My dissertation research demonstrated that climate-dependent chemical weathering can influence the patterns of river erosion at the scale of landscapes (Murphy et al., Nature, 2016). Inspired by my previous field observations of rock mechanics, I began to explore the interactions of weathering and fluvial abrasion at a smaller spatial scale: individual topographic roughness features along streambeds.
This research demonstrated that weathering of bedrock exposed in ephemeral rivers can drive systematic spatial variations in erodibility across streambeds (Murphy et al., Geology, 2018). Due to the combination of weathering and bedload abrasion, I found that upstream-oriented faces exhibited a stronger mechanical strength than downstream faces in the same reach. Previous work on morphodynamics in bedrock channels (i.e., the interactions of streamflow, sediment transport, and topography) has assumed there is uniform erodibility along streambed reaches. This assumption does not hold in all rivers, and given the implication for the evolution of bedorck rivers, I am continuing to explore the interactions of weathering and abrasion.