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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
41

Wildlife and water: collective action and social capital of selected landowner associations in Texas

Wagner, Matthew Wayne 25 April 2007 (has links)
In Texas, landowner associations for the management of common-pool resources such as wildlife and groundwater have become increasingly popular. Successful management of white-tailed deer (Odocoileus virginianus) depends upon the collective decision-making of landowners. Likewise, aquifer reserves are a trans-boundary resource subject to the "rule of capture." Numerous factors may affect the success of common-pool associations, including property ownership and habitat characteristics, landowner demographics, and social capital. I used a mail questionnaire to explore the relationship between these factors and their effect on association activities and management practices for eight Wildlife Management Associations (WMAs) occurring within the Lower Post Oak Savannah (LPOS) and the Central Post Oak Savannah (CPOS). In addition, I compared responses of members of WMAs in CPOS to members of the Brazos Valley Water Alliance (BVWA), a groundwater association situated in the region. Compared to CPOS, members of WMAs within the LPOS belonged to much larger groups, were generally more recent landowners that met more often, raised more money using more funding methods, and tended to have longer association membership than CPOS landowners, yet they had lower social capital. CPOS landowners owned significantly more land and considered relaxation/leisure and hunting more important land uses than LPOS landowners. The smaller group size in CPOS may be the most important factor in building social capital. Intra-association trust was positively influenced by the longevity of property ownership, the number of association meetings, the percentage of males in the association, and other factors. Negative influences on trust included absentee ownership and Habitat Cover Index, which was a measure of the amount of wooded habitat present. In CPOS, members of the BVWA were part of a much larger, more heterogeneous, and more recently formed group than members of WMAs. They also placed greater importance on utilitarian aspects of their properties, as opposed to land stewardship for conservation as practiced by members of WMAs. If associations are kept small ( < 50) with more frequent meetings, greater social capital and information sharing may be achieved, which may lead to increased land stewardship practices. However, landowners may be motivated more by their shared values independent of any benefit from their association.
42

Citizen Action, Power Relations and Wetland Management in the Tampa Bay Urban Socio-ecosystem

Adjei, Cornelius Owusu 01 January 2012 (has links)
Wetlands are vital ecosystems that provide ecological, economic and social benefits to societies. In the Tampa Bay region in West Central Florida, a growing population has put immense pressure on wetlands. The situation has not gone unnoticed in the public domain with concerns raised about the need to formulate policies that would protect them. However, it has been difficult to ascertain the level of citizen involvement in the decision making process. This study aimed at investigating whether the perceptions and concerns of citizens drove them to influence local water policy. Questionnaires were used to collect data from residents living in close proximity to well fields situated in wetlands in Northwestern Hillsborough County. Results of the research showed that residents demonstrated a high degree of knowledge about water resources in the Tampa Bay region. Residents expressed concerns about groundwater pumping and development, and attributed them to changes in their environment. However, there was little engagement from residents with decision makers to address these concerns. This study therefore recommends that improved participatory mechanisms be created by local water agencies to incorporate valuable inputs from the public.
43

Stories like a River: The Character of Indian Water Rights and Authority in the Wind River and Klamath-Trinity Basins

Dillon, John F. January 2013 (has links)
The ability to decisively benefit from ample sources of freshwater represents a pivotal challenge for American Indian nations and their self-determination in the western United States. Climate change, population growth, and capitalist pressures continue to escalate demand for water in an already dry land. This project set out to listen and add practical perspective to the importance of water as reflected in various forms of stories in the context of American Indian reserved water rights. It explores dynamic confluences and divergences of worldviews that influence American Indian nations' relationships with water in the present sociopolitical context. The integral relationship between literatures, laws, and tribal sovereignty constructs this study's theoretical framework as it broadens scholarship on this connection to include the implications of water rights. This approach leads to a critical, or perhaps "literary critical," background for examining two major water rights struggles in the western United States; the first being court decisions on the Wind River Indian Reservation, home of the Eastern Shoshone and Northern Arapaho Tribes, and secondly, the Klamath-Trinity Basin, where four federally recognized tribes recently partook in water rights settlement negotiations. Litigation and negotiations over vital water are presently limited to the minefield of ambiguous Western narratives on the values and uses of Indian water rights. While each conflict has its unique circumstances and personalities, EuroAmerican stories of control and superiority continue to justify the exploitation of water and subjugation of Indigenous human rights. Alternative forums might make room for restorying and more sustainably managing water.
44

