GIS mapping. The average value of pH 6.75, Total Dissolved Solids 186.2 mg/L, Conductivity 401.98 µS/cm, Dissolved Oxygen 4.34 mg/L, Total Hardness 117.67 mg/L, Alkalinity 107.33 mg/L, Total Iron 1.247 mg/L, Copper 0.067 mg/L, Phosphate 0.35 mg/L, and Chloride 31.56 mg/L. Most of the parameters have been found within the permissible limit but total iron of few samples exceeds the limit. The study reveals that the public tube-well water is safe for consumption. Finally, the geo-spatial map is generated that depicts the distribution of each water quality parameter in Rangpur City.

The Central Asian lowlands are characterized by an arid and continental climate. At the same time, the large streams and rivers have been providing water for the development of flourishing oases and extensive irrigated farming areas.... more

The Central Asian lowlands are characterized by an arid and continental climate. At the same time, the large streams and rivers have been providing water for the development of flourishing oases and extensive irrigated farming areas. Bukhara is one of those oases. The population of 1.7 mln. and especially the agricultural sector (with an irrigated area of 275,000 ha) use a considerable amount of water. But as the flat topography does not provide sufficient natural drainage, water logging and raising groundwater tables have become serious problems for the agricultural productivity. The combination of the high salinity of the irrigation water and the generous application of fertilizers leads to a widespread soil salinization. Excessive leaching is supposed to reduce the top soil salinity, but as the drainage system is only covering a small portion of the irrigated areas and is in need of maintenance, this process only contributes to the ongoing salinization and the reduction of soil f...

A molecular approach, based on the detection of ribulose-1,5-bisphosphate carboxylase/oxygenase (RubisCO) large subunit genes, was applied to investigate the distribution and diversity of autotrophic bacteria in groundwater systems. DNA... more

A molecular approach, based on the detection of ribulose-1,5-bisphosphate carboxylase/oxygenase (RubisCO) large subunit genes, was applied to investigate the distribution and diversity of autotrophic bacteria in groundwater systems. DNA extracts from 48 sampling stations, including a variety of pristine and polluted, shallow and deep-subsurface groundwater samples obtained from Germany and Austria, served as a template for the PCR amplification of form I (cbbL) and form II (cbbM) large subunit RubisCO genes. The majority of the samples (480%) contained two different forms of RubisCO. In 17 samples, all three forms of RubisCO were identified. PCR products from four selected groundwater habitats containing all three forms of RubisCO were used to construct clone libraries. Based on restriction fragment length polymorphism (RFLP) analysis, 109 RubisCO-clone-inserts were subjected to sequencing and phylogenetic analysis. With the exception of a form IA RubisCO sequence cluster obtained from deep subsurface samples, which was identical to the RubisCO genes described for Ralstonia metallidurans CH34, most sequences were distantly related to a variety of RubisCO species in chemolithoautotrophic Proteobacteria. Several sequences occurred in isolated lineages. These findings suggest that autotrophic bacteria with the capability to assimilate CO 2 via the Calvin Cycle pathway are widespread inhabitants of groundwater systems.

Performance assessment Variability Uncertainty Regression analysis Experimental design a b s t r a c t Inflow and Infiltration (I/I ) into sewer systems is generally unwanted, because, among other things, it decreases the performance of... more

Performance assessment Variability Uncertainty Regression analysis Experimental design a b s t r a c t Inflow and Infiltration (I/I ) into sewer systems is generally unwanted, because, among other things, it decreases the performance of wastewater treatment plants and increases combined sewage overflows. As sewer rehabilitation to reduce I/I is very expensive, water managers not only need methods to accurately measure I/I, but also they need sound approaches to assess the actual performance of implemented rehabilitation measures.

The aim of this paper is to present an assessment of nitrates fluxes in the groundwater in Timis County using some direct measurements, as well as their spatial distribution. The presence of the high nitrogen concentrations in soils is a... more

The aim of this paper is to present an assessment of nitrates fluxes in the groundwater in Timis County using some direct measurements, as well as their spatial distribution. The presence of the high nitrogen concentrations in soils is a high potential risk for the groundwater and, implicitly, for human and animal health, the groundwater being the main source of the drinking water in many rural areas. One of the main risk factor for nitrates pollution is the agricultural activity, through the application of the mineral and organic fertilizers doses. As EU country, Romania has to report to international committees the state of nitrate pollution, in the respect of Nitrate Directive, in order to promote a sustainable agriculture based on suitable agricultural practices application for environmental protection. Several information systems, assessing and monitoring the potential vulnerable zones to nitrates, using pre-established indicators, have been developed. In order to assess the in...

