Multiple temporal scales assessment in the hydrological response of small Mediterranean-climate catchments

Abstract

Mediterranean-climate catchments are characterized by significant spatial and temporal hydrological variability caused by the interaction of natural as well human-induced abiotic and biotic factors. This study investigates the non-linearity rainfall-runoff relationship at multiple temporal scales in representative small Mediterranean-climate catchments (i.e., < 10 km2) to achieve a better understanding of their hydrological response. Rainfall-runoff relationship was evaluated in 43 catchments at annual and event -203 events in 12 of these 43 catchments- scales. A linear rainfall-runoff relation was observed at annual scale with higher scatter in pervious (R2: 0.47) than impervious catchments (R2: 0.82). Larger scattering was observed at event scale, although pervious lithology and agricultural land use promoted significant rainfall-runoff linear relations in winter and spring. These relationships were particularly analysed during five hydrological years in Es Fangar catchment (3.35 km2; Mallorca, Spain) as a temporal downscaling to assess intra-annual variability elucidating that antecedent wetness conditions played a significant role in runoff generation. The assessment of rainfall-runoff relationship under contrasted lithology, land use and seasonality is a useful approach to improve hydrological modelling of global change scenarios in small catchments where linearity and non-linearity of the hydrological response -at multiple temporal scales- can inherently co-exist in Mediterranean-climate catchments.