L’élaboration des Plans de Prévention des Risques Littoraux (PPRL) « prioritaires », définis suite à la tempête Xynthia de 2010, a provoqué des débats, souvent conflictuels, entre l’Etat et les collectivités territoriales au sujet des cartes d’aléas submersion marine ou recul du trait de côte. Cette recherche doctorale s’attache à la compréhension du processus de construction de ces cartes. Elle analyse les facteurs influençant cette cartographie à partir de ce que représentent les cartes d’aléas pour chaque acteur. Les résultats de cette recherche mettent en évidence que les études d’aléas sont peu issues des connaissances territoriales et abordées sous un angle expert complexe. Les acteurs locaux s’approprient ainsi difficilement les nouvelles connaissances sur les aléas littoraux. La forte présence des aspects techniques et la mécanique d’élaboration du zonage réglementaire conduisent à une cristallisation des débats des PPRL sur la cartographie des aléas. Ces débats cachent aussi souvent des conceptions distinctes de la politique de prévention et des intérêts divergents entre acteurs agissant à échelles spatiales et temporelles différentes. L’ouverture restreinte des discussions par l’Etat lors de la cartographie des aléas de référence et de l’élaboration du zonage conduit à une faible territorialisation des PPRL et rend difficile leur intégration au sein des politiques locales de prévention des risques littoraux et d’aménagement du territoire. Cette thèse révèle ainsi l’importance cruciale de la concertation et d’une entrée par le territoire, pour mettre en place une appropriation active des connaissances sur les aléas et favoriser l’intégration du PPRL au sein de l’action publique territoriale. / The development of Coastal risks prevention plans, identified as priorities after Xynthia storm in 2010, has revealed divisive debates, between the state services and territorial authorities, about coastal flooding or coastline recession mapping. This PhD research deals with the understanding of coastal hazards mapping. It analyses the factors which influence this process based on what do the maps represent for each stakeholder.The research results highlight that hazards studies sparsely come from territorial knowledge and are often approached from a complex expert angle. Thus, new knowledge is hardly managed by local stakeholders. Significant debates about technical aspects and the process of regulatory zoning conception lead to the fact that hazards mapping crystallizes the PPRL debates. Actually, these debates often hide different conceptions of prevention policy and opposing interests of stakeholders acting at different spatial and temporal scales. The few opened discussions purposed by state services during reference hazards mapping and zoning conception lead to a low territorialization of the PPRL and make their integration in local policies of coastal risks prevention and of land use planning difficult.Thus, this PhD highlights the crucial role of dialogue and of an input by the territory, in order to start an active appropriation of hazards knowledge and to enable the PPRL integration within the territorial public policy.

O aumento da inundação em áreas do baixo curso do rio Taquari, no Pantanal do estado do Mato Grosso do Sul, tem transformado a pecuária desta região numa atividade com baixa rentabilidade, à medida que extensas áreas de campo passaram a ser inundadas vários meses durante o ano a partir da década de 70. A pecuária realizada em campos naturais de regiões úmidas do Pantanal indica que há necessidade de se investigar metodologias apropriadas para avaliação de impacto ambiental, que abordem impactos diretos, indiretos, cumulativos e processos do meio físico que alteram, de maneira prejudicial, o meio ambiente. Supõe-se que a inundação na planície do rio Taquari esteja relacionada com a ocupação antrópica nas áreas de planalto da bacia do rio Taquari. O presente trabalho tem por objetivo avaliar os impactos ambientais na planície de inundação do baixo curso do Taquari, decorrentes da ocupação antrópica da bacia hidrográfica do rio Taquari em sua totalidade, considerando os impactos ambientais causados pela pecuária à medida que se configura como principal atividade econômica da bacia bem como os processos erosivos e de assoreamento no quadro atual do regime de inundações. As etapas de caracterização da área, de análise dos impactos e as propostas de ações mitigadoras, previstas num Estudo de Impacto Ambiental, foram aqui analisadas. Foram utilizadas informações sobre as características do meio físico, biótico e socioeconômico, selecionadas a partir do