The accuracy of the Content should not be relied upon and should be independently verified with primary sources of information. Taylor and Francis shall not be liable for any losses, actions, claims, proceedings, demands, costs, expenses,... more

The accuracy of the Content should not be relied upon and should be independently verified with primary sources of information. Taylor and Francis shall not be liable for any losses, actions, claims, proceedings, demands, costs, expenses, damages, and other liabilities whatsoever or howsoever caused arising directly or indirectly in connection with, in relation to or arising out of the use of the Content. This article may be used for research, teaching, and private study purposes. Any substantial or systematic reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in any form to anyone is expressly forbidden.

1] We examined how landscape hydrogeologic characteristics influence groundwater nitrate removal by eight stream riparian sites on glacial till and outwash landscapes in southern Ontario, Canada. During high water table periods in... more

1] We examined how landscape hydrogeologic characteristics influence groundwater nitrate removal by eight stream riparian sites on glacial till and outwash landscapes in southern Ontario, Canada. During high water table periods in 2000-2002, mean NO 3 À -N input concentrations from adjacent cropland to the riparian sites ranged from 0.15 to 44.7 mg L À1 . Seven of the eight sites had a mean nitrate removal efficiency of >90%. This removal occurred within the first 15 m of the riparian zone at three sites with loamy sand and sandy loam soils overlying a shallow confining layer at 1-2 m. However, at four of five sites with more conductive sand and cobble sediments the width required for 90% nitrate removal varied from >25 m to a maximum of 176 m at a site with a confining layer at 6 m. Sites linked to an extensive thick (>6 m) upland aquifer with a slope gradient of >15% at the riparian perimeter had high nitrate inputs throughout the year and were large nitrate sinks. Sites with gentle topography (<4-5%) and <2 m of permeable sediments were minor nitrate sinks because of small nitrate inputs that were limited to the late autumn-spring period. A conceptual model linking landscape hydrogeologic characteristics to riparian zone nitrate removal capacity is developed to understand and predict the effectiveness of riparian buffers at the landscape scale.

The distribution of groundwater beneath Masaya Volcano, in Nicaragua, and its surrounding caldera was characterized using the transient electromagnetic method (TEM). Multiple soundings were conducted at 30 sites. Models of the TEM data... more

The distribution of groundwater beneath Masaya Volcano, in Nicaragua, and its surrounding caldera was characterized using the transient electromagnetic method (TEM). Multiple soundings were conducted at 30 sites. Models of the TEM data consistently indicate a resistive layer that is underlain by one or more conductive layers. These two layers represent the unsaturated and saturated zones, respectively, with the boundary between them indicating the water-table elevation. A map of the TEM data shows that the water table in the caldera is a subdued replica of the topography, with higher elevations beneath the edifice in the southcentral caldera and lower elevations in the eastern caldera, coinciding with the elevation of Laguna de Masaya. These TEM data, combined with regional hydrologic data, indicate that the caldera in hydrologically isolated from the surrounding region, with as much as 60 m of difference in elevation of the groundwater table across caldera-bounding faults. The water-table information and estimates of fluxes of water through the system were used to constrain a numerical simulation of groundwater flow. The simulation results indicate that basalt flows in the outer parts of the caldera have a relatively high transmissivity, whereas the central edifice has a substantially lower transmissivity. A layer of relatively high transmissivity must be present at depth within the edifice in order to deliver the observed flux of water and steam to the active vent. This hydrologic information about the caldera provides a baseline for assessing the response of this isolated groundwater system to future changes in magmatic activity.

The application of a DC electric field down gradient to the contaminated zone in the subsurface can create an electrokinetic barrier. The electrical potential gradient causes the movement of ions which in turn imposes a viscous drag on... more

The application of a DC electric field down gradient to the contaminated zone in the subsurface can create an electrokinetic barrier. The electrical potential gradient causes the movement of ions which in turn imposes a viscous drag on the pore water. In clayey soils, this viscous drag can generate a high enough pore water pressure capable of counteracting the ground water gradient. This phenomenon can be used effectively as a barrier to prevent contaminant migration. A finite element model was developed to simulate the contaminant migration in soil under coupled hydraulic, electrical and chemical gradients. The model is also capable of predicting the associated changes in the soil like the pore water pressure, pH and voltage gradient as a function of time and distance from the electrode. This model was validated using the w experimental data presented by Yeung Yeung, A.T., 1990. Electro-kinetic barrier to contaminant x transport through compacted clay. PhD Thesis, University of California, Berkeley, 260 pp. . The results indicate very good agreement between the experimental and simulated results. The model predications show that when the anode is placed down gradient of the cathode, the cation migration could be completely arrested. However, the anions were found to move faster in the direction of the ground water flow and reduce the effectiveness of the barrier. This could be avoided by carefully designing the placement of the electrodes. If the contaminant of interest is either a cation or an anion, a simple double row of anode and cathode electrode arrangement could serve as an effective barrier. On the other hand, if the contaminant includes both anions and cations, then a triple-row configuration of electrodes need to be implemented. The model ) Corresponding author. 0169-7722r00r$ -see front matter q 2000 Elsevier Science B.V. All rights reserved.

