Constructed wetlands (CWs) are artificial systems used for wastewater treatment, whose objective is to reproduce, under controlled conditions, the treatment mechanisms that occur in natural environments, through the exploration and improve the processes that involve the vegetation, porous media and microbial assemblages. Horizontal subsurface flow constructed wetlands (HSSF-CWs) is characterized by flow in a horizontal direction, in a gravel or sand beds planted or unplanted with emergent macrophytes whose the inlet and outlet are horizontally opposed, which allows the wastewater flow through the rhizosphere and have contact with the biofilm formed in subsurface. Traditional studies about CWs focuses on the efficiency of contaminants removal look at systems as a "black-boxes" from empirical approaches and do not distinguish between the different active removals processes. The development of numerical models, in order to helping to identify and improve the role of each element acting in the treatment, whether the properties of the porous media, constructive geometry, flow characteristics, among others, appears as an alternative to reach a more detailed understanding of the internal processes involved in CWs. In general, numerical models consist of governing equations (derived from the mathematical combination of the water balance and Darcy's law), initial conditions (they refer to the distribution of the hydraulic head in the model domain) and boundaries conditions (define the hydraulic or physical boundaries that delimit the model domain). In the last decade, different 1D and 2D numerical models have been developed and applied for the simulation of subsurface flow CWs under conditions of saturated horizontal flow (CWM1-RETRASO and PHWAT), variably saturated vertical flow (FITOVERT and HYDRUS-CW2D) and vertical or horizontally saturated flow (HYDRUS-CWM1). However, few studies regarding the application of 3D numerical models for CWs simulation are reported in the scientific literature. In this study, the hydrodynamic simulation of the porous media in a horizontal subsurface flow constructed wetland was run through the application of a 3D numerical model. The flow patterns were simulated according to the project design and scenarios with changes in the porous media hydrodynamic (hydraulic conductivity) and in the positioning of the wastewater distribution mechanisms (distribution along the cross section with two pipes) in order to verify the influence of these factors in the flow pattern and also to indicate advantages and disadvantages that contribute to the design. The softwares MODFLOW and MODPATH, in the GMS family code, were used for to simulate the direction and flow velocity, hydraulic head and pathlines. The model proved to be a powerful tool to simulation, allowing observing the interdependence between the hydrodynamic parameters and the hydraulic characteristics in the porous media. The simulated scenarios showed the possibility of improving the flow patterns, mainly using two pipes to distribute the wastewater in a more homogeneous way along the cross section of the bed. The use of a porous media with lower hydraulic conductivity also showed improvement in flow characteristics evaluated. However, the general context of wastewater treatment facilities (pretreatment units and tributary loads) should be considered, since materials with low hydraulic conductivity are more susceptible to clogging. Proper design is crucial to improving the treatment conditions in the HSSF-CWs and also to avoid the occurrence of hydraulic problems and damage to the treatment, such as the clogging. / Wetlands construídos (WCs) são tecnologias empregadas para o tratamento de águas residuárias, cujo objetivo é reproduzir, sob condições controladas, os mecanismos de depuração que ocorrem em meios naturais, através da exploração e aperfeiçoamento dos processos que envolvem a vegetação, o substrato e os microrganismos. Wetlands construídos de escoamento subsuperficial de fluxo horizontal (WCFH) são caracterizados pelo fluxo em direção horizontal através de um leito de cascalho ou areia, vegetado ou não com macrófitas emergentes, cujas entrada e saída dos efluentes são horizontalmente opostas, o que permite que as águas residuárias fluam através da rizosfera e tenham contato com o biofilme formado em subsuperfície. Tradicionalmente, os estudos sobre WCs incidem apenas sobre a remoção das concentrações de contaminantes, considerando esses sistemas como “black-boxes” a partir de abordagens empíricas, sem fazer distinção entre os diferentes processos atuantes. O desenvolvimento de modelos numéricos, como forma de auxiliar a identificar e aperfeiçoar o papel de cada elemento atuante no tratamento, quer sejam as propriedades do meio poroso, a geometria construtiva, as características de fluxo, entre outros, surge como alternativa para o alcance de uma compreensão mais detalhada dos processos internos intervenientes nos WCs. De uma forma geral, os modelos numéricos são constituídos por equações governantes (derivada da combinação matemática da equação de balanço de água e da lei de Darcy), por condições iniciais (dizem respeito à distribuição da carga hidráulica no domínio do modelo) e por condições de contorno (definem as fronteiras hidráulicas ou físicas que delimitam o domínio do modelo). Na última década, diferentes modelos 1D e 2D foram desenvolvidos e aplicados para a simulação de WCs de escoamento subsuperficial em condições de fluxo horizontal saturado (CWM1-RETRASO e PHWAT), vertical variavelmente saturado (FITOVERT e HYDRUS-CW2D) e vertical ou horizontal variavelmente saturado (HYDRUS-CWM1). Porém, poucas experiências relativas à aplicação de modelos 3D para simulação de WCs são relatadas pela literatura científica. Neste trabalho, a simulação da hidrodinâmica do meio poroso de um sistema de tratamento de efluentes do tipo wetlands construídos de escoamento subsuperficial de fluxo horizontal foi realizada por meio da aplicação de um modelo numérico 3D. Foram simuladas as condições de fluxo conforme as especificações de um projeto de engenheria, e também cenários com mudanças nas características hidrodinâmicas do meio poroso (condutividade hidráulica) e no posicionamento dos mecanismos de distribuição das águas residuárias (distribuição ao longo da seção transversal por meio de duas tubulações) visando verificar a influência desses fatores no sistema de fluxo e também indicar vantagens e desvantagens que contribuam para a elaboração de projetos. Os softwares MODFLOW e MODPATH, executados por meio da interface GMS, foram utilizados para a simulação da direção e velocidade de fluxo, nível hidráulico e linhas de trajetória das partículas transportadas por advecção. O modelo provou ser uma ferramenta poderosa para a simulação, permitindo visualizar a interdependência entre os parâmetros hidrodinâmicos e as características hidráulicas do meio poroso. Os cenários simulados mostraram a possibilidade de melhoria dos padrões de fluxo, principalmente por meio do uso de duas tubulações para distribuição dos efluentes de forma mais homogênea ao longo da seção transversal do leito. O uso de materiais com menor condutividade hidráulica também apresentou melhoria nas características de fluxo avaliadas. Porém, deve-se considerar o contexto geral das instalações de tratamento das águas residuárias (unidades de tratamento preliminar e cargas afluentes), visto que materiais com baixa condutividade hidráulica são mais susceptíveis ao entupimento. A concepção adequada é crucial para melhorar as condições de tratamento verificadas nos WCFH e também para evitar a ocorrência de danos e problemas hidráulicos, como a estagnação de fluxo em zonas de baixa velocidade de escoamento.

