Hydrological response in a forested cathment of the Pyrenees : the case of San Salvador

Abstract

This paper studies the main hydrological characteristics of the San Salvador experimental catchment, a representative area in the middle mountain of the Pyrenees, scarcely affected by human activities. The basin is characterized by the presence of a dense forest cover that conditions the hydrological response against any rainstorm event. The San Salvador catchment has been monitored since 1999 by means of a gauging station and a weather station, to quantify the runoff and sediment yield. 40 floods have been considered for the study, between September, 1999 and June, 2005. They have been used to analyse the principal hydrological patterns of the catchment and to rank the factors that better explain the hydrological response. The results show the existence of differences in comparison with environments much more affected by human disturbances, especially due to the importance of antecedent wetness conditions. The intensity and volume of rainfalls have a no relevant role to explain the characteristics of the hydrological response.