Analytical solutions to well hydraulic problems have restrictive assumptions that often do not match real world conditions. Although numerical models more closely match reality, they either ran too slowly to be practical or lacked accuracy because of coarse grid spacing and large time steps. Advances in computer power over the last few decades now allow for accurate, fast numerical models that handle complex flow systems. The purpose of this dissertation was to develop flexible and accurate numerical modeling codes for the simulation of hydrologic tests. One of these numerical modeling codes, the Slug Test Simulator (STS), was designed for the mechanics of a single well test, or slug test. STS can handle a variety of conditions including unconfined flow, partial penetration, layered heterogeneities, and the presence of a homogeneous well skin like existing codes. This program also extends on the capabilities of earlier codes with its ability to simulate a heterogeneous skin where K can vary in both the radial and vertical directions. STS has a clear user interface, can display graphical results, and allows the user to determine hydraulic conductivity through a trial-and-error curve-matching process. Comparisons of STS to the Cooper-Bredehoeft-Papadopulos analytical solution and the Kansas Geological Survey (KGS) semi-analytical solution produced near-identical curves under a wide variety of conditions. Numerous analytical studies have shown that the well skin is an important factor in the underestimation of hydraulic conductivity in slug tests. STS allows for the exploration of the well skin issue under conditions too complex for analytical models. Model trials revealed two key discoveries: 1) if any layers within the skin have the same hydraulic conductivity as the surrounding formation, flow is concentrated within these conduits and the resultant head response approaches the case when no skin is present; and 2) the two most important properties in determining the overall influence of the skin are specific storage and skin thickness. The first discovery suggests that extensive development activities can essentially eliminate any well skin impacts. Other factors such as partial penetration, the placement of the well screen, and anisotropy play insignificant roles in resultant head responses. Recent research is focusing on alternative direct- push (DP) methodologies to determine hydrologic properties. DP offers advantages over traditional well tests, but may yield inaccurate results if the screen becomes clogged during pushing activities. The Kansas Geological Survey (KGS) developed a new DP technique, the Direct-Push Permeameter (DPP), to overcome this limitation. Existing analytical or numerical models cannot address the specialized nature of DPP tests so a second numerical modeling code, the Direct Push Permeameter Simulator (DPSS), was developed. DPPS was generated by modifying STS so both numerical codes are similar in many ways, particularly with their flexibility and accuracy. The codes differ in how they handle vertical layering, the boundary conditions at the well, and the spreadsheet interfaces. DPPS was able to produce near-identical curves in comparison to the Theis analytical solution. DPPS was also able to reasonably recreate DPP field data conducted at two sites with distinctly different media properties. The GEMS and Nauen sites had an average error of 14.2% and 3.1%, respectively between the field data and DPPS simulations.

Made available in DSpace on 2014-06-11T19:32:18Z (GMT). No. of bitstreams: 0 Previous issue date: 2003-05-07Bitstream added on 2014-06-13T19:21:50Z : No. of bitstreams: 1 monteiro_rc_dr_rcla_prot.pdf: 4665418 bytes, checksum: dde6d49aac814ef6534e6a4772d1b77e (MD5) / A cidade de Ribeirão Preto (SP) é um pólo regional de desenvolvimento, com sua história baseada na imigração e agronegócio, destacando-se no cenário paulista como pólo universitário, hospitalar, industrial e político. Com uma população que ultrapassa 500 mil habitantes, sua demanda hídrica é 100% suprida pela captação de águas do aqüífero. O principal aqüífero sob Ribeirão Preto é o Sistema aqüífero Guarani. Os arenitos das formações Pirambóia e Botucatu, que perfazem o arcabouço geológico do aqüífero, são aflorantes na porção nordeste do município, uma área de baixa densidade populacional, porém indicada pela administração pública como área de expansão urbana. O município de Ribeirão Preto representa um exemplo clássico de área urbana em desenvolvimento e seu efeito na exploração intensiva do aqüífero. Este trabalho apresenta algumas características do município, uma discussão sobre sobrexplotação e problemas na gestão dos recursos hídricos subterrâneos no meio urbano e a máxima Entropia Bayesiana como proposta metodológica para o mapeamento espaço-temporal de fenômenos