Browsing by Subject "piping"

Now showing 1 - 3 of 3
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    Erosión y desertificación.-Evolución y procesos de erosión en gullies. Bardenas Reales (Navarra). España
    Desir, G.; Marín, C.; Universidad de Murcia
    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.
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    Erosión y desertificación.-Pinhole test for identifying susceptibility of soils to piping erosion: effect of water quality and hydraulic head
    Nadal Romero, E.; Verachtert, E.; Poesen, J.; Universidad de Murcia
    ABSTRACT Piping has been observed in both natural and anthropogenic landscapes, in different climates, lithologies and soils, as well as under different types of land uses and vegetation covers. Despite its importance, no standard widely-applied methodology exists to assess susceptibility of soils to piping. This study aims at evaluating the pinhole test for assessing the susceptibility of soils to piping under different conditions. More precisely, the effects of hydraulic head and water quality are being assessed. Topsoil samples (remoulded specimens) with a small range of water contents were taken in Central Belgium (Heverlee) and the susceptibility of these soil samples are investigated under standardized laboratory conditions with a pinhole test device. Three hydraulic heads (50, 180 and 380 mm) and two water qualities (tap and distilled water) were used, reflecting dominant field conditions. The results indicate significant differences between different hydraulic heads and water qualities. Maximum flow discharge was recorded at 380 mm, showing small differences between tap and distilled water. Maximum sediment discharges were recorded at 380 mm and significant higher sediment discharges were observed for distilled water compared to tap water. The tests indicate that the tested soil has an intermediate susceptibility to piping.
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    Erosión y desertificación.-Procesos de erosión actuantes en una zona de clima semiárido de la Depresión del Ebro (Bardenas Reales, NE de España)
    Marín, C.; Desir, G.; Universidad de Murcia
    ABSTRACT Bardenas Reales is an erosive depression located in the central-western part of the Ebro Depression. Many different erosion processes act on this zone: gullying, piping, mudslides and armoured mud balls among others that contribute to export great quantity of material outside the basin. Depending on lithology and physico-chemical properties erosion acting processes differ. The knowledge of that processes help us to understand the great amount of soil loss that take place on the studied zone, bigger than those recommended