Dissertations / Theses on the topic 'Water quality state estimation'
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Sinha, Sumit. "Parameter estimation and auto-calibration of the STREAM-C model." Master's thesis, Mississippi State : Mississippi State University, 2005. http://library.msstate.edu/content/templates/?a=72.
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Farzanehrafat, Ali. "Power Quality State Estimation." Thesis, University of Canterbury. Electrical and Computer Engineering, 2014. http://hdl.handle.net/10092/9830.
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Traditional state estimation whereby the state of the system is assessed based on a limited number of measurements is a well established tool for steady-state situations where the frequency of the system is 50 Hz. Previous contributions have looked at extending this concept to the power quality area. This area of research is called Power Quality State Estimation (PQSE) and represents a class of techniques. Under the umbrella of PQSE, the main contribution of this work is taking Transient State Estimation (TSE) on step further. A new three-phase formulation for TSE using the Numerical Integrator Substitution (NIS) will be detailed. NIS approach, also known as Dommel's method, gives a numerical solution to describe the transient behaviour of a dynamic system at discrete time points. The new transient state estimator is implemented and verified by applying the proposed algorithm to a real distribution test system. It's performance and accuracy are investigated in presence of measurement noise, background harmonics, multiple faults, etc. The conducted study has shown this technique has a great potential.
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Hamza, Sarah. "State of water quality management in Egypt." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0008/MQ42329.pdf.
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Vaschenko, Nataliya. "Quality and ecological state of ground water." Thesis, Видавництво СумДУ, 2005. http://essuir.sumdu.edu.ua/handle/123456789/13585.
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Roz, Evan Phillips. "Water quality modeling and rainfall estimation: a data driven approach." Thesis, University of Iowa, 2011. https://ir.uiowa.edu/etd/1258.
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Water is vital to man and its quality it a serious topic of concern. Addressing sustainability issues requires new understanding of water quality and water transport. Past research in hydrology has focused primarily on physics-based models to explain hydrological transport and water quality processes. The widespread use of in situ hydrological instrumentation has provided researchers a wealth of data to use for analysis and therefore use of data mining for data-driven modeling is warranted. In fact, this relatively new field of hydroinformatics makes use of the vast data collection and communication networks that are prevalent in the field of hydrology. In this Thesis, a data-driven approach for analyzing water quality is introduced. Improvements in the data collection of information system allow collection of large volumes of data. Although improvements in data collection systems have given researchers sufficient information about various systems, they must be used in conjunction with novel data-mining algorithms to build models and recognize patterns in large data sets. Since the mid 1990's, data mining has been successful used for model extraction and describing various phenomena of interest.
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DeChant, Caleb Matthew. "Hydrologic Data Assimilation: State Estimation and Model Calibration." PDXScholar, 2010. https://pdxscholar.library.pdx.edu/open_access_etds/172.
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This thesis is a combination of two separate studies which examine hydrologic data assimilation techniques: 1) to determine the applicability of assimilation of remotely sensed data in operational models and 2) to compare the effectiveness of assimilation and other calibration techniques. The first study examines the ability of Data Assimilation of remotely sensed microwave radiance data to improve snow water equivalent prediction, and ultimately operational streamflow forecasts. Operational streamflow forecasts in the National Weather Service River Forecast Center are produced with a coupled SNOW17 (snow model) and SACramento Soil Moisture Accounting (SAC-SMA) model. A comparison of two assimilation techniques, the Ensemble Kalman Filter (EnKF) and the Particle Filter (PF), is made using a coupled SNOW17 and the Microwave Emission Model for Layered Snowpack model to assimilate microwave radiance data. Microwave radiance data, in the form of brightness temperature (TB), is gathered from the Advanced Microwave Scanning Radiometer-Earth Observing System at the 36.5GHz channel. SWE prediction is validated in a synthetic experiment. The distribution of snowmelt from an experiment with real data is then used to run the SAC-SMA model. Several scenarios on state or joint state-parameter updating with TB data assimilation to SNOW-17 and SAC-SMA models were analyzed, and the results show potential benefit for operational streamflow forecasting. The second study compares the effectiveness of different calibration techniques in hydrologic modeling. Currently, the most commonly used methods for hydrologic model calibration are global optimization techniques. While these techniques have become very efficient and effective in optimizing the complicated parameter space of hydrologic models, the uncertainty with respect to parameters is ignored. This has led to recent research looking into Bayesian Inference through Monte Carlo methods to analyze the ability to calibrate models and represent the uncertainty in relation to the parameters. Research has recently been performed in filtering and Markov Chain Monte Carlo (MCMC) techniques for optimization of hydrologic models. At this point, a comparison of the effectiveness of global optimization, filtering and MCMC techniques has yet to be reported in the hydrologic modeling community. This study compares global optimization, MCMC, the PF, the Particle Smoother, the EnKF and the Ensemble Kalman Smoother for the purpose of parameter estimation in both the HyMod and SAC-SMA hydrologic models.
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Frederick, Brent Ray. "Magnesium supplementation through drinking water to improve pork quality." NCSU, 2003. http://www.lib.ncsu.edu/theses/available/etd-05162003-134628/.
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Four experiments were conducted to investigate the effect of short term magnesium supplementation through drinking water prior to harvest on pork quality of pigs. Two days of magnesium supplementation (experiment 1) appeared optimal to improved pork quality. Older, slower growing pigs produced higher pork quality than younger faster growing pigs; however, magnesium supplementation had no effect (experiment 2). The presence of the Halothane and to a greater extent the Rendement Napole mutation reduced the quality of pork (experiment 3). Furthermore, pigs with both mutations had poorer pork quality than pigs with one mutation. Magnesium supplementation reduced pork quality when supplemented to pigs with the Halothane mutation. Pork quality was not affected when dose of magnesium supplemented in the water was altered (experiment 4). Although plasma magnesium was increased by magnesium supplementation, muscle magnesium was not affected. Overall, magnesium supplementation through drinking water for 2 days prior to harvest does not appear to be a method to consistently improve pork quality.
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Tamagnini, Filippo. "EKF based State Estimation in a CFI Copolymerization Reactor including Polymer Quality Information." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2020. http://amslaurea.unibo.it/20235/.
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State estimation is an integral part of modern control techniques, as it allows to characterize the state information of complex plants based on a limited number of measurements and the knowledge of the process model. The benefit is twofold: on one hand it has the potential to rationalize the number of measurements required to monitor the plant, thus reducing costs, on the other hand it enables to extract information about variables that have an effect on the system but would otherwise be inaccessible to direct measurement.
The scope of this thesis is to design a state estimator for a tubular copolymerization reactor, with the aim to provide the full state information of the plant and to characterize the quality of the product.
Due to the fact that, with the existing set of measurements, only a small number of state variables can be observed, a new differential pressure sensor is installed in the plant to provide the missing information, and a model for the pressure measurement is developed.
Following, the state estimation problem is approached rigorously and a comprehensive method for analyzing, tuning and implementing the state estimator is assembled from scientific literature, using a variety of tools from graph theory, linear observability theory and matrix algebra. Data reduction and visualization techniques are also employed to make sense of high dimensional information.
The proposed method is then tested in simulations to assess the effect of the tuning parameters and measured set on the estimator performance during initialization and in case of estimation with plant-model mismatch.
Finally, the state estimator is tested with plant data.
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Sahinci, Erin. "Optimal estimation of discrete fault probabilities using a stochastic state model." Diss., Georgia Institute of Technology, 1998. http://hdl.handle.net/1853/16888.
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Schneider, Seth J. "Hydrothermal and water quality modelng for evaluation of Ashumet Pond trophic state." Thesis, Massachusetts Institute of Technology, 1997. http://hdl.handle.net/1721.1/42637.
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Filho, Aldeney Andrade Soares. "Phytoplankton Community and Water Quality, Aquatic Ecosystems in the State of CearÃ." Universidade Federal do CearÃ, 2010. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=7761.
