Multi-frequency acoustic backscatter measurement can be used to observe spatial profiles of suspended sediment. The use of multiple frequencies helps to resolve mean particle size by exploiting the frequency-dependent relationship between scattering intensity and particle size. The AQUAscat acoustic backscatter profiler uses this principle to estimate mean particle size and concentration profiles with spatial resolution between 2.5 mm and 40 mm. The instrument is usually configured to acquire profiles of backscatter amplitude. However, an infrequently used setting on the standard instrument provides direct access to the quadrature sampled backscatter data stream, from which amplitude is normally calculated. By using the in-phase and quadrature sample data, the backscatter phase can also be calculated. The rate of phase change between profiles can then be related to the along-beam velocity of the scatterers. For a vertical beam, in the absence of vertical water motion, this is the settling velocity. This paper evaluates datasets and data processing approaches for estimating particle settling velocity. The experimental data is acquired with various types of laboratory generated suspensions, including glass spheres, sands, and flocculating mud. Besides extracting settling velocity data, the processing aim is to enhance the quality of acoustic backscatter data analysis.

In 2012, Aquatec launched an equipment award scheme for postgraduate students and early career scientists. Successful recipients with limited budgets gain free access to high quality subsea instrumentation for a laboratory or ‘eld campaign of up to three months, plus a travel grant to allow them to present their work at a conference. So far there have been 11 successful awardees who have applied from or deployed instruments in 13 countries spanning ’ve continents, in *umes, lakes, rivers, and coastal seas. In this paper, we present an overview of the most successful award projects. We also evaluate the impact of the scheme on the award recipients’ chosen project work and how it in*uenced their future career. The evaluation draws on analysis of the recipient study reports and the use of questionnaires and interviews. The scheme has also suffered the occasional setback. We attempt to identify some of the potential pitfalls of such a program, and highlight the key factors that lead not only to the best student experience, but also a positive outcome for the awarding company