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ROOT Erosion Dynamics and the Nonlinear Effect of Strenghtening of river alluvial Sediments (ROOTEDNESS)

Gesuchsteller/in Perona Paolo
Nummer 125273
Förderungsinstrument Projektförderung (Abt. I-III)
Forschungseinrichtung Institut d'ingénierie de l'environnement EPFL - ENAC - IIE
Hochschule EPF Lausanne - EPFL
Hauptdisziplin Andere Gebiete der Ingenieurwissenschaften
Beginn/Ende 01.01.2010 - 31.03.2014
Bewilligter Betrag 219'425.00
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Alle Disziplinen (2)

Disziplin
Andere Gebiete der Ingenieurwissenschaften
Hydrologie, Limnologie, Glaziologie

Keywords (10)

Root anchoring; Vegetation uprooting; Root resistance; Flow erosion; Soil cohesion; Sediment reinforcement; Flume experiments; Uprooting experiments; Stochastic modelling; Uprooting mechanisms

Lay Summary (Englisch)

Lead
Lay summary

The interaction between a river and its biotic and abiotic environment is a frontline research topic of ecohydrology and ecohydraulics. In particular, nowadays important open questions concern the role of vegetation roots in locally reinforcing the alluvial sediment (e.g., river bars and gravel islands) on which germination of seedlings or taking roots from woody debris has occurred.The goal of ROOTEDNESS is to increase our process understanding on how river hydrology time scales start interacting with that of vegetation growth and the related roots anchoring ability. We aim at developing a mechanistic knowledge of these processes via extensive well controlled laboratory experiments. We will perform flow ero-sion experiments based on adequate working hypothesis that may reliably simplify the true complexity observed at the real scale. Our experiments will allow for the quantification of time scale(s) ratio required to com-pletely erode and remove a given root system as a function of root structure and age and depending on flow conditions. By means of pullout experiments we will also correlate the force required for static uprooting to the root mechanical anchoring in a quantitative way. We will then consolidate the experimental information into a mechanistic formulation of the root reinforcement mechanisms. This will be done for purely static uprooting and for the erosion induced one in relation to time scales and magnitude of the hydrologic and hydrodynamic perturbations. We will draw on ideas from the fields of mechanics of materials (e.g., metal fatigue) and biome-chanics (e.g., shear-induced hemolysis), to develop a useful and appropriate conceptual and mathematical description. The latter will help describing the feedback between vegetation and sediment dynamics, which is fundamental to the geomorphological evolution of the restoration. The project will be carried out at the Institute of Environmental Engineering of EPFL.This project completes the current research we have been conducting within the projects RECORD (www.record.ethz.ch) and RIVERINE (www.riverine.ethz.ch). Significant advancements in support of the ecohy-drology and fluvial hydraulic communities are expected to provide a pioneering basis for river restoration engineering practice.

Direktlink auf Lay Summary Letzte Aktualisierung: 21.02.2013

Verantw. Gesuchsteller/in und weitere Gesuchstellende

Mitarbeitende

Publikationen

Publikation
Impact of floods on the statistical distribution of riverbed vegetation
(2013), Impact of floods on the statistical distribution of riverbed vegetation, in Geomorphology, 202, 51-58.
Biomass selection by floods and related timescales: Part 1. Experimental observations
(2012), Biomass selection by floods and related timescales: Part 1. Experimental observations, in Advances in Water Resources, 39, 85-96.
Experimental characterization of root anchoring in non-cohesive sediment
(2012), Experimental characterization of root anchoring in non-cohesive sediment, in RIVER FLOW 2012, , IAHR International Conference on fluvial hydraulics, Eds. Murrillo, Costa Rica.
Mechanisms of vegetation uprooting by flow in alluvial non-cohesive sediment
(2011), Mechanisms of vegetation uprooting by flow in alluvial non-cohesive sediment, in HYDROLOGY AND EARTH SYSTEM SCIENCES, 15(5), 1615-1627.
Flow-induced uprooting of young vegetation on river bedforms
, Flow-induced uprooting of young vegetation on river bedforms, in River Flow 2014, Lausanne.
Influence of root characteristics and soil variables on the uprooting mechanics of Avena sativa and Medicago sativa seedlings
, Influence of root characteristics and soil variables on the uprooting mechanics of Avena sativa and Medicago sativa seedlings, in Earth Surface Processes and Landforms.