För att uppskatta inläckage till en bergförlagd tunnel finns ett antal analytiska modeller som tar hänsyn till parametrar som hydraulisk konduktivitet, storlek på tunnel och hur djupt tunneln är förlagd. Ett antagande i samtliga analytiska modeller är en homogen och isotrop geologi. I verkligheten är detta sällan fallet, som i exempelvis Kista, strax norr om Stockholm, där en VA-tunnel har drivits under 2017 och inläckaget till tunneln överskrider kravet som baserats på en analytisk modell. En modell utvecklas över områdets geologi och grundvattenmagasin för att simulera grundvattennivåer med och utan inläckage till en bergförlagd tunnel. Avsänkningens utbredning till följd av tunneln är ett s.k. influensområde. Modellen utvecklas i ett relativt nytt modelleringsverktyg, MODFLOW-USG, som utnyttjar ostrukturerade rasternät för att bättre representera tunnelsträckning och öka numerisk stabilitet. Geologin modelleras utifrån jorddjup, bergöveryta och geotekniska undersökningar som utförts i området. Hydraulisk konduktivitet i berget approximeras med hjälp av SGU:s brunnsarkiv. Dessutom utvecklas en modell som innehåller en anslutande tunnel och två st sprickzoner i berget. Jämfört med det influensområde som skattats i tunnelns MKB visar modellen på ett mindre influensområde i vissa riktningar och ett större i andra riktningar. Resultaten bekräftar att influensområdet ökar med ett ökat inläckage, och att en numerisk modell är bättre på att representera områdesspecifik geologi än en enkel vattenbalansmodell. Influensområdet i det undre magasinet i Kista bedöms vara cirka 24,4 ha stort. Enligt den numeriska modellen ger en förändring i inläckage på 0,01 l/min och m tunnel en ökning respektive miskning av influensområdet med cirka 19 %. Vidare visar arbetet på att val av analytisk modell för att skatta inläckage kan påverka skattning med en faktor 3. För att hantera osäkerheter i skattning av inläckage föreslås att flera olika värden på inläckage simuleras för att bedöma influensområdets utbredning och för att skapa en uppfattning om hur storleken på inläckaget påverkar influensområdets utbredning. / To determine leakage into rock tunnels one can choose between a range of analytical models. Common to all analytical models is their inability to reflect complex hydrogeological settings and only taking into account hydraulic conductivity, dimensions of the tunnel and tunnel depth. In Stockholm, Sweden, a rock tunnel built in 2017 currently exceeds maximum allowed leakage which was derived from an analytical model. A model is developed to represent the site’s hydrogeological settings. The model is used to simulate groundwater levels with and without representation of the tunnel, the area of influence being the difference between the two. A Voronoi-cell unstructured grid is implemented in MODFLOW-USG to improve representation of complex geology and increase numerical stability. Geology is modeled using soil depth, bed rock surface and geotechnical investigations. Rock hydraulic conductivity is derived from a well archive. A second model is developed to represent geological fault zones and a connecting tunnel. The model verifies the positive relationship between magnitude of leakage and size of the zone of impact. Results also show an improved approximation of the zone of impact as compared to an earlier approximation derived from a simple water balance. The numerical models predicts a larger zone of impacts in some areas and a smaller zone of impact in other areas. Furthermore, the numerical model shows that a change in leakage of 0,01 l/min and m tunnel can alter the size of the zone of impact by about 19%. By comparing some of the most well-known analytical models to predict leakage it is found that the approximation can differ by a factor 3 using identical parameter values. To reflect the uncertainty in predicted leakage the author recommends simulating a numerical model with varying magnitudes of leakage. This will help in risk assessment and identify a site specific relationship between magnitude of leakage and area of influence.

Hydraulic fracturing is used to extract oil and natural gas from low permeability formations. The potential of fluids migrating from depth through adjacent wellbores and through the production wellbore was investigated using statistical modeling and predic-tive classifiers. The probability of a hydraulic fracturing well becoming hydraulically connected to an adjacent well in the Marcellus shale of New York was determined to be between 0.00% and 3.45% at the time of the study. This means that the chance of an in-duced fracture from hydraulic fracturing intersecting an existing well is highly dependent on the area of increased permeability caused by fracturing. The chance of intersecting an existing well does not mean that fluid will flow upwards; for upward migration to occur, a pathway must exist and a pressure gradient is required to drive flow, with the exception of gas flow caused by buoyancy. Predictive classifiers were employed on a dataset of wells in Alberta Canada to identify well characteristics most associated to fluid migration along the production well. The models, specifically a random forest, were able to identify pathways better than random guessing with 78% of wells in the data set identified cor-rectly. Magnetic resonance imaging (MRI) was used to visualize and quantify contami-nant transport in a soil column using a full body scanner. T1 quantification was used to determine the concentration of a contaminant surrogate in the form of Magnevist, an MRI contrast agent. Imaging showed a strong impact from density driven convection when the density difference between the two fluids was small (0.3%). MRI also identified a buildup of contrast agent concentration at the interface between a low permeability ground silica and higher permeability AFS 50-70 testing sand when density driven con-vection was eliminated.

Decision makers' conflicts about the validity of a single simulation model and inefficiencies of existing response matrix methods (RMM) hinder adopting successful groundwater management plans. We speed up the process by proposing a hybrid RMM that is most efficient for situations in which optimizable stimuli can vary through consecutive periods of uniform duration interspersed with periods of different duration. We use the hybrid RMM within Simulation-Optimization (S-O) models to develop optimal water management strategies. For the tested problems, the hybrid RMM requires as much or 63-89% less computation time than other RMMs. Second, we propose Multi-Conceptual Model Optimization (MCMO) that can help stakeholders reach a compromise strategy instead of agreeing on the validity of a single model. MCMO computes optimal strategies that simultaneously satisfy analogous constraints and bounds in multiple numerical models differing by more than parameter values. Applying MCMO to Cache Valley (Utah, USA) reveals that protecting local ecosystem limits the increased groundwater pumping to satisfy only 40% of projected water demand increase using two models. To successfully and sustainably manage Cache Valley aquifer, we evaluate sustained yield strategies (SYS) and quantify the resilience of a computed SYS. We maximize the number of new residents who can have their indoor and outdoor uses satisfied, subject to constraints on aquifer-surface waters conditions, and limiting new residents to projected increases in population (PIiP). furthermore, we examine the effect of optimization approach and sequiencing, temporally-lagged spatially distributed return flow that is a function of optimal groundwater use, and the acceptability time evaluation on the optimal yield strategy. Cache Valley aquifer can sustainably satisfy the outdoor water demand of 74%-83% and the indoor water demand of 83%-100% of the PIiP. We quantify deterministic resilience Rd(A,T,SV)=P to evaluate how completely an aquifer condition (SV) recovers after the end of climatic anomaly (A), by recovery time (T). Simulation predicts that Cache Valley aquifer system resiliences to a 2-year drought are Rd(2YD, 3 yrs, Overall) = 93% and Rd (2YD,≥8,Overall) ≥ 95%. Proportionally reducing pumping rates by 25% through the time horizon of the simulation increases the overall resilience to 96% within 3 years.

