Variable Groundwater Research Articles

Assessment and spatial mapping of water quality parameters using QGIS: Creating a dynamic map

ABSTRACT Groundwater is a critical resource for drinking, irrigation, and industrial purposes, making up 30.1% of global freshwater. Ensuring its quality is vital for human health due to the risks of contamination. Effective management and monitoring of groundwater are essential, particularly in regions like Peninsular Malaysia where groundwater constitutes a significant water source. This study aims to generate and assess the spatial distribution of the groundwater quality index (GWQI) using quantum GIS (QGIS), perform a spatiotemporal analysis from 2014 to 2022, and develop a dynamic map for public accessibility. Addressing the need for efficient and cost-effective monitoring methods, this research moves beyond traditional resource-intensive approaches by leveraging QGIS for spatial interpolation. The goal is to provide a preliminary assessment method into groundwater quality trends and facilitate better resource management in Peninsular Malaysia. The study used historical groundwater quality data from 2014 to 2022, with QGIS software and the QGIS2Web plugin to create spatial and dynamic maps. The GWQI spatial distribution was generated using the inverse distance weighted method, and data were visualized through static and dynamic web maps hosted online for easy access. Overall, the study indicated stable but regionally variable groundwater quality, necessitating continued monitoring and targeted interventions.

Mobility of trace elements in a coastal contaminated site under groundwater salinization dynamics

Water pollution is a significant issue resulting from past long-term actions. The remediation projects carried out under law constraints for industrial plants, which have been the major contributors to environmental and water pollution, are currently providing a significant amount of data about contaminated soil, surface waters, and groundwater. Most of such plants worldwide are in coastal zones. Based on a significant amount of chemical and environmental data for a coastal contaminated site subject to variable groundwater salinization, this study aimed to understand the mobility of some trace elements because of coastal zone dynamics. Data concerned 688 groundwater samples, including As, Hg, Cd, Crtot, Cu, Ni, Pb, V, Se, Zn, pH, electrical conductivity, chlorides, total organic carbon and organic contaminants as quantitative variables, enhanced by additional qualitative variables such as groundwater salinity, season, water level, precipitation, and industrial activity type to make the dataset as representative as possible of the site under investigation. The study used robust multivariate statistical analyses to analyse the complex dataset and explain the relevant factors influencing contaminant behaviour under different environmental conditions. The Multivariate Statistical Analysis distinguished three clusters of trace elements with diverse reactivity to changes in groundwater salinization. The first includes Se, Cu, Crtot, V, and Ni, showing the highest correlation with electrical conductivity and chlorides because of their high affinity to form chloride or organic chloride complexes and for ion competition. Zn and Pb cluster in the second group: they are less reactive to groundwater salinization and more influenced by cation and anion competition and organic matter. The mobility of Hg and As (third cluster) significantly correlates with Fe and Mn, underlining the dominant role of reductive dissolution of trace elements-bearing minerals (Fe/Mn/Al-oxy-hydroxides) and metal-organic complexes. The correlation between the clustering of variables in groundwater and soils shows the influence of sediment structure, mineral composition, and physical and chemical soil conditions on the distribution in soils of trace elements and their transport to groundwater. The study proposes a valuable approach for assessing the effects of salinization in contaminated coastal aquifers. It supports planning multi-purpose characterization and monitoring campaigns of contaminated coastal sites and provides guidance on the correct associated remediation projects.

Spatial and temporal dynamics of groundwater biogeochemistry in the deep subsurface of a high-energy beach

