Estimating the deposition of river-borne suspended matter from the joint analysis of suspension concentration and salinity

A simple method has been proposed for estimating the deposition and mixing rates of river-borne suspended matter and mapping the deposition intensity in near-estuary sea areas. The method involves the joint analysis of data on the total suspended solids (TSS) concentration and salinity. The relative content of river runoff in seawater is determined from the salinity value. If the suspended matter is subject to deposition, its concentration would be fully determined by the relative content of river water in the seawater and could be calculated based on salinity. However, the factual TSS concentration is usually lower than that estimated from salinity, because of deposition. Hence, the amount of TSS deposited from a specific water parcel can be obtained as the difference between the concentration prescribed by the linear mixing of river and seawater masses and the factual concentration. This scheme has been implemented using high-resolution data collected in field campaigns in the Black Sea near the Mzymta River mouth. The TSS concentration was obtained using ultraviolet fluorescence lidar, and salinity was measured by a pump-through CTD system.