This thesis describes a study of the application of linear programming, a mathematical optimization technique, to the problem of operating a system of flood control reservoirs in the most efficient way for maximum flood peak reduction. The reservoir system studied was one which is proposed for flood control in the Fraser River Basin and for which preliminary designs have been made. The proposed sites are in the headwater areas of the river basin, remote from the area to be protected. A channel routing method which was linear was required for use with the linear programming technique. A method was developed which was based on monoclinal wave theory. Several different cases were studied in which the reservoir capacities and combinations of reservoirs included in the system were varied. The results show the maximum regulation which is available from each combination of reservoirs and identify the minimum storage capacities required at each site. Application of the technique in planning studies and in real-time reservoir operation is discussed. / Applied Science, Faculty of / Civil Engineering, Department of / Graduate

Orientador: Alberto Luiz Francato / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Civil, Arquitetura e Urbanismo / Made available in DSpace on 2018-08-26T14:59:45Z (GMT). No. of bitstreams: 1 Costa_CarlosAntonioSeverino_M.pdf: 4423494 bytes, checksum: efb5bbedc885642da6b53bdbca912fc4 (MD5) Previous issue date: 2014 / Resumo: O controle de cheias no Brasil e no mundo tem sido alvo de estudo nos centros de pesquisa e um desafio para os governantes. As inundações em muitos países têm sido consideradas como um dos maiores desastres naturais. Anualmente, centenas de bilhões de dólares de prejuízos crescentes vêm se verificando em todo o mundo, devido aos riscos cada vez maiores às benfeitorias, culturas agrícolas, obras de infraestrutura, populações ribeirinhas, áreas urbanas etc. Centros de pesquisas de todo o mundo têm abordado o assunto e proposto medidas de controle a inundação, tanto estruturais como não estruturais. Novas metodologias para operação de reservatórios, buscando sua melhor capacidade de controle das cheias e ao mesmo tempo atendendo aos outros usos da água, têm sido apresentadas de modo a minimizar os impactos das cheias e, por conseguinte, reduzir riscos e prejuízos junto às comunidades. A motivação desta dissertação foi desenvolver uma metodologia que possa avaliar o custo hidroenergético da manutenção de volumes de espera para o controle de cheias nos reservatórios, mais especificamente em estabelecer uma política de armazenamento das cheias de forma a minimizar os impactos para a geração de energia hidrelétrica. Tal tarefa foi realizada utilizando o modelo CooperMax (FRANCATO, 2014), com adaptações para a análise de cheias / Abstract: Flood control in Brazil and abroad has been studied in research centers and has posed a challenge to governments. Floods in many countries have been regarded as one of the greatest natural disasters. Every year hundreds of billions of dollars of rising losses have been observed around the world due increasing risks to property, crops, infrastructure, river populations, urban areas etc. Research centers around the world have approached the subject and proposed flood control measures, both structural and non-structural. New methodologies for reservoir operation for better flood controls, taking into account other uses of water, have been proposed in order to minimize the impact of flood and therefore reduce risks and losses in the communities. The motivation of this thesis was to develop a methodology to evaluate the hydropower cost of maintaining a storage volume for flood control in the reservoirs, more specifically in establishing a policy of flood storage in order to minimize impacts in hydropower generation. This task was performed using the CooperMax model, adapted for the analysis of floods / Mestrado / Recursos Hidricos, Energeticos e Ambientais / Mestre em Engenharia Civil

Few genomic and metagenomic studies have focused on freshwater systems in the last years. Most of the studies carried out on these particular environments so far rely on microscopy, physiology, phenotypic observations, individual genes and 16S rRNA sequencing. Here, we shed light on microbial communities from oligotrophic and mesotrophic freshwater systems using high-throughput deep sequencing metagenomics and genome-resolved metagenomics. We have focused on the study of ubiquitous and cosmopolitan microbial groups from two temperate Spanish reservoirs (Tous, Amadorio). Among these, we studied freshwater picocyanobacteria from Synechococcus and Cyanobium genera, which so far have not been well characterized at the genomic level, compared to the marine representatives. In particular, we were able to isolate two of the most abundant picocyanobacteria from Tous reservoir, which were previously studied via metagenomics. These picocyanobacteria are not only abundant in this reservoir but are widely distributed in different freshwater and brackish systems. In this work we also shed light on some of the first freshwater representatives of the phylum Verrucomicrobia, that are ecologically uncharacterized in freshwater systems about which relatively little is known. We discovered a wide range of metabolisms in these microbes, ranging from nitrogen fixation and photoheterotrophy via rhodopsin pumps to important contributions in the degradation of recalcitrant matter and polysaccharides. We also include the first metagenomic study of the microbial communities under the ice waters of the largest (by volume) ultraoligotrophic lake in the world, Lake Baikal. This study has provided a first glimpse and a particular microbial composition on the sub-ice, having found an unusual fraction of Verrucomicrobia and new microbial lineages from many typical freshwater phyla, including the first freshwater representative of the groups I/II of SAR11 lineage and novel genomes of Proteobacteria, Thaumarchaeaota, Gemmatimonadetes, Cyanobacteria, Planctomycetes, Bacteroidetes, Acidobacteria, Nitrospirae, Verrucomicrobia or Actinobacteria.

