Résumé
We study the properties of a pricing rule for irrigation water with two variables: the volume consumed by the farmer and the volume he/she reserves before the plantation. With a simple deterministic model, we show how this pricing rule allows the Water User Association manager to anticipate any possible usage conflict thanks to farmer information revelation, to guarantee his/her association budget equilibrium. We show too how farmers are incited to restrain their use of water. Moreover this pricing method is fair (all farmers are equally treated), flexible through the possible change of the value of the parameters, and moreover simple and easily understandable (when for example translated in a double entry table). Therefore, it compares favorably to other classical water pricing methods.