Submitted by Roger Dias Gonçalves (rdgon@hotmail.com) on 2016-10-11T14:42:15Z No. of bitstreams: 1 Goncalves_Roger_2016_MestradoGeociencias_Modelagem Numérica e Avaliação Hidrogeológica do Aquífero Rio Claro.pdf: 14855876 bytes, checksum: 2f50cc1293a8252d613593e19e5e8dc9 (MD5) / Approved for entry into archive by Juliano Benedito Ferreira (julianoferreira@reitoria.unesp.br) on 2016-10-17T19:40:03Z (GMT) No. of bitstreams: 1 goncalves_rg_me_rcla.pdf: 14855876 bytes, checksum: 2f50cc1293a8252d613593e19e5e8dc9 (MD5) / Made available in DSpace on 2016-10-17T19:40:03Z (GMT). No. of bitstreams: 1 goncalves_rg_me_rcla.pdf: 14855876 bytes, checksum: 2f50cc1293a8252d613593e19e5e8dc9 (MD5) Previous issue date: 2016-10-04 / 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.

L’Afrique de l'Ouest est sujette à une variabilité climatique importante et elle connaît une longue période de sécheresse depuis les années 1970 dont l’impact sur les ressources en eau souterraine reste peu étudié. La présente étude porte sur le bassin versant du Kou au Burkina Faso qui abrite une grande réserve d’eau souterraine à l’origine de sources exceptionnelles. Cette ressource, essentielle pour les besoins de la population, présente pourtant des signes d'épuisement qui soulèvent une question essentielle : quelle est la part du climat et celle des prélèvements dans l’épuisement de cette ressource ? Pour répondre à cette question, nous avons utilisé des méthodes d’analyse statistique et la modélisation hydrogéologique. Les méthodes statistiques ont été appliquées aux chroniques de données climatiques, hydrométriques et piézométriques. Elles ont permis de décrire la réponse des eaux souterraines aux forçages du climat et d’identifier les facteurs explicatifs du comportement de la nappe. La modélisation hydrogéologique a pallié certaines limites de ces méthodes statistiques par une meilleure prise en compte de l’hétérogénéité spatiale de l’aquifère. Elle a en particulier montré que les pompages ont un impact significatif sur la ressource en eau. En somme, les déficits de précipitation, combinés aux pompages en croissance continue, mettent en péril la ressource. La gestion de cette dernière dans une perspective durable devrait donc revêtir une attention particulière. / West Africa is prone to critical climate variability and since the 1970s has been experiencing a long period of drought whose impact on groundwater resources is little studied. This study focuses on the Kou catchment in Burkina Faso which holds a large groundwater resource that lies at the root of exceptional springs. This resource, essential to fulfill the populations’ needs, shows signs of depletion that raises a critical question: what is the share of climate and that of withdrawals in the depletion of the resource? To answer this question, we used statistical analysis methods and hydrogeological modeling. The statistical methods were applied to climatic, hydrometric and groundwater level time series to describe the groundwater’s response to climate forcing and to identify explanatory factors of the groundwater’s behaviour. The hydrogeological modeling overcame some of the statistical methods limitations by better heeding the spatial heterogeneity of the aquifer’s characteristics. Particularly, it revealed that pumping have significant impact on the resource. To sum up, rainfall deficits combined with growing pumping endanger the resource. Hence, sustainable management of the resource should be a critical issue to pay attention to.

Philosophiae Doctor - PhD / The study addressed the groundwater assessment and sustainable management of the coastal alluvial aquifers in Namib Desert, the Omaruru River Delta Aquifer (Omdel Aquifer) was used as a case study. Sustainable utilization of groundwater in parts of hyper-arid Sub-Saharan Africa, like the Namib Desert, is always a challenge due to lack of resources and data. Understanding of hydrogeological characteristics of the Omaruru Delta Aquifer System is a pre-requisite for the management of groundwater supply in the Central Namib area (Namib Desert). For the Omdel Aquifer in the Omaruru catchment, Namibia, issues to investigate include the lack of information on the geology and hydrogeological setting, the hydraulic properties and geometry of the aquifer at the inflow and outflow sections, groundwater recharge conditions upstream of the aquifer, and the impact of artificial recharge.

