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Master of Science / Department of Biological and Agricultural Engineering / Naiqian Zhang / A real time wireless, optical sensor network was tested for long-term, remote monitoring of suspended sediment concentrations (SSC) in streams. The sensor and control board assembly was calibrated using a two-stage calibration procedure, including a pre-calibration conducted in the laboratory to adjust the sensitivity of the sensor and a field calibration using grab samples to establish an effective statistical model to predict SSC from the sensor signals. The assembly was installed in three military bases around the United States. These bases were Fort Riley, Kansas; Fort Benning, GA; and Aberdeen Proving Ground, MD. The types of water bodies and watersheds varied greatly among the sites, which allowed the sensor to be tested under versatile conditions for potential widespread use. The results show that the sensor was capable of measuring SSC at each watershed independently. The calibration model developed for each sensor can be used to predict SSC from real-time sensor data. A data processing algorithm was developed to lessen the effect of fouling and clogging on sensor signals, along with eliminating anomalies in the data gathered. The results of this study displayed meaningful prediction data that can be used to estimate SSC in a stream over a long period of time. Information obtained in this study can be used as a launching point for future work and understanding of stream processes.

Sedimentation (erosion, transport, and deposition) is a primary and growing environmental, engineering, and agricultural issue around the world. However, collection of the data needed to develop solutions to sedimentation issues has declined by about three-fourths since 1983. Suspended-sediment surrogates have the potential to obtain sediment data using methods that are more accurate, of higher spatial and temporal resolution, and with less manually intensive, costly, and hazardous methods. The improved quality of sediment data from high-resolution surrogates may inform improved understanding and solutions to environmental, engineering, and agricultural sedimentation problems. The field experiments for this research includ physical samples of suspended sediment collected concurrently with surrogate metrics from instruments including 1.2, 1.5, and 3.0 megahertz frequency acoustic doppler current profilers, a nephelometric turbidity sensor, and a laser-diffraction particle size analyzer. This comprehensive data set was collected over five storms in 2009 and 2010 at Yellow River near Atlanta, Georgia. This research project has proposed, developed, and tested a new method for evaluation of sediment size from theoretical acoustic attenuation; evaluated and further developed recently introduced empirical methods for estimating acoustic attenuation by sediment; found and quantified data mischaracterization issues for laser-diffraction metrics; defined deterministic causes for observed hysteresis and variance in suspended sediment to surrogate relations; compared the accuracy of sediment concentration models and loads for each tested surrogate; and compared sediment surrogate technologies on the basis of reliability and operational considerations.

The monitoring of flood events provide the study of the flow generated during the rains, as well as the production and sediment transport in rural and urban watersheds providing monitoring data for future applications. The work was carried out in a section of Vacacaí Mirim river near the municipality of Restinga Sêca / RS of October 02, 2014 in December 3, 2015 with 16 events monitored with liquid discharge measurement (Q) and solid discharge after occurrence of rainy events. The objective is to perform the temporal assessment of sediment yield and some methods of calculations to estimate sediment transport to the section in the study were quantified solid discharges of the cross section and the characterization of particle sizes of the transported materials. Were determined the solid and liquid discharges for the 2014 period and 2015 in order to evaluate them temporally with the solid and liquid discharges between 2007-2015 using the Pearson correlation coefficient (r) and coefficient of determination (r²).To analyze the results and point out that indirect method of calculation to estimate sediment transport is the most suitable for the current study and compare them with previous studies using the dispersion index (DI) proposed by Aguirre et al. (2004).. The suspended material was shown to be almost all of the solid discharge in river. The granulometric composition of this material is the predominance of silt (58.3%) Sand then (28.4%) and clay (13.4%). For the material bed and drag, there was a predominance of sand, followed by silt and clay. The total solid monthly discharge to the measurement section to 2014-2015 was 117554.62 tons in 15 months evaluated. For the period 2007-2015 the total discharge was 141,039.37 tons/year. The most appropriate methods for the total solid discharge were Einstein's methods modified by Colby and Hembree (1955), Colby (1957), which include the measured sediment concentration data, dispersion index (DI) 0.09 and 2.30 respectively. Predictive methods for overall solid discharge the most appropriate methods were Toffaleti (1969) with value DI = 1.42, Engelund & Hansen (1967) DI = 2.38, Ackers and White (1973) DI = 2.44, Laursen (1958) DI = 4.07 and Yang (1973) DI = 9.42 and unloading solid bed best results were obtained by the methods of Van Rijn (1984) DI = 0.77, Karim (1998), DI = 1.66, Meyer-Peter and Müller (1948) with 6.08 DI. / O monitoramento dos eventos de cheia proporcionam o estudo do escoamento gerado durante as chuvas, assim como, a produção e o transporte de sedimentos em bacias rurais e urbanas propiciando dados de monitoramento para futuras aplicações. O trabalho foi realizado em uma seção do rio Vacacaí Mirim próximo ao munícipio de Restinga Seca/RS, de 02 de outubro de 2014 a 03 de dezembro de 2015 com 16 eventos monitorados, com medição de descarga líquida(Q) e descarga sólida após ocorrência de eventos chuvosos. O objetivo do trabalho é realizar a avaliação temporal da produção de sedimentos e alguns métodos de cálculos para estimar o transporte de sedimentos para a seção em estudo Foram quantificadas as descargas sólidas da seção transversal e a caracterização das granulometrias dos materiais transportados. Determinaram-se as descargas sólidas e líquidas para o período de 2014 e 2015 com o intuito de avalia-las temporalmente com as descargas sólidas e líquidas entre 2007 a 2015 utilizando o índice de correlação de Pearson (r) e coeficiente de determinação (r²). Para analise dos resultados obtidos e apontar qual método indireto de calculo para estimar o transporte de sedimentos é o mais adequado para o atual estudo e compara-los com estudos anteriores com o uso do índice de dispersão (ID) proposto por Aguirre et al. (2004). O material em suspensão demonstrou ser quase totalidade da descarga sólida do rio. A composição granulométrica deste material tem a predominância de silte (58,3%) seguida de areia (28,4 %) e argila (13,4%). Para o material de leito e de arraste, constatou-se a predominância de areia, seguida de silte e argila. A descarga sólida total mensal média até a seção de medição para 2014 a 2015 foi 117.554,62 toneladas e a perda de camada de solo 0,05 mm em 15 meses avaliados. Para o período de 2007 a 2015 a descarga total foi 141.039,37 ton/ano e a perda de camada de solo foi 0,06 mm/ano.Os métodos mais adequados para o cálculo da descarga sólida total foram os métodos de Einstein modicado por Colby e Hembree (1955), Colby (1957), que incluem dados medidos de concentração de sedimentos, com Índice de dispersão(ID) 0,09 e 2,30 respectivamente. Dos métodos preditivos para descarga sólida total os métodos mais adequados foram Toffaleti (1969) com valor de ID = 1,42, Engelund & Hansen (1967) ID = 2,38, Ackers e White (1973) ID = 2,44, Laursen (1958 ) ID = 4,07 e Yang (1973) ID= 9,42 e para descarga sólida de leito os melhores resultados foram obtidos pelos métodos de Van Rijn (1984) ID = 0,77, Karim (1998) com ID = 1,66, Meyer-Peter e Müller (1948) com ID de 6,08.

