Stratégies de conservation, mise en œuvre et réactions du milieu et des paysans dans l'Ouest algérien (Strategies and implementing of conservation practices ; retroactions in the physical and rural environment in western Algeria)

Taabni, Mohamed; Kouti, A.

doi:10.3406/bagf.1993.1709

Cited by 2 publications

(1 citation statement)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In Oran, Taabni and Kouti [17] noted that benches that were not kept up became a factor for increased erosion, since the slightest break that was not repaired led to a chain-like reaction from bench to bench during prolonged torrential rainfall. Moreover, Roose et al [12,13] found that Algerian small farmers object to contour benches on their lands and refuse to see to their upkeep, believing that the benches hinder free movement and waste useable agricultural land, which is not compensated enough by the increase in crop output.…”

Section: Introductionmentioning

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

View full text Add to dashboard Cite

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.

show abstract

Section: Introductionmentioning

confidence: 99%