Groundwater Flow Direction Research Articles

Irrigation-Intensive Groundwater Modeling of Complex Aquifer Systems Through Integration of Big Geological Data

This study identifies hydrogeologic characteristics of complex aquifers based on constructing stratigraphic structure with large, non-uniform well log data. The approach was validated through a modeling study of the irrigation-intensive Chicot aquifer system, which is an important Pleistocene-Holocene aquifer of the Coastal Lowlands aquifer system in the southwestern Louisiana. Various well log types were unified into the same data structure, prioritized based on data sources, and interpolated to generate a detailed stratigraphic structure. More than 29,000 well logs were integrated to construct a stratigraphy model of 56 model layers for the Chicot aquifer system. The stratigraphy model revealed interconnections of various sands in the system, where 90% of the model domain is covered by fine-grained sediments. Although the groundwater model estimated a slight groundwater storage gain during 2005–2014 for the entire region, groundwater storage in the agricultural area was depleted. Nevertheless, the quick groundwater storage recovery during the non-irrigation seasons suggests that the Chicot aquifer system is a prolific aquifer system. The groundwater modeling result shows that the gulfward groundwater flow direction prior to pumping has been reversed toward inland pumping areas. The large upward vertical flow from the deeper sands indicates potential saltwater migration from the base of the Chicot aquifer system.

Impact of geology and anthropogenic activities over the water quality with emphasis on fluoride in water scarce Lalitpur district of Bundelkhand region, India

The Bundelkhand region of India is suffering from acute water scarcity, raising concern over the potability in the region. Therefore, to develop a baseline data set of groundwater quality, sampling was carried out from the 110 existing shallow hand pumps and tube wells covering the Lalitpur district. Groundwater samples were investigated for hydro-geochemical and isotopic signatures (δ18O and δ2H) to understand the driving factors leading to water quality and its contamination in the region. The results of Hierarchical cluster analysis revealed four different clusters according to their water quality. Cluster 1 and 2 water samples have a good quality of water and these samples fall in the vicinity of major or minor drainage networks of the area. Whereas, clusters 3 and 4 are of deteriorated water quality and located far-off from the drainage networks in the study area. The findings from chemical analysis and chemometric method suggest that the groundwater composition is mainly influenced by rock weathering and anthropogenic activities. Fluoride exposure dosage for the infant and children is twice that of adults in the study area, indicating a stronger impact of fluoride concentration in infants and children. The stable isotopic analysis shows that origin of groundwater is local precipitation, with evaporative enrichment in groundwater. The groundwater of cluster 3 and 4 shows evaporative nature along with high EC and Cl concentration. The variation of concentration of ions in the study area prevails along the groundwater flow direction and surface drainage reveals the control of hydrogeological attributes in the groundwater.

Alluvial Terraces and Contaminant Sources of the Santa Catarina River in the Monterrey Metropolitan Area, Mexico

ABSTRACT The development of the Monterrey Metropolitan Area (MMA) and human carelessness have severely altered the Santa Catarina River (SCR). The objective of this research was to integrate fieldwork, a digital elevation model, exploratory surveys and satellite images analysis to develop a GIS-based map scale 1:40,000 and 1:5,000 of the Quaternary alluvial terraces and Cretaceous geologic formations present in the SCR. In addition, this study presents river geologic cross-sections, hydraulic conductivity estimates per terrace, a piezometric chart (dry season), and a database of contaminant sources along the river. The main results were the following: three terraces levels were identified, the distribution and hydrogeological properties of the terraces were documented, groundwater flow direction was southwest (SW) to northeast (NE), and 154 contaminant sources were georeferenced. This investigation lays down the basis for future environmental assessments and studies related to the quality and water supply for the MMA.

