Effect of runoff on suspended sediment and phosphorus loading in a headwater stream of a rural catchment (NW Spain)

Abstract

This work examines the suspended sedi­ment (SS) and phosphorus (P) load during rainfall-runoff events in a headwater stream which drains a rural catchment located in Galicia (NW Spain). Another objective is to know the major sources of SS and P ex­ported. Important differences in the SS and P load between events were found, which is associated with the runoff volume, as well as to develop of rills and ephemeral gullies in cultivated fields well connected to the drainage network. The SS load ranged be­tween 0.8 and 21.0 t, while the P load varied between 2.5 and 20.0 kg. The particulate phosphorus (PP) showed significant rela­tionship with SS, which indicates the ero­sive origin of P, especially considering that PP means more 80% of P exported each event.