The subject of this dissertation is use of computer models as data analysis tools in several different geoscience settings, including integrated surface water/groundwater modeling, tephra fallout modeling, geophysical inversion, and hydrothermal groundwater modeling. The dissertation is organized into three chapters, which correspond to three individual publication manuscripts. In the first chapter, a linear framework is developed to identify and estimate the potential predictive consequences of using a simple computer model as a data analysis tool. The framework is applied to a complex integrated surface-water/groundwater numerical model with thousands of parameters. Several types of predictions are evaluated, including particle travel time and surface-water/groundwater exchange volume. The analysis suggests that model simplifications have the potential to corrupt many types of predictions. The implementation of the inversion, including how the objective function is formulated, what minimum of the objective function value is acceptable, and how expert knowledge is enforced on parameters, can greatly influence the manifestation of model simplification. Depending on the prediction, failure to specifically address each of these important issues during inversion is shown to degrade the reliability of some predictions. In some instances, inversion is shown to increase, rather than decrease, the uncertainty of a prediction, which defeats the purpose of using a model as a data analysis tool. In the second chapter, an efficient inversion and uncertainty quantification approach is applied to a computer model of volcanic tephra transport and deposition. The computer model simulates many physical processes related to tephra transport and fallout. The utility of the approach is demonstrated for two eruption events. In both cases, the importance of uncertainty quantification is highlighted by exposing the variability in the conditioning provided by the observations used for inversion. The worth of different types of tephra data to reduce parameter uncertainty is evaluated, as is the importance of different observation error models. The analyses reveal the importance using tephra granulometry data for inversion, which results in reduced uncertainty for most eruption parameters. In the third chapter, geophysical inversion is combined with hydrothermal modeling to evaluate the enthalpy of an undeveloped geothermal resource in a pull-apart basin located in southeastern Armenia. A high-dimensional gravity inversion is used to define the depth to the contact between the lower-density valley fill sediments and the higher-density surrounding host rock. The inverted basin depth distribution was used to define the hydrostratigraphy for the coupled groundwater-flow and heat-transport model that simulates the circulation of hydrothermal fluids in the system. Evaluation of several different geothermal system configurations indicates that the most likely system configuration is a low-enthalpy, liquid-dominated geothermal system.

The management of stormwater runoff is a particular challenge for communities in karst regions. Most guidelines for compliance with regulations for stormwater monitoring and mapping pertain to non-karst environments. It can be argued that effective stormwater management is even more essential to karst regions because stormwater receives little or no natural filtration as it is transferred through conduits in the subsurface and the buildup of pollutants underneath can be detrimental to community and environmental health if not effectively mitigated. Because of the limited resources available to determine how stormwater runoff carries potential pollutants across the surface before being transferred to the karst subsurface and then reentering back on the surface across the landscape, this study aims to use geographic information systems (GIS) to investigate this problem. The objectives of this study are twofold. The first objective is to understand the transport mechanisms for stormwater runoff and how the movement through karst systems differs from non-karst systems, especially in regards to the surface and subsurface interactions. The second objective is to develop a general procedure for predicting stormwater runoff pathways in karst regions using GIS technologies and spatial analysis techniques – including identifying which data and techniques are essential to analyze surface and subsurface processes - to improve stormwater monitoring effectiveness. The premise of this study is broken down into a conceptual model with three significant components: Surface Input (stormwater runoff on surface), Subsurface Transport (stormwater transport through subsurface), and Output to Surface (output of stormwater to the surface via springs). The first component utilizes Hydrological Analysis and Network Analysis techniques to determine stormwater runoff pathways from potential point-source pollutant sites across surface to injection points where runoff enters subsurface. The second component uses Spatial Interpolation Techniques and Hydrological Analysis to predict subsurface accumulation areas that collect runoff from injection points and subsurface conduit pathways to output locations. The third and final component examines the output of the runoff back to the surface and identifies the locations where stormwater runoff can be sampled. The analyses of the Surface Input component proved to be effective in predicting the behavior of stormwater runoff between pollutant sites and their corresponding injection points. The analyses of the Subsurface Transport captured the overall patterns in the inferred dye tracing pathways that were used as the control dataset. The Output to Surface established the linkages among RCRA sites, their corresponding injection points and ultimately their output springs. These findings are very useful in developing informed stormwater sampling strategies and plans. In future investigations, these results could be verified with stormwater sampling and additional dye tracings and can be improved in two ways: more complete datasets of all stormwater features in the area – especially springs and drywells, and a more extensive and equally distributed dataset for groundwater depths across the study area to create a more accurate interpolated potentiometric surface.

The purpose of this study is to assess the dewatering requirements of planned open pit nickel mining at &Ccedil / aldag Site in Western Turkey. Dewatering is required for safe and efficient working conditions and pit wall stability. With this scope, a groundwater model of the study area is developed and used to predict the dewatering rate. The methodology mainly involves data collection, site hydrogeologic characterization and development of conceptual model, followed by construction and use of a groundwater model to predict the dewatering requirements of the mine site. The groundwater flow modeling is carried out using MODFLOW software and the dewatering simulations are carried out using MODFLOW Drain package. The drain cell configuration is determined by pit boundaries and invert elevations of drains corresponded to the bench elevations that will be achieved with respect to the mining schedule. In the transient model runs, monthly time steps were used. Using the outflow from in-pit drain cells, the v monthly dewatering rates are calculated. In order to assess the impacts of the hydraulic conductivity of the laterite on the pit inflow rates, simulations were carried out for different values of hydraulic conductivity of laterites. The predicted flow rate using the calibrated model is 107.54 L/s. A tenfold reduction in the hydraulic conductivity of laterite resulted in three fourths of decrease in the flow rate (24.42 L/s). Consequently, a wide range of flow rates for different hydraulic conductivity values of laterite was calculated. In order to confirm the hydraulic conductivity of laterites in the area, and to obtain a realistic dewatering rate, further pumping tests are needed.

