The upgrade of urban water distribution systems (UWDS) amidst uncertain global change pressures is a challenging problem. To deal with this dilemma water utilities require approaches that enable UWDS to be transitioned at a minimal technical and socio-economic impact as uncertainties become known. A review of approaches for upgrading UWDS shows that existing cost models are skewed towards operation and maintenance costs without consideration for future transitionability. This thesis describes approaches for the sustainable transition of UWDS and their application on case studies. The thesis develops a conceptual framework for the analysis of UWDS transitions. It then develops a Socio-economic Impact Indicator (SII) framework based on Multi Criteria Decision Analysis and the Analytical Hierarchical Process to estimate impacts in an urban area due to UWDS transitions. It also develops an approach for modelling socio-technical transitions based on multinomial logistic regression. The thesis then develops an UWDS transition design approach that considers not only operation and maintenance costs (leakage and burst costs) but also transitionability and future socio-technical impacts costs. The developed approaches have been tested on case studies as proof of concept. Maximum cost saving can be realised when existing UWDS are upgraded with consideration of future UWDS transitionability.

Accurate modelling, both numerical and physical, is vital to further our understanding of flow in rivers. This thesis examines both methods of flow applied to two distinct problems; numerical modelling of flow in simple channels with heterogeneous roughness and physical modelling of flow in compound channels with skewed floodplains. In this thesis, the Shiono and Knight Method (SKM) is applied to homogeneously and heterogeneously roughened channels. The SKM is shown to be capable of accurately predicting the lateral distributions of depth-averaged velocity and boundary shear stress for both roughness types. Furthermore, the percentage shear force on the wall of a channel is accurately obtained for both roughness types and guidance is given as to the choice of the three calibration coefficients the model requires, namely f, l and G representing friction, eddy viscosity and secondary flow respectively. Finally, physical modelling has been undertaken on compound channels with skewed floodplains in addition to a full review of the work undertaken at a larger scale in the Flood Channel Facility. As a result appropriate expressions for shear force and apparent shear forces acting on the horizontal and vertical interfaces have been established.

The frequency and intensity of flooding has increased over the last few decades. The UK is not an exception, despite large amounts of money invested every year in flood risk management, flooding is a prevalent issue in the country causing millions of losses every year. In this thesis we contribute to debate on the economic valuation of flood risk in the UK from a household perspective using a non-market valuation approach from the housing market. In the first chapter we investigate the capitalisation of flood risk in property prices by means of a meta-analysis. In the second and third chapters we use a repeatsales specification of a hedonic model to investigate the capitalisation of flood defences and the effect of flooding in the price of properties in England. The results suggest that the current benefit estimates used by the UK Government to determine the allocation of resources to flood relief projects results in a misallocation of resources. We highlight the importance of rethinking the strategy for flood risk management in the UK. Our results provide a sound economic basis to guide the allocation of resources for flood alleviation strategies in a socially efficient way.

Data collected in a large scale laboratory wave flume by a research team using the autonomous bottom boundary layer rig, (STABLE) was the subject of this study. The near bed suspension processes were examined relating them to the hydrodynamics. The deployment of a number of sensors allowed the assessment of their individual performance including the analysis of the pump-sampling and acoustic concentration data. Wavelet analysis was applied to identify the influence of STABLE on the vortex ripples in the vicinity of the rig. It revealed that the modification of the ripple dimensions around STABLE's feet was very localised. Sediment suspension was found to be strongly correlated to wave groups. The measured concentrations and empirical models based on convective and diffusive entrainment mechanisms were compared. A model based on the jet like ejection of particles between a vortex pair was developed and showed that lifting of sediments up to ten ripple heights above the bed was possible. A second model, capable of simulating the pumping effect, included this entrainment process to simulate the suspension under wave groups taking the suspension history into account. The behaviour of neutrally buoyant particles in a laboratory wave flume was videoed and revealed jet like ejections and horizontal movement over two or more ripple wavelengths.

