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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
71

Assinaturas geoelétricas em área contaminada por hidrocarboneto no pólo industrial de Cubatão - SP /

Baessa, Marcus Paulus Martins. January 2007 (has links)
Orientador: Chang Hung Kiang / Banca: Walter Malagutti Filho / Banca: Vagner Roberto Elis / Resumo: Visando caracterizar assinaturas geoelétricas em áreas contaminadas por hidrocarbonetos de petróleo, foram realizados levantamentos geofísicos utilizando-se os métodos da eletrorresistividade e análises hidroquímicas em área localizada no Pólo Industrial de Cubatão - SP. Foram realizadas 19 sondagens elétricas verticais (SEVs), 4 imageamentos elétricos 2D e 3 imageamentos elétricos 3D, tendo sido identificadas, por meio destas técnicas, 12, 21 e 9 anomalias, respectivamente. Constatou-se que a presença de anomalias condutivas na zona não saturada coincide com a ocorrência de fase livre nos poços de monitoramento. A identificação de NH4 +, subjacente à ocorrência de fase livre, confirmou a atuação de processo de denitrificação. As baixas concentrações dos íons sulfato (SO4 2-) e ferroso (Fe2+) indicam que os mesmos foram reduzidos biologicamente para sulfeto (S2-) e precipitado como sulfeto de ferro (FeS), respectivamente. Esses resultados permitem concluir que as anomalias condutivas estão diretamente associadas à presença de fase residual de hidrocarbonetos, em processo de biodegradação, na zona não saturada. Desta forma, os métodos de investigação geofísica utilizados permitiram identificar áreas sob influência de hidrocarbonetos de petróleo. / Abstract: Geophysical surveys using electroresistivity methods and hydrochemical analyses were applied aiming the characterization of geoelectrical signatures in hydrocarbon contaminated sites located in the Polo Industrial de Cubatão - SP. There have been accomplished nineteen vertical electric soundings (VESs), four 2D and three 3D electrical imaging, which identified 12, 21 and 9 geophysical anomalies respectively. It was verified that the presence of conductive anomalies within the non-saturated zone coincided with the occurrence of free phase on the monitoring wells. Ammonium (NH4 +) identification, underlying the free phase occurrence, reinforced the activity of denitrifying process. Additionally, low concentration values of sulfate (SO4 2-) and ferrous (Fe2+) ions indicated that they were, respectively, biologically reduced to sulfide (S2-) and precipitated as iron sulfide (FeS). Based on those results, it was concluded that the conductive anomalies detected inside the non-saturated zone were directly associated with the presence of hydrocarbon residual phase, with was undergoing a biodegradation process. Therefore, the geophysical methods applied in this study allowed the identification of sites under petroleum hydrocarbons influence. / Mestre
72

Avaliação da qualidade da água subterrânea de poços ponteira no município de Osório, RS