Intertidal sandy beach systems are considered complex biogeochemical reactors. At beach sites that are subject to high tidal and wave energy, seawater circulation can reach tens of meters deep into the subsurface and changing environmental conditions are assumed to lead to dynamic groundwater flow paths, saltwater-freshwater mixing zones, and a spatio-temporally variable groundwater biogeochemistry. Previous studies mainly focused on the upper meters of subterranean estuaries (STE), while the deep subsurface remained a black box. This study presents spatial (cross-shore) and temporal (∼ six-weekly, over 1.5 years) dynamics of the groundwater biogeochemistry that were observed down to 24 m below the ground surface (mbgs) of a sandy high-energy beach on Spiekeroog Island (Germany).In addition to redox conditions along a cross-shore transect ranging from oxic to Fe oxide reducing/slightly sulfidic, we found a previously unknown, distinct vertical redox zonation as well. Temporal variations of the biogeochemistry within low salinity groundwater at the most landward station close to the dune base were mainly driven by storm flood related seawater infiltration. Around the high water line, the extent of the upper saline plume (USP) varied over time. Furthermore, temporal dynamics of the O2 saturation at 6 mbgs indicated a seasonally shifting depth of the oxycline at this location. In the lower intertidal zone, groundwater solute concentrations displayed a temporally variable zone of deep freshwater discharge.Regarding the impact of the deep STE on the groundwater biogeochemistry of the discharge zone, our data revealed that nutrient, Mn, and Fe release along the deep flow paths through the USP towards the discharge zone was limited, likely due decreasing availability of labile organic matter and subsequent slowing down of metabolic processes with depth. High concentrations of metabolites in the upper ∼ 2 mbgs of the discharge zone were, therefore, rather attributed to the incorporation of labile organic matter during continuous and storm flood related sediment relocation and/or the contribution of older waters, e.g., the subtidal saltwater wedge.

Interaction regimes of surface water and groundwater in a hyper-arid endorheic watershed on Tibetan Plateau: Insights from multi-proxy data

The interaction between surface water and groundwater is crucial for the management of water resources and the preservation of ecosystems within arid basins, but knowledge on their interaction regimes at the watershed scale remains relatively limited. The present research synthesizes a range of multi-proxy data, including satellite thermal infrared remote sensing, water piezometric level, hydrochemical analyses, and isotopic signatures (2H, 18O and 222Rn), to elucidate the interaction dynamics and patterns between surface water and groundwater within a representative hyper-arid closed basin on Tibetan Plateau. The findings indicate that the water in the basin originates primarily from the glacier/snow melt water and precipitation in the mountainous regions, and would experience multiple but spatially heterogeneous interactions between river and aquifers from the mountain pass to the tail salt lakes after entering the basin. Water interaction in the piedmont alluvial plain is dominated by the pattern of river seepage into aquifers with a water flux of 25.82 m3/s, which drives the development of hierarchical groundwater flow systems in the basin. The interaction pattern converts to groundwater discharge of the local groundwater flow system at the front of alluvial fan plain, which forms the principal spring-fed rivers and the predominant overflow zone in the basin with the groundwater discharge flux of 3.22 m3/s. Most of these discharged groundwaters would infiltrate back into the aquifers in the middle-upper part of the loess plain with the river water leakage flux of 2.89 m3/s. River water and phreatic groundwater present a gradual enrichment of hydrochemcial components and water stable isotopes (2H and 18O) along the flow path due to the intense evaporation in the loess plain. The multiple water interactions between surface water and groundwater lead to the anomalous distribution of fresh water in the middle-lower stream area, which is related to the intermediate groundwater flow system and the local variable groundwater flow system. Water interaction in the lowest salt-marsh plain is in the pattern of regional groundwater flow system discharge into the tail salt lakes under natural condition, but evolves to only discharge into the artificial brine extraction canals rather than the tail salt lakes after decades of brine exploitation. Our findings provide a conceptual and preliminarily quantificational understanding of the interaction regimes between surface water and groundwater in large arid closed basins at the watershed scale.

