Konstruktionen av kvantitativ vattenförvaltning i Frankrike studerad genom Marais Poitevin : En analys av den socio-politiska historien bakom substitutionsreservoarprojekt

This thesis investigates the socio-political construction of quantitative water management in France through the hydrosocial trajectory of the Marais Poitevin, shaped by the implementation of contested substitution reservoirs. Using a political ecology of the State framework, the thesis examines how state-led governance has shaped—and been shaped by—the hydrosocial trajectory of this wetland, following the State’s attempts in the early 2000s to correct the former regime. This period came after the European condemnation for insufficient protection of the natural park and amid growing pressures from irrigation development. By analyzing the deployment of governance instruments and the uneven outcomes of reservoir projects across Vendée, Deux-Sèvres, and Charente-Maritime, alongside the parallel construction of national water policy, the study examines how local and national processes intersect. It highlights the co-construction of a territory with unequal impacts in adapting to new hydroclimatic conditions and to the state’s quantitative water management policies. Drawing on extensive documentary analysis and semi-structured interviews with local actors, the research traces the evolution of water governance and the associated hydrosocial cycles. It demonstrates how the state’s negotiated compromise with productivist agriculture—regulating summer water abstractions in exchange for reservoir development—consolidated a supply-oriented model while marginalizing alternative problem framings. The Marais Poitevin emerged as a nodal site where local controversies escalated into national debates, mediated by brokers who relayed territorial interests to policy arenas. However, these processes remained constrained by neo-corporatist dynamics favoring agricultural actors, resulting in national procedural frameworks that formalized consultation without challenging the expansionist logic of reservoir storage. The interaction between local and national dynamics produced divergent hydrosocial trajectories across departments, shaped by variations in project proponents, economic viability, and opposition coalitions. While reservoir projects in Vendée advanced due to the convergence of these factors, those in Deux-Sèvres and Charente-Maritime encountered prolonged blockages, revealing the fragility of stateenvironmental compromise. This in-between situation —where projects are neither fully implemented nor abandoned—has intensified hydroclimatic vulnerability and regulatory instability, undermining the territory’s capacity for structural adaptation. Ultimately, the thesis argues that the state’s reliance on and support for controversial technical solutions, such as substitution reservoirs, has deepened socioenvironmental conflicts, leaving the region in a prolonged crisis of hydrosocial governance.