levantamento dos dados existentes com recorte efetuado para a bacia hidrográfica do rio Taquari. Na maior parte dos temas, este foi um processo de levantamento, ordenamento e recuperação de informações, na escala original de 1:250.000, do Plano de Conservação da Bacia do Alto Paraguai-PCBAP, gerenciado no SPRING. Foram também realizadas viagens de campo para a complementação dos dados e para o levantamento de atividades antrópicas com verificações \"in loco\" da ocorrência de impacto ambiental. A maioria dos dados socioeconômicos compilados para o presente trabalho teve por base os censos agropecuários e demográficos realizados pelo IBGE. Os resultados obtidos demonstram que os impactos ambientais decorrentes da pecuária no planalto interferem no regime de inundação na planície da bacia, o que só foi possível de ser identificado a partir de análises integradas em toda a bacia hidrográfica do rio Taquari. Verificou-se que os métodos de EIA são adequados para identificar os impactos diretos decorrentes da pecuária, mas não são adequados para identificar os processos e seus efeitos cumulativos na extensão da bacia hidrográfica do rio Taquari. Além disto, a abordagem da avaliação ambiental estratégica, como procedimento para análise ambiental em políticas, planos e programas, mostra-se adequada para as análises na BHRT à medida que está centralizada nos efeitos do ambiente sobre as necessidades e oportunidades de desenvolvimento. Contudo, somente a recuperação de danos ambientais, o controle das origens dos impactos no ambiente e um sistema de gestão consciente de seus compromissos podem levar, juntamente com a melhora dos procedimentos técnicos e administrativos para análises ambientais, à uma maior proximidade da sustentabilidade ambiental na BHRT. / The increase of flooding in the low course areas of Taquari river in the Pantanal - Mato Grosso do Sul state, has been transforming the cattle raising activity to a low profit activity in the region, when that extensive areas of pasture started to be flooded throughout several months a year from the 1970s. Since these areas are located in the Pantanal region where cattle raising activity is carried on in natural pasture it is necessary to investigate suitable methodologies for evaluation of the ambiental impact, approaching direct, indirect and cummulative impact as well as the processes that change, in a harmful way the environment. The flooding in the floodplain in Taquari river is supposed to be related to the anthropic ocupation in the upland areas of the Taquari river watershed. This work aims to evaluate the environmental impact caused by the anthropic ocupation, the cattle raising activity in the basin and the erosion and silting process in the flood plain of the Taquari river low course. The steps for the area characterization, the analysis of the impact and proposals viewing to diminish the problem, projected in an EIA (Environmental Impact Study), were also considered here. Information on the physical, biologic and socio-economic environment, selected from pre existent data survey, carried on for the Taquari river watershed (BHRT) were used here. For most of the themes, this was a process of surveying and recovering information in the original scale of 1:250.000 from the PCBAP managed in the SPRING GIS model. Field work to complement the existent data to survey the environmental impact of anthropic activities were also carried on. Most of socio-economic data used here were based on the cattle raising activity and demographic census data from IBGE. The results show that the environmental impact caused by cattle raising in the upland interferes in the flooding system in the watershed flood plain, and this fact could only be identified from the integrated analysis of the whole Taquari river watershed. It was observed that the EIA methods are suitable to identify the direct impact caused by the cattle raising activity, but they are not suitable to identify the process and its cummulative effects along the Taquari river watershed. Moreover, it was observed that the approach of the Strategic Environmental Assessment (SEA) as a procedure for environmental analysis in the policies, plans and programs is suitable for the analysis in the BHRT when it is centralized in the effects of environment on the necessities and opportunities of development. However, only the recovering of ambiental damage, the control of the effects caused by impacts on the environment and a system of conscient management can lead to an improvement in the technic and administrative procedures for a really possible ambiental sustentability in the BHRT.

