Instream Wood

On The October 8, 2021

9h - 12h
Webinar in French and English

Within a partnership between Univ. of Lausanne and the University of Lyon (EUR H2O’Lyon) and other universities (e.g., IHE Delft, Ecole des Mines of Saint Etienne), some of our researchers have been working in Génissiat during the last 15 years, on dynamics of instream wood, exploring wood sources within the catchment, notably the sub-basins of the Arve and the Valserine.

Speakers :

  • Hervé Piégay // Short introduction about the wood studies in Génissiat.
  • Virginia Ruiz-Villanueva // Wood flux and origin in Génissiat.
  • Javier Del Hoyo // New methods to detect the origin of Wood.
  • Capucine Dupont // Conversion of river driftwood into added-value products.
  • Hossein Ghaffarian // Videomonitoring of wood.

"Several master and phd thesis have been developed there. Génissiat dam (Barrage de Génissiat, near the village of Injoux-Génissiat, ~50 km downstream from Geneva) offers us an unique site to study different processes related to the instream wood. All the wood arriving to the reservoir is retained and must be extracted by the Compagnie Nationale du Rhône (CNR), so we can analyze the amount of wood, its sources, the relation to floods, etc.. All relevant aspects for the dam safety, river and flood risk management.
All this gained knowledge has been published in scientific papers and presented at several international conferences. Now, we would like to disseminate our main findings to stakeholders and managers (related to Génissiat and elsewhere), in order to discuss the results, to identify major unsolved issues and define our next challenges.

Specific work has been also done on the conversion of river driftwood into added-value products. The most straightforward use of river driftwood can be its combustion to produce heat and power. However, other value chains could be imagined leading to higher added-value products, such as the thermal conversion of river driftwood via pyrolysis or hydrothermal carbonization into biochar, a carbon-rich and porous material. The material properties can be tailored for various uses, among which soil improving material in agriculture, adsorbent for water or gas pollutants, and electrode in batteries for energy storage. We have recently explored in particular this latter option, and successfully operated sodium-ion batteries with driftwood-based anodes. The results showed excellent electrochemical performances, meaning that the driftwood-based anodes can compete with commercial materials, usually fossil-based and very expensive. In addition, the estimations of the river driftwood available suggest that it would be possible to supply large battery factories with this bio-based material.

We believe dam managers and stakeholders in both France and Switzerland share similar concerns about instream wood and we would like to learn more about experiences and strategies in other sites. In addition, we aim at showing the relevant data we can extract from the transported wood and how to use it to inform river management."