Lake Manassas is an approximate 706 acre man-made lake located in greater Prince William County near the town of Gainesville, Virginia. The lake was created in 1968 on Broad Run to serve as the primary water supply for the City of Manassas and its residents. The Lake Manassas watershed lies within the greater Occoquan River watershed which drains into the Potomac River and Chesapeake Bay. Water within Lake Manassas and its tributaries has been monitored since 1971 and this thesis presents a comprehensive limnological analysis of the Lake with an analysis of water quality impacts over time. Lake Manassas remains an enriched or eutrophic system, meaning the levels of nutrients and biomass production in lake waters is above desired standards. Nutrient loading occurs via a stream network with the largest contributor being Broad Run which is consistent with previous water quality studies. The lake serves as the sole water source for nearly 40,000 residents and businesses and ensuring clean and safe water is of significant importance. Close monitoring in conjunction with the implementation of appropriate management practices within the watershed are necessary to prevent water quality from becoming significantly degraded. / Master of Science

No description available.

Geologic sequestration of CO2 into unmineable coal seams is proposed as a way to mitigate the greenhouse gas effect and potentially contribute to economic prosperity through enhanced methane recovery. In 2009, the Virginia Center for Coal and Energy Research (VCCER) injected 907 tonnes of CO2 into one vertical coalbed methane well for one month in Russell County, Virginia (VA). The main objective of the test was to assess storage potential of coal seams and to investigate the potential of enhanced gas recovery. In 2014, a larger scale test is planned where 20,000 tonnes of CO2 will be injected into three vertical coalbed methane wells over a period of a year in Buchanan County, VA. During primary coalbed methane production and enhanced production through CO2 injection, a series of complex physical and mechanical phenomena occur. The ability to represent the behavior of a coalbed reservoir as accurately as possible via computer simulations yields insight into the processes taking place and is an indispensable tool for the decision process of future operations. More specifically, the economic viability of projects can be assessed by predicting production: well performance can be maximized, drilling patterns can be optimized and, most importantly, associated risks with operations can be accounted for and possibly avoided. However, developing representative computer models and successfully simulating reservoir production and injection regimes is challenging. A large number of input parameters are required, many of which are uncertain even if they are determined experimentally or via in-situ measurements. Such parameters include, but are not limited to, seam geometry, formation properties, production constraints, etc. Modeling of production and injection in multi-seam formations for hydraulically fractured wells is a recent development in coalbed methane/enhanced coalbed methane (CBM/ECBM) reservoir modeling, where models become even more complex and demanding. In such cases model simulation times become important. The development of accurate simulation models that correctly account for the behavior of coalbeds in primary and enhanced production is a process that requires attention to detail, data validation, and model verification. A number of simplifying assumptions are necessary to run these models, where the user should be able to balance accuracy with computational time. In this thesis, pre- and post-injection simulations for the site in Russell County, VA, and preliminary reservoir simulations for the Buchanan County, VA, site are performed. The concepts of multi-well, multi-seam, explicitly modeled hydraulic fractures and skin factors are incorporated with field results to provide accurate modeling predictions. / Ph. D.

