Unravelling past flash flood activity in a forested mountain catchment of the Spanish Central System

• Published in: Journal of Hydrology
• Main Authors: Ballesteros-Cánovas, Juan A., Rodríguez-Morata, Clara, Garófano-Gómez, Virginia, Rubiales, Juan M., Sánchez-Salguero, Raúl, Stoffel, Markus
• Other Authors: Universitat Politècnica de València. Instituto de Investigación para la Gestión Integral de Zonas Costeras - Institut d'Investigació per a la Gestió Integral de Zones Costaneres, Ministerio de Ciencia e Innovación, Organismo Autónomo de Parques Nacionales
• Format: Article in Journal/Newspaper
• Language: English
• Published: Elsevier 2015
• Subjects: Paleohydrology; Flash flood; Tree ring; Dendrogeomorphology; Hydrometeorological triggers; Sierra de Guadarrama; Borga; North Atlantic; North Atlantic oscillation
• Online Access: http://hdl.handle.net/10251/187397; https://doi.org/10.1016/j.jhydrol.2014.11.027

[EN] Flash floods represent one of the most common natural hazards in mountain catchments, and are frequent in Mediterranean environments. As a result of the widespread lack of reliable data on past events, the understanding of their spatio-temporal occurrence and their climatic triggers remains rather limited. Here, we present a dendrogeomorphic reconstruction of past flash flood activity in the Arroyo de los Puentes stream (Sierra de Guadarrama, Spanish Central System). We analyze a total of 287 increment cores from 178 disturbed Scots pine trees (Pinus sylvestris L.) which yielded indications on 212 growth disturbances related to past flash flood impact. In combination with local archives, meteorological data, annual forest management records and highly-resolved terrestrial data (i.e., LiDAR data and aerial imagery), the dendrogeomorphic time series allowed dating 25 flash floods over the last three centuries, with a major event leaving an intense geomorphic footprint throughout the catchment in 1936. The analysis of meteorological records suggests that the rainfall thresholds of flash floods vary with the seasonality of events. Dated flash floods in the 20th century were primarily related with synoptic troughs owing to the arrival of air masses from north and west on the Iberian Peninsula during negative indices of the North Atlantic Oscillation. The results of this study contribute considerably to a better understanding of hazards related with hydrogeomorphic processes in central Spain in general and in the Sierra de Guadarrama National Park in particular. This study has been partially funded by the projects IDEA-GesPPNN-163/2010 (OAPN - Organismo Autonomo de Parques Nacionales, Ministerio de Agricultura, Alimentacion y Medio Ambiente) and CGL2010-19274 (projects MAS Dendro-Avenidas) of the Spanish Ministry of Economy and Competitiveness. The authors sincerely acknowledge Marco Borga and other anonymous reviewer. Special recognition must be given to CENEAM, Montes de Valsain, OAPN and JCyL for providing ...