Financed by the World Bank, the WACA (West African Coastal Management) programme was initiated in response to the fact that coastal areas, which are among the most densely populated and dynamic regions on the African continent, are being seriously affected by the over-exploitation of resources, pollution and climate change. The World Bank estimates that around a third of the inhabitants of West Africa live in these coastal areas, which are responsible for 56% of the GDP of the countries concerned (fishing, agro-industry, port activities, oil industry, etc.). However, under the impact of climate change, these areas are undergoing worrying transformations (warming and rising sea levels, landslides, storm surges and flooding, coastal erosion of up to 10m/year, etc.). They are also subject to major urban and industrial pollution, overexploitation of resources and degradation of natural habitats.

In order to build a strategy for preserving the coastline and safeguarding the associated ecosystem services, WACA is involving a number of countries in these various challenges by financing studies and action plans. Artelia is involved in a number of projects under this programme, and in 2020 carried out a study on protecting 50 km of coastline between Togo (from Gbodjomé to Hillacondji) and Benin (from Hillacondji to Gbekon) against erosion. Experience has shown that upstream solutions can have negative repercussions downstream, so concerted management of the coastline between the two countries has become an essential approach.

Involving its experts and tools (modelling, drone monitoring), Artelia began by characterising this cross-border erosion, assessing sediment dynamics and modelling the evolution of almost 80 km of coastline from the border between Ghana and Togo to La Bouche du Roy (Benin). Our teams then advised the relevant parties on the various protection techniques available, proposing several combinations of soft and structural measures, in order to achieve a jointly developed and validated solution.