Scaling properties of laboratory-generated river networks

Selected laboratory experiments were carried out in the Hydraulic Engineering Laboratory at University of Basilicata, to explore scaling properties and self-organization tendencies of river networks. Experiments were made using a 1.5 m by 1.5 m basin-simulator-box with an outlet in the middle of the downslope-end side. The experimental landscape was weakly-cohesive soil mainly made by clay and silt. A system of micro-sprinklers delivered an almost uniform artificial precipitation. Simulations were performed at a constant rainfall intensity of 100 mm/h using different planar slopes. An additional experiment was also made to consider the base-level control. Digital elevation models (DEMs) of the evolving landscape were achieved through detailed soil surveys with a laser distancemeter and/or a laser scanner. The river networks were extracted from the DEMs using the D8 algorithm. Channel networks were ordered using the Horton-Strahler ranking as well as the Shreve topological classification. Hence, scaling laws were analysed to explore whether the generated systems resembled natural river networks. Thus, findings are provided on basin allometry, exceedance probability of basin areas and stream lengths, and slope-area relationship.