Feasibility Analysis of Freezing Method in Strong Permeability Strata

If the underground engineering meets the strong permeable strata, such as sand and pebble strata, it will face huge challenges. Effective sealing of water has become a prerequisite for determining the safety of the project. Freezing method is currently an effective method for dealing with complex permeable strata, however, the influence of the groundwater velocity on the freezing engineering is huge. If the groundwater flow rate is too high, the freezing cannot be completed normally. Therefore, for the freezing project of strong permeable formation, the speed and flow direction of groundwater is a focus of our research. The connecting channel at the bottom of the river of Fuzhou Metro is planned to be constructed by freezing method. The main soil layers are the strong permeable strata represented by the coarse medium sand layer and the pebble layer. Therefore, the measurement of the velocity and direction of the groundwater at the bottom of the river was carried out, and the influence of the groundwater on the freezing project was judged based on the measurement results. If the groundwater velocity is too high, normal freezing cannot be achieved. Referring to the form of the cofferdam, a composite reinforcement method is proposed.

Assessment of declining groundwater levels due to excessive pumping in the Dhaka District of Bangladesh

Hydrogeologically, the aquifers of the Dhaka district are located in the B, H and J zones of a total of 15 BWDB-UNDP (1982) groundwater development zones and were considered to have a high groundwater potential. Unplanned and excess groundwater extraction is causing a decline of groundwater potentiometric heads in the area. Groundwater level data from nineteen (19) years of the two aquifers of the Dhaka district have been analyzed to observe how the patterns of water level changes vary throughout the area. The Mann–Kendal (M–K) test with Theil-slope Sen's slope exhibits three categories of groundwater level changes. In densely populated city areas, the trend is extremely negative, with steep declines and annual changing rates that range from − 1.5 m/year to − 2.11 m/year; − 1.01 m/year to − 1.09 m/year in newly urbanized areas; and that range from 0.01 m/year to − 0.36 m/year in the rural areas. The pattern of changing decline trends was observed through six (6) year interval contour maps from 2000 to 2018, and three groundwater zones have been described in the district on the basis of water level changes. This assessment indicated that the dominant groundwater flow direction in the area is in an easterly direction towards urban areas, and that significant groundwater declines are occurring even on the peripheries of the city area. Probable causes of groundwater depletion and approaches to mitigate this issue have been discussed on the basis of geological and hydrogeological studies and investigations in the area.

Groundwater Quality Study Based on the Existence of Escherichia coli as Bioindicator

The research aim was to observe the distribution pattern of Escherichia coli as groundwater pollution indicator in the most populous area, Matraman Sub-District Area in Jakarta, Indonesia (106°49’35” EL and 06°10’37” SL) consists of six (6) Urban Villages. The existence of Escherichia coli was measured with Most Probable Number (MPN) method as mentioned in Indonesian Standard Number 01-2332.1-2006. This research was also measure pollution parameter of Dissolved Oxygen (DO) and pH, and topography analyses used as well to determine groundwater flow direction. Groundwater sampling was conducted in several housings that have low, middle, and high income as indicator of sanitation quality which causes groundwater pollution by Escherichia coli bacteria. The research result showed that the level of average Escherichia coli was 345,9778, 310,0556, and 727,1389 MPN/100 mL. Escherichia coli distribution pattern was headed from southeastern to northwestern area, in correspondence with Matraman Sub-District topography. The average pH level, temperature and DO0 in whole area respectively were 6.3, 24.7°C and 2.238 mg/L, that exceeded minimum water quality standards in Indonesian Minister of Health Regulation Number 492/MENKES/PER/IV/2010 regarding drinking water quality requirements. This study could be a reference for daily groundwater utilization in Matraman Sub-District and to provide information for further research.

