Dissertations / Theses on the topic 'FEFLOW'

The need of understanding transport processes of contaminants in groundwater has grownalong with the discovering of contamination of soil and groundwater due to industrialization.Mobility of an organic contaminant in the soil is affected by its partitioning to dissolvedorganic carbon, DOC. Partitioning of hydrophobic organic contaminants, HOCs, to DOC isdescribed by the contaminant’s KDOC value. The effects of DOC on transport processes oforganic contaminants with groundwater are still relatively unexplored even though somereviews have been carried out in this particular field of research. The aim of this thesis workwas to investigate transport processes for the PAH phenanthrene and the phthalate Di(2-ethylhexyl) phthalate, DEHP, with DOC by constructing a transport model with the computerprogram FEFLOW 6.1. The thesis work was performed as part of an ongoing Research &Development project investigating alternative remediation techniques at Domsjö industrialsite, located 2 km south of Örnsköldsvik. Generally, the groundwater at the site was characterized by low phenanthrene and DEHPcontent together with high DOC content. In the sampling points with highest reportedcontaminant concentration also DOC was present in highest concentrations. During theperformed literature study it was found that tabulated KDOC values for phenanthrene wasavailable but not for DEHP, which had to be calculated based on available KOC and KOWvalues. Five different modeling scenarios were developed: 1. Transport of phenanthrene with KDOC minimum value. 2. Transport of phenanthrene with KDOC maximum value. 3. Transport of phenanthrene with KDOC median value. 4. Transport of DEHP with KDOC calculated with KOC. 5. Transport of DEHP with KDOC calculated with KOW. Calculations of contaminant concentration in groundwater were made with an equation thatrequires both site and contaminant specific constants. These constants had to be estimatedduring this thesis work, which resulted in insecurities possibly affecting the model results.However, the minimum and the median value of KDOC showed best modeled phenanthreneconcentration after six years compared to measured values. Best result of modeledconcentrations of DEHP was obtained with KDOC calculated with KOC. Correlation analysis ofDOC and contaminants showed a significant correlation between DOC and phenanthrene at99% confidence level, and between DOC and DEHP at 90% confidence level.
I takt med ökad kännedom om industriellt förorenade områden har det också blivitbetydelsefullt att känna till de processer som påverkar transport av föroreningar medgrundvattnet. Rörligheten av en hydrofobisk organisk förorening, HOC, påverkas av dessfördelning till löst organiskt kol, DOC, och beskrivs med fördelningskoefficienten KDOC.Effekterna av DOC på föroreningstransporten är relativt okända trots att forskning harbedrivits inom området. Syftet med examensarbetet var att undersöka spridning av fenantren(ämnesklass PAH) och Di(2-etylhexyl)ftalat med DOC genom att konstruera enföroreningsspridningsmodell i datorprogrammet FEFLOW 6.1. Examensarbetet utfördes somdel i ett pågående Forsknings & Utvecklingsprojekt med syfte att utreda en alternativsaneringsteknik för Domsjö industriområde, 2 km söder om Örnsköldsvik. Generellt sett karaktäriserades grundvattnet på platsen av låg fenantren- och DEHP-halttillsammans med hög DOC-halt. På samma ställen där föroreningarna förekom i högstakoncentration var också DOC-koncentrationen som högst. Vid genomförd litteraturstudieåterfanns tabellerade KDOC-värden endast för fenantren. KDOC för DEHP saknades och fickberäknas med ekvationer baserat på förhållandet mellan KDOC och KOC respektive KOW. Femolika modelleringsscenarier utvecklades: 1. Spridning av fenantren med minsta tillgängliga KDOC-värde. 2. Spridning av fenantren med högsta tillgängliga KDOC-värde. 3. Spridning av fenantren med median KDOC-värde. 4. Spridning av DEHP med KDOC beräknat med KOC. 5. Spridning av DEHP med KDOC beräknat med KOW. Beräkning av föroreningarnas koncentration i grundvattnet gjordes med en ekvation somegentligen kräver både plats- och föroreningsspecifika konstanter. Då detta inte fanns att tillgågjordes uppskattning av värdena vilket resulterar i osäkerheter som kan ha påverkan påmodellerade resultat. De bästa modellerade koncentrationerna av fenantren efter sex årssimulering jämfört med uppmätta koncentrationer uppnåddes med minsta och median-värdeav KDOC. Bästa modellerade koncentrationerna av DEHP gavs av KDOC beräknat med KOC.Korrelationstest med DOC och respektive förorening visade en signifikant korrelation mellanDOC och fenantren vid 99% konfidensnivå, och mellan DOC och DEHP vid 90% konfidensnivå.

Geólogo
Ante la tarea de proponer nuevas metodologías para la caracterización y modelación de reservorios fracturados se propone la implementación en el software FEFLOW 7.1 de un modelo de fractura simple que represente la inyección de soluto implementada en el sitio de experimentación de rocas fracturadas de Ploemeur, Francia y considerando un escenario de inyección de un pulso de calor para observar la respuesta del modelo en función de unas consideraciones experimentales propuestas para el sitio. La calibración del modelo se realizó ajustando las curvas numéricas entregadas por el software a la respuesta másica experimental en conjunto con una curva calórica propuesta (y posible de encontrar en la zona), por medio de iteraciones desde un resultado inicial, obtenido desde los parámetros default del software y de acuerdo con la ley cúbica. El modelo conceptual por representar corresponde a una discontinuidad horizontal que separa 2 grupos de capas (layers) sobre el cual se simularon dos pozos (inyección y recuperación) separados horizontalmente por 10.8m. Los tiempos de llegada de trazador bordean los 30 minutos mientras que la respuesta calórica propuesta ronda las 50 horas. Dentro de los grandes controladores de la llegada de masa y calor al pozo de recuperación se encontraron la conductividad hidráulica y no así el espesor de fractura, además de tener efectos más intensos en el transporte calórico que en el másico. Factores como reacciones de sorción o efectos difusivos a esta escala local no tienen efectos notorios, sin embargo, a la hora de estudiar circulación a escala regional deben ser cuantificados y revisitados. El ajuste propuesto es bueno, tanto estadística como visualmente. Los análisis de sensibilidad efectuados sobre el ajuste muestran la existencia de propiedades críticas como la porosidad de los elementos circundantes y la dirección de gradiente hidráulico utilizado. La determinación en terreno de este parámetro resulta fundamental para obtener una primera aproximación fidedigna de los parámetros del acuífero y su determinación no debiera revestir mayor dificultad, ya que puede aprovecharse la implementación de los pozos para obtener dichos valores. Como suele suceder en toda simulación, resulta de primera necesidad la corroboración de los datos experimentales en terreno. En caso de que la configuración experimental no entregue los resultados propuestos para la calibración del transporte de calor, deben revisitarse los supuestos del modelo y acotar mejor el problema, ya que se estaría llegando a configuraciones hidrogeológicas que no representen de la mejor forma la situación real del acuífero. Finalmente, al considerar la extrapolación de los resultados a zonas de interés tanto chilenas como extranjeras debe tenerse en consideración el cambio de escalas y lo que esto conlleva: distintos tamaños de bloque y mayores tiempos de cómputo con requerimientos computacionales superiores. Así, implementar esta metodología es una buena primera aproximación al desafío del flujo y transporte en rocas fracturadas. Dentro de sus ventajas está la de necesitar pocos parámetros de entrada y pruebas de campo, por lo que puede considerarse como una opción viable antes de realizar modelos más complejos y robustos pero que requieren de mayor cantidad de información base.
Este trabajo ha sido financiado por el Proyecto FONDECYT 1170569 y el Proyecto UNESCO IGCP636