Populations residing on and near the world’s coasts have become increasingly dependent on coastal groundwater for their supply of freshwater. Under the conditions of predicted climate changes, the expected rise in global sea level can adversely affect the quality and quantity of freshwater resources in coastal areas as a result of saltwater intrusion. In this study, a suite of two- and three-dimensional variable-density groundwater flow models of major coastal landforms (e.g. deltas, estuaries and small islands) has been constructed to assess the effects of sea level rise (SLR), using different SLR rates of 0.5 m, 1m and 1.5 m over the next 90 years, from 2010-2100. The model results indicate that in natural coastal systems the extent of saltwater intrusion is significantly controlled by the stratigraphy of the depositional environments. Among deltaic aquifers, wave-dominated deltas are more prone to saltwater intrusion than river- and tide-dominated deltas. In case of a partially mixed, microtidal estuary, SLR can cause extensive porewater salinity increases, especially within estuarine sand deposits. Simulations of atoll and barrier islands reveal that carbonate atoll islands with high conductivity units, are severely affected by SLR, resulting in significant reduction of the volume of freshwater lens. In contrast, migrating sandy barrier islands could retain their freshwater resources with rising sea level under conditions of increased recharge, assuming the barriers can migrate in response to SLR. The freshwater lens of barrier island aquifers would reduce in size due to increased evapotranspiration caused by change in vegetation pattern. When examined for anthropogenic impacts of groundwater withdrawal through pumping, all the coastal aquifers show evidence of saltwater intrusion, with varying degrees of impact. Wave-dominated deltas are more affected by groundwater withdrawal than river- and tide-dominated deltaic aquifers. Saltwater intrusion in atoll islands is further enhanced by pumping withdrawal. It is evident from the results of the simulations that, the potential effects on coastal aquifers of groundwater withdrawals for potable water can easily exceed the adverse effects of SLR in terms of salinity increase.

Η παρούσα διδακτορική διατριβή μελετά τις υδρογεωλογικές – υδροχημικές συνθήκες, που επικρατούν στην ευρύτερη περιοχή της αποξηραμένη λίμνης Μουριάς Ν. Ηλείας, με κύριο σκοπό τη δημιουργία μοντέλου ορθολογικής διαχείρισης των υπόγειων νερών. Το γεωλογικό υπόβαθρο της περιοχής έρευνας που περιλαμβάνει τμήμα της υδρολογικής λεκάνης του Αλφειού, τη λεκάνη της Σταφυλίας και τη μεσολεκανώδη των δύο υδρολογικών λεκανών περιοχή, δομούν οι ασβεστόλιθοι ηλικίας Παλαιοκαίνου της Ιόνιας ζώνης και οι εβαπορίτες. Τα μεταλπικά ιζήματα που διαδέχονται τους εβαπορίτες έχουν μεταβαλλόμενο πάχος, που φτάνει τα 2,5km και καλύπτουν σχεδόν ολόκληρη την περιοχή μελέτης. Τα ιζήματα αυτά αποτελούνται από αργίλους, μάργες, ιλυόλιθους και ψαμμίτες σε εναλλαγές. Τρεις κύριες διευθύνσεις ρηγμάτων δημιουργούν ένα πολύπλοκο καθεστώς διάρρηξης στην περιοχή της πόλης του Πύργου. Τα ρήγματα ΒΔ – ΝΑ διεύθυνσης απαντώνται στα νότια και ανατολικά της πόλης του Πύργου, στην περιοχή του Επιταλίου και του Πανόπουλου αντίστοιχα. Ρήγματα διεύθυνσης ΒΑ – ΝΔ απαντώνται βόρεια της πόλης του Πύργου, στην περιοχή του Βουνάργου. Ρήγματα διεύθυνσης Α – Δ απαντώνται στα ΝΑ της πόλης του Πύργου εκατέρωθεν του ποταμού Αλφειού. Η τεκτονική δραστηριότητα και η σεισμικότητα της περιοχής είναι ιδιαίτερα ενεργή μέχρι σήμερα και έχει παίξει καθοριστικό ρόλο στην μεταλπική ιζηματογένεση, στην διαμόρφωση της γεωμορφολογικής δομής, στην ανάπτυξη του υδρογραφικού δικτύου και στην διαμόρφωση των υδρογεωλογικών συνθηκών. Το υδρογραφικό δίκτυο της περιοχής χαρακτηρίζεται ως μέτρια ανεπτυγμένο, με το τεκτονικό καθεστώς της περιοχής να αποτελεί καθοριστικό παράγοντα στη διαμόρφωση και ανάπτυξη του υδρογραφικού δικτύου. Επίσης ένα σημαντικό χαρακτηριστικό γνώρισμα του υδρογραφικού δικτύου της περιοχής είναι η απουσία δέλτα στις εκβολές των ποταμών και των χειμάρρων. Το γεγονός αυτό οφείλεται κατά κύριο λόγο στην έντονη δράση των κυμάτων, καθώς και στις τεκτονικές κινήσεις ανύψωσης των ακτών. Η γεωμορφολογική ανάπτυξη της ευρύτερης περιοχής του Πύργου – Αρχαίας Ολυμπίας χαρακτηρίζεται από ήπιο ανάγλυφο με μεγάλη εξάπλωση της πεδινής ζώνης και ομαλή μετάβαση στην λοφώδη και ημιορεινή ζώνη. Προς τα βόρεια και ανατολικά, καθώς η επίδραση της τεκτονικής είναι εντονότερη, το υψόμετρο της περιοχής σταδιακά αυξάνει και φτάνει μέχρι τα +640m, ενώ το μέσο υψόμετρο είναι +92m. Το μέσο ετήσιο ύψος βροχόπτωσης για την περιοχή του Πύργου είναι 828mm και από την ανάλυση των βροχομετρικών δεδομένων για ολόκληρη την υδρολογική λεκάνη του Αλφειού, προέκυψε μια σχετικά έντονη πτωτική πορεία των ετησίων τιμών βροχόπτωσης κατά τα τελευταία 25 χρόνια και ειδικά η περίοδος 1984-1999 θεωρείται περίοδος ξηρασίας. Ο μέσος ετήσιος όγκος νερού από βροχόπτωση το χρονικό διάστημα 1975 – 2004, ανέρχεται σε 3.962,4x106m3, που αντιστοιχεί σε ένα μέσο ύψος 1.103,7 mm ατμοσφαιρικών κατακρημνισμάτων, κατανεμημένων σε όλη την υδρολογική λεκάνη του Αλφειού. Με βάση το ισοζύγιο κατά Thornthwaite – Mather, οι απώλειες λόγω εξατμισοδιαπνοής υπολογίζονται σε 1.497,05x106m3 νερού ανά έτος, ή 413 mm νερού κατανεμημένων σε όλη την επιφάνεια της περιοχής έρευνας. Η μέση ετήσια ποσότητα νερού που κατεισδύει ανέρχεται σε 1.104,09x106m3 νερού, κατανεμημένων σε όλη την επιφάνεια της περιοχής έρευνας, ή ποσοστό 35,29 % του ύψους βροχής. Από μετρήσεις παροχής στη θέση Φράγμα Φλόκα υπολογίσθηκε ότι ο μέσος ετήσιος όγκος νερού