Made available in DSpace on 2015-03-26T13:28:25Z (GMT). No. of bitstreams: 1 texto completo.pdf: 3312573 bytes, checksum: ed584b61ed8559e202f6757198d90e5e (MD5) Previous issue date: 2013-06-21 / Companhia Energética de Minas Gerais / All reservoirs formed by dams are subject to the process of sedimentation. Sediment accumulation reduces reservoir s useful volume and causes modifications in its elevation x area x volume (EAV) curves, which must be periodically updated. In this context, this study aims to evaluate the siltation process in SHP (Small Hydropower Plant) Cachoeirão reservoir and to update its operational data. The methodology consisted of comparing the results obtained before and after the reservoir filling, using Digital Elevation Model (DEM) and the fuction TIN (Triangulated irregular network), allowing to generate the EAV curves and to identify the total volumes of sediment deposited in the reservoir and the sediment level in the water intake. From this comparison, it was determined that, during 13 years of operation, the volume of sediment deposited on Cachoeirão s lake was equal to 0.866 hm3. This value represents a reduction of 15.9% in the original storage capacity of the reservoir. The softwares Sediment and Dposit were also used to assess the siltation process in SHP Cachoeirão and their results indicated an underestimation of the deposited sediments volume, in comparison to field results. The sediments accumulated at the bottom of the reservoir presented a variable grain size distribution, ranging from sand size observed in particles deposited closer to the start of backwater, until clay size, observed in particles deposited near to the dam axis. The study also concluded that the expected useful lifetime of the reservoir should not be achieved, unless preventive measures are taken to reduce the amount of sediment that enters the reservoir. / Reservatórios formados por barragens estão sujeitos ao processo de assoreamento. O acúmulo de sedimentos reduz o volume útil do reservatório e provoca alterações em suas curvas cota x área x volume (CAV), que devem ser atualizadas periodicamente. Nesse contexto, este estudo objetivou avaliar o processo de assoreamento no reservatório da PCH Cachoeirão e atualizar os seus dados operacionais. A metodologia empregada consistiu na comparação dos resultados obtidos antes e depois do enchimento do reservatório, com a utilização de Modelo Digital de Elevação (MDE) e função TIN (Triangulated irregular network), que possibilitou gerar as CAV, e identificar volumes de sedimentos totais e níveis de sedimentos na tomada d ́água. A partir dessa comparação, determinou-se que em 13 anos de operação o volume de sedimento depositado no lago da PCH Cachoeirão foi de 0,866 hm3. Esse valor representa uma redução de 15,9% na capacidade de armazenamento original do reservatório. Os softwares Sediment e Dposit também foram utilizados para avaliar o assoreamento da PCH Cachoeirão e seus resultados indicaram uma subestimativa do volume de sedimentos depositado, em relação aos resultados observados em campo. Os sedimentos acumulados no fundo do reservatório apresentaram distribuição granulométrica variável, desde partículas na fração areia, depositadas próximas ao início do remanso, até partículas na fração argila, depositadas próximas ao eixo da barragem. O estudo permitiu concluir que a vida útil esperada para o reservatório não deverá ser alcançada se medidas preventivas, que reduzam a quantidade de sedimentos que adentra o reservatório, não forem tomadas.