Paim, Rosana Alves January 2018 (has links)
Este trabalho buscou avaliar a qualidade da água subterrânea de poços ponteira, que captam água do Sistema Aquífero Quaternário Costeiro (SAQC) na região de Osório (RS), através da aplicação de diferentes métodos. Para a realização do estudo foi feito um inventário e cadastramento de poços, o levantamento e interpretação de dados geológicos e hidrogeológicos, além da coleta e análise de amostras de água. Para este trabalho foram utilizados dados físico-químicos e bacteriológicos, obtidos através das análises de água (campo e laboratório), que foram coletadas em 26 poços. A avaliação dos resultados foi realizada através dos diagramas de Piper e Stiff, da comparação com os Valores Máximos Permitidos (VMP) em portarias de potabilidade e da aplicação de métodos de avaliação da qualidade da água e risco a saúde. Os resultados obtidos permitiram evidenciar que no município, a principal forma de captação da água subterrânea, ocorre por meio de poços ponteira que possuem profundidades na sua maioria, inferiores a 20 metros e que captam água de aquíferos granulares livres associados a camadas de sedimentos arenosos. Além disso, a maior parte das águas subterrâneas apresentaram valores de pH entre 5,6 e 6,5 e valores de condutividade elétrica (CE) entre 0 a 200 uS/cm. As concentrações de nitrato variaram entre 0 e 2 mg/L N-NO3, de cloretos e sódio não ultrapassam 30 mg/L, os sólidos totais dissolvidos entre 0 e 200 mg/L, indicando a ocorrência de águas doces com baixa mineralização. Os resultados das análises bacteriológicas indicaram a presença de Escherichia coli e coliformes totais. A comparação dos resultados das análises com os VMP da portaria do Ministério da Saúde Nº 2914/11 (Brasil, 2011), indicaram a ocorrência de poços que apresentam alterações nos parâmetros pH, amônia, ferro, cor, manganês, turbidez, bem como presença de Coliformes Totais e E.coli. Com o uso do Índice de Qualidade da Água Subterrânea (IQUAS), foram classificadas amostras de água como ótimas, boas e péssimas. Já o cálculo do Índice Relativo de Risco (IRR) evidenciou a ocorrência de amostras que apresentaram valores altos, a Avaliação de Risco à Saúde, indicou a ocorrência de amostras que apresentaram Risco não Carcinogênico. Por fim a partir deste estudo pode-se verificar que o uso de diferentes métodos para avaliação da qualidade da água, tem grande importância, pois torna mais consistente essa avaliação, já que cada método envolve a análise de diferentes parâmetros. / The aim objective of this work was to evaluate the groundwater quality of wells, which capture water from the Coastal Quaternary Aquifer System (SAQC) in the region of Osorio (RS), by applying different methods. In order to carry out the study, an inventory and registration of wells, the survey and interpretation of geological and hydrogeological data, as well as the collection and analysis of water samples. For this work, physicochemical and bacteriological data were obtained through water analysis (field and laboratory), which were collected in 26 wells. The evaluation of the results was carried out through the Piper and Stiff diagrams, the comparison with the Maximum Permitted Values (VMP) in potable water consumption and the application of water quality and health risk assessment methods. The results obtained showed that in the municipality, the main way of captation of groundwater occurs through pointer wells that have a depth of less than 20 meters and capture water from unconfined granular aquifers associated with layers of sandy sediments. In addition, most groundwater had pH values between 5.6 and 6.5 and values of electrical conductivity (EC) between 0 and 200 uS/cm. Nitrate concentrations ranged from 0 to 2 mg / L NNO3, with sodium chloride not exceeding 30 mg/L, total solids dissolved between 0 and 200 mg/L, indicating the occurrence of fresh water with low mineralization. The results of the bacteriological analyzes indicated the presence of Escherichia coli and total coliforms in 4 wells. The comparison of the results of the analyzes with the MPV of Ministry of Health No. 2914/11 (Brazil, 2011) indicated the occurrence of wells that present alterations in pH, ammonia, iron, color, manganese, turbidity and presence of Total Coliforms and E. coli. With the use of the Underwater Water Quality Index (IQUAS), 9 water samples were classified as optimal, 2 as good and 4 bad. The calculation of the Risk Index (IRR) evidenced the occurrence of 7 samples that presented high values, the Health Risk Assessment, indicating the occurrence of 2 samples that presented non-Carcinogenic Risk. Finally, from this study we can verify that the use of different methods to evaluate water quality, is of great importance, since it makes this evaluation more consistent, since each method involves the analysis of different parameters.
73