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RESUMO A Ãgua constitui o recurso de maior importÃncia para o homem, no entanto parece nÃo existir nenhuma preocupaÃÃo do ser humano em preservÃ-la, uma vez que as atividades diÃrias estÃo prejudicando cada vez mais, a qualidade deste recurso. Este trabalho teve por objetivo analisar a estrutura da comunidade fitoplanctÃnica e a qualidade da Ãgua de ecossistemas aquÃticos do Estado do Cearà (Brasil). Foram realizadas coletas mensais nas estaÃÃes chuvosa e seca, entre 2004 e 2007, nos seguintes ecossistemas: estuÃrios dos rios CauÃpe, MundaÃ, Cearà e Malcozinhado; lagoas de Jijoca, PecÃm, Uruaà e Maraponga; bicas do Ipu e das AndrÃas e aÃudes Favelas, da Corte e Campus do Itaperi. Os resultados mostraram mudanÃa significativa na estrutura da comunidade fitoplanctÃnica, influenciada principalmente pelos nÃveis de precipitaÃÃes pluviomÃtricas. As Bacillariophyceae foram predominantes nos ecossistemas analisados, exceto nos aÃudes Favelas, da Corte e do Campus do Itaperi, que apresentaram elevados nÃveis de eutrofizaÃÃo, com dominÃncia de Cyanophyceae, Zygnematophyceae e Chlorophyceae, respectivamente. As espÃcies raras, a grande maioria, formaram um grupo totalmente isolado daquelas consideradas dominantes, abundantes e pouco abundantes, constituÃdas por um nÃmero reduzido de espÃcies, confirmando a grande influÃncia sazonal da regiÃo, sobre a comunidade fitoplanctÃnica. Os ecossistemas apresentaram grande variaÃÃo na diversidade, riqueza e equitabilidade das espÃcies, no entanto a diversidade foi maior durante a estaÃÃo chuvosa. Com base nos teores de O2 e CO2 dissolvidos, amÃnia total, nitrito, fosfato, bem como, nos Ãndices do estado trÃfico do fosfato e/ou da transparÃncia da Ãgua e na presenÃa de bioindicadores, os estuÃrios dos rios MundaÃ, CauÃpe e CearÃ, a lagoa da Maraponga e os aÃudes Favelas, da Corte e Campus do Itaperi foram classificados como ambientes eutrÃficos; o estuÃrio do Rio Malcozinhado e as lagoas do PecÃm e de Uruaà como mesotrÃficos; e a lagoa de Jijoca e as bicas do Ipu e das AndrÃas como oligotrÃficos. Foram registrados diversos bioindicadores de Ãguas eutrofizadas e/ou poluÃdas, destacando-se a presenÃa de Cyanophyceae potencialmente tÃxicas nos diversos ecossistemas, com blooms no estuÃrio do Rio Cearà e no aÃude Favelas, nÃo sendo registrada uma biomassa significativa nos outros ambientes, mesmo naqueles que apresentaram elevado estado trÃfico, como o aÃude do Campus do Itaperi, com ocorrÃncia de bloom de Chlorophyceae e, no aÃude da Corte, cujo bloom foi de Zygnematophyceae, mostrando que na anÃlise de sanidade dos ecossistemas aquÃticos, a anÃlise conjunta dos parÃmetros biolÃgicos e fÃsico-quÃmicos do ecossistema à de suma importÃncia para um parecer ambiental adequado.Water is the most important resource for humans, though it s eems there is no concern of human beings in preserving it, because daily activities increasingly under mine the quality of this resource. This study aimed to analyze the phytoplankton community structure and water quality in aquatic ecosystems of Cearà State (Brazil). Monthly collections were made during the rainy and dry seasons between 2004 and 2007 in the following ecosystems: the CauÃpe, MundaÃ, Cearà and Malcozinhado river estuarie s; the Jijoca, PecÃm, Uruaà and Maraponga lakes; the Ipu and Andreas waterspouts and the Favelas, Corte and Campus do Itaperi dams. The results showed significant changes in phytoplankton community structure, mainly influenced by levels of rainfall. The Bacillariophyceae were predominant in the ecosystems studied, except in the Favelas, Corte and Campus do Itaperi dams, which showed high levels of eutrophication, with dominance of Cyanophyceae, Zygnematophyceae and Chlorophyceae, respectively. Rare species, the great majorit y, formed a group totally isolated from those considered dominant, abundant and little abundant, consisting of a small number of species, confirming the major seasonal influence of the region's on the phytoplankton community. Ecosystems showed great variation in diversity, richness and evenness of species, however, diversity was highest during the rainy season. The following environments were classified according to the concentration of dissolved O 2 and CO2, total ammonia, nitrite, phosphate, as well as on trophic status indices of phosphate and/or water transparency and on the presence of bioindicators: the MundaÃ, CauÃpe and Cearà river estuaries, Maraponga lake and the Favelas, Corte and Campus do Itaperi dams as eutrophic environments; the Malcozinhado river estuary and PecÃm and Uruaà lakes as mesotrophic environments; and Jijoca lake and the Ipu and AndrÃas waterspouts as oligotrophic environment. Several bioindicators of eutrophic and/or polluted waters were recorded, in partic ular the presence of potentially toxic cyanobacteria in various ecosystems, with blooms in the Cearà river estuary and Favelas dam, while significant biomass was not recorded in other environments, even those showing a high trophic status, such as the Campus do Itaperi dam, with a Chlorophyceae bloom, and the Corte dam, with a Zygnematophyceae bloom, showing that the joint analysis of biological and physicochemical parameters of the ecosystem is of paramount importance for an appropriate environmental assessment of the health of aquatic cosystems.
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Newham, Lachlan Thomas Hopkins, and lachlan newham@anu edu au. "Catchment Scale Modelling of Water Quality and Quantity." The Australian National University. Centre for Resource and Environmental Studies, 2002. http://thesis.anu.edu.au./public/adt-ANU20050919.144548.
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Appropriately constructed pollutant export models can help set management priorities for catchments, identify critical pollutant source areas, and are important tools for developing and evaluating economically viable ways of minimising surface water pollution.¶
This thesis presents a comparison, an evaluation and an integration of models for predicting the export of environmental pollutants, in particular sediment, through river systems. A review of the capabilities and limitations of current water quality modelling approaches is made. Several water quality and quantity modelling approaches are applied and evaluated in the catchment of the upper Murrumbidgee River.¶
The IHACRES rainfall-runoff model and a simple hydrologic routing model are applied with the aim of developing a capacity to predict streamflow at various catchment scales and to enable integration with other pollutant load estimation techniques. Methods for calculating pollutant loads from observed pollutant concentration and modelled streamflow data are also investigated. Sediment export is estimated using these methods over a 10-year period for two case study subcatchments. Approaches for water quality sampling are discussed and a novel monitoring program using rising stage siphon samplers is presented.
Results from a refinement of the Sediment River Network model in the upper Murrumbidgee catchment (SedNet-UM) are presented. The model provides a capacity to quantify sediment source, transport and to simulate the effects of management change in the catchment. The investigation of the model includes rigorous examination of the behaviour of the model through sensitivity assessment and comparison with other sediment modelling studies. The major conclusion reached through sensitivity assessment was that the outputs of the model are most sensitive to perturbation of the hydrologic parameters of the model.¶
The SedNet-UM application demonstrates that it is possible to construct stream pollutant models that assist in prioritising management across catchment scales. It can be concluded that SedNet and similar variants have much potential to address common resource management issues requiring the identification of the source, propagation and fate of environmental pollutants. In addition, incorporating the strengths of a conceptual rainfall-runoff model and the semi-distributed SedNet model has been identified as very useful for the future prediction of environmental pollutant export.
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Liu, Zhijun. "Effective modeling of agricultural practices within large-scale hydrologic and water quality simulations." Diss., Mississippi State : Mississippi State University, 2006. http://library.msstate.edu/etd/show.asp?etd=etd-11082006-162139.
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Hartley, Joanna Katherine. "Parallel algorithms for fuzzy data processing with application to water systems." Thesis, Nottingham Trent University, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.296029.
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Schwartz, Jonathan Aaron. "Compliance with environmental policies in China the role of state capacity /." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/NQ59065.pdf.
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Field, Graeme. "Particle Filters for State Estimation of Confined Aquifers." UNF Digital Commons, 2018. https://digitalcommons.unf.edu/etd/804.
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Mathematical models are used in engineering and the sciences to estimate properties of systems of interest, increasing our understanding of the surrounding world and driving technological innovation. Unfortunately, as the systems of interest grow in complexity, so to do the models necessary to accurately describe them. Analytic solutions for problems with such models are provably intractable, motivating the use of approximate yet still accurate estimation techniques. Particle filtering methods have emerged as a popular tool in the presence of such models, spreading from its origins in signal processing to a diverse set of fields throughout engineering and the sciences including medical research, economics, robotics, and geophysics.
In groundwater hydrology, a key component of aquifer assessment is the determination of the properties which permit water resource managers to estimate aquifer drawdown and safe yield. Presented is a particle filtering approach to estimate aquifer properties from transient data sets, leveraging recently published analytically-derived models for confined aquifers. The approach is examined experimentally through validation against three common aquifer testing problems: determination of (i) transmissivity and storage coefficient from non-leaky confined aquifer performance tests, (ii) transmissivity, storage coefficient, and vertical hydraulic conductivity of a confining unit from leaky confined aquifer performance tests, and (iii) transmissivity and storage coefficient from non-leaky confined aquifer performance tests with noisy data and boundary effects. The first two problems are well-addressed and the presented approach compares favorably to the results obtained from other published methods. The third problem, which the presented method can tackle more naturally than previously-published methods, underscores the flexibility of particle filtering and, in turn, the promise such methods offer for a myriad of other geoscience problems
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Cubas, Suazo Alexa Maria. "Occoquan Reservoir and Watershed: A Water Quality Assessment 1973–2019." Thesis, Virginia Tech, 2021. http://hdl.handle.net/10919/103037.
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The Occoquan Reservoir is part of the largest indirect potable reuse systems in the United States. It in an important water supply source for the Northern Virginia area, as well as, an ecological and recreational area. Furthermore, the Occoquan Reservoir protects the water quality of the Chesapeake Bay because it acts as a trap for sediments and pollutants. Continuous water quality monitoring and evaluation is critical to preserve this important water resource. Reservoir water quality can be affected by the delivery of pollutants from point and nonpoint sources, potentially causing problems such as eutrophication, excess salinization, presence of compounds that affect human and aquatic health. Different management strategies have been implemented at the Occoquan Reservoir to nutrient loading into the reservoir and address eutrophication issues, including nitrate addition to hypolimnetic waters and installation of a hypolimnetic oxygenation system. The goal of this study is to assess how current management strategies implemented in the Occoquan Reservoir have affected the water quality from 1973 to 2019, with particular emphasis on the data since 2003. This analysis of the Occoquan Reservoir and its tributary watershed includes the evaluation of hydrometeorological data and morphometric characteristics; establishment of long-term trends for water quality constituents; and determination of the trophic state of the reservoir. Data from water samples from four different stations located at the Occoquan Reservoir and four stations located throughout the Occoquan tributary watershed were analyzed for nutrients, principal ions and metals, synthetic organic compounds (SOCs), and other water quality parameters. Long-term water quality trends were determined using Mann-Kendall test and relationship between constituents was evaluated using Principal Component Analysis (PCA). Trophic state of the reservoir was assessed using Carlson's Trophic State Index (TSI), Vollenweider Model, and Rast, Jones, and Lee's Model. Results indicate the Occoquan Reservoir is a eutrophic waterbody. However, the nitrate management strategy and the installation of the hypolimnetic system have improved reservoir water quality, reducing concentrations of nutrients and metals.Master of Science
The Occoquan Reservoir is part of the largest indirect potable reuse systems in the United States. Indirect potable reuse refers to the planned discharge of reclaimed water into a water supply source, such as a reservoir or lake. The Occoquan Reservoir also serves as an ecological and recreational area, and serves to protects the water quality of the Chesapeake Bay because it acts as a trap for sediments and pollutants. To protect the different ecosystem services that the reservoir provides, it is critical to continuously monitoring and evaluate its water quality. Reservoir water quality can be affected by the delivery of pollutants from industrial and municipal waste discharges (point sources), as well as, from urban and agricultural runoff (nonpoint sources). Contaminants include nutrients (such as nitrogen and phosphorus), ions, metals, and synthetic organic compounds (SOCs) that can affect human and aquatic health. Different management strategies have been implemented at the Occoquan Reservoir to reduce load of pollutants into the reservoir, particularly to reduce concentrations of nutrients, as excessive nutrients can degrade water quality. Two strategies implemented are the addition of nitrogen, in the form of nitrate, and the installation of an oxygenation system at the reservoir bottom waters. The goal of this study is to assess how current management strategies implemented in the Occoquan Reservoir have affected the water quality from 1973 to 2019, with particular emphasis on the data since 2003. This analysis of the Occoquan Reservoir and its tributary watershed includes the evaluation of the hydrological, meteorological, and morphometric characteristics of the Occoquan Reservoir and Watershed; establishment of long-term trends for water quality constituents; and determination of the productivity (trophic state) of the reservoir. Data from water samples from four different stations located at the reservoir and four stations located throughout the watershed were analyzed for nutrients, principal ions and metals, SOCs, and other water parameters indicative of water quality. Statistical analyses were employed to determine long-term water quality trends (Mann-Kendall test) and relationship between constituents (Principal Component Analysis - PCA). The trophic state of the reservoir was assessed using three methods: Carlson's Trophic State Index (TSI), Vollenweider Model, and Rast, Jones, and Lee's Model. Results indicate the Occoquan Reservoir is eutrophic, or highly enriched with nutrients and productive. However, management strategies employed have improved the water quality and the reservoir continues to improve, though at a slow rate.