Made available in DSpace on 2016-12-23T14:04:33Z (GMT). No. of bitstreams: 1 Dissertacao de Andreia Carvalho dos Santos.pdf: 2260427 bytes, checksum: 6e702fa77321abfe2d33e92c7bc60b8f (MD5) Previous issue date: 2011-07-13 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / A Baía de Vitória (ES) abrange um sistema estuarino importante, contendo um dos complexos portuários mais importantes do país. As atividades portuárias associadas à intensa urbanização causam prejuízos ambientais para a região, incluindo constantes dragagens e aterros. A principal fonte de contaminação na região é o lançamento de esgoto da drenagem continental. O presente trabalho caracteriza os sedimentos de alguns pontos da baía quanto à localização, granulometria e toxicidade visando contribuir para a análise da legislação sobre monitoramento do sedimento em eventos de dragagem. Durante a remobilização, o sedimento é ressuspenso juntamente com os contaminantes para a coluna d água podendo gerar impactos tanto no local dragado como no de disposição. Para avaliar a toxicidade do sedimento com diferentes granulometrias foram realizados monitoramentos, incluindo ensaios ecotoxicológicos agudos com a bactéria Vibrio fischeri e crônicos com a microalga Skeletonema costatum. As análises físico-químicas e os testes com Skeletonema costatum foram feitos com elutriato e os testes com Vibrio fischeri com água intersticial. Foram selecionados 9 diferentes pontos de coleta de sedimento com diversos teores de areia e de lama. Os resultados obtidos com os ensaios ecotoxicológicos indicaram correspondência entre a toxicidade do sedimento e a proximidade com as fontes de contaminação. Porém, o mesmo não ocorreu para a relação teor de lama e contaminação. Alguns pontos de coleta, embora o percentual de lama fosse baixo (≤ 10%), apresentaram toxicidade, o que contribui para uma discussão sobre as diretrizes e procedimentos da Resolução Conama 344/04. Sendo assim, foi verificado que não se pode destituir de monitoramento o sedimento de um estuário ou baía apenas pela granulometria - independente do volume a ser dragado - sem se referir à questão da contaminação e da proximidade de fontes de contaminação / The Bay of Vitória (ES, Brazil) comprises an important estuarine system and one of the most significant port complexes in Brazil. Port activities along with intense urbanization are responsible for environmental damages in the area, including constant dredging and landfills. The main source of contamination in the area is sewage dumping from continental drainage. This study characterizes sediments from some points of the bay according to location, granulometry, and toxicity in order to contribute to analyzing the laws regulating sediment monitoring during dredging events. During remobilization, sediment is resuspended with contaminants to the water column, which can cause impacts on both dredged and disposal areas. Sediment toxicity with different grain sizes was assessed through acute ecotoxicological testing with bacterium Vibrio fischeri, and chronic ecotoxicological testing with microalgae Skeletonema costatum. The physical-chemical analyses and tests with Skeletonema costatum were performed through elutriation, and the tests with Vibrio fischeri used interstitial water. Nine (9) different sediment collection points, with varied sand and mud contents, were selected. The results obtained from ecotoxicological testing showed correspondence between sediment toxicity and proximity to contamination sources. However, this was not found for the relation between mud content and contamination. Some collection points presented toxicity despite the fact that mud content was low (≤ 10%). This contributes to the discussion about the guidelines and proceedings in the CONAMA (Brazilian Council for the Environment) Resolution 344/04. We verified that sediments of an estuary or bay cannot be deprived from monitoring based only on grading regardless of the amount being dredged without taking the contamination and proximity to contamination sources into account