Premium
A precipiton method to calculate river hydrodynamics, with applications to flood prediction, landscape evolution models, and braiding instabilities
Author(s) -
Davy Philippe,
Croissant Thomas,
Lague Dimitri
Publication year - 2017
Publication title -
journal of geophysical research: earth surface
Language(s) - English
Resource type - Journals
eISSN - 2169-9011
pISSN - 2169-9003
DOI - 10.1002/2016jf004156
Subject(s) - grid , context (archaeology) , flow (mathematics) , inertia , sediment , flow routing , flood myth , routing (electronic design automation) , erosion , geology , water flow , sediment transport , shallow water equations , computer science , hydrology (agriculture) , mechanics , geotechnical engineering , geomorphology , physics , geodesy , classical mechanics , geography , paleontology , computer network , archaeology
The “precipiton” method is a particle‐based approach that consists of routing elementary water volumes on top of topography with erosive and depositional actions. Here we present an original way to calculate both river depth and velocity from a method that remains embedded in the precipiton framework. The method solves the governing equations for water depth, where the water depth is increased by a constant quantity at each precipiton passage and decreased by a value based on a flow resistance equation. The precipitons are then routed downstream on top of the resulting water surface. The method is applicable even if the precipitons are routed one by one (i.e., independent of each other), which makes it simple to implement and computationally fast. Compared to grid‐based methods, this particle method is not subject to the classic drying‐wetting issue, and allows for a straightforward implementation of sediment transfer functions between the river bed and running water. We have applied the method to different cases (channel flow, flow over topographic barriers, and flood prediction on high‐resolution lidar topography). In all cases, the method is capable of solving the shallow water equations, neglecting inertia. When coupled with erosion and sediment transport equations, the model is able to reproduce both straight and braided patterns with geometries independent of grid size. Application of the model in the context of multithread rivers gives new insight into the development of braiding instability.