An integrated appraisal of the hydrogeochemistry and the potential public health risks of groundwater nitrate and fluoride in eastern Ghana

To understand groundwater pollution and its associated health hazards and to ensure the availability of a clean, safe, and sustainable water supply, comprehensive research plays a crucial role. This article presents an integrated investigation of groundwater conditions, hydrogeochemistry, and health implications arising from fluoride (F⁻) and nitrate (NO₃⁻) contamination in eastern Ghana. Analysis of 107 samples revealed variable groundwater suitability for human consumption, as indicated by Pollution Index of Groundwater (PIG) values ranging from 0.11 to 1.19. The study highlights significant variations in health hazard risks due to F⁻ and NO₃⁻ exposure. Hazard indices (HIs) for nitrate ingestion range from 0.000 to 16.321, for fluoride ingestion from 0.000 to 17.426, and for the combined ingestion risks from 0.000 to 17.602. Dermal absorption risk for nitrate is minimal, with values between 0.000 and 0.049. Spatially distinct contamination and health risks were mapped using GIS, to pinpoint vulnerable localities in the study region. Hydrochemical investigations, confirmed by clustering and factor analyses, revealed that natural geological processes are the primary drivers of groundwater quality and mineralization, with limited anthropogenic impacts. Further, an artificial neural network model with an impressive R2 of 0.976 and low statistical errors demonstrated strong potential for accurate prediction of groundwater quality. The holistic study approach significantly advances groundwater research in the region, paving the way for effective resource management strategies by revealing areas of concern, understanding the contamination drivers, and predicting future water quality with high accuracy.

Challenges of Including Wet Grasslands with Variable Groundwater Tables in Large-Area Crop Production Simulations

Large-scale assessments of agricultural productivity necessitate integrated simulations of cropland and grassland ecosystems within their spatiotemporal context. However, simultaneous simulations face limitations due to assumptions of uniform species distribution. Grasslands, particularly those with shallow groundwater tables, are highly sensitive to water availability, undergoing rapid species composition changes. We hypothesised that predicting above-ground biomass (AGB) remains challenging due to these dynamic responses. Ten years of data from four lysimeters at a German wet grassland site, with varying water table treatments, was utilised to test this hypothesis. Correlation analysis revealed a strong positive indirect effect of the water regime on AGB, with a one-year time lag (r = 0.97). The MONICA model initially exhibited fair agreement (d = 0.69) in simulating Leaf-Area-Index (LAI) but performed poorly in replicating AGB (d = 0.3). After removing the species composition change effect from the LAI and AGB datasets, the simulation notably improved, with the overall relative root mean square error (rRMSE) of AGB decreasing from 1.55 to 0.90 between the first and second simulations. This demonstrates MONICA’s ability to predict grass growth patterns amidst changing water supply levels for constant species composition. However, it needs a competition model to capture biomass growth changes with varying water supply.

Development of anthropogenic water regulation for Community integrated Earth System model (CIESM)

This study examines the impact of anthropogenic water regulation (AWR) on hydroclimatic systems by incorporating an AWR module into the Community Integrated Earth System Model (CIESM), validated against GRACE satellite data. This approach assesses the influence of human activities, including irrigation and groundwater extraction, on global and regional hydrology and climate. Key findings include: Implementation of the AWR module significantly improves terrestrial water storage (TWS) simulation accuracy in CIESM. The correlation coefficient for global-scale TWS improved from 0.33 in the control (CTRL) to 0.89 in the experiment (EXP). Notably, the model's performance enhanced in Northern India and the North China Plain, while the Central United States showed limited improvement. AWR markedly alters the global water cycle, evidenced by substantial increases in soil moisture (about 0.04 to 0.02 m3/m3) and evapotranspiration. These changes have led to increased latent heat flux (around 5 W/m2) and a decrease in temperature by 0.1 °C to 1 °C in heavily irrigated regions. The study highlights the role of AWR in modifying the energy balance, particularly in agricultural areas where irrigation exerts a significant cooling effect. Despite its potential, the study identifies considerable uncertainties in coupling AWR within the CIESM model, related to inherent model limitations, incomplete water intake data, variable groundwater levels, and simplifications in water transfer parameters. Future research should aim to refine these aspects, focusing on enhancing the physical mechanisms and performance of AWR modules in hydroclimatic simulations. In conclusion, this research underscores the substantial modifications in hydrological and climatic conditions due to human activities. The improved AWR scheme within CIESM provides valuable insights for understanding and predicting climate change impacts on water resources, demonstrating its utility in simulating complex hydroclimatic changes at both global and regional scales.