Por años, la humanidad ha intentado aproximarse a las complejidades de la naturaleza, formulando principios y herramientas numérica para la modelación del escurrimiento subterráneo, el aprovechamiento de data medida en campo (piezómetros, registros de sondeos diamantinos y aforos) y análisis estadístico, permite proyectar y/o proponer modelos de flujo (circulación) dentro de unidades geológicas, como es el caudal de filtraciones una variable dependiente, y su importancia de ser estimado y drenado adecuadamente conllevaría a establecer indicadores de monitoreo y control del caudal dentro de masas geológicas. La información que fue recopilada e interpretada, está en función a la data obtenida de campo, los cuales permitieron proponer un modelo conceptual de flujo que considerase las características del o los macizos rocosos presentes en el Derrumbe 5, estableciéndose una primera estimación del caudal de filtraciones dentro de estas masas geológicas. El modelo conceptual de flujo y geológico inferido, fue implementado usando el código FEFLOW 7.1, permitiendo establecer una solución de aproximación numérica bajo la técnica de elementos finitos, asignándose condiciones iniciales y valores de permeabilidad para cada masa geológica de constitución compleja, la comparación de los datos observados en campo versus los resultados del modelo numérico, permitió establecer la curva de calibración, obteniéndose resultados RMS por debajo del 5%, Anderson (1986), valor aceptable en técnicas de modelación, los valores que fueron estimados para el caudal de filtración en las galerías se estimaron en el orden 2.1 l/s a 5.0 l/s basada en la interpretación de los datos medidos en campo (aforos) versus los estimados numéricamente.
For years, the human being has tried to approximate the complexities of nature, the principles and the numerical tools for the mode of superficial and subterranean clarification, the use of the data measured in the field (piezometers, records of diamond drilling and gauging) and its statistical treatment, allows to infer and / or predict flow models (circulation) within the geological masses, this flow of filtrations being a dependent variable, and its importance to be estimated and drained adequately, as well as to the monitoring indicators and control of the flow within geological masses. The information that was collected and interpreted, is based on the data obtained from the field, which allowed us to propose a conceptual flow model that considered the characteristics of the rock mass (s) present in Collapse 5, and establishing a first estimate of the flow of leaks within these geological masses. The conceptual model of inferred flow and geology was implemented using the FEFLOW 7.1 code, allowing to establish a numerical approximation solution under the finite element technique, assigning initial conditions and permeability values for each geological mass of complex constitution, comparing the data observed in the field versus the results of the numerical model, allowed to establish the calibration curve, obtaining RMS results below 5%, acceptable value in modeling techniques, the values that were estimated for the flow of filtration in the galleries were estimated in the order 2.1 l / s at 5.0 l / s based on the interpretation of the data measured in the field (aforos) versus the numerically estimated ones.
Tesis

Propone un primer modelo conceptual hidrogeológico local en la zona del Derrumbe 5. Caracteriza los acuíferos presentes en la superficie y en la profundidad, y aplica una modelación numérica con FEFLOW+FMH3, con la finalidad de plantear las obras de drenaje y subdrenaje, que permitan mejorar la resistencia de los suelos y modifiquen los parámetros de resistencia en cada unidad geológica. Analiza los efectos derivados del ciclo del agua local, mediante la cuantificación y delimitación de áreas de drenaje y su relación con las condiciones hidrogeológicas (tipos de acuíferos). Identifica las zonas de recarga y descarga e interpreta el modelo conceptual de interacción de escorrentía superficial, subsuperficial y subterránea. En función de la información geológica-geotécnica disponible, comprende las unidades hidrogeológicas in situ, con fines de estimar el movimiento del flujo en medios porosos. Predice escenarios hidrogeológicos considerando las obras de estabilización para el deslizamiento, y su relación con los límites del acuífero interpretado. Aplica el modelo FEFLOW+FMH3, para predecir las trayectorias y tasas de flujo de agua, que convergen a las masas del deslizamiento denominado Derrumbe 5, con fines de proyectar las obras civiles de captación subterránea.
Tesis

Ingeniero Civil
El trabajo de título se centró en la aplicación de la herramienta FEFLOW para la modelación y evaluación numérica de flujos de aguas subterráneas, en base a elementos finitos, en la zona saturada y no saturada del suelo. Se presenta un caso de estudio que fue analizado por la consultora de ingeniería ambiental Knight Piésold mediante la utilización, en conjunto, de otras herramientas de modelación como Visual Modflow y SEEP/W. Estos programas se complementan para analizar los flujos involucrados en la zona saturada y no saturada respectivamente, consignándose como una metodología a comparar frente a FEFLOW. Es así que se presenta como objetivo principal analizar la aplicabilidad, manejo y resultados numéricos de FEFLOW frente a lo realizado con Visual Modflow y SEEP/W. El desarrollo del trabajo consideró un análisis a las metodologías implementadas en la modelación de cada programa. De acuerdo a esto se presentan los resultados y pasos a seguir en la definición de la zona de modelación y sus condiciones de borde, interpolación topográfica y ajustes en la calibración de la zona saturada como de la no saturada de acuerdo a cada herramienta utilizada. Para complementar el estudio se realizó un análisis de sensibilidad del programa FEFLOW en función del número de elementos utilizados en la generación de la grilla de modelación y así conocer la influencia de esta variable en el modelo. Los resultados de ambas metodologías enfrentadas resultaron ser consistentes entre ellas y en línea a las consideraciones en la modelación. A su vez se analizaron las diferentes complejidades a enfrentar en la generación de un modelo con estas herramientas, por lo que la comparación no solo radica en elementos numéricos, si no también en las dificultades que el usuario debe hacer frente. Se concluye con un análisis a los objetivos y consideraciones más importantes observadas durante el estudio, tales como la utilización de programas basados en diferencias finitas y elementos finitos, la metodología en la caracterización de la zona no saturada, la modelación de una geometría compleja y la aplicabilidad del programa FEFLOW.

