Effectiveness of Vegetation Barriers for Marly Sediment Trapping. Rey, F. 29(9):1161–1169.
Effectiveness of Vegetation Barriers for Marly Sediment Trapping [link]Paper  doi  abstract   bibtex   
Vegetation barriers can be effective in trapping eroded sediment, but little knowledge exists on the characteristics of vegetation barriers efficient in trapping all sediments from an eroded zone upslope. The objective of this study is to quantify the effectiveness of vegetation barriers for marly sediment trapping. Relationships between eroded zones and vegetation barriers - composed of low vegetation, that is to say herbaceous and under-shrub layers - located downslope and sufficient to stop all the sediments eroded above, have been studied in the Brusquet experimental marly catchment in the French southern Alps. Forty plots with surface areas less than 500 m2 were studied. The eroded zones and the vegetation barriers were characterized by their surface areas, between which an average linear relationship exists. Results also showed that, for a marly plot with a given surface area, a downslope vegetation barrier covering only 20 per cent of this plot can be sufficient to trap all the sediments eroded above it. [Excerpt: Study site] Observations were carried out in the Brusquet experimental catchment (Alpes-de-Haute-Provence) in the French Southern Alps (Figures 1 and 2). This marly catchment has a surface area of 108 ha. The altitude ranges from 802 to 1263 m, with northerly exposure. Average annual precipitation is about 900 mm. The heaviest rainfall events recorded over 24 hours was about 100 mm and the average annual temperature is 10 °C. This catchment was restored more than one century ago. Bioengineering work in gullies has permitted vegetation establishment on gully slopes and floors and this catchment now has a vegetation cover of 87 per cent. Vegetation is primarily made up of Austrian black pine ( Pinus nigra Arn. subsp. Nigra ) for the trees, whitebeam ( Sorbus aria ) and opalus maple ( Acer opalus ) for the shrub layer, restharrow ( Ononis fruticosa ) for the under- shrub layer and, finally, calamagrostide ( Calamagrostis argentea ) for the herbaceous layer [Conclusion] The results taken as a whole show that a linear relationship exists between the surface area of an eroded zone and the surface area of an efficient vegetation barrier downslope. This relationship does not depend on slope variation, especially for slopes steeper than 73 per cent. We also showed that, to trap the sediments originating from an eroded zone, an optimal surface area of vegetation barrier can be sufficient downslope. This field study, however, is limited due to the uncertainty concerning the significance of the heavy rainfalls that had occurred during recent years before the study period. Improved knowledge on the effectiveness of vegetation barriers for sediment trapping could have applications by taking better account of this influence of vegetation in erosion models (Sanchez and Puigdefabregas, 1994; Takken et al ., 1999). Indeed, these models often overestimate sediment losses, at the inter-annual or event scales, because they do not take into account vegetation distribution (Mathys et al ., 2000). It could also help land managers to determine the optimal size of the bioengineering works needed to trap eroded sediments during rehabilitation operations on degraded gullies (Sharma et al ., 1999).
@article{reyEffectivenessVegetationBarriers2004,
  title = {Effectiveness of Vegetation Barriers for Marly Sediment Trapping},
  author = {Rey, F.},
  date = {2004-08},
  journaltitle = {Earth Surface Processes and Landforms},
  volume = {29},
  pages = {1161--1169},
  issn = {0197-9337},
  doi = {10.1002/esp.1108},
  url = {https://doi.org/10.1002/esp.1108},
  abstract = {Vegetation barriers can be effective in trapping eroded sediment, but little knowledge exists on the characteristics of vegetation barriers efficient in trapping all sediments from an eroded zone upslope. The objective of this study is to quantify the effectiveness of vegetation barriers for marly sediment trapping. Relationships between eroded zones and vegetation barriers - composed of low vegetation, that is to say herbaceous and under-shrub layers - located downslope and sufficient to stop all the sediments eroded above, have been studied in the Brusquet experimental marly catchment in the French southern Alps. Forty plots with surface areas less than 500 m2 were studied. The eroded zones and the vegetation barriers were characterized by their surface areas, between which an average linear relationship exists. Results also showed that, for a marly plot with a given surface area, a downslope vegetation barrier covering only 20 per cent of this plot can be sufficient to trap all the sediments eroded above it.

[Excerpt: Study site] Observations were carried out in the Brusquet experimental catchment (Alpes-de-Haute-Provence) in the French Southern Alps (Figures 1 and 2). This marly catchment has a surface area of 108 ha. The altitude ranges from 802 to 1263 m, with northerly exposure. Average annual precipitation is about 900 mm. The heaviest rainfall events recorded over 24 hours was about 100 mm and the average annual temperature is 10 °C. This catchment was restored more than one century ago. Bioengineering work in gullies has permitted vegetation establishment on gully slopes and floors and this catchment now has a vegetation cover of 87 per cent. Vegetation is primarily made up of Austrian black pine ( Pinus nigra Arn. subsp. Nigra ) for the trees, whitebeam ( Sorbus aria ) and opalus maple ( Acer opalus ) for the shrub layer, restharrow ( Ononis fruticosa ) for the under- shrub layer and, finally, calamagrostide ( Calamagrostis argentea ) for the herbaceous layer

[Conclusion] The results taken as a whole show that a linear relationship exists between the surface area of an eroded zone and the surface area of an efficient vegetation barrier downslope. This relationship does not depend on slope variation, especially for slopes steeper than 73 per cent. We also showed that, to trap the sediments originating from an eroded zone, an optimal surface area of vegetation barrier can be sufficient downslope. This field study, however, is limited due to the uncertainty concerning the significance of the heavy rainfalls that had occurred during recent years before the study period. Improved knowledge on the effectiveness of vegetation barriers for sediment trapping could have applications by taking better account of this influence of vegetation in erosion models (Sanchez and Puigdefabregas, 1994; Takken et al ., 1999). Indeed, these models often overestimate sediment losses, at the inter-annual or event scales, because they do not take into account vegetation distribution (Mathys et al ., 2000). It could also help land managers to determine the optimal size of the bioengineering works needed to trap eroded sediments during rehabilitation operations on degraded gullies (Sharma et al ., 1999).},
  keywords = {*imported-from-citeulike-INRMM,~INRMM-MiD:c-13830249,acer-opalus,alpine-region,calamagrostis-argentea,forest-resources,france,ononis-fruticosa,pinus-sylvestris,sediment-yield,soil-erosion,soil-resources,sorbus-aria},
  number = {9}
}
Downloads: 0