A numerical modelling approach to investigate the fate of brine reject of farm scale desalination plants on groundwater aquifers in arid environments

Farm-scale desalination units are gaining popularity for agricultural irrigation in arid countries, such as Kuwait to meet freshwater demands. However, less attention has been given to the management of environmentally hazardous brine reject water they produce. In this study we investigated the fate of brine water produced by the inland desalination units on the underlying aquifers using numerical modelling and field investigations. The methodology involved developing groundwater flow and solute transport models using Flex VMF-SEAWAT to simulate the movement of reject brine. The field investigations included collecting 150 water samples and conducting pumping tests on newly drilled wells. This numerical simulation considered advection, dispersion, and adsorption processes with variable groundwater density following rigorous validation and calibration of the developed numerical models. The results show that the RO reject brine will significantly increase groundwater salinity, exceeding 10,000 mg/L when accounting for advection, dispersion, and adsorption processes. The sustainable yield of the aquifer, with a salinity of <10,000 mg/L, averages 500 Mm3 but is expected to be depleted within 16 years with the current extraction rate. The resulting hydraulic properties are favourable with K about 100 m/d, T > 1000 m2/day, and Sy just >0.1. The adopted values for dispersivity and adsorption coefficients for chloride and sulphate salts in the aquifer were 10 m and 1 × 10−7 [mg/L]−1 respectively. Chemical and numerical analyses indicate a mixing ratio between the reject brine and groundwater in the study area of approximately 10 %. Uncontrolled groundwater extraction, combined with the surface disposal of RO reject brine, has led to a significant decline in groundwater levels and an increase in the salinity. The adsorption ratio of simulated brine plume was 13 %. The authors recommend to dispose the RO reject water in a safe location or transfer it to the nearest wastewater treatment plant for proper treatment and reuse.

Quantitative Groundwater Modelling under Data Scarcity: The Example of the Wadi El Bey Coastal Aquifer (Tunisia)

The Grombalia aquifer constitutes a complex aquifer system formed by shallow, unconfined, semi-deep, and deep aquifers at different exploitation levels. In this study, we focused on the upper aquifer, the Wadi El Bey coastal aquifer. To assess natural aquifer recharge, we used a novel physiography-based method that uses soil texture-dependent potential infiltration coefficients and monthly rainfall data. The developed transient flow model was then applied to compute the temporal variation in the groundwater level in 34 observation wells from 1973 to 2020, taking into account the time series of spatially variable groundwater recharge, artificial groundwater recharge from 5 surface infiltration basins, pumping rates on 740 wells, and internal prescribed head cells to mimic water exchange between the wadis and aquifer. The quantified deviations in the computed hydraulic heads from measured water levels are acceptable because the database used to construct a scientifically sound and reliable groundwater model was limited. Further work is required to collect field data to quantitatively assess the local inflow and outflow rates between surface water and groundwater. The simulation of 12 climate scenarios highlighted a bi-structured north‒south behaviour in the hydraulic heads: an increase in the north and a depletion in the south. A further increase in the pumping rate would, thus, be severe for the southern part of the Wadi El Bey aquifer.

Impact of Variable Water Chemistry on PFOS-Goethite Interactions: Experimental Evidence and Surface Complexation Modeling.

Perfluorooctanesulfonate (PFOS) has become a major concern due to its widespread occurrence in the environment and severe toxic effects. In this study, we investigate PFOS sorption on goethite surfaces under different water chemistry conditions to understand the impact of variable groundwater chemistry. Our investigation is based on multiple lines of evidence, including (i) a series of sorption experiments with varying pH, ionic strength, and PFOS initial concentration, (ii) IR spectroscopy analysis, and (iii) surface complexation modeling. PFOS was found to bind to goethite through a strong hydrogen-bonded (HB) complex and a weaker outer-sphere complex involving Na+ coadsorption (OS-Na+). The pH and ionic strength of the solution had a nontrivial impact on the speciation and coexistence of these surface complexes. Acidic conditions and low ionic strength promoted hydrogen bonding between the sulfonate headgroup and protonated hydroxo surface sites. Higher electrolyte concentrations and pH values hindered the formation of strong hydrogen bonds upon the formation of a ternary PFOS-Na+-goethite outer-sphere complex. The findings of this study illuminate the key control of variable solution chemistry on PFOS adsorption to mineral surfaces and the importance to develop surface complexation models integrating mechanistic insights for the accurate prediction of PFOS mobility and environmental fate.

