This thesis presents the result of measurements of sediment concentration due to currents and irregular waves. The measurements were conducted from April to September 1999, in the 'Lange Speurwerk Goot', a large flume in the Laboratory of Fluid Mechanics. The goal of the experiments, which are part of the European Research Program SEDMOC, was to find the influence of the grading of bedmaterial on the concentration verticals. In this report, only results are presented, both in tables and in graphs. No attempt has been made to analyse the data at this stage.