Two-dimensional numerical modeling of wood transport

Abstract

The transport of wood material in rivers has been the subject of various studies in recent years. Most research has focused on the ecological and geomorphologic role of wood, its recruitment processes and spatial distribution in streams. In this study, we focused on wood transport dynamics, and we have developed a numerical model to simulate wood transport coupled with a two-dimensional (2D) hydrodynamic model. For this purpose, wood drag forces were incorporated as additional source terms into the shallow water equations, which are solved together with wood transport by using the finite volume method. This new tool has been implemented as a computational module into 'Iber', a 2D hydraulic simulation software. The new module analyzes the initial motion threshold of wood based on the balance of forces involved in the wood's movement, and computes the position and velocity of differently shaped logs using a kinematic approach. The method also considers the interaction between the logs themselves and between the logs and the channel walls or boundaries.Flume experiments were used in a straight channel with obstructions to validate the model's capacity to accurately reproduce the movement of floating logs.

Characterization of wood‐laden flows in rivers

“…Flume experiments and modelling may help to understand WLF dynamics. Mazzorana et al, 2011;Ruiz-Villanueva et al, 2014a;Persi et al, 2018). Following this multi-phase approach, numerical models have been developed using different frameworks, accounting or not for the interphase interactions (e.g.…”

“…The three approaches shown in Equations (1), (2) and (3) were used here in a first attempt to reproduce, by numerical modelling, the flow front of some of the WLFs observed in the videos. Iber was initially developed to perform hydrodynamic and sediment transport simulations, but was later coupled to different modules such as the wood transport module (Ruiz-Villanueva et al, 2014a) or the wet snow avalanches module (Torralba et al, 2017). The aim of the simulations was to estimate a range of parameters that fit with the observed WLFs, but also to better understand the mechanics of such flows.…”

Management of Large Wood in Streams: An Overview and Proposed Framework for Hazard Evaluation

“…Investigators working in mountainous regions of Europe have recently developed two‐dimensional, integrated modeling approaches that use GIS software to evaluate the recruitment of large wood to river corridors, as well as entrainment and transport of the large wood based on the balance of hydrodynamic and resistance forces acting on individual wood pieces (e.g., Mazzorana et al ., , ; Ruiz‐Villanueva et al ., , b). These modeling approaches incorporate infrastructure scenarios such as locations of bridge piers or abutments and can be used to assess hazards during floods that transport large wood (Mazzorana et al ., ).…”

Large wood recruitment and transport during large floods: A review

“…The capacity to reproduce the movement of floating logs was validated through using a straight channel with obstruction elements on both sides of the channel. The numerical model was applied to a Spanish mountain stream with a catchment area of 16 km 2 where a flood event with a high degree of LW transport took place in 1997(Ruiz- Villanueva et al, 2014a). They simulated a bridge-clogging process and reconstructed the wood deposition patterns by modelling individual pieces of wood moving with the water flow and interacting among them and with the bridge.…”