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Bontrager, Austin. "Estimation of agricultural soil erosion and surface water quality trends in the Cheney Lake watershed." Thesis, Kansas State University, 2011. http://hdl.handle.net/2097/13182.
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Master of ScienceDepartment of Agronomy
Nathan Nelson
Phosphorus and sediment runoff are the primary cause of eutrophication in Cheney Lake, the primary water source for Wichita, Kansas. Best Management Practices (BMPs) such as no-till farming practices and nutrient management can be implemented to reduce phosphorus runoff on high-risk agricultural fields. Past efforts have established BMP use in this watershed, although the effectiveness of these efforts has not been evaluated. The goals of this project were to identify any existing water quality trends in the Cheney Lake watershed, estimate the current distribution of erosion in the watershed, and evaluate the placement of BMPs with regards to field-scale erosion risk. Parametric, multi-linear regression and non-parametric, seasonal Mann-Kendall analyses were used to identify trends in the Total Suspended Solids (TSS) and Total Phosphorus (TP) of grab samples from the North Fork Ninnescah River. A Geographic Information System (GIS) model based on the Revised Universal Soil Loss Equation (RUSLE) was used to estimate watershed-scale erosion, prioritize agricultural land for BMP placement, and evaluate existing placement of BMPs within the Cheney Lake watershed. No detectible trends were identified in the water quality data due to stream variability, frequency of sampling, or absence of actual improvement in water quality. Additional sampling must be done to detect any trends in the future. BMPs were implemented on 13% of prioritized field area, and 11% of non-prioritized field area. Conservation Reserve Program (CRP) fields were placed on 14% of prioritized field area, and 5% of non-prioritized field area. No-till practices were implemented on 13% of prioritized field area, and 18% of non-prioritized field area. The top 20% eroding fields were identified given current conditions, and account for approximately 56% of the watershed-wide erosion. The GIS method has demonstrated utility in evaluating past erosion control measures for the watershed and in informing future decisions concerning BMP placement.
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Wang, Ye. "Advances in state estimation, diagnosis and control of complex systems." Doctoral thesis, Universitat Politècnica de Catalunya, 2018. http://hdl.handle.net/10803/669680.
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This dissertation intends to provide theoretical and practical contributions on estimation, diagnosis and control of complex systems, especially in the mathematical form of descriptor systems. The research is motivated by real applications, such as water networks and power systems, which require a control system to provide a proper management able to take into account their specific features and operating limits in presence of uncertainties related to their operation and failures from component malfunctions. Such a control system is expected to provide an optimal operation to obtain efficient and reliable performance.
State estimation is an essential tool, which can be used not only for fault diagnosis but also for the controller design. To achieve a satisfactory robust performance, set theory is chosen to build a general framework for descriptor systems subject to uncertainties. Under certain assumptions, these uncertainties are propagated and bounded by deterministic sets that can be explicitly characterized at each iteration step. Moreover, set-invariance characterizations for descriptor systems are also of interest to describe the steady performance, which can also be used for active mode detection.
For the controller design for complex systems, new developments of economic model predictive control (EMPC) are studied taking into account the case of underlying periodic behaviors. The EMPC controller is designed to be recursively feasible even with sudden changes in the economic cost function and the closed-loop convergence is guaranteed. Besides, a robust technique is plugged into the EMPC controller design to maintain these closed-loop properties in presence of uncertainties.
Engineering applications modeled as descriptor systems are presented to illustrate these control strategies. From the real applications, some additional difficulties are solved, such as using a two-layer control strategy to avoid binary variables in real-time optimizations and using nonlinear constraint relaxation to deal with nonlinear algebraic equations in the descriptor model. Furthermore, the fault-tolerant capability is also included in the controller design for descriptor systems by means of the designed virtual actuator and virtual sensor together with an observer-based delayed controller.Esta tesis propone contribuciones de carácter teórico y aplicado para la estimación del estado, el diagnóstico y el control óptimo de sistemas dinámicos complejos en particular, para los sistemas descriptores, incluyendo la capacidad de tolerancia a fallos. La motivación de la tesis proviene de aplicaciones reales, como redes de agua y sistemas de energía, cuya naturaleza crítica requiere necesariamente un sistema de control para una gestión capaz de tener en cuenta sus características específicas y límites operativos en presencia de incertidumbres relacionadas con su funcionamiento, así como fallos de funcionamiento de los componentes. El objetivo es conseguir controladores que mejoren tanto la eficiencia como la fiabilidad de dichos sistemas. La estimación del estado es una herramienta esencial que puede usarse no solo para el diagnóstico de fallos sino también para el diseño del control. Con este fin, se ha decidido utilizar metodologías intervalares, o basadas en conjuntos, para construir un marco general para los sistemas de descriptores sujetos a incertidumbres desconocidas pero acotadas. Estas incertidumbres se propagan y delimitan mediante conjuntos que se pueden caracterizar explícitamente en cada instante. Por otra parte, también se proponen caracterizaciones basadas en conjuntos invariantes para sistemas de descriptores que permiten describir comportamientos estacionarios y resultan útiles para la detección de modos activos. Se estudian también nuevos desarrollos del control predictivo económico basado en modelos (EMPC) para tener en cuenta posibles comportamientos periódicos en la variación de parámetros o en las perturbaciones que afectan a estos sistemas. Además, se demuestra que el control EMPC propuesto garantiza la factibilidad recursiva, incluso frente a cambios repentinos en la función de coste económico y se garantiza la convergencia en lazo cerrado. Por otra parte, se utilizan técnicas de control robusto pata garantizar que las estrategias de control predictivo económico mantengan las prestaciones en lazo cerrado, incluso en presencia de incertidumbre. Los desarrollos de la tesis se ilustran con casos de estudio realistas. Para algunas de aplicaciones reales, se resuelven dificultades adicionales, como el uso de una estrategia de control de dos niveles para evitar incluir variables binarias en la optimización y el uso de la relajación de restricciones no lineales para tratar las ecuaciones algebraicas no lineales en el modelo descriptor en las redes de agua. Finalmente, se incluye también una contribución al diseño de estrategias de control con tolerancia a fallos para sistemas descriptores.
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Bernos, Lisa. "An examination of the new Federal and State storm water regulations : an electric utility perspective." Thesis, Georgia Institute of Technology, 1996. http://hdl.handle.net/1853/29557.
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Whitaker, David Kevin. "One-Dimensional Computer Modeling of Thermal and Water Quality Characteristics of Coldwater Lake, WA." PDXScholar, 1993. https://pdxscholar.library.pdx.edu/open_access_etds/4676.
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Coldwater Lake is a new lake formed when a massive mudflow down the Toutle River Valley, caused by the eruption of Mount St. Helens on May 18, 1980, blocked the natural outlet of Coldwater Creek. This research utilizes physical, biological and chemical data collected at Coldwater Lake during the sun1mers of 1989 and 1990 to calibrate and verify the one-dimensional computer models CE-THERMRl and CE-QUAL-Rl for Coldwater Lake. CE-THERM-R1 was used to simulate thermal characteristics in Coldwater Lake during the summer stratification periods of 1989 and 1990. The model was calibrated to 1989 data and was verified with 1990 data. The model performed well with respect to typical stratification features such as depth and temperature of the epilimnion, gradient of the thermocline and temperature of the hypolimnion. The 1990 verification simulation indicated a lack of heat in the epilimnion and metalimnion towards the end of the summer. This is thought to be a product of inaccurate cloud cover data. Model simulations predicted vertical eddy diffusion coefficients (Ez) throughout the water column. These were compared to Ez values in the hypolimnion calculated from temperature data collected by Kelly (1991). Model simulated Ez values in the hypolimnion were near molecular diffusion while field calculated values were one to two orders of magnitude greater than molecular diffusion. The model simulation assumed no lake inflow or outflow so the hypolimnion was more stable than the natural system. The amount of photosynthetically available radiation (PAR) to Coldwater Lake was determined from output derived from the model simulation. This will be useful in determining primary productivity within the lake. CE-QUAL-R1 was used to simulate water quality in Coldwater Lake. The model was calibrated using dissolved oxygen (D.O.) data collected in 1989. The model adequately predicted the D.O. profile in the hypolimnion but tended to over predict D.O. concentration in the epilimnion by 1.0- 3.0 mg/1. This may be caused by an under estimation of the vertical diffusion coefficient in the model simulation. Mean phytoplankton concentrations were similar to field data in the surface layer assuming a 1 mg/1 phytoplankton to 10 ug/1 chlorophyll a ratio. However, concentrations at 10 m and 20 m were under predicted. The phytoplankton - chlorophyll a comparison may not be valid for these lower regions because a significant portion of algal cells within this region are non-viable and are found as particulate detritus in various stages of decomposition. Model simulated nutrient concentrations were in good agreement with the field data. N03 concentration in the hypolimnion increased slightly throughout the model simulation due to decay of the assumed initial condition of 2 mg/1 refractory dissolved organic matter which was contributed to the lake during the eruption of Mt. Saint Helens on May 18, 1980. The model simulation predicted that the phytoplankton were nitrogen limited. An analysis of potential changes in water clarity and water temperature due to the addition of fish in the summer of 1989 was made. The 1990 model simulation predicted that the addition of 200 kg/hectare of Rainbow Trout had little change on water temperature and water clarity. Collection of further site specific data such as; cloud cover estimates, primary productivity rates and quantity of dissolved organic matter contributed by the May 18, 1980 eruption of Mt. Saint Helens would be useful in building a reliable water quality model at Coldwater Lake.
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Hamiter, Bonnie Leigh. "WATERSHED-SCALE SEDIMENT MOVEMENT IN RELATION TO IN-STREAM WATER QUALITY: PRE- AND POST-HARVEST OBSERVATIONS." MSSTATE, 2009. http://sun.library.msstate.edu/ETD-db/theses/available/etd-03242009-161241/.
