Spate Irrigation Systems and Watershed Development in Eritrea: the case of Sheeb watershed

Abstract

This paper describes the interactions of the Spate Irrigation System (SIS) in Eritrea with their upper watersheds, as a case study in Sheeb watershed. The spate irrigation practices, among others, include techniques to harvest runoff water, sediments, and nutrients. A strong relationship exists between the SIS in the lowlands of Eritrea and their upper watersheds. For example, the spate irrigation system in the lowlands of Sheeb area entirely depends for water, soils and nutrients on the resources of its upper watershed. Interventions of soil and water conservation practices in the upper watershed could reduce soil loss and sedimentation rates, in the long term. And, this in turn, lowers the quantity of sediments and nutrients harvested in spate irrigated fields of Sheeb. However, the runoff volumes may not be affected much (by such conservation measures) mainly because of the steep topography of the upper watershed with shallow soils, which induces more runoff than infiltration into the soils. It can be concluded that the lessons learned from the Sheeb watershed will be very useful for planning watershed development projects in other spate irrigated areas of Eritrea and possibly in other parts of the world where similar systems are practice