Recent research on climate change, within the context of Sub-Saharan Africa, has shown
the vulnerability of groundwater resources to climate change and variability. In Senegal,
agriculture is among the most important users of groundwater resources, especially in the
northern coastal area called ‘Niayes’ where farmers practice irrigated agriculture and use almost
exclusively the quarternary sand aquifer for their irrigation needs during the dry season – which
is the main growing period. However, in Senegal, irrigated agriculture, particularly that of
horticultural crops, mostly grown in the Niayes, has attracted less research attention in terms of
studies focused on climate change or variability, compared to staple-growing rainfed regions.
In the Niayes region, farmers grow most of Senegal’s horticultural production. Combined with
human use of water resources, climate variability may threaten future irrigation water
availability in the area.
This paper uses an integrated hydroeconomic model and a rainfall generator to evaluate the
impact of rainfall variability on irrigation water availability and simulate its implications on
producers’ responses and groundwater management policy measures.
Results show that groundwater availability is diminishing over time, resulting in higher
water table depth and smaller water withdrawals by farmers who will tend to decrease the area
allocated to crops and favor the higher-valued crops. These trends are accelerated under a drier
climate regime. A taxation policy to stabilize the aquifer would induce a reduction of the area
under cultivation and have negative implications on revenues. Supply-side measures to enhance
recharge may not be technically or financially feasible. This suggests that Senegal needs to
develop groundwater management options that favor sustainable use of agricultural water
resources without hindering national horticultural production