Measure of the color of beach nourishment sands: A case study from the Belgium coast

The aesthetical perception of a beach as a recreational place is closely linked to the sand color. This is one of the most perceptible characteristics of a beach. Sand color can be altered after a nourishment work. This type of works is becoming more and more popular since they represent a good tool for preserving beaches from erosion. However, only little (or none) attention has been paid to sand color during nourishment works. Colors of the sands from the Belgian coast were determined in the Cielab space, together with their granulometry and composition. Color coordinates range between 50 and 60 for L*, 0.5 to 4.0 for a*, and 10.5 to 16.5 for b*. The composition shows a dominant quartz fraction, followed by shell fragments and finally rock fragments. Granulometry is rather homogeneous, being the grain distribution for the east part of the coast narrower than for the west coast. This work describes the methodology for performing colorimetric analysis in sand beaches before a nourishment work, together with the main acceptance criteria when choosing the appropriate sand for replacement.