nÃo hà / O Brasil possui um grande volume de Ãgua doce, porÃm a RegiÃo Nordeste e o Estado do Cearà sofrem pela escassez deste recurso. Diante deste quadro muitos rios desta regiÃo foram barrados para a construÃÃo de reservatÃrios. Inserido neste contexto està o aÃude Santo AnastÃcio (ASA), objeto desta pesquisa, localizado em Fortaleza-CearÃ. O ASA està sofrendo progressivo processo de perda da qualidade e da profundidade de suas Ãguas, principalmente em funÃÃo das aÃÃes antrÃpicas. Assim, esse trabalho teve como objetivo diagnosticar a evoluÃÃo da perda dessa qualidade, por meio de anÃlises fÃsicas, quÃmicas e biolÃgicas, alÃm de calcular o Ãndice de qualidade das Ãguas (IQA) do aÃude, avaliar o nÃvel de eutrofizaÃÃo e de assoreamento e estudar a variabilidade espacial e temporal dos seus parÃmetros limnolÃgicos. Todos os mÃtodos de anÃlise utilizados foram baseados na 21 ediÃÃo do âStandard methods for the examination of water and waterwaste â APHA-AWWA-WPCFâ. De acordo com os resultados, pode-se concluir que alguns dos parÃmetros analisados, entre eles OD, fÃsforo total e DBO, estÃo em desacordo com os padrÃes estabelecidos para Ãgua doce, classe 3, pela ResoluÃÃo CONAMA n 357, na qual o ASA foi classificado, de acordo com seus usos preponderantes. Isto significa que esse corpo dâÃgua se encontra imprÃprio para as finalidades para as quais ele se destina atualmente. A avaliaÃÃo desse corpo hÃdrico apontou para baixa qualidade das suas Ãguas, segundo o cÃlculo do IQA, que oscila entre bom e ruim, com agravamento na qualidade no ponto 1, que à a regiÃo do aÃude prÃxima à comunidade que reside no seu entorno. Com relaÃÃo ao seu nÃvel de eutrofizaÃÃo, ele foi classificado como hipereutrÃfico, classificaÃÃo mais elevada no processo de envelhecimento artificial. Quanto à variaÃÃo temporal dos parÃmetros analisados, pode-se concluir que houve sazonalidade, com influÃncia do clima local. Esse fato foi observado por meio do estudo das correlaÃÃes entre os fatores climÃticos no teste de Tukey e ratificado pela anÃlise de componentes principais (PCA). Com relaÃÃo à variaÃÃo espacial, ela nÃo foi observada na maioria das variÃveis, com exceÃÃo do OD, que mostrou heterogeneidade no ponto 1, de acordo com o teste de Tukey. / Brazil has a large quantity of freshwater, but the Northeast Region and state of Cearà suffer scarcity of this resource. In function of this, many rivers were barred to build reservoirs. Within this context, there is the Santo AnastÃcio dam (ASA), the object of this research, located in Fortaleza-CearÃ. ASA is suffering progressive losses in the quality and depth of waters, mainly due to human actions. Thus, this study aimed to diagnose the evolution of this degradation by physical, chemical and biological analysis, as well as to calculate the water quality index (IQA) for ASA, to evaluate eutrophication and siltation levels and to study the spatial and temporal variability of their limnological parameters. All methods used here were based on the 21st edition of Standard methods for the examination of water and waterwaste - APHA-AWWA-WPCF. By the results, it was possible to conclude that some of the analysed parameters, including OD, total phosphorus and BOD, were evaluated against the established standards for freshwater, class 3, by âResoluÃÃo CONAMA nÂ357â, in which ASA was classified according to its predominant uses. This means that this reservoir is unfit for the purposes for which it is currently used. The results indicated a low quality of the waters, according to IQA, which oscillated between good and bad, with deterioration in quality, at the point 1, which is the region of ASA dam near the community that resides in its surroundings. About the level of eutrophication, it was classified as hypertrophic, higher ranking in artificial aging process. Regarding the temporal variation of the parameters, it can be concluded that there was seasonal, with the influence of local climate. This fact was observed by the study of correlations among the climatic factors using Tukeyâs test and ratified by Principal Component Analysis (PCA). In relation to spatial variation, it was not observed in most variables, except the OD, that exhibited heterogeneity at the point 1, according to Tukeyâs test.

