Simulating the Influence of Channel Morphology on Particle Travel Distance
Abstract
Fundamentally, bedload transport is the aggregation of the movement of individual sediment grains. These grains move intermittently in a series of steps and rests that resemble a random walk. The cumulative distances these particles move from initial entrainment to final deposition location is termed the path length and has been described by EHS-style stochastic models since Einstein (1937). The emphasis of these models on step lengths and rest durations yields some nice results; however, this framing neglects the influence that channel morphology exerts on the entrainment and trapping of particles. Consider two particles subjected to a flow, one located near a 'trapping location' (e.g. a bar) and one further away. One would expect the former particle to travel a shorter distance than the later, however current models are unable to capture this effect. Here, we developed a model that incorporates this location-specific trapping behavior and determine if it improves on the performance of current stochastic path length models.
In this study, we treat the movement of tracer particles as a stochastic survival process. The model is trained using multi-year tracer data sets from Halfmoon Creek (CO, USA) (Bradley, 2017) and East Creek (BC, CAN). The model performs favorably in comparison with EHS-style models and flexibly recreates locations of preferential deposition. Through its focus on deposition locations, this model provides a novel way to explore the impact of channel heterogeneity on bedload transport measurements and particle dispersion.- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFMEP53H2273M
- Keywords:
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- 1810 Debris flow and landslides;
- HYDROLOGY;
- 1862 Sediment transport;
- HYDROLOGY;
- 1865 Soils;
- HYDROLOGY;
- 1899 General or miscellaneous;
- HYDROLOGY