Submitted by SBI Biblioteca Digital (sbi.bibliotecadigital@puc-campinas.edu.br) on 2017-01-03T16:21:29Z No. of bitstreams: 1 ALERTA PO? ? UM SISTEMA DE COMUNICA??O APOIADO EM REDES DE SENSORES SEM FIO PARA MONITORA??O DO C?RREGO ITAIM.pdf: 3373158 bytes, checksum: 31363a3d5310d22b8a185ceba8f3f1c6 (MD5) / Made available in DSpace on 2017-01-03T16:21:30Z (GMT). No. of bitstreams: 1 ALERTA PO? ? UM SISTEMA DE COMUNICA??O APOIADO EM REDES DE SENSORES SEM FIO PARA MONITORA??O DO C?RREGO ITAIM.pdf: 3373158 bytes, checksum: 31363a3d5310d22b8a185ceba8f3f1c6 (MD5) Previous issue date: 2016-11-25 / The problems of floods in Brazil cause many difficulties in the lives of many Brazilians throughout the country. Examples such as S?o Paulo, where during the summer the heavy rains, attached to infrastructure problems, enhance transit and leave homeless, or as Po? suffering almost every year with social problems arising from flooding revealing that the problem is recurrent. In this sense, to minimize financial losses and, above all, avoid loss of life (deaths), this work presents a development proposal to interconnect wireless sensor networks and the Internet using low-cost sensors for the level of streams monitoring and rivers urban. In this research the main objective is to provide a reliable system of monitoring streams of water level, crossing a city and contribute to the security of the population, built through the use of a network of sensors without low financial cost wire. The collected data is transmitted in real time to the City Security Control Center that treats these raw data and makes them available in useful information and easy viewing of the stream water level of the residents in the municipality of Po? through a page Web Prefecture. To increase agility in decision-making, information will also be available to citizens through an application installed on mobile devices (smartphones or tablets) that allows the current view of the percentage of water in the stream. The case study results showed the feasibility of implementing this proposal therefore be demonstrated that the water level in the stream monitoring using low cost sensors through a web page and application for mobile devices is possible. With the implementation of wireless sensor network citizens begin to monitor and be alerted to possible flooding, enabling the rescue of material goods and human lives. / Os problemas das enchentes no Brasil causam diversas dificuldades na vida de v?rios brasileiros em todo o territ?rio nacional. Exemplos como o de S?o Paulo, onde durante o ver?o o excesso de chuvas, unido a problemas de infraestrutura, intensificam o tr?nsito e deixam desabrigados, ou como de Po? que sofre praticamente todos os anos com problemas sociais decorrentes de enchentes revelando que o problema ? recorrente. Neste sentido, para minimizar preju?zos financeiros e, principalmente, evitar perda de vidas (mortes), este trabalho apresenta uma proposta de desenvolvimento para interconex?o de redes de sensores sem fio e a internet utilizando sensores de baixo custo para monitoramento do n?vel de c?rregos e rios urbanos. Nesta pesquisa o principal objetivo ? oferecer um sistema confi?vel de monitora??o do n?vel de ?gua de c?rregos, que atravessam uma cidade e que contribua com a seguran?a da popula??o, constru?do por meio do uso de uma rede de sensores sem fio de baixo custo financeiro. Os dados coletados s?o transmitidos em tempo real para o Centro de Controle de Seguran?a da Cidade que trata estes dados brutos e os disponibiliza em informa??es ?teis e de f?cil visualiza??o sobre o n?vel de ?gua do c?rrego aos cidad?os residentes no Munic?pio de Po? atrav?s de uma p?gina web da Prefeitura. Para aumentar a agilidade na tomada de decis?es, as informa??es tamb?m estar?o dispon?veis aos cidad?os por meio de um aplicativo instalado em dispositivos m?veis (smartphones ou tablets) que permite a visualiza??o atual da porcentagem de ?gua no c?rrego. Os resultados do estudo de caso apontaram para a viabilidade de implementa??o desta proposta, pois, demostrou-se que ? poss?vel o monitoramento do n?vel de ?gua no c?rrego utilizando sensores de baixo custo atrav?s de uma p?gina web e aplicativo para dispositivos m?veis. Com a implementa??o da rede de sensores sem fio os cidad?os passam a monitorar e a serem alertados sobre poss?veis enchentes, possibilitando o salvamento de bens materiais e de vidas humanas.

