Temporal distribution of suspended sediment transport in a humid Mediterranean badland area: The Araguás catchment, Central Pyrenees

• Published in: Geomorphology (Amsterdam, Netherlands) Vol. 97; no. 3; pp. 601 - 616
• Main Authors: Nadal-Romero, E., Latron, J., Martí-Bono, C., Regüés, D.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 15.05.2008; Elsevier
• Subjects: Badlands; Central Pyrenees; Earth sciences; Earth, ocean, space; Exact sciences and technology; Geomorphology, landform evolution; Marine and continental quaternary; Mediterranean catchment; Sediment transport; Surficial geology; Suspended sediment concentration; Iberian Peninsula; Southern Europe; Pyrenees; Spanish Pyrenees; Europe; Spain; ASW, Venezuela, Aragua; MED, Western Mediterranean; MED; Suspended sediment concentration; Badlands; Central Pyrenees; Mediterranean catchment; Sediment transport; stream transport; floods; temporal distribution; drainage basins; modern; correlation coefficient; regolith; rainfall; land cover maps; runoff; weathering; concentration; climate; infiltration; erosion rates; badlands; sediment yield; suspended materials; sediment transport; erosion; Mediterranean region; seasonal variations; hydrographs; landform evolution
• ISSN: 0169-555X; 1872-695X
• DOI: 10.1016/j.geomorph.2007.09.009

This paper analyses the temporal patterns of suspended sediment yield in the Araguás catchment, Central Spanish Pyrenees, a small experimental catchment with extensive badlands. The catchment has been monitored since 2004 to study weathering, erosion, and hydrological and sediment responses to understand the superficial dynamics of a badland area in a relatively humid environment. The development of badlands in the Central Spanish Pyrenees is favoured by the presence of marls and a markedly seasonal climate. The continuous observation of selected physical parameters and environmental variables enables us to establish seasonal patterns of weathering processes and identify those factors that control regolith development. Freeze–thaw cycles in winter and wetting–drying in spring–summer are the main processes involved in regolith weathering, thereby controlling slope development in combination with rainfall-related erosion processes. The 64 floods recorded during the study period (December 2005 to January 2007) were used for a hydrosedimentological analysis. The main observed features indicate that the Araguás catchment reacts to all rainfall events, resulting in steep rising and recession limbs on the hydrograph and a very short time lag. Floods show high suspended sediment concentrations and a heterogeneous temporal distribution related to seasonal variations in surface runoff production. These differences increase the degree of complexity involved in studying sediment response. Suspended sediment concentration and transport mainly depend on rainfall volume, maximum rainfall intensity, peak flow, and runoff occurrence. Finally, the similarities among the obtained hydrographs, sedigraphs, and hyetographs, in combination with the rapid response of most of the floods, suggest a large contribution of overland flow, derived mainly from infiltration excess runoff upon badland areas. Accordingly, the significant correlations obtained between rainfall intensity and sediment concentration (mainly during the dry season), which suggest a single source area for both runoff and sediment, also support the hypothesis of Hortonian hydrological response within badland areas.