Projekt

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Eco-morphodynamic modelling for gravel bed rivers

Gesuchsteller/in Siviglia Annunziato
Nummer 159813
Förderungsinstrument Projektförderung (Abt. I-III)
Forschungseinrichtung Versuchsanstalt für Wasserbau, Hydrologie und Glaziologie ETH Zürich
Hochschule ETH Zürich – ETHZ
Hauptdisziplin Geomorphologie
Beginn/Ende 01.10.2015 - 30.09.2018
Bewilligter Betrag 176'507.00
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Alle Disziplinen (2)

Disziplin
Geomorphologie
Fluiddynamik

Keywords (4)

river engineering; riparian vegetation; numerical modelling; fluvial geompephology

Lay Summary (Italienisch)

Lead
Nell'ambito di un contesto caratterizzato da forti cambiamenti, una gestione sostenibile dei corsi d'acqua deve garantire protezione dalle piene, disponibilità della risorsa idrica e salvaguardia degli ecosistemi fluviali.
Lay summary

Capire e predire le interazioni tra la vegetazione riparia e la morfologia fluviale causate da cambiamenti climatici, differenti scenari di gestione della risorsa idrica e riqualificazione fluviale, è cruciale al fine di determinare le traiettorie evolutive dei corsi d'acqua. In questo contesto, l'obiettivo di BASEveg è quello di quantificare importanti processi morfologici che fino ad'ora sono stati solamente descritti qualitativamente. A tal fine verrà sviluppato un modello quantitativo fisicamente basato integrando competenze di tipo eco-morfologico e di modellazione numerica. Quindi BASEveg si propone di:
- migliorare e sviluppare ulteriormente il modello che descrive la dinamica della vegetazione da includere in un modello numerico bidimensionale già esistente capace di descrivere cambiamenti morfodinamici;
- analizzare le differenze tra morfologie vegetate e non vegetate quantificando le soglie che le discriminano in termini di intensità delle piene e rapporto tra la frequenza delle piene e il tempo di crescita della vegetazione;
- analizzare e modellare le interazioni morfologia-vegetazione in un tratto del fiume Tagliamento nel NE italiano, che è un corso d'acqua intrecciato fortemente dinamico. 
Il progetto verrà sviluppato presso il Laboratorio di Idraulica, Idrologia e Glaciologia (VAW) del Politecnico Federale di Zurigo (ETH). Il modello sviluppato ha le potenzialità per poter rispondere sia a questioni legate alla ricerca di base sia a questioni di tipo applicativo.

Direktlink auf Lay Summary Letzte Aktualisierung: 01.09.2015

Lay Summary (Englisch)

Lead
River managers and a society that aims at a sustainable interaction with the fluvial system are challenged by the need to ensure flood protection, water resources availability, and ecosystem health in a changing environment.
Lay summary
Understanding and predicting the interaction between riparian vegetation and river morphology is crucial to assess river evolutionary trajectories under different climate, flow regulation, and river restoration scenarios. In this context, the goal of BASEveg is to quantify important geomorphological processes that so far have been described only in qualitative way. This will be achieved developing a physically-based, quantitative tool integrating both eco-morphological and numerical expertise.  Therefore, BASEveg aims to:
- advance and further develop the vegetation dynamic model to be included in existing two-dimensional models capable of predicting river morphodynamic changes;
- analyse the thresholds between vegetated and un-vegetated bed morphologies, as a function of flood intensity and the ratio between vegetation growth timescale and flood frequency, for different types of vegetation and different initial morphological configurations;
- investigate and modelling the morphological and vegetation dynamics and their interactions in a reach of the highly dynamic braided Tagliamento River in NE Italy, which is worldwide known as an reference river system for the interactions between flow, sediment transport and riparian vegetation dynamics. 
The project will be carried out at the Laboratory of Hydraulic, Hydrology and Glaciology of the ETH Zurich. The proposed model can pave the road to a novel interesting approach, able to provide novel insight into both fundamental and applied research questions in river science.
Direktlink auf Lay Summary Letzte Aktualisierung: 01.09.2015

Verantw. Gesuchsteller/in und weitere Gesuchstellende

Mitarbeitende

Name Institut

Abstract

River managers and a society that aims at a sustainable interaction with the fluvial system are challenged by the need to ensure flood protection, water resources availability, and ecosystem health in a changing environment. Understanding and predicting the interaction between riparian vegetation and river morphology is crucial to assess river evolutionary trajectories under different climate, flow regulation, and river restoration scenarios. In this context, the goal of the project is to quantify important geomorphological processes that so far have been described only in qualitative way. This will be achieved developing a physically-based, quantitative tool integrating both eco-morphological and numerical expertise. The developed model will be a useful tool to assist in the designing and monitoring of multi-objective river restoration and flood protection projects. The starting point of the project is an already available two-dimensional model developed recently by two of the applicants at Laboratory of Hydraulic, Hydrology and Glaciology of the ETH Zurich in collaboration with researchers from the University of Trento (Italy). This model is able to describe the interplay between sediment transport, morphodynamics of rivers and riparian vegetation dynamics. Despite the simplifying hypotheses, the model accounts for the main bio-geomorphological processes involved in the coupled interaction between riverbed morphological evolution and vegetation dynamics and is able to capture the attitude of hydro-geomorphological quantities to set two different equilibrium configurations (vegetated vs. un-vegetated). The research plan is composed of three different tasks that will be performed essentially by a PhD student supported by the supervisors. The overall duration of the project is 36 months.In Task A we improve the vegetation dynamic model already available. The most important subtasks consider the inclusion of the effects of fine material in recruiting a different type of vegetation from the one recruited by the gravels as well as the investigation of different physically based mathematical relations describing the vegetation dynamics. The newly developed model will be tested on different hypothetical cases.In task B we focus on the threshold that identifies the transition between vegetated and un-vegetated river bed configurations. This threshold will be expressed as a function of flood intensity (stream power per unit width) and the ratio between vegetation growth timescale and flood frequency. The tool developed in task A will be used to investigate the dependency of such threshold from different initial conditions, the presence of fine sediments and other model parameters.In task C the temporal evolution of both vegetation and morphology of a selected reach of the braided Tagliamento River will be investigated. This will be done by analysing already available LIDAR data. Then the tool developed in Task A will be used to reproduce the observed ecogeomorphic changes: this will allow us to identify weaknesses and strengths of the proposed model in replicating actual river behaviours, thus providing feedback to improve the novel model components such as the vegetation dynamic module. The proposed research addresses a fast-breaking area of river science to which the applicants has made significant contributions in the last years. Moreover, the proposed model can pave the road to a novel interesting approach, able to provide novel insight into both fundamental and applied research questions in river science.
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