Résumé
In the Cévennes, in summer, water resources are rare. The gap between these resources and population needs generates local difficulties. Climate change (possible aridification…) and the evolution of lifestyles (increase in consumption, water for leisure activities…) may increase the problems in the future. Except for inter-basin transfers, the solution can only be found in a more appropriate exploitation and sharing of available water at each point of the river system. The HydroPop program is based on the necessity of a fair sharing of the resource assuming a knowledge of the hydrologic phenomenon and supported on the population attachment of the population to their natural environment. The idea of sharing must therefore be based on an attachment to a shared environment. This implies a responsible collective attitude, underpinned by a participatory and deliberative local democracy, that is to say, popular. To this end, the means to inform the interested parties must be put in place. The first requirement is therefore to better assess the water resource availability in summer. To this end, we carry out measurements on ten sections of the hydrographic network of the Gardons d'Anduze and Alès. To be performative, these measurements require a processing chain almost in real time before informing the population, on one hand through drought gravity scales (Gravisec four-level scales) put at three points, and on the other hand by weekly media releases. The HydroPop project also aims at investigating the local water culture and the expectations of the populations living in the Cévennes. This phase of knowledge gathering may lead to the recruitment of occasional volunteer observers who will complement the collection of information, which should ultimately take place on a dedicated website.