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Sediment is a leading contributor to nonpoint source (NPS) pollution in streams and rivers. Sources and sinks of sediment movement were identified for a 121-hectare watershed located in Webster County, Mississippi in order to evaluate the impact of forest harvesting on water quality and sedimentation rates. In a completely randomized design containing three replications of two treatments (unharvested vs. harvested) and two slopes (≤9% vs. >9%), twelve sub-watersheds were randomly selected for intensive measurement of the sources and sinks of sediment after precipitation events. In-stream, bank and forest road sediment movement were also monitored pre- and post-harvest. Total suspended sediment (TSS) in runoff from forest roads ranged from 36-188 g/L with a consistent trend of decreasing sediment concentrations with increasing distance from the road. Within the watershed, erosional processes dominated however there was little net change in soil elevation one year post-harvest.
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Costa, Maria Tereza Pinto da. "Study on the quality of the salt-added water produced on the State of CearÃ." Universidade Federal do CearÃ, 2013. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=11268.
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To the Resolution from the Board of Directions â RDC No 274/05, from the National Agency of Sanitary Vigilance (ANVISA), that approves the âTechnical Regulation for Bottled Water and Iceâ, the salt-added water is a bottled water that is prepared and bottled containing one or more salts, without any addition of sugars, sweeteners, flavors or other ingredients, destined for human consumption. This resolution does not specify the characteristics for identity fixing or the quality of the bottled salt-added water, and has as only requirement that the water used for its prepare is in accord with the microbiological, chemical and radioactive parameters of the âQuality of the Water for Human Consumption Normâ. However, the current Directive No. 2.914/11 from the Ministry of Health does not apply to the salt-added water after its bottling, nor to the water used as raw material for the product. Willing to evaluate the quality of the salt-added water in its two stages of manufacture, (well water, used as raw material and the bottled water, in 20-liter carboys) from salt-added water producer industries from the State of CearÃ, samples were collected in 15 companies, in three distinct periods of time, totalling 270 samples. The microbiological analysis performed were: Determination of Total coliforms and Escherichia coli (Chromogenic substrate technique); Enterococcus, Pseudomonas aeruginosa, Clostridium perfringens (Filtering membrane technique); Heterotrophic bacteria (Culture in Depth technique), and phisico-chemical analysis; Determination of Nitrate, Nitrite (Spectrophotometric method); Residual Chlorine and pH (Electroanalytical measuringIt was verified that the well water used as raw material in 11 (73, 33%) of the 15 companies does not fill the standards of the water potability for human consumption. Regarding the bottled water, it was verified that in 14(93, 33%) of the companies, it does not follow the phisico-chemical and microbiological parameters for mineral water and for water for human consumption. It was concluded that an update in the sanitary legislation of the salt-added water product is necessary and urgent in order to prevent damages on the Health of the consumer population.Para a ResoluÃÃo da Diretoria Colegiada - RDC N 274/05 da AgÃncia Nacional de VigilÃncia SanitÃria (ANVISA) que aprova o "Regulamento TÃcnico para Ãguas Envasadas e Gelo", a Ãgua adicionada de sais à a Ãgua para consumo humano, preparada e envasada, contendo um ou mais sais, sem adiÃÃo de aÃucares, adoÃantes, aromas ou outros ingredientes. Esta ResoluÃÃo nÃo especifica as caracterÃsticas para fixaÃÃo da identidade e qualidade da Ãgua adicionada de sais envasada, e tem como requisito especÃfico, que a Ãgua utilizada para preparo desse produto atenda aos parÃmetros microbiolÃgicos, quÃmicos e radioativos da Norma de Qualidade da Ãgua para Consumo Humano. Entretanto, a atual Portaria N 2.914/11 do MinistÃrio da SaÃde, nÃo se aplica a Ãgua adicionada de sais apÃs o envasamento, e a outras Ãguas utilizadas como matÃria-prima para elaboraÃÃo de produto. Com o objetivo de avaliar a qualidade da Ãgua em duas etapas de produÃÃo Ãgua bruta (poÃo) utilizada como matÃria-prima e Ãgua envasada (garrafÃes de 20 litros), obtida de indÃstrias produtoras de Ãguas Adicionadas de Sais no Estado do CearÃ, foram coletadas amostras, em quinze empresas e em trÃs perÃodos distintos, totalizando 270 amostras. As anÃlises microbiolÃgicas realizadas foram: determinaÃÃo de coliformes totais e Escherichia coli (tÃcnica de substratos cromogÃnicos); Enterococcus, Pseudomonas aeruginosa, Clostridium perfringens (tÃcnica de membrana filtrante); bactÃrias heterotrÃficas (tÃcnica de cultivo em profundidade) e as anÃlises fÃsico-quÃmicas: determinaÃÃo de nitrato, nitrito (mÃtodo espectrofotomÃtrico); cloro residual e pH (medidas eletroanalÃticas). Verificou-se que a Ãgua bruta utilizada como matÃria-prima em onze (73,33%), das quinze empresas, nÃo atende aos padrÃes de potabilidade da Ãgua para consumo humano. Com relaÃÃo à Ãgua envasada constatou-se que quatorze (93,33%) empresas, nÃo atende aos parÃmetros microbiolÃgicos e fÃsico-quÃmicos para Ãgua mineral natural e Ãgua para consumo humano. Concluiu-se que se faz necessÃria e urgente a atualizaÃÃo da legislaÃÃo sanitÃria do produto Ãgua adicionada de sais envasada, visando à prevenÃÃo de danos a saÃde da populaÃÃo consumidora.
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Langley, Kenneth Tyler. "The effect of policy and land use change on water quality in a coastal watershed city an analysis of Covington, Louisiana /." Master's thesis, Mississippi State : Mississippi State University, 2008. http://library.msstate.edu/etd/show.asp?etd=etd-08092008-150443.
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McCulloch, Andrew John. "Developing and Calibrating the Hydrodynamic and Water Quality Model CE-QUAL-W2 for Banks Lake Washington." PDXScholar, 2011. https://pdxscholar.library.pdx.edu/open_access_etds/180.
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Located in central Washington State, Banks Lake serves as an irrigation storage reservoir for the Columbia Basin Irrigation Project and is home to a diverse fisheries population. The current hydrologic management strategies used for Banks Lake have been chosen to serve two purposes: to adequately store and provide irrigation water for the Columbia Basin Irrigation Project and to maintain a healthy aquatic environment suitable for the growth and habitation of local flora and fauna. Increased needs for irrigation water within arid central Washington poses additional challenges to reservoir managers so that irrigation needs are met without damaging the present aquatic environment within Banks Lake. Future plans by the Washington Department of Ecology to use Banks Lake storage to replenish ground water reserves of the Odessa Subarea aquifer have required an investigation into how increased seasonal drawdown may affect fish growth, fish habitat and overall limnology of Banks Lake. The goal of this project is to produce a hydrodynamic and water quality model of Banks Lake that can predict the impacts of management strategies on the lake's water quality and the linkage of lake management to fish habitat.
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Van, Glubt Sarah. "Hydrodynamic and Water Quality Modeling of the Chehalis River Using CE-QUAL-W2." PDXScholar, 2017. https://pdxscholar.library.pdx.edu/open_access_etds/3486.
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The Chehalis River Basin is located in the southwest region of Washington State, originating in the Olympic Mountains and flowing to Grays Harbor and the Pacific Ocean. The Chehalis River is over 125 miles, exists within five counties, and flows through agricultural, residential, industrial, and forest land areas. Four major rivers discharge to the Chehalis River, as well as many smaller creeks, five wastewater treatment plants, and groundwater flows.
Flooding is a major problem in the relatively flat areas surrounding the cities of Chehalis and Centralia, with severe consequences for property, safety and transportation. As a result, construction of a flood-control dam in the upper basin has been proposed. One major concern of constructing a dam is the potentially severe impacts to fish health and habitat. The Chehalis River has routinely violated water quality standards for primarily temperature and dissolved oxygen, and has had multiple water quality and Total Maximum Daily Load studies beginning in 1990.
CE-QUAL-W2, a two-dimensional (longitudinal and vertical) hydrodynamic and water quality model, was used to simulate the Chehalis River, including free flowing river stretches and stratified (in summer) lake-like stretches. The goals of this research were to assess the flood retention structure's impacts to water quality, as well as river responses to potential climate change scenarios.
In order to use the model to achieve these goals, calibration to field data for flow, temperature, and water quality constituents was performed. This involved developing meteorological data, riparian shading data, and flow, temperature, water quality records for all tributaries during the calibration period of January 1, 2013 to December 31, 2014. System cross-sectional geometry data were also required for the model grid. Because of the short travel time in the river, the model was sensitive to boundary condition data, wind speed, bathymetry, nutrient kinetics, and algae, epiphyton, and zooplankton kinetics.
Future conditions showed predictions of warmer water temperatures and slight changes to water quality conditions on the river. As fish in the area prefer cooler water temperatures, this could pose a threat to fish health and habitat. Flood retention structures also showed impacts to river temperature and water quality. Structures with the purpose of flood retention only (only operating during times of flooding) gave model predictions for daily maximum temperature higher than structures that employed flood retention and flow augmentation (operating during all times of the year). This suggested the management of flow passage or retention by the dam is important for water quality on the river.
As this research continues improvements will be made, particularly to temperature and water quality constituents. Additional data for the system would be beneficial to this process. Model predictions of temperature were sensitive to meteorological data, including cloud cover, which were largely estimated based on solar radiation. Additional meteorological data throughout the basin would be useful to temperature results. Temperature results were also sensitive to the model bathymetry, and additional investigations into segments widths and water depths may improve temperature predictions.
Water quality constituent data were largely lacking for the system. Many estimation techniques and approximations were used for input water quality constituents for the model upstream boundary and tributaries when little or no data were available, introducing uncertainty to the model. It was not possible to calibrate pH to field data because alkalinity data were essentially unavailable. However, other constituents had good agreement between model predictions and field data, including dissolved oxygen, nitrates, total phosphorus, and total suspended solids.
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Tagert, Mary Love Mortimer. "Water quality, modeling, and land use investigations in the Upper Pearl River Basin of east-central Mississippi." Diss., Mississippi State : Mississippi State University, 2006. http://sun.library.msstate.edu/ETD-db/ETD-browse/browse.
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Parandekar, Amey V. "Development of a decision support framework for integrated watershed water quality management and a Generic Genetic Algorithm Based Optimizer." Raleigh, NC : North Carolina State University, 1999. http://www.lib.ncsu.edu/etd/public/etd-492632279902331/etd.pdf.
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Nemeth, Douglas J. "Relationship of Aeromonas hydrophila to fish community health and water quality parameters." Virtual Press, 1985. http://liblink.bsu.edu/uhtbin/catkey/421946.