Variação espaço-temporal no material inorgânico dissolvido na Bacia Amazônica

Sánchez, Liz Stefanny Hildalgo 21 February 2014 (has links)
Submitted by Geyciane Santos (geyciane_thamires@hotmail.com) on 2015-10-21T14:31:52Z No. of bitstreams: 1 Dissertação - Liz Stefanny Hidalgo Sánchez.pdf: 8247336 bytes, checksum: 63ac2a1d6ab16326024e81d93ab233d6 (MD5) / Approved for entry into archive by Divisão de Documentação/BC Biblioteca Central (ddbc@ufam.edu.br) on 2015-10-22T19:08:07Z (GMT) No. of bitstreams: 1 Dissertação - Liz Stefanny Hidalgo Sánchez.pdf: 8247336 bytes, checksum: 63ac2a1d6ab16326024e81d93ab233d6 (MD5) / Approved for entry into archive by Divisão de Documentação/BC Biblioteca Central (ddbc@ufam.edu.br) on 2015-10-22T19:06:01Z (GMT) No. of bitstreams: 1 Dissertação - Liz Stefanny Hidalgo Sánchez.pdf: 8247336 bytes, checksum: 63ac2a1d6ab16326024e81d93ab233d6 (MD5) / Approved for entry into archive by Divisão de Documentação/BC Biblioteca Central (ddbc@ufam.edu.br) on 2015-10-22T19:14:15Z (GMT) No. of bitstreams: 1 Dissertação - Liz Stefanny Hidalgo Sánchez.pdf: 8247336 bytes, checksum: 63ac2a1d6ab16326024e81d93ab233d6 (MD5) / Made available in DSpace on 2015-10-22T19:14:15Z (GMT). No. of bitstreams: 1 Dissertação - Liz Stefanny Hidalgo Sánchez.pdf: 8247336 bytes, checksum: 63ac2a1d6ab16326024e81d93ab233d6 (MD5) Previous issue date: 2014-02-21 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The current work studies the space-time variety of dissolved inorganic material (Ca2+, Na+, K+, Mg2+, Cl-, SO4 -2, HCO3 - e SiO2) in 6 hydrological stations of the ORE-HYBAm network, which is located in the Amazon basin (Tabatinga-Nazareth, Manacapuru and Óbidos in the Solimões-Amazonas river; Porto Velho and Borba-Fazenda Vista Alegre in the Madeira river; and Lábrea in the Purús river). In the Solimões-Amazonas river, concentrations of Ca2+, Mg2+, HCO3 - e SO4 -2 have heterogeneous distribution and do not exhibit seasonality; because of the correlation among their concentrations, it is suggested that they own similar mobilization dynamic. This correlation is also observed between the Madeira and Purús rivers. However, in these rivers, the mentioned ions show seasonal chemical variability and reversely proportional to caudal (dilution-concentration effect). This behavior is observed to Cl- and Na+ in the stations of the Solimões -Amazonas y Madeira rivers, which means the liberation of an almost constant flow during the hydrological cycle. Meanwhile, K+ and SiO2 own constant concentrations along the years and among the stations, indicating that their flows are dependent on the caudal. It also can be identified that in the distribution of flows of Ca2+, Mg2+, HCO3 and SO4 -2, in the Solimões-Amazonas river, hydroclimatic factors as well as the heterogeneity of the sources (ex. carbonates, silicates) are involved. In the Madeira and Purus rivers there is less influence of these factors, which indicates greater contribution of the silicates with weathering slower than carbonates. Therefore, the geology and hydroclimatic factors influence in the distribution of the flows of dissolved inorganic material in the Amazon basin. But as the Solimões basin contributes approximately 84% of the total flux of dissolved materials in the basin and is under hydroclimatic factors influence, one can say that the temporal variability of this factor controls the temporal flows of dissolved material in the Amazon basin. This research has importance to the understanding of the geochemical process in the Amazon basin, as well as to provide a basis to future studies. / O presente trabalho estuda a variabilidade espaço-temporal da composição química do material inorgânico dissolvido (Ca2+, Na+, K+, Mg2+, Cl-, SO4 -2, HCO3 - e SiO2) nas águas de seis estações hidrológicas da rede ORE-HYBAM na bacia Amazônica (Tabatinga- Nazareth, Manacapuru e Óbidos no rio Solimões Amazonas; Porto Velho e Borba-Fazenda Vista Alegre no rio Madeira e Lábrea no rio Purus). Nas estações do rio Solimões e Amazonas as concentrações de Ca2+, Mg2+, HCO3 - e SO4 -2, têm distribuição heterogênea ao longo dos oito anos estudados e não apresentam sazonalidade. Entretanto nas estações do rio Madeira esses íons mostram variabilidade química sazonal e inversamente proporcional à vazão (efeito diluição-concentração). Este mesmo comportamento é observado para Cl- e Na+ nas estações do rio Solimões-Amazonas e Madeira o que indica a liberação de um fluxo quase constante ao longo do ciclo hidrológico. K+ e SiO2, apresentam concentrações quase constantes ao longo dos anos e entre as estações, indicando que seus fluxos dependem da variabilidade da vazão. Identifica-se também que na distribuição dos fluxos de Ca2+, Mg2+, HCO3 - e SO4 -2 nas estações do rio Solimões e Amazonas intervém tanto fatores hidrológicosclimáticos como a heterogeneidade das fontes (ex. carbonatos, silicatos). No Madeira e Purus, há menor influência destes fatores, o que evidencia maior aporte dos silicatos com intemperismo mais lento que os carbonatos. Portanto, a geologia e os fatores hidroclimáticos influenciam a distribuição dos fluxos de material dissolvido. Porém como a bacia do Solimões aporta aproximadamente 84% do fluxo total de material dissolvido na bacia e está sob influência, principalmente do fator hidroclimático, pode-se dizer que a variabilidade temporal desse fator controla a temporalidade dos fluxos de material dissolvido na bacia amazônica. Este estudo tem importância para o entendimento do processo geoquímico na bacia amazônica, além de servir de linha base para futuros estudos.
74