O objetivo deste trabalho foi analisar o comportamento hidráulico de sistemas de abastecimento de água (SDAA), via redes neurais artificiais (RNA). Tendo em vista que o uso de um modelo de simulação hidráulica é inviável para operações em tempo real em SDAA devido à carga computacional que impõe, a abordagem adotada visa capturar o seu conhecimento de uma forma mais eficiente por meio de uma RNA de camada oculta única. Desta forma os conjuntos de dados provenientes de simulações hidráulicas realizadas utilizando o conhecido e consagrado software EPANET combinando diferentes situações e avaliando as variáveis que compõem os dois sistemas distintos, foram tabuladas e inseridas em forma de rotinas de programação desenvolvidas na plataforma do software Scilab. Os conjuntos de dados (entradas e saídas) utilizados para treinar a RNA, foram divididos em conjuntos de treino, validação cruzada e testes, aplicada a dois SDAAs distintos. O primeiro denominado Anytown modificado tratou de um sistema hipotético, cuja finalidade foi avaliar a metodologia e fundamentar o conhecimento. Posteriormente aplicou-se a metodologia em outro SDAA, real e mais complexo, utilizado na conferência de calibração WDSA Water Distribution System Analysis, realizada na cidade de Tucson, Arizona (EUA) entre os dias 12 e 15 de setembro de 2010. Desta maneira foram obtidos valores simulados de potência energética consumida no bombeamento, níveis de reservação e pressões, muito próximos dos valores reais para os dois SDAAs estudados, comprovando que as RNAs identificadas podem ser consideradas ferramentas eficientes na substituição dos modelos de simulação hidráulica convencionais. / The objective of this study was to analyze the hydraulic systems of water supply (WSS), using artificial neural networks (ANN). Since the use of a hydraulic simulation model is impractical for real-time operations due to the computational load WSS imposing, the approach aims to capture their knowledge more efficiently through a single hidden layer of RNA. Thus the data sets from hydraulic simulations conducted using the known and established software EPANET combining different situations and evaluating the variables that make up the two different systems were tabulated and entered in the form of programming routines developed in Scilab software platform. The data sets (inputs and outputs) used to train the ANN, were divided into training sets, cross validation and testing, applied to two distinct WSS. The first called Anytown modified dealt with a hypothetical system, whose purpose was to evaluate the methodology and knowledge base. Later the methodology was applied in another WSS, real and complex, used in the calibration WDSA conference Water Distribution System Analysis, held in Tucson, Arizona (USA) between 12 and 15 September 2010. Thus were obtained simulated values of the power energy consumed in pumping, pressures and reservation levels very close to actual values for the two WSS studied, proving that the identified ANN can be considered effective tools to replace in the conventional hydraulic simulation models.

Seabed gouging by ice, also known as ice scouring, is a common feature of the Arctic and sub Arctic regions of the planet as well as in Antarctica. It is a phenomenon which occurs when ice moves while in contact with the seabed. Ice gouging is of economical significance due to the probability of disruption of seabed structures such as subsea pipelines. Small scale laboratory tests were conducted at 1g to investigate the scour force produced when a scaled iceberg model scours a test bed in dry and saturated conditions. The tests were conducted for a range of scour depths, scour widths, frontal rake angles and soil conditions to study the performance of a rigid indenter (iceberg keel) scouring a test bed. Furthermore, the tests were also conducted at various speeds to study the rate effect in sand. The effect of the drifting speed on the drag force was found to be important: a sandy seabed scoured by an iceberg with a mean drifting speed of 0.1 m/s can generate scour loads twice as large as the static loads. The methods used currently to predict ice scour loads consider only the static loads under drained conditions and these should be revised. The PIV (Particle Image Velocimetry) technique was utilized to study the sub-gouge deformation and the soil failure mechanism associated with ice gouging. The soil resistance and the sub gouge deformation results obtained in the laboratory were compared with centrifuge investigations (the PRISE and PIRAM programs) in order to examine the viability of extrapolating the results from the model scale to a prototype scale.

Estuaries are highly dynamic systems, subject to continuous morphological change, which results from complex interactions and feedbacks between the hydrodynamic processes, sediment transport processes and the ecology. The prediction of morphological change in estuaries is therefore difficult but is necessary to help protect a range of human interests and estuarine ecosystems. Existing methods use detailed process modelling (Bottom-Up methods) or rely on data analysis and the development simple equilibrium relationships (Top-Down methods). Bottom-Up methods are able to make accurate predictions of change over short timescales but suffer from long simulation times and an accumulation of errors when applied over medium and long timescales, while Top-Down methods are better suited for predicting long term trends in morphological behaviour. A need currently exists for new, improved methods to predict changes occurring over medium timescales (one year to several decades). This thesis presents a new, Cellular Automata based, estuarine morphodynamic model, which divides the estuary into an array of cells and uses simplified representations of the hydrodynamic and sediment transport processes together with empirical rules to represent salt marsh ecology. The model has been developed to focus on high level interaction and feedback effects between these processes in order to identify potential medium term morphological changes that may occur in response to environmental change or engineering works. The model has been tested using a series of sensitivity tests and idealised test scenarios for a simple generic estuary and was found to have successfully generated qualitatively realistic results. The model is robust and computationally very efficient. Further work is now needed to calibrate and verify the model using datasets from real estuaries. Future improvements may also include the addition of ocean waves, littoral wave driven sand transport and improvements to the methodology in order to further enhance the computational efficiency.