Traps and Transformations of Grenadian Water Management

Neff, Brian Phillip January 2013 (has links)
The adaptive cycle metaphor provides insight into how and why social-ecological systems change. Literature on 'resilience thinking' has built upon this foundation and further developed the concepts of resilience, adaptation, and transformation to describe social-ecological system behavior. The resilience-thinking literature also describes systems that do not change, even when such change is desirable, as being in a trapped state. However, relatively little research has explored why such systems are trapped and how to free them. This thesis is the product of doctoral research which resolves how to identify, evaluate, and free a system caught in a maladaptive system trap. The study setting is water management in Grenada, a small island developing state in the southeastern Caribbean. Four research questions guide this study: (1) To what extent is Grenadian water management in a trap?, (2) To what extent is Grenadian water management transformable?, (3) Do current and recent interventions effectively foster or utilize transformability?, and (4) Which interventions should be pursued to facilitate transformation of water management in Grenada?. The study is informed by literature on social-ecological systems and integrated water resources management. Methodologically, the study is an explanatory single-case study of water management in Grenada, conducted from 2012 to 2013. The study utilizes data from semi-structured interviews (n=19), a questionnaire (n=180), a document review (n>200), and observation. The general strategy was to evaluate attempts to transform Grenadian water management within the 3-phase transformation framework described in the resilience-thinking literature. 'Points of failure' in transformation are defined as the cause(s) of a trap, and interventions to relieve the points of failure are proposed. Results indicate Grenadian water management is in a rigidity trap, although it exhibits some capacity to transform. A key point of failure of attempts to transform the Grenadian water sector into an integrated and holistic management system has been an inability to seize windows of opportunity to pass key legislation. I conclude the primary cause for this failure is poor fit among the problem, as perceived by various stakeholders, the proposed solution prescribed by water sector reform proponents, and political reality. In addition, reform proponents focus on advocating for reform to water sector professionals and do little to broker passage of legislation politically. Finally, reform proponents also assume legislation will be effectively implemented, which is not certain. Contributions specific to the Grenadian setting include a post-mortem on why efforts to reform the water sector have failed, described above. Five recommendations are made for future interventions to foster transformation of Grenadian water management: (1) engage residents as part of a vision to create political pressure for proposed solutions, (2) frame the problem with substantial resident input and focus, (3) craft solutions which take advantage of political realities such as funding restrictions, (4) anticipate and prepare for crises, and (5) enlist one or more people or organizations to serve as brokers. Empirical contributions include support for the three-streams framework of seizing windows of opportunity as fundamental to explain transformation of social-ecological systems. The primary conceptual contribution is the development of resilience thinking to illuminate ways to free trapped systems. I begin by providing a nomenclature to quantify and describe traps, which includes the type of trap, the degree of persistence and undesirability of the trap, and recent changes in these properties. Then, I develop a framework to assess transformability of a given system based on the existing 3-phase framework of transformation. When applied empirically, this framework illuminates points of failure of transformation, which I define as the cause of a given trap. Once identified, specific strategies can be devised to foster transformation and to break free of a trap.
45

