Coastal geomorphological change monitoring by remote sensing techniques in Nouakchott, Mauritania

Résumé En

Since the construction of a harbour, Port de l'Amitié, an important importation gate for Nouakchott in 1987, the previous coast dynamic equilibrium had been destroyed and thus a significant littoral geomorphological change has occurred, which has produced a severe degradation of the littoral and urban environment. Our research is focused on this coastal environmental change monitoring and its potential evolution estimation by remote sensing techniques using multi-temporal SPOT images and Markov chain analysis. The objectives of this paper are to understand the littoral change particularities, measure its development rates, evaluate the life-span of the harbour and future situation of the coastline and provide useful references for the similar management engineering. According to our research, the upper beach in the north of the harbour has extended by 0.916km2 (91.6ha) from 1989 to 2001 and the accretion will probably reach its maximum limit in about 11 years (in 2012), leading to an end of service of the harbour. The lower sandbar in the south has been eroded by 1.338km2 (133.8ha) and the coastline has landward retreated by 362m. This erosion has caused several times seawater inundation into the suburb and urban areas, provoking a deterioration of the urban environment.