The southern slope of Merapi Volcano plays a significant role to recharge groundwater resources for Jogjakarta Municipality. Groundwater recharge, herein meant as the amount of effective precipitation that infiltrates into unsaturated... more

The southern slope of Merapi Volcano plays a significant role to recharge
groundwater resources for Jogjakarta Municipality. Groundwater recharge, herein meant
as the amount of effective precipitation that infiltrates into unsaturated zone and then
percolates as a water yield to water table after exceeds the soil field capacity, is the main
subject in this article. The objective of this research is to apply Water Table Fluctuation
(WTF) method to spatially define the groundwater annual recharge.
Four wells are selected to represent some geomorphologic units of southern
Merapi Volcano slope. Then, four Automatic Water Level Recorders were installed in
every well to record the yearly shallow groundwater table fluctuation with the intention
of achieving the spatial rate of groundwater recharge. The magnitude of groundwater
recharge is then defined by WTF method that requires groundwater fluctuation data and
specific yield.
The rate of groundwater recharge in every well confirms the varying value.
However, it seems that geomorphologic unit may be principally control to the time series
variation of shallow groundwater fluctuation that results in groundwater recharge
characteristic. The volcanic slope unit (above 600 m asl) has the lowest water table
fluctuation indicates the resistant comportment to the annual rainfall. This unit is
characterized by the relatively high magnitude of recharge of approximately 4270
mm/year.

Determination of chromium in groundwater samples containing iron may pose analytical problems due to sorption and fixation of chromium species onto Fe(III) hydroxides. Parks et al. (Water Res. 2004, 38, 2827) hypothesized that chromium... more

Determination of chromium in groundwater samples containing iron may pose analytical problems due to sorption and fixation of chromium species onto Fe(III) hydroxides. Parks et al. (Water Res. 2004, 38, 2827) hypothesized that chromium species trapped inside Fe(III) hydroxides i.e. "fixed chromium" may not be soluble by HNO 3 digestion (APHA method 3030 B). In such cases, hydroxylamine digestion is required to release "fixed chromium". To verify the hypothesis, we carried out this study on groundwater samples containing chromium and iron, using different methods of APHA and EPA. The results showed the presence of "fixed chromium", ranged between 0.1 and 19.2 μg L − 1 , contributing 0.2 to 14.1% towards true total chromium. Digestion of samples with HNO 3 released Cr(III) bound to organic complexes, but not the "fixed chromium". The hydroxylamine digestion released "fixed chromium", but not the Cr(III) bound to organic complexes. Microwave digestion of samples with HNO 3 + HCl was effective for the release of both "fixed" and "Cr(III)-organic complexes". Cr(III) was only adsorbed onto suspended matter, whereas Cr(VI), and Cr (III)-organic complexes were not adsorbed onto suspended matter due to their solubility. Sample pH, buffering capacity, and matrix have a significant influence on the adsorption and fixation of chromium species onto Fe(III) hydroxides.

It has been predicted that sea level will rise about 0.8 m by 2100. Consequently, seawater can intrude into the coastal aquifers and change the level of groundwater table. A raise in groundwater table due to seawater intrusion threats the... more

It has been predicted that sea level will rise about 0.8 m by 2100. Consequently, seawater can intrude into the coastal aquifers and change the level of groundwater table. A raise in groundwater table due to seawater intrusion threats the coastal infrastructure such as road pavements. The mechanical properties of subgrade materials will change due to elevated rise of groundwater table, leading to pavement weakening and decreasing the subgrade strength and stiffness. This paper presents an assessment of the vulnerability of subgrade in coastal areas to change in groundwater table due to sea-level rise. A simple bathtub approach is applied for estimating the groundwater level changes according to sea-level rise. Then the effect of groundwater level changes on the soil water content (SWC) of a single column of fine-sand soil is simulated using MIKE SHE. The impact of an increase in moisture content on subgrade strength/stiffness is assessed for a number of scenarios.

The groundwater quality of Wadi Al Arab aquifer, northwest Jordan, was assessed for its high molybdenum concentrations, which reach 1.62 mg/L. This value of Mo-concentration was far beyond the Jordan Institution for Standards and... more