naturais. No caso estudado, entretanto, os dados disponíveis (de baixa qualidade)e dificuldades com a metodologia não permitiram a formulação de um modelo preditivo satisfatório para o diagnóstico da situação e apropriada de gestão ambiental e dos recursos hídricos subterrâneos do município. / The city of ribeirão Preto (SP) is a regional center of development, with a history based on immigration and agribusiness, standing out in the state as an academic, medical, industrial and political hub. With a population that surprasses 500,000 inhabitants, its water demands are supplied solely by grounwater extraction. The main aquifer under Ribeirão Preto is the Guarany aquifer System. The sandstones of Pirambóia and botucatu formations, which make up the aquifer's geological framework, crop out in the northeast portion of the municipal district. While this northeast area is of low population density, it is slated for future urban expansion area by the public administration. The municipal district of Ribeirão Preto represents a classic example urban growth and its effects on aquifer intensive exploration. This work presents some characteristics of the city, a discussion on overexploitation and problems on groundwater resource management in the urban areas, and Bayesian Maximum Entropy as methodological proposition for the space-time mapping phenomena. In this case study, however, the available data (low quality) and dificults related to the methodology did not permit the formulation on a suitable predictive model for the situation diagnose and appropriate municipal groundwater resource management plans and environmental management.

Made available in DSpace on 2014-06-11T19:32:22Z (GMT). No. of bitstreams: 0 Previous issue date: 2003-11-05Bitstream added on 2014-06-13T19:42:57Z : No. of bitstreams: 1 silva_fp_dr_rcla.pdf: 7470274 bytes, checksum: b2bb81f9bbd84686218ba54076b5d9fc (MD5) / Estudos utilizando perfis geofísicos e dados de poços permitiram estabelecer o arcabouço estratigráfico e hidroestratigráfico, de superfície, das rochas mesozóicas do Grupo Bauru, da Bacia do Paraná, em São Paulo. Duas superfícies de discordância regionais, S1 e S2, de caráter cronoestratigráfico, foram identificadas, constituindo-se em excelentes horizontes-guia para distinção e delimitação de unidades geofísicas, correspondentes às unidades litoestratigráficas formais. A primeira delimita os estratos atribuídos às formações Caiuá/Pirapozinho, abaixo, e Santo Anastácio, acima; a segunda marca o contato entre e formação Santo Anastácio, abaixo, e os sedimentos das formações Araçatuba e Adamantina, acima. Os critérios de correlação utilizados permitiram estabelecer novas relações litoestratigráficas para o Grupo Bauru. Foram identificadas as formações Caiuá, Santo Anastácio, Araçatuba, Adamantina e Marília, e reconhecidas duas novas unidades litoestratigráficas, denominadas de Formação Pirapozinho e Formação Birigüi. O substrato basáltico apresenta-se compartimentado em depressões e altos internos, orientados preferencialmente NE-SW. As principais estruturas identificadas foram as depressões de Presidente Bernardes, Dracena, Sud Menucci, Queiroz e Rio Preto, e os Altos de Tanabi, Pereira Barreto e Paraguaçu Paulista. A evolução da sedimentação do Grupo Bauru foi marcada pelo controle tectônico do substrato na localização e migração dos depocentros, e pela atuação expressiva da erosão. / Subsurface studies using geophysical logs and well data obtained from water wells were fundamental in defining stratigraphic and hydrostratigraphic frameworks of the Mesozoic Bauru Group sedimentary units of Paraná Basin, in the State of São Paulo. In the present study two important regional unconformity surfaces were identified - S1 and S2 - constituting excellent markers which can be correlated to formal litostratigraphic units. SI separates underlying Caiuá and Pirapozinho formations from overlying Santo Anastácio Formation. S2 surface is coincident with the contact between underlying Santo Anastácio Formation and overlying Araçatuba and Adamantina formations. New lithostratigraphic relationsbips for the Bauru Group were obtained applying correlation and interpretation criteria based upon regional unconformity surfaces. Caiuá, Santo Anastácio, Araçatuba, Adamantina and Marília formations were recognized in subsurface in addition to two new formations named Pirapozinho and Birigui. The basaltic substrate is segmented showing a prominent high, oriented NE-SW, separating two major basinal lows. The major structural features identified are Presidente Bernardes, Dracena, Sud Menucci, Queiroz and Rio Preto depressions and Tanabi, Pereira Barreto and Paraguaçu Paulista highs. The sedimentary evolution of Bauru Group is marked by the structural control of basaltic substrate of depocenters and by very active erosion.