Traps and Transformations of Grenadian Water Management

Neff, Brian Phillip January 2013 (has links)
The adaptive cycle metaphor provides insight into how and why social-ecological systems change. Literature on 'resilience thinking' has built upon this foundation and further developed the concepts of resilience, adaptation, and transformation to describe social-ecological system behavior. The resilience-thinking literature also describes systems that do not change, even when such change is desirable, as being in a trapped state. However, relatively little research has explored why such systems are trapped and how to free them. This thesis is the product of doctoral research which resolves how to identify, evaluate, and free a system caught in a maladaptive system trap. The study setting is water management in Grenada, a small island developing state in the southeastern Caribbean. Four research questions guide this study: (1) To what extent is Grenadian water management in a trap?, (2) To what extent is Grenadian water management transformable?, (3) Do current and recent interventions effectively foster or utilize transformability?, and (4) Which interventions should be pursued to facilitate transformation of water management in Grenada?. The study is informed by literature on social-ecological systems and integrated water resources management. Methodologically, the study is an explanatory single-case study of water management in Grenada, conducted from 2012 to 2013. The study utilizes data from semi-structured interviews (n=19), a questionnaire (n=180), a document review (n>200), and observation. The general strategy was to evaluate attempts to transform Grenadian water management within the 3-phase transformation framework described in the resilience-thinking literature. 'Points of failure' in transformation are defined as the cause(s) of a trap, and interventions to relieve the points of failure are proposed. Results indicate Grenadian water management is in a rigidity trap, although it exhibits some capacity to transform. A key point of failure of attempts to transform the Grenadian water sector into an integrated and holistic management system has been an inability to seize windows of opportunity to pass key legislation. I conclude the primary cause for this failure is poor fit among the problem, as perceived by various stakeholders, the proposed solution prescribed by water sector reform proponents, and political reality. In addition, reform proponents focus on advocating for reform to water sector professionals and do little to broker passage of legislation politically. Finally, reform proponents also assume legislation will be effectively implemented, which is not certain. Contributions specific to the Grenadian setting include a post-mortem on why efforts to reform the water sector have failed, described above. Five recommendations are made for future interventions to foster transformation of Grenadian water management: (1) engage residents as part of a vision to create political pressure for proposed solutions, (2) frame the problem with substantial resident input and focus, (3) craft solutions which take advantage of political realities such as funding restrictions, (4) anticipate and prepare for crises, and (5) enlist one or more people or organizations to serve as brokers. Empirical contributions include support for the three-streams framework of seizing windows of opportunity as fundamental to explain transformation of social-ecological systems. The primary conceptual contribution is the development of resilience thinking to illuminate ways to free trapped systems. I begin by providing a nomenclature to quantify and describe traps, which includes the type of trap, the degree of persistence and undesirability of the trap, and recent changes in these properties. Then, I develop a framework to assess transformability of a given system based on the existing 3-phase framework of transformation. When applied empirically, this framework illuminates points of failure of transformation, which I define as the cause of a given trap. Once identified, specific strategies can be devised to foster transformation and to break free of a trap.
46

Making space for environmental problem solving: a study of the role of "place" in boundary choices using Georgia's statewide planning process as a case

Hirsch, Paul Devin 17 November 2008 (has links)
In this dissertation, the concept of "problem bounding," argued by Bryan Norton and colleagues to be an important but understudied aspect of environmental problem solving, is operationalized and empirically investigated. The empirical part of the work involves participant observation and survey research on how diverse individuals – all of whom were invited by a state agency to advise the development of an institutional framework for statewide water planning – engaged in problem bounding both conceptually and in their choice of a spatial structure for ongoing water management. My particular focus is on the multiple ways in which the "place" an individual views the problem from shapes the way they engage in problem bounding. Although more research is needed and there are significant limitations to the data, my findings indicate that place – particularly in terms of location on an upstream/downstream continuum and rural/urban self-identification – does play a role in problem bounding. The dissertation concludes with a review and discussion of the major findings, and implications for the development of institutional frameworks that are both responsive to ecological dynamics and representative of the relevant public(s).
47

