Lab

Geomorphology and Nat. Haz at GIUB and RivES-Research Group at UNIL


About the lab

Website: https://wp.unil.ch/rives/

Featured research (1)

Floods impact river morphology in several ways, i.e., lateral shift of the channel (i.e., avulsions), changes in bars spatial distribution (Rusnák & Lehotské, 2014), channel widening (Ruiz-Villanueva et al., 2023), and localized erosion and deposition. These morphological changes may benefit aquatic and riparian ecology, as they create and sustain heterogeneous and diverse habitats (Stanford et al., 2005), but can lead to long-term negative impacts. For instance, lateral shifts of river channels can cause damages to nearby infrastructure, properties and flood protection structures (Environmental Agency, 2018). Additionally, flood-induced morphological changes can also alter channel conveyance capacity, thereby affecting flood hazard (Todd-Burley et al., 2021). Therefore, understanding the rivers´ response to floods is critical for understanding fluvial dynamics and assessing potential hazards and risks. Still, predicting these changes remains challenging. The current study aims to understand and quantify the major geomorphological changes after floods in a partially regulated alpine River, the Spöl River (Graubünden). The flow of the River Spöl is regulated by two dams, Punt dal Gall and Ova Spin. As part of a river restoration program, experimental floods are released from these dams once or twice annually, creating a unique opportunity to study and analyse river morphological changes in a natural laboratory setting (Consoli et al., 2022). Our study site is located in the lower part of the river, downstream from Ova Spin and until the confluence with the Inn River. In this river segment, the Spöl receives flow and sediment from unregulated tributaries. To quantify the geomorphic changes following a sequence of floods, in terms of sediment erosion and deposition and changes in morphology, we used high-resolution digital surface models (DSMs) obtained by structure from motion based on drone-acquired data. The Geomorphic Change Detection (GCD) 7.5.0 standalone software was used to examine the geomorphic changes between the Digital surface Models collected before and after floods since 2018. The preliminary analysis revealed several flood-related morphological changes, stressing areas affected by significant erosion in the uppermost reach, and a general depositional pattern in the downstream part. In addition, we explored changes between the experimental floods, to analyse the effect of the unregulated tributaries input. The current study represents a unique opportunity to explore and quantify geomorphic changes after sequential floods. And, in addition, the study findings will be useful to inform flood and river management.

Lab head

Virginia Ruiz-Villanueva
Department
  • Institute of Geography
About Virginia Ruiz-Villanueva
  • Flood hazard and risk | Cascade processes | Flood dynamics | Fluvial Geomorphology | River Science | Biogeomorphodynamics | Ecomorphology | Riparian vegetation and instream large wood |

Members (9)

Mauro Fischer
  • University of Bern
Llanos Valera Prieto
  • University of Barcelona
Gabriele Consoli
  • Fondazione Edmund Mach - Istituto Agrario San Michele All'Adige
Bryce Finch
  • University of Lausanne
Javier Gibaja del Hoyo
  • University of Lausanne
Maha Sheikh
  • University of Bern
Francis Bangnira
  • University of Surrey
Julia Walker
  • University of Lausanne
Thomas Krieger
Thomas Krieger
  • Not confirmed yet
Marc O´Callaghan
Marc O´Callaghan
  • Not confirmed yet

Alumni (6)

Aldo Fornari
  • University of Lausanne
Christophe Reymond
  • University of Lausanne
Jérémy Marchesseau
  • Institut National des Sciences Appliquées de Lyon