Global quantification of river confinement using MERIT DEM and SWORD centerline tools

River confinement is a key factor in determining the river’s morphology and its behavior, affecting flow properties, sediment transport, flood risk and floodplain development. Technological limitations have previously hindered global quantification of river confinement but advances in remote sensing and software now enable direct, automated measurements of river confinements. In this study we present a new method that combines the state-of-the-art global river centerline dataset SWORD, with the elevation model MERIT DEM to quantify river confinement across more than three million kilometer of rivers around the world. Our method measures the “entrenchment ratio”, which is the ratio between the valley width and the channel width. Secondly we measure the “confinement slope”, which is the gradient between the centerline and the surrounding topography. Our method enables us to identify five distinct classes. 1) Aggradational Rivers, with a negative confinement slope, due to sediment depositions raising the riverbed. 2) Flat Rivers, with no significant confinement slope. 3) Obstructed Rivers, partially confined by isolated topographic features. 4) Valley-confined Rivers, with a floodplain constrained by topography. 5) Entrenched Rivers, which have deeply incised V-shaped valleys. Our classification provides a globally consistent framework for quantifying river confinement, offering insights into river-landscape, flood risk, morphological change and fluvial infrastructure development.