Plot‐scale effects on runoff and erosion along a slope degradation gradient

Abstract

Citation for published item:worenoEde ls rersD wF nd xioluD tFwF nd werinoEwrt¡ %nD vF nd iloxD fFF @PHIHA 9lotEsle e'ets on runo' nd erosion long slope degrdtion grdientF9D ter resoures reserhFD RT @RAF HRSHQF Further information on publisher's website: httpsXGGdoiForgGIHFIHPWGPHHWHHUVUS Publisher's copyright statement:worenoEde ls rersD wFD xioluD tFwFD werinoEwrt¡ %nD vF iloxD fFF @PHIHAF lotEsle e'ets on runo' nd erosion long slope degrdtion grdientF ter esoures eserh RT@RAX HRSHQD IHFIHPWGPHHWHHUVUS @hysAF o view the pulished open strtD go to httpsXGGdoiForgG nd enter the hysF Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. [1] In Earth and ecological sciences, an important, crosscutting issue is the relationship between scale and the processes of runoff and erosion. In drylands, understanding this relationship is critical for understanding ecosystem functionality and degradation processes. Recent work has suggested that the effects of scale may differ depending on the extent of degradation. To test this hypothesis, runoff and sediment yield were monitored during a hydrological year on 20 plots of various lengths (1-15 m). These plots were located on a series of five reclaimed mining slopes in a Mediterranean-dry environment. The five slopes exhibited various degrees of vegetative cover and surface erosion. A general decrease of unit area runoff was observed with increasing plot scale for all slopes. Nevertheless, the amount of reinfiltrated runoff along each slope varied with the extent of degradation, being highest at the least degraded slope and vice versa. In other words, unit area runoff decreased the least on the most disturbed site as plot length increased. Unit area sediment yield declined with increasing plot length for the undisturbed and moderately disturbed sites, but it actually increased for the highly disturbed sites. The different scaling behavior of the most degraded slopes was especially clear under high-intensity rainfall conditions, when flow concentration favored rill erosion. Our results confirm that in drylands, the effects of scale on runoff and erosion change with the extent of degradation, resulting in a substantial loss of soil and water from disturbed systems, which could reinforce the degradation process through feedback mechanisms with vegetation.Citation: Moreno-de las Heras, M., J. M. Nicolau, L. Merino-Martín, and B. P. Wilcox (2010), Plot-scale effects on runoff and erosion along a slope degradation gradient, Water Resour. Res., 46, W04503,

Slope shape effect on runoff and soil erosion under natural rainfall conditions

“…Early studies showed that general slope parameters influencing runoff generation and soil erosion are slope gradient, length, and shape (Wischmeier & Smith 1978). The effects of length (Kinnell 2000, 2007, Rejman & Brodowski 2005, Bagarello & Ferro 2010 and slope gradient (Bracken & Kirkby 2005, Assouline & Ben-Hur 2006, Moreno de las Heras et al 2010) on soil loss and runoff were studied extensively, with the general conclusions that eroded materials and runoff increase with higher slope steepness (Young & Mutchler 1969a, Wischmeier & Smith 1978, Liu et al 1994, Gabriels 1999, Chaplot & Le Bissonnais 2003. Moreover, a clear reduction in runoff for each unit of slope length was observed as slope length increased (Gascuel Odoux et al 1996, Aryal et al 2003, Parsons et al 2006.…”

Impact of soil erosion and runoff on mountain slopes of Mediterranean agroecosystems

“…De cualquier modo, la variación de la escorrentía con respecto al tamaño de parcela se hace prácticamente nula a partir de los 12 m de longitud de parcela. En consecuencia, de acuerdo con Moreno de las Heras et al (2010), podríamos tener en este estudio dos grupos de uso de suelo según su cobertura: los más protegidos serian Pinus, pastizal y matorral y los de menor cobertura almendro, olivar y suelo abandonado. Las tasas de tolerancia a la pérdida de suelo pueden diferir según la cubierta vegetal, clima, topografía, y diversas características del suelo.…”

Coupling the modified SCS-CN and RUSLE models to simulate hydrological effects of restoring vegetation in the Loess Plateau of China

“…For example, field observations in the Negev Highlands showed that frequency and magnitude of the specific runoff yield decreased with increasing area as a result of flow discontinuity and deposition processes along the hillslope (Yair and Raz-Yassif, 2004). Moreno-de las Heras et al (2010) observed that unit area sediment yield declined with increasing plot length for the undisturbed and moderately disturbed sites, but it actually increased for the highly disturbed sites, which was especially clear under highintensity rainfall conditions in a Mediterranean dry environment. Therefore, the plot-scale effects of runoff and erosion were dependent on the extent of degradation.…”

“…Liu et al (2012) found that soil loss rates decreased with the plot area in Group 2 and Group 3 plots with longer restoration time, but they increased over an area threshold in Group 1 plot located at the early stage of revegetation, which was not totally consistent with the USLE/RUSLE model. One of the main reasons for the complex plot-scale effects of soil loss is the connectivity and distribution of runoff and sediment source and sink areas on hillslope (Yair and Raz-Yassif, 2004;Parsons et al, 2006;Moreno-de las Heras et al, 2010). Therefore, not only plot length, but the other factors such as rainfall regime, soil property, and vegetation cover contribute to scale variations of runoff and soil loss.…”