Gully erosion is a significant geo-hydrological phenomenon occurring worldwide. Such phenomena contribute significantly to the soil erosion on a catchment and to its morphological shaping. In so doing, it impacts all the processes acting in a hillslope. Being one of the principal processes of soil erosion, gully erosion will play an important role in worsening the effects of climate and land use changes in the near future. Therefore, the prediction of the spatial and temporal occurrence of these phenomena is an interesting problem both for the scientific world and more in general for the society. In this work we model gully erosion on different study areas, using a distributed pixel-based model. The LANDPLANER model was used for the purpose, mainly due to its ability to deal with scenario-based analysis and due to the limited requirements of input data in its basic configuration, which include a DEM and a land cover map to derive the parameters of the runoff through the Curve Nuumber method. The twofold erosion modelling schema integrated in LANDPLANER, namely a quasi-static topographic threshold approach and a dynamic simplified erosion index, were tested in some study areas, considering the local morphological, climatological and Land Use/Land Cover conditions. We propose a framework to derive such dynamical model input data to better characterize the spatial and temporal occurrence of gully phenomena. Open source (SENTINEL-2) and commercial satellite (WorldView 3) data are used for the purpose and with the main objectives to perform long term, seasonal, event and scenario-based modelling analyses. Modelling results were validated using geomorphological and gully phenomena inventories, using different spatial criteria and different performance metrics. We maintain that the tested modelling and validation approaches can be easily replicated and applied in other different study areas to better characterize the spatial and temporal occurrence of gully erosion phenomena.
Dynamic distributed gully erosion modelling and validation
Mauro Rossi;Margherita Agostini;Dino Torri
2019
Abstract
Gully erosion is a significant geo-hydrological phenomenon occurring worldwide. Such phenomena contribute significantly to the soil erosion on a catchment and to its morphological shaping. In so doing, it impacts all the processes acting in a hillslope. Being one of the principal processes of soil erosion, gully erosion will play an important role in worsening the effects of climate and land use changes in the near future. Therefore, the prediction of the spatial and temporal occurrence of these phenomena is an interesting problem both for the scientific world and more in general for the society. In this work we model gully erosion on different study areas, using a distributed pixel-based model. The LANDPLANER model was used for the purpose, mainly due to its ability to deal with scenario-based analysis and due to the limited requirements of input data in its basic configuration, which include a DEM and a land cover map to derive the parameters of the runoff through the Curve Nuumber method. The twofold erosion modelling schema integrated in LANDPLANER, namely a quasi-static topographic threshold approach and a dynamic simplified erosion index, were tested in some study areas, considering the local morphological, climatological and Land Use/Land Cover conditions. We propose a framework to derive such dynamical model input data to better characterize the spatial and temporal occurrence of gully phenomena. Open source (SENTINEL-2) and commercial satellite (WorldView 3) data are used for the purpose and with the main objectives to perform long term, seasonal, event and scenario-based modelling analyses. Modelling results were validated using geomorphological and gully phenomena inventories, using different spatial criteria and different performance metrics. We maintain that the tested modelling and validation approaches can be easily replicated and applied in other different study areas to better characterize the spatial and temporal occurrence of gully erosion phenomena.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.