Parmi les risques naturels, le risque d’inondation est le plus fréquent et le plus dommageable en France avec près de 50 % des communes exposées. Dans le département du Haut-Rhin, c’est 80 % des communes qui sont concernées. L’absence d’étude historique approfondie sur les inondations en Alsace et plus particulièrement sur celles de la Lauch, théâtre des derniers grands évènements, a constitué la principale motivation quant au choix de ce sujet. A défaut de pouvoir éradiquer ce risque, l’Homme a, au cours de l’histoire, engagé des actions palliatives pour s’en prémunir. De quelle manière et dans quelle mesure, les évènements historiques ont-ils été pris en considération dans les politiques de gestion et de prévention du risque d’inondation mises en place dans la vallée de la Lauch, durant plus de deux siècles ? Pour répondre à cette problématique, nous avons eu recours à une approche diachronique, avec pour point de départ l’évènement funeste de février 1990, et adopté une démarche interdisciplinaire. S’appuyant sur un important corpus de sources, cette thèse met en perspective l’évolution de la gestion des inondations sur la période considérée en fonction des évènements hydrologiques restitués via une méthode régressive, des enjeux, des contextes politiques très contrastés, et des acteurs, tant au plan local, national, qu’européen. S’inscrivant dans une logique de démarche appliquée, cette étude a pour ambition d’améliorer l’information sur les phénomènes et de constituer un « socle de connaissances scientifiques » pour une meilleure maîtrise du risque. Ainsi, il paraît fondamental de connaître l’aléa afin de pouvoir l’anticiper, s’en prémunir et mieux le gérer. / Among the natural hazards, the flood risk is the most frequent and the most harmful in France with about 50 % of the municipalities exposed. In the Haut-Rhin department, 80 % of the municipalities are concerned. We have chosen this subject because no historic study exists about floods in Alsace and especially about the Lauch valley, where the last big events have taken place. In front of the impossibility to eradicate the risk, the Man committed palliative actions to protect himself through history. How have the historic events been taken into consideration in policies of management and prevention of the flood risk in the Lauch valley for more than two centuries ? To answer this question, we have used a diachronic approach which begins with the disastrous event of February 1990, and adopted an interdisciplinary method. Based on an important corpus of sources, this thesis puts in perspective the evolution of the management of the floods over the period considered according to the hydrological events restored via a regressive method, the stakes, the very contrasted political contexts and the actors, over the local, national and European plans. This thesis is part of a logic of applied reasoning and has for ambition to improve the information about the phenomena and to constitute a "basis of scientific knowledge" for a better control of the risk. This way, it seems fundamental to know flood hazard to be able to anticipate it, to manage it better and to protect ourselves.

This thesis investigates the effectiveness of Low Impact Development Infrastructure (LIDI) and Green Infrastructure (GI) in reducing flooding resulting from heavy rainfall events and sea-level rise, and in improving stormwater quality in the City of Miami Beach (CMB). InfoSWMM was used to simulate the 5, 10, and 100-year, 24-hour storm events, total suspended solids (TSS), biochemical oxygen demand (BOD), and chemical oxygen demand (COD) loadings, and in evaluating the potential of selected LIDI and GI solutions in North Shore neighborhood. Post-development results revealed a decrease of 48%, 46%, and 39% in runoff, a decrease of 57%, 60%, and 62% in TSS, a decrease of 82%, 82%, and 84% in BOD, and a decrease of 69%, 69%, and 70% in COD loadings. SWMM 5.1 was also used to simulate the king tide effect in a cross section in Indian Creek Drive. The proposed design simulations successfully demonstrated the potential to control flooding, showing that innovative technologies offer the city opportunities to cope with climate impacts. This study should be most helpful to the CMB to support its management of flooding under any adaptation scenarios that may possibly result from climate changes. Flooding could be again caused as a result of changes in inland flooding from precipitation patterns or from sea-level rise or both.

Throughout arid and semi-arid inland Australia, many extensive floodplains occur in association with rivers which are amongst the most hydrologically variable in the world. As rainfall in these areas is characteristically low and patchy, conditions in Australia's 'dryland' floodplains fluctuate unpredictably between extended periods of drought and huge floods that transform vast areas into wetlands, often for months at a time. Vegetation in these floodplains is commonly dominated by short grass and forb associations and patches of open succulent shrubland which are attributed with high ecological and socio-economic values due to their provision of habitat to a diverse array of terrestrial and aquatic fauna and their productive native pasture growth. In temperate and tropical floodplains, a substantial number of studies have shown that plant community composition and structure is determined primarily by flow and alterations to flow in these areas, through water extraction or river regulation, have resulted in many changes to the vegetation including loss of