FundaÃÃo Cearense de Apoio ao Desenvolvimento Cientifico e TecnolÃgico / Practical problems related to water resources and the need for resolution of these was what drove the hydrological modeling, since understanding of the hydrological behavior of the basin was needed. So, this research was conducted to assess, through hydrossedimentological modeling, the behavior of a semiarid meso scale watershed as well as its water availability. The study area was the Madalena Representative Basin, Federal State of CearÃ, with 124kmÂ. Rainfall, accumulated volume and sedimentation in two reservoirs were monitored. The WASA-SED (Model of Water Availability in Semi-Arid Environments Sediment Dynamics with Component) and VYELAS (Volume-Yield Elasticity) models were used in the evaluation. Some conclusions could be obtained from the results: i) Continuous monitoring of hydrological variables in watersheds of the Brazilian semiarid is necessary because the scarcity of data makes it difficult to analyze the performance of hydrological models, ii) Sedimentation measurements in reservoirs is essential for validating of sedimentological routines of model for evaluation of long periods, iii) The soil parameters are determinant in the quality of the results and details of the parameterization significantly improves the performance of the WASA model, iv) The predominance of drought scenario for the next years must affect water supply due to the low volume currently accumulated in the reservoir, v) Water availability of the strategic reservoir of the basin (Marengo reservoir) in extreme years of low rainfall, for 90% reliability yield,is 96% lower than the availability expected for regular years. / Problemas prÃticos relacionados aos recursos hÃdricos e a necessidade de resoluÃÃo desses foi o que impulsionou a modelagem hidrolÃgica, pois uma melhor compreensÃo do comportamento hidrolÃgico da bacia hidrogrÃfica se fez necessÃria. Assim esta pesquisa foi conduzida com o objetivo de avaliar, por meio da modelagem hidrossedimentolÃgica, o comportamento de uma bacia hidrogrÃfica de meso-escala no semiÃrido, assim como sua disponibilidade hÃdrica. A Ãrea foco do estudo foi a Bacia Representativa de Madalena, CearÃ, com 124kmÂ. Os modelos WASA-SED (Model of Water Availability in Semi-Arid Environments with Sediment Dynamics Component) e VYELAS (Volume-Yield Elasticity) foram utilizados na avaliaÃÃo. Algumas conclusÃes puderam ser constatadas a partir dos resultados obtidos: i) O monitoramento contÃnuo das variÃveis hidrolÃgicas em bacias hidrogrÃficas do semiÃrido se faz necessÃrio, pois a insuficiÃncia de dados dificulta a anÃlise do desempenho de modelos hidrolÃgicos; ii) A quantificaÃÃo do assoreamento em reservatÃrios à essencial para a validaÃÃo de rotinas sedimentolÃgicas do modelo para longos perÃodos de avaliaÃÃo; iii) Os parÃmetros do solo sÃo determinantes na qualidade dos resultados e o detalhamento da parametrizaÃÃo melhora sensivelmente o desempenho do modelo WASA; iv) O predomÃnio do cenÃrio de estiagem para os prÃximos anos compromete o abastecimento devido ao baixo volume acumulado atualmente no reservatÃrio; v) A disponibilidade hÃdrica do reservatÃrio estratÃgico da bacia (Marengo) em anos extremos de baixa pluviometria, para uma vazÃo com 90% de garantia, à 96% inferior à disponibilidade para os anos mÃdios.

O processo de sedimentação em reservatórios gera várias conseqüências, dentre elas, o impacto acumulativo da perda de capacidade de armazenamento destes. Este fato faz com que, dependendo dos usos, eles percam a sua funcionalidade tal como a capacidade de regularização de vazão. Tais efeitos não afetam somente uma única atividade econômica que venha a existir nesses reservatórios. Grande parte do modelo econômico que é sustentado pelos usos nestes é afetado. A sedimentação é um processo que não se consegue resolver totalmente, cabendo somente a utilização de técnicas adequadas de manejo da bacia de contribuição do reservatório, reduzindo assim o assoreamento. A presente pesquisa teve como base informações coletadas no reservatório da UHE de Três Irmãos SP, sendo tais informações provenientes de cartas topográficas, estações de monitoramento de chuva, imagens de satélites e campanhas de batimetria no reservatório em estudo. Assim obteve-se que o reservatório está com aproximadamente 6,73% do seu volume assoreado, com uma taxa anual media de assoreamento de 0,4%, se mantendo abaixo da média brasileira e mundial, que é de respectivamente de 0,5% e 1%. / The sedimentation process in reservoirs brings some consequences, among them, the cumulative impact on lacking of the storage capacity of those reservoirs. Depending on the uses of those reservoirs, they may lose their capability of flow regularization. Such effects not only affect one kind of economical activity that may exist upon these reservoirs. A considerable part of the economical model that is supported by those uses is also affected. The sedimentation is a process that can\'t be completely solved, unless the correct use of suitable techniques of management of the contribution basin of the reservoir can reduce the siltation. This research has its foundation on the collected information on the Três Irmãos hydroelectric power plant reservoir, consisting of topographic maps, rain monitoring checkpoints, satellite images and bathymetri campaigns on that reservoir. Thus, it was concluded that the reservoir has approximately 6,73% of its volume silted, and also has a annual average rate of siltation of 0,4%, below the brazilian and world average, 0,5% and 1%, respectively.