Essays on water economics / Essais sur l'économie de l'eau

Pontoni, Federico 08 May 2014 (has links)
La thèse est structurée autour de quatre articles. Le premier article - What determines efficiency? An analysis of the Italian water sector – offre une évaluation d’efficience du plus grand échantillon d’entreprises italiennes dans le secteur de l’eau qui ait jamais été rassemblé. Cela sur un horizon temporel de quatre ans. Le deuxième article – Hydropower rent in Northern Italy: economic and environmental concerns in the renewal procedure – a deux objectifs: le premier est d’estimer la rente de l’hydroélectricité en Italie, ce qui n’a jamais été intenté auparavant ; le seconde est d’analyser le trade-off entre l’appropriation de la rente et les améliorations environnementales. Le troisième article – Estimating a performance-based environmental fee for hydropower production: a choice experiment approach – développe une redevance basée sur la performance environnementale à mesure non seulement d’internaliser les coûts environnementaux que l’hydroélectricité détermine, mais aussi d'inciter les producteurs à aller au delà de la régulation environnementale existante : de cette façon, ils payent moins. Enfin, le quatrième article – Cheaper electricity or a better river? Estimating fluvial ecosystem value in Southern France – applique la méthodologie CE à l’étude du trade-off potentiel entre revenue-sharing et améliorations environnementales dans la Vallée d’Aspe (Pyrénées français), où plus de 100 MW de capacité hydroélectrique sont installés. / The thesis is structured as a collection of four papers and it is ideally divided into two parts: the first one, composed of just one paper, is an efficiency analysis of the Italian integrated water sector; the second part, made of the other three papers, is thematic and studies hydropower production in terms of rent generation and environmental impacts.The first paper – What determines efficiency? An analysis of the Italian water sector – offers an original evaluation of the efficiency of the biggest sample ever gathered of Italian water companies over a period of four years.The first paper of the thematic part – Hydropower rent in Northern Italy: economic and environmental concerns in the renewal procedure – has two objectives: the first one is to estimate the hydropower rent in Italy, which has never been done before; the second one is to investigate the trade-off between rent seizing and environmental improvements.The second thematic paper – Estimating a performance-based environmental fee for hydropower production: a choice experiment approach – develops a performance-based environmental fee able not only to internalize the environmental costs that hydropower causes, but also to stimulate producers to outperform existing environmental regulation: the more they outperform, the less they pay.Finally, the third thematic paper – Cheaper electricity or a better river? Estimating fluvial ecosystem value in Southern France – applies the DCE approach to study the potential trade-off between revenue-sharing and environmental improvements in the Aspe valley, located in the French Pyrenees, where more than 100 MW of hydropower capacity are installed.
48

ANÁLISE DOS INSTRUMENTOS DE GESTÃO DE RECURSOS HÍDRICOS COM ÊNFASE NAS AÇÕES DO COMITÊ DE BACIA DO RIO SANTA MARIA, RS / ANALYSIS OF INSTRUMENTS OF WATER RESOURCES MANAGEMENT: ACTIONS OF THE SANTA MARIA RIVER WATERSHED MANAGEMENT COMMITTEE