L’importanza dell’acqua sia per la vita, sia come componente dell’ecosistema globale sta diventando sempre più evidente. Essa è una risorsa che non solo soddisfa i bisogni fondamentali della popolazione umana, ma è anche vitale per tutti gli ecosistemi globali. Una domanda ricorrente è quella di trovare soluzioni per sopperire alla carenza di acqua che si avverte nei periodi estivi; questo “stato di calamità” va a dimostrare la scarsa conoscenza idrogeologica della risorsa idrica disponibile. Il tutto si traduce in una mancanza di strumenti idonei per affrontare con competenza e con tranquillità anche le situazioni più critiche che si possono presentare. L’obiettivo fondamentale di questo progetto è quello di mostrare come il monitoraggio delle falde sotterranee e l’applicazione della modellazione numerica allo studio degli acquiferi possa fornire un valido supporto scientifico alla progettazione e alle politiche di gestione per il corretto utilizzo e la salvaguardia delle risorse idriche del territorio. Nello specifico, è stato preso come riferimento il territorio del Bacino trasfrontaliero del Fiume Roia concentrando le analisi soprattutto nella parte sud dello stesso, in un’area di circa 1,8 km2, collocata poco a nord dell’abitato di Ventimiglia, dove il Fiume Roia si incontra con il suo maggiore affluente, il Torrente Bevera. L’acquifero presente in quest’area, per quantità e qualità, è uno dei più importanti serbatoi naturali della Liguria. Per quanto riguarda l’utilizzo della risorsa, infatti, le sue acque soddisfano i fabbisogni idrici sia del territorio francese (Mentone, Nizza, Montecarlo, ecc.) sia del territorio italiano (Ventimiglia, Bordighera, Imperia, Sanremo, ecc.), “dissetando” circa 350.000 utenze in Italia e circa 120.000 utenze in Francia. In particolare, questo studio idrogeologico, dopo una preventiva analisi ed un monitoraggio di dati di natura idrologica e idrogeologica (dati pluviometrici, idrometrici, piezometrici, di portata fluviale e di qualità delle acque sotterranee), ha affrontato la ricostruzione geometrico-strutturale del sottosuolo sulla base delle indagini geognostiche a disposizione grazie alle quali è stata evidenziata la presenza di un unico corpo acquifero, a falda libera, di spessore medio di circa 29,8 m, composto in prevalenza da ghiaie sabbiose, talvolta limose, con ciottoli e caratterizzato da un elevato grado di permeabilità (0,8-1 × 10-2m/s), limitato alla base da un substrato a bassa permeabilità costituito dai Flysch di Ventimiglia. E’ stata definita la caratterizzazione idrodinamica dell’acquifero mediante l’utilizzo dei dati raccolti durante una campagna di rilevamento piezometrica su 28 punti di misura nel periodo Luglio 2012 – Luglio 2013. Sulla base di queste conoscenze è stato realizzato il modello concettuale dell’acquifero, base fondamentale della modellazione numerica. Il sistema acquifero è stato quindi rappresentato, per mezzo di un modello numerico tridimensionale ad elementi finiti (FEM), con l’utilizzo del codice numerico FEFLOW (Finite Element subsurface FLOW system), operando in regime permanente e transitorio. I dati di input sono stati inseriti el sistema attraverso l’assegnazione di condizioni ai limiti (Boundary Condition) di carico idraulico, di trasferimento di flussi, di emungimenti e delle proprietà dei materiali (Material Properties) come la permeabilità, la porosità e l’infiltrazione. I risultati finali hanno permesso di stimare i quantitativi d’acqua presenti all’interno della porzione di acquifero in studio mettendo in risalto l’importanza e il ruolo che ricopre il fiume Roia e la quantità d’acqua che esso scambiata con la falda idrica che riesce a bilanciare e a mantenere in equilibrio tutto il sistema anche a fronte dei circa 44 × 106 m3 annui (circa 1,4 m3/s) prelevati dai pozzi presenti. Al fine di mostrare le potenzialità di questa tipologia di studio e ipotizzare possibili scenari di sfruttamento futuro 3 scenari di flusso dove si è ipotizzato un incremento dello sfruttamento della falda a scopo idropotabile. I risultati hanno messo in evidenza le enormi potenzialità di questo acquifero, il quale risulta in grado di sostenere fino ad un incremento del 70% delle attuali portate emunte, purché esse siano ben distribuite e non concentrate in un unico punto. Infine è stata effettuata la modellazione di trasporto dove sono stati analizzati due probabili scenari di inquinamento che hanno messo in evidenza quanto l’acquifero risulti essere suscettibile all’inquinamento idroveicolato da cui deriva, conseguentemente, la necessità di progettare adeguate misure per la sua salvaguardia, anche per l’importanza che esso ricopre come fonte strategica di approvvigionamento idropotabile.

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A gestão adequada dos recursos hídricos é peça-chave para o desenvolvimento de uma região, seja urbana ou agrícola. O conhecimento acerca do impacto das mudanças climáticas e as diferentes atividades humanas sobre os recursos hídricos, em especial as águas subterrâneas, tornou-se essencial para tomadas de decisão corretas e sustentáveis. O Aquífero Rio Claro, localizado no município homônimo, é um aquífero raso e livre, composto por um pacote pouco espesso e predominantemente arenoso da Formação Rio Claro. Possui água naturalmente de boa qualidade e grande parte deste reservatório estende-se sob a área urbana do município. Este estudo estima os impactos da seca de 2013/2014 e o potencial de explotação do aquífero através do uso de modelagem numérica. Para as simulações utilizou-se o método dos elementos finitos por meio do algoritmo Feflow. A porção norte da área, mais agrícola, compreende a principal área de recarga do aquífero, enquanto que a porção sul é mais urbanizada e apresenta um grau de impermeabilização maior, que impacta negativamente as taxas de recarga. O balanço de fluxo calculou uma perda de 5,3% da água do armazenamento do aquífero durante o período de seca, que representou, na região, uma precipitação quase 30% menor que a média histórica. A grande maioria dos poços cadastrados no município extrai água de aquíferos mais profundos, perfazendo cerca de 450 m³/h. Em um cenário no qual o Aquífero Rio Claro fosse responsável por toda essa demanda de água subterrânea durante todo o período de seca, o aquífero perderia cerca de 6,6% da água de seu armazenamento. O bombeamento dos poços atingiria aproximadamente 19% da recarga do aquífero, portanto, o aquífero tem potencial para comportar tal volume de explotação. No entanto, a concentração dos poços no distrito industrial e na área urbana do município representa um alto risco para o aquífero e para o abastecimento nestas áreas, com alteração da dinâmica de fluxo entre as porções norte e sul e interferência nas vazões dos poços.
Proper management of water resources is a key player in regional development, whether urban or agricultural. The knowledge about the impacts of climate changes and human activities on water resources, especially groundwater, it has become essential for making correct and sustainable decisions. The Rio Claro Aquifer, located in the homonymous city, is a shallow and unconfined aquifer, composed of a thin layer of Rio Claro Formation sandstones. It has good quality water in natural conditions and a significant part of this reservoir is located below the urban area. This study estimated the impacts of the drought of 2013-2014 and the potential exploitation of the aquifer using numerical modeling. Finite elements method by Feflow algorithm was used for the simulation. The northern portion, more agricultural, encompasses the main recharge area, while the southern portion is more urbanized and has a higher waterproofing coverage impacting negatively on the recharge rates. The water budget showed a loss of 5.3% of the aquifer storage during the dry season. The precipitation was almost 30% lower than the average in this region. The majority of registered wells in the city extracts water from deeper aquifers reaching about 450 m³/h. In a scenario in which the Rio Claro Aquifer is responsible for all groundwater demand throughout the dry season, the aquifer would lose about 6.6% of its water storage. The pumping wells reaches approximately 19% of the aquifer recharge, therefore the aquifer can support this exploitation volume. However, the spatial concentration of the wells in the industrial district and the urban area pose a high risk to the aquifer and the groundwater supply in these areas, by changing the water flow dynamics between the northern and southern portions and interference in the well rates.