The Odlezelské Lake is a natural, landslide-dammed lake in western Bohemia. Its lake basin is silting intensely and its volume decreases; it will be completely silted in the future. This work aims to evaluate the siltation of the lake primarily by evaluating the suspended load regime of its tributaries and comparison with data from bathymetric measurements. Within this work, data from the station network of the Department of Physical Geography of the Faculty of Science of the Charles University were used, which was statistically processed in order to describe the hydrological and suspended load regime. In addition, flow speeds in the inflow part of the lake were measured during two precipitation-runoff events using ADCP. The results show that most of the suspended load is transported during flood episodes, in contrast to the runoff, there is a significant interannual variability in the suspended load regime. Oppositely, the comparison of the suspended load regime and the bathymetric data proved as impossible due to a high sensitivity of the data.

<p> Effects of siltation were measured by determination of growth rates through x-radiography and trapped clastics sediments through coral sample decalcification. Results show an increase in growth rate with an increase in suspended particulate matter. This is attributed to an increase in nutrient levels with increased SPM values.</p> <p> Support of algal banding being an annual indicator was given by comparison of x-radiographs to actual coral slabs.</p> <p> Observation of radiographs reveal an offshore trend in regard to the distinctiveness of annual banding, with the bands being less obvious on outer shelf corals.</p> <p> Large variations in growth rates found within the sample population as a whole, as well as intra-reef samples reveal the limited applications to which these determinations can be used.</p> / Thesis / Bachelor of Science (BSc)

The presence of fine muddy sediment (grain size < 0.1 mm) in streams has many impacts on the fluvial system and those relying on it, both humans and aquatic biota. Previously, fine sediment was considered a washload and has been ignored in transport models. More recently, it has been treated as being transported once the surface gravel layer that stores it is able to be mobilized. We propose that the surface layer need not be mobilized in order for muddy sediment to travel through the fluvial system in a series of erosive and depositional events. Our first study uses a new in situ device to show how mud entrainment from immobile gravel beds behaves cohesionlessly and can be modeled using the framework of classic sand-based models modified to account for hiding effects present in the stream bed. It also provides a method to predict how deep into the surface layer of gravel entrainment of fine sediment will occur given flow and stream bed characteristics. The second study investigates the primary pathway that fine sediment is traveling to get captured within bluehead chub fish nests. It was determined that more deposition of mud occurred in the upstream half of the nest concluding that the primary pathway was hyporheic pumping through the nest. Capture efficiencies of the nests were also found to increase as the length of nests increased. Both of these studies provide supporting evidence in the need to transition modeling fine sediment transport as a series of deposition and resuspension. / Master of Science / Fine muddy sediment (grain size < 0.1 mm) is present in natural streams and has many impacts on the stream system and those relying on it, including humans, plants, animals, and other organisms in the ecosystem. Previously, fine sediment was treated as being too small to consider in models that aid in understanding how a stream transports sediment. This is because small sediment stays suspended in the water column more easily than larger sediment. Therefore, it was just assumed to pass through the system and never deposit into the stream bed. However, in nature we observe large quantities of fine sediment being stored within the stream bed. More recently, it has been assumed that the sediment that does deposit will be transported once the surface gravel layer that stores it is able to be mobilized. That is, the surface gravel layer shields the fine sediment trapped between it and that the mud will stay put until that gravel is moved. We propose that the surface layer need not be mobilized for muddy sediment to travel through the fluvial system in a series of erosive and depositional events. Our first study uses a new device that forces erosion of mud to show how mud entrainment, or the process of how a fluid picks something up and carries it, from immobile gravel beds can be modeled using the framework of classic sand-based entrainment models modified to account for hiding effects, or protection against entrainment of a smaller sediment by a larger sediment shielding it, present in the stream bed. It also provides a method to predict how deep into the surface layer of gravel that fine sediment will be eroded given flow and stream bed characteristics. This is beneficial in estimating the amount of sediment that will be eroded during a given storm event. The second study investigates the primary pathway that fine sediment is traveling to get captured within bluehead chub gravel fish nests used for spawning their eggs and reproducing. It was determined that more deposition of mud occurred in the upstream half of the nest. This leads us to believe that the primary pathway of sediment traveling through the nest was hyporheic pumping through the nest, or the process of water flowing down through the surface layers of sediment in the stream bed. Capture efficiencies, or the ratio of how much of the sediment that traveled through the nest was captured, of the nests were also found to increase as the length of nests in the downstream direction increased. Both of these studies provide supporting evidence in the need to transition modeling fine sediment transport as a series of deposition and resuspension.