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Temperature, conductivity, and Aeromonas hydrophila density were determined bimonthly at six sites in the White River drainage system, Delaware County, Indiana, from April, 1984 through December, 1984. Fish were collected from four of the six sites. Fish were identified to species, examined for gross pathology, and their blood collected. Titers against A. hydrophila antigen 157 were determined for all carp (Cyprinus carpio) captured. Certain carp serum samples were also tested against three additional A. hydrophila antigens.Aerononas hydrophila densities appeared to be related to temperature and conductivity, primary producers, and runoff/effluent. Aeromonas hydrophila densities were higher in areas affected by urban runoff/ effluent than in areas affected by rural runoff/effluent. Aeromonas hydrophila densities increased as one progressed through the city of Muncie.Only five percent of all fish captured exhibited signs of gross pathology. Diseased fish typically demonstrated low titers against antigen 157. Several A. hydrophila serotypes were apparently infectious for the carp studied. Thirty-two percent of the carp sampled exhibited a positive titer response against antigen 157. Considerable variation in titer response existed between individuals.Ball State UniversityMuncie, IN 47306
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Xu, Wenwei. "Development of a Steady-State River Hydrodynamic and Temperature Model Based on CE-QUAL-W2." PDXScholar, 2014. https://pdxscholar.library.pdx.edu/open_access_etds/1619.
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CE-QUAL-W2 is a 2-D hydrodynamic and water quality model that has been applied to reservoirs, lakes, river systems, and estuaries throughout the world. However, when this model is applied for shallow systems, this model requires a long calculation time to maintain numerical stability, compared to applications of reservoirs or deeper river systems.
To solve this problem, a new hydrodynamic and temperature model was built based on the framework of CE-QUAL-W2 but that allows for steady-state hydrodynamic computations. By calculating the hydrodynamics at steady-state, the time step for stability is relaxed and simulations can proceed at much higher time steps. The rest of the model framework is still used for water quality state variables, in this case, temperature. The algorithm used for computing the water surface elevation is Manning's equation.
This thesis study is one part of the Willamette Water 2100 project (Santelmann et al., 2012), which examines hydrological, ecological, and human factors affecting water scarcity in the Willamette River Basin. This study included three stages: (1) Convert six existing CE-QUAL-W2 V3.1 models into a newer version: CE-QUAL-W2 V3.7. (2) Develop the steady-state model code in FORTRAN. (3) Test the steady-state model on three river systems in the Willamette River Basin at Year 2001 and 2002.
The result proved that the steady-state model could reduce the computing time by 90% for river applications, while predicting dynamic river temperature with high accuracy at a two-minute time scale. This new model will be employed to simulate the future of the Willamette River System at a decadal or centennial timescales, addressing river temperature concerns and fish habitat issues.
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Wells, Vanessa I. "CE-QUAL-W2 Water Quality and Fish-bioenergetics Model of Chester Morse Lake and the Cedar River." PDXScholar, 2011. https://pdxscholar.library.pdx.edu/open_access_etds/324.
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Many communities are currently seeking to balance urban water needs with preservation of sensitive fish habitat. As part of that effort, CE-QUAL-W2, a hydrodynamic and temperature model, was developed for Chester Morse Lake and the lower Cedar River, WA. Chester Morse Lake is approximately 10 km long with a maximum depth at full pool of 40 m. The Cedar River model started immediately downstream of the Chester Morse dam and ended 21 km downstream at Landsburg, where drinking water is diverted for the City of Seattle. This water quality model was coupled with a fish habitat and bioenergetics model for bull trout and was calibrated to temperature data between 2005 and 2008. Bull trout fish bioenergetics parameters were provided by the USGS. The CE-QUAL-W2 model was found to be highly accurate in modeling temperature variation in the lake - at most locations having an average absolute mean error of between 0.5 and 0.8 oC. The Cedar River model had an average absolute mean error of 0.7oC. This tool is designed to allow managers and operators to estimate the impact to fish habitat and growth potential from various management decisions including extent of drawdown, timing/volume of flows, and various pumping operations. Future studies could include incorporating further water quality parameters such as nutrients, algae, and zooplankton as they relate to fish productivity.
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Essic, Jefferson Forrest. "Applications of geographic information systems for growth management planning and water quality protection in the coastal region of North Carolina." Raleigh, NC : North Carolina State University, 1997. http://www.lib.ncsu.edu/etd/public/etd-2732139098580/ETD.PDF.
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Turano, Marc John. "The effects of cyclic feeding on compensatory growth and water quality in hybrid striped bass, Morone chrysops x M. saxitilis." NCSU, 2006. http://www.lib.ncsu.edu/theses/available/etd-03222006-150555/.
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A series of pond and tanks studies were conducted to determine if compensatory growth (CG) could be elicited in hybrid striped bass (HSB; Morone chrysops x M. saxitilis) through manipulations in feeding that involve sequential cycles of feed deprivation followed by daily satiation feeding. Growth, feed efficiency (FE), hepatosomatic index (HSI), intraperitoneal fat ratio (IPF), and condition factor (CF) were assessed at intervals throughout the growth trials to characterize the nutritional status (catabolic state) and CG response of HSB. Measurements of pituitary growth hormone (GH) cell activity (gene expression, protein stores), and plasma GH were assessed in tank studies to identify the potential catabolic and anabolic role of this growth promoting hormone during feed deprivation and CG. Lastly, the effects of the cyclic feeding regimes on water quality were assessed in ponds trials. In each of the three studies, growth compensation, defined by growth rates that exceed that of control fish fed daily, was observed when treatment fish were realimentated to a control daily satiation feeding following a period of feed deprivation. Cyclic feeding increased overall FE of treatment fish over the controls by 10.8-40.0 % in the first pond study (HSB fingerlings), and 7.0-8.5% in the second pond study (HSB food fish) but not in the tank study. Hepatasomatic index and CF varied significantly with feed deprivation and refeeding, and were useful predictors of the CG response following feed deprivation. There was an inverse relationship between all GH measurements and nutritional status, with no reported compensatory changes in GH. Changes in water quality parameters due to cyclic feeding were only observed in the pond study with HSB food fish. Ponds subjected to the cyclic feeding regimes had 25-38 % lower levels of total phosphorus, 23.9-41.3 % less soluble reactive phosphorus, and 11.6-27.8% less chlorophyll-a. Based on these results, CG can be repeatedly induced in HSB in both ponds and tanks, albeit full growth compensation was not achieved under the cyclic feeding conditions used in these studies. Regardless, these studies suggest that cyclic feeding can improve overall FE and water quality in pond-raised HSB. Further studies are required to ascertain the optimal catabolic conditions needed to induce full growth compensation during HSB production.
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Metheny, Maura Agnew. "Evaluation of groundwater flow and contaminant transport at the Wells G&H Superfund Site, Woburn, Massachusetts, from 1960 to 1986 and estimation of TCE and PCE concentrations delivered to Woburn residences." Connect to this title online, 2004. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1080248307.
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Thesis (Ph. D.)--Ohio State University, 2004.Title from first page of PDF file. Document formatted into pages; contains xx, 346 p.; also includes maps, graphics (some col.) Includes bibliographical references (p. 315-325). Available online via OhioLINK's ETD Center
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Barros, Lilian Rodolfo. "The Trophic state index and its adaptation to the lentics systems present in Cearà semiarid." Universidade Federal do CearÃ, 2013. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=11376.
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Para suprir a carÃncia hÃdrica, o Cearà dispÃe de uma grande rede de reservatÃrios artificiais destinados aos mais diversos usos. PorÃm, Ãguas que permanecem reservadas em aÃudes sÃo limnolÃgicamente vulnerÃveis, sendo o fenÃmeno da eutrofizaÃÃo uma das piores consequÃncias resultantes das atividades antrÃpicas desenvolvidas nas Ãreas de contribuiÃÃo desses reservatÃrios, consequÃncias essas que sÃo agravadas ainda mais em funÃÃo das caracterÃsticas naturais do semiÃrido, um ambiente marcado por baixas precipitaÃÃes pluviomÃtricas e pela
sua mà distribuiÃÃo no espaÃo e no tempo. Para auxiliar no estudo trÃfico dessas Ãguas, hà muito vem sendo utilizada pelos limnÃlogos uma ferramenta destinada a classificar os recursos hÃdricos no tocante ao seu estado de trofia, o IET - Ãndice do
Estado TrÃfico, desenvolvido por Carlson (1977).
A pesquisa aqui desenvolvida consistiu em aprimorar o estudo da correlaÃÃo entre os parÃmetros de Clorofila a, fÃsforo total e TransparÃncia de Secchi, utilizados na composiÃÃo do IET, bem como ajustar a escala logaritmica do Ãndice, basaeando-se
nas medidas mÃnimas e mÃximas de Secchi para os reservatÃrios de Ãgua do CearÃ, o que resultou em uma metodologia de classificaÃÃo trÃfica adaptada Ãs condiÃÃes dos sistemas lÃnticos inseridos no semiÃrido cearense.To meet the water shortage, Cearà has an extensive network of artificial reservoirs intended for various uses. However, waters that remain reserved in dams present limnological vulnerability, and the phenomenon of eutrophication is one of the worst consequences of anthropic activities developed in the areas of contribution of these reservoirs, consequences that are aggravated due to the natural characteristics of semiarid, an environment marked by low rainfall and its poor distribution in space and time. To assist the trophic study of these waters, it has long been used by limnologists a tool to classify water resources in relation to their trophic state, the TSI - the Trophic State Index, developed by Carlson (1977). The research conducted here was to enhance the study of the correlation among the parameters of chlorophyll a, total phosphorus, and Secchi Transparency, used in the composition of the TSI, as well as to adjust the logarithmic scale of the index, according to Secchi's maximum and mi nimum measures to the water reservoirs of CearÃ, which resulted in a trophic classification methodology adapted to the conditions of the inserted lentic systems in Cearà semiarid
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Frye, Rich. "Determining the Trophic State of Sweet Briar Lake and the Influence Water Quality has on the Aquatic Life." Thesis, Minot State University, 2017. http://pqdtopen.proquest.com/#viewpdf?dispub=10617386.
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In this study, the water quality of Sweet Briar Lake was tested to determine the trophic state of the lake and to determine if the lake can support aquatic organisms. Water samples were collected from two locations at different depths. Samples were collected once a month for six months. Six tests were conducted to help determine the trophic state and water quality of the lake. The tests conducted were nitrogen concentration, phosphorus concentration, Chlorophyll-a concentration, Secchi disc transparency, dissolved oxygen levels and water temperature. Total nitrogen at both locations ranged from 1.767 mg/L to 3.340 mg/L. Total phosphorus at both locations ranged from 0.086 mg/L to 0.724 mg/L. Chlorophyll-a concentrations at location 1 ranged from 0.0176 mg/L to 0.0412 mg/L and location 2 ranged from 0.00834 mg/L to 0.0147 mg/L. Secchi disc transparency at location 1 ranged from 0.4 m to 0.6 m and location 2 ranged 0.6 m to 1.75 m. Oxygen levels did not fall below 2 mg/L except at location 2, during the months of June and July. All tests indicated that Sweet Briar Lake was highly eutrophic to hypereutrophic. Oxygen levels in the lake are adequate to support aquatic organisms.