Investigating groundwater: Middle school students’ mapping data-driven, computer-based models to socio-hydrologic phenomena

Groundwater is a critical component of the global water cycle and standards-based topic within science education. However, students articulate an array of ideas about groundwater systems, including their natural and human elements. One way to support students’ learning about groundwater systems is through the use of data-driven, computer-based modeling tools in technology-enabled science learning environments. To use models to reason productively about groundwater, students must be able to interpret the relationship between the model and the phenomena it represents. Here, we report findings from a study conducted in 7th-grade classrooms (n = 209) during implementation of a 3-week curriculum module designed around a data-driven, computer-based groundwater modeling tool – the Hydrogeology Challenge. Students completed a series of tasks using the model to reason about and engage in problem-solving about a real-world, scenario-based water challenge. Here, we focus on how students relate – or map – elements of the model to the components of the authentic water-related phenomena they represent. We conducted quantitative and qualitative analyses of student artifacts and interviews. Findings suggest that students could more easily interpret and understand model elements which represent human dimensions of groundwater systems, such as wells, than they could elements that represent natural dimensions and processes, such as contour lines or groundwater flow direction. These findings provide important insights into students’ model-based reasoning about groundwater and teaching and learning about coupled human-hydrological systems.

Measuring a Low Horizontal Hydraulic Gradient in a High Transmissivity Aquifer.

High transmissivity aquifers typically have low hydraulic gradients (i.e., a flat water table). Measuring low gradients using water levels can be problematic because measurement error may be greater than the true difference in water levels (i.e., a low signal-to-noise ratio). In this study, the feasibility of measuring a hydraulic gradient in the range of 10-6 to 10-5 m/m was demonstrated. The study was performed at a site where the depth to water from land surface ranged from 40.1 to 94.2m and the aquifer transmissivity was estimated at 41,300 m2 /d (hydraulic conductivity of 18,800 m/d). The goals of the study were to reduce measurement error as much as practicable and assess the importance of factors affecting water level measurement accuracy. Well verticality was the largest source of error (0.000 to 0.168 m; median of 0.014 m), and geodetic survey of casing elevations was the next most important source of error (0.002 to 0.013 m; median of 0.005 m). Variability due to barometric pressure fluctuations was not an important factor at the site. Hydraulic heads were measured to an accuracy of ±0.0065 m, and the average hydraulic gradient was estimated to be 8.0 × 10-6 (±0.9 × 10-6 )m/m. The improvement in accuracy allowed for two reversals in the groundwater flow direction to be identified, after which the gradient averaged 2.5 × 10-5 (±0.4 × 10-5 )m/m. This study showed it is possible to sufficiently control sources of error to measure hydraulic gradients in the 10-6 to 10-5 m/m range.

Assessment of river water\u2013groundwater\u2013seawater interactions in the coastal delta of Bangladesh based on hydrochemistry and salinity distribution

A synchronization study among hydrochemistry, hydrochemical facies evaluation, EC observation, salinity distribution and groundwater flow direction has been addressed to assess river water–groundwater–seawater interactions in the coastal delta of southern Bangladesh. The findings show that river water, shallow groundwater and deep groundwater interact with seawater at various intensities within the complex dynamics of hydrochemical facies evaluation. Deep groundwater is intensively influenced by seawater, where shallow groundwater is moderately affected and river water is very negligibly affected. Major cation and anion have been plotted in the Piper diagrams and hydrochemical facies diagrams (HFE-D) to clarify the result. More than 60% of the water samples of the river lie on the Ca-HCO3 (or Mg-HCO3) facies quadrant, and more than 70% of the shallow groundwater samples and more than 95% of the deep groundwater samples lie on the Na-Cl facies quadrant of the HFE-D diagram. River water types are dissimilar, and approximately 82% of facies are characterized by freshening phases and 18% by intrusion phases. Mixed water types with predominate of Na-Cl were observed in shallow groundwater where the hydrochemical facies are characterized by 53 percent freshening phases and 47 percent intrusion phases. Deep groundwater hydrochemistry clearly indicates the dominant Na-Cl type of water in the study area where only four hydrochemical facies are observed and 78 percent correspond to the intrusion phases and 22 percent to the freshening phases. Both direct and reverse cation exchange reactions take place in shallow groundwater, where deep groundwater is predominantly characterized by reverse cation exchange reactions. Two end members: seawater of Bay of Bengal and freshwater, contribute to the exchange reactions in the coastal aquifer of the study area. In terms of nitrate contamination, river waters are affected by negligible to low concentrations, shallow groundwater is affected by moderate to high concentrations and deep groundwater is affected by moderate to very high nitrate concentrations. Dissimilarity in electrical conductivity (EC) values, variation of salinity distribution maps and groundwater flow direction suggest the possible interconnections among river water, groundwater and aquifer sediments. Significant concentrations of Na+ and Cl− ions lead to seawater contamination in groundwater, and HCO3− along with Na+, Ca2+, Mg2+ in river water suggests mixing of freshwater and seawater, which could have adverse effects both in coastal delta aquatic life and in agriculture.