The groundwater quality of Wadi Al Arab aquifer, northwest Jordan, was assessed for its high molybdenum concentrations, which reach 1.62 mg/L. This value of Mo-concentration was far beyond the Jordan Institution for Standards and Metrology (JISM) and World Health Organization (WHO) guidelines. Hydro-geochemical studies were carried out in order to assess the chemistry of the groundwater quality focusing on identifying the hydrogeo-chemical processes and mechanisms that are involved in the high Mo concentration. The water quality data of Wadi Al Arab boreholes (1986-2018) was collected, and the dataset analyzed. Interpretation of hydrochemical data showed that the anions are dominated by 3 HCO − with abundance order of 3 HCO − > 2 4 SO − > Cl − > 3 NO − , while the main cation is Ca 2+ , with abundance order of Ca 2+ > Mg 2+ > Na + > K + ; water type is 3 Ca-HCO −. The reason is the passage of groundwater through carbonate rocks. The distribution of the sampling points in the Gibbs diagram showed that the majority of samples are plotted within the field of rock weathering, which indicates that the main factor controlling dissolved hydrochemical components of the water samples is the dissolution of the rock-forming minerals. The scattered plot of the Mo with other critical heavy metals shows two different trend lines suggesting initiation of molybdenum to groundwater which is probably derived from oil shale and phosphate. The effects of pH and redox potential on Mo mobility in water are reviewed using the paurbaix diagram. The Mo species of the sampled wells are confined to the field of () 2 4 MoO − : anoxic/non-sulfidic condition (Fe reduction) which is located in the unconfined part of the aquifer, and () s 2 MoS which is sulfidic condition (low and high) in the confined aquifer. How to cite this paper: Hiasat, T.H., Ri-mawi, O.A. and Makhlouf, I.M. (2020) Hydrochemical Evaluation of Molybdenum

When large-scale irrigation schemes were created, establishing viable, and closely supervised, medium-sized family farms was considered essential to reap the benefits of state investments. This centralized development model was... more

When large-scale irrigation schemes were created, establishing viable, and closely supervised, medium-sized family farms was considered essential to reap the benefits of state investments. This centralized development model was progressively dismantled, especially as farmers installed private tubewells relying less on surface water. Our aim is to analyse development pathways of family farms in the Tadla irrigation scheme (Morocco). Results showed that pathways were linked to groundwater access, but also to (informal) land markets, and off-farm revenues. Groundwater enabled farmers to overcome reductions in surface water, and diversify crops. This concerned mainly the 36% large and medium-sized farms. Such farmers also managed to increase their cropped area through land markets, as renting in land, and producing market crops, require capital. Groundwater showed limited redistributive capacities, as only 20% of small-scale farmers obtained direct access. Farmers' off-farm revenues sustained livelihoods, especially in dry years, but were generally not reinvested in agriculture. Over the past 40 years, groundwater has been mainly mobilized from phreatic aquifers, recharged by rainfall and surface irrigation. Their use seems sustainable, but farmers are exploring deeper aquifers while the administration encourages conversion to micro-irrigation, thus reducing aquifer recharge and complicating the future of the groundwater economy.

B.L. Hall . 0304-3894r00r$ -see front matter q 2000 Elsevier Science B.V. All rights reserved.

The ERA-NET co-financing action of 32 European countries led to the establishment of the European research area on geological surveys to provide a geological service for Europe (GeoERA). GeoERA consisted of 15 projects lasting 3 years and... more

The ERA-NET co-financing action of 32 European countries led to the establishment of the European research area on geological surveys to provide a geological service for Europe (GeoERA). GeoERA consisted of 15 projects lasting 3 years and was launched in July 2018. The final online conference was held in January 2022 and the results of all projects were presented and discussed with a large group of stakeholders.
All the complete GIS viewer projects are available at https://geoera.eu and a short video describes the mega project https://youtu.be/zqBpgpDmCQA .
With the Hotlime project, the atlas of the geothermal basins of carbonate rocks throughout Europe was obtained for 11 study areas. For all areas, spatial evaluations were made in 500 x 500m raster cells. The evaluation of the quantity of stored heat, that is the maximum theoretically extractable thermal energy in the reservoir, is one of the main results of the mapping and characterization of the deep carbonate reservoirs of HotLime. For its direct comparison, this map shows the volumetric Heat in Place expressed in GJ/m2 (109 J/m2) calculated for volumes of 500 mx 500 m gross tank thickness [m] and the reference temperature Tref = 18°C. Taking into account national starting conditions, the Heat in Place maps are not intended to offer instructions for project developers to build geothermal wells, but to indicate the overall potential of a region and identify areas for further localized investigations for geothermal exploration with promising values.
With the Mintell4EU project it was possible to obtain data on the production and trade of mineral raw materials for 40 European countries, exploration data for 7 European countries available for research purposes, problem solving for planning, programming and design activities on a regional, national and European scale. The Geological Office of the Umbria Region has prepared a specific addition to the database, in compliance with the INSPIRE legislation, and this integrated database is one of the results of the project. For all the Umbrian mining sites, the integrated database now has a wealth of information ranging from the lithological description to the natural radioactivity content of the raw materials as well as of all the rocks present in Umbria. This information is available to the community and can also be used by all commercial operators.
With the Resource project it was possible to obtain a standardization of the ways of representing groundwater as a resource at pan-European level for the areas under analysis. For the Valle Umbra, information is now available regarding the strategic resource of the underground waters of the Umbrian valley (quantity, depth, transmittivity, etc.).

