Résumé
Land-use-change-induced increases in shallow groundwater levels across parts of the Sahel in recent years have coincided with expanded use of groundwater for irrigation. This study was conducted to assess the potential linkages and livelihood implications based on a field survey of nine villages building on previous hydrological studies. The results show that irrigators lack effective means of production and mostly rely on manual methods. Borehole usage is more profitable and reliable than shallower wells. Overall incomes from irrigation are relatively small and severely constrained by the limited field scale due to high establishment and operating costs.
Groundwater irrigation (GWI) is booming worldwide. In India much of the recent gain of the green revolution was fueled by GWI. GWI is often seen as an obvious solution for Sahelian farmers in areas remote from major rivers and dams, especially as an adaptation strategy to address climate variability and/or soil fertility reduction. In the Iullemmeden basin in south-western Niger, it has risen by about 4 metres over the past 50 years while rainfall patterns were approximately at average levels or even lower. While groundwater levels were rising, small-scale irrigated agriculture also expanded in this region, raising a number of issues regarding the opportunities and impacts of the enhanced water availability on irrigation development. This chapter seeks to answer specific questions concerning the sources of water used for irrigation, the socio-economic costs and benefits of GWI, and the major constraints faced by smallholder farmers who practice GWI in the Sahel region.