Condições pedológicas, pluviosidade, alterações no uso e ocupação do solo, práticas de manejo de culturas e de preservação interferem diretamente na geração de sedimentos e na taxa de erosão. Em uma bacia hidrográfica esta geração de sedimentos excessiva pode resultar em problemas como o assoreamento dos corpos de água e de reservatórios. Nos reservatórios esta deposição de sedimentos pode representar perda de volume de reservação, promovida pelos sedimentos depositados no fundo da barragem. Com o tempo esta perda poderá vir a representar comprometimento da disponibilidade hídrica para irrigação, para o consumo humano, e para geração de energia. As obras de dragagem destes sedimentos são muito caras e resolvem somente os sintomas do problema e não suas causas. Desta forma as quantificações desse assoreamento e de seus deflagradores se mostram necessárias para o planejamento e gestão de recursos hídricos. A presente pesquisa se propõe a avaliar a aplicabilidade do modelo SWAT (Soil Water Assessment Tool) como ferramenta de estimativa de geração de sedimentos para reservatórios avaliando seus resultados, suas potencialidades e fragilidades para as condições locais e sugerir futuras pesquisas e/ou modificações no modelo. O modelo que foi desenvolvido originalmente pelo USDA (United States Departmente of Agriculture) para avaliar erosão e balanço hídrico de bacias hidrográficas, conta com um vasto número de aplicações no mundo, documentação e usuários. A área a ser estuda é bacia do reservatório do Lobo, que possuí uma área aproximada de 227 km² e localizado no município de Itirapina e de Brotas. Atualmente o reservatório é utilizado tanto para geração energética e como atração turística local. Dois cenários de simulação foram selecionados: Cenário 1 de 1977 até 1985 e Cenário 2 de 1996 até 2006. Para realizar as simulações foram utilizados a versão ArcSWAT 2005 version2.34 para realizar as simulações e o SWAT-CUP 4.3.1 para calibração.Os dados de entrada do modelo são: dados de chuvas e vazão diários obtidos da ANA (Agência Nacional das Águas), cartas de levantametno pedológico e cartas de uso e ocupação obtidas a partir de imagens CBERS e LANDSAT. Após calibração utilizando SUFI2 obteve-se o aporte de sedimentos na barragem para os dois cenários. Os resultados do primeiro cenário apresentaram influência negativa de dados inconsistentes de dados de vazão utilizados e limitações observadas na discretização do modelo nas representações do mosaico de uso e ocupação muito fragmentado para este cenário. O segundo cenário, no entanto obteve resultados satisfatórios comprovando a capacidade do modelo como ferramenta de avaliação de geração e aporte de sedimento em reservatórios. / The sediment yield and erosion rates are directly affected by pedologic conditions, precipitation, land and use changes, management and soil preservation practices. Excessive sediment yield in a watershed could result in difficulties caused by siltation processes in rivers and reservoirs. Sediment deposition at the bottom of reservoirs and dams may result in volume loss. In time such loss could become impairment of water availability for irrigation, human consumption and power generation. Sediment dredging is an expensive solution that will address only the symptoms and not the causes of the issue. Therefore assessing the amount of sediment and their causes is required for Water Resources Management and Planning. The present research aims to evaluate the applicability of the SWAT (Soil and Water Assessment Tool) as sediment generation and contribution estimation tool for reservoirs evaluating the results, assessing the model strengths and weakness for the local contitions and make sugestions for future research and/or model modifications. Originally developed by the USDA (United States Department of agriculture) to assess erosion and water balance of watersheds, this model has a large number of users, available documentation and registered applications across the world. The study area, with an approximate area of 227 km² is the Lobo reservoir watershed, located at the municipalities of Itirapina