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UK Centre for Ecology & Hydrology (GB)


FluViSat is a proof-of-concept study that demonstrates the potential of satellite-collected video imagery to provide accurate and timely quantification of water movements and river flows for the benefit of water management globally. The study is being led by the UK Centre for Ecology and Hydrology, in partnership with the Luxembourg-based company, RSS-Hydro, and the Queensland Government, Australia.
According to the OECD, floods affect 250 million people and cause 40 billion USD in losses on an annual basis. In addition, the demand for water for people, industry and agriculture is continually growing, placing severe stress on water availability. Freshwater management requires quantitative observations of how much water is flowing through and is being stored within river catchments, and yet across much of the world, water monitoring capabilities fall short of requirements.
Previous efforts to determine river discharge from Earth Observation (EO) data have largely been based on the determination of water surface height and extent alone, and lacked the critical parameter of flow speed. Two recent advances are leveraged by the FluViSat project to bring a step change to satellite based river flow observation capabilities. The first is the availability of large satellite networks, such as the SkySat constellation operated by Planet Labs that combine very high-resolution imagery with frequent revisit times. The second is the development of digital video-based ‘surface velocimetry’ methods for streamflow determination. Surface-velocimetry techniques work by tracking the movement of visible features on the water’s surface through the frame of digital video files, in order to quantify the movement of flowing water.
By combining these surface-velocimetry techniques with very high resolution video from the SkySat satellites, the FluViSat project has demonstrated that the speed of flow of water on the Earth’s surface can be accurately determined for a range of river sizes, types and locations. This in turn greatly improves the accuracy of remote observations of river discharge and flood peaks.

By comparing surface velocities and river discharges from data collected simultaneously from satellite video, low altitude drone video and boat-mounted Acoustic Doppler Current Profilers (ADCP) during high flow events in rivers and tidal locations in the UK, Austria, Australia and Japan, the international project team has demonstrated:
  1. The potential of satellite-based surface velocimetry methods in hydrometry, and
  2. The potential of innovative new EO techniques for water resource and flood risk management globally
Above: The FluViSat validation concept. Satellite video results compared to aerial drone and ADCP derived results (Credit: Nick Everard, UKCEH)










The primary customers for this innovation are water resource managers, environmental regulators, and those involved risk and disaster mitigation and management. However, the successful proof of concept can also be beneficial to the re-insurance community, hydro-meteorological systems modellers, as well the EO data service providers.

The project can greatly improve global hydrological understanding by enabling flow velocity and discharge data collection from previously ungauged locations, and locations that may be hard to reach. The new method also has the potential to significantly improve the observation of the hugely damaging and disruptive overland flows that accompany many major flood events. The method can benefit and complement existing risk reduction and emergency management systems, improving preparedness and reducing flood impacts. Finally, the cost effectiveness and safety of river flow measurements can be improved significantly compared to mobilising monitoring teams to visit remote locations.
Above: Water velocities derived from satellite video. River Indus, Pakistan, September 2022 (Background image courtesy of Planet Labs PBC).
Water flow velocity and discharge estimates are also essential to the management of diffuse pollutant fluxes, general water quality monitoring, and water-use for irrigation and recreation, as well as in the modelling and prediction of river morpho-dynamics. As such, the method derived from this project can benefit environmental regulators and water quality management.Through the success of the feasibility study, this project provides vital insights into the needs and values of possible future Sentinel video missions, but more importantly, it can demonstrate the potential value of satellite video imagery for scientific, societal, and commercial activities.

Following the successful demonstration of the FluViSat satellite velocimetry innovation, an extension was granted to expand the proof-of-concept to explore the validity of using high framerate still imagery from space to estimate surface flow rates. The team is also leveraging the existing ESA Earthnet project PP0087756 titled “Measuring global streamflow and drought impacts with Planet SkySat ultra-high resolution satellite imagery” to explore the potential of still frame imagery from Planet Labs, who will also be providing video imagery to help validate results from the still frame images. The extension period is being used to refine the FluViSat video method, in particular the pre-processing of imagery (both video and still frame) to expand the range of locations and conditions in which the methods can be used, and to increase the accuracy of velocimetry results. Finally, the project is trying to develop a framework to enable responsive satellite-based observations when extreme hydrometeorological events occur.

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UK Centre for Ecology & Hydrology (GB)
  • RSS-Hydro (LU)