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Leitch, Katherine McArthur. "Estimating Tributary Phosphorus Loads Using Flow-Weighted Composite Storm Sampling." Thesis, Virginia Tech, 1998. http://hdl.handle.net/10919/10078.
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Quantification of total phosphorus (TP) loads entering a lake or reservoir is important because phosphorus is most often the limiting nutrient in terms of algae growth, thus phosphorus can control the extent of eutrophication. Four methods for assessing the annual tributary phosphorus loads to two different Virginia reservoirs were analyzed, three methods that use tributary monitoring program data and one that uses land-use and rainfall data. In this project, one tributary has been extensively monitored for many years and served as a control on which the other methods were tested. The key difference between this research and previous studies is the inclusion of flow-weighted composite storm sampling instead of simple grab sample analyses of storm flow. Three of the methods employed flow stratification, and the impact of the base flow separation point was examined. It was found that the Regression Method developed in this research was the least sensitive to the base flow separation point, which is a valuable attribute because a wrong choice will not significantly affect the estimate. The Monte Carlo Method was found to underestimate the TP loads. The amount of rainfall impacted the accuracy of the methods, with more error occurring in a year with lower precipitation.Master of Science
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Gilfillan, Dennis, Timothy Andrew Joyner, and Phillip R. Scheuerman. "Maxent Estimation of Aquatic Escherichia Coli Stream Impairment." Digital Commons @ East Tennessee State University, 2018. https://dc.etsu.edu/etsu-works/5480.
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Background: The leading cause of surface water impairment in United States’ rivers and streams is pathogen contamination. Although use of fecal indicators has reduced human health risk, current approaches to identify and reduce exposure can be improved. One important knowledge gap within exposure assessment is characterization of complex fate and transport processes of fecal pollution. Novel modeling processes can inform watershed decision-making to improve exposure assessment.
Methods: We used the ecological model, Maxent, and the fecal indicator bacterium Escherichia coli to identify environmental factors associated with surface water impairment. Samples were collected August, November, February, and May for 8 years on Sinking Creek in Northeast Tennessee and analyzed for 10 water quality parameters and E. coli concentrations. Univariate and multivariate models estimated probability of impairment given the water quality parameters. Model performance was assessed using area under the receiving operating characteristic (AUC) and prediction accuracy, defined as the model’s ability to predict both true positives (impairment) and true negatives (compliance). Univariate models generated action values, or environmental thresholds, to indicate potential E. coli impairment based on a single parameter. Multivariate models predicted probability of impairment given a suite of environmental variables, and jack-knife sensitivity analysis removed unresponsive variables to elicit a set of the most responsive parameters.
Results: Water temperature univariate models performed best as indicated by AUC, but alkalinity models were the most accurate at correctly classifying impairment. Sensitivity analysis revealed that models were most sensitive to removal of specific conductance. Other sensitive variables included water temperature, dissolved oxygen, discharge, and NO3. The removal of dissolved oxygen improved model performance based on testing AUC, justifying development of two optimized multivariate models; a 5-variable model including all sensitive parameters, and a 4-variable model that excluded dissolved oxygen.
Discussion: Results suggest that E. coli impairment in Sinking Creek is influenced by seasonality and agricultural run-off, stressing the need for multi-month sampling along a stream continuum. Although discharge was not predictive of E. coli impairment alone, its interactive effect stresses the importance of both flow dependent and independent processes associated with E. coli impairment. This research also highlights the interactions between nutrient and fecal pollution, a key consideration for watersheds with multiple synergistic impairments. Although one indicator cannot mimic the plethora of existing pathogens in water, incorporating modeling can fine tune an indicator’s utility, providing information concerning fate, transport, and source of fecal pollution while prioritizing resources and increasing confidence in decision making. Methods
We used the ecological model, Maxent, and the fecal indicator bacterium Escherichia coli to identify environmental factors associated with surface water impairment. Samples were collected August, November, February, and May for 8 years on Sinking Creek in Northeast Tennessee and analyzed for 10 water quality parameters and E. coli concentrations. Univariate and multivariate models estimated probability of impairment given the water quality parameters. Model performance was assessed using area under the receiving operating characteristic (AUC) and prediction accuracy, defined as the model’s ability to predict both true positives (impairment) and true negatives (compliance). Univariate models generated action values, or environmental thresholds, to indicate potential E. coli impairment based on a single parameter. Multivariate models predicted probability of impairment given a suite of environmental variables, and jack-knife sensitivity analysis removed unresponsive variables to elicit a set of the most responsive parameters. Results
Water temperature univariate models performed best as indicated by AUC, but alkalinity models were the most accurate at correctly classifying impairment. Sensitivity analysis revealed that models were most sensitive to removal of specific conductance. Other sensitive variables included water temperature, dissolved oxygen, discharge, and NO3. The removal of dissolved oxygen improved model performance based on testing AUC, justifying development of two optimized multivariate models; a 5-variable model including all sensitive parameters, and a 4-variable model that excluded dissolved oxygen. Discussion
Results suggest that E. coli impairment in Sinking Creek is influenced by seasonality and agricultural run-off, stressing the need for multi-month sampling along a stream continuum. Although discharge was not predictive of E. coli impairment alone, its interactive effect stresses the importance of both flow dependent and independent processes associated with E. coli impairment. This research also highlights the interactions between nutrient and fecal pollution, a key consideration for watersheds with multiple synergistic impairments. Although one indicator cannot mimic theplethora of existing pathogens in water, incorporating modeling can fine tune an indicator’s utility, providing information concerning fate, transport, and source of fecal pollution while prioritizing resources and increasing confidence in decision making.
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Ly, Duy Khiem. "Water quality-based real time control of combined sewer systems." Thesis, Lyon, 2019. http://www.theses.fr/2019LYSEI032/document.
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La gestion en temps réel (GTR) est considérée comme une solution économiquement efficace pour réduire les déversements par temps de pluie car elle optimise la capacité disponible des réseaux d'assainissement. La GTR permet d'éviter la construction de volumes de rétention supplémentaires, d'augmenter l'adaptabilité du réseau aux changements de politiques de gestion de l'eau et surtout d'atténuer l'impact environnemental des déversoirs d'orage. À la suite de l'intérêt croissant pour la GTR fondée sur la qualité de l'eau (QBR), cette thèse démontre une stratégie simple et efficace pour les charges polluantes déversées par temps de pluie. La performance de la stratégie QBR, basée sur la prédiction des courbes masse-volume (MV), est évaluée par comparaison avec une stratégie typique de GTR à base hydraulique (HBR). Une étude de validation de principe est d'abord réalisée sur un petit bassin versant de 205 ha pour tester le nouveau concept de QBR en utilisant 31 événements pluvieux sur une période de deux ans. Par rapport à HBR, QBR offre une réduction des charges déversées pour plus d'un tiers des événements, avec des réductions de 3 à 43 %. La stratégie QBR est ensuite mise en oeuvre sur le bassin versant de Louis Fargue (7700 ha) à Bordeaux, France et comparée à nouveau à la stratégie HBR. En implémentant QBR sur 19 événements pluvieux sur 15 mois, ses performances sont constantes et apportent des avantages précieux par rapport à HBR, 17 des 19 événements ayant une réduction de charge variant entre 6 et 28.8 %. La thèse évalue en outre l'impact de l'incertitude de prédiction de la courbe MV (due à l'incertitude de prédiction du modèle) sur la performance de la stratégie QBR, en utilisant un événement pluvieux représentatif. La marge d'incertitude qui en résulte est faible. En outre, l'étude de sensibilité montre que le choix de la stratégie QBR ou HBR doit tenir compte des dimensions réelles des bassins et de leur emplacement sur le bassin versantReal time control (RTC) is considered as a cost-efficient solution for combined sewer overflow (CSO) reduction as it optimises the available capacity of sewer networks. RTC helps to prevent the need for construction of additional retention volumes, increases the network adaptability to changes in water management policies, and above all alleviates the environmental impact of CSOs. Following increasing interest in water quality-based RTC (QBR), this thesis demonstrates a simple and nothing-to-lose QBR strategy to reduce the amount of CSO loads during storm events. The performance of the QBR strategy, based on Mass-Volume (MV) curves prediction, is evaluated by comparison to a typical hydraulics-based RTC (HBR) strategy. A proof-of-concept study is first performed on a small catchment of 205 ha to test the new QBR concept using 31 storm events during a two-year period. Compared to HBR, QBR delivers CSO load reduction for more than one third of the events, with reduction values from 3 to 43 %. The QBR strategy is then implemented on the Louis Fargue catchment (7700 ha) in Bordeaux, France and similarly compared with the HBR strategy. By implementing QBR on 19 storm events over 15 months, its performance is consistent, bringing valuable benefits over HBR, with 17 out of 19 events having load reduction varying between 6 and 28.8 %. The thesis further evaluates the impact of MV curve prediction uncertainty (due to model prediction uncertainty) on the performance of the QBR strategy, using a representative storm event. The resulting range of uncertainty is limited. Besides, results of the sensitivity study show that the choice of the QBR or HBR strategy should take into account the current tank volumes and their locations within the catchment
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Fountoukis, Christos. "Modeling Aerosol - Water Interactions in Subsaturated and Supersaturated Environments." Diss., Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/16242.
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The current dissertation is motivated by the need for an improved understanding of aerosol water interactions both in subsaturated and supersaturated atmospheric conditions with a strong emphasis on air pollution and climate change modeling. A cloud droplet formation parameterization was developed to i) predict droplet formation from a lognormal representation of aerosol size distribution and composition, and, ii) include a size-dependant mass transfer coefficient for the growth of water droplets which explicitly accounts for the impact of organics on droplet growth kinetics. The parameterization unravels most of the physics of droplet formation and is in remarkable agreement with detailed numerical parcel model simulations, even for low values of the accommodation
coefficient. The parameterization offers a much needed rigorous and computationally inexpensive framework for directly linking complex chemical effects on aerosol activation in global climate models.
The new aerosol activation parameterization was also tested against observations from highly polluted clouds (within the vicinity of power plant plumes). Remarkable closure was achieved (much less than the 20% measurement uncertainty). The error in predicted cloud droplet concentration was mostly sensitive to updraft velocity. Optimal closure is obtained if the water vapor uptake coefficient is equal to 0.06. These findings can serve as much needed constraints in modeling of aerosol-cloud interactions in the North America.
