000197671 001__ 197671
000197671 005__ 20190118052828.0
000197671 037__ $$aPOST_TALK
000197671 245__ $$aVegetation establishment in convectively accelerated streams
000197671 269__ $$a2013
000197671 260__ $$c2013
000197671 336__ $$aPosters
000197671 520__ $$aWe study the conditions for vegetation establishment within river reaches with converging boundaries. Common to many such rivers worldwide is the existence of a limiting front (e.g., Figure 1a) beyond which all the riverbed vegetation is uprooted by flooding events. There are however exceptions, which leads to an interesting ecomorphodynamic problem (existence and position of the front). We use a theoretical 1-D framework based on morphodynamic equations modified in order to account for the presence of vegetation (Perona et al., submitted), and obtain the link between the position of the vegetated front and river eco-hydraulic variables under steady and unsteady conditions. We apply our framework to a number of flume experiments (unsteady flow) where Avena sativa L. (common oat) seedlings grow subject to periodic flow disturbances within a convergent flume channel (Figure 1b). We find that depending on the outcome of the competition between hydrological and biological processes there is either a limiting spatial front within the convergent section beyond which vegetation cannot survive, or vegetation colonizes the entire riverbed. The existence and the position of the front depend on the ability for vegetation to take root efficiently and withstand uprooting by the flow of the convectively accelerated stream (Crouzy et al., in press). The active role of vegetation and of unit streampower in this particular ecomorphodynamic process are then discussed in relation to the conceptual model of Gurnell and Petts (2006), and under the light of our theoretical and experimental results. REFERENCES - Crouzy, B., K. Edmaier, N. Pasquale and P. Perona (in press). Impact of floods on the statistical distribution of riverbed vegetation. Geomorphology doi:10.1016/j.geomorph.2012.09.013. - Gurnell A., Petts G. (2006). Trees as riparian engineers: The Tagliamento River, Italy. Earth Surface Processes and Landforms, 31: 1558--1574. - Perona, P., B. Crouzy, S. Mc Lelland, P. Molnar and C. Camporeale. Ecomorphodynamics of rivers with converging boundaries. Earth Surface Processes and Landforms, submitted.
000197671 700__ $$0246346$$g137873$$aCrouzy, Benoît
000197671 700__ $$aMcLelland, Stuart
000197671 700__ $$aMolnar, Peter
000197671 700__ $$aCamporeale, Carlo
000197671 700__ $$aPerona, Paolo$$g174097$$0243964
000197671 7112_ $$cSan Francisco, CA, USA$$aAGU Fall Meeting
000197671 909C0 $$0252285$$pAHEAD$$xUS08552
000197671 909CO $$pposter$$ooai:infoscience.tind.io:197671
000197671 917Z8 $$x174097
000197671 937__ $$aEPFL-POSTER-197671
000197671 973__ $$aEPFL
000197671 980__ $$aPOSTER