||The Normandy hydrological coastal monitoring network is a project running for almost 10 years with two main goals: 1) to assess the quality and the potential eutrophication status of coastal water masses, and 2) to help implementing the Water Framework Directive (WFD) surveillance programme in the region, regarding the biological (here phytoplankton) and physico-chemical quality elements.At most, 30 stations were sampled for chlorophyll-a, phytoplankton, physico-chemical parameters (temperature, salinity, and dissolved oxygen) and nutrients data from 2000 to 2009 on 18 coastal and 4 transitional water masses. Therefore the representativeness of sampling stations relative to the objectives aimed, and the comparability of methods of analysis were addressed in order to optimise the cost and effectiveness of the programme.These hydrological and phytoplankton data showed a clear contrast between oligotrophic-type systems in the western and eastern side of the Cotentin peninsula, and heterotrophic-type systems in the bay of Seine influenced by nutrients inputs from 4 water-basins including the Seine (70.000 sq km).The EU-validated indicators for biomass (i.e. chlorophyll-a concentration), for phytoplankton abundance (i.e. blooms of more than 100.000 cells per litre for species ≥ 20 µm), and dissolved oxygen at the bottom were calculated. The results were discussed for their relevance to evaluate heath status of Normandy near-shore waters. Finally, the implementation of new indicators for phytoplankton composition and nutrients concentration in the region was studied.