Dulac, Vinicius Ferreira 27 February 2013 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The Santa Maria watershed is located in southwestern of Rio Grande do Sul State and has area of 15,740 km ². Irrigation by means of agriculture is the largest user of water. The main goal of this research was to analyze strategies of water management based on discourses of social agents of the Committee of Management of Santa Maria River Watershed (CMSMW) from 2008 to 2012 - which means two biennium of management. It was proposed to analyze discourse changes from the minutes of meetings of the CMSMW. To accomplish these aims, firstly it was categorized social agents speeches - which are called ideas - to determine a sample unit of analyses, about water management instruments (resulting in N = 433). After that it was applied the concept mapping method, which was used to organize and to articulate the visual representation of networks of ideas, by using multivariate statistics techniques. Lately, it was developed a database and were included in activities that are part of the internal dynamics of the CMSMW. In total, 45 organizations had ideas recorded in minutes in the period of analysis. The structure of the conceptual map showed that there is a preponderance of the discussions and effective actions of the Committee related to the registration of users for the grant of water use Another aspect is that the uncertainty of supply due to lack of monitoring of discharges is a critical factor in the basin, resulting in a wide trading, but without effective referrals. There was a 13% increase in ideas classified as Water Resources Management Instruments from one biennium to another, and it was shown an improvement in the quality of the minutes. Also, there was a preponderance and increasing qualification of such matters as "system information user and granting of grants" and "strategies for managing supply" with an emphasis on self-management. Despite the large amount of ideas, the method assisted in the analysis of preponderant themes, inter-relationships, decision-making and effectiveness of actions. It is expected that the results of the analysis may assist the Committee in self-assessment of its actions and the direction of its management. / A bacia hidrográfica do rio Santa Maria, localiza-se na fronteira sudoeste do RS e tem uma área de 15.740 km². A agricultura irrigada é a atividade que possui a maior demanda de água na bacia. O objetivo geral desta pesquisa é analisar as estratégias de gestão dos recursos hídricos, com base nos discursos dos agentes sociais do Comitê de Gerenciamento da Bacia Hidrográfica do Rio Santa Maria (CBHSM), entre os anos de 2008 e 2012 o que engloba dois biênios de gestão. Propõe-se, também, detectar possíveis mudanças e ou permanências nas ideias que fizeram parte das reuniões do CBHSM. Para efetivar tais propósitos, primeiramente categorizaram-se as ideias dispostas na narrativa das atas, de modo a determinar uma unidade amostral no âmbito dos instrumentos de gestão dos recursos hídricos (resultando em N=433). Em seguida, aplicou-se o método de Mapeamento Conceitual o qual foi utilizado para organizar e articular a representação visual de redes de ideias a partir de técnicas de estatística multivariada. Para operacionalizar a análise foi desenvolvido um banco de dados relacional para inserir as atividades que fazem parte da dinâmica interna do Comitê. No total, 45 entidades tiveram ideias registradas em ata no período de análise. A estrutura do mapa conceitual mostrou que há uma relação direta entre a preponderância das discussões e ações efetivas do Comitê junto ao cadastramento de usuários para outorgas, e, serem estes os processos mais avançados de implantação na bacia. Outro aspecto é que a falta de monitoramento de vazões é um fator crítico na bacia, resultando em uma ampla negociação, porém sem encaminhamentos efetivos. Houve o incremento de 13% nas ideias da amostra analisada entre um biênio de gestão e outro, bem como uma melhora na qualidade da redação das atas. Também, verificou-se a preponderância de assuntos tais como sistema de cadastro de usuários e concessão de outorgas e estratégias para a administração da oferta com ênfase na autogestão. Apesar da alta quantidade de variáveis analíticas - as ideias, o método utilizado auxiliou a análise de temas preponderantes, de inter-relacionamentos, tomada de decisões e a efetividade das ações. Espera-se que os resultados da análise possam auxiliar o Comitê e os demais órgãos integrantes do Sistema de Recursos Hídricos na autoavaliação de suas ações e no direcionamento de sua gestão.
49

Advancing Water Security and Environmental Sustainability Through Evaluation of Water Use From the Field to State-Wide Scale

