Improving the Channel Network Management After a Large Infrequent Disturbance, Taking Advantage of Sediment Connectivity Analysis

Abstract

Chile is frequently affected by different natural hazards that are constantly reshaping the landscape. Particularly, Large and Infrequent Disturbances (LIDs) such as wildfires and volcanic eruptions are capable of affecting entire river catchments by altering the hydrological cycle, reducing the land cover, and boosting sediment remobilization. Given the multitude of effects caused by such disturbances, the response of the catchments is not easily predictable, and different geomorphic responses are expected. The assessment of sediment connectivity can help to better comprehend the overall effects of wildfires and volcanic eruptions on the sediment transfer dynamics at the catchment scale. Sediment connectivity infers the potential transfer of sediment between compartments of the catchment according to the spatial configurations and the processes of such compartments. After a LID, awareness of the degree of linkage between sediment sources and downstream areas is pivotal to reduce the risk and hazard, improving catchment management. In Chile, analysis of sediment connectivity is extremely valuable even tough the availability of high-resolution topographic data and catchments’ accessibility are not always guaranteed. For this reason, much effort should be employed to adapt approaches, based on high-resolution data, to this context by exploiting freely available global data and satellite images and to find trade-offs between data requirements and reliability of the outcomes.