Variable Specific Discharge and Its Influence on Mass Export of Carbon, Sulphur, Calcium and Magnesium in a Boreal Forest Catchment / Variabel specifik avrinning och dess påverkan på exporten av kol, svavel, kalcium och magnesium från ett avrinningområde i barrskogsbältet

Gärtner, Isabell January 2016 (has links)
Considerable research efforts are made in order to understand the global carbon cycle and how it will affect future climate change and vice versa. To be able to calculate the export of carbon from a certain area, discharge is one of the most important variables together with stream concentrations. Measuring discharge in every catchment would be impossible, as it is both time consuming and expensive. To come around these obstacles, the majority of studies on element export use known discharge data from gauging stations at a single catchment outlet and assumes the same discharge per unit area from nearby catchments, known as the assumption of uniform specific discharge. A few studies in recent years, have come to the conclusion that this questionable assumption can lead to large errors in estimated discharge volumes and it should therefore be reconsidered.This study aims to analyse how the export of elements changes if actual measured variable discharge is applied in comparison to uniform specific discharge. The results of this study shows that the assumption of uniform discharge leads to an overestimation of the export of dissolved organic carbon (DOC), sulphur, calcium and magnesium from forest-dominated catchments by up to 30%. At the same time this assumption leads to an underestimation of export from wetland-dominated catchments by up to 26% over a five year period. / Mycket av forskningen de senaste åren har handlat om framtida klimatförändringar och det globala kolkretsloppet och hur de båda påverkar varandra. För att göra tillförlitliga beräkningar av hur mycket kol ett område, i det här fallet ett barrskogsområde i norra Sverige, tillför vattendragen i närheten under en viss tid skulle det behöva göras vattenståndsmätningar och vattenanalyser vid varje vattendrag, men det skulle vara omöjligt eftersom det är för kostsamt och tidskrävande. För att ändå kunna göra uppskattningar av hur mycket kol, spårämnen och metaller som kommer från ett område, använder de flesta studier information om vattenstånd och ämneskoncentrationen i vattnet från mätningsstationer vid avrinningsområdets utlopp. Samma uppgifter används för att göra beräkningar för det stora området, som för mindre delområden i det. Under de senaste åren har ett antal studier kommit fram till att användandet av data som inte har tagits i direkt anslutning till ett avrinningsområde kan leda till stora fel och kanske borde undvikas.Den här uppsatsen har som syfte att analysera vilka skillnader som uppstår när avrinningsdata från olika delområden används istället för samma data för alla områden. Resultatet av denna studie visar att om man använder samma data för alla områden leder det till att exporten av kol, svavel, kalcium och magnesium från huvudsakligen skogsklädda områden överskattas med upp till 30% och underskattas från områden med mycket våtmarker med upp till 26%.
75

