Original paper

Sediment balance in four catchments with different land cover in the Central Spanish Pyrenees

Nadal-Romero, Estela; Lana-Renault, Noemí; Serrano-Muela, Pilar; Regüés, David; Alvera, Bernardo; García-Ruiz, José M.

Abstract

In the present study, the sediment output from four monitored experimental catchments in the Central Spanish Pyrenees was investigated. Three of the catchments are located in the middle mountain and have a sub-Mediterranean climate. The San Salvador catchment is covered by dense forest; the Arnás catchment was cultivated until 50 years ago, at which time it was abandoned and subsequently densely recolonized by shrubs and trees; and the Araguás catchment was affected by intense degradation processes that resulted in the development of an active badland area in the lower part. The fourth catchment (the Izas catchment) is located in a high mountain area affected by snow accumulation and melting processes. The results of the study indicate the importance of land use/land cover changes attributable to human activities. The San Salvador catchment had the lowest sediment output, which was dominated by solutes. In the Arnás catchment, plant recolonization after farmland abandonment has resulted in a reduction in sediment sources and hydrological functionality close to forest environments. Nevertheless, the relative importance of bedload in this catchment suggests torrentiality resulting from hillslope cultivation and overgrazing. The Araguás catchment had very high values of suspended sediment, consistent with intense weathering and erosion processes typical of subhumid badland areas. The presence of a long-lasting snow pack in the Izas catchment determined the distribution of each type of sediment throughout the year, with low sediment outputs in winter, high solute and low suspended sediment transport in spring, and high suspended sediment and bedload transport in summer and autumn.

Keywords

sediment balanceland covercentral spanish pyrenees