A proposed method for modelling the hydrologic response of catchments to burning with the use of remote sensing and GIS

Abstract Forest fires can have significant effects on the hydrological response of catchments, resulting in many cases in severe land degradation, flooding and soil erosion. These post-fire hazards often cause extensive damage to public and private property and urban infrastructure, thus carefully planned and designed mitigation activities are required for reducing their magnitude. This study presents a method for the quantitative estimation and mapping of post-fire erosion and runoff, which can provide the basis for the planning of these mitigation activities. Within the context of the proposed method a soil-erosion model is integrated within a GIS and remote sensing and digital cartographic data are used for estimating the model parameters before and after the passage of the fire. The model incorporates the effects of fire on the parameters that control erosion using remotely sensed estimates of the characteristics of the fire, such as the temperature and the extent. The method was implemented in four regions in Greece where severe wildfires took place during the summer of 1998. Pre- and post-fire model runs showed significant changes in runoff and erosion patterns as a result of the passage of the fire and a notable increase in the spatial variability of post-fire erosion rates. Results indicated net increases of up to 0.76 × 10 − 2  mm/h in erosion rates, although small decreases were also observed in some areas. The application of the method led to the identification of areas where erosion is expected to accelerate significantly and thus hazard-mitigation works are urgently required. The proposed method can clearly benefit from higher resolution remote-sensing data and more detailed datasets on soil properties and characteristics and is expected to provide a useful tool in planning and prioritising the works that are required for the mitigation of post-fire hazards.