High-resolution hydrometric monitoring of rivers is important because the climate crisis severely affects frequency and magnitude of extreme events and flood/drought risks are evolving fast. However, hydrometric monitoring data is scarce and lacks spatial resolution and coverage, particularly in remote and hard-to-reach rivers in alpine, Arctic and tropical regions. Advanced in-situ monitoring technologies have to be combined with satellite earth observation (EO) to obtain accurate, reliable, long-time and spatio-temporally resolved information for effective decision support, risk assessment, investment analysis in the context of climate change adaptation, and operational forecasting, surveillance, and management of rivers.
Traditional in-situ hydrometric monitoring of rivers is station-based. Water surface elevation (WSE), flow velocity, bed geometry and river discharge are measured using sensors that are installed in-situ, either in direct contact or in close proximity to the flow. In-situ station-based monitoring infrastructure is vulnerable and often fails during extreme flooding events, when the value of information is very high. Station-based monitoring networks lack spatial resolution and have been declining in many regions, particularly in remote and hard-to-reach areas. Data accessibility is increasingly restricted because of growing conflicts between countries over water resources allocation.
UAWOS develops a drone-borne water observing system providing key hydrometric variables (bathymetry, flow velocity, discharge, water surface elevation) at high spatial resolution and coverage (Figure 1). Because the system works airborne and contactless, it is ideally suited for remote and hard-to-reach areas and extreme physical conditions. UAWOS integrates airborne data streams with water and land elevation datasets available from different satellite EO missions, including Sentinel-3, ICESat-2 and SWOT.
