Protection of groundwater sources has become an important issue in Canada. Over the last decade many approaches to the protection of groundwater sources have evolved. Some approaches provide qualitative information while others give quantitative values with respect to protection measures. The objective of the thesis is to examine the existing approaches of source water protection (SWP) using a complex geological setting, and introduce new methodologies towards the quantitative measurement of the various steps of SWP. The information obtained from the studies can be used to set up future guidelines for SWP. The first step in SWP is to assess the vulnerability of an aquifer. In this thesis, we compare three approaches for evaluating aquifer vulnerability: the Index Approach (Intrinsic Susceptibility Index, or ISI), the Hydraulic Resistance (HR) Approach (similar to the Aquifer Vulnerability Index, or AVI) and the Travel Time Approach (Surface to Aquifer Advective Time, or SAAT). The ISI approach uses the thickness and vertical hydraulic conductivity of the layers overlying an aquifer, and the vulnerability is expressed as a numerical score which is related to these parameters but is not physically based. The HR approach is physically based, uses the same parameters as ISI with the addition of porosity, and results are in the form of travel time under a unit gradient. SAAT extends the physically based approach by including the unsaturated zone and using the actual downward gradient; results are given in terms of advective travel time from surface to aquifer. These three approaches are compared, using two different aquifer systems. The second step in SWP is the delineation of wellhead protection areas (WHPAs). The WHPA delineates the area within which a source of contamination could have an impact on the well. The actual impact on the well depends not only on the source, but also on the characteristics of the groundwater system. Important considerations include the dimensionality of the system, the uncertainty in the system characteristics, and the physical processes that could affect the impact. The conventional approach is to define different time of travel (TOT) zones based on backward advective particle tracking. An alternative approach is to apply backward advective-dispersive solute transport modelling, in which dispersion can be taken as representing the uncertainty in defining the hydrogeologic characteristics (e.g. hydraulic conductivity) of the aquifer. The outlines of the TOT zones in the backward advective particle tracking approach is obtained by drawing an envelope around the respective tracks, which may require considerable guesswork. In the backward-in-time transport modelling, the outline of the TOT zones are developed using mass balance principles. The third step is the assessment of well vulnerability. Well vulnerability is based on the source-pathway-receptor concept which analyses the transport and fate of the contaminants along its path from the source to the receptor, and the interaction of the well itself with the flow system, and thus determines the actual impact on the well. The impact can be expressed in terms of the contaminant concentration in the well water. The mapping of the impact can be carried out by using a standard advective-dispersive transport model in either a forward-in-time mode (for a known contaminant source) or in a backward-in-time mode (for unknown sources). Thus, the well vulnerability concept goes beyond the conventional approach of WHPA, which is based solely on advective transport, neglecting dispersion and chemical processes. For any known point or non-point time-varying contaminant sources located arbitrarily within the well capture zone, the expected concentration at the well can simply be evaluated by convoluting the source mass with the results of the well vulnerability without further use of the model. Convolution is a well-known and effective superposition method to deal with arbitrary inputs in time and space for linear systems. The information of the contaminant concentration in the well water can be used to quantify the risk of a well becoming contaminated. Risk can be expressed in terms of the exposure value of the contaminant concentration exceeding the allowable limit and the time frame within which the well becomes contaminated. The exposure value can be integrated with the time element to set up a ranking of priorities, or to calculate the investment that must be made today in order to have the required funds available for remediation at the time it becomes necessary. The concept is applied to a well using hypothetical contaminant sources located arbitrarily within the capture zone. Well vulnerability maps can be used as a powerful tool to identify the optimal locations for Beneficial Management Practices (BMPs). A case study addressing the problem of elevated nitrate levels in a drinking water supply well is used to demonstrate the principle. The reduction of nitrate input concentration within the most vulnerable areas shows the largest impact at the well.

