The Lèze catchment (350 km², about 34,000 inhabitants) in south-west France is located in a hilly pre-mountainous area (Pyrenees), and is part of the larger Garonne catchment. The Lèze river has very marked seasonal variations in flow. A large irrigation dam in the upper part of the basin and 11 small dams along the river control the flow. The case study is located in regions that signed the Mission Charter of the EU Mission on Climate Adaptation.