biodiversity and mass invasions of exotic species. Despite increasing pressure for water resource development in 'dryland' regions, relatively little is known regarding the effects of highly variable flows on the vegetation dynamics of arid floodplains, particularly in Australia. This thesis addresses this knowledge gap by examining the role of flow in the vegetation dynamics of a large arid floodplain in central Australia: the Cooper Creek floodplain. The effects of flow on plant community dynamics, from an organism level to that of the landscape, are examined across a range of spatial and temporal scales. Results are presented from a two year temporal vegetation survey during which time two flood pulse events of differing sizes occurred. A large-scale spatial survey was also conducted to determine the effects of flood history on spatial variation in plant community composition and structure. The composition of the soil seed bank and its contribution to vegetation dynamics were additionally investigated through a series of germination trials. Amongst common arid floodplain plants, life history traits that enable persistence under variable hydrological conditions were also considered via several experiments aimed at determining the effects of flow on the outcomes of various life history stages including germination, growth and dispersal. Throughout the study, results are presented for plant groups that were predefined on the basis of life form, life span and taxonomic divisions within these categories. Plant community composition and structure in the Cooper Creek floodplain exhibits significant shifts both temporally, in response to flood pulse wetting and drying, and spatially, in response to flood history. Flood pulse inundation has the potential to influence each life history stage across the range of plant groups present and the outcomes of these appear to be determined by hydrological attributes such as flood pulse timing, duration and rate of drawdown. Vegetation consequently exhibits gradual zonation on a gradient of flood frequency along which plant groups occur at predictable locations depending on their life history traits and recent hydrological conditions. A substantial proportion of species display ruderal life history traits including large, persistent soil seed banks and rapid life cycles which enable escape in time from the stresses associated with flooding and drought. These species, mostly comprising annual monocots and forbs, are widespread throughout the landscape and their presence in the extant vegetation is related primarily to the time since the last flood pulse event and the hydrological attributes of this. Perennial species, particularly shrubs, do not appear to rely similarly on the soil seed bank for recruitment and their distribution in the floodplain vegetation is likely to be determined more by their ability to tolerate either flooding or drought. Overall, this study demonstrates that flow, despite its variability, has an overriding influence on vegetation dynamics in the arid floodplain of the Cooper Creek. The spatial and temporal variability of flow maintains a heterogeneous mosaic of plant communities of differing composition and structure. Given this close relationship between flow and vegetation dynamics, anthropogenic alterations to flow are likely to result in changes to the vegetation including homogenisation of plant communities across the floodplain landscape and eventual loss of biodiversity.

Der Klimawandel ist auf regionaler Ebene nachweisbar. Zudem gehen Forschungsergebnisse davon aus, dass sich Ereignisse wie Überflutung und Starkregen regional differenziert zukünftig noch intensivieren werden. Bereits heute belegen Schadensmeldungen in der Region Dresden einen sich aus den klimatischen Veränderungen ergebenden Handlungsbedarf in Form von Anpassungsmaßnahmen auf Gebäudeebene. Deshalb sind die Hauptziele der vorliegenden Arbeit das Aufzeigen der Verletzbarkeit von Wohngebäuden und die Erarbeitung von Vorschlägen für entsprechende Ertüchtigungen. Als Datenbasis dient zum einen die baukonstruktive Analyse typischer Beispielgebäude der Region Dresden, welche gleichzeitig die wichtigsten Baualtersstufen abbilden. Dadurch können die in der Region hauptsächlich anzutreffenden baukonstruktiven Durchformungen, Nutzungen und Charakteristiken von Wohngebäuden abgedeckt werden. Dies dient als Grundlage zur Beurteilung der Verletzbarkeit und Anpassungsfähigkeit der wichtigsten Baukonstruktionen gegenüber den Einwirkungen Überflutung und Starkregen. Zum anderen dient als Datenbasis die Dokumentation, Analyse und Interpretation abgelaufener Schadensereignisse in Bezug auf Schadensbilder und Schadensmechanismen an Gebäuden und Baukonstruktionen. Innerhalb der Verletzbarkeitsanalyse gegenüber Überflutung führt die Beschreibung von Schadenstypen, Schadensbildern und Schadensmechanismen in die Erläuterung einer Methodik zur Abschätzung von Hochwasserschäden an Gebäuden. Diese wird in der Arbeit dazu verwendet, die spezifische Verletzbarkeit der einzelnen Beispielgebäude gegenüber der Einwirkung Überflutung mit Hilfe von Wasserstand-Schaden-Beziehungen zu ermitteln. Darauf aufbauend können nun Bereiche, welche aufgrund ihrer hohen Verletzbarkeit angepasst werden sollten, eingegrenzt werden. In der Folge werden beispielhaft bautechnisch mögliche Anpassungsmaßnahmen vorgestellt, am baukonstruktiven Detail gezeigt und ihre positiven Auswirkungen auf die Wasserstand-Schaden-Beziehungen beziehungsweise auf die Verringerung der Verletzbarkeit der Beispielgebäude dargestellt.

