Engineer Research and Development Center, Coastal and Hydraulics Laboratory Vicksburg United States
The construction of artificial berms in the nearshore environment using dredged material has been in practice since the 1930s. While considerable progress has been achieved from both theoretical and practical considerations, placement decisions were often heuristic, based on experience, or required tedious calculations. For that reason, the Sediment Mobility Tool SMT was developed to make rapid, preliminary assessments of nearshore placement areas and berm migration. This technical report provides a comparative analysis between SMT results and historical field observations for nine nearshore placement projects with diverse berm geometries, sediment characteristics, and wave climates. The SMT correctly predicted nearshore berm sediment mobility and migration directions for eight of the nine historical berms studied. These sites were typically associated with shallow placement depths and energetic wave conditions. Likewise, the SMT correctly predicted stable berms for two of three sites. For one case in particular, the SMT correctly predicted a stable berm in contrast to the expectation that the berm would mobilize, which underscores the value of SMT to make informed decisions during project planning. The few discrepancies between SMT predictions and observations may be partly explained by berm geometry mound versus linear berm, whereby application of the tool to mounded geometries may not be suitable.