No passado, a disposição de resíduos sólidos sem nenhum tipo de tratamento e controle era algo normal e muito praticado. Em conseqüência, as áreas de disposição transformaram-se em um sério problema de caráter ambiental e de saúde pública. Uma solução encontrada foi reutilizar essas áreas como depósitos de resíduos sólidos, mas agora de forma segura em construções conhecidas como aterros sanitários. O objetivo do presente trabalho é analisar a água subterrânea sob uma célula de disposição de resíduo de origem municipal construída em um antigo terreno utilizado como depósito indiscriminado. Para isso, foram pesquisadas as características físicas da área (geomorfologia, geologia, hidrometeorologia e hidrogeologia). A partir da hidrometeorologia, foi estimada a quantidade de água meteórica sob a célula central e esta foi comparada com a produção de lixiviado produzido na célula central, a diferença entre o estimado (34.006m3) e o produzido (36.338m3) foi de 6,42% para o ano de 2005. Para obter a caracterização da qualidade da água subterrânea foram realizadas amostragens da água subterrânea e água superficial em torno da célula central ao longo dos anos de 2005 e 2006, com intervalos de três meses entre uma campanha e outra. Os parâmetros que apresentaram resultados acima dos valores orientadores para águas subterrâneas (CETESB, 2005 e Portaria 518, 2004) foram: alumínio total, arsênio total, bário total, chumbo total, cloreto total, coliformes totais, cor, ferro total, manganês total, mercúrio total, níquel total, sólidos dissolvidos totais, sulfato e turbidez. Já os parâmetros que apresentaram resultados acima dos valores de intervenção para águas superficiais classe III (CONAMA, 2005) foram: alumínio total, cor, fosfato total, fósforo total, manganês total, odor, óleos e graxas e sólidos totais. Os resultados dessas análises indicam que existe uma alteração das águas, provavelmente devido aos antigos resíduos que ainda são uma fonte de contaminação, mas não apresentaram evidências de que a célula central de disposição de resíduos esteja participando da alteração da água subterrânea e superficial. / In the past, the disposal of solid residue without any type of treatment and control was a common and widespread practice. As a result of that, the old areas used as dump have become a serious environmental and public health problem. Some of these areas are being reused in constructions now known as landfills, this time in a way that they arent a threat anymore. The objective of this research is to analyze the groundwater under a municipal area of residue disposal built on the land of an old irregular dump. For this purpose, the physical characteristics of the area (geomorphology, geology, hydrometeorology and hydrogeology) were studied. With the results from the hydrometeorology analyzes it was possible to estimate the quantity of meteoric water under the central cell which was compared to the production of leachate in the central cell; the difference between the estimated (34.006m3 ) and the produced (36.338m3) was 6,42% in 2005. To characterize the groundwater quality, samples from ground and superficial water were taken from the area surrounding the central cell every three months during 2005 and 2006. The parameters whose results are above reference values for groundwater (CETESB, 2005 e Portaria 518, 2004) were: aluminum, arsenic, barium, lead, chlorate, coliform total, color, iron, manganese, mercury, nickel, solids total dissolved, sulphate and turbidity. The parameters whose results were above intervention value for superficial water class III (CONAMA, 2005) were: aluminum, color phosphate, phosphor, manganese, odor, oils and grease and solids dissolved. The results of these analyzes indicate that theres an alteration in these waters, probably due to old residues disposed of that are still a source of contamination, but these results didnt provide any evidence as of to prove that the central cell is participating in this alteration of the ground and superficial water.

