Runoff generation in an intensively disturbed, abandoned farmland catchment, Central Spanish Pyrenees

Abstract

This paper studies the hydrological response to rainstorm events of a small experimental catchment in the Central Spanish Pyrenees. The Arnás catchment was cultivated until 40 years ago, and then abandoned and affected by plant recolonisation, especially shrubs. A rainfall of a few mm is enough to produce a sudden increase in discharge, due most probably to the steep gradients and the small size of the catchment and the extensive areas with low vegetation density and thin soils. The intensity of the response shows a very high variability, depending on the intensity of precipitation and soil humidity conditions before the flood. This paper identifies two types of floods according to the relationships between precipitation and discharge, and confirms that antecedent soil moisture explains much of the response. The shape of the hydrograph, very similar to the hyetograph, suggests that the Arnás catchment is dominated by overland flow processes. However, more intense rainstorms do not generate higher peak flows, thus demonstrating the existence of different runoff generating areas.

Hydrological dynamics in a small catchment with silvopastoral land use in SW Spain

“…The complexity in the generation of runoff was also reported for several drainage basins with Mediterranean mountain climate (Gallart et al, 2002;García Ruiz et al, 2005). Llorens and Gallart (1992) and Gallart et al (1994) already showed that the response of these catchments is largely driven by antecedent conditions, demonstrating that during the year, the dominant runoff generation mechanisms change gradually, as a result of both varying catchment antecedent wetness conditions and changing rainfall event characteristics (Gallart et al, 2005).…”

Catchment based hydrology under post farmland abandonment scenarios

“…Long-term monitoring of these catchments has provided useful hydrogeomorphological information, enabling study of the factors that explain their hydrological and sedimentological responses Seeger et al, 2004;García-Ruiz et al, 2005;Serrano-Muela et al, 2008;Llorente-Adán et al, 2015;Nadal-Romero et al, 2016), their water and sediment sources (González et al 1997;Lana-Renault and Regüés 2009;Butzen et al, 2011;Lana-Renault et al, 2014a), the dynamics of the groundwater table Lana-Renault et al, 2014a), translocation and stemflow processes (SerranoMuela et al, 2012) and the hydrological properties of their soils (Seeger and Ries, 2008;Regüés et al, 2012Regüés et al, , 2017Serrano-Muela et al, 2014). These findings have enhanced knowledge of the runoff generation processes operating in these catchments under different rainfall and moisture conditions , 2014cSerrano-Muela et al, 2008;Nadal-Romero et al, 2016).…”

Modelización espacialmente distribuida de la erosión y el transporte de sedimento en cuencas de montaña del Pirineo aragonés: retos para la calibración y validación

“…Así, se ha estudiado su funcionamiento hidrológico (García-Ruiz et al, 2005;LanaRenault et al, 2007a, b), las propiedades físico-químicas de los suelos (Navas et al, 2002a(Navas et al, , b, 2005Seeger et al, 2004) y los procesos erosión y transporte de sedimentos (Lana-Renault y Regüés, 2007Regüés, , 2009López-Vicente et al, 2011).…”