ανέρχεται σε 1.613,36x106 m3. Στην ευρύτερη περιοχή μελέτης αναπτύσσονται υδροφόρα στρώματα τόσο ελεύθερου χαρακτήρα, όσο και υπό πίεση, που ανήκουν στο σχηματισμό του Βουνάργου. Τα υδροφόρα στρώματα που διερευνήθηκαν εντοπίζονται στην πεδινή περιοχή του Πύργου, στην υπολεκάνη του Ενιπέα και στην περιοχή του Βουνάργου, που ανήκει στη λεκάνη της Σταφυλίας. Οι προσχωματικοί υδροφόροι της πεδινής περιοχής παρουσιάζουν τιμές των υδραυλικών ιδιοτήτων, που κρίνονται τυπικές για έναν ελεύθερο υδροφόρο. Οι υπό πίεση υδροφόροι ορίζοντες αναπτύσσονται σε βαθύτερα στρώματα στους ψαμμίτες του σχηματισμού του Βουνάργου και είναι υψηλής δυναμικότητας. Στην πεδινή ζώνη οι ψαμμίτες αυτοί απαντώνται σε βάθος μεγαλύτερο των 30m περίπου και οριοθετούνται από αργιλικά στρώματα. Οι συχνές εναλλαγές στρωμάτων άμμου και αργίλου κατά θέσεις, καθώς και η παρουσία πολυάριθμων ρηγμάτων στο σχηματισμό του Βουνάργου οδηγεί πολλές φορές σε πιθανή μίξη νερών από βαθύτερους υδροφόρους. Η τροφοδοσία του υδροφόρου αυτού γίνεται κυρίως μέσω κατείσδυσης του νερού των βροχοπτώσεων, καθώς και μέσω ρηγμάτων και διαρρήξεων. Από τη μελέτη της πιεζομετρίας της περιοχής του Πύργου διαπιστώνεται ότι ο ελεύθερος υδροφόρος ορίζοντας παρουσιάζει αρνητικές απόλυτες στάθμες στις παράκτιες περιοχές καθ’ όλη τη διάρκεια του υδρολογικού έτους. Αυτό οφείλεται κυρίως στη λειτουργία των αντλιοστασίων για την αποστράγγιση των επιφανειακών νερών της περιοχής, τα οποία στην παράκτια ζώνη αντλούν και μέρος των υπόγειων. Η αριθμητική προσομοίωση του ελεύθερου υδροφόρου ορίζοντα στην περιοχή του Πύργου έγινε με τη χρήση του λογισμικού Flowpath και έδωσε ικανοποιητικά αποτελέσματα όσον αφορά στην προσομοίωση της πιεζομετρικής επιφάνειας αλλά και στην επεξεργασία ενός αξιόπιστου υδρογεωλογικού ισοζυγίου. Σύμφωνα με αυτό, περίπου το 15% του νερού στον υδροφόρο προέρχεται από πλευρικές διηθήσεις του ποταμού Αλφειού, ενώ το υπόλοιπο 85% προέρχεται από την κατείσδυση του νερού των βροχοπτώσεων την χειμερινή περίοδο και των αρδεύσεων τη θερινή περίοδο. Τα αποστραγγιστικά κανάλια παίζουν πολύ σημαντικό ρόλο στην περιοχή, καθώς οδηγούν στα αντλιοστάσια και τελικά στη θάλασσα περίπου το 85% του νερού του υδροφόρου, με το υπόλοιπο 15% να εκφορτίζεται υπόγεια προς τη θάλασσα. Ακόμη το μοντέλο έδωσε τη δυνατότητα πρόβλεψης της συμπεριφοράς του υδροφόρου σε περίπτωση αλλαγής των υδρολογικών συνθηκών στην περιοχή. Στην περιοχή της Μουριάς, όπου τη θερινή περίοδο η τροφοδοσία του υδροφόρου είναι άμεσα συνδεδεμένη με τις αρδεύσεις, παρατηρήθηκε ότι ένας σταθερός όγκος νερού κατεισδύει στον υδροφόρο ακόμα και με μηδαμινές βροχοπτώσεις. Διερευνήθηκε καταρχήν το υποθετικό σενάριο της υψηλής βροχόπτωσης κατά τη χειμερινή περίοδο και προσδιορίστηκε το υδρογεωλογικό ισοζύγιο. Σύμφωνα με αυτό το 82% των εισροών στον υδροφόρο προέρχεται από την απευθείας κατείσδυση του νερού των βροχοπτώσεων και των αρδεύσεων, ενώ το υπόλοιπο 18% διηθείται πλευρικά από τον Αλφειό ποταμό. Το 13% περίπου εκρέει υπόγεια προς τη θάλασσα, ενώ το 87% οδηγείται προς τη θάλασσα μέσω των αντλιοστασίων. Ένα ακόμα υποθετικό σενάριο που διερευνήθηκε ήταν η προσομοίωση του ελεύθερου υδροφόρου ορίζοντα πριν την αποξήρανση της λίμνης Μουριάς τη δεκαετία του 1960. Από την εφαρμογή του μοντέλου και την προσομοίωση της λίμνης Μουριάς, αποδεικνύεται ο ρόλος των στραγγιστικών αντλιοστασίων και των αποστραγγιστικών καναλιών στη διαμόρφωση του υδραυλικού χαρακτήρα της περιοχής, καθώς στο παρελθόν και πριν την αποξήρανση της λίμνης Μουριάς, το υδραυλικό φορτίο ήταν υψηλότερο σε ολόκληρη την περιοχή κατά 2m περίπου. Ενδιαφέρον επίσης παρουσιάζει το γεγονός, ότι σύμφωνα με το υδρογεωλογικό ισοζύγιο οι πλευρικές διηθήσεις από τον ποταμό Αλφειό προς τον υδροφόρο ορίζοντα εμφανίζονται μειωμένες κατά 10% περίπου σε σχέση με την σημερινή κατάσταση. Αυτό αποδίδεται στο γεγονός ότι η παρουσία των στραγγιστικών αντλιοστασίων (και ειδικότερα αυτού που απέχει 500m από τον Αλφειό) δημιουργούν αναρρόφηση νερού από τον ποταμό ενισχύοντας έτσι την πλευρική διήθηση. Ακόμη παρατηρήθηκε ότι η κατανομή των πιεζομετρικών καμπύλων παρουσιάζεται περισσότερο ομοιόμορφη σε σχέση με τις σημερινές συνθήκες. Σε ορισμένες θέσεις στον ελεύθερο υδροφόρο ορίζοντα της περιοχής του Πύργου παρουσιάζονται φαινόμενα ιοντοανταλλαγής, λόγω της διείσδυσης του θαλασσινού νερού προς την ενδοχώρα. Οι θέσεις αυτές εντοπίστηκαν κυρίως σε μία ζώνη παράλληλη της ακτογραμμής, η οποία καταλαμβάνει το ανατολικό τμήμα της αποξηραμένης λίμνης Μουριάς και εκτείνεται έως τον ποταμό Αλφειό. Επίσης παρατηρήθηκε το φαινόμενο της αποδολομιτίωσης και της οξείδωσης του σιδηροπυρίτη, ενώ οι ανθρωπογενείς επιδράσεις αντανακλώνται από τις υψηλές συγκεντρώσεις κυρίως των ενώσεων του αζώτου. Τα φαινόμενα αυτά επιβεβαιώθηκαν και από την παραγοντική ανάλυση, η οποία πραγματοποιήθηκε για τα κύρια στοιχεία και τα ιχνοστοιχεία του ελεύθερου υδροφόρου ορίζοντα. Στη χημική σύσταση του νερού των αποστραγγιστικών καναλιών οι συγκεντρώσεις των στοιχείων είναι αυξημένες κυρίως στην παράκτια ζώνη, και αυτό μπορεί να οφείλεται τόσο σε επίδραση από το θαλασσινό νερό, όσο και σε ρύπανση από ανθρωπογενείς παράγοντες. Οι μέγιστες τιμές που λαμβάνουν τόσο τα κύρια στοιχεία, όσο και τα ιχνοστοιχεία καθιστούν τα επιφανειακά αυτά νερά ακατάλληλα για κάθε χρήση, καθώς στα κανάλια καταλήγουν συχνά οικιακά και βιομηχανικά απορρίμματα εμπλουτίζοντας το νερό σε βαρέα μέταλλα. Στα πλαίσια της παρούσας διατριβής η ερευνητική ομάδα του προγράμματος ΠΕΝΕΔ κατασκεύασε σε μία έκταση 5 στρεμμάτων στο ανατολικό άκρο της αποξηραμένης λίμνης Μουριάς μία πειραματική λίμνη. Το βρόχινο νερό που κατέκλυσε την εκσκαφή της νέας λίμνης, ήρθε σε επαφή με τα