LOIEAU : a software for the regional estimation of water resources - Application to the determination of reference flows in the French Mediterranean region

Abstract

Initialized by the Corsica, Languedoc-Roussillon and Provence-Alpes-Côte-d'Azur DIREN, a thorough gathering of all available hydrometeorological data has been undertaken in the French Mediterranean region. The goal of this task is to acquire a better knowledge of reference flows (module and minimum monthly flow for a five-year frequency) everywhere in the hydrographic network of this region. A modelling approach of rain water runoffs, with a monthly step, has been selected. The GR2M model has proven to be very well adapted. Its accuracy is excellent for the module estimation. Even though the low water flows are estimated with some dispersion, the overall results remain very good. Moreover, the two model parameters describe accurately the rivers' hydrological status, which has allowed us to extend the results to the whole region. This methodology as well as the necessary databases have been included into the LOIEAU software. The fact that it has been developed under a WINDOW configuration makes it user-friendly. With the LOIEAU software, the DIREN now have a tool that allows them to not only estimate the reference flows, but also to tackle all problems related to the water supply and to its seasonal and interannual variability, everywhere in the hydrographic network of the French Mediterranean area.