Philosophiae Doctor - PhD / The study addressed the groundwater assessment and sustainable management of the coastal alluvial aquifers in Namib Desert, the Omaruru River Delta Aquifer (Omdel Aquifer) was used as a case study. Sustainable utilization of groundwater in parts of hyper-arid Sub-Saharan Africa, like the Namib Desert, is always a challenge due to lack of resources and data. Understanding of hydrogeological characteristics of the Omaruru Delta Aquifer System is a pre-requisite for the management of groundwater supply in the Central Namib area (Namib Desert). For the Omdel Aquifer in the Omaruru catchment, Namibia, issues to investigate include the lack of information on the geology and hydrogeological setting, the hydraulic properties and geometry of the aquifer at the inflow and outflow sections, groundwater recharge conditions upstream of the aquifer, and the impact of artificial recharge. Omdel Aquifer occurs in a desert environment with less than 20 mm of rainfall per annum, it’s regarded to receive no direct groundwater recharge from rainfall, only from occasional (inconsistent) flooding of the Omaruru River, due to periodic thunderstorms in the upstream catchment. Since the Omdel Aquifer does not receive direct recharge from rainfall, an artificial recharge scheme was implemented to augment the water supply. One of the objectives of the study is to integrate artificial recharge with hydrogeological understanding of the Omdel Aquifer to establish a conceptual framework for assessment of groundwater recharge and discharge, water chemistry and balanced water supply.

京都大学 / 新制・課程博士 / 博士(工学) / 甲第23172号 / 工博第4816号 / 新制||工||1753(附属図書館) / 京都大学大学院工学研究科都市社会工学専攻 / (主査)教授 角 哲也, 准教授 竹門 康弘, 准教授 Sameh Kantoush / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DGAM

Située à l'interface entre les eaux de surface et les eaux souterraines, la zone hyporhéique (ZH) est depuis maintenant plusieurs décennies considérée comme une zone cruciale pour la préservation des milieux aquatiques. Elle constitue souvent un indicateur fiable de la bonne qualité des eaux et une niche écologique primordiale pour de nombreuses espèces. Mais elle est aussi le lieu d'interaction entre deux masses d'eau de signature différente, ce qui conduit à la formation d'un milieu extrêmement fragile et siège d'un grand nombre de réactions biogéochimiques. L'objectif principal de cette thèse est de parvenir à une meilleure compréhension de la dynamique des échanges au sein de la zone hyporhéique. L'approche de cette problématique s'est faite sous un aspect innovant en couplant une démarche hydrogéologique "classique" à l'aide de mesures hydrodynamiques et géochimiques, et l'utilisation de la tomographie de résistivité électrique (ERT). Plusieurs campagnes de terrain ont été menées sur la rivière Essonne, choisie comme lieu d'expérimentation. Différents outils de prélèvement et/ou de mesure ont été mis en place et un grand nombre de mesures à différentes périodes de l'année ont été réalisées. Des expériences assez techniques et innovantes de suivi d'un abaissement et relèvement de barrage, ainsi qu'un traçage artificiel au sel ont pu être effectués grâce à la collaboration avec le syndicat chargé de la gestion et l'aménagement d'une partie du réseau hydrographique de l'Essonne (SIARCE). En parallèle avec cette étude expérimentale, une maquette numérique 3D de la zone d'étude a été réalisée à l'aide du logiciel HydroGeoSphere. Des tests de sensibilité ont permis d'identifier les paramètres hydrodynamiques les plus importants et de quantifier leur impact sur la formation et l'évolution de la zone hyporhéique. Finalement, les premières simulations des expériences menées sur le terrain ont permis de confronter l'approche expérimentale et l'approche théorique. / The Hyporheic Zone (HZ) is located at the interface between surface water and groundwater. For several decades it is considered as a hotspot for the development of a rich aquatic environment in rivers. Its system is often considered as a reliable indicator for water quality and a primary ecological niche for many species. From a hydrological point of view, it is also the place of interaction between two distinct water bodies with different geochemical signatures. This place of mixing forms a very fragile equilibrium where many biogeochemical reactions can occur. The objective of this thesis is to reach a better understanding of mixing and water fluxes in a dynamic context within the hyporheic zone. An innovative method was used by coupling a "classic" hydrogeological approach with hydrodynamic and geochemical measurements with Electrical Resistivity Tomography (ERT). Several field campaigns were done on the Essonne river as experimental site. A large number of measurements were done at various periods of the year and field equipment for water sampling and measurements were installed during these three years. Technical and innovative experiments were conducted such as a dam lowering and rising and an artificial salt tracer test in collaboration with the federation in charge of organization and management of the Essonne network. Finally, a 3D-model of the studied area was built with the HydroGeosphere software. The main hydrodynamic parameters have been tested in order to understand their impact and their variation in a static or dynamic environment on the hyporheic system and its development. In addition, field experiments were reproduced to compare the experimental and theoretical approach.

