Quasi‐Universal Length Scale of River Anabranches

Abstract

AbstractLooping patterns, where channels divide and reconnect further downstream, are widespread in natural rivers. Here, we build an extensive dataset of different gravel‐bed and sand‐bed rivers around the world encompassing a wide range of physiographic and sedimentological conditions. Field data show the existence of quasi‐universal relations for the anabranches length when scaled with bankfull hydraulic geometry variables of the main upstream channel. The dimensionless length is found to be nearly slope‐invariant, identifying a clear difference with respect to deltaic systems. This scaling relationship is explained by interpreting the dynamics of river loops as basically controlled by a two‐way interaction between their constitutive elements, bifurcations and confluences. The identification of a quasi‐universal length scale provides insight on the morphological evolution of multi‐thread networks and constitutes a key information for the design of self‐sustaining river restoration interventions.