Zusammenarbeit

Gruppe / Person Land
Formen der Zusammenarbeit
University of Manchester Grossbritannien und Nordirland (Europa)
- vertiefter/weiterführender Austausch von Ansätzen, Methoden oder Resultaten
Politecnico di Torino Italien (Europa)
- vertiefter/weiterführender Austausch von Ansätzen, Methoden oder Resultaten
ETH Zurich Schweiz (Europa)
- Forschungsinfrastrukturen

Wissenschaftliche Veranstaltungen

Aktiver Beitrag

Titel Art des Beitrags Titel des Artikels oder Beitrages Datum Ort Beteiligte Personen
European Geosciences Union (EGU 2014) Poster Experimental implementation of parallel riverbed erosion to study vegetation uprooting by flow 30.04.2014 Vienna, Oesterreich Edmaier Katharina Maria; Perona Paolo;
European Geosciences Union (2014) Poster On the biomechanics of seedling anchorage 30.04.2014 Vienna, Oesterreich Edmaier Katharina Maria; Perona Paolo;
Biohydrology Conference: Bio meets Hydrology Vortrag im Rahmen einer Tagung Resistance to uprooting of Avena sativa and Medicago sativa and related significance for juvenile riverbed vegetation 19.09.2013 Landau, Deutschland Edmaier Katharina Maria; Perona Paolo; Burlando Paolo;
American Geophysical Union (AGU 2012) - Fall meeting Poster Statistical distribution of pioneer vegetation: the role of local stream power. 09.12.2012 San Francisco, Vereinigte Staaten von Amerika Perona Paolo; Edmaier Katharina Maria;
American Geophysical Union (AGU 2012) - Fall meeting Poster Experimental determination of vertical uprooting resistance for grass species used in flume experiments 09.12.2012 San Francisco, Vereinigte Staaten von Amerika Edmaier Katharina Maria; Burlando Paolo; Perona Paolo;
American Geophysical Union (AGU 2012) - Fall meeting Vortrag im Rahmen einer Tagung Above- and below-ground aspects of flow, sediment and vegetation interactions and timescales in alluvial rivers 09.12.2012 San Francisco, Vereinigte Staaten von Amerika Perona Paolo;
RIVER FLOW 2012 - IAHR International Conference on River Hydraulics Vortrag im Rahmen einer Tagung Experimental characterization of root anchoring in non-cohesive sediment. 12.09.2012 -, Costa Rica Edmaier Katharina Maria; Perona Paolo;
IAS 29th Meeting of Sedimentology Vortrag im Rahmen einer Tagung Unravelling vegetation root and fluvial ecomorphodynamic processes and timescales 10.09.2012 Schladming, Oesterreich Perona Paolo;
European Geosciences Union (EGU 2012) Poster Resistance to uprooting of Alfalfa and Avena Sativa and related importance for flume experiments 22.04.2012 Vienna, Oesterreich Burlando Paolo; Edmaier Katharina Maria; Perona Paolo;
European Geosciences Union (EGU 2012) Vortrag im Rahmen einer Tagung Vegetation roots and fluvial ecomorphodynamics: processes and related timescales 22.04.2012 Vienna, Oesterreich Perona Paolo;
Summer School on Earth Surface Dynamics Einzelvortrag River ecomorphodynamics and the role of below ground biomass 08.08.2011 St. Antony Falls, Minneapolis, MN, Vereinigte Staaten von Amerika Perona Paolo;
European Geosciences Union (EGU 2010) Poster Exploring mechanisms of root erosion by flood in laboratory experiment 25.04.2010 Vienna, Oesterreich Perona Paolo; Edmaier Katharina Maria;


Veranstaltungen zum Wissenstransfer

Aktiver Beitrag

Titel Art des Beitrags Titel des Artikels oder Beitrages Datum Ort Beteiligte Personen
Summer Institute on Earth Surface Dynamics 08.08.2011 St. Antony Falls, Minneapolis, MN, Vereinigte Staaten von Amerika