Petrophysical properties are fundamental to understanding fluid flow processes in hydrocarbon reservoirs. Special Core Analysis (SCAL) routinely used in industry are time-consuming, expensive, and often destructive. Alternatively, easily available thin section data is lacking the representation of pore space in 3D, which is a requisite for generating pore network models (PNM) and computing petrophysical properties. In this study, these challenges were addressed using a numerical SCAL workflow that employs pore volume reconstruction from thin section images obtained from confocal laser scanning microscopy (CLSM). A key objective is to investigate methods capable of 2D to 3D reconstruction, to obtain PNM used for the estimation of transport properties. Representative thin sections from a well-known Middle-Eastern carbonate formation were used to obtain CLSM images. The thin-sections were specially prepared by spiking the resin with UV dye, enabling high-resolution imaging. The grayscale images obtained from CLSM were preprocessed and segmented into binary images. Generative Adversarial Networks (GAN) and Two-Point Statistics (TPS) were applied, and PNM were extracted from these binary datasets. Porosity, Permeability, and Mercury Injection Porosimetry (MIP) on the corresponding core plugs were conducted and an assessment of the properties computed from the PNM obtained from the reconstructed 3D pore volume is presented. Moreover, the results from the artificial pore networks were corroborated using 3D confocal images of etched pore casts (PCE). The results showed that based on visual inspection only, GAN outperformed TPS in mimicking the 3D distribution of pore scale heterogeneity, additionally, GAN and PCE outperformed the results of MIP obtained by TPS on the Skeletal-Oolitic facies, without providing a major improvement on more heterogeneous samples. All methods captured successfully the porosity while absolute permeability was not captured. Formation resistivity factor and thermal conductivity showcased their strong correlation with porosity. The study thus provides valuable insights into the application of 2D to 3D reconstruction to obtain pore network models of heterogeneous carbonate rocks for petrophysical characterization for quick decision. The study addresses the following important questions: 1) how legacy thin sections can be leveraged to petrophysically characterize reservoir rocks 2) how reliable are 2D to 3D reconstruction methods when predicting petrophysical properties of carbonates.

No description available.

The American cockroach, Periplaneta americana (L.), is an important urban pest due to its ability to invade residential and commercial structures from non-residential reservoirs. Extensive field studies were conducted in a large urban apartment complex, Lincoln Terrace (LT), managed by the Roanoke Redevelopment and Housing Authority (RRHA), in Roanoke, Virginia. Inspection in the RRHA-LT complex corroborated well with other researchers' finding that sewer and storm drainage systems are the principal reservoirs for P. americana population in the temperate urban environn1ent. Investigations provided new evidence that basements of the RRHA-LT apartment buildings served as secondary reservoirs for this pest species. Environmental and ecological parameters that characterize basements as important P. americana population reservoir foci were studied. Understanding how populations function in the urban environment is as important as identifying P. americana population reservoirs. Over two-years of fleld investigations demonstrated that foraging activity of P. americana was seasonal. A study of a simulated population of caged American cockroaches maintained in a basement environment confirmed that their foraging activity was seasonal. Foraging seasonality characterizes the seasonal pest status of this cockroach species in the temperate urban environment. Therefore, seasonally oriented control or management strategies for this pest species are proposed and discussed. Lipids, carbohydrates, and proteins of American cockroach adults were analyzed and quantified on a monthly basis for a year. Seasonal foraging activity was reflected by seasonal changes of metabolic reserves in this species. Low foraging activity in the colder, winter months characterized an overwintering period of P. americana populations in the urban environment. Lipids were the principal metabolic reserve for overwintering cockroaches, and accounted for a 22% of dry body weight loss in females and 18% in males. Proteins accounted for approximately 10% of the dry body weight loss for overwintering females and males. Glycogen concentration per unit dry weight increased 11 % to 15% during the overwintering period. This change suggests that glycogen may function as a cold hardiness substance rather than as a energy reserve during overwintering. Nutrient deficits of post-overwintering individuals in the population explained the underlying physiological driving force for significantly ir~creased foraging activities in the spring. Caged P. americana demonstrated a high reproductive potentia] in the basement environment. High reproductive rate created protein and lipid deficits in adults that required increased foraging for food and increased cannibalism of oothl!cae and young nymphs. Approximately 33% of the oothecae and 28% of nymphs were cannibalized in the caged population. / Ph. D.

The optimal reservoir operations problem consists of obtaining releases, storages of a reservoir and downstream reach routed flows such that benefits derived from operating the reservoir are maximized. These are obtained on the basis of forecasted inflows to the reservoir, and forecasted precipitation in the downstream reaches. Five goal programming schemes, namely (i) preemptive goal programming (ii) weighted goal programming (iii) minmax goal programming (iv) fuzzy goal programming and (v) interval goal programming are considered. The reservoir operation problem is also formulated as a multiobjective linear program (MOLP). It is shown that the optimal solutions of the goal programs are contained among the efficient points of the MOLP. It is also shown that the min max and fuzzy goal programs can yield inefficient points as optima; however, there exist alternate optima to these programs which are efficient. Therefore, it is suggested that one should solve an MOLP for considering alternative efficient solutions. These techniques are applied to the Green River basin system in Kentucky. / Master of Science