Hydrologic Impacts of Contour Ridges in Tunisian Semi-arid Regions

Nasri Slah¹, Baccari Noamene², Jean Marie Lamachère³, Mohamed Rached Boussema²

¹ Institut National de Recherche en Génie Rural, Eaux et Forêts (INRGREF), Tunisia
e-mail: nasri.slah@iresa.agrinet.tn

Abstract

During the three last decades, about one million hectares of hill slopes field lands were arranged by earth contour ridges (or earth benches) in Tunisian semi-arid regions. These water harvesting techniques allow to reduce soil water runoff erosion and support the infiltration of surface waters on the space between two successive contour ridges. Authors of this work studied the hydrologic impact and the efficiency of these techniques on an elementary scale and on catchment scale, and also their impact on the reduction of water runoff and silting up towards a hill reservoir existing downstream these contour ridges.

Keywords: water runoff, contour ridges, effectiveness, hill reservoir, erosion, semi-arid, Tunisia