High‐Resolution Channel Geometry Reveals Contrasting Styles of Gravel River Adjustment

Abstract Rivers self‐organize to convey water and sediment, giving rise to robust downstream scaling between channel geometry and drainage area, underpinning landscape evolution models. However, these relations rely on limited observations per watershed. We quantify downstream changes in channel slope and bankfull width for six gravel rivers. We develop a novel method to automatically extract bankfull width and determine high‐resolution (10‐m), catchment‐specific width‐area scaling, revealing new insights on the covariation between slope and width hidden in large data compilations. We identify a threshold slope, below which average width is slope‐independent. Notably, slope and width deviations display contrasting patterns depending on the channel's elevation profile. Deviations are anticorrelated when knickpoints are present and correlated when they are absent. High‐resolution, catchment‐specific scaling laws capture systematic, interpretable deviations reflecting underlying controls on channel adjustment and fluvial erosive power. With growing availability of high‐resolution topography, our approach provides new insights into river process and form.