Modelling forest fires hydrological impact using spatio - temporal geographical data

In recent years, forest fires frequency and intensity has increased, causing a new awareness about their impact not only on vegetation, but also on hydrological regime. Changes in vegetation influence the processes of interception and evapotranspiration, seriously affecting the hydrological cycle. Forest fires can also affect hydrological processes indirectly, altering the hydraulic properties of the soil. The period needed for the hydrological process recovery is greatly dependent on the rate of vegetation recovery. In dry areas, water shortages can seriously limit this rate. The interaction between hydrological processes and vegetation recovery makes harder the simulation of forest fires hydrological impacts and post-fire recovery with hydrological models, which are not able to consider the significant temporal variability of soil hydraulic properties and vegetation development. This paper presents the modelling of forest fires hydrological impact with a modified hydrological model, using spatio-temporal geographical data. This model can simulate the hydrological balance, taking into account both the spatial and temporal variability of vegetation and soil hydraulic properties. The interactions between hydrological balance, plants water stress, vegetation development, and soil hydraulic properties, can also be simulated within the model. The case study of a Mediterranean experimental watershed in Greece, which was affected by a wildfire in August 2009, is also presented.