Alluviation of a side-channel by bed material load: field measurements and modelling
| Autor: | Carles Ferrer-Boix, J.P. Martín-Vide, Alfredo Ollero, Júlia Boix Oliva |
|---|---|
| Přispěvatelé: | Universitat Politècnica de Catalunya. Departament d’Enginyeria Gràfica i de Disseny, Universitat Politècnica de Catalunya. Departament d'Enginyeria Civil i Ambiental |
| Jazyk: | angličtina |
| Rok vydání: | 2021 |
| Předmět: |
Hydrology
Alluviation Enginyeria civil::Geologia::Hidrologia [Àrees temàtiques de la UPC] 010504 meteorology & atmospheric sciences Flood myth Chutes Context (language use) 010502 geochemistry & geophysics Gállego River (Spain) Side-channels 01 natural sciences Current (stream) Alluvial streams Bifurcations Channel pattern Bedload transport Cursos d'aigua -- Sediments Gravel-bed rivers Meander Geology Bank erosion Beach morphodynamics 0105 earth and related environmental sciences Earth-Surface Processes Bed material load |
| Zdroj: | UPCommons. Portal del coneixement obert de la UPC Universitat Politècnica de Catalunya (UPC) |
| Popis: | In this research, we explore the alluviation process of an artificial side-channel built in August 2015 and designed to alleviate bank erosion risks on the main river. The study area is located on the lower Gállego River, a meandering-wandering gravel-bed river draining the Southern Pyrenees. This river reach is still dynamic (i.e. chutes, meander migration and other riverine processes are often observed during floods) despite the presence of three dams in the upper catchment, encroachments and extensive mining during the 1960s–80s that led to severe incision. In this research, we focus on the effects of bankfull-like flood events (Qpeak¿=¿354¿m3/s) between February 2016 and February 2017, which alluviated 62% of the side-channel. This research aims at finding the physical mechanisms that explain the alluviation process and at putting them in the general context of the current geomorphic trend of the Gállego River in response to past and ongoing impacts. The causes of the alluviation are studied through collecting and analysing field data, which in turn, are used as input in a novel modelling strategy that includes one-dimensional hydraulic modelling, semi-empirical expressions to obtain the sediment supply entering the side-channel system and a morphodynamic model able to deal with granular sediment mixtures in compound channels. The analyses of the numerical results along with the recent history of impacts and general channel pattern adjustments help us understand about the morphodynamics mechanisms responsible for the alluviation of the side-channel. |
| Databáze: | OpenAIRE |
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