Sangha, Laljeet Singh 17 January 2023 (has links)
The United States (US) has experienced a surge in water shortages and droughts in recent times. Water shortages can result from population growth, climate change, inadequate water management policies, and the improper use of available technologies. The existing data and research on water use associated with water management policy structures are limited. Many states in the US follow strict regulations on water discharge into streams to enforce water quality standards; however, water withdrawal restrictions from streams are limited and inadequate in terms of water management at times of low flow. In states such as Virginia (VA), the Virginia Department of Environmental Quality (VDEQ) requires a Virginia Water Protection (VWP) permit for all water withdrawals from VA's surface waters. However, under certain provisions of VWP regulations, users are exempted from having a permit. Such permit exemptions exist in many states and present a severe challenge to water supply management. Chapter 2 compares the impact of permit exemptions on surface water availability and drought flows and compares these impacts to the relatively well-studied risks presented by dry climate change and demand growth in Virginia (VA). It was observed that in some regions, the impacts under the exempt user scenario were higher than those under the dry climate change scenario. In addition, water supply managers and government agencies use user-reported water withdrawal data to develop water management programs. Irrigated agriculture is the largest source of water consumption in the US. However, water-reporting regulations exempt users from withdrawing water for irrigation under a certain threshold. Moreover, as water is not metered, users often do not report their irrigation water use, resulting in considerable uncertainty about the impacts of irrigation withdrawals, which could potentially impact other water users, lead to water shortages or conflicts, and negatively impact stream ecology. Chapter 3 focuses on developing a novel methodology for quantifying unreported irrigation water withdrawals using publicly available USDA-Census and USDA-IWMS datasets. This method was used to evaluate the unreported water withdrawals in the VA. Finally, water use practices at the field level intersect with other environmental issues at a larger scale. For example, irrigation practices can influence nutrient uptake and transport at the field level. Insufficient water for irrigation, especially during critical growth stages, results in yield and economic losses and reduces agricultural productivity. However, excessive irrigation can lead to wasted water and energy as well as runoff and leaching of nutrients and agricultural chemicals. Therefore, the adoption of technological advancements at the field scale can reduce the amount of water needed to fulfill the needs while mitigating any nutrient impacts on the soil due to the excessive use of water. This is highly important when fertilizer prices are always high. Chapter 4 focuses on quantifying the impact of the use of short-term weather forecast data in irrigation scheduling on nutrient and water use efficiency in humid climates: experimental results for corn and cotton. It was found that irrigation scheduling using short-term weather forecast data is helpful for improving the nutrient and water use efficiency of corn. For cotton, nutrient and water use efficiency are highly influenced by irrigation and precipitation with respect to the growth stage. / Doctor of Philosophy / Water shortages in the US have increased in recent times owing to climate change. Water demand is expected to increase in the future due to population growth and economic development in certain regions. Water supply planning is significantly influenced by water policy regulations. Water withdrawal regulations mandate a water withdrawal permit for making withdrawals in many states across the US. However, due to provisions in the same water regulations, certain users are exempt from taking a water withdrawal permit. One example of such users is grandfathered users who had a water withdrawal permit before July 1, 1989, in Virginia. Such exemptions are a severe challenge to the management of water supply, as exempt withdrawal amounts are generally high. We studied the impacts of these exempt users on VA's water resources of VA and compared them with the impacts of dry climate change and 2040 demand growth in Chapter 2. The results indicate that the impact of exempt users is higher than that of climate change in some regions across VA. Additionally, water-reporting regulations require users to report irrigation water withdrawals. However, users below the reporting threshold were excluded from reporting. Some users might underreport or do not comply with the water withdrawal regulations. These user-reported data are often used in developing water management plans, which may become ineffective owing to incomplete water use data. Chapter 3 focuses on the development of a data-based approach for quantifying unreported irrigation water withdrawals. This method would be transferable to any other state across the US. We compared the estimated irrigation withdrawals with reported irrigation withdrawals across the VA and generated unreported withdrawals at the county level in the VA. Finally, at the field level, irrigation can highly influence the nutrient uptake of plants. Excess irrigation may result in the removal of nutrients below the roots of the plant or may be removed by surface runoff, making it unavailable for plant uptake. Along with the economic impacts of unused fertilizer and loss in yield, unused nutrients may impact the environment and water bodies. Chapter 4 focuses on the impact of short-term weather forecast data on the irrigation scheduling of corn and cotton in humid climates. We found that weather-informed irrigation is helpful in increasing the nutrient and water use efficiency of corn. For cotton, the results were highly affected by precipitation and irrigation with respect to the growth stage of cotton.
50

