Testing simple approaches to map sediment mobilisation hotspots after wildfires

Abstract

Background: The models currently used to predict post-fire soil erosion risks are limited by high data demands and long computation times. An alternative is to map the potential hydrological and sediment connectivity using indices to express the general properties of the burnt landscape. Aims: In this study, we aimed to answer the question: Do these tools identify post-fire sediment mobilisation hotspots? Methods: To achieve this, we assessed the spatial variability distribution of the location of soil erosion hotspots using the Index of Connectivity, Revised Universal Soil Loss Equation and the Sediment Export, and compared it with the simulation results of a more complex Landscape Evolution Model (LAPSUS model). Additionally, we evaluated statistical measures of association between the four tools. Key results: The three tools tested in this study are suitable for identifying sediment mobilisation hotspots, where the erosion rates are above the 95th percentile, and differences between their performance are small. Conclusions: The results indicate that these tools help locate extreme erosion locations in recently burnt areas. Implications: These results can be considered for post-fire and water contamination risk management, especially for fast prioritisation of areas needing emergency post-fire intervention.