Sources and hydrogeological conditions that cause high iodine concentrations in deep groundwater in the Zhangwei watershed, North China Plain

The sources and primary mechanisms of high iodine concentration in deep groundwater are rarely reported, thereby restricting the development and utilization of the related groundwater resources. To address these issues, 194 deep groundwater samples were collected from the Zhangwei watershed in the North China Plain, China, to analyze their constituents including iodine. Statistics, principal component analysis and hydrological methods were employed to determine the distribution of iodine concentrations and their controlling hydrogeochemical processes. The results show that the iodine concentration ranged from 2 to 446 μg/L and generally increased along the groundwater flow direction. Three zones with high iodine concentration (> 20 μg/L) were delineated as the alluvial–proluvial plain (Zone A, average 70 μg/L), alluvial–lake plain (Zone B, average 83 μg/L) and coastal plain (Zone C, average 199 μg/L), respectively. In Zone A, aquifer minerals weathering probably releases iodate ions into groundwater. The iodate is reduced with nitrate as the electron acceptor of iodine and transported with the precipitation infiltrating through the vadose zone to recharge groundwater, resulting in increasing the groundwater iodine concentration. In Zone B, the iodine concentrations depend on the contents of the organic matter, clay minerals, and iron aluminum oxide in the alluvial–lake sediments, due to that the deeply buried organic matter is rich in iodine which is released into groundwater through the biodegradation of organic matter, In Zone C, the iodine is probably derived from the sediments which were deposited in Quaternary marine transgression events, and its enrichment was controlled by the strong reduction condition of the deep aquifers. In one word, the iodine sources and hydrogeological conditions determined the high iodine concentrations of deep groundwater in the studied watershed. These findings can provide foundation for further insight into the high iodine concentration of deep groundwater in other hydrogeological units of the North China Plain and other similar units over the world, thereby ensuring drinking groundwater safety.

Analytical model for arbitrarily configured neighboring shallow geothermal installations in the presence of groundwater flow

This paper introduces an analytical model analyzing the effect of groundwater flow on heat transfer in an infinite conductive-convective porous domain representing shallow geothermal systems with arbitrarily configured cylindrical heat sources. The model is formulated based on the moving source concept and solved based on the spectral analysis method and the superposition principle. Compared to models based on the Green’s function and the Laplace transform, the proposed spectral model has a simpler formulation, computationally efficient and easy to implement in computer codes. It can handle random time-dependent thermal loads and any arbitrarily configured grid distribution. The verification and numerical examples demonstrate the computational capabilities of the model, and show how the groundwater flow can play an important role in the thermal interaction between heat sources. They also feature how to make use of the direction of groundwater flow to avoid undesirable thermal interaction between neighboring installations, rapid depletion of energy sources and unfair mining of geothermal energy.

Active saltwater intrusion of shrinking Bakhtegan -Thask Lakes in South Iran threatens the freshwater resources of coastal aquifers

