Metals discharged during different flow conditions from a mixed agricultural‐forest catchment (NW Spain)

• Published in: Hydrological processes 2015-03, Vol.29 (6), p.1644-1655
• Main Authors: Soto‐Varela, F, Rodríguez‐Blanco, M. L, Taboada‐Castro, M. M, Taboada‐Castro, M. T
• Format: Article
• Language: English
• Subjects: aluminum; base flow; copper; headwater stream; hydrological parameters; iron; manganese; metal loads; rain; runoff; rural catchment; streams; temporal variability; watersheds; zinc
• ISSN: 0885-6087; 1099-1085
• DOI: 10.1002/hyp.10282

Metal loads were determined from water samples collected under different streamflow conditions (baseflow and storm events) in a rural catchment (NW Spain) during 4 years. A study at annual, seasonal and storm‐event scales was carried out. In all analysed scales, the export order was Fe > Al > Mn > Zn > Cu. A high inter‐annual, seasonal and storm‐event scale variability of metal load was observed. The total metal loads in stream were higher during baseflow conditions than during storm events, which only represented 4% of the duration of the study period and 25% of streamflow. During storm events, both Al and Fe loads accounted 45% of the total load of the study period, whereas Mn, Cu and Zn loads represented 42%, 33% and 24%, respectively. This highlights the role of high flows on metal export. Only four big events exported around 30% of load of each metal transported in events. At all time scales, a prevalence of export of particulate metals over dissolved metals was observed, more pronounced for Al, Fe and Mn than for Cu and Zn. The export of metals in the Corbeira catchment is influenced by runoff and, to a lesser extent, by the rainfall amount. Copyright © 2014 John Wiley & Sons, Ltd.