The effect of vegetation on sediment dynamics gains increasing attention for coastal protection. To assess these effects, laboratory experiments with live or artificial vegetation are widely applied. A major challenge in such experiments lies in the measurement of bed level and bedforms since standard optical and acoustic measurement techniques cannot obtain data below vegetation canopies.
Here, we tested underwater photogrammetry and an adapted sediment-erosion-bar (SEB) for the assessment of sediment dynamics in and around an artificial seagrass meadow. First results show that SEBs are capable of obtaining data even within dense vegetation, however, they indicate limitations in SEB accuracy due to pin dimensions and sinking into soft sediment. Underwater photogrammetry showed first promising results regarding bed level detection outside the meadow, but failed to obtain data within the dense meadow. Both methods are potential alternatives to existing bed level measurement techniques, provided that their individual limitations are considered.