Study regionEight Coastal aquifers (CA) of Bakhtegan and Tashk lakes (BTL) and salt marsh, southern Iran Study focusBTL, Wetlands of International Importance, have been shrinking due to reduction in surface discharge, groundwater overexploitation, and drought. We show that this resulted in an increase of BTL total dissolved solids (TDS) from 45400 to 256000 mg/l. To characterize the hydrogeological behavior of the coastal aquifers after shrinkage, major ions, TDS and water level were measured along a transect from inside the BL to one of the aquifers. The spatial distribution of electrical conductivity (EC), discharge and iso-potential maps was determined. A support vector regression technique was used to forecast EC and water level in CA for the next decade. New hydrological insights for the regionFive zones based on EC changes and hydraulic gradient are recognized, namely: brine, highly saline, brackish, transition, and freshwater. The groundwater flow direction is from both the BTL and Fresh Water Zone, converging towards the intermediately positioned Transition Zone. Saltwater intrusion is active based on the hydraulic gradient towards the land and the gradient of water density. A schematic flow model of CA was proposed based on active SWI, groundwater flow direction, and chemical signature. Forecasting reveals a significant further deterioration of water quality and drop in groundwater levels, which emphasizes the need for systematic and sustainable water management.

Geochemical and microbial characteristics of seepage water and mineral precipitates in a radwaste disposal facility impacted by seawater intrusion and high alkalinity

The construction of an underground facility can dramatically change the quality, flow direction, and level of groundwater. It may also impact subsurface microbial composition and activity. Groundwater quality was monitored over eight years in two observational wells near an underground disposal facility on the east coast of South Korea. The results showed dramatic increases in dissolved ions such as O2, Na, Ca, Mg, and SO4 during facility construction. Seepage water samples downgradient from the silos and tunnels, and precipitates deposited along the seepage water flow path were collected to determine the impact inside the disposal facility. X-ray analysis (powder X-ray diffraction (pXRD) and X-ray absorption fine structure (XAFS)) were used to characterize the mineral precipitates. Microbial community composition was determined by 16S rRNA gene sequencing. The seepage water composition was of two types: Ca–Cl and Ca–Na–HCO3. The ratio of Cl and δ18O showed that the Ca–Cl type seepage water was influenced by groundwater mixed with seawater ranging from 2.7% to 15.1%. Various sulfate-reducing bacteria were identified in the Ca–Cl type seepage water, exhibiting relatively high sulfate content from seawater intrusion. Samples from the Ca–Na–HCO3 type seepage water had an extremely high pH (>10) and abundance of Hydrogenophaga. The precipitates observed along the flow path of the seepage water included calcite, ferrihydrite, green rust, and siderite, depending on seepage water chemistry and microbial activity. This study suggests that the construction of underground structures creates distinct, localized geochemical conditions (e.g., high alkalinity, high salinity, and oxic conditions), which may impact microbial communities. These biogeochemical changes may have undesirable large-scale impacts such as water pump clogging. An understanding of the process and long-term monitoring are essential to assess the safety of underground facilities.

Hydrogeophysical appraisal of groundwater potential in the fractured basement aquifer of the federal capital territory, Abuja, Nigeria

In this study, eighteen (18) vertical electrical sounding (VES) data points were located in the Federal Capital Territory (FCT), Abuja, Nigeria with ABEM Terrameter using Schlumberger array to delineate potential groundwater development areas. Groundwater flow direction map was produced using the elevation of the water level from sea level with GIS Arc/Info Point coverage. The investigated areas have four geoelectric sections, categorized as topsoil, clay, fractured/weathered basement, and fresh basement. The groundwater is mainly confined in the fractured/weathered basement. It generally flows from NW to SE, but this flow is not steady. It has been obstructed and reoriented towards the south, whereas some portion flows towards the northern parts of the aquifer system peradventure due to the variation in aquifer depth from place to place. Out of the 18 VES points, 9 points located around the NE and SE peripherals of the study area have groundwater development potentials at depths ranging from 40 - 80 m and aquifer thickness of 25 – 65 m, characterized by resistivity values that varied from 80 – 680 Ωm, whilst the other nine in the SW and central parts do not show promising groundwater development potentials because they lack fractured/weathered zones. The northern and SE zones, which comprise areas such as Bwari, Kuje, Idu CITEC, Sherete, and GTSSC are the preferred targets for water well drilling than the southern zone. However, other communities including Gwagwalada and Gugugu in the southern zone also offer promising groundwater potentials.

