The UKCEH DroneFlow project: Assessing the potential of drone-based velocimetry across a range of UK river types and flow conditions

The measurement of streamflow in the world’s rivers is critical to the management of water as a resource and to predicting and managing the impacts of potentially damaging hydrological events such as major floods. Aerial drones capable of capturing high-resolution digital video have shown enormous potential to improve observations of river and floodplain flows and to benefit science and research projects where streamflow must be measured. However, their effectiveness, operational readiness, and the accuracy of observations in UK rivers is at present largely unknown.
This research closes this knowledge gap by undertaking a thorough assessment of the performance and usability of aerial drones over a wide range of locations and conditions. 
Furthermore, as the technique has yet to fully transition from the research domain to operational use, there remain a number of practical challenges and uncertainties over how and where drone-based methods can be applied. This project will identify and address limitations and create further opportunities for the research community to help refine the methods to become effective for widespread operational use. 
Low-cost consumer-grade aerial camera drones were deployed at a range of sites in England and Scotland and the resulting river discharge results compared against reference values obtained with Acoustic Doppler Current Profilers (ADCPs) to assess their potential for making accurate measurements of river discharge. A total of 45 comparisons were made at 28 sites, almost all of which were hydrometric river flow gauging stations. At some sites, measurements were made at more than one location.
The drones used were low-cost consumer-grade models available from electronics and photography stores for between €500 and €1200 – orders of magnitude cheaper than traditional discharge measurement tools and equipment.