Suspended Particulate Matter (SPM) surface concentration maps in the Belgian/Dutch coastal zone are retrieved from SeaWiFS images and are corrected using in situ measurements to obtain depth-averaged SPM concentration maps. A spatial correlation analysis of the derived maps shows that the area could be divided into three subregions where the correlations between the SPM concentrations are higher than 70\%. Examination of in situ SPM concentration measurements reveals that during about 1/3 of the tidal cycle the SPM concentration is significantly higher than during the rest of the cycle. Strong vertical gradients are sometimes observed during periods with increased SPM concentration. A satellite image taken during such a period would underestimate the depth-averaged SPM concentration. Images taken during other periods better represents (except for some small corrections) the averaged SPM concentration. The methodology for obtaining the depth-averaged SPM concentration maps from surface SPM distributions derived from SeaWiFS images is positive but can be further improved. © 2007 Elsevier B.V. All rights reserved.