<p>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 &ndash / 194 mm or 4 &ndash / 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.</p>

Submitted by Valquíria Barbieri (kikibarbi@hotmail.com) on 2018-04-06T19:22:23Z No. of bitstreams: 1 DISS_2014_Neiva Sales Rodrigues.pdf: 1712321 bytes, checksum: 717e9461616abe5736ab1387a4469bb6 (MD5) / Approved for entry into archive by Jordan (jordanbiblio@gmail.com) on 2018-04-23T18:31:18Z (GMT) No. of bitstreams: 1 DISS_2014_Neiva Sales Rodrigues.pdf: 1712321 bytes, checksum: 717e9461616abe5736ab1387a4469bb6 (MD5) / Made available in DSpace on 2018-04-23T18:31:18Z (GMT). No. of bitstreams: 1 DISS_2014_Neiva Sales Rodrigues.pdf: 1712321 bytes, checksum: 717e9461616abe5736ab1387a4469bb6 (MD5) Previous issue date: 2014-11-25 / CAPES / As atividades geradoras de contaminantes, tendo uso inadequado, podem causar danos irreversíveis às águas subterrâneas. Para contornar esse problema têm sido adotadas, em várias partes do mundo, principalmente nos países desenvolvidos, medidas preventivas, pois uma vez contaminado o aquífero, a sua remediação é muito lenta e dependendo do contaminante, pode durar vários anos. A área de estudo é a cidade de Primavera do Leste - MT e seu entorno, que possui uma população de aproximadamente 55.000 habitantes, e está em crescimento contínuo e elevado, onde o uso indiscriminado do meio físico gera uma grande diversidade de fontes potenciais de contaminação das águas subterrâneas, porém com impacto ainda desconhecido. Na avaliação da vulnerabilidade do Aquífero Bauru foi aplicado o método SI, onde foram usados os seguintes parâmetros: profundidade da água (D), recarga (R) e litologia do aquífero (A), topografia (T), uso e ocupação do solo (LU). Os dados foram processados através de software específico para viabilizar a elaboração do mapa de vulnerabilidade SI. A maior parte da área apresentou valor de nível estático entre 0,5 a 3,5 metros. A litologia obteve apenas uma faixa de classificação, média de arenitos finos, cuja classe (Ar) é 8, multiplicado por 10 e por SIw (0,259) é 20,72. A maior parte da área ficou entre 0 e 0,05% de inclinação topográfica. A área de drenagem fluvial urbana apresentou valores entre 11 e 15 nas classes de uso e ocupação do solo, a área urbana contínua e área urbana descontínua apresentaram valores entre 15 e 19, a área de agricultura (culturas anuais) tiveram os maiores valores, de 19 a 23. As classes de vulnerabilidade variaram de desprezível à moderada, de acordo com a contribuição de cada parâmetro SI. Os resultados desta pesquisa são indispensáveis para a elaboração de um plano de gestão para este aquífero. / Generating activities of contaminants, and improper use can cause irreversible damage to groundwater. To circumvent this problem have been adopted in various parts of the world, especially in developed countries, preventive measures, because once contaminated the aquifer, their remediation is very slow, depending on the contaminant, can last several years. The study area is the town of Primavera do Leste - MT and its surroundings, which has a population of approximately 55,000 inhabitants, and is in continuous and high growth, where the use of physical means discriminated generates a great diversity of potential sources of contamination groundwater, but with unknown impact. In assessing the vulnerability of the aquifer Bauru SI method was applied where the following parameters were used: water depth (D), recharge (R) and lithology of the aquifer (A), topography (T), the use and occupation of land (LU). The data were processed using specific software to enable the preparation of vulnerability SI map. Most of the area, showed static level between 0.5 to 3.5 meters. The lithology obtained only one band classification, average fine sandstones, whose class (Air) is 8 multiplied by 10 and by SIW (0.259) is 20.72. Most of the area was between 0 and 0.05% topographical gradient. The urban area of fluvial drainage had values between 11 and 15 classes of land cover and use, continuous and discontinuous urban area urban area had values between 15 and 19, the area of agriculture (annual crops) had the highest values of 19 to 23. The class of vulnerability ranged from negligible to moderate, according to the SI input of each parameter. The results of this research are essential to the development of a management plan for this aquifer.

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 &ndash; 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