Quantification de la recharge naturelle et artificielle d'un système aquifère soumis à des contraintes climatiques et anthropiques en zone semi-aride (bassin de Sbiba et Foussana) Tunisie centrale / Quantification of natural and artificial recharge of an aquifer system subject to climatic and anthropogenic activities in semi-arid zone ( Foussana basin)

Hachaichi, Zohra 21 February 2017 (has links)
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.
76

Caractérisation du fonctionnement de la zone non saturée des aquifères karstiques : Approche directe par études hydrodynamiques et hydrochimiques sur le Bassin de Recherche, d'Expérimentation et d'Observation de Fontaine de Vaucluse – Laboratoire Souterrain à Bas Bruit de Rustrel – Pays d’Apt / Functioning of karst aquifers unsaturated zone : Direct hydrodynamic and hydrochemical studies, Fontaine de Vaucluse – Laboratoire Souterrain à Bas Bruit de Rustrel – Pays d’Apt Research, Experimentation and Observation karst watershed

Barbel-Périneau, Aurore 13 September 2013 (has links)
La première étude du fonctionnement de la zone non saturée (ZNS) des aquifères karstiques, par accès direct, a été réalisée dans la galerie souterraine du LSBB, sur le bassin expérimental de la Fontaine de Vaucluse. Cette galerie recoupe arbitrairement le réseau karstique et les écoulements de la ZNS. Ceux-ci sont répartis tout au long de la galerie sous différentes épaisseurs de roche calcaire (de 30 à 514 m). 45 points d’écoulements ont été prélevés au moins une fois. Les suivis hydrodynamiques et hydrochimiques sur 8 ans montrent : (i) l’organisation des écoulements en fonction de la profondeur et de la densité de fracturation, (ii) les modalités de réponses hydrodynamiques et hydrochimiques des écoulements en fonction des précipitations et de l’état initial du système, (iii) la nécessité de prendre en compte la non-linéarité des réponses impulsionnelles dans la modélisation.Trois composantes d’écoulement sont caractérisées : (i) une composante lente, pérenne et caractérisée par des longs temps de séjour, (ii) une composante rapide, active seulement en période de très forte recharge, marquée par les traceurs d’infiltration et caractérisée par de faibles temps de séjour, (iii) une composante intermédiaire, associée à des comportements hystérétiques, également marquée par les traceurs d’infiltration et caractérisée par des temps de séjour intermédiaires. Ces observations directes justifient la prise en compte du phénomène d’hystérèse dans la modélisation de la ZNS. Confirmant des modèles conceptuels existants, ce travail contribue au développement d’un modèle de fonctionnement de l’aquifère karstique, qui devra à terme être transposable aux autres systèmes méditerranéens. / The first study of karst aquifers unsaturated zone (UZ) functioning, by direct access, was conducted on the experimental area of the Fontaine de Vaucluse, including the underground gallery of the LSBB. This gallery intersects arbitrarily, within the UZ, the karst network and flow paths. Observed flows are distributed throughout the gallery corresponding to different limestone thicknesses (30 to 514m). 45 flow points were observed and followed at least once. The hydrodynamic and hydrochemical monitoring over 8 years show that: (i) the flows spatial and temporal organisation is a function of depth and the fracturing density, (ii) the hydrodynamic and hydrochemical flows signatures are based on rainfall amount also as the initial state of the system (iii) in order to precise the conceptual model of karst aquifers is necessary to consider the nonlinearity of the hydrodynamic system’s responses.Three flow components are deduced: (i) a slow component, permanent, which is active regardless of hydrological conditions, and is characterized by significant residence time, (ii) a fast component, active only during strong recharge periods as marked by infiltration tracers. This component is characterized by low residence time and (iii) an intermediate component, highlighted by hysteretic behavior, as marked also by the infiltration tracers and is characterized by intermediate residence times. Considering the hysteresis phenomenon in UZ modeling by these direct observations confirms earlier conceptual models. The ultimate goal is to contribute to the development of a karst aquifer model, which could be transposed to other Mediterranean karst systems.
77

