Sedimentation in a disequilibrium river-dominated estuary: the Raša River Estuary (Adriatic Sea, Croatia)

ABSTRACT This paper examines sediment transport, sedimentation and properties of suspended matter and sediments in the Raša River estuary, a small, rock‐bounded, microtidal, low‐wave‐energy karstic estuary in the north‐eastern Adriatic. The Raša River is characterized by large variation in water flow and variable load of mineral particles. More than 90% of this load is brought into the estuary as fine‐grained suspended matter, consisting of only 24–36% of carbonates, the rest being clays. Sedimentation occurs at the salt wedge, resulting in a prograding estuarine delta. Salt‐induced flocculation is the predominant process of sediment deposition. The Raša estuary is infilling with sediment, and classifies as a disequilibrium estuary. We propose a modification of Cooper's (1993) classification scheme to include river‐dominated, disequilibrium estuaries, with the Raša River as an example.