Utilisée depuis des milliers d’années sous ses manifestations naturelles par l’Homme, cette ressource fait l’objet d’une exploitation commerciale depuis seulement le XXe siècle, à destination du chauffage de bâtiments, de certains usages industriels ainsi que de la production d’électricité. La France compte parmi les pionniers concernant l’usage direct de la chaleur alors qu’aucune filière industrielle n’est véritablement effective pour la production d’électricité d’origine géothermique. Le projet sélectionné, intitulé FONGEOSEC, a pour objectif la conception et la réalisation d’un démonstrateur innovant préindustriel d’une centrale géothermique haute enthalpie exploité par cogénération d’électricité et de chaleur. Un travail de recherche et développement, conduit par un consortium composé de partenaires industriels et scientifiques, vise au lancement de la filière industrielle géothermique haute température en France. L’objectif général des travaux de thèse porte sur une meilleure compréhension globale des comportements hydrauliques, massiques et thermiques des formations profondes en réponse à une sollicitation anthropique de longue durée. Il s’agit d’identifier les paramètres clés régissant la réponse du complexe réservoir à la suite d’une exploitation géothermique. Un point particulier sera consacré à caractériser la part de chacun des modes de transport de chaleur en milieu poreux – conduction thermique, convection libre et forcée – dans l’établissement des performances thermiques de l’ouvrage considéré. Plusieurs dispositifs techniques d’exploitation seront proposés afin de réduire les incertitudes associées au système géothermique souterrain et garantir le succès du projet FONGEOSEC. L’impact des mécanismes thermo-convectifs au voisinage des forages d’exploitation géothermique de grande profondeur reste peu documenté, a fortiori dans le cas de dispositifs déviés adoptant une complétion particulière. L’outil retenu pour l’évaluation des performances du dispositif au contact de l’encaissant est la modélisation numérique distribuée. La variabilité des propriétés physiques de l’hydrosystème, de la conception et des modalités d’exploitation du dispositif sur le comportement hydraulique et thermique de l’exploitation est envisagée selon différentes approches développées à partir de modèles numériques 3D
Used for thousands of years under its natural manifestations, this resource has been commercially exploited since the twentieth century, for the heating of buildings, certain industrial uses and the production of electricity. France is one of the pioneers in the direct use of heat, whereas no industrial cluster is truly effective for the production of geothermal electricity. The selected project, FONGEOSEC, aims to design and produce an innovative pre-industrial demonstrator of a high enthalpy geothermal power plant operated by cogeneration of electricity and heat. A research and development project, led by a consortium of industrial and scientific partners, aims to launch the high-temperature geothermal industrial sector in France. The general objective of this thesis is to improve the understanding of the hydraulic, mass and thermal behavior of deep porous formations in response to long-term anthropogenic stress. The aim is to identify the key parameters governing the response of the reservoir complex related to geothermal operation. A particular point will be devoted to characterize the part of each mode of transport of heat in porous medium – thermal conduction, free and forced convection – in the establishment of the thermal performances of the geothermal power plant. Several technical operating devices will be proposed to reduce the uncertainties associated with the underground geothermal system and guarantee the success of the FONGEOSEC project. The impact of thermo-convective mechanisms in the vicinity of deep geothermal borehole remains poorly documented, especially in the case of deviated wells with a complex inner geometry. The evaluation of the hydraulic and thermal performances of the device, based on 3D numerical modeling, is conducted according to different approaches

