THE VALUE OF WATER - FLOODPLAIN VERSUS LARGE-SCALE IRRIGATION BENEFITS IN NORTHERN NIGERIA

Many African river floodplains are disappearing or being modified as t he result of water management activities, in particular large-scale ir rigation schemes. Often any resulting impact on downstream wetland ben efits is ignored. By combining hydrological and economic analyses we s imulate different scenarios for large-scale irrigation schemes in the Hadejia-Jama'are River Basin in northern Nigeria. We compare the agric ultural, fishing and fuelwood benefits lost through reduced flooding d ownstream against the gains from increased irrigation production upstr eam. Our analysis suggests that the irrigation benefits can only parti ally replace the lost benefits from reduced floodplain inundation. Giv en that several upstream irrigation schemes are completed or currently under construction, our simulations show that the introduction of reg ulated flood releases is the best hope of minimizing further losses of floodplain benefits. Further expansion of large-scale irrigation with in the river basin should also be avoided.