Sediment mobility and connectivity in a catchment: A new mapping approach.

Area of Science:

• Earth Science
• Hydrology
• Geomorphology

Background:

• Sediment connectivity is crucial for understanding fluvial channel dynamics.
• Existing methods for quantifying sediment connectivity face ongoing debate and require refinement.
• A novel approach is needed to integrate structural and functional aspects of sediment connectivity.

Purpose of the Study:

• To introduce a new Sediment Flow Connectivity Index (SCI) for fluvial basin analysis.
• To develop a sediment connectivity map applicable to monitoring and management.
• To assess the performance of the SCI in predicting sediment deposit locations.

Main Methods:

• The SCI is calculated using gradient-based flow accumulation of a sediment mobility index.
• The sediment mobility index incorporates rainfall, soil geotechnical properties, and land use data.
• The method was applied to the Vernazza basin, Italy, and compared with the Cavalli et al. (2013) connectivity index (IC).

Main Results:

• The SCI successfully predicted sediment deposit positions and accumulation paths following a 2011 flood event.
• The SCI demonstrated comparable quantitative performance to the IC, with improved qualitative identification of subtle sediment flow paths.
• The study produced a sediment connectivity map for the Vernazza basin.

Conclusions:

• The developed SCI offers a valuable tool for sediment connectivity assessment in fluvial basins.
• The SCI shows potential for application in larger-scale assessments due to the availability of open global datasets.
• Further research is needed to address upscaling and standardization for broader application of the SCI.