MAREL: automated measurement network for the coastal environment

The MAREL programme attempts to develop automated monitoring stations for classical sea water analysis, able to work autonomously in coastal areas. A land-based station automatically receives and stores data, keeps them available for the users via the Internet and may also receive alarm messages from monitoring stations. Water samples are pumped from different levels in the sea water column and are analysed by sensors located in a measuring cell on the floating structure. This allows a continuous cleaning of the sensors to secure measurement quality and the injection of chlorinated ions in the hydraulic circuit to avoid biofouling. The system status can be known at any time and, if necessary, in some cases, can be repaired by remote operating maintenance, saving data and saving an onerous on-site intervention. The measuring system can be adapted to different conditions of the coastal environment, for example estuary environment with turbid waters and very fast variations of the parameters. It will be able to evolve by replacing or adding new modules for new parameter analysis. The data transmission system is also standardized, using the telephone and GSM network, VHF or satellites if necessary. Sensors used for the Seine Bay MAREL programme analyse water temperature, salinity, turbidity, pH, amount of dissolved oxygen, nitrates and chlorophyll in the sea water, and added parameters such as hydrological (current, wave) and meteorological (air temperature and pressure, wind) ones