On groundwater flow and shallow geothermal potential: A surrogate model for regional scale analyses

Many cities worldwide lay upon alluvial aquifers which have a great potential for low temperature geothermal installations thanks to the thermal diffusive properties of saturated porous media and the constant temperature of the subsurface. In addition, aquifers with fast moving groundwater have a higher potential due to the additional energy replenishment by advection, which is often underestimated.This work aims at bridging the gap between quantitative hydro-thermal numerical analysis and regional scale assessment developing a process-based surrogate model for the estimation of the thermal exchange (geothermal) potential of ground source heat pumps (GSHP) considering groundwater advection. The proposed method is based on a synthetic 3D FEM model reproducing the infinite line source configuration and introducing groundwater advection. Conductive/advective g-functions were derived from the numerically simulated space-time thermal perturbation for a comprehensive set of hydrogeological regimes, and a surrogate model was developed by a machine learning (ML) regression of the thermal response of the system. This solution, beyond the run time of the numerical study and the ML training phase, is very fast, applicable at any scale and scalable to any desired depth.The trained model can be used to predict the geothermal potential of GSHP for almost all sedimentary basins around the world upon the availability of the required input data (aquifer thickness and saturation, aquifer porosity and groundwater flow velocity). In this study, large scale geothermal potential maps were generated from input layers implemented in a GIS, for a demonstrative area in northern Italy showing highly variable groundwater flow (Darcy velocity from 10−3 to 10+3 m/y). A promising increase (up to +250 %) in the thermal exchange potential of GSHP due to the contribution of advection was highlighted discussing the benefits of groundwater flow and the amount of usable potential with implications on shallow geothermal energy management and development.

Wind-modulated groundwater discharge along a microtidal Arctic coastline

Groundwater discharge transports dissolved constituents to the ocean, affecting coastal carbon budgets and water quality. However, the magnitude and mechanisms of groundwater exchange along rapidly transitioning Arctic coastlines are largely unknown due to limited observations. Here, using first-of-its-kind coastal Arctic groundwater timeseries data, we evaluate the magnitude and drivers of groundwater discharge to Alaska’s Beaufort Sea coast. Darcy flux calculations reveal temporally variable groundwater fluxes, ranging from −6.5 cm d−1 (recharge) to 14.1 cm d−1 (discharge), with fluctuations in groundwater discharge or aquifer recharge over diurnal and multiday timescales during the open-water season. The average flux during the monitoring period of 4.9 cm d−1 is in line with previous estimates, but the maximum discharge exceeds previous estimates by over an order-of-magnitude. While the diurnal fluctuations are small due to the microtidal conditions, multiday variability is large and drives sustained periods of aquifer recharge and groundwater discharge. Results show that wind-driven lagoon water level changes are the dominant mechanism of fluctuations in land–sea hydraulic head gradients and, in turn, groundwater discharge. Given the microtidal conditions, low topographic relief, and limited rainfall along the Beaufort Sea coast, we identify wind as an important forcing mechanism of coastal groundwater discharge and aquifer recharge with implications for nearshore biogeochemistry. This study provides insights into groundwater flux dynamics along this coastline over time and highlights an oft overlooked discharge and circulation mechanism with implications towards refining solute export estimates to coastal Arctic waters.

