To assess the extent to which it is possible to use satellite altimetric measurements over coastal areas, the SEASAT observatins made over the English Channel were intensively analyzed. Over this shallow water area, tides are very important (of the order of several meters), which introduces a large space and time variability of the sea surface elevations. A model of tidal prediction for the area studied was used to eliminate this variability. As meteorological effects can also introduce significant sea surface variations, a numerical storm surge model was also used. Thus it was possible to remove the main part of the sea surface time variations from the altimetric measurements. The analysis of six successive flights over the same ground track, during the Bermuda orbit, shows that the tidal and meteorological predictions are accurate and that the main deviations remaining in the altimetric signal result from large imprecision in the satellite ephemeris, of the order of several meters. From a detailed study of six other flights over the Channel, including a matching of the satellite tracking at the different crossing points, an altimetric geoid was established: as a first approximation it is in good agreement with the more recent geoids produced over this area; however, some significant differences can be seen which are of interest to geodesists.