Adaptation de l'agriculture aux politiques de gestion de l'eau et aux changements globaux : l'apport des modèles de programmation mathématique / Agricultures' adaptation to water management policies and global change : the interest of economic programming models

Graveline, Nina 09 December 2013 (has links)
Cette thèse développe et discute différentes approches micro-économiques de modélisation de l’agriculture pour représenter l’effet de changements globaux et de politiques de gestion de l’eau sur l’adaptation de l’agriculture et sur les ressources en eau. Après un chapitre de synthèse et une revue de la littérature, quatre essais sont présentés. Le premier essai décrit la représentation du comportement de dix exploitations agricoles en Alsace et en Bade (Allemagne) à partir de modèles de programmation linéaire qui intègrent la prise en compte du risque. Après extrapolation, les résultats de simulation sont couplés à une chaîne de modèle plante-sol et de transfert hydrogéologique afin d’estimer la concentration future en nitrate dans l’aquifère du Rhin supérieur. Les simulations des trois scénarios de changements - tendanciel, libéral et interventionniste - suggèrent que les concentrations en nitrates baissent dans les trois cas par rapport à la référence. Le second essai explore l’effet de l’incertitude de changements globaux sur les ressources en eau par des simulations Monte Carlo pour le modèle alsacien (premier essai) et un modèle de demande en eau agricole (Sud-Ouest). Plusieurs niveaux de dépendance entre les paramètres incertains sont caractérisés. L’analyse des résultats montre que les objectifs environnementaux peuvent être déterminés avec suffisamment de précision malgré l’incertitude forte. Le troisième essai développe un modèle agricole régional de programmation mathématique positive avec élasticité de substitution constante entre l’eau et la terre afin d’explorer comment l’agriculture, partiellement irriguée, de Beauce s’adapte à une baisse de la disponibilité en eau. La réponse du rendement à l’eau est calibrée à partir d’information agronomique. Les adaptations à la baisse de disponibilité en eau sont distinguées selon qu’elles correspondent à des baisses de dose d’eau d’irrigation ou de changement de culture. Environ 20% de la réduction est due à la baisse des doses d’eau (marge intensive). Le dernier essai présente un modèle hydro-économique “holistic” de l’agriculture et de l’aquifère de Beauce afin d’évaluer plusieurs politiques de gestion quantitatives de l’eau ainsi que d’évaluer le cas où l’accès à la ressource n’est plus régulé. Des simulations dynamiques sont réalisées à l’horizon 2040 en tenant compte de l’incertitude liée au changement climatique. La politique actuelle de quotas annualisés semble être plus coût-efficace que les autrespolitiques testées (taxes, transferts etc.). / This thesis develops and discusses agricultural-supply modeling approaches for representing the adaptation of farming to global changes and water policies: their effects on agricultural economics and water resources comprise critical information for decision makers. After a summary and a review chapter, four essays are presented. The first essay describes a representation of the behavior of ten typical farms using a risk linear programming model connected to a plant-soil-hydrodynamic model chain, to assess the future level of nitrate contamination in the upper Rhine valley aquifer. The baseline, liberal, and interventionist scenarios for 2015 all result in lower nitrate concentrations. The second essay explores the effects of the economic uncertainty of global changes by means of a Monte Carlo approach distinguishing various levels of dependence on uncertain parameters. Analyses for a nitrate-oriented and a water-use model (in Alsace and southwestern France) show that the environmental objectives can be targeted withsufficient confidence. The third essay develops a flexible specification for positive mathematical programming - constant elasticity of substitution with decreasing returns - to explore how irrigated farming adapts to increased water scarcity in Beauce, France. The possibility of adjusting the application of water per hectare accounts for about 20% of the response. The last essay presents the development of a holistic hydro-economic model of Beauce’s agriculture and aquifer under climate-change uncertainty, so as to evaluate various water policies, as well as the open-access case, up to the year 2040. The results show that the baseline policy is more cost-effective than the other instruments tested (tax, transfer,etc.).

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