Spaceborne radar delivers the first planet-wide estimate of river flow and suspended sediment

A satellite mission designed to survey surface water has produced the first global dataset that estimates both how much water rivers are moving and how much sediment they carry, covering channels above a practical width threshold. The dataset is built on wide-swath radar interferometry observations and combines water-surface heights with reach-scale modelling to infer flow volumes and suspended material concentrations. Because in-situ gauges are unevenly distributed—often absent in remote, politically complex or rapidly changing basins—the space-derived product plugs many of the observational holes that limit regional hydrology and sediment-transport science. The dataset’s spatial coverage is bounded by a detectability floor near fifty meters of channel width, so small headwater streams remain underrepresented but major reaches and large drainages are well captured. Temporal sampling is governed by the satellite’s orbit pattern, producing repeated passes on a roughly three-week cadence that trade continuous monitoring for global breadth. For operational users—flood forecasters, reservoir operators, irrigation planners—the dataset represents a complementary layer rather than a drop-in replacement for gauge networks, useful for situational awareness and where local instruments are missing or offline. Scientifically, simultaneous estimates of discharge and suspended sediment enable improved budgets of sediment flux to deltas and coasts, and a clearer assessment of how land use and extreme rainfall events mobilize soil. Methodological challenges remain: converting surface-height observations into robust discharge requires reach-specific hydraulics, bathymetry assumptions or calibration with ground data; estimating sediment concentration from remote measurements introduces additional uncertainty linked to particle size, concentration ranges and optical/radar backscatter relationships. The product therefore shines brightest when fused with local gauge records and hydrodynamic models to constrain transfer functions and error bounds. Policy and water-resource decisions can benefit from the new global perspective, but practitioners must interpret the numbers in the context of cadence limits, detection thresholds and reach-level calibration needs. Over time, combining this mission’s outputs with denser satellite constellations, targeted in‑situ campaigns and model assimilation could drive a step-change in flood early warning and sediment management. The release marks a substantive advance in earth-observation hydrology, shifting some measurements from sparse spot checks to systematic planet-scale inventories while acknowledging remaining gaps in small-stream coverage and instantaneous temporal resolution.