A aplicação de modelagem numérica para análise acidentes envolvendo derrames de óleo se tornou uma das principais ferramentas para o estudo deste tipo de impacto ambiental, auxiliando na previsão do deslocamento e permitindo maior eficácia nas formas de atuação nos processos de contingência do deslocamento da mancha. Estes pressupostos dão impulso ao desenvolvimento de pesquisa aplicada neste caso específico de estudo, ou seja, de modelação hidrodinâmica no Canal de São Sebastião em vários cenários através da utilização do módulo hidrodinâmico do software MIKE 21 da DHI, e da avaliação dos resultados gerados pela simulação através de comparação com o acompanhamento de eventos reais de espalhamento de manchas de óleo em acidentes antigos e com uma imagem de satélite simultânea a um derramamento. Foram avaliados sete eventos distintos onde ocorreram vazamentos de óleo no Canal de São Sebastião e a eles comparados às simulações hidrodinâmicas geradas pelo modelo em diferentes condições ambientais. Os resultados obtidos mostram que o deslocamento da mancha de óleo está condicionado preferencialmente pelo regime de ventos, estando bem correlacionados com os padrões hidrodinâmicos encontrados. A partir das diferentes situações apresentadas nas simulações, é possível estimar o sentido do deslocamento em acidentes futuros, dando subsídios nas ações de contenção dos efeitos deste tipo de acidente. / The application of numeric models for analysis of oil spill in the coastal environments becomes one of the most important ways to understand the behavior of the oil in this case of impact, giving subsides to the prediction of the displacement of the patches and allowing best efficiency in the control of the extension of the impact agent. These assumptions give thrust to the development of applied research in this work, which is defined by the knowledge of the different hydrodynamic conditions that compose the oceanographic structure in the São Sebastião Channel, by the utilization of the software MIKE 21 of the DHI (Danish Hydrodynamic Institute) and the comparison with historic cases of spill described in the literature. A satellite image was processed showing the real conditions of the spill, considering the physic-chemical changes and compared with the other data improve the evaluation process. Seven oil spills were studied and compared to the simulations, and there were generated six scenarios in different environmental conditions. The results show that the most important forcing of the environmental conditions of the oil patch is the wind, and the simulations agree well with the real processes. The hydrodynamic module of Mike 21 reveals an applicable tool for this kind of studies, giving sufficient information to reduce the impact of oil spill improving the oil spill contention.

This research aims to develop realistic solutions to enhance the efficiency of port operations. By conducting a comprehensive literature review on logistic problems at seaports, some important gaps have been identified for the first time. The following contributions are made in order to close some of the existing gaps. Firstly, this thesis identifies important realistic features which have not been well-studied in current academic research of berth planning. This thesis then aims to solve a discrete dynamic Berth allocation problem (BAP) while taking tidal constraints into account. As an important feature when dealing with realistic scheduling, changing tides have not been well-considered in BAPs. To the best of our knowledge, there is no existing work using meta-heuristics to tackle the BAP with multiple tides that can provide feasible solutions for all the test cases. We propose one single-point meta-heuristic and one population-based meta-heuristic. With our algorithms, we meet the following goals: (i) to minimise the cost of all vessels while staying in the port, and (ii) to schedule available berths for the arriving vessels taking into account a multi-tidal planning horizon. Comprehensive experiments are conducted in order to analyse the strengths and weaknesses of the algorithms and compare with both exact and approximate methods. Furthermore, lacking tools for examining existing algorithms for different optimisation problems and simulating real-world scenarios is identified as another gap in this study. This thesis develops a discrete-event simulation framework. The framework is able to generate test cases for different problems and provide visualisations. With this framework, contributions include assessing the performance of different algorithms for optimisation problems and benchmarking optimisation problems.

This dissertation investigated the physical and biogeochemical processes affecting the source, fate, and transport of sediment, carbon, and nitrogen within a highly-coupled fluviokarst system. Elemental and isotopic datasets were collected at surface and subsurface locations for both dissolved and particulate contaminant phases, new methodology regarding data collection was presented to the karst research community, an in-cave sediment transport model coupling physical transport with elemental and isotopic mass balances of carbon and nitrogen was formulated, pathway and process control on nitrate leaching from agricultural karst watersheds was assessed, and nitrate mobilization and fractionation were modeled using high frequency storm sampling and long-term low-flow sampling. Data and modeling results indicate that phreatic karst conduits are transport-limited during hydrologic events and experience subsurface deposition of labile, storm-injected sediment which is subsequently decomposed by heterotrophic bacteria. An estimated 30% of the organic carbon associated with sediment is decomposed during transport in the subsurface karst. Concentrations of nitrate in subsurface waters are consistently 50% greater than surface inputs suggesting an additional source of subsurface nitrate. Further modeling of nitrate leaching indicates that quick-flow water sources dilute nitrate concentrations and slow-flow (epikarst and phreatic) sources account for approximately 90% of downstream nitrate delivery. Field sampling of extreme events highlights the physical transport and delayed release of high nitrate concentrations by intermediate karst pathways, which is likely associated with a transition from epikarst to soil drainage during storm recession. Modeling of sediment carbon and nitrogen within the karst SFGL supports the idea that the cave sediment bed experiences hot spots and hot moments of biogeochemical activity. Sediment nitrogen tracing data show a significant increase in δ15NSed at the spring outlet relative to karst inputs indicating the potential for isotope fractionation effects during dissolved N uptake by cave biota. Dissolved nitrogen stable isotopic composition shows a significant downstream decrease in δ15NNO3 within the conduit, likely associated with nitrification. Data and modeling results of sediment, carbon, and nitrogen emphasize the role of multiple pathways, turbulent transport, and in-conduit transformations in controlling contaminant flux from karst watersheds.