αργιλικά ιζήματα που κυριαρχούν στην περιοχή και μέσα σε μικρό χρονικό διάστημα το νερό απέκτησε υψηλές συγκεντρώσεις στοιχείων. Οι υψηλές συγκεντρώσεις σε σίδηρο και μαγγάνιο των δειγμάτων νερού του υπό πίεση υδροφόρου της περιοχής του Πύργου είναι ο κυριότερος λόγος για την ακαταλληλότητά τους. Η επικράτηση αναγωγικών συνθηκών σε μεγάλο τμήμα του υδροφόρου ευνοεί τις υψηλές συγκεντρώσεις των στοιχείων αυτών. Η υδροχημική έρευνα στα δείγματα νερού του υπό πίεση υδροφόρου ορίζοντα του σχηματισμού του Βουνάργου έδειξε ότι τα νερά αυτά έχουν γρήγορη ανανέωση σε σχέση με τον υπό πίεση υδροφόρο της περιοχής του Πύργου και η τροφοδοσία τους γίνεται από βόρειες και ανατολικές διευθύνσεις. Η παρουσία H2S σε συνδυασμό με τις αυξημένες συγκεντρώσεις NH4+ και βορίου οφείλονται στην πιθανή ανάμιξη του νερού με θερμομεταλλικά νερά, που βρίσκονται βαθύτερα και αναδύονται μέσω ρηγμάτων. Στην υδρολογική λεκάνη της Σταφυλίας και ειδικότερα κατά μήκος της ρηξιγενούς ζώνης Βουνάργου – Κατακόλου διαπιστώθηκε η ύπαρξη νερών με ιδιαίτερα υδροχημικά χαρακτηριστικά, όπως οι υψηλές συγκεντρώσεις νατρίου, η έκλυση μεθανίου, υδροθείου κ.ά. Οι υψηλές συγκεντρώσεις CO2 σε συνδυασμό με την ύπαρξη ραδονίου στα υπόγεια νερά θεωρείται ότι οφείλονται στην ύπαρξη θερμομεταλλικής υδροφορίας, η οποία εκδηλώνεται σε μία επιμήκη ζώνη παράλληλη στο ρήγμα του Βουνάργου. Οι θερμομεταλλικές εμφανίσεις της περιοχής πιθανά συνδέονται με την κατείσδυση μετεωρικού νερού σε μεγάλα βάθη μέσω μεγάλων τεκτονικών ασυνεχειών. Σε μεγάλα βάθη το νερό έρχεται σε επαφή με εβαπορίτες και εμπλουτίζεται με θειικά ιόντα, τα οποία λόγω του αναγωγικού περιβάλλοντος ανάγονται σε υδρόθειο. Η άνοδος του θερμομεταλλικού νερού προς την επιφάνεια γίνεται μέσω τεκτονικών ασυνεχειών. Στην πορεία του αναμιγνύεται με νερά υδροφόρων οριζόντων, που βρίσκονται σε μικρότερο βάθος με αποτέλεσμα η θερμοκρασία του να μειώνεται, προκαλώντας παράλληλα μεταβολή του υδροχημικού χαρακτήρα των υδροφόρων αυτών. Η εφαρμογή της μεθόδου DRASTIC στην περιοχή του Πύργου οδήγησε στην δημιουργία ενός μοντέλου τρωτότητας του ελεύθερου υδροφόρου ορίζοντα με βάση τους ρύπους που εισάγονται στην επιφάνεια του εδάφους. Η τροποποίηση της αρχικής μεθοδολογίας ως προς τις τιμές των παραμέτρων, αλλά και της βαρύτητας των συντελεστών, επέφερε ικανοποιητική συσχέτιση μεταξύ της ενδογενούς τρωτότητας και της συγκέντρωσης του ολικού αζώτου. / The present thesis deals with the hydrogeological – hydrochemical conditions that dominate in the wider area of the former Mouria Lake, in Ilia Prefecture, in order to develop a model for rational management and protection of aquifers. The bedrock in the research area, which comprises part of the hydrological basin of the Alfios River, the Staphylia Basin and the intrabasinal region, is formed of Paleocene limestone of the Ionian zone and the evaporites. The post-alpic sediments that overly the evaporites, have a varying depth that is up to 2.5km, covering almost the entire study area. These sediments consist mainly of clay, marl, siltstone and sandstone. Three major fault trends develop a complex fault system in the Pyrgos area. The NW – SE fault trends are in the south and east part of Pyrgos town, while the NE – SW trending faults occur in the area of Vounargo village. The E – W trending faults are found in the SE part of Pyrgos town, parallel to Alfios River valley. The tectonics and the seismicity of the study area is active until today and has played a prominent role in the post-alpidic sediments, as well as in the shaping of today’s relief, in the development of the drainage network and the local hydrogeological characteristics. The hydrographic network in the study area is relatively well developed, while active tectonics is the major factor in the development of the hydrographic network. Another basic characteristic of the hydrographic network is the absence of delta in the river estuaries. This is mainly due to the wave action, as well as to the tectonic uplift of the coastline. The geomorphological development of the entire area is characterized by a smooth relief. It is a flat to semi-mountainous region, with a mean altitude of +92 m, which diminishes gradually westwards. The mean annual precipitation in the Mouria area amounts to 828mm. From the precipitation data analysis for the whole Alfios Basin, a rather gentle declining trend of the mean annual values in the last 25 years, with a relatively more sharp decline in the period 1984-1999 can be observed. The mean annual volume of precipitation for the period 1975 – 2004 is 3.962,4x106m3 distributed in the whole Alfios basin. According to the Thornthwaite – Mather ‘s hydrological balance, 1.497,05x106m3 of water evapotranspirate annually, which equal to 413 mm distributed in the whole Alfios Basin. The average annual volume of water that infiltrates to the aquifers amounts to 1.104,09x106m3 for the Alfios Basin, which is 35.29 % of the rainwater. As derived from runoff measurements in Flokas Dam, 1.613,36x106 m3 of water annually, flows into the sea. In the broad study area several aquifers develop in different geological layers both unconfined and confined at greater depths in the Vounargo Formation. The aquifer layers studied are located in Pyrgos area, in the sub basin of Enipeas River (Alfios tributary) and in Staphylia Basin. The alluvial aquifers appearing in the lowland area, have typical hydraulic characteristics of unconfined aquifers. The confined aquifer bodies are developed in the deepest sandstone layers of the Vounargo Formation. In the lowland area these sandstones are found deeper than 30m intercalating with shales. The