Assessment of the Relationship between Coastal Morphometry, Bottom Dynamic Conditions and the Critical Depth

Coastal sediment can be classified by functional bottom type, depending on whether cohesive fine material is eroded (E), transported (T) or deposited/accumulated (A) there. The assessment of such bottom dynamic conditions is useful in many ways, including as a fundament for structuring mass balance models. In this paper more than 200 recently investigated Swedish coastal areas were analyzed using geographic information systems (GIS). Statistical relationships between morphometry, the average proportion of A-areas (BA) and the average critical depth (DTA), which separates ET-areas from A-areas, were investigated. Many morphometric parameters showed significant correlation with both BA and DTA and multiple regression models were obtained that could explain much of the variation in these parameters. Parameters describing sheltering effects from islands, mean depth and mean slope were important in this context. Large differences were found in empirical BA-values from two different sources. Furthermore, a new empirical dataset was presented for 209 Swedish coastal areas.