Multicomponent PFAS sorption and desorption in common commercial adsorbents: Kinetics, isotherm, adsorbent dose, pH, and index ion and ionic strength effects

The adsorption and desorption of 9 PFAS, including 3 perfluoroalkyl sulphonic and 6 perfluoroalkyl carboxylic acids, in artificial groundwater was investigated using 3 commercial adsorbents that comprised a powdered activated carbon (PAC), a surface-modified organoclay (NMC+n), and a carbonaceous organic amendment (ROAC). Sorption kinetics and isotherms of PFAS, as well as the effects of adsorbent dose, pH, index ion and ionic strength on PFAS adsorption and desorption were investigated. Sorption of multicomponent PFAS in the adsorbents was rapid, especially for NMC+n and ROAC, regardless of PFAS chain length. The sorption and (and especially) desorption of PFAS in the adsorbents was impacted by the pH, index ion, and ionic strength of simulated groundwater, especially for the short chain PFAS, with only minimal impacts on NMC+n and PAC compared to ROAC. Although the potential mineral and charged constituents of the adsorbents contributed to the adsorption of short chain PFAS through electrostatic interactions, these interactions were susceptible to variable groundwater chemistry. Hydrophobic interactions also played a major role in facilitating and increasing PFAS sorption, especially in adsorbents with aliphatic functional groups. The desorption of PFAS from the adsorbents was below 8 % when the aqueous phase was deionised water, with no measurable desorption for NMC+n. In contrast, the desorption of short chain PFAS in simulated groundwater increased substantially (30–100 %) in the adsorbents, especially in ROAC and NMC+n, but more so with ROAC. In general, the three adsorbents exhibited strong stability for the long chain PFAS, especially the perfluoroalkyl sulphonic acids, with minimal to no sorption reversibility under different pH and ionic composition of simulated groundwater. This study highlights the importance of understanding not only the sorption of PFAS in groundwater using adsorbents, but also the desorption of PFAS, which may be useful for decision making during the ex-situ and in-situ treatment of PFAS-contaminated groundwater.

Insight into heat dissipation in fractured rock influenced by groundwater influx and heat source configurations using numerical analysis

The characterization and evaluation of heat dissipation effects in fractured rock is becoming a priority topic with respect to the potential application of low-temperature thermal remediation in these settings. A three-dimensional numerical model was utilized to investigate heat dissipation-related thermo-hydrological processes in an upper fractured rock layer and a lower impermeable bedrock layer. To identify the factors controlling spatial temperature variances in the fractured rock layer accounting for a scaled heat source and variable groundwater flow, global sensitivity analyses were conducted on the variables using three categories: heat source, groundwater flow, and rock properties. A discrete Latin-hypercube-one-at-a-time method was used to conduct the analyses. A heat dissipation coefficient was proposed to evaluate the correlation between heat dissipation effects and transmissivity based on a case study using the hydrogeological setting of a well-characterized Canadian field site. The results show a significance ranking of three sets of variables controlling heat dissipation processes in both the central and the bottom areas of the heating zone: specifically, heat source > groundwater > rock. The groundwater influx and heat conduction in the rock matrix are key factors determining heat dissipation at the upstream and bottom areas of the heating zone, respectively. The heat dissipation coefficient is closely associated with the transmissivity of the fractured rock in a monotonic relationship. A significant growth rate of the heat dissipation coefficient appears when the transmissivity is between 1 × 10−6 and 2 × 10−5m2/s. The results suggest that the low-temperature thermal remediation can be a promising technique to adapt the significant heat dissipation in highly weathered fractured rock.

Intra-annual patterns in biofilm communities and cellulose decomposition in a headwater stream network with spatially variable groundwater inputs

Intra-annual patterns in biofilm communities and cellulose decomposition in a headwater stream network with spatially variable groundwater inputs

Possible Zones of Submarine Groundwater Discharge (SGD) and Seawater Intrusion (SWI) along the West Coast of Kanyakumari, India

The possible zones of submarine groundwater discharge (SGD) and seawater intrusion (SWI) along the west coast of Kanyakumari in the southernmost Indian Peninsula were identified by integrating the surface temperature anomaly, water table fluctuation, and water quality analysis. Temperature map of the sea surface from Landsat 8 satellite data, which helped to demarcate SGD in areas with significant thermal contrast, exists between the seawater and discharging groundwater. Monitoring data of 2019–2021 illustrated patchy, diffuse, and temporally variable groundwater seepage. The spatial distribution map created from groundwater level, and water quality parameters depicted high SGD in areas of high groundwater level and high chances of SWI in regions with low groundwater level. This study identified that the areas with low groundwater level, high EC, and high chloride contents are prone to SWI. Similarly, the regions with high thermal contrast, high groundwater level, and low EC have more SGD. These methods have the potential to be used as preliminary screening tools before implementing detailed studies about the mixing process.

