In Northern Mali, natural depressions are filled when the Niger River overflows. They are therefore of high value for agriculture. The government chose to construct heavy irrigation infra-structures as a priority for the development of the region. As social peace in Northern Mali is an important issue, this priority has economic, social, and political consequences. Nevertheless, the analysis of the story of Lake Horo development (the only lake that has been developed for irrigation in Mali) and its consequences leads to questions about developmental strategies based solely on irrigation, when the traditional flood recession agriculture advantages are still valuable in this kind of natural and social context.