Aménagements littoraux et évolution d'un système lagunaire : étude de cas au Bénin

Coastal Development and Evolution of a Lagoon System ; A Case Study in Benin In 1885, when opening an artificial channel between lake Nokoue and the Atlantic Coast through the sandy coastal bar, man introduced a new element into the natural balance of the coastal system in South Benin. The disequilibrium that resulted gave immediate rise to significant repercussions on the environment and on its exploitation by the indigenous fishermen. Nevertheless, a new balance gradually emerged. It was soon disrupted, however, by the construction in the late 1950's of a deep water harbour in Cotonou, the existence of which completely changed the characteristics of the coastal current. Direct and indirect effects were so serious that in 1978 the authorities ordered the construction, near the channel mouth, of a regulating dam, the purpose of which was to check the penetration of salt water into lake Nokoue ; but this dam immediately led to unexpected disruptions, and its completion was rendered useless. The still unstable present situation is satisfactory as far as the fishermen of lake Nokoue are concerned. However, it entails very negative aspects for the development of Cotonou, a town where now thousands of urban dwellers are subject every years to floods, at times of disastrous proportions because of their extent and duration, and which, moreover, threaten their health as well as their homes.