Le bassin hydrologique du Barada et de l’Awaj est le plus important et le plus intensément exploité de Syrie. Le sous bassin amont de la rivière Awaj occupe la partie sud-ouest de ce bassin. Dans cette région aride, l’eau souterraine représente la principale réserve et ressource de production d’eau. Dans l’optique de caractériser le fonctionnement du système hydrogéologique multicouche local et de calculer un bilan hydrologique pour l’aquifère superficiel, une méthodologie multi techniques couplant hydrochimie, isotopie et hydrodynamisme a été déployée. L’analyse détaillée des données hydrochimiques recueillies a mis en évidence la grande variabilité du fond géochimique local, directement fonction de la stratigraphie. Cette complexité stratigraphique induit une vision hydrogéologique complexe de nombreux corps aquifères. L’évolution de la chimie des eaux révèle la prépondérance du phénomène de dissolution/précipitation des roches carbonatées comme principal mécanisme de contrôle de l’hydrochimie, devant l’hydrolyse des silicates, la dissolution du gypse et l’échange ionique. En conséquence il n’a pas été possible de déduire de l’hydrochimie des eaux les preuves d’une recharge par drainance ascendante depuis l’aquifère du jurassique vers les aquifères superficiels, bien que la similarité des faciès hydrochimiques tend à consolider l’hypothèse d’une origine unique des eaux, sans toutefois permettre une identification des chemins d’écoulement. Les données isotopiques indiquent quant à elles, une infiltration importante et rapide des eaux météoritiques, avant qu’une importante phase d’évaporation n’ait lieu. Ainsi, l’important flux d’infiltration qui se produit essentiellement dans la partie montagneuse de la zone, représente la principale source de recharge du système aquifère multicouche régional. De ce fait la zone d’étude peut se subdiviser en deux sous régions : la première (A) se caractérise par une dissolution active et des flux de circulation d’eau souterraine fortement orientés verticalement vers la profondeur, alors que la seconde (B) est caractérisée par des écoulements peu profonds associés à des interactions hydrochimiques avec les roches encaissantes. Les résultats de la modélisation hydrodynamique du système mettent en évidence la connexion hydraulique entre l’aquifère profond du Jurassique et les aquifères surincombants par le biais d’une drainance ascendante. Le bilan hydrologique de l’aquifère se surface a ainsi pu être appréhendé : les principaux flux de recharge proviennent de l’infiltration des eaux météoritiques mais également de l’écoulement latéral du Jurassique dans la partie montagneuse. La drainance ascendante depuis le Jurassique dans la partie aval est également non négligeable. Du point de vue des sorties, le flux d’écoulement le plus important se situe en direction de l’est vers le centre du bassin. Ce constat permet de concevoir que La sous bassin amont de le rivière Awaj est la principale zone de recharge occidentale du bassin de Barada et Awaj
Barada and Awaj basin is the most important and extensively used water basin in Syria. The upper part of Awaj River occupies the southwestern part of this basin. In this arid region, groundwater is considered to be as a main source of water supply. In order to assess the main features which characterize the hydrogeological system in this area and calculate the water budget of the first aquifer horizon, a multi approach methodology using hydrochemistry, environmental stable isotopes and groundwater modeling were used as integrated tools. The detailed description of hydrogeochemical conditions has underlined the very complex variability of the stratigraphic sequences and hence the numerous hydrogeological units within the study area. Hydrogeochemical evolution reveals the domination of dissolution/precipitation of carbonate rocks as a main mechanism controlling groundwater chemical composition and to less extend, the silicate hydrolysis, dissolution of gypsum and reverse ion exchange. Consequently, hydrochemical patterns did not give enough evidences for the expecting of huge feeding flow from the Jurassic aquifers towards the Neogene/Quaternary aquifer. The similarity in water type tends to express the existence of a unique hydrochemical system where the individualised groundwater flow paths are difficult to delineate. The isotope compositions imply an important rapid infiltration of atmospheric precipitation before significant evaporation takes place. Hence the infiltrated precipitation provides the main source of groundwater recharge all over the study area and mainly throughout the mountainous parts. The study area can be dividing into two main sub-regions. The sub-region (A) which characterizes by active dissolution phenomena and deep vertical groundwater flow. And sub-region (B) which characterizes by a shallow horizontal flow component associated with active interaction between groundwater and hosting rocks. The result of groundwater model indicates a hydraulic connection between the deep aquifers and the overlying first aquifer through the upward leakage of groundwater. The components of the water budget of the first aquifer had determined. The lateral discharge from the Jurassic aquifer as well as the meteoric recharge is the most important recharging component of this budget. The upward leakage of groundwater from deeper aquifers also plays an important role. However, the lateral discharge from the eastern boundary is the largest discharge component which indicates that the study area can be considered as a main recharge region of the western side of the Barada and Awaj Basin

L’objectif est la construction numérique d’un modèle 3D régional de la plaine de Sidi Bouzid permettant la quantification du transfert hydrique et du rôle des crues sur le processus de recharge. Des simulations numériques de l’écoulement ont été réalisées à l’aide de Feflow et validées par des données mesurées in situ. Une conceptualisation des paramètres d’entrée a été réalisée afin de contourner l’absence de données mesurées. L'hétérogénéité de la zone non saturée a un impact significatif sur la variation du flux vertical et la propagation du front d’humidité. Les résultats obtenus en 1D ont été spatialisés à l’échelle de la plaine avec l’objectif de quantifier l’ensemble des flux d’écoulements. L’originalité réside, d’une part, dans la détermination des conditions aux limites appliquées à la surface du sol à partir des hydrogrammes des crues enregistrés et, d’autre part, au modèle conceptuel limitant l’évaporation. Le modèle hydrodynamique a mis en évidence que le bilan hydrique est fortement excédentaire. Les simulations de l’écoulement ont montré que l’approche des épandages de crues au niveau des périmètres surestime la recharge artificielle de la nappe
The aim of this study is to set up a 3D regional model to quantify water flux in unsaturated-saturated zones and the role of floods on the recharge process. Therefore, numerical flow simulations were conducted using the finite element Feflow that will be validated by measured data. A conceptualization of input parameters was carried out to overcome the absence of measured data. The heterogeneity of the vadose zone have a significant impact on the variation of the vertical flow, the residence time and the propagation of wetting front in the unsaturated zone. The results obtained in 1D were then used to quantify groundwater recharge of the entire area of the study site. The original approach is to derive the time-dependent hydraulic boundary condition of water level at the soil surface of the spreading perimeters by measured flood hydrographs and to develop a limited conceptual model of water uptake by evaporation. The hydrodynamic model showed that the water balance is very important. Flow simulations have shown that the perimeter flooding approach overestimates the artificial recharge of the aquifer

Nel lavoro di Tesi ci si è occupati dello studio delle sorgenti appenniniche di Mulino delle Vene, site a Carpineti, in Provincia di Reggio Emilia, e della modellazione dei deflussi sotterranei nell’acquifero fratturato che le alimenta. In particolare, sono state eseguite delle analisi idrologiche con l'obiettivo di quantificare la variazione di risorsa idrica nell'area in risposta al trend di variazione dell'uso del suolo. Successivamente si sono caratterizzate le sorgenti di Mulino delle Vene e l'acquifero che le alimeta per mezzo di analisi idrogeologiche. Infine, si è realizzato un modello numerico agli elementi finiti in grado di simulare i deflussi sotterranei nel periodo di scarico delle sorgenti e in assenza di ricarica.