In developing countries, the rapid urbanization in the second half of the twentieth century provoked radical changes in the cities with serious water related problems, such as freshwater scarcity, sewage and drainage problems. This growth... more

In developing countries, the rapid urbanization in the second half of the twentieth century provoked radical changes in the cities with serious water related problems, such as freshwater scarcity, sewage and drainage problems. This growth produced several impacts on groundwater resources such as land impermeabilization and change in groundwater recharge, excessive exploitation and groundwater pollution. These facts have demanded better planning and management, especially in areas with high dense population. In Brazil, water legislation has been approved by parliament, a water agency has been created and technical knowledge of water resources has improved. Management strategies incorporated several issues: planning, legislation, zoning, licensing, concession and controlling. Monitoring, hydrochemical analyses and groundwater modeling have been performed to obtain more information for better management towards sustainability.

O lixão do jóquei clube foi o maior do Brasil e da América Latina, sendo potencial fonte de contaminação das águas subterrâneas através do chorume que percola pelo solo até o lençol freático. Este trabalho busca entender a dimensão da... more

O lixão do jóquei clube foi o maior do Brasil e da América Latina, sendo potencial fonte de contaminação das águas subterrâneas através do chorume que percola pelo solo até o lençol freático.
Este trabalho busca entender a dimensão da diminuição na qualidade da água subterrânea das adjacências do lixão da estrutural, através de uma pesquisa bibliográfica e uma comparação entre águas colhidas de um poço artesiano nas redondezas do aterro com águas colhidas em uma região sem fontes de contaminação.
O presente trabalho analisou 10 parâmetros: acidez, dureza em relação ao cálcio e em relação ao magnésio, teor de sódio e de potássio, teor de cloreto, condutividade elétrica, sólidos totais, sólidos solúveis e sólidos suspensos; usando técnicas volumétricas, gravimétricas e fotométricas.
Os resultados do presente trabalho foram congruentes com os resultados de estudos anteriores.

Column experiments were performed to examine (a) the potential for leachate from construction and demolition (C&D) debris landfills to mobilize naturally-occurring iron and arsenic from soils underlying such facilities and (b) the ability... more

Column experiments were performed to examine (a) the potential for leachate from construction and demolition (C&D) debris landfills to mobilize naturally-occurring iron and arsenic from soils underlying such facilities and (b) the ability of crushed limestone to remove these aqueous phase pollutants. In duplicate columns, water was added to a 30-cm layer of synthetic C&D debris, with the resulting leachate serially passed through a 30-cm soil layer containing iron and arsenic and a 30-cm crushed limestone layer. This experiment was conducted for two different soil types (one high in iron (10,400 mg/kg) and the second high in iron (5400 mg/kg) and arsenic (70 mg/kg)); also monitored were control columns for both soil types with water infiltration alone. Despite low iron concentrations in the simulated C&D debris leachate, elevated iron concentrations were observed when leachate passed through the soils; reductive dissolution was concluded to be the cause of iron mobilization. In the soil containing elevated arsenic, increased iron mobilization from the soil was accompanied by a similar but delayed arsenic mobilization. Since arsenic sorbs to oxidized iron soil minerals, reductive dissolution of these minerals results in arsenic mobilization. Crushed limestone significantly reduced iron (to values below the detection limit of 0.01 mg/L in most cases); however, arsenic was not removed to any significant extent.

Abstract: Lineaments are mapable linear surface features, which presumably reflect subsurface phenomena. The study demonstrates the use of ALOS imagery for lineament mapping for geological application. The image was enhanced and used for... more

Abstract: Lineaments are mapable linear surface features, which presumably reflect subsurface phenomena. The study demonstrates the use of ALOS imagery for lineament mapping for geological application. The image was enhanced and used for lineaments extraction through on-screen digitising. The extracted lineaments were evaluated against the published geological map for the study area using GIS overlay operation. Statistical analyses were carried to determine lengths, densities and intersections of the lineaments. The results show that the interpreted lineaments from ALOS imagery and ancillary data closely correlate with the faults shown on the published geological map (in 1974) of the study area. Key words: Lineament, Hydrogeology, Mapping, Remote Sensing, Information Extraction, Image Enhancement, Statistical Analysis, Multispectral Image

The Tuscany region of Italy is widely affected by subsidence, landslides and floods, which severely impact buildings and infrastructure. In particular, Firenze-Prato-Pistoia basin has a long experience of ground deformation related to... more

The Tuscany region of Italy is widely affected by subsidence, landslides and floods, which severely impact buildings and infrastructure. In particular, Firenze-Prato-Pistoia basin has a long experience of ground deformation related to groundwater withdrawal. European remote-sensing satellite (ERS) data collected since 1992 have revealed the presence of several subsiding areas in the basin such as the south-eastern portion of the city of Pistoia. Sentinel-1 persistent scatterer interferometry (PSI) measurements for 2015–2018 confirmed the long-term subsidence of this area, associated with intense horticulture (plant nurseries). At the same time, Sentinel-1 data revealed the unexpected movement of Pistoia historic center, which has always been considered stable in the past. To identify the complex relationship between aquifer conditions and ground displacement, a hydrogeologic model of the Pistoia aquifers was developed, applying an integrated modelling procedure. Hydrodynamic-paramet...

