Estimating Erosion on Two Mediterranean Watersheds of Different Hydrological Regimes

Erosion constitutes one of the major threats for the sustainability of the agricultural sector, since it is considered to be one of the most significant soil degradation processes. This is more critical for the Mediterranean region, since the combination of climate/topographic/soil characteristics and anthropogenic activities are developing high runoff potential. This is expected to be increased since climate change signal indicates rainfall decrease, but also increment in the magnitude and frequency of rainfall extremes, thus potentially increasing erosion. Considering the above, the present study aims to quantify erosion in two Mediterranean watersheds located in Crete Island (south Greece) using the widely applied Universal Soil Loss Equation (USLE) approach. Despite the fact that the two watersheds are located in the same island, they present differences mainly in rainfall amount and geomorphology. With regard to average annual erosion in the agricultural areas of the two watersheds, it was found to be much higher for the western watershed (20.5 t/(ha year)) compared to the eastern watershed (12.5 t/(ha year)). This is mainly attributed to the higher rainfall amount received in the western watershed. The spatial distribution of average annual erosion rates indicate that olive groves, which are dominant for both watersheds, present relatively increased values, thus triggering the necessity for adaptation of cultivation practices in order to avoid further deterioration of soils in the area under climate change.