Variable groundwater quality in complex aquifer-aquitard systems presents a challenge for sustainable groundwater development. In the Lower Murrumbidgee alluvial fan of the Murray-Darling Basin in semi arid inland Australia, shallow groundwater is saline (12000 µ S/cm) and locally contaminated by nitrate. Deep fresh aquifers (150 µ S/cm), developed as an irrigation water supply, were thought to be protected from downwards leakage by laterally extensive aquitards. However, hydrochemical sampling, augmented by historic data, revealed that aquifer salinisation (400 to 4000 µ S/cm) had occurred at some sites to 50 m depth since the mid 1980s. Aquitard windows, landscape depositional features at a scale of 10s to 100s of metres which are rarely detected by conventional investigations, were proposed as conduits for rapid downwards leakage in stressed systems. Intensive research was conducted at the Tubbo site where downhole geophysical logging and minimally disturbed cores were used to describe a saline clayey silt to 15m depth, an indurated clayey sand and 2 deep deposits of hard clayey silt. Fracturing was inferred by the scale dependency of aquitard permeability (Kv 10E-11 to 10E-6 m/s). Lithological variation near the surface was delineated by electrical imaging which revealed a 40m wide aquitard window beneath a veneer of smectite clay. Intensive monitoring of groundwater pressures in six piezometers (23-96 m depth) near the Tubbo irrigation bore and two other peizometers upgradient, indicated that the indurated clayey sand formed an effective hydraulic barrier but the deep silty deposits were spatially discontinuous. Groundwater samples were collected before, three times during, and after the 1998-99 irrigation season. A large, but delayed TDS increase occurred in the shallow aquifer and small pulses of saline water were sustained in the middle aquifer but shortlived in the deep aquifer. Hydrochemical and isotopic data dC-13, dH-2, dO-18, C-14 and H-3) showed the middle aquifer mixing with the deep aquifer, though retaining the signature of a palaeowater. Hydrochemical changes were accounted for with PHREEQC inverse mass balance models for the shallow aquifer. Mixing of aquifer water with 20-70% saline porewater from the upper aquitard occurred, together with ion exchange and NaCl dissolution. Based on an axisymmetric radial FEFLOW model, 5-30% of the volume pumped was accounted for by vertical leakage from the middle aquifer. Leakage from the shallow aquifer was small but significant, as it allowed high salinity water to migrate. Permeability and compressible storage measurements (Ss 10E-5 to 10E-4 /m) were used to constrain model calibration, and to show that direct mixing occurred mainly via aquitard windows at depth, and between the shallow and middle aquifers via leaky boreholes. Fracture flow and aquifer-aquitard interaction by diffusion were of secondary importance.

La modélisation hydraulique avec modèle déterministe est une méthode largement utilisée. Cependant,lamodélisation est un ptocessus complexe, notamrnent pour les aquifères où la quantité et la qualité desdonnées ne sont pas satisfaisantes. Etantune des sources pdncipales de I'eau douce dans la basse valléedu Var, Côte d',{.zur,Frarrce,la nappe libre de lavallée est menacée parla pénurie et la pollution. Maþéle grand nombre d'études effectuées dans cette zone, la dynamique des écoulements souterrains esttoujours patiellement inconnue. Par conséquent, la métropole Nice Côte d'Azur a besoin de développerun système d'aide à la décision (SÂD) à base des modèles numériques afin d'assurer une gestion plusefficace de l'eau souteraine. Un modèle numérique est développé avec FEFLO\ø en tenant compte desprécipitations, de l'é:vapoftanspiration, du pompage de l'eau souterraine, et des échanges nappe-rivière.Le volume d'eau pompée pour l'usage agdcole et le taux d'échange du lit mineur du Var ont été calibrés.Le modèle a été. vabdé. par une simulation de '1.266 jours. Le modèle est utilisé pour simuler les scénatüdes événements d'inondation et de sécheresse, les scénadi de pollution et l'intrusion d'eau de mer dans lavallée. Une première conception du système d'aide à la décision est présentée comme le demier exemplede l'application du modèle. Une interface de couplage est développée en Java et sert à échanger lesdonnées entre le modèle souterrain et le modèle à surface libre élaboré avec MIKE21FM
Groundwater modeling with deterministic model is a complicated process, especially in complex aquiferswhere the quantity and the quality of the measuted data arc not satisfying. The unconfined alluvialaquifet is the main water resource in the lower valley of Vat river, Ftench Riviera, but it faces a thteat ofshortage and pollution. Despite numerous previous studies, the dynamics of the gtoundwater flow in thealluvial aquifer and the characteristics of the rivet-aquifer exchanges ¿re s':ll partially unknown.Therefore the local u/ater management service requires a decision support system PSS) based onnumerical models to ensure a better groundwater management. A hydraulic model is set up withFEFLO!ø software by considedng ptecþitation, evâpotranspiration, gtoundwatet exftacdon and rivetaquiferexchanges. The non-documented groundwater exttaction fot agticultural use and the transferrates in the dverbed along the river have been calibtated. The model has been validated with asimulation of 7266 days. The model is applied to simulate the scenarios of flood and drought events, thepollution events in the unconfined aquifer in the valley and the seawater inrusion in the estuary of Yarriver. These case studies contributes to increase the knowledge of the aquifet. A fust conception of theDSS tool is presented as the last example of model application. A coupling interface is developed thanksto aJava which enables an automatic exchange of data between the groundwater flow model and thesurface wâter flow model built with MII(E2ltr}'/. More tests should be done to validate the couplinginterface

