Strongly committed to the fight against the pollution of bathing water, which is a major challenge in terms of ecological and tourism economics, the Agglomeration Coast Basque Adour and its 3 coastal cities are launching a joint R&D project in order to have innovative operational tools shared to assist decision-making for the active management of their beaches. Carried out over a period of 5 years, the project will lead to the realisation of 3 numerical models for the prediction of bathing water quality. It will optimise the active management of the Agglomeration beaches, reduce the bacteriological contamination factors of bathing water, and better inform and protect ocean users from bacteriological pollution.