The Inner Niger Delta in the Western Sahel zone in Africa supports more than a million people. They make their living as fishermen, cattle breeders or farmers, using the annual rising and receding of waters in the river and floodplains. Such wetlands are of course of vital importance, especially in a semi-arid region like the Sahel where annual rainfall fluctuates considerably. And this importance is not just for people: nearly 4 million waterbirds call the Niger Delta their home.

Two dams have been constructed upstream in the Niger river, Selingué dam for mainly hydropower, and the Markala dam for irrigation of the Office du Niger area. Although these dams have improved irrigated agriculture, the benefits vary by season: in dry periods the dams can decrease the water flow up to 30%, with strong negative effects on downstream water use like in the Inner Niger Delta.

Now a third dam has been proposed - the Fomi dam - and a comprehensive cost-benefit discussion is now taking place: are the economic benefits bigger than the investment costs and the expected losses in productivity downstream? Wetlands International and RIZA have developed a decision-support system for river-management that helps local communities answer these complicated questions. First project analyses show that the costs of building a new dam would be substantial and that development efforts should focus instead on improving the efficiency of the existing infrastructure and on supporting the economic activities in the delta, rather than investing in new infrastructure.