Thermal and chemical recovery processes are important EOR methods used often by the oil and gas industry to improve recovery of heavy oil and high viscous oil reservoirs. Knowledge of underlying mechanisms and their modeling in numerical simulation are crucial for a comprehensive study as well as for an evaluation of field treatment. EOS-compositional, thermal, and blackoil reservoir simulators can handle gas (or steam)/oil/water equilibrium for a compressible multiphase flow. Also, a few three-phase chemical flooding reservoir simulators that have been recently developed can model the oil/water/microemulsion equilibrium state. However, an accurate phase behavior and fluid flow formulations are absent in the literature for the thermal chemical processes to capture four-phase equilibrium. On the other hand, numerical simulation of such four-phase model with complex phase behavior in the equilibrium condition between coexisting phases (oil/water/microemulsion/gas or steam) is challenging. Inter-phase mass transfer between coexisting phases and adsorption of components on rock should properly be modeled at the different pressure and temperature to conserve volume balance (e.g. vaporization), mass balance (e.g. condensation), and energy balance (e.g. latent heat). Therefore, efforts to study and understand the performance of these EOR processes using numerical simulation treatments are quite necessary and of utmost importance in the petroleum industry. This research focuses on the development of a robust four-phase reservoir simulator with coupled phase behaviors and modeling of different mechanisms pertaining to thermal and chemical recovery methods. Development and implementation of a four-phase thermal-chemical reservoir simulator is quite important in the study as well as the evaluation of an individual or hybrid EOR methods. In this dissertation, a mathematical formulation of multi (pseudo) component, four-phase fluid flow in porous media is developed for mass conservation equation. Subsequently, a new volume balance equation is obtained for pressure of compressible real mixtures. Hence, the pressure equation is derived by extending a black oil model to a pseudo-compositional model for a wide range of components (water, oil, surfactant, polymer, anion, cation, alcohol, and gas). Mass balance equations are then solved for each component in order to compute volumetric concentrations. In this formulation, we consider interphase mass transfer between oil and gas (steam and water) as well as microemulsion and gas (microemulsion and steam). These formulations are derived at reservoir conditions. These new formulations are a set of coupled, nonlinear partial differential equations. The equations are approximated by finite difference methods implemented in a chemical flooding reservoir simulator (UTCHEM), which was a three-phase slightly compressible simulator, using an implicit pressure and an explicit concentration method. In our flow model, a comprehensive phase behavior is required for considering interphase mass transfer and phase tracking. Therefore, a four-phase behavior model is developed for gas (or steam)/ oil/water /microemulsion coexisting at equilibrium. This model represents coupling of the solution gas or steam table methods with Hand’s rule. Hand’s rule is used to capture the equilibrium between surfactant, oil, and water components as a function of salinity and concentrations for oil/water/microemulsion phases. Therefore, interphase mass transfer between gas/oil or steam/water in the presence of the microemulsion phase and the equilibrium between phases are calculated accurately. In this research, the conservation of energy equation is derived from the first law of thermodynamics based on a few assumptions and simplifications for a four-phase fluid flow model. This energy balance equation considers latent heat effect in solving for temperature due to phase change between water and steam. Accordingly, this equation is linearized and then a sequential implicit scheme is used for calculation of temperature. We also implemented the electrical Joule-heating process, where a heavy oil reservoir is heated in-situ by dissipation of electrical energy to reduce the viscosity of oil. In order to model the electrical Joule-heating in the presence of a four-phase fluid flow, Maxwell classical electromagnetism equations are used in this development. The equations are simplified and assumed for low frequency electric field to obtain the conservation of electrical current equation and the Ohm's law. The conservation of electrical current and the Ohm's law are implemented using a finite difference method in a four-phase chemical flooding reservoir simulator (UTCHEM). The Joule heating rate due to dissipation of electrical energy is calculated and added to the energy equation as a source term. Finally, we applied the developed model for solving different case studies. Our simulation results reveal that our models can accurately and successfully model the hybrid thermal chemical processes in comparison to existing models and simulators. / text