Assessing the vulnerability of groundwater is the first step toward careful management of water resources to avoid or, at least, to minimize impacts on agriculture. The objective of this study was to propose a simple method to assess the... more

Assessing the vulnerability of groundwater is the first step toward careful management of water resources to avoid or, at least, to minimize impacts on agriculture. The objective of this study was to propose a simple method to assess the groundwater quality and to map its spatial variation in terms of suitability for irrigation in the Darb El-Arbaein area, Southwestern Desert, Egypt. Thirty-six surveyed wells were used to assess and map the groundwater quality. For calculating the Water Quality Index (WQI), a total of 20 (13 chemical, two physical, and five calculated) parameters were considered e.g., EC, pH, Cl, SAR, B, Zn, iron, Mn, Pb and Cd. The results of analyses were used to propose a water quality model. The different water quality maps were produced using GIS software. The results show that three water samples fall into the moderate WQI. Most of the samples (26) fall into the unsuitable WQI category. Seven samples fall into the suitable WQI category. Groundwater samples that fall into the low salinity hazard class and high WQI can be used for irrigation of most crops and the majority of soils. The WQI for the samples ranges from 47.9 to 88.6. The WQI distribution maps delineating an area of 266.66 ha are suitable for irrigation in villages (3,4) and areas of 382.35 ha are moderately suitability for villages (1,2). Since the final map shows the spatial distribution of irrigation water quality in the area, it is now much easier for a decision maker to assess the water quality for irrigation and to locate the most suitable site for drilling wells. The present study demonstrates high efficiency for GIS to analyze complex spatial data and groundwater quality mapping.

Water wells (n = 116) overlying the Eagle Ford, Fayetteville, and Haynesville Shale hydrocarbon production areas were sampled for chemical, isotopic, and groundwater-age tracers to investigate the occurrence and sources of selected... more

Water wells (n = 116) overlying the Eagle Ford, Fayetteville, and Haynesville Shale hydrocarbon production areas were sampled for chemical, isotopic, and groundwater-age tracers to investigate the occurrence and sources of selected hydrocarbons in groundwater. Methane isotopes and hydrocarbon gas compositions indicate most of the methane in the wells was biogenic and produced by the CO2 reduction pathway, not from thermogenic shale gas. Two samples contained methane from the fermentation pathway that could be associated with hydrocarbon degradation based on their co-occurrence with hydrocarbons such as ethylbenzene and butane. Benzene was detected at low concentrations (<0.15 μg/L), but relatively high frequencies (2.4-13.3% of samples), in the study areas. Eight of nine samples containing benzene had groundwater ages >2500 years, indicating the benzene was from subsurface sources such as natural hydrocarbon migration or leaking hydrocarbon wells. One sample contained benzene ...

The aim of the analysis was to assess the intrinsic and specific vulnerability of groundwater to pollution from pesticides in Ireland at the national scale. A methodology to incorporate the effect of groundwater recharge in vulnerability... more

The aim of the analysis was to assess the intrinsic and specific vulnerability of groundwater to pollution from pesticides in Ireland at the national scale. A methodology to incorporate the effect of groundwater recharge in vulnerability assessment is described which can be particularly useful for the evaluation of dilution of groundwater pollutants. A sensitivity analysis using Monte-Carlo simulation revealed that the most important parameters of the model were subsoil (r ¼ 0.79) and topsoil (r ¼ 0.72), which is in agreement with the current knowledge of the parameters that have a significant effect on groundwater vulnerability in Ireland. The intrinsic vulnerability assessment was verified using total organic carbon (TOC) concentration in groundwater, a novel approach for the validation of groundwater vulnerability methods at regional scales. A statistical analysis showed that TOC concentration was significantly different (p < 0.001) between watersheds classified as highly vulnerable and watersheds classified as less vulnerable, providing evidence that the developed method can effectively classify karst areas in terms of groundwater vulnerability.

Global warming, greenhouse effect, and the climate change problems are long-term anthropogenic consequences that are expected to threaten water related demand and supply patterns in the near future. These problems may be identified... more

Global warming, greenhouse effect, and the climate change problems are long-term anthropogenic consequences that are expected to threaten water related demand and supply patterns in the near future. These problems may be identified linguistically on a logical basis to take the necessary precautions, and implement mitigation strategies after vulnerability possibilities are assessed using fuzzy logic. Climate change effects are the focus of many scientific, engineering, economic, social, cultural, and global nuisances, and these effects awaits cost-effective remedial solutions. Extreme events such as floods and droughts and modified groundwater recharge may be influenced by climate change.