Groundwater resource evaluation and protection in the Cape Flats, South Africa

Adelana, Segun Michael Adegboyega January 2010 (has links)
Philosophiae Doctor - PhD / The analysis of geologic, hydrologic and hydrogeologic data interpreted to give the characteristics of the Cape Flats aquifer showed the quality of groundwater from the aquifer is suitable for development as a water resource. The conceptual model of the Cape Flats sand shows an unconfined sandy aquifer, grading into semi-confined conditions in some places where thick lenses of clay and peat exists. Recharge rates through the saturated zone of the Cape Flats aquifer have been determined by water table fluctuation (WTF), rainfall-recharge relationship, soil water balance and chloride mass balance methods (CMB). Recharge rates using the WTF vary considerably between wet and dry years and between locations, with a range of 17.3% to 47.5%. Values obtained from empirical rainfall-recharge equation (method 2) agree with those of the WTF. Recharge estimates from the water balance model are comparatively lower but are within the range calculated using empirical method 2 (i.e. 87 - 194 mm or 4 – 21% of MAP). These recharge rates also agree with estimates from the series of other methods applied to sites located in the north-western coast of Western Cape and are comparable to recharge rates obtained elsewhere in the world. / South Africa
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Avaliação da qualidade da água subterrânea de poços ponteira no município de Osório, RS

Paim, Rosana Alves January 2018 (has links)
Este trabalho buscou avaliar a qualidade da água subterrânea de poços ponteira, que captam água do Sistema Aquífero Quaternário Costeiro (SAQC) na região de Osório (RS), através da aplicação de diferentes métodos. Para a realização do estudo foi feito um inventário e cadastramento de poços, o levantamento e interpretação de dados geológicos e hidrogeológicos, além da coleta e análise de amostras de água. Para este trabalho foram utilizados dados físico-químicos e bacteriológicos, obtidos através das análises de água (campo e laboratório), que foram coletadas em 26 poços. A avaliação dos resultados foi realizada através dos diagramas de Piper e Stiff, da comparação com os Valores Máximos Permitidos (VMP) em portarias de potabilidade e da aplicação de métodos de avaliação da qualidade da água e risco a saúde. Os resultados obtidos permitiram evidenciar que no município, a principal forma de captação da água subterrânea, ocorre por meio de poços ponteira que possuem profundidades na sua maioria, inferiores a 20 metros e que captam água de aquíferos granulares livres associados a camadas de sedimentos arenosos. Além disso, a maior parte das águas subterrâneas apresentaram valores de pH entre 5,6 e 6,5 e valores de condutividade elétrica (CE) entre 0 a 200 uS/cm. As concentrações de nitrato variaram entre 0 e 2 mg/L N-NO3, de cloretos e sódio não ultrapassam 30 mg/L, os sólidos totais dissolvidos entre 0 e 200 mg/L, indicando a ocorrência de águas doces com baixa mineralização. Os resultados das análises bacteriológicas indicaram a presença de Escherichia coli e coliformes totais. A comparação dos resultados das análises com os VMP da portaria do Ministério da Saúde Nº 2914/11 (Brasil, 2011), indicaram a ocorrência de poços que apresentam alterações nos parâmetros pH, amônia, ferro, cor, manganês, turbidez, bem como presença de Coliformes Totais e E.coli. Com o uso do Índice de Qualidade da Água Subterrânea (IQUAS), foram classificadas amostras de água como ótimas, boas e péssimas. Já o cálculo do Índice Relativo de Risco (IRR) evidenciou a ocorrência de amostras que apresentaram valores altos, a Avaliação de Risco à Saúde, indicou a ocorrência de amostras que apresentaram Risco não Carcinogênico. Por fim a partir deste estudo pode-se verificar que o uso de diferentes métodos para avaliação da qualidade da água, tem grande importância, pois torna mais consistente essa avaliação, já que cada método envolve a análise de diferentes parâmetros. / The aim objective of this work was to evaluate the groundwater quality of wells, which capture water from the Coastal Quaternary Aquifer System (SAQC) in the region of Osorio (RS), by applying different methods. In order to carry out the study, an inventory and registration of wells, the survey and interpretation of geological and hydrogeological data, as well as the collection and analysis of water samples. For this work, physicochemical and bacteriological data were obtained through water analysis (field and laboratory), which were collected in 26 wells. The evaluation of the results was carried out through the Piper and Stiff diagrams, the comparison with the Maximum Permitted Values (VMP) in potable water consumption and the application of water quality and health risk assessment methods. The results obtained showed that in the municipality, the main way of captation of groundwater occurs through pointer wells that have a depth of less than 20 meters and capture water from unconfined granular aquifers associated with layers of sandy sediments. In addition, most groundwater had pH values between 5.6 and 6.5 and values of electrical conductivity (EC) between 0 and 200 uS/cm. Nitrate concentrations ranged from 0 to 2 mg / L NNO3, with sodium chloride not exceeding 30 mg/L, total solids dissolved between 0 and 200 mg/L, indicating the occurrence of fresh water with low mineralization. The results of the bacteriological analyzes indicated the presence of Escherichia coli and total coliforms in 4 wells. The comparison of the results of the analyzes with the MPV of Ministry of Health No. 2914/11 (Brazil, 2011) indicated the occurrence of wells that present alterations in pH, ammonia, iron, color, manganese, turbidity and presence of Total Coliforms and E. coli. With the use of the Underwater Water Quality Index (IQUAS), 9 water samples were classified as optimal, 2 as good and 4 bad. The calculation of the Risk Index (IRR) evidenced the occurrence of 7 samples that presented high values, the Health Risk Assessment, indicating the occurrence of 2 samples that presented non-Carcinogenic Risk. Finally, from this study we can verify that the use of different methods to evaluate water quality, is of great importance, since it makes this evaluation more consistent, since each method involves the analysis of different parameters.
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Hydrologisk och hydrokemisk studie om Trehörningen : En igenväxande sjö i östra Uppland / Hydrological and Hydrochemical Study of Trehörningen : a Lake Threatened by Overgrowth in Eastern Uppland

