This article examines the common-pool regime of Engaruka, a smallholder irrigation farming community in northern Tanzania. Irrigation is a complex issue due to water asymmetry. Water use is regulated in Engaruka through boundary, allocation, input and penalty rules by a users´ association that controls and negotiates water allocation to avoid conflicts among headenders and tailenders. As different crops -maize and beans, bananas and vegetables-are cultivated, different watering schemes are applied depending on the water requirements of every single crop. Farmers benefit from different irrigation schedules and from different soil characteristics through having their plots both downstream and upstream. In fact, depending on water supply, cultivation is resourcefully extended and retracted.Engaruka is an ethnically homogeneous and interdependent community where headenders and 2 tailenders are often the same people and are hence inhibited to carry out unilateral action. Drawing on common-pool resource literature, this study argues that in a context of population pressure alongside limited and fluctuating water availability, non-equilibrium behavior, consisting in negotiating water rights and modifying irrigation area continuously through demand management, is crucial for the satisfaction of basic and productive needs and for the avoidance of water conflicts.
Highlights: Water management in Engaruka is a common-pool regime The mgawa maji controls water distribution and avoids conflict Population pressure and fluctuating water supply lead to non-equilibrium behavior Non-equilibrium behavior requires water demand management Rights to agricultural expansion are constantly negotiated Keywords: smallholder farming, canal irrigation, common-pool regimes, non-equilibrium behavior, Tanzania
IntroductionGovernance and management of limited and fluctuating water supply is a fundamental challenge facing many irrigation systems. Water allocation in such a context can generate conflict, especially when the irrigation system is the most important source of livelihood for the local community (Tang, 1992). These circumstances are further strained when population pressure increases demand for an already limited resource. In studies of common-pool resources there is consensus that small homogenous local groups can bring about successful institutional arrangements that can ensure the sustainable use of resources. However, dealing with a resource such as irrigation water, is a challenge even for the most resilient local institutions as it is mobile, variable, inherently asymmetric and tends to be in control of headenders. (Komakech et al., 2012;Lein and Tagseth, 2009; Agrawal, 2001).
3Often the degree of water scarcity affects the rules, and their stringency, around water use (Tang, 1992). Free-riding becomes more common when pressure on the resource augments. In common property regimes there is no individual ownership over the resource at stake, but membership and benefits are harnessed through the fulfillment of certa...