and Brotas. The reservoir is currently used for hydropower generation and as a tourist attraction. Two simulation scenarios were chosen: Scenario 1from 1977 to 1985 and Scenario 2 from 1996 until 2006. To perform the simulations the ArcSWAT 2005 version 2.34 was selected and the SWAT-CUP 4.3.1 for the calibration. The data input was: daily precipitation and discharge flow datasets from ANA (Agência Nacional das Águas), pedological survey chats and land use charts obtained from CBERS and LANDSAT imagery. After calibration using SUFI2, sediment yield and contribution at the dam was obtained for both scenarios. The first scenario results showed negative effects caused by inconsistent input data flow and limitations regarding model discretization on the model representation of highly fragmented land use. The second scenario, however achieved satisfactory results demonstrating the model ability as sediment yield and contribution in reservoir evaluation tool.

A qualidade ambiental de um corpo d\'água é resultado da situação de sua bacia de drenagem, de modo que as transformações que ocorrem no solo do entorno provocam mudanças significativas no ambiente aquático. Por isto, cada vez mais se trabalha com conceito de manejo integrado dos ambientes. Desta forma, o conhecimento dos processos de geração, transporte e deposição de sedimentos, por serem fontes de sólidos, nutrientes e contaminantes ao corpo d\'água, é de vital importância para a conservação, desenvolvimento e manejo integrado dos recursos hídricos. Neste sentido, essa dissertação apresenta um estudo a respeito da exportação e deposição de sólidos e nutrientes na sub-bacia do Ribeirão das Cruzes, no município de Santo Antônio do Aracanguá, SP, na Unidade de Gerenciamento de Recursos Hídricos do Baixo Tietê (UGRHI - 19). Esse corpo d\'água foi subdividido em compartimentos e analisado por transectos, ou seja, eixos transversais ao fluxo, sendo que experimentos envolvendo instalação de câmaras de sedimentação, coleta de sedimentos de fundo e medições de vazão foram conduzidos em dois períodos hidrológicos distintos: um em janeiro, durante a estação chuvosa, e outro em agosto, durante a estação seca. A taxa máxima de deposição de sólidos suspensos foi de 62,40 g/m² dia durante a Estação Chuvosa, e de 37,29 g/m² dia, durante a Estação seca. Ainda, a taxa média de deposição de nitrogênio total Kjeldahl foi de 0,53 e 2,02 g/m² dia e a de fósforo total foi de 139,67 e 103,89 mg/m² dia, durante as Estações Chuvosa e Seca, respectivamente. Quanto às taxas de exportação, para sólidos suspensos foram observadas médias de 2328,44 e 725,96 ton/dia, de nitrogênio total Kjeldahl foram de 121,41 e 299,84 ton/dia e para fósforo total foram de 14,86 e 10,05 ton/dia, durante as Estações Chuvosa e Seca, respectivamente. Os resultados obtidos, comparados a outros estudos em ambientes similares, revelam altas taxas de deposição e exportação de sólidos e nutrientes, demonstrando, desta forma, a incidência dos processos de eutrofização e assoreamento do recurso hídrico, bem como a expressão dos impactos provenientes do uso e ocupação do solo do entorno, capaz de influenciar na qualidade da água do ambiente. / The environmental quality of waterbody is the result of the situation of its drainage basin, so that the transformations that occur on the soils surrounding cause significant changes in the aquatic environment. Therefore, each time more has been increasing the works with the concept of integrated management of environments. Thus, the knowledge about the processes of generation, transport and deposition of sediments, because they are sources of solids, nutrients and contaminants to waterbody, is extremely important for the conservation, development and integrated management of water resources. In this way, this dissertation presents a study concerning the deposition and export of solids and nutrients in the Ribeirão das Cruzes sub-basin, in Santo Antônio do Aracanguá city, SP, in Baixo Tietê Water Resources Management Unit (WRMU - 19). This waterbody was divided into compartments and analyzed by transects, which are transverse axes