Située au Nord-Ouest de la Tunisie centrale, le bassin de Foussana du gouvernorat de Kasserine constitue une zone de transition entre la région tellienne pluvieuse au Nord et la région saharienne au Sud. Il est bordé par une série de reliefs de formes et de directions variées. Dans cette région aride à semi-aride, l’eau souterraine représente la principale réserve et ressource de production d’eau. Du point de vue tectonique, le bassin de Foussana est caractérisé par la présence de multiples failles. Les failles de direction NW-SE, dont la plus importante est celle qui s’aligne parallèlement à l’Oued Hatab (Faille de Foussana). Les failles qui bordent le fossé du côté est et du côté Ouest se placent dans la famille directionnelle NW-SE. Les failles de direction NE-SW, dont la plus importante est celle qui borde Jebel Chambi du côté sud, montrent une activité décrochante senestre à composante normale. Les failles de direction EW constituent la troisième famille de fracture ayant contrôlé l’évolution de cette structure effondrée. Le bassin d’effondrement de Foussana formé par le jeu de failles de direction NW-SE constitue une fosse subsidente comblée de dépôts MioPlioQuaternaires à caractère continental et renferment plusieurs niveaux aquifères avec des intercommunications latérales entre les grés miocènes et les niveaux Plio-Quaternaires le long des failles de bordure et par drainance le long de l’axe de la fosse matérialisé par l’oued El Hatab. Le Quaternaire couvre toute la cuvette. Sa constitution varie selon les régions, en bordure, nous retrouvons les éboulis de pente formés de gros éléments de calcaire sub- arrondis, parfois bien cimentés par de l’argile rouge. Ces dépôts laissent la place au centre de la cuvette de l’Oued Hatab à des dépôts plus fins constitués de sol sableux ou argilo - sableux avec une certaine proportion de limon. Dans les régions de bordure, les dépôts du PlioQuaternaire très grossiers sont directement superposés aux grès miocènes. Les aquifères profond du Pliocène (PQ2) et superficiel du Quaternaires (PQ1) sont susceptibles de constituer un aquifère unique, puisque leurs résistivités sont presque semblables, leurs salinités sont voisines, et leurs piézométries sont confondues. Les grès Miocènes varient d’une région à l’autre selon qu’on est dans les zones de bordures ou dans des fosses. Ils sont libres au Nord et au Sud de la plaine séparés par les deux grands accidents tectoniques. Les grès en affleurement sont non seulement plus grossiers mais aussi plus homogènes, ce qui attribue aux aquifères libres une grande perméabilité, contrairement aux aquifères des grès en charge où les alternances fréquentes d’argiles et de marnes réduisent énormément ce paramètre. Cette homogénéité croit également en profondeur. Dans l’optique de caractériser le fonctionnement du système hydrogéologique multicouche et de calculer un bilan hydrologique pour le système aquifère, une méthodologie multi techniques couplant l’ hydrochimie, l’isotopie et l’hydrodynamisme a été déployée. L’analyse détaillée des données hydrochimiques recueillies a mis en évidence la grande variabilité du fond géochimique local, directement fonction de la stratigraphie. Cette complexité stratigraphique induit une vision hydrogéologique complexe de nombreux corps aquifères. L’évolution de la chimie des eaux révèle la prépondérance du phénomène de dissolution des minéraux évaporitiques et la précipitation de la calcite comme principal mécanisme de contrôle de l’hydrochimie devant les phénomènes d’échange de base et par la pollution anthropique induit par la présence des nitrates. En conséquence il n’a pas été possible de déduire de l’hydrochimie des eaux les preuves d’une recharge par drainance ascendante depuis l’aquifère du Miocene vers les aquifères superficiels, bien que la similarité des faciès hydrochimiques tend à consolider l’hypothèse d’une origine unique des eaux, sans toutefois permettre une identification des chemins d’écoulement
The study area lies in the northern part of central Tunisia and extends over about 650 km2. It is located betweenthe rainy Tellian region in the North and the Saharan region in the South. The Foussana Basin is a typical closedinland basin surrounded by high mountains where the precipitation varies over space and time as a result oftopography and seasonality.The main outcrop that marks the watershed of Foussana basin is the quaternary alluvium, which is surrounded byCretaceous reef of deposits covering folds Mountains bounding. The Foussana basin is composed of two aquifers,the PlioQuaternary and the Miocene aquifers. The PlioQuaternary aquifer consists of clayey sand, coarse sand andsandstone deposits. This aquifer is composed of two permeable levels PlioQuaternary Aquifer (PQ1) and PlioceneAquifer (PQ2), which are separated by interbedded sandy marl. The Miocene aquifer consists of sandstone andcoarse sands. This aquifer constitutes an important water source in the study area because of its relativelysignificant thickness and its water quality. It‘s separated to the PlioQuaternary aquifer by a clay layer. The differentaquifers communicate through faults.The groundwater flows occurs from the borders to the center of the basin,i.e. from the surrounding hills to the depression area. The main source of aquifer recharge is infiltration of rainfalland dam water.Groundwater samples with low TDS values, which typically correspond to outcrops of the Miocene aquifer andsome samples of the first PlioQuaternary aquifer PQ1, are typically of SO4-Ca-HCO3-Na water type. In contrast,groundwater samples with high TDS values, most of which were collected in the PlioQuaternary aquifer (PQ1 andPQ2) and groundwater of the Confined Miocene, are typically of SO4-Ca-Na-Mg water type. The main sources ofthe water mineralization in the Foussana basin are the water-rock interaction processes i.e. dissolution ofevaporates and cation-exchange process.The isotopic signatures permit to classify the studied groundwaters into different groups. The PlioQuaternaryaquifer groundwater was classified into two groups. These are the non-evaporated groundwater, which ischaracterized by depleted δ18O and δ2H contents highlighting the importance of modern recharge at higher altitude,and the mixing process with the deep aquifer of the Miocene. The evaporated groundwater that exhibits enrichedstable isotope contents, these enriched values could be related to the evaporation process, which occurs possiblyin the upper part of the unsaturated zone of the PlioQuaternary aquifer (depression area).The Miocene aquifersgroundwaters are classified into two groups. The first group is characterized by relatively depleted isotope contentscorresponding to outcropping Miocene in the border indicating the altitude effect. The second group isdistinguished by relatively depleted contents of stable isotopes corresponding to the confined Miocene reflectinga palaeoclimatic origin. Tritium data permit to identify recent groundwaters originating from a mixture ofcontemporaneous and post-nuclear recharge; and ancient groundwaters deriving from pre-nuclear recharge.Radiocarbon activities decrease from 80 pmc in the recharge area to less than 3 pmc in the confined aquiferproviding ages from present day to 30 000 years BP.In conclusion, a conceptual model has been produced to describe the functioning of the aquifers. The modelling isused as a tool to synthesise the data and the functioning hypothesis. It gives a visualization mean and can put inevidence the aspects, which should be deepened in next works

The Ground Source Heat Pump (GSHP) is a promising technology for the heating and cooling of buildings with renewable energy sources. Borehole Heat Exchangers, in which heat is exchanged by circulating a heat carrier fluid into a pipe closed loop, are the most used typology. The energy performances of these plants depend from the properties of the BHE and of the soil. In this work, the operation of BHE for a period of 30 years has been simulated, using a finite-element subsurface flow and heat transport modelling code (FEFLOW). The relative influence of each BHE, hydrogeological and thermal soil property has been investigated, running a set of simulations and analyzing the resulting fluid temperatures in the closed loop to estimate the heat pump energy consumption. Comparing the results, we observe that the length is the most important BHE property, and it should be optimized in order to minimize the overall expense (installation and maintenance); also the pipe distance, the grout heat conductivity and the properties of the heat carrier fluid play an important role. The soil heat conductivity heavily influences the resulting fluid temperatures, and in-situ tests should be carried to predict the plant operation accurately. The presence of subsurface flow enhances the heat transfer in the subsoil, improving the heat pump performances. The heat dispersivity spatial dependence is still unknown, and this causes a strong uncertainty in the prediction of BHE operation in presence of groundwater flow.

This article addresses one of the main problems faced by small- and medium-sized business in the non-metallic mining sector in Peru. These companies own warehouses and face the major problem of failing to deliver orders correctly and in a timely manner. This problem usually occurs when the business grows from a small- to medium-sized company in a short span of time; this situation leads to new processes within warehouses that are mostly not standardized. Besides, facilities are no longer optimal in space and the workers are not properly trained. The case study shows that the orders were not delivered on time due to factors such as lack of product identification, although the products have an expiration date and a warehouse without signaling and surrounded by traffic. To tackle this situation, a labeling process has been designed for the products, an adequate distribution technique is used in the warehouse through a newly designed warehouse layout, and a First Expired, First Out system has been implemented. Similarly, the design is accompanied by the 5s tool to provide a basis for order and continuous improvement. The results show that deliveries with delays were reduced from 38% to 10%. These results show that companies can grow rapidly and maintain quality of service through orderly management.

