Flexibility as a strategy to cope with uncertain water supply in spate irrigation*

Unpredictable flash floods in ephemeral rivers are the water source for spate irrigation systems. An important element in the success and sustainability of spate irrigation systems is their ability to cope with highly uncertain water supply and high sediment load. Flexibility is considered one of the key ingredients of coping strategies. However, the concept of flexibility in the context of spate irrigation systems is poorly defined. A framework to assess and operationalize flexibility in spate irrigation is lacking. In this paper we develop a conceptual framework by answering four principal questions and exploring eight flexibility characteristic features and five subfeatures. We explore the flexibility of traditional, improved and modernized spate irrigation systems to cope with high, low and untimely flood events. Flexible spate irrigation systems are highly dependent on system capabilities to deal with uncertainty and enable adjustments to change. The framework can be used as a guideline for water managers, farmers and decision makers for assessing and providing flexibility in spate irrigation systems.