Predicting timescales of relaxation in the shallow Earth’s subsurface

Earthquakes introduce long-lasting transient mechanical damage in the subsurface, which cause postseismic hazards such as enhanced landsliding and can take years to recover to steady-state values. This observation has been linked to relaxation, a phenomenon observed in a wide class of materials after straining perturbations. In this presentation, I analyze the successive effect of two large earthquakes on ground properties through the monitoring of seismic velocity from ambient noise interferometry in the Atacama desert in Chile. The absence of rainfall in this area allows study of the mechanical state of the subsurface by limiting the potential effect of variable groundwater content. I show that relaxation timescales are a function of the current state of the subsurface when perturbed by earthquakes, rather than ground shaking intensity. Our study highlights the predictability of earthquake damage dynamics in the Earth's near-surface and potentially other materials. I propose to reconcile this paradigm with existing physical frameworks by considering the superposition of different populations of damaged contacts.

Longevity of coal waste for controlling cadmium-contaminated groundwater considering groundwater velocity.

Coal waste composed of naturally occurring minerals is applicable as a reactive medium to permeable reactive barriers due to its reactivity to heavy metals. In this study, we evaluated the longevity of coal waste as PRB media to control heavy metal-contaminated groundwater considering variable groundwater velocity. Breakthrough experiments were conducted using coal waste-filled column by injecting artificial groundwater, 10mg/L of cadmium solution. The artificial groundwater was fed to the column at different flow rates to mimic a wide range of porewater velocities in the saturated zone. The reaction between cadmium breakthrough curves was analyzed using a two-site nonequilibrium sorption model. The cadmium breakthrough curves showed a significant retardation, which increased with decreasing porewater velocity. The greater the retardation, the longer the longevity of coal waste could be expected. The greater retardation under a slower velocity environment was due to the higher fraction of equilibrium reaction. The nonequilibrium reaction parameters could be functionalized with respect to the porewater velocity. The simulation of contaminant transport using the reaction parameters could be used as a method to evaluate the longevity of the pollution-blocking material in an underground environment.

Alignment of excess deformations of buildings using the Geocomposite method

One of the problems arising in the buildings in operation is the manifestation of excessive deformations, which leads to an emergency condition of the structure. It often occurs because of the heterogeneity of the construction site, the presence of weak soils in the base of the building and the presence of a variable groundwater level. We have proposed the Geocomposite method to compensate excessive subsidence by the example of an emergency building. In the article the calculations are made and the technology of application of this method is described.

Quantitative Characteristics of Groundwater and its Distribution in Tal-Afar Region- Iraq

The current research aims to know the quantitative characteristics of groundwater and its spatial distribution in Tal Afar district. It was relied on a set of data related to groundwater. All of them were entered into the GIS environment for the purpose of performing digital manipulations and drawing out maps. It was found that the depth of the groundwater ranges between (0-519) m, the stable groundwater level is within (0-89) m, and the variable groundwater level is (0-165) m. And the amount of decrease in the wells was within (0-146.4) m, and the productivity of these wells ranged between (37.28-0) L/sec, and the amount of conductivity was between (1345-0) m2 / day, and the productivity of water springs spread in the study area It was within (0-1000) L / sec. The study showed that the distribution and direction of the wells are from the northwest to the southeast of the study area and its standard distance covered 61.5% of the wells data, and the direction of the wells distribution was 120º towards the north in an oval shape that included approximately 66.76% of the data entered wells.