Modeling bed-material sediment transport on a river network

Understanding how river-channel processes aggregate at the watershed scale is becoming increasingly important for watershed managers. Here we describe a network-based framework for modeling sediment transport in a watershed that involves (1) decomposing the landscape into a connected network of elements including river channels, lakes, etc., (2) spatially and temporally distributing inputs of sediment according to a sediment budget, and (3) tracking these inputs through individual landscape elements via process-based time delays. The resulting bed-material sediment transport model described herein includes recurrent inputs informed by a sediment budget and also lake and in-channel storage with feedback between in-channel storage and channel slope. The model was used to simulate spatial and temporal bed-sediment depths on an entire river network at the watershed scale.