Erosión y desertificación.-Evolución y procesos de erosión en gullies. Bardenas Reales (Navarra). España

Abstract

ABSTRACT At the Bardenas Reales site, gullies are developed over Holocene silts and show a great extend. The most typical features is the lack of relief and the presence of many low and narrow gullies, on which the sidewalls are affected by piping and incision processes. Gullies have a U-shape section and a dendritic pattern with a high sinuosity. Gullies evolution responds to different processes like headcut retreat, scouring, undermining and piping. One of these minor order gullies has evolved from a man made ditch builded in 1997. This ditch acts a as drainpipe of the erosion plot BD1.The main processes was headcut retreat from the outlet point in the main gully, and the deepening and widening of the ditch bottom level. As a consequence of undermining and piping the ditch shows an enlargement and headcut retreat that evolve in an unusual speed in comparison with the environment, that let us to stablish a temporal sequence of the gully evolution in these areas.