Abstract
A fluvial catchment consists of unchannelized hillslopes drained by a channel network. Here we use a probabilistic algorithm to generate a set of scale-free, two-dimensional (2D) pixelized channel networks of increasing complexity. We then integrate reach-scale hydraulic geometry equations, originally developed for single gravel-bedded river reaches with the 2D networks to reverse-engineer the corresponding 3D topography of these 2D channel networks, once the outlet flood discharge and a characteristic bed grain size are specified. By incorporating hillslope-channel coupling, represented by a characteristic hillslope length and slope, we can fully specify the 3D topography of the entire watershed. Our results suggest that under appropriate constraints the equilibrium hydraulic geometry hypothesis can be extended beyond isolated river reaches to encompass entire fluvial landscapes.
Bio
Gary Parker is a specialist in the field of river and deep-sea sediment morphodynamics. He works with theoretical, numerical and experimental techniques to explain such problems as why and how rivers meander, how rivers self-construct their own channels, how rivers sort sediment, how turbidity currents run out long distances in the ocean and how they excavate submarine canyons. Parker’s interest in sediment transport in rivers was sparked by a class on the subject taught by Prof. L Brush of Johns Hopkins University in 1971. In 1972, Dr. Alvin Anderson offered him the chance to perform doctoral research on river meandering at the University of Minnesota. At the same university, Dr. Roger Hooke of the Department of Geology introduced him to supraglacial meltwater meandering. Parker was first a faculty member at the University of Alberta, Canada (5 years), and then at the University of Minnesota (25 years). He is currently Profossor Emeritus at the University of Illinois Urbana-Champaign having joined the University in 2005.