Conjunctive use of surface and ground water resources in a community-managed irrigation system — The case of the Sidi Okba palm grove in the Algerian Sahara

Surface water and groundwater for irrigation are frequently used conjunctively, especially in semiarid and arid regions. Planning conjunctive management involves several difficulties, one of which is adapting irrigation institutions and infrastructure to coordinate the management of multiple water resources. This article focuses on the social and material dimensions of the conjunctive use of multiple water resources in a community-managed irrigation system when integrating new water resources. It explores the way the physical characteristics of these new water resources shape and are shaped by human-made arrangements, in particular irrigation institutions and infrastructure. The study was conducted in the ancient palm grove of Sidi Okba, located close to the city of Biskra in the Algerian Sahara. This palm grove has a long irrigation history based on the exploitation of several water resources: floodwater, intentional dam releases, uncontrolled dam leakages, and groundwater. Despite state interventions based on a mono-resource view of the irrigation system, the irrigation community developed the conjunctive use of multiple resources. Throughout its eventful history, the community adapted the irrigation institutions and infrastructure inherited from the spate irrigation period to incorporate new water resources. It also acquired the ability to negotiate with the state to manage its own system of water allocation and distribution. The social practices inherited from surface water irrigation played a crucial role in the integration of groundwater in the irrigation network. This study concludes that the ability of long-standing irrigation communities to renew their irrigation systems and to adapt to different global changes is decisive in explaining the sustainability of these systems. However, the boundaries of these irrigation systems changed with the incorporation of groundwater pumped from the confined aquifers, which means that the water resources cannot only be managed at the local level, putting at risk the sustainability of such irrigation systems. (Résumé d'auteur