Hydrological and erosional response of a small catchment in Sicily

Increasing our understanding of the main processes acting in small Mediterranean catchments is essential to planning effective soil and water conservation practices in semi-arid areas. A monitoring program of a Sicilian catchment started in 1996 and ended in 2006. The factors driving the hydrological response for 170 events with runoff generation and 46 with sediment production were specified. The catchment response varied greatly over the year. Rainfall intensity was a poor driver of runoff generation, whereas both the simulations made with the Thornthwaite-Mather water balance model and hydrograph recession analyses, pointed to the chief importance of wet antecedent conditions and soil saturation processes in runoff generation. The influence of rainfall spatial variability was also examined. SSC-Q relationships, classified by following their shapes for all sediment production events, suggested that the principal role of small poorly vegetated hillslope patches was as sediment sources and confirmed the complexity of the hydrological response in this small Mediterranean catchment.