Landscape-Scale Modeling to Forecast Fluvial-Aeolian Sediment Connectivity in River Valleys
Sedimentary landforms on Earth and other planetary bodies are built through scour, transport, and deposition of sediment. Sediment connectivity refers to the hypothesis that pathways of sediment transport do not occur in isolation, but rather are mechanistically linked. In dryland river systems, one such example is the transport of fluvial sediment by wind. However, predictive tools that can forecast fluvial-aeolian sediment connectivity at meaningful scales are rare. Here we develop a suite of extendible models for quantifying the availability of river-sourced sediment for aeolian transport as a function of river dynamics, meteorological data, and land cover over two decades across 168 km of the Colorado River in Grand Canyon, USA. We validate these models by comparison with more than 10 years of repeat lidar topographic data that quantify changes in sediment storage in a coupled river sandbar-aeolian dunefield setting. The models provide a path forward for directly linking fluvial hydrology with the management and understanding of aeolian landscapes.