Grunewald, Christoffer, Hofstedt, André, Winlund, John January 2020 (has links)
Lake overgrowth occurs in many areas in Sweden, and it is often explained by elevated amounts of nutrients. The overgrowth results in a changed local environment for both communities and ecosystems. In this project the lake Trehörningen, near Spersboda in Norrtälje municipality, has been examined regarding an ongoing overgrowth process. The study contains hydrological and chemical analyses and an inquiry to those living in the area. The purpose has been to survey the area and identify factors that may contribute to elevated nutrient levels, and to give suggestions to measures that may reduce the nutrient transport. The results from the period February–April 2020 indicate a moderate nutrient supply, but that certain areas are more exposed than others. The entire lake can not be seen as nutrient rich, and there is a net loss of nutrients from the lake over the period studied. The analysis of mass transports shows that the primary production in the lake is phosphorus limited, and that the largest addition of phosphorus comes from three streams that all supply the Spersboda bay. This bay is also the shallowest area of the lake and has the most visible emergent plant growth. Analyses of the lake sediments show a potential increase in phosphorus over time, and that there may be some internal loading, but it is unlikely to be a large source of phosphorus to the lake. The streams with the highest nutrient levels have their watershed mostly in human-impacted areas. The study has taken place before the plant growth season, and as such the absolute nutrient numbers may be elevated, but their relative amounts are worth discussing. To reduce the overgrowth process, measures which reduce the nutrient supply should be taken, especially in the watercourses around the Spersboda bay. / Igenväxning är ett problem som finns i många sjöar i Sverige och förklaras ofta med ökade halter av näringsämnen. Igenväxningen leder till en förändrad närmiljö för både samhällen och ekosystem. I detta projekt har sjön Trehörningen, intill Spersboda i Norrtälje kommun, undersökts med avseende på en pågående igenväxning. Undersökningen innefattar hydrologiska och kemiska mätningar, samt en enkät till de boende i området. Detta har gjorts för att kartlägga omgivningen, och se vilka faktorer som kan bidra till en ökad näringstillförsel, samt ge förslag på möjliga åtgärder. Resultaten från perioden februari–april 2020 visar överlag på en måttlig näringstillförsel, men att vissa områden har högre näringstillförsel. Sjön som helhet bör inte ses som näringsrik och totalt sett sker en nettoförlust av näringsämnen ur sjön under undersökningsperioden. Analys av masstransport för näringsämnen indikerar att primärproduktionen är fosforbegränsad och att de största tillskotten av fosfor kommer från tre vattendrag, som rinner till Spersbodaviken. Denna vik är även den grundaste, och mest beväxta. Analyser av sedimenten visar en möjlig ökning av fosforhalt över tid, och att viss internbelastning kan finnas, men är troligen inte en betydande fosforkälla. De vattendrag med höga halter av näringsämnen har främst sitt avrinningsområde på mark med mänskig påverkan. Undersökningen är gjord innan växtsäsongens början, vilket medför att de absoluta värdena troligen är förhöjda, men deras relativa påverkan kan diskuteras. För att motverka igenväxningen bör åtgärder som minskar tillförseln av näringsämnen göras, särskilt i Spersbodavikens tillrinnande vattendrag.
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Modélisation géologique 3D et hydrodynamique appliquées aux réservoirs carbonatés karstiques : caractérisation des ressources en eau souterraine de l'Unité du Beausset (Var et Bouches-du-Rhône, SE France)

