In recent years more recognition is given to the benefits and risks of private smallholder irrigation development across sub-Saharan Africa. It is acknowledged for its capacity to adapt to local circumstances and challenges. This study assesses the heterogeneous character of private smallholder irrigation in the challenging environment of southern arid Zimbabwe, where family farms operate along sand river aquifers, forming a reliable natural storage of shallow groundwater. It investigates the drivers, characteristics, obstacles and adaptive capacity of this yet undocumented form of private irrigation in a historically marginalised area, and in particular also the discontinuation of these informal irrigation ventures. The research combines results from analysing satellite images, and quantitative and qualitative field work, whereby a social-ecological system perspective is applied. This form of private smallholder irrigation is distinct from most other documented cases in sub-Saharan Africa. First, because of the unique interrelation between the water source, technology need and fuel-dependency in an economically marginalised area. Second, because drivers for the emergence of private smallholder irrigation are not market-based but crisis-driven; recurrent droughts and frequent dry-spells, failure of collectively-managed irrigation schemes, and persistent economic instability. As a result, many families cease operations because they reach the limits of their adaptive capacity or they migrate. Those who succeed, manage to benefit from the abundance of water stored in sand rivers, the mobilisation of knowledge and cash through rural networks, and the existence of cross-border trade opportunities. However, they hardly ever pass the level of subsistence in an area where stable markets are absent. Organising potential support to private smallholder irrigation remains a challenging and disputable avenue as this might undermine its independent and adaptive nature.

Alluvial aquifers in seasonal rivers are a yet underutilised resource in many (semi-)arid regions of Africa. These so-called sand river aquifers provide nature-based water storage within easy reach because they are shallow. They form a significant potential renewable source of water for irrigation development. Innovative approaches and solutions are needed to sustainably increase productive use of this resource to enhance rural livelihoods. The A4Labs action research explores the potential and pitfalls of introducing solutions designed for individual smallholder farmers. This entails innovation in three domains: the technology used (manually-installed shallow well-points in or next to a sand river combined with solar-powered water pumps), the arrangement (individual smallholder farmers), and the purpose (market-oriented farming). Pilots were established in the Limpopo river basin in Zimbabwe and Mozambique. Monitoring and assessment are ongoing, but preliminary findings indicate that successful adoption of the approach was not constrained by water availability. Despite the fact that these pilots were established during two subsequent drought years, there was no difficulty in accessing freshwater in sufficient quantity. Instead, successful adoption depends on previous farming experience, market access, and the possibility to grow adaptively in terms of technology, scale and financial risks. In addition, establishing an individual farm to grow cash crops requires acceptance and new skills, as irrigation for smallholder farmers in Africa has traditionally been framed as a communal activity in “collective” irrigation schemes with strong support by outside agencies, and with the well-known collective action challenges. This action research has also estimated that the potential for upscaling this innovation in the Limpopo river basin is significant. Our innovative solution for accessing water stored in shallow alluvial aquifers can start small, is within reach of smallholder farmers (initial investment being less than US$1,000/0.2 ha), and is scalable as farmers can gradually improve their system and expand. Moreover, the solution allows for the application of “adaptive development pathways” at the river-stretch scale.