Application of a new international protocol to measurement of sediment release from dredgers.
Type:
Presented during:
WODCON XVII: "Dredging in a Sensitive Environment" - 2004, Hamburg, Germany
Authors:
John Land, Neville Burt, Hans Otten
Abstract: Two major field measurement exercises have been carried out as part of continuing research to develop fieldcalibrated software (TASS - Turbidity Assessment Software) capable of predicting how much sediment is released into suspension during dredging operations. These were the first applications of a field measurement protocol commissioned by VBKO and developed by HR Wallingford and Dredging Research Ltd. The measurements were designed to test the protocol in the real world and to obtain calibration data for the software.
The work demonstrated that there is a clear need to follow the protocol in detail in order to obtain good and meaningful data.
The first measurements, involving a grab dredger (Seal Sands) working on the River Tees was carried out in May 2000. The second set of measurements were carried out using a trailing suction hopper dredger (Cornelia) working in the port of Rotterdam in June 2002. By this time the protocol had been further developed. However, working with a trailing suction hopper dredger introduced an extra dimension of complexity because the dredger itself was continuously moving.
Following the experience gained during the trials, and having carried out an international review of the protocols, the first public version was released in August 2003. On the basis of this it is hoped that new measurements will be taken in a way that will make them useful for calibrating and validating the predictive software TASS.
The paper describes the protocol and the experiments carried out to test it, drawing conclusions about its future contribution to solving the problems of assessing the environmental effects of sediment released by dredging operations.