Flood events in Mediterranean ephemeral streams (ramblas) in Valencia region, Spain

This article deals with flood events in Mediterranean ephemeral streams typ ical of the Valencia region. The combination of the basin physical characte ristics (steep slopes, sparse vegetation, thin soils and permeable rock) an d intense, heavy and irregularly distributed rain, generates flash floods. Runoff generation is sudden, giving rise to flash floods with sharp, narrow hydrographs with short time lags. The high amount of runoff is, neverthele ss, only a small fraction of the total rainfall, since the characteristics of the river basins are such that infiltration of large amounts of water oc curs. Using daily hydrological data from the Rambla de la Viuda basin and 5 -min data from both the Barranc del Carraixet and the Rambla de Poyo basins , the rainfall-runoff processes have been analysed during flood events in t hese ephemeral streams. (C) 2001 Elsevier Science B.V. All rights reserved.