Growing regions and tighter zoning in urban areas are pushing the hydrological bal-ances to establish new equilibriums which are causing a stress on the groundwater. Urbanization can affect the groundwater in several ways in which both raising and lowering of groundwater tables are a possibility. Both ways, sudden changes may bring on socioeconomic costs for the unprepared. Hydrogeological modelling creates the possibilities to visualise processes that cannot be seen with the naked eye. By combin-ing knowledge about the studied area from tests and measurements a conceptual model and additionally a numerical model can be created. To study the magnitude groundwater sensitivity to changes in land-cover a hydrogeological model was created using COMSOL multiphysics within the frame of a case study concerning a horse racetrack located in Täby, north of Stockholm. The model was calibrated against known data and was the applied on a future scenario where both the land-use and climate were changed. The outcome of the model showed that hydrogeological mod-elling is sensitive to the amount and quality of the in-data. Several insecurities in the results can be traced back to a lack of base material and by changing one parameter the result of other calibrated parameters would also change. Equifinality could thus be established to be a major issue when performing groundwater modelling. Further studies of relevant data requirements for different model objectives are required.

>Magister Scientiae - MSc / Hydrogeological characterization of an aquifer system is a first step to determine groundwater quantity, yield potential, socio-economic value, storage capacity and aquifer transmissivity properties of an aquifer as a water resource. Derivative analysis is a technique that has been used to understand groundwater flow systems. This is mainly because derivative analysis of pumping test data and curve matching improves the understanding of aquifer types and hydrogeologic setting of a study site. Time vs drawdown curves produced through pumping tests serve as the most useful tools to analyse aquifer characteristics. The study was conducted through performing pumping test in boreholes of hospital facilities in the Western Cape drilled on the TMG and Malmesbury formation. / 2023