We evaluated several factors influencing the taxonomic richness of macrophytes, benthic invertebrates, snails, and fish in a series of northern Wisconsin lakes. We chose the study lakes to decouple the potential effects of ionic strength... more

We evaluated several factors influencing the taxonomic richness of macrophytes, benthic invertebrates, snails, and fish in a series of northern Wisconsin lakes. We chose the study lakes to decouple the potential effects of ionic strength of lake water and stream connection, two factors that are usually highly correlated and therefore have been confounded in previous studies. In addition, our study lakes covered a wide range in a variety of characteristics, including residential development, abundance of exotic species, nutrient concentrations, predator abundance, and lake size. Species richness within each of the four taxonomic groups was significantly positively related to ionic strength (as measured by specific conductance); we also found secondary associations with other variables, depending on the specific group of organisms. The relationship between richness and lake area was dependent on the specific conductance of the lake and the vagility of the organisms; less vagile groups of organisms showed stronger and steeper species–area relationships in low-conductivity lakes. Further, after variance owing to specific conductance was removed, the presence of stream connections was positively related to species richness for fish, snails, and macrophytes as well as familial richness in benthic invertebrates. Our results indicate that lakes with relatively more groundwater input have lower extinction rates for all four groups of taxa and that lakes with stream inlets and outlets have enhanced immigration rates for fish, snails, benthic invertebrate families, and macrophytes. These findings link processes of immigration and extinction of four groups of organisms of varying vagility to landscape-level hydrologic characteristics related to the glacial history of the region.

Intake of water with high concentration of nitrate is a major problem in many countries as it affects health of humans. The present study was carried out with the objective of determining the causes for higher nitrate concentration in... more

Intake of water with high concentration of nitrate is a major problem in many countries as it affects health of humans. The present study was carried out with the objective of determining the causes for higher nitrate concentration in groundwater in parts of Nalgonda district, Andhra Pradesh, India. The study area is located at a distance of about 135 km towards ESE direction from Hyderabad. Nitrate concentration in groundwater of this area was analysed by collecting groundwater samples from 46 representative wells. Samples were collected once in two months from March 2008 to January 2009. The nitrate concentration was analysed in the laboratory using Metrohm 861 advanced compact ion chromatograph using appropriate standards. The highest concentration recorded during the sampling period was 879.65 mg/L and the lowest concentration was below detection limit. Taking into consideration 45 mg/L of nitrate as the maximum permissible limit for drinking water set by BIS, it was found that ...

Recent studies have confirmed significant tree-mediated methane emissions in wetlands; however, conditions and processes controlling such emissions are unclear. Here we identify factors that control the emission of methane from Alnus... more

Recent studies have confirmed significant tree-mediated methane emissions in wetlands; however, conditions and processes controlling such emissions are unclear. Here we identify factors that control the emission of methane from Alnus glutinosa.

Groundwater chemistry and isotopic data from 40 production wells in the Atemajac and Toluquilla valleys, located in and around the Guadalajara metropolitan area, were determined to develop a conceptual model of groundwater flow processes... more

Groundwater chemistry and isotopic data from 40 production wells in the Atemajac and Toluquilla valleys, located in and around the Guadalajara metropolitan area, were determined to develop a conceptual model of groundwater flow processes and mixing. Stable water isotopes (δ 2 H, δ 18 O) were used to trace hydrological processes and tritium (3 H) to evaluate the relative contribution of modern water in samples. Multivariate analysis including cluster analysis and principal component analysis were used to elucidate distribution patterns of constituents and factors controlling groundwater chemistry. Based on this analysis, groundwater was classified into four groups: cold groundwater, hydrothermal groundwater, polluted groundwater and mixed groundwater. Cold groundwater is characterized by low temperature, salinity, and Cl and Na concentrations and is predominantly of Na-HCO 3-type. It originates as recharge at "La Primavera" caldera and is found predominantly in wells in the upper Atemajac Valley. Hydrothermal groundwater is characterized by high salinity, temperature, Cl, Na and HCO 3 , and the presence of minor elements such as Li, Mn and F. It is a mixed-HCO 3 type found in wells from Toluquilla Valley and represents regional flow circulation through basaltic and andesitic rocks. Polluted groundwater is characterized by elevated nitrate and sulfate concentrations and is usually derived from urban water cycling and subordinately from agricultural return flow. Mixed groundwaters between cold and hydrothermal components are predominantly found in the lower Atemajac Valley. Twenty-seven groundwater samples contain at least a small fraction of modern water. The application of a multivariate mixing model allowed the mixing proportions of hydrothermal fluids, polluted waters and cold groundwater in sampled water to be evaluated. This study will help local water authorities to identify and dimension groundwater contamination, and act accordingly. It may be broadly applicable to other active volcanic systems on Earth.