alterations of sand and clay is very common in many places and in addition to the presence of a number of faults in the Vounargo Formation, they result in water mixing from deeper aquifers to upper water bodies. The recharge of the confined aquifer is through infiltration of rainwater, as well as through faults and discontinuities that allow surface water to reach the aquifer bodies. From the study of the piezometrical maps in Pyrgos area, it is shown that the alluvial aquifer in the lowland area has a negative hydraulic gradient throughout the hydrological year. This is due to the use of pump stations that cause severe drawdown, especially in the coastal zone as the drainage channels connect to the aquifer at that area. The numerical simulation of the alluvial aquifer in Pyrgos area was done using Flowpath software. The results were very satisfying regarding both the simulation of the piezometrical surface and the reliable hydrogeological balance. According to this, 15% of the aquifer water derives from lateral leakage from Alfios River, while 85% derives from infiltration of the rainwater during the winter period and irrigation water during the summer period. The drainage channels play a very important role in the area as they lead 85% of the groundwater to the sea and the rest 15% is underground runoff towards the sea. Additionally, the prediction of the aquifer’s piezometrical surface and balance in case stresses change, was checked by the use of the Flowpath. In the study area the aquifer is constantly recharged throughout the year even during the summer due to the water use for irrigation. So the scenario that was checked, was that of heavy rainfall and the hydrological balance was checked for the new stress period. According to the results, 18% of the aquifer water derives from lateral leakage from Alfios River, while 82% derives from infiltration of the rainwater during the winter period and irrigation water during the summer period. Another hypothesis, is of simulating the aquifer before the drainage of the Mouria Lake that took place in 1960 ‘s. Results show that the role of drainage channels is significant for the study area as in the past decades before the drainage of the Mouria Lake the groundwater level was 2 meters higher. According to the hydrogeological balance, the lateral leakage from the Alfios River is decreased 10% in relation to the present situation. Ion–exchange phenomena are taking place in the alluvial aquifer of Pyrgos, due to seawater intrusion towards the inner land. This takes place especially in a zone parallel to the sea shore extending from the former Mouria Lake to Alfios River. Moreover, dedolomitization and pyrite oxidation are taking place in the aquifer, whereas high concentrations of ammonia is attributed to anthropogenic contamination. These phenomena were confirmed also by the factor analysis applied to the major and trace element contents. As regards the chemical composition of the drainage channels, the high concentrations of elements, especially in the coastal zone, are attributed not only to seawater intrusion but also to anthropogenic contamination. The maximum values of major and trace elements show that channel water is inappropriate for any use, as house and fabric waste usually are found in those channels thus enriching water with heavy metals. In the frame of the PENED project, the project team designed and constructed a lake in a 0.5-ha large area, in the eastern part of the drained Mouria lake. The rainwater that flooded the new lake became saline during its 3-month interaction with the clay sediments that dominate in the area. High concentrations of iron and manganese in water samples from the confined aquifer in the Pyrgos area are the main reason for their inappropriateness. The domination of reducing conditions in a big part of the aquifer favors the existence of those elements. The hydrochemical research in the samples of the confined aquifer in Vounargo Formation showed that there is a quick recharge in relation to the confined aquifer in Pyrgos area and their recharge is from the north and east part of the study area. The presence of H2S along with the high concentrations of NH4+ and B, are attributed to possible mixing with thermal waters that are found deeper and come upwards through faults. In the Staphylia Basin and especially along the Vounargo–Katakolo fault zone, the existence of waters with special characteristics was studied, like high sodium concentrations, methane release etc. High CO2 and Rn concentrations in groundwaters are attributed to the thermal waters and their existence near the Vounargo fault zone. The thermal waters in the area are possibly connected to the infiltration of meteoric water in great depths via large tectonic discontinuities. At great depths the water contacts the evaporites and enriches in sulfate ions that reduce to sulphuretted hydrogen, due to the reducing conditions. The uplift of the thermal water towards the surface is done through rock discontinuities, while it mixes with water bodies of upper layers, resulting in the decrease of its temperature, but at the same time causing changes in the hydrochemical type of the upper aquifers. The DRASTIC method was applied in the Pyrgos area and led to the development of the intrinsic vulnerability model of the alluvial aquifer, based on contaminants injected to the land surface. The modification of the initial methodology as regards the parameter values and the weight factors resulted in satisfying correlation between the intrinsic vulnerability and the concentration of total nitrogen.

