New methods for coupling climate-driven hydrology with hillslope and channel geomorphic processes at the watershed scale

Abstract

As human demand for natural resources grows, the historic hydrologic conditions that permitted certain slopes and channels to remain stable in the past are shifting. Consequently, relying on historic or observed data to inform management decisions, that may also affect slope and channel stability, is no longer reasonable and models that incorporate climate predictions are becoming increasingly necessary. Many numerical approaches for modeling watershed-scale sediment production and transport response to land use and climate already exist but they share similar shortcomings. This thesis improves hydrology-driven, watershed-scale sediment production and transport modeling methods and understanding. First, I examine hydrologic representation and its impact on modeled-network-scale sediment transport. Then, I develop a new landslide runout model, called MassWastingRunout, suitable for predicting probabilistic runout extent, sediment transport and topographic change. Finally, as part of a study on climate change impacts on landslides, I develop a new method for coupling climate and hydrology to sediment production and transport models, called DistributedHydrologyGenerator. The new modeling techniques are coded in Python and implemented as components of the package Landlab. This thesis ends by synthesizing findings and tools from each section and briefly proposing a watershed-scale sediment production and transport modeling framework for future work.