Aerosol water interactions in ambient relative humidities less than 100% were studied
using a thermodynamic equilibrium model for inorganic aerosol and a three dimensional air quality model. We developed a new thermodynamic equilibrium model, ISORROPIA-II, which predicts the partitioning of semi-volatiles and the phase state of K+/Ca2+/Mg2+/NH4+/Na+/SO42-/NO3-/Cl-/H2O aerosols. A comprehensive evaluation of its performance was conducted against the thermodynamic module SCAPE2 over a wide range of atmospherically relevant conditions. Based on its computational rigor and performance, ISORROPIA-II appears to be a highly attractive alternative for use in large scale air quality and atmospheric transport models.
The new equilibrium model was also used to thermodynamically characterize aerosols measured at a highly polluted area. In the ammonia-rich environment of Mexico City, nitrate and chloride primarily partition in the aerosol phase with a 20-min equilibrium timescale; PM2.5 is insensitive to changes in ammonia but is to acidic semivolatile species. When RH is below 50%, predictions improve substantially if the aerosol follows a deliquescent behavior.
The impact of including crustal species (Ca2+, K+, M2+) in equilibrium calculations within
a three dimensional air quality model was also studied. A significant change in aerosol
water (-19.8%) and ammonium (-27.5%) concentrations was predicted when crustals are
explicitly included in the calculations even though they contributed, on average, only a
few percent of the total PM2.5 mass, highlighting the need for comprehensive thermodynamic calculations in the presence of dust.
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Mgcoyi, Bulelani William. "Quality assessment of agricultural water used for fertigation in the Boland district." Thesis, [Bloemfontein?] : Central University of Technology, Free State, 2011. http://hdl.handle.net/11462/174.
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Thesis (M. Tech. (Agriculture)) -- Central University of Technology, Free state, 2011Quality assessment of agricultural water used for fertigation in the Boland district. The study was undertaken to determine the influence of seasonal changes on the water quality (chemical and microbial analyses) of five different rivers in the Boland. The data was collected in the five most important water sources that are used for irrigation purposes in the district, i.e. Berg river, Eerste river, Klapmuts River, Klippies river and Krom river. The samples were collected from all sites once every three weeks for a period of six months. The sampling was carried out during specific periods in summer (December, 2006 to February, 2007) and winter (June to August, 2007). The results of the study showed that Klapmuts river recorded the highest levels of chloride and iron, especially in summer. However, chloride levels were far below the levels set by the Department of Water Affairs and Forestry. Results obtained from this study show the presence of pathogens in some of the rivers assessed which may have resulted from the leaching of these pathogens from nearby agricultural land, livestock watering or informal settlements in the catchment areas. The bigger rivers recorded low levels of micro-elements and this might have been affected by winter rainfall. In the Berg River, many sources of nitrate pollution seem to be present in the catchment area. The levels of iron in all the rivers assessed were far more than the levels set by the Department of Water Affairs and Forestry in all rivers assessed and these might be due to the pH levels and interaction between the rivers and seasons. Iron and manganese levels should be kept low as this may cause production problems by blocking irrigation drippers. The water samples tested for bacterial and fungal density showed Klapmuts and Eerste rivers were positive for Phytophthora cinnamomi during winter. Phytophthora citricola and Phytophthora cactorum were detected in the Klapmuts and Klippies rivers in summer. The Berg-, Klapmuts-, Krom- and Eerste rivers tested positive for species of the genera Pythium and Fusarium. Similar organisms were detected in the Eerste river mainly during summer on the fourth sampling date, while Krom river only tested positive for Pythium during summer. The total bacterial and algal density differed significantly between the seasons and was highest in winter. This might be due to high rain water influx and efflux and/or moist and aerobic conditions and air temperature. There is an increased need for farmers to sterilize feeding water (chlorination) due to high microbial count.
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Ratikane, Mosepeli. "Quality of drinking water sources in the Bloemfontein area of the Mangaung Metropolitan Municipality." Thesis, Bloemfontein : Central University of Technology, Free State, 2013. http://hdl.handle.net/11462/210.
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Thesis (M. Tech. (Environmental Health)) -- Central University of technology, Free State, 2013Introduction: Drinking water of poor quality can cause a variety of diseases and may even result in death. The impact of poor drinking water is a course for concern even in South Africa. Therefore, the physical, chemical and microbiological drinking water quality was investigated in the peri-urban area of Bainsvlei and the Woodlands Hills Estate in Bloemfontein, Free State. Materials and Methods: The water quality was assessed in 20 identified sampling sites for three series with ten weeks apart. These sites use treated municipal and untreated borehole water for drinking. The determinants analysed for were pH, electrical conductivity (EC), turbidity, temperature, Ca, Mg, Na, F, Cl, N, SO₄,N, Free chlorine, Al, As, CN, Fe, Mn, Pb, Hg, total coliforms and E. coli. The water samples were collected and analysed on site and in the laboratory. Both the physical and chemical determinants were measured using standard methods whereas the microbiological determinants were measured using the Defined Substrate Technology (DST) method. The measurements were first compared to the SANS 241 (2011) for compliance. The ANOVA tests were used to investigate if any seasonal variations existed in the water quality as well as to compare the levels of the determinants between borehole and municipal water. In the assessment of the overall drinking water quality of different water sampling sites the water quality index (WQI) was used. Results and Discussions: Significant effects were believed to exist if the p-values of the ANOVA and Scheffe tests were at a significance level of 5% (p < 0.05). The study results revealed that of the four physical determinants that were measured turbidity exceeded the standard in many sampling sites in the three series. Of all the chemical determinants, nitrates exceeded the standard. In the same way coliforms exceeded the standard in a number of sampling sites while E. coli was found in a few sampling sites in the first series. ANOVA tests revealed that seasonal variations existed between pH, EC, temperature, cyanide and iron at a significant level of 5% (p < 0.05) while the Post-hoc Scheffe test further revealed the series in which the effect existed. Similarly, the ANOVA tests revealed that the levels of the determinants between municipal versus borehole varied in pH, EC, Ca, Mg, Na, F, Cl, N, and SO₄ at a significant level of 5% (p < 0.05). The WQI showed that in all the series when combining the good and excellent category season 2 had the highest percentage of 80%, followed by season 3 with 79% and season 1 with 70%. Only borehole sampling sites were found in the poor, very poor and unsuitable categories. Similarly all the highest WQI values were found in borehole sampling sites. Conclusion: This study revealed that the water quality is of good quality in the Bainsvlei and Woodlands Hills Estate of the Mangaung metropolitan municipality in Bloemfontein, in the Free State, South Africa. The presence of E. coli, though found in a few sampling sites and the high levels of turbidity, nitrates and coliforms are of concern to public health.
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McKillip, Michael Lee. "Coupling the Hydrodynamic and Water Quality Model CE-QUAL-W2 With a Multi-Trophic Fish Bio-Energetics Model for Lake Roosevelt, Washington." PDXScholar, 2008. https://pdxscholar.library.pdx.edu/open_access_etds/3078.
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Grand Coulee Dam created Franklin D. Roosevelt Lake as part of the Columbia Basin Project. Located in northeastern Washington State, the Project provides economically important hydropower (19 billion kilowatt hours per year), irrigation (225,000 ha), flood control, and sport fishing ($5 to 20 million annually). A good system understanding aids in balancing these beneficial uses for the 230 km long reservoir. The reservoir's atypical 45-day mean residence time is much shorter than a typical lake, and much longer than for a riverine dam. The spring freshet requires drawdowns of 15 to 20 m for flood control—the driving characteristic of reservoir operations.
A physically based two-dimensional hydrodynamic and water quality model, CE-QUAL-W2 Version 3.5 (Cole and Wells, 2006), is coupled with a fish bioenergetics model based on the Stockwell and Johnson model (1997, 1999) to examine the effects of hydrodynamics on the reservoir algae-zooplankton-kokanee food web. This model was applied and calibrated to Lake Roosevelt with model improvements of multiple zooplankton compartments and zooplankton omnivory. Calibration parameters included temperature, dissolved oxygen, nutrients, algae, and zooplankton. The fish bioenergetics model is applied over the entire reservoir model space to generate a spatial and temporal fish growth potential distribution. The fish model refinements include sub-daily time-steps and an optimized vertical foraging strategy.
The linked model suggests that kokanee fish growth potential is seasonally limited by both warm water and prey densities. While the lake ecology is significantly affected by the reservoir operations in general, the pelagic fish growth potential did not appear sensitive to minor changes in reservoir operations. However, the model suggests that the advantageous foraging locations shift seasonally and that optimal foraging strategies are dependent on fish size.
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Zhang, Xi. "SPATIAL ESTIMATION OF HYDRAULIC PROPERTIES IN STRUCTURED SOILS AT THE FIELD SCALE." UKnowledge, 2019. https://uknowledge.uky.edu/pss_etds/117.
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Improving agricultural water management is important for conserving water during dry seasons, using limited water resources in the most efficient way, and minimizing environmental risks (e.g., leaching, surface runoff). The understanding of water movement in different zones of agricultural production fields is crucial to developing an effective irrigation strategy. This work centered on optimizing field water management by characterizing the spatial patterns of soil hydraulic properties. Soil hydraulic conductivity was measured across different zones in a farmer’s field, and its spatial variability was investigated by using geostatistical techniques. Since direct measurement of hydraulic conductivity is time-consuming and arduous, pedo-transfer functions (PTFs) have been developed to estimate hydraulic conductivity indirectly through more easily measurable soil properties. Due to ignoring soil structural information and spatial covariance between soil variables, PTFs often perform unsatisfactorily when field-scale estimations of hydraulic conductivity are needed. The performance of PTFs in estimating hydraulic conductivity in the field was therefore critically evaluated. Due to the presence of structural macro-pores, saturated hydraulic conductivity (Ks) showed high spatial heterogeneity, and this variability was not captured by texture-dominated PTF estimates. However, the general spatial pattern of near-saturated hydraulic conductivity can still be reasonably generated by PTF estimates. Therefore, the hydraulic conductivity maps based on PTF estimates should be evaluated carefully and handled with caution. Recognizing the significant contribution of macro-pores to saturated water flow, PTFs were further improved by including soil macro-porosity and were proven to perform much better in estimating Ks compared with established PTFs tested in this study. Additionally, the spatial relationship between hydraulic conductivity and its potential influencing factors were further quantified by the state-space approach. State-space models outperformed current PTFs and effectively described the spatial characteristics of hydraulic conductivity in the studied field. These findings provided a basis for modeling water/solute transport in the vadose zone, and sitespecific water management.
