DEVELOPMENT OP A SEDIMENT TRANSPORT MEASURING SYSTEM

Abstract

A new method for continuously recording sediment concert - trations with high accuracy has been developed. It is proposed to apply the method for In-situ measurements in connection with investigations of tidal control and sediment transport induced by shipping traffic. The operating principle is as follows: at the measurement location, sedime~nt laden water is continuously sucked-in by means of a pump and is forced under pressure into a hydrocyclone ( solid bowl centrifuge ) through a delivery pipe of varying length. Here the extracted sediment flux (particle size *> 5 nm) is delivered by the shortest route to a settling tank and continuously weighed under water (wet-weighing). Following calculation and appropriate adjustment to the sample discharge ( Q ) the weight increase for selected time intervals ( AG (At)) yields the mean concentration for the time interval ( c (At)) in weight / unit volume ( mg/1 ) (direct measurement, calibration not required ). Details and experiences of the 3 major development stages will be described. A fully-automatic instrument for continuously measuring nonsteady sediment movement is now available. The instrument may be installed above as well as below water as desired.