ASPB and ACBA wish to undertake studies to make bacteriological measurements and forecasts of real-time water quality carried out on bathing areas reliable in order to ensure the highest quality of water. It is therefore necessary to better understand the survival times of bacteria, which is dependent on various natural parameters: salinity, light, temperature... to isolate their respective influences on bacterial mortality. The UR Bidea project, which emanates from the work of GIS Littoral Basque, aims to provide scientific answers to these problems. This new knowledge will be implemented within modelling tools in order to secure the choices of elected representatives.