På en fastighet i Luthagen i Uppsala uppfördes en byggnad grundlagd på träpålar år 1936. Under 60-talet uppstod läckage på en spillvattenledning vilket ledde till en kontaminering av sprickvattenakviferen där träpålar är särskilt utsatta för påverkan av bakterie, svamp- och virusangrepp till följd av torrläggning. För att spola bort kontaminerat sprickvatten och för att hålla en jämn sprickvattennivå i akviferen installerades påfyllningsbrunnar på två platser i källaren under huset. Brunnarna är driva ner i de pålrännor där träpålarna är slagna. Den normala vattentillförseln låg under flera decennier på runt 10 m3/år och vattennivåerna övervakades av bostadsföreningens fastighetstjänst med regelbundna observationer av sprickvattennivån. Under hösten 2016 skedde ett trendbrott och förbrukningen av dricksvattenpåfyllning på över 10 m3/dygn uppmättes. Vattenförbrukningen fortsatte att öka och var vid vissa perioder uppe på nästan 20 m3/dygn. Bjerking AB fick då i uppdrag att undersöka orsaken till den ökade vattenförbrukningen och var vattnet tog vägen. I samband med upptäckten av den ökande vattenförbrukningen skedde även ett brott på en kommunal vattenledning i Kyrkogårdsgatan. Akviferen antogs vara i princip tät och borde inte haft någon hydraulisk kontakt med det vattenförande moränlagret under leran. Syftet med följande rapport är att undersöka de flöden som sprickvattnet har och försöka bestämma den förhärskande flödesriktningen. Den frågeställning som valts är baserad på möjligheten att modellera flödet i grundvattenmodelleringsprogrammet GMS-MODFLOW. Frågeställningen är följande För att sedan kunna modellera grundvattenflödet användes parameter estimation (PEST) som utgår från det framkalibrerade initialt grundvattenförhållandet. Där efter bestäms ett antal zoner som programmet sedan beräknar fram den hydrauliska konduktiviteten för respektive zon. Modelleringen med PEST gav resultat som visar på höga hydrauliska konduktiviteter i husets sydvästra kortsida. Den transienta modelleringen utfördes genom att de observerade vattennivåerna som mätts upp under avstängningsförsöket jämfördes med beräknade värden som fåtts genom modellen. Resultaten visade då på att be beräknade vattennivåerna till viss del stämmde över ens med de observerade, även om de var förskjuta från varandra med nästan 0,6 meter. Denna skillnad berodde antagligen på det gränsvärde som satts för randvillkoret i modellen på 7,25. Vilket gjorde att inga vattennivåer kunde bli högra än detta, vilket som tolkades som att det förekom trösklar i rännorna. Dessa resultat stämmer överens med den hypotes som antogs före projektstarten och innebar att den mest troliga flödesriktningen skulle vara åt sydväst och husets kortsida. Att resultaten bevisar antagandet säger att modellen som byggdes är mer eller mindre rättvisande. Det är dock mycket osäkerheter i modellen och de ingångsvärden som använts. Bland annat är materialtyperna som finns i modellen enbart antagna och det har inte gjorts några bestämningar av markens hydrauliska egenskaper. Andra möjliga fel som kan ha påverkat resultaten är de skalningsproblem som finns i MODFLOW. Slutsatsen är att det är möjligt att göra denna typ av ”småskalig” flödesmodellering i MODFLOW och att förhärskande flödesriktningen är åt sydväst och husets kortsida. / Most of Sweden’s older buildings constructed in clay rich areas are founded on wood poles. The poles are used to build the constructions in areas with soils without satisfying stability, such e.g. clay soils, where the poles are used as the “stable ground” where the building are founded upon. One of the problems with wood poles are that to prevent the wood from rotting the poles must be covered with water, to make an oxygen free environment. The problems start first when the water levels start to decrease due to dewatering or if the water is contaminated with bacteria from e.g. leaky sewer pipes. The contamination leads to decomposing of the wood, which affect the stability of the poles negatively. To prevent the leaky aquifers many houses, have water supply by wells where water is added to the aquifer to keep the water at stable levels. In Uppsala, Sweden an apartment building founded on wood poles have this problems with a contaminated and leaky aquifer. The reason to the contamination was an old sewer pipe that start leaking due to subsidence of the clay below the house. The dewatering of the aquifer was detected in 2016 when the water supply to the aquifer increased from 10th of cubic meters per year to 10th of cubic meters per day. In an attempt to find out what the reason to the high discharge from the aquifer a groundwater model was constructed to modelling the groundwater flows below the building. To modeling this problem the software Groundwater Modeling System (GMS) and MODFLOW was used. By construct a 3D grid of cells in the same dimensions as the building divided in to three different layers it was possible to simulating the groundwater flow through the aquifer. The way we did it was by knowing that as part of the foundation there was “channels” filled with gavel above the poles. The hypothesis was that the water was flowing through this high hydraulic conductivity “gravel channels” and there for we used the model to performed calculations of the hydraulic conductivity in the channels and the areas around the channels. The results told us that there were high conductivity zones in the south west part of the building. After the calculation of the conductivity, a test was performed, where the water supply where turned off and the decrease of the water levels was measured. By using this calculated hydraulic conductivity and the observed levels from the water supply test we let the model calculate the change of water level during the whole-time series. The results told us that there was a possible groundwater flow to the sought west and that some sort of threshold in the channel prevented the water to sink below a curtain limit of 7.65 meter.