Magister Scientiae - MSc / The focus of this work was to monitor and evaluate the hydrochemical characteristics of the groundwater in the Incomati Estuary for a period of one year. The aims of this work were to evaluate the groundwater chemistry data for any spatial and temporal variations and to evaluate the suitability of the groundwater for drinking and irrigation purposes. / South Africa

Orientador: Paulo Cesar Lodi / Banca: Ilza Machado Kaiser / Banca: Ana Flávia Vieira Pontes de Moraes / Resumo: Este trabalho identificou, mapeou e avaliou diversos parâmetros relacionados a poços tubulares profundos da região noroeste do estado de São Paulo. Foram analisados: aquíferos explorados, profundidades, evolução das perfurações, vazões médias, vazões específicas, transmissividades, níveis dinâmicos e estáticos, espessura dos aquíferos, horas de funcionamento, custos e eficiência energética. Foram analisados dados de 331 poços localizados em 83 municípios divididos nas regiões de: Lins, Fernandópolis, Jales, Novo Horizonte e Monte Alto. As ferramentas aplicadas para análises foram as estatísticas, através de tabelas e gráficos do Microsoft Excel e mapas temáticos georreferenciados através do ArcGis. Alguns dos resultados obtidos foram: a idade média dos poços é de 32 anos; o maior número de perfurações ocorreu entre as décadas de 70 e 80; as medianas das vazões específicas por aquíferos resultaram em: Bauru (1,13 m3/h.m), Serra Geral (1,74 m3/h.m), Guarani (5,65 m3/h.m) e Passa Dois (6,16 m3/h.m); as medianas das transmissividades por aquíferos resultaram em: Bauru (29,69 m2/s), Serra Geral (29,77 m2/s), Guarani (162,24 m2/s) e Passa Dois (189,87 m2/s). Os desvios padrões da maioria dos parâmetros resultaram bastante altos. Os resultados mostraram que é grande a dificuldade de se fazer uma previsão acertada dos valores dos parâmetros que o poço apresentará. Isto se deve à grande variabilidade de origens e evoluções das formações. Porém, com a disponibilização de informações de... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: This work identified, mapped and evaluated several parameters related to deep tubular wells in the northwest region of the state of. The following were analyzed: explored aquifers, depths, perforation evolution, average flow rates, specific flow rates, transmissivity, dynamic and static levels, aquifer thickness, operating hours, costs and energy efficiency. Data from 331 wells located in 83 municipalities divided in the regions of: Lins, Fernandópolis, Jales, Novo Horizonte and Monte Alto were analyzed. The tools applied for analysis were the statistics, through tables and graphs of Microsoft Excel and thematic maps georeferenced through ArcGis. Some of the results obtained were: the average age of the wells is 32 years old; the largest number of perforations occurred between the 70's and 80's; median specific flow rates by aquifers resulted in: Bauru (1,13 m3/hm), Serra Geral (1,74 m3/hm), Guarani (5,65 m3/hm) and Passa Dois (6,16 m3/h.m); the median of the aquifer transmissivity resulted in: Bauru (29,69 m2/s), Serra Geral (29,77 m2/s), Guarani (162,24 m2/s) and Passa Dois (189,87 m2/s). The standard deviations of most parameters turned out to be quite high. The results showed that it is very difficult to make a correct prediction of the parameter values that the well will present. This is due to the great variability of origins and evolution of the formations. However, by providing information from wells already drilled, it is possible to organize a database and georefere... (Complete abstract click electronic access below) / Mestre

<p>This thesis describes the geomorphology and hydrogeology of karst systems in portions of the northeastern Canyon Ranges of the Mackenzie Mountains and the Norman Range of the Franklin Mountains, N.W.T. In the region, mean annual temperatures are -6 to -8°C, total annual precipitation is 325 to 500 mm, and permafrost has a widespread to continuous distribution. The area was glaciated in the Late Wisconsinan by the Laurentide Ice Sheet.</p> <p>The Canyon Ranges and Norman Range are composed of a sequence of faulted and folded miogeoclinal sedimentary rocks that span the Proterozoic to Eocene. The geology is reviewed with an emphasis on strata that display karst. Included are several dolomite and limestone formations, two of which are interbedded with evaporites in the subsurface. The principal groundwater aquifer is the Lower Devonian Bear Rock Formation. In subcrop, the Bear Rock Formation is dolomite and anhydrite, outcrops are massive calcareous solution breccias. This is the primary karst rock.</p> <p>The regional distribution and range of karst landforms and drainage systems are described. Detailed mapping is presented from four field sites. These data were collected from aerial photography and ground surveys. The karst has examples of pavement, single and compound dolines, subsidence troughs, polje,sinking streams and lakes, and spring deposits. The main types of depressions are subsidence and collapse dolines. Doline density is highest on the Bear Rock Formation. Surficial karst is absent or less frequent in the zone of continuous permafrost or outside the glacial limit.