Water table dynamics beneath onsite wastewater systems in eastern North Carolina in response to Hurricane Florence

AbstractOnsite wastewater treatment systems (OWTSs) are commonly used in eastern North Carolina. A vadose zone or vertical separation distance (VSD) between the OWTS drainfield trenches and groundwater is required for effective aerobic wastewater treatment. Extreme weather events, including hurricanes, can deliver significant rainfall that influences groundwater levels and reduces the VSD, thus also influencing the treatment of wastewater by the OWTS. Few studies have quantified the effects of storms on the VSD. Groundwater levels at three sites with the OWTS were monitored before, during, and after Hurricane Florence. Groundwater rose over 1.5 m within 9 h at the sites in response to rain from the hurricane but took more than 3.5 weeks to return to prestorm levels. Groundwater inundated the drainfield trenches for several days at two sites leading to direct discharge of wastewater to groundwater. The hydraulic gradient and the groundwater velocity increased during the storm and the groundwater flow direction shifted, leading to greater dispersion of wastewater impacted groundwater. The wastewater treatment efficiency of the soil-based OWTS in coastal areas may lessen over time because of rising water tables and reduced VSD. Individual pretreatment OWTSs, elevated drainfields, or centralized sewage treatment may be required in regions with shrinking VSDs.

WITHDRAWN: Application of GIS software in analyzing hydrodynamics of sub surface water demeanor zones in Gondwana sedimentary terrain of eastern India

Abstract Gondwana study terrain of Orissa, India has diverse geological, geophysical, hydrological, hydrogeological and meteorological information which have been integrated for extensive study. The study aims at acknowledging the geology and hydrogeology of the region backing up with the type and existence of aquifers around the region. To get the detailed features 225 observation wells, 40 National Hydrograph Network Stations (NHNS), 40 groundwater monitoring (GWM) stations and 83 exploratory wells were collected from different sources to analyse the groundwater occurrence in the study area. The data obtained were integrated and initiated for lithological distribution, groundwater flow directions, depth to water levels in pre- and post-monsoon. Limited aquifer thickness of unconfined aquifer and poor yield from deeper aquifers has been studied intricately. Groundwater occurrence has provided a paradigm to in-depth study in association with detailed lateral and vertical demarcation and behaviour of aquifers. Taking into consideration about lithology, the area can be hydrogeologically divided into consolidated, semiconsolidated and unconsolidated zones. The semi and unconsolidated zones are the groundwater potential zones where the aquifer remains under saturated condition. Though semiconsolidated zones bear abundant volume of water but hydrological parameters illustrate that they do have the potentiality for shallow water wells whereas the fissured and fractured zones in consolidated formations yield perennial source of groundwater illustrating deep borings.

Elemental composition of biogenic sediments reveals palaeoclimatic changes during the Late Weichselian in a Central European river valley: A statistical approach

Five sections of sediment from mire infillings located in different part of the catchment small river valley in central Europe were studied by lithological and geochemical analysis in order to examine the response of aquatic ecosystems to the environment changes during Late Weischselian (LW). Differentiation of geochemical composition and grain-size properties in biogenic deposits is being considered as a result of change hydroclimatic conditions and geology structure in individual parts of the catchment. The principal component analysis (PCA) and clustered by hierarchical method (HCA) were chosen to create the lithogeochemical facies and their chronostratigraphy variability. Biogenic sediments of the studied river mires, regardless of the location in a given reach of the valley, are represents mainly by mineral or organic-mineral lithogeochemial facies with increased of lithophilic elements (Na, K and Mg). Similar chemical composition of gyttja and peat sediments in almost all periods of LW, indicate the strongly mechanical denudation processes in the Grabia River valley. The major process, conditioning the development of the mires (in it type and rate sedimentation), was the variable terrigenous material input which are related to its variable dynamic of floods. The higher than expected chemical denudation probably a result of specific groundwater flow direction and dissolving vari-grained sands and silts, which build plains in the central part of the study catchment. The number and thickness of individual lithogeochemical facies are caused by differences in the potential volume of the hydrologically active zone and geological conditions of the emerge or disappear permafrost.