Fournillon, Arnaud 28 September 2012 (has links)
Cette thèse a pour but de contribuer à l'étude des réservoirs carbonatés karstiques par une approche intégrant modélisation géologique numérique 3D et hydrogéologie. Une méthodologie originale a été ainsi développée pour être appliquée à la caractérisation des ressources en eau souterraine de l'Unité du Beausset (Bouches-du-Rhône et Var, SE France). Cette méthodologie lie l'architecture géologique 3D du réservoir à ses propriétés hydrodynamiques extraites de son étude hydrogéologique. Cette zone est un synclinal de roches sédimentaires mésozoïques d'une épaisseur pouvant atteindre 3000m. Ces roches affleurent sur environ 650 km², et ont subi de nombreuses phases de fracturation et karstification. A partir de la synthèse des données existantes géologiques, hydrogéologiques et karstologiques, sept intervalles lithostratigraphiques ont été définis. Ces intervalles ont également été caractérisés hydrodynamiquement par l'analyse des séries temporelles de hauteur, température et conductivité électrique enregistrées en continu en sept sources représentatives. Cette caractérisation a été complétée par des campagnes exhaustives d'hydrochimie et de mesures de débit. L'ensemble des données et des résultats obtenus ont permis de définir où sont les unités de stockages et d'écoulement de l'eau souterraine. Ces dernières ont été intégrées de manière qualitative en 3D à l'aide d'un modèle surfacique de l'architecture géologique de l'Unité du Beausset. Cette intégration a permis de définir les meilleures zones de captage potentiel pour de nouvelles ressources en eau souterraine. / The aim of this PhD thesis is to provide an original approach for the characterization of karstic carbonate reservoirs that integrates 3D geological modeling and hydrodynamics. The 3D geological model stands for the structural compartmentalization of the reservoir and the hydrodynamics provide dynamic properties for the understanding of the fluid flow. This methodology is applied to the characterization of the groundwater resources of the Beausset Unit (SE France). The study area is a syncline composed of nearly 3000 m of Mesozoic sedimentary rocks, which age from late Triassic to Upper Cretaceous. These rocks, which are mainly carbonates, crop out over an area of 650 km² and have known several phases of fracturation and karstification. This study is divided in four parts: (1) synthesis of existing data, (2) 3D geological modeling, (3) study of hydrodynamics, and (4) integration of static and dynamic data in order to discuss the characterization of the groundwater resources in the Beausset Unit. The existing data on stratigraphy, lithology, petrophysical properties, karstology and hydrogeology allow the definition of seven lithostratigraphic intervals that have been chosen for modeling. These intervals represent the vertical compartmentalization of the reservoir: each interval has a unique combination of karst and rocks properties. The integration of all this data end results leads to the recognition of the flow and reservoir units in each lithostratigraphic interval. A qualitative link has been made between the 3D architecture of the basin and the reservoir properties; it allows the characterization of the best potential targets for new groundwater tapping zones.

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