Sand grains, bedforms and the wave boundary layer cause roughness for tidal currents. This paper reports roughness
and current shear stress in calm weather and storms derived from 1900 hours of detailed flow measurements on a sandy
shoreface, 2 km off Noordwijk, The Netherlands. Two methods are employed: fitting logarithmical velocity profiles to
data of 3 to 7 sensors, and the inertial subrange method from the spectra collected at 2 Hz. The results are compared to
observed bedform dimensions. Various technical problems are discussed. The roughness decreases for increasing
current velocity in Hm0 waves <2 m, but increases for larger waves. Individual events show contrasting trends that are
probably related to bedform development. Recommendations for future instrumentation and for further analysis of this
data are give