Hybrid gas/chemical Enhanced Oil Recovery (EOR) methods are such novel techniques to increase oil production and oil recovery efficiency. Gas flooding using carbon dioxide, nitrogen, flue gas, and enriched natural gas produce more oil from the reservoirs by channeling gas into previously by-passed areas. Surfactant flooding can recover trapped oil by reducing the interfacial tension between oil and water phases. Hybrid gas/chemical EOR methods benefit from using both chemical and gas flooding. In hybrid gas/chemical EOR processes, surfactant solution is injected with gas during low-tension-gas or foam flooding. Polymer solution can also be injected alternatively with gas to improve the gas volumetric sweep efficiency. Most fundamentally, wide applications of hybrid gas/chemical processes are limited due to uncertainties in reservoir characterization and heterogeneity, due to the lack of understanding of the process and consequently lack of a predictive reservoir simulator to mechanistically model the process. Without a reliable simulator, built on mechanisms determined in the laboratory, promising field candidates cannot be identified in advance nor can process performance be optimized. In this research, UTCHEM was modified to model four-phase water, oil, microemulsion, and gas phases to simulate and interpret chemical EOR processes including free and/or solution gas. We coupled the black-oil model for water/oil/gas equilibrium with microemulsion phase behavior model through a new approach. Four-phase fluid properties, relative permeability, and capillary pressure were developed and implemented. The mass conservation equation was solved for total volumetric concentration of each component at standard conditions and pressure equation was derived for both saturated and undersaturated PVT conditions. To model foam flow in porous media, comprehensive research was performed comparing capabilities and limitations of implicit texture (IT) and population-balance (PB) foam models. Dimensionless foam bubble density was defined in IT models to derive explicitly the foam-coalescence-rate function in these models. Results showed that each of the IT models examined was equivalent to the LE formulation of a population-balance model with a lamella-destruction function that increased abruptly in the vicinity of the limiting capillary pressure, as in current population-balance models. Foam models were incorporated in UTCHEM to model low-tension-gas and foam flow processes in laboratory and field scales. The modified UTCEM reservoir simulator was used to history match published low-tension-gas and foam coreflood experiments. The simulations were also extended to model and evaluate hybrid gas/chemical EOR methods in field scales. Simulation results indicated a well-designed low-tension-gas flooding has the potential to recover the trapped oil where foam provides mobility control during surfactant and surfactant-alkaline flooding in reservoirs with very low permeability. / text

The Participatory Irrigation Management approach was introduced into Cambodia in 2000, which was called the Participatory Irrigation Management and Development (PIMD). The goal of PIMD is to establish Farmer Water User Communities (FWUCs) to take over the management of irrigation schemes in their district in order to improve the performance of irrigation schemes and farmers’ livelihoods. The implementation of FWUCs has resulted in both failure and success. Several studies have identified factors that influence the failure of FWUCs, but little research has focused on their success. By employing a single embedded case study approach, this research selected the most successful scheme in Cambodia to identify factors that influenced the success of the FWUC in irrigation management. The findings of this research could provide concrete assistance to the government, donors, and non-governmental organisations in improving the performance of less successful FWUCs in Cambodia. The result of this research showed that the success of the O-treing FWUC was influenced by five internal and two external factors. The internal factors were: 1) the level of local participation, 2) the governance and management of the scheme, 3) the value of the benefits that flow from the irrigation scheme, 4) the quality of the irrigation infrastructure, and 5) the characteristics of the farmer members within the scheme. The external factors were: 1) the level of external support provided to the scheme, and 2) market access. The success of the FWUC required farmer participation and this participation was enhanced when farmers obtained benefits from it. This research also found that access to markets was critical to make the benefits that flowed from the irrigation scheme more profitable to farmers, leading to farmer participation. Similarly, it was also important to make sure that the irrigation infrastructure was of a high quality to ensure the delivery of an adequate and timely supply of water to farmers so that they could grow crops that provided them with the benefits. This required external support from the Ministry of Water Resources and Meteorology, NGOs, and local authorities to help rehabilitate the scheme. External support was also critical for enhancing the governance and management of the scheme through assistance with the formation process, provision of financial resources, capacity building, rule enforcement, and conflict resolution. The governance and management of the scheme, in particular the leadership capacity of the FWUC was another critical factor because it ensured the maintenance and development of the irrigation infrastructure, the timely and adequate supply of water to farmers, farmers’ trust and respect for leaders, and farmer participation. Finally, the success of the FWUC could not be viewed independently from farmer characteristics within the scheme. Farmers tended to participate in irrigation management when they had a history of self-organisation, when they were relatively homogenous, and when they were dependent upon farming for their livelihoods. This research suggests that the successful implementation of FWUCs requires a focus on the seven factors and the interactions that occur between these factors. Irrigation stakeholders such as the Ministry of Water Resources and Meteorology, donors, NGOs, local authorities, local leaders, and farmers should work together to enhance these factors in order to ensure the success of FWUCs.