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Khetsha, Zenzile Peter. "The effect of potassium and water quality on the yield and oil quality of Rose Geranium (Pelargonium graveolens L.)." Thesis, Bloemfontein : Central University of Technology, Free State, 2013. http://hdl.handle.net/11462/189.
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Thesis (M. Tech. (Agriculture)) -- Central University of Technology, Free state, 2014The main objective of the study was to determine the effect of different potassium concentrations and water quality (salt) compared with the current scientifically accepted potassium threshold level and standardised water quality on the yield, oil composition and leaf morphology of rose geranium (Pelargonium graveolens L.) when grown in different potting-bag sizes and root media under temperature controlled condition. To achieve this objective, two trials were conducted. The first experiment evaluated potassium concentrations at 1.3, 3.3, 5.3 and 7.3 mmol L-1 and potting-bag size of 5 and 10 L. Treatments were arranged in a randomised complete block design assigned in a split plot layout. The main plots consisted of potassium concentration and the pottingbag sizes were allocated to sub-plots. Plant height, potassium content, linalool, geraniol, geranyl formate and the citronellol to geraniol ratio (C:G) were affected by potassium. Plant height, number of branches, the branch to height ratio (B:H), foliar fresh mass (FFM) and oil yield were significantly increased when 5 L potting bags were used. Plant foliar mass was significantly increased by the interaction between 5.3 mmol K L-1 and 5 L potting bags. In the second experiment salt levels applied at 1.6, 2.4, 3.2 and 4.0 mS cm-1 and root media (sand and sawdust) were evaluated. A split plot experimental layout was also used in this trial, with the salt levels allocated to the main plots. The sub-plots were allocated to the root medium. High salt level of 4.0 mS cm-1 reduced the number of leaves, plant height, number of branches, B:H ratio, leaf area, chlorophyll content and foliar fresh mass significantly. The number of leaves, leaf area and FFM were significantly increased where sawdust was used. Time of the day significantly affected stomatal conductance, and the opening of most stomata occurred at 10:00. Geranyl formate and the C:G ratio were significantly affected by salt at 4.0 mS cm-1. Salt induced the development of capitates trichomes. The abaxial leaf surface had a higher number of trichomes than the adaxial leaf surface. A strong polynomial (r2=0.97) relationship was found between capitates trichomes and salt levels. High densities of capitates trichomes were found at high salt level of 4.0 mS cm-1. Although the development of asciiform trichomes was induced, it was at an insignificant level. Trichome densities are therefore not affected by salt. It was therefore concluded that the application of 5.3 mmol K L-1 concentration and the use of 5 L potting bags improves the yield and oil quality of rose geranium. It was evident from this study that rose geranium might Salt induced have some degree of tolerance to salt. It was therefore concluded that rose geranium is a moderately salt-sensitive crop.
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McIlwain, Jason Andrew. "Hydrogeologic assessment of a proposed reservoir site, Smith County, Mississippi." Master's thesis, Mississippi State : Mississippi State University, 2007. http://library.msstate.edu/etd/show.asp?etd=etd-02282008-134137.
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Howard, Amanda Kelly. "Influence of instream physical habitat and water quality on the survival and occurrence of the endangered Cape Fear shiner." Connect to this title online, 2003. http://www.lib.ncsu.edu/theses/available/etd-04152003-213732/.
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Cristan, Richard. "Effectiveness of State Developed and Implemented Forestry Best Management Practices in the United States." Diss., Virginia Tech, 2016. http://hdl.handle.net/10919/71657.
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The passage of the Federal Water Pollution Control Act of 1972 required states to develop forestry BMPs to help reduce potential nonpoint source pollution from forest operations. Properly applied forestry best management practices (BMPs) have since been proven to protect water quality from forest operations. This research project reviewed BMP effectiveness studies in the U.S., assessed current state developed and implemented of forestry BMPs, and developed a simple method to estimate potential erosion from forest operations for the Piedmont physiographic region based on previous studies.
Eighty-one BMP effectiveness studies were reviewed. The review of past effectiveness studies indicates that water quality protection is increased when BMPs are implemented correctly. These effectiveness studies provide states with valuable information on how their BMP guidelines are achieving the goals defined by the Federal Water Pollution Control Act.
Every U.S. state has forestry BMP guidelines. These guidelines may be non-regulatory, quasi-regulatory, or regulatory depending on the state. Twenty states reported implementing non-regulatory BMP guidelines, 19 quasi-regulatory BMP guidelines, and 11 regulatory BMP guidelines. State forestry agencies were reported as being the lead agency responsible for BMP monitoring in 35 states. The national forestry BMP implementation rate was 91% (32 states). However, states did report deficiencies for specific BMP guideline categories. Supplementary to the reviewed BMP effectiveness studies, forest erosion studies in the southeastern U.S. that quantified erosion rates from forest operations were also reviewed. Erosion rates obtained from the literature were reviewed by operation categories (timber harvesting, forest roads, skid trails, log landings, stream crossings, and streamside management zones) and physiographic region (Mountains, Piedmont, Gulf Coastal Plain, and Atlantic Coastal Plain). There were numerous research gaps regarding erosion rates from forest operations for all the regions except the Piedmont region. The Piedmont region was selected for developing a method to estimate potential erosion from forest operations. This erosion estimation method is a quick and potentially useful tool for estimating potential erosion; however, it is based on limited data from the Piedmont region only. The basic method approach might be considered for the other physiographic regions, but further research is needed to fill current knowledge gaps.Ph. D.
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Lee, Saem [Verfasser], and Thomas [Akademischer Betreuer] Koellner. "Estimation of the economic trade-offs between farmers and consumers for water quality improvement in Soyang watershed, South Korea / Saem Lee ; Betreuer: Thomas Koellner." Bayreuth : Universität Bayreuth, 2018. http://d-nb.info/1156326516/34.
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Westerberg, Ida. "Observational Uncertainties in Water-Resources Modelling in Central America : Methods for Uncertainty Estimation and Model Evaluation." Doctoral thesis, Uppsala universitet, Luft-, vatten och landskapslära, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-152074.
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Knowledge about spatial and temporal variability of hydrological processes is central for sustainable water-resources management, and such knowledge is created from observational data. Hydrologic models are necessary for prediction for time periods and areas lacking data, but are affected by observational uncertainties. Methods for estimating and accounting for such uncertainties in water-resources modelling are of high importance, especially in regions such as Central America. Observational uncertainties were addressed in three ways in this thesis; quality control, quantitative estimation and development of model-evaluation techniques that addressed unquantifiable uncertainties. A first step in any modelling study should be the quality control and concurrent analysis of the representativeness of the observational data. In the characterisation of the precipitation regime in the Choluteca River basin in Honduras, four different quality problems were identified and 22% of the daily data had to be rejected. The monitoring network was found to be insufficient for a comprehensive characterisation of the high spatiotemporal variability of the precipitation regime. Quantitative estimations of data uncertainties can be made when sufficient information is available. Discharge-data uncertainties were estimated with a fuzzy regression for time-variable rating curves and from official rating curves for 35 stations in Honduras. The uncertainties were largest for low flows, as a result of measurement uncertainties and natural variability. A method for calibration with flow-duration curves was developed which enabled calibration to the whole flow range, accounting for discharge uncertainty and calibration with non-overlapping time periods for model input and evaluation data. The method compared favourably to traditional calibration in a test using two models applied in basins with different runoff-generation processes. A post-hoc analysis made it possible to identify potential model-structure errors and periods of disinformative data. Flow-duration curves were regionalised and used for calibration of a Central-American water-balance model. The initial model uncertainty for the ungauged basins was reduced by 70%. Non-representative precipitation data were found to be the main obstacle to comprehensive regional water-resources modelling in Central America. These methods bridged several problems related to observational uncertainties in water-balance modelling. Estimates of prediction uncertainty are an important basis for all types of decisions related to water-resources management.Kännedom om hur hydrologiska processer varierar i tid och rum är grundläggande för hållbar vattenresursförvaltning och skapas utifrån observerade data. Hydrologiska modeller är nödvändiga för att förutsäga vattenbalansen för tidsperioder och områden utan data, men påverkas av observationsosäkerheter. Metoder för att hantera sådana osäkerheter i vattenresursmodellering är av stor betydelse i regioner såsom Centralamerika. Observationsosäkerheter hanterades på tre olika sätt i denna avhandling; kvalitetskontroll, kvantitativ uppskattning och utveckling av modellutvärderingsmetoder för beaktande av icke kvantifierbara osäkerheter. Ett viktigt första steg är kvalitetskontroll och samtidig analys av datas representativitet. Vid karaktäriseringen av nederbördsregimen i Cholutecaflodens avrinningsområde i Honduras identifierades fyra olika kvalitetsproblem och 22 % av data sorterades bort. Stationsnätet var otillräckligt för en fullödig karaktärisering av nederbördsregimens variationer i tid och rum. Dessa var mycket stora som ett resultat av komplexiteten hos de nederbördsgenererande mekanismerna. Kvantitativ uppskattning av observerade datas osäkerhet kan göras när tillräcklig information är tillgänglig. Osäkerheter i vattenföringsdata uppskattades dels vid beräkning av vattenföring med en oskarp regression för en tidsvariabel avbördningskurva, dels från en analys av officiella avbördningskurvor från 35 stationer i Honduras. Osäkerheten var i båda fallen högst vid låga flöden som ett resultat av högre mätosäkerheter samt större naturlig variabilitet än vid höga flöden. En metod för modellkalibrering med varaktighetskurvor utvecklades och gjorde det möjligt att kalibrera för hela flödesintervallet samtidigt, ta hänsyn till osäkerheter i vattenföringsdata samt kalibrera med icke överlappande driv- och utvärderingsdata. Metoden testades med två olika modeller i två avrinningsområden med olika avrinningsbildningsprocesser, och visade goda resultat jämfört med traditionell modellkalibrering. En post hoc-analys gjorde det möjligt att identifiera troliga modellstrukturfel och perioder med disinformativa data. Varaktighetskurvor regionaliserades och användes för kalibrering av en regional vattenbalansmodell för Centralamerika, varvid den initiala modellosäkerheten minskades med 70 %. Icke representativa nederbördsdata identifierades som det största hindret för regional vattenresursmodellering i Centralamerika. De metoder som utvecklades i detta arbete gör det möjligt att överbrygga ett flertal problem orsakade av bristfällig tillgänglighet och kvalitet av data och leder därmed till en förbättrad uppskattning av osäkerheten i vattenbalanssimuleringar. Sådana osäkerhetsskattningar är ett viktigt underlag vid alla typer av förvaltningsbeslut som rör vattenresurser.