El presente trabajo de investigación tiene como objetivo reducir el índice de devoluciones de una empresa de consumo masivo. Se aplicó la metodología Lean Warehousing y la herramienta VRP para plantear una solución al problema. El proyecto se divide en cuatro capítulos. En el primer capítulo se desarrolla los conceptos y bases teóricas en las que se fundamenta la propuesta. El segundo capítulo presenta el entorno de la empresa, los procesos realizados y los roles que desempeñan cada uno de los trabajadores. También, se identifica el problema a resolver, para ello se requirió utilizar como herramienta el árbol de decisiones para identificar las causas raíz, las cuales son explicadas y fundamentadas. El tercer capítulo plantea 2 metodologías que ayudarán a resolver las 4 causas principales. La primera metodología consiste en determinar la ruta de transporte óptima y la segunda metodología plantea mejorar el abastecimiento y control de productos dentro del almacén. Finalmente, se presenta los costos de la implementación y los beneficios que se obtendrían con la implementación de las propuestas. Por último, el cuarto capítulo se expone los resultados de la implementación con la finalidad de reducir el índice de devoluciones. Así como, la reflexión del proyecto y las recomendaciones para futuras investigaciones.
This research work aims to reduce the rate of returns of a mass consumption company. The Lean Warehousing methodology and the VRP tool were applied to propose a solution to the problem. The project is divided into four chapters. In the first chapter the theoretical concepts and bases on which the proposal is based are developed. The second chapter presents the company's environment, the processes performed and the roles that each of the workers play. Also, the problem to be solved is identified, for this it was required to use the decision tree as a tool to identify the root causes, which are explained and substantiated. The third chapter presents 2 methods to help resolve the 4 main causes. The first methodology consists in determining the optimal transport route and the second methodology proposes to improve the supply and control of products within the warehouse. Finally, the implementation costs and the benefits that would be obtained with the implementation of the proposals are presented. Finally, the fourth chapter describes the results of the implementation in order to reduce the rate of returns. As well as, the reflection of the project and the recommendations for future research.
Trabajo de Suficiencia Profesional

O município do Barreiro é autossustentável no abastecimento de água, que extrai exclusivamente de captações subterrâneas. As necessidades hídricas para consumo humano, indústria e agricultura são correspondidas com recurso à elevada disponibilidade do sistema aquífero da Bacia do Tejo-Sado. Neste concelho, existe conexão hidráulica entre o aquífero e as águas do Tejo, estando este sujeito a fenómenos de intrusão salina na frente ribeirinha. A sobre-exploração agrava o problema e aumenta a vulnerabilidade, constituindo uma forte ameaça à sustentabilidade hídrica da região. A área em estudo, intervencionada por obras hidráulicas e pressupondo o alargamento do Porto de Lisboa, poderá sofrer alterações no equilíbrio químico e hidrodinâmico do meio subterrâneo e substanciais avanços na cunha salina. O aquífero Mio-Pliocénico, no setor norte do Barreiro, é um sistema multicamada complexo, constituído, essencialmente por um aquífero superficial livre e outro confinado mais profundo, separados por um aquitardo. A exploração incide principalmente no aquífero confinado, nos níveis detríticos com carbonatos do Miocénico Marinho. Os níveis piezométricos neste aquífero estão rebaixados em relação ao estuário, em consequência dos caudais extraídos na frente ribeirinha para abastecimento do complexo industrial. O regime de exploração intensivo promove drenância vertical no sentido descendente, transferindo-se águas de menor qualidade para o aquífero confinado. O modelo numérico de fluxo subterrâneo desenvolvido para a frente ribeirinha revela uma forte zona de depressão no aquífero confinado, donde grande parte dos volumes captados deriva das camadas subjacentes ao estuário do Tejo, ainda que confinadas por níveis menos permeáveis. As linhas de fluxo regressivas calculadas para as captações F88 e F97 comprovam esta origem. As simulações efetuadas pelo FEFLOW mostram ligeiros cones de rebaixamento localizados no aquífero livre e inversão no sentido natural da drenância, dos níveis superiores para o aquífero confinado, agravando a elevada vulnerabilidade do sistema à intrusão salina reconhecida neste local.

Groundwater represents the largest supply of drinking water in the world (25-40%). Increasing urban development and increasing industrial activities, growing water demand due to climate change, and the consequent increase in urban runoff volumes due to the presence of sealed surfaces are causing ad-verse effects on groundwater both quantitatively and qualitatively. To address water stress, Managed Aquifer Recharge (MAR) represents an engineered ap-proach to water security. MAR techniques aim to recharge the aquifer under controlled conditions for the purpose of subsequent recovery or as a barrier to prevent seawater intrusion. The reuse of urban water to implement this strate-gy is adopted from the perspective of environmental sustainability. However, the presence of residual contaminants in the injected stream challenges the feasibility of this solution because it may affect human health. In this context, the site modeled in the present work is located adjacent to the municipality of Avetrana, a place in which a confluence will be built from a channel in order to collect stormwater and floodwater thus protecting the town. The case study has a high level of hydraulic disturbance that makes it necessary to evaluate the vulnerability to pollution of the karst aquifer, which is characterized by a low anti-pollution capacity and therefore very fragile. As a result, it was necessary to perform a numerical simulation of groundwater flow and mass transport in the affected area. FEFLOW software, based on the finite element method, was used to determine the three-dimensional numerical groundwater model. The groundwater flow field was obtained by inputting boundary conditions and pa-rameters derived from hydrogeological field surveys and literature review. Spe-cifically, the methodology involved developing the conceptual hydrogeologic model of the aquifer and then modeling the mass transport of a hypothetical contaminant under different scenarios. Considering that the input conditions in the transport model represent ex-treme and occasional situations, the modeling performed showed that the geo-logic structure represents a potential barrier to pollution. To sum up, the purpose of this study was to make the model a good approx-imation of the groundwater system and to provide reference to prevent pollu-tion in karst aquifers.

In this master's thesis, a numerical model of groundwater flow in a contaminated area of Hradec Králové was created. After that, a circulation well was introduced. Two circulation well variants, which differ in the amount of pumped water, were examined. All simulations were performed with the aid of a finite element solver Feflow 5.2. The values of hydraulic head resulting from the mathematical model are in a good agreement with those obtained from the field measurement. The groundwater flow present in the area of interest exhibits south to southwest direction. After introducing the circulation well, I focused on the influence of the amount of pumped water on the groundwater flow. The outcome of this observation was that during the higher volume pumping, the circulation cell is larger and therefore has a higher influence on the groundwater flow. I evaluated that it is more efficient to pump a higher amount of water in the investigated area.