La thèse aborde la problématique des usages de l'eau dans un archipel ouest-africain semi-aride, pauvre, vulnérable, où la question des ressources hydriques a toujours posé de graves problèmes, que cinq siècles de colonisation n'ont pas résolu. Dans un monde ouvert, interdépendant, où les questions de durabilité environnementale, de production agricole, de sécurité alimentaire et de lutte contre la pauvreté et pour le développement sont des enjeux majeurs pour la planète et ses habitants, la gestion intégrée des ressources en eau (GIRE) constitue une solution intéressante pour une économie cap-verdienne de l'eau répondant à ces défis.L'objectif de la thèse est de contribuer à la mise en œuvre de la GIRE sur le territoire de la République du Cap-Vert. Elle s'interroge sur le « modèle transféré » des barrages hydrauliques, avec l'exemple de celui de Poilão, dans la Ribeira Seca de l'île de Santiago, premier barrage construit au Cap-Vert, avec l'aide de la coopération chinoise. Elle examine le rôle et les effets de l'irrigation, les impacts de sa réalisation sur l'environnement local, ainsi que les problèmes socio-économiques entraînés par l'usage de l'eau dans le bassin versant de la Ribeira Seca. La thèse s'interroge sur la question de la gouvernance juridique, réglementaire et institutionnelle de l'eau au Cap-Vert, avec des comparaisons internationales. Enfin, elle propose un modèle de gestion de l'eau inspiré de l'approche GIRE. / This thesis deals with the problem of water use in a poor, vulnerable, semi-arid West African archipelago where the issue of water resources has always posed major problems, problems which five centuries of colonization were unable to solve. In an open, interdependent world in which issues of environmental sustainability, agricultural production, food security and the fight against poverty and in favor of development are major challenges for the planet and its inhabitants, integrated water resources management (IWRM) constitutes an interesting solution for an economy of water that responds to these difficulties in the country.The objective of the thesis is to contribute to the implementation of integral water resource management in the territory of the Republic of Cabo Verde. It questions the “adopted model” of hydraulic dams, with the example of the Polião Dam in Ribeira Seca valley, on the island of Santiago, the first dam built in Cabo Verde, with the help of the People’s Republic of China. It examines the role and effects of irrigation, the impacts of engaging therein on the local environment, and the socio-economic problems caused by water usage in the Ribeira Seca watershed.The thesis also uses international comparisons to raise questions related to the legal, regulatory and institutional governance of water in Cabo Verde. Finally, it proposes a water management model inspired by the Integrated Water Resources Management approach. / A presente tese aborda a questão do uso da água num arquipélago Oeste Africano semiárido, pobre, vulnerável, onde a questão dos recursos hídricos sempre levantou problemas graves, que cinco séculos de colonização não conseguiram resolver. Num mundo interdependente e aberto, onde as questões de sustentabilidade ambiental, a produção agrícola, a segurança alimentar e a luta contra a pobreza e pelo desenvolvimento são as questões fundamentais para (a preservação) do planeta e seus habitantes, a gestão integrada dos recursos hídricos (GIRH) é uma solução interessante para uma economia cabo-verdiana da água que responda a estes desafios.O objetivo desta tese é o de contribuir para a implementação da GIRH no território da República de Cabo Verde. A tese questiona sobre o "modelo transferido " de barragens, como por exemplo o da Barragem de Poilão na Ribeira Seca, na ilha de Santiago, a primeira barragem construída em Cabo Verde, com a ajuda da Cooperação chinesa. A tese examina o papel e os efeitos da irrigação, o impacto da sua implementação no ambiente local, assim como os problemas socioeconómicos causados pelo uso da água na bacia hidrográfica de Ribeira Seca.A tese interroga-se sobre a questão da governança jurídica, regulamentar e institucional da água em Cabo Verde, usando o direito comparado internacional. Finalmente, a tese oferece um modelo de gestão da água, com base na abordagem GIRH.

This interdisciplinary thesis studies the diverse multi-stakeholder networks that are constitutive of contemporary water governance. It examines collaborative governance networks from a relational perspective in two case study watersheds in Tanzania and Ethiopia. Collaborative and networked governance approaches are increasingly promoted to address complex water challenges, but relatively little is known about how the everyday collaborative relationships (i.e. collaboration practices) among the multiple actors involved in the development, management and use of water, shape contemporary water governance processes. In this thesis, I advance, based on intensive fieldwork data collection, a conceptual and methodological framework for studying collaboration networks pertaining to watershed management. I examine local collaborative governance networks in two watersheds, in Ethiopia and Tanzania, from a relational perspective, using complementary qualitative and quantitative social network research methods. The thesis explores the opportunities and limitations of such collaborative governance networks in their concrete functioning, thereby contributing to a more context-sensitive, and nuanced, understanding of the role of governance networks and collaborative governance approaches in the management of water and related resources.