Importance du facteur lithologique sur le développement des ravins du bassin versant d'Oued Maiez en Tunisie Centrale

Felfoul, Mennoubi Sfar; Snane, Mohamed Habib; Mlaouhi, A.; Megdiche, Malik

doi:10.1007/s100640050047

Cited by 10 publications

(5 citation statements)

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“…The extreme intensity of erosion in Fidh Ali catchment can be explained by its soil composition that contains a very high percentage of marly gypsum showing intense swelling/shrinkage processes (clayey soils). They are known to increase soil sensitivity to erosion (Cantón et al ., ; Sfar Felfoul et al ., , ) as they facilitate both aggregate dispersion and gully initiation. In this catchment, this specific lithological feature directly appears as the first‐order factor driving the very high erosion rates.…”

Section: Discussionmentioning

confidence: 99%

Relative Contribution of Rill/Interrill and Gully/Channel Erosion to Small Reservoir Siltation in Mediterranean Environments

et al. 2015

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Reservoir siltation because of water erosion is an important environmental issue in Mediterranean countries where storage of clear surface water is crucial for their economic and agricultural development. The high density of gully systems observed in Mediterranean regions raises the question of their contribution to reservoir siltation. In this context, this study quantified the absolute and relative contributions of rill/interrill and gully/channel erosion in sediment accumulation at the outlet of small Tunisian catchments (0·1–10 km2) during the last 15 years (1995–2010). To this end, a fingerprinting method based on measurements of caesium‐137 and total organic carbon combined with long‐term field monitoring of catchment sediment yield was applied to five catchments in order to cover the diversity of environmental conditions found along the Tunisian Ridge and in the Cape Bon region. Results showed the very large variability of erosion processes among the selected catchments, with rill/interrill erosion contributions to sediment accumulated in outlet reservoirs ranging from 20 to 80%. Overall, rill/interrill erosion was the dominant process controlling reservoir siltation in three catchments whereas gully/channel erosion dominated in the other two catchments. We identified the presence of marly gypsum substrates and the proportion of catchment surface covered by soil management/conservation measures as the main drivers of erosion process variability at the catchment scale. These results provided a sound basis to propose guidelines for erosion mitigation in these Mediterranean environments and suggested to apply models simulating both rill/interrill and gully/channel erosion in catchments of the region. Copyright © 2015 John Wiley & Sons, Ltd.

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Section: Discussionmentioning

confidence: 99%

Relative Contribution of Rill/Interrill and Gully/Channel Erosion to Small Reservoir Siltation in Mediterranean Environments

et al. 2015

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“…Il s'appuie sur l'analyse de la densité de drainage, définie comme étant le rapport entre la longueur du réseau hydrographique et la superficie de la zone considérée (Tarboton et al 1992). Outre le fait que la densité de drainage est considérée comme un puissant paramètre de synthèse de la répartition et de l'organisation spatiale du réseau hydrographique (Rodriguez-Iturbe et al 1982, Humbert 1990), elle permet de comparer les longueurs et/ou les évolutions de longueurs des ravines sur des secteurs de superficie différente (Sfar Felfoul et al 1999, Bouchnak et al 2004.…”

Section: Méthodeunclassified

“…Certaines se sont orientées vers le rôle décisif des caractéristiques biophysiques (Brahamia 1993, Kouri et al 1997, Sfar Felfoul et al 1999, Kirkby et Bull, 2000, Moeyersons 2003, Poesen et al 2003, Valentin et al 2005, Vanwalleghem et al 2005) et d'autres vers des facteurs anthropiques propres à chaque région (Podwojewski et al 2002, Gomez et al 2003, Vanacker et al 2003, Nyssen et al 2004a, 2004b, Poesen et Vandekerckhove 2004.…”

Section: Introductionunclassified

Efficacité des aménagements de lutte contre le ravinement: cas du bassin versant d’El Hnach (Tunisie)

Rebai¹,

Raclot

Ouezdou³

2013

Hydrological Sciences Journal

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“…On gypsum clay, breakage is the consequence of a strong tendency in clay soil to runoff and to dissolving the gypsum contained in the soil used to construct the benches, which leads to the formation of tunnels called piping. Moreover, on this type of formation, bench breakage creates gullies [16]. In order to avoid the overdeepening of these gullies (Fig.…”

Section: Recommendationsmentioning

confidence: 99%

Efficiency of contour benches, filling-in and silting-up of a hillside reservoir in a semi-arid climate in Tunisia

Baccari

Boussema

Lamachère³

et al. 2007

Comptes Rendus. Géoscience

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The El Gouazine catchment area (18.1 km 2 ), located in semi-arid central Tunisia (average annual rainfall 350 mm), was equipped with total retention contour benches on 43% of its surface area between June 1996 and July 1997. In order to analyze the efficiency of these benches on the catchment area, different thematic maps (slope, lithology, land use, hydrographic network) were crossed using GIS with a map that located the benches and their breaks. Specific topographical surveys were also carried out on a series of 14 benches' in order to characterize the development of their holding capacities. To evaluate the impact of the contour bench installation on the catchment area, the change of liquid and solid inflow was measured at the catchment area outlet two years before and eight years after the bench installation. On-site surveys showed that contour bench dysfunction in the El Gouazine catchment area could not have been caused by man. However, three main physical causes could explain the dysfunction: placement of benches on gypsum clay soils, location of breaks on the hydrographic network, and slope greater than 25%. Topographic surveys showed that the benches initial holding capacity varied between 1 and 3 m 3 per linear metre for a construction standard fixed at 2.28 m 3 . These surveys also showed that, nine years after their construction, the benches had lost 10 to 50% of their initial holding capacity. After installing benches in the El Gouazine catchment area, solid inflow was only reduced by 30%, whereas liquid inflow was reduced seven to eight times during a fouryear period, which greatly limited the possibility of downstream irrigation. Annual runoff coefficients, at 4.5% before bench installation, were again at 5.1% in 2002-2003, and the silting-up rate was evaluated, in June 2005, as identical to its value before installation. Bench breakage and silting up of upstream canals explain these changes. The results of this study should serve to improve contour bench installation plans of catchment areas in semi-arid climates by both increasing bench efficiency and, at the same time, conserving sufficient water flow to hillside reservoirs. To cite this article: N.

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Importance du facteur lithologique sur le développement des ravins du bassin versant d'Oued Maiez en Tunisie Centrale

Cited by 10 publications

References 0 publications

Relative Contribution of Rill/Interrill and Gully/Channel Erosion to Small Reservoir Siltation in Mediterranean Environments

Relative Contribution of Rill/Interrill and Gully/Channel Erosion to Small Reservoir Siltation in Mediterranean Environments

Efficacité des aménagements de lutte contre le ravinement: cas du bassin versant d’El Hnach (Tunisie)

Efficiency of contour benches, filling-in and silting-up of a hillside reservoir in a semi-arid climate in Tunisia

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