Geostatistical based framework for spatial modeling of groundwater level during dry and wet seasons in an arid region: a case study at Hadat Ash-Sham experimental station, Saudi Arabia

Saudi Arabia (SA) lies in an arid region where groundwater is the main natural resource; therefore, it is essential to understand the groundwater dynamics for the best groundwater management practice in SA. In Hadat Ash-Sham Farm Experimental Station, SA, water table data from 11 wells and rainfall data were monitored for 16 months. The water table (WT) data is analyzed using the geostatistical method with the ordinary Kriging technique to generate the best WT spatial distribution map for each month and the expected flow direction. The cross-validation technique is used to evaluate the goodness of the developed WT maps. The Kriging maps show two regimes: weak spatial dependence (WSD, the ratio of the nugget to sill > 75%) and strong spatial dependence (SSD, the ratio of the nugget to sill < 25%). The WSD regime happens during dry seasons, while the SSD happens during wet seasons. The SSD gives better results and accuracy when compared to WSD. The root-mean-square error (RMSE) of WT varies between 0.26 and 3.4 m in the case of SSD, while it varies between 0.51 and 4.8 m in the case of WSD. WT maps show that the groundwater flow direction is from south-east to north-west during the wet season (SSD). This direction is in the orientation of surface stream with higher elevation (in the south) to the surface stream with lower elevation (in the north), where the study area is between these surface streams. While during the dry season (WSD), there is no preferred direction since there is almost no flow.

Municipal waste landfill as a source of polychlorinated biphenyls releases to the environment.

This study aimed to investigate the impact of municipal waste landfill on polychlorinated biphenyls (PCBs) release to the environment concerning groundwater flow directions. The contents of polychlorinated biphenyls in soils, plants and water were analysed at various distances from the landfill. Thanks to low solubility PCBs in water groundwater flow direction, under the landfill, have an influence on PCBs concentration in groundwater. Strong PCBs’ sorption to organic matter caused that no affect groundwater flow directions on PCB content in soils and plants’ tissues was observed. The largest PCBs deposition zone was located 50 m from the contamination source (landfill). Tri-CB and tetra-CB homologues were capable of migration deep into the soil profile, which could be related to the geological material from which the soils under study were developed, as well as to the properties of the PCB homologues.

Determination of groundwater potential zones using Geographical Information Systems (GIS) and Analytic Hierarchy Process (AHP) between Edirne-Kalkansogut (northwestern Turkey)

Groundwater is one of the most important resources when it comes to satisfying the freshwater needs of a region. In recent years, due to the growing climate change threat to water supplies, the importance of groundwater resources has increased. The main aim of this study is to determine groundwater potential zones using Geographical Information Systems (GIS) and Analytic Hierarchy Process (AHP) techniques in the area of Edirne-Kalkansogut, Northwestern Turkey. Several environmental parameters (lithology, fault density, geomorphology, soil, land use and land cover, drainage density, lineament density, precipitation, and slope) were analyzed to determine groundwater potential zones. The weighting of the parameters was conducted using the AHP technique, overlay analysis was carried out on the GIS platform. According to obtained results; 14% of the study area exhibits poor groundwater potential and 47% of the study area has moderate groundwater potential. Good groundwater potential zones and very good groundwater potential zones constitute 31% and 8% of the study area respectively. The groundwater potential increasing gradually from the northeast to southwest. Tundzha Rivers' alluvial flood plain shows very good groundwater potential and most of The Strandzha Massif have poor to moderate groundwater potential. Examination of groundwater characteristics such as groundwater levels, groundwater flow directions, springs and wells' distribution characteristics, and well discharge data verified the results. Findings have great potential to increase the success of water management policies, efficient use of natural resources, physical planning, and sustainable groundwater development between Edirne-Kalkansogut, especially in the brink of climate changes’ unfavorable threats to human life. The methods of this study can be applied anywhere else in the world. The results of this study have applications to the further studies dealing with sustainable groundwater, basin management, agriculture, and climate change-groundwater relationship.