</p> <p>At the field sites, water samples were collected at recharge and discharge locations. Samples were analyzed for a full range of ionic constituents and many for natural isotopes. In addition, several springs were monitored continuously for discharge, temperature, and conductivity. Dye tracing established linkages between recharge and discharge at some sites. These data are summarized for each site, as is the role of permafrost in site hydrology.</p> <p>The relationships between geological structure, topography, and groundwater systems are described. Conduit aquifers are present in both dolomite and limestone. These systems are characterized by discharge waters of low hardness and dissolved ion content. Aquifers in the Bear Rock Formation have a mixed flow regime and often have highly mineralized discharge. At the principal field site, there was a time lag of 40 to 60 days between infiltration and discharge in this unit. At a second site, flow through times were on the order of years. Variability in these systems is attributed to bedrock properties and boundary conditions.</p> <p>Preliminary rates of denudation are calculated from the available hydrochemical data. Total solutional denudation at the primary field site is approximately 45 m³ km^-2 a^-1 (mm ka^-l). The majority is attributed to the subsurface dissolution of halite and anhydrite. The predominance of subsurface dissolution is linked to the high frequency of collapse and subsidence dolines and depressions.</p> <p>The karst features and drainage systems of the northern Mackenzie Mountains date to the Tertiary. Glaciation has had a stimulative effect on karst development through the subglacial degradation of permafrost and the altering of boundary conditions by canyon incision.</p> / Doctor of Philosophy (PhD)

Master of Science / Department of Geology / Saugata Datta / The incidence of high arsenic (As) and other oxyanions (e.g. Mn) has been examined in a ~410km[superscript]2 areas within the Bengal Delta between North and South Matlab, Bangladesh. The aim of this study was to examine the role of sediment geochemistry, coupled with microbial community studies and their relations with different colors and grain sizes of sediments, in determining evolved groundwater hydrochemistry within the aquifers in Matlab. Groundwaters are Ca–Mg–HCO[subscript]3- types in shallow aquifers, Mg-HCO[subscript]3- in the intermediate depths and Na-K-Cl rich in the deeper aquifers. Dissolved As concentration is high (~781μg/l) associated with shallow grey and dark grey sediments, whereas light grey sediments at intermediate depths contain lower As (<10 μg/l). Dissolved Fe[superscript]T on other hand in both sediment types (light grey and grey) shows good correlation with dissolved SO[subscript]4[superscript]2-. In plots of [delta]δ[superscript]18O vs [delta]δD, intermediate and deeper depth aquifer waters plot on the arrays for LMWL and GMWL, which indicates the principal recharge mechanism is likely to be from local precipitation within the shallow aquifers. Only the high As groundwaters deflect from the LMWL, indicating that recharge might be a mixture of precipitation and surficial discharges / infiltrations for these waters. Bulk extraction of sediments showed that grey and dark grey sediments from shallow depths have higher As concentrations (~31 mg/kg) and light grey sediments have comparatively less (~11mg/kg). Sequential extractions for sediment fractionations showed that most of the As was bound to amorphous and poorly crystalline hydrous oxides of Fe and Al phases. Synchrotron-aided bulk-XANES studies conducted on sediments revealed As and S speciation in the core samples at different depths indicating the occurrences of hotspots of As distributed randomly in light grey and grey sediments. As[superscript]3+ is the dominant species in Matlab sediments. More than 101 bacterial families were identified among the eight sediment samples from the South Matlab core and out of them fewer than six families comprised more than ~80% of total bacterial families. Our results indicate significant relationships between bacterial community structure, grain size fractionation, dissolved As concentration and sediment C, Mn, and Fe concentrations for these samples. Groundwater abstracted from these light grey sediments, in contrast to reduced greyish to dark greyish sediments, contain significantly lower amounts of dissolved As and can be a source of safe water for the future. Our work demonstrates that intermediate depth light grey sediments have geochemical and microbial features conducive with safe drinking water for the future.