to the flow, and experiments involving installation of sedimentation traps, collect of bottom sediments and flow measurements were carried out in two distinct hydrological periods: one in January during the rainy season, and another in August, during the dry season. The maximum suspended solids deposition rate were 62.40 g/m² day during the rainy season, and 37.29 g/m² day during the dry season. So, the average rate of nitrogen deposition were 0.53 and 2.02 g/m² day, and the rate of phosphorus were 139.67 and 103.89 mg/m² day, during the rainy and dry seasons, respectively. As for exportation rates, the average rates found of suspended solids were 725.96 and 2328.44 ton/day, the rates of nitrogen were 121.41 and 299.84 ton/day, the rates of phosphorus were 14.86 and 10.05 ton/day, during the rainy and dry seasons, respectively. The results obtained, when compared to other studies in similar environments, show high rates of solids and nutrients deposition and export, demonstrating, this way, the incidence of eutrophication processes and siltation of the water resources, as well as the expression of impacts from the landuse, able to influence the water quality.

A field survey was undertaken in Central Kalimantan, Indonesia (Borneo) to assess the extent and practices of Artisanal and Small-scale Gold Mining (ASGM), and to measure sediment and mercury flows in the provinces’ rivers. More than forty mining operations were visited in six of the provinces largest river basins during June, July and August of 2008. Based on the survey results, this thesis estimates that 43,000 small-scale gold miners in Central Kalimantan produced 13.3 tonnes of gold in 2008 (426,000 troy ounces - ozt) worth approximately 362 million CAD (based on 2008 international gold price of 850 CAD/ozt). Mercury use was ubiquitous for leaching gold from ores in the province. Approximately 65.3 tonnes was used for this purpose in 2008, with the majority of consumption- 80% by whole-ore amalgamation operations exploiting hard-rock deposits, but producing only 13% of the gold. These estimates have been interpolated using (i) measurements and detailed observations at more than forty ASGM operations surveyed in five different regencies; (ii) numerous interviews with miners, gold shops owners and officials across these regencies; and (iii) mapping of ASGM operations using satellite imagery. Hydraulic mining methods mobilize enormous volumes of sediment and native sediment-bound mercury. Sediment and mercury fluxes associated with ASGM activities were estimated based on a river sediment sampling campaign carried out in conjunction with the ASGM survey, and on subsequent modelling of river sediment transport. On streams and tributaries, mining activities increased sediment transport by factors between 100 and 1500, resulting in a net doubling of sediment loads on large first order river channels, on which the effects of mining are diluted in space and time by channels without mining. Particulate mercury flux sampled on six of Central Kalimantan’s largest river channels averaged 60ng/L ±33%, a high figure relative to most global rivers, despite average suspended sediment concentrations of only 75mg/L ±58%. Based on a hydrological and sediment transport model, 19.4 tonnes of mercury (±30%) transits these river systems annually, dominantly transported as suspended sediment load (95%), with the remaining 5% transported as bedload. Acute mercury exposure by inhalation during the burning of mercury-gold amalgam represents an important health concern at ASGM camps and gold shops. In relation to mercury, sector improvements should focus on eradicating whole ore amalgamation, and open burning of amalgam. Eliminating whole ore amalgamation requires technological improvements at the gold liberation (crushing and milling) and concentration stages of ore processing. Elimination of open-air burning can be achieved through education, and the use of retorts, fumehoods, and mercury re-activation cells– each of these basic technologies provide mercury users with economic incentives by reducing mercury consumption. / Graduate