THE MEASUREMENT OF CONSTITUENT CONCENTRATIONS IN NONHOMOGENEOUS SEDIMENT SUSPENSIONS USING OPTICAL BACKSCATTER SENSORS

A method is proposed for estimating the concentrations of the constituents of nonhomogeneous sediment suspensions using optical backscatter sensors. The method is predicated on the assumption that constituent interaction (e.g. grain shielding and multiple scattering) does not significantly affect sensor response. This fundamentally linear approach was verified by laboratory tests of a backscatter sensor in a range of silt/sand mixtures. Implementation of the method will require further development of the optical backscatter sensor or possibly the pairing of an acoustic backscatter sensor with an optical sensor. The method has the potential for resolving small-scale spatial and temporal changes in the suspended-sediment population, and therefore could be employed in studies of winnowing and bed armouring, for example.