<p>The focus of this thesis is on groundwater vulnerability assessment by process-based simulation models and data acquisition for these assessments. A modelling system for intrinsic groundwater vulnerability assessment in water supply areas was developed, consisting of flow- and transport models for the unsaturated zone and the groundwater zone, coupled to a geographical informa-tion system. The system was applied to a water supply area located close to a major road south of Stockholm. Chloride was used as an indicator in determining the vulnerability for groundwater contamination from the road. The approach was useful to illustrate the dynamic change of chlo-ride concentrations both during the stage of continuous application and after the applications was terminated. A structure and content of a database for flow and transport modelling, based on hydrogeological environments, was outlined. An existing hydrogeological parameter database, HPAR at the Geological Survey of Sweden (SGU), was examined as a potential source of data for the new database. Values for some important parameters needed for groundwater modelling, such as hydraulic conductivity and effective porosity, were lacking in the three municipal HPAR databases that were studied. It was suggested that these data should be added, together with information on the hydrogeological environments, for all geographical positions of interest. Without such minimum information, the efficient use of modelling tools could not be expected.</p><p>Typical profiles of three common Swedish hydrogeological environments (sand deposits, glacial till and clay covered areas) were used to represent generic input data to model simulations in the unsaturated zone so that the importance of soil, vegetation type and groundwater levels on turn-over times of conservative contaminants transported by natural recharge could be examined. The same profiles were used to predict the penetration depth of accidental liquid spills that occur at the land surface level. In the case of contaminant transport by natural recharge, water storage in the soil profile and vegetation type played an important role for turnover times. For liquid spills, the hydraulic con-ductivity was found to be of major importance, while the water retention properties were of less importance. Modelling, together with available data sources, were successfully used to demon-strate the vulnerability of different environmental conditions.</p>

Realizar a modelagem de um aqüífero não é tarefa fácil. Em se tratando de um sistema aqüífero, a empreitada se torna ainda mais complexa. Neste trabalho, alguns dos parâmetros importantes para esse fim foram estimados a partir de simulações. Na região de estudo, existem poços tubulares que, em sua maioria, não foram perfurados somente na Formação Adamantina, mas também na Formação Serra Geral. Tal configuração conduziu à formulação de dois conjuntos de cenários a partir dos quais foi possível estimar valores de condutividade hidráulica para as duas formações. Com essa estimativa conseguiu-se também simular testes de bombeamento, seus respectivos cones de rebaixamento, bem como a interferência causada entre cones de rebaixamento. Com essa abordagem foi possível estimar o quanto um poço em funcionamento pode influenciar no nível estático de um vizinho. A contribuição da geofísica está no uso da eletroresistividade. Foram executadas 23 Sondagens Elétricas Verticais (SEV), das quais dezenove são SEV´s curtas (AB/2 500m) e quatro, longas (AB/2 1500), que forneceram informações sobre a espessura saturada do arenito e posição do topo do basalto, especialmente na região com poucos poços. Também foram realizados quatro Caminhamentos Elétricos (CE) no estudo de possíveis estruturas. Unindo os resultados da modelagem (simulação) e da geofísica, pôde-se relacionar os parâmetros hidrogeológicos e geoelétricos. Embora o conjunto de dados para a região não tenha sido o ideal, a metodologia se mostrou adequada e os resultados bastante razoáveis. Deste modo, foi possível a determinação de parâmetros hidrogeológicos em subsuperfície através de parâmetros geoelétricos medidos em superfície. / To perform the aquifer modelling is not an easy task. In the case of an aquifer system, the work becomes even more complex. In this work, some of important parameters for this purpose have been estimated from simulations. In the study area, there are wells that in most cases were not only drilled in Adamantina Formation but also in Serra Geral Formation. This configuration led to the formulation of two sets of scenarios from which it was possible to estimate values for hydraulic conductivity of these formations. With this estimate it could also simulate pumping tests, their cones of depression as well as the interference caused between cones of depression. With this approach it was possible to estimate how much a operating well can influence static level of a neighbour one. Geophysics contribution is in the use of electrical resistivity. Twenty-three Vertical Electrical Soundings (VES) were performed, nineteen of them are short (AB/2 500m), that provided information about the saturated thickness of sandstone as well as top of basalt, especially in the region with few wells, and four are long (AB/2 1500) VESs. Four electrical profiling (EP) were also carried out to study possible structures. Joining modelling (simulation) and geophysics results, it could be related hydrogeological and geoelectrical parameters. Although dataset for region was not the ideal, methodology was satisfactory, and results quite reasonable. Thus, it was possible to determine hydrogeological parameters in subsurface through measured geoelectrical parameters in surface.