Author: James White, RRC
| Yesterday (Tuesday 4th May) I attended the first day of ‘International Surface Velocimetry’ workshop organised by Prof. Dan Parsons (University of Hull) and Nick Everard (UK Centre for Ecology and Hydrology). The workshop was established to allow various presenters from around the world to present their research and tools centred on measuring riverine surface velocity flows. Such research is of direct interest to the RRC as surface water velocities are intrinsically linked to key river processes such as overbank flooding and bank erosion. In total, there were 13 presentations focussed on different techniques that varied in terms of the technology used (e.g. Acoustic Doppler Current Profiler, Unmanned Aerial Vehicles imagery), the spatial scale the method was being applied at (e.g. habitat, reach) and the end user (e.g. practitioners, citizen scientists). |
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One presentation given by Anette Eltner at the Technische Universität Dresden was of particular interest to the RRC. Within her presentation, Anette described the methodological procedure from which aerial imagery collected via drones could be used to derive the spatial distribution of surface water velocities at the reach-scale. They did so at three study sites across Europe (Mulde, Germany; Sajo, Hungary; Pulmanki, Finland). Initially, different correction techniques were applied to accurately capture the river bathymetry. Following this, the drone imagery was used to identify specific surface water features (or particles) which could be traced between separate images to derive flow velocity. The image below shows an example of this from an article (Figure 5e) published by the same author. When compared against velocity measurements collected in situ, velocities collected via the technique presented by Anette yielded an accuracy value of up 89% at one site. The authors were then able to use bathymetric and flow velocity measurements to calculate river discharges, which could also afford a useful means of tracking water volumes across larger spatial scales (compared to individual flow gauges at a fixed point). |
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Another presentation of interest was the ‘flow on the go’ tracking technology (https://flowonthego.org/) presented by Jonny Higham at the University of Liverpool. This is a smartphone application where citizen scientists can take images and videos of different flowing water environments which can subsequently be used to calculate surface flows. The RRC was particularly interested in this technology given our links with different citizen science initiatives, including the ‘Measuring the Impact of Citizen Science’ (MICS) initiative (see here for more information). Jonny presented his background in studying aerodynamics of gas particle movements and how this information was then translated to examining water movements. He outlined the user interface of the flow on the go app and used a real-world example of how this could be used. The screenshot below from this online video shows a snippet of how the application functions. |
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