Abstract

The interaction between a river and its biotic and abiotic environment is a frontline research topic at the interface between hydrology, hydraulics and ecology. Recent theoretical, experimental and modelling work has focussed on the active role that riparian vegetation plays in the morphodynamic evolution of rivers, a topic with both scientific and practical implications ranging from basic research to river engineering purposes. The success of riverine corridor management can be assessed by quantifying the effectiveness of the adopted strategies, in particular with respect to ecosystem functioning, biodiversity and water quality. Establishing a mechanistic understanding thereof will affect the trend of future projects focusing at river management strategies and restoration. Besides representing one of the major interest of the scientific community, these studies are also current priorities of Cantonal and Federal agencies (http://www.rhone-thur.eawag.ch/), as well as of Science Foundation Programmes (SNSF 2006) as far as the basic research on the interactions between land and water is concerned. A good example in this respect is given by the research project “RECORD” recently funded by the ETH domain Competence Center on Environment and Sustainability (http://www.cces.ethz.ch). Because of the great number of variables involved in river ecohydraulics and of the limited understanding of their interactions, there is a great deal of uncertainty in the predictions of the effectiveness of river management strategies even for short term horizons. Therefore, there is urgent need to develop a better understanding of the underlying processes. In river engineering an important open question concerns with the role of vegetation roots in locally reinforcing alluvial sediments (e.g., river bars and gravel islands) on which germination has occurred. The survival of early vegetation on river bars and islands and the effect of their root systems in soil matrix stabilization are a key element for the establishment and the maintenance of new ecotones, and therefore control the future evolution trajectory of the riverine environment. In particular, important unresolved questions emerge on how river hydrology time scales leading to inundation processes start interacting with that of vegetation growth (and therefore the related roots anchoring ability), and what type of flow variability increases the chances of survival of a given vegetation type and age. At present, there are not many observations available in literature in this respect, being the classic approach that of investigating root induced stabilization on river banks or watershed slopes. This project intends to initiate increased process understanding by developing a mechanistic knowledge of these processes via extensive well controlled laboratory experiments. The goal of ROOTEDNESS is to investigate the role that local stabilization by vegetation roots of different age and species plays on the time scales of erosion of alluvial sedimentary non-cohesive material. Because of the true complexity existing at the natural scale, basic working hypotheses are needed. Accordingly, targeted laboratory experiments will allow to gain insights about the erosion process in the presence of roots. We will perform flow erosion experiments, which will allow for the quantification of the time scale(s) required to completely erode and remove a given root system as a function of root structure and age and depending on flow conditions. In parallel experiments vegetation stems will be cut at the ground level thus limiting the influence of the vegetation on the bed shear stress and removing the drag action of the stream on the plant biomass. This will allow quantification of the relative contributions to stabilization/destabilization by roots and erosion processes. By means of pullout experiments we will also correlate the force required for static uprooting to the root mechanical anchoring in a quantitative way. We will then consolidate the experimental information into a mechanistic formulation of the root reinforcement mechanisms. This will be done for purely static uprooting and for the erosion induced one in relation to time scales and magnitude of the hydrologic and hydrodynamic perturbations. We will draw on ideas from the fields of mechanics of materials (e.g., metal fatigue) and biomechanics (e.g., shear-induced hemolysis), to develop a useful and appropriate conceptual and mathematical description. The latter will also quantify the feedback between vegetation and sediment dynamics, which is fundamental to the geomorphological evolution of the restoration. The project workplan is divided into 3 years. Research will be carried out at the Chair of Hydrology and Water Resources Management of the Institute of Environmental Engineering of ETH Zurich (IfU-ETHZ) as far as the erosion experiments are concerned, with the support of scientists based at WSL, EPFL, Politecnico di Torino (Turin, Italy) and King’s College London. In summary, the scientific value of this project is twofold. First, it will provide significant knowledge advancements in understanding the erosion dynamics time scales of non-cohesive sediments reinforced by roots, which are typical of river bed and bars. Second, the harmonized use of laboratory experiments allows a unique coordinated investigation and a comprehensive vision of the problem to support the ecohydrology and fluvial hydraulic communities, and also providing a pioneering basis for river restoration engineering practice.
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