The intermontane Mackenzie Basin is located within the central South Island of New Zealand. The glacial basin contains three glacial lakes which are used for hydroelectric power generation via a canal system that links the lakes. The basin is an area of climate extremes, low rainfall, high summer temperatures, and snowy winters. The area is predominantly used for pastoral farming, however farming practices are changing and, combined with an increasing population, there is a need to define the groundwater resources to enable sustainable resource management. Little is currently known about the hydrogeological system within the Mackenzie Basin, and what is known is from investigations carried out during the construction of the canal system from 1935 to 1985. There are four glacial formations that overlie Tertiary sequences and Torlesse bedrock. However, due to the glacial processes that have been ongoing over at least the last 300 ka, determining the occurrence and extent of groundwater within the outwash gravels is difficult. It is suggested that the permeability of the formations decreases with depth, therefore horizontal and vertical hydraulic conductivity decrease with depth. A shallow groundwater table is present within the Post Glacial Alluvial Gravels which is recharged directly from fast flowing streams and rivers as well as rainfall. It appears that this shallow system moves rapidly through the system and it is unlikely that the water infiltrates downwards to recharge the deeper groundwater system. It is thought that a deep groundwater system flows preferentially through the Mt John Outwash Gravels, being the second youngest glacial formation. Water chemistry and age dating tracer analysis indicate that the deeper groundwater is over 80 years old and that the groundwater system is recharging slowly. The shallow groundwater in the Post Glacial Alluvial Gravels and within the major fans to the east of the basin is 10 to 20 years in age. Baseline data such as water chemistry, groundwater levels, and surface water gaugings have been collected which can be used for future investigations. More data needs to be collected to create a long term record to further define the hydrogeological system and to determine the best way to manage the resource for long term sustainable use in the future.

The Hudson-James Bay Lowlands (HJBL) are composed of fens and bogs frequently intersected by rivers and punctured by bioherms (ancient reef mounds) rising from bedrock aquifer. The peatlands exist partly due to minimal vertical losses limited by the low hydraulic conductivity (K) of the Tyrrell Sea sediments and small vertical gradients between the surface and bedrock aquifers. The recent development of an open-pit mine; DeBeers Victor Diamond Mine within the HJBL requires dewatering of the regional limestone aquifer to a depth of 200 mbgs. Two major components in assessing the potential impacts of dewatering on the hydrogeological regime and the sensitive peatland ecosystem are: the characteristics and behaviour of the Tyrrell Sea aquitard, and bioherms as potential recharge enhancing features. The Victor Tyrrell Sea (VTS) deposits are clayey silt with low LL, low PI, and no smectite clay minerals. The clay fraction consists of quartz, illite, chlinochlore, and usually calcite. The deposits are normally consolidated with Cc values of 0.08-0.155 and void ratios of 0.52-0.77. The VTS deposits are grey with pockets of black graphite and frequent shells. The K rages from 6.6x10-9 to 4.7x10-8 m/s. GEO-SLOPE™ finite element modeling software was used to investigate the sensitivity of surface drainage and consolidation behaviour in regard to the range of measured VTS parameters. The behaviours were also compared to classic clay aquitard types such as Lake Agassiz and Lake Champlain. Unit thickness, K, and the K modifier function have the greatest impact on the rate and magnitude of consolidation, and vertical drainage of the surface. The K of the underlying till is extremely important because they can be a buffer between the dewatered bedrock aquifer and the VTS. The characteristics of the sediments and the flow regime surrounding three outcropping bioherms which increase vertical drainage are investigated and a conceptual model of flow is proposed. The sediments in profile around bioherms have different levels of stratification but always contain silt and sand units. The hydraulic conditions at eight nested piezometers and the stratigraphy as defined by a series of auger hole profiles was considered to develop a conceptual model. The flow regime presented is of radial flow towards the bioherms enhanced by high K sediments between the peat and bedrock becoming vertical flow when the high K sediments contact vertical channels in the rock. / Thesis (Master, Geological Sciences & Geological Engineering) -- Queen's University, 2013-02-06 14:47:13.582