Author(s): Francesco Caponi; Annunziato Siviglia

Linked Author(s): Annunziato Siviglia

Keywords: No Keywords

Abstract: Riparian vegetation has been widely recognized to influence and respond to fluvial morphodynamic processes altering flow and sediment fluxes. In particular, plant roots (below-ground biomass) significantly contribute to stabilize riverbed substrates by increasing sediment cohesion and to guarantee plant anchorage withstanding uprooting and excavation by flow erosion. So far, research has mainly focused on the interactions between flow and plant canopy (above-ground biomass), often disregarding or oversimplifying plant root biogeomorphic feedbacks. The goal of this work is to understand and quantify such feedbacks. This is obtained through a modeling approach that includes a description of the vertical root distribution and its effect on morphodynamic processes and enables a more accurate description of the uprooting mechanism. We perform a series of numerical experiments investigating the riverbed evolution of a straight channel in presence of a vegetation patch, which is characterized by an above-ground biomass and either by shallow or deep root systems. The equilibrium configurations of the riverbed demonstrate a fundamental control by plant roots, able to delay vegetation removal controlling the soil depth at which uprooting occurs. Our results highlight the pivotal role of the uprooting on shaping river morphology and, although the basic configuration investigated, provides a quantitative basis for further investigations by considering more complex river morphologies.

DOI:

Year: 2018