Scientists at HR Wallingford have received research funding for a pilot project aimed at investigating the measurement of cohesive sediment properties using high frequency underwater acoustics.
The primary aim of this project is to derive semi-empirical algorithms that can be used to calibrate Doppler sonar signals in terms of the relationship between acoustic backscatter intensity and suspended sediment concentration using results obtained from field measurement campaigns.
An additional objective of the study will be the development of a ‘best practice’ approach to the acquisition and processing of data from this type of instrument. Over the last 20 years Doppler sonar have proven to be powerful tools for studying flows under both waves and currents, and the response of mobile sediments to their forcing. Consequently, the data captured by such instruments is vital for calibrating and validating the complex 3D hydrodynamic and sediment dynamic models that HR Wallingford is developing. However, as with all field datasets, the data is only of use if it is of high quality and has been correctly specified and surveyed.
Taking a ‘black box’ approach to the deployment and operation of these highly sophisticated and versatile instruments under values their potential merits and can, in certain cases, lead to the delivery of data which is less than optimal.
Dr Andrew Manning, the project leader at HR Wallingford , explains: “ Our intention is that this research project will put forward documentation which will spell out the operational benefits and trade-offs, which will be of use to all users of these instruments. We are keen to collaborate with colleagues in the industry to achieve these ends .”
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Dredging Today Staff, July 24, 2012; Image: HR Wallingford