Resumen de Reconstrucción de la frecuencia de corrientes de derrubios en el Barranco de Erill (Lleida)
Carles Raimat Quintana, Marcel Hürlimann Ziegler, Jordi Corominas i Dulcet, Roberto Jesús Luis Fonseca, Jose Moya Sánchez
The Barranco de Erill, Central Pyrenees has an important thickness of glacial deposits from the last ice ages hold up over igneous and metamorphic materials with instability trend, like debris flow, associated with rainy episodes that conditioned the use of the territory until present time. In the Erill basin we carried out a complex documentary study that included an inquiry of population, the analysis of photo documentation (1912-2011) and the study of daily rainfall records since 1928. Additionally in 2011 the excavation of two trenches on the alluvial fan allowed to measure the thickness of the 20th century events. The results of all these tasks revealed a map of all the episodes that occurred in the area during 20th century, involving events of volumes more than 150.000 m3. In addition, during the last 5 years an exhaustive monitoring regarding the dynamics of the basin and its processes allowed the record of minor hyper concentrated flow events. The combined analysis of contrasting historical data, stratigraphy and geomorphology as well as the monitoring allowed establishing a preliminary magnitude-frequency debris flow curve for this basin.
