摘要
Hydrological effects of forest fires have been extensively studied with main emphasis on floods, whereas streamflow at coarse temporal scales (e.g., monthly) has generally drawn less attention. Yet, accounting for changes after fires, until the return to pre-fire conditions, is vital in water resources management. This paper presents a study on the hydrological effect of hypothetical forest fires in a Mediterranean basin, the Enipeas river basin (439 km2) in Thessaly, Greece. The water balance of the basin is assessed for pre-fire conditions and after hypothetical fire events. For this, the hydrological model SWAT (Soil and Water Assessment Tool) is used, which allows for reliable predictions of runoff and other water balance components. For post-fire conditions, knowledge from earlier studies is exploited so as to modify key model parameters, such as the Curve Number of the well-known SCS-CN method. The daily temporal scale is employed, which is sufficiently fine to allow for accurate representation of the physical processes. Monthly discharge data are used for model calibration and validation. Three fire scenarios are formulated, based on known features of fires in the Mediterranean region for similar topography and land uses. The following effects of forest fires are quantified: (1) changes in mean values of the total runoff and runoff components on the monthly, three-month, six-month and annual basis; and (2) the effect on hydrological drought classification through using a drought index known as the Streamflow Drought Index (SDI). Keywords Forest fires Streamflow SWAT Thessaly Drought Streamflow Drought Index (SDI)