The Bundelkhand region in India has been dealing with a severe water crisis for the last two decades. This water crisis has received a significant amount of attention from the central government, media and academics. However, although... more

The Bundelkhand region in India has been dealing with a severe water crisis for the last two decades. This water crisis has received a significant amount of attention from the central government, media and academics. However, although multiple policies and acts have been passed, and extensive resources distributed, there has not been much improvement on the ground. This thesis analyzes the reasons behind ineffective water governance and implementation at all levels of government, and concludes that over-centralization of planning, crisis-response rather than long-term planning, and a lack of pragmatic planning are key to understanding the current situation. More generally, the disjointed nature of water governance in India has made it difficult for the public sector to carry out cohesive planning approaches. We suggest reforms that can be adopted, and consider the possible consequences to water management and planning if Bundelkhand were to become a separate state.

The paper is based on 237 chemical analysis of groundwater, where the determination of magnesium origin in groundwatersof northeastern Bosnia were performed. The determination of magnesium origin in groundwaterswere carried through on the... more

The paper is based on 237 chemical analysis of groundwater, where the determination of magnesium origin in groundwatersof northeastern Bosnia were performed. The determination of magnesium origin in groundwaterswere carried through on the basis of Mandel & Shiftan classification. Based on the results, a distribution map of Mg 2+ ions in groundwaters in northeastern Bosnia were drafted.

When estimating the time since death or manner of death, the identification and the pathological evaluations of a body are generally impeded by post mortem changes. Research and case studies help experts to achieve a more accurate... more

When estimating the time since death or manner of death, the identification and the pathological evaluations of a body are generally impeded by post mortem changes. Research and case studies help experts to achieve a more accurate diagnosis, but at present there is scant literature covering topics concerning forensic science and decompositional processes in aquatic environments. The two case studies presented each involve a decomposed body found in a unique aquatic environment; namely wells containing ground water. In Case 1 an entomologist attended the scene and in Case 2 an entomologist was only involved after 20 months when it was decided that the insect evidence collected at the second autopsy may be useful in determining a time frame. The first case highlights the problems associated with body retrieval from aquatic environments as the body was removed it dismembered. Fortunately, the well was able to be drained, so much of the insect evidence was retrieved. In the second case the body was found dismembered but the entomological evidence was overlooked and lost. During the second autopsy insects were found, collected, and sent to an entomologist to help clarify the post mortem interval.

Coastal Zone Act Reauthorization Amendments (CZARA, Section 6217) necessitate the requirement that onsite wastewater disposal units located near impaired surface waters or groundwater to provide at least 50% nitrogen removal.... more

Coastal Zone Act Reauthorization Amendments (CZARA, Section 6217) necessitate the requirement that onsite wastewater disposal units located near impaired surface waters or groundwater to provide at least 50% nitrogen removal. Approximately 38% of Hawaii households use onsite systems including septic tanks and cesspools that cannot meet this requirement. Upgrades to aerobic treatment units (ATUs) are a possible compliance solution. In Hawaii, ATUs must meet National Sanitation Foundation Standard 40 (NSF40) Class I effluent criteria. Previously, a multi-chamber, flowthrough, combined attached/suspended growth type ATU (OESIS-750) and presently, a sequencing batch type ATU (CBT 0.8KF-210) were evaluated for NSF40 compliance, nutrient removal capability (NSF245), and adaptability for water reuse (NSF350). Both units easily achieved the NSF40 Class I effluent criteria. While the OESIS-750 achieved only 19% nitrogen removal, the CBT unit achieved 81% nitrogen removal, meeting the NSF245 criteria and CZARA requirements for applications in critical wastewater disposal areas. In addition, the CBT consistently produced effluent with turbidity less than 2 NTU (NSF350) and UVT 254 greater than 70%, facilitating the production of unrestricted-use recycled water.

Barind Tract of Bangladesh is one of the driest parts of the region where surface water supplies are limited. Large parts of this tract used to be fallow land because there were no major irrigation facilities until mid 1980s. A detailed... more

Barind Tract of Bangladesh is one of the driest parts of the region where surface water supplies are limited. Large parts of this tract used to be fallow land because there were no major irrigation facilities until mid 1980s. A detailed hydro geological and groundwater survey of Bangladesh was implemented by UNDP in February 1978; Barind was described as follows, “the zone lie on the western Rajshahi known as Barind Tract. Thick clay deposits have been proven by test drilling which indicates that the main aquifer does not exist in the upper 300 m. Therefore groundwater potential is limited to development from relatively thin, fine grained sand zones that appear within the clay sequence. The aquifer is capable of supporting only small domestic needs”. The above mentioned theoretical study result of UNDP is surpassed by the innovation of “INVERTED WELL”. This was the outcome of the actual field trials to meet the local need and match available aquifer conditions that was not suitable ...