Coastal risk assessment - Cotonou East Site
Monitoring, analysis and prediction
Monitoring, analysis and prediction
The figure below represents the yearly changing rates of the coastlines between 2019 and 2025. The zones in orange represent an erosion trend and in green an accretion trend.
By comparing annual coastline positions, we observe a consistent retreat in some areas, signaling coastal erosion linked to both natural and anthropogenic pressures. Other regions show slight advances due to sediment deposits and natural barriers. This analysis is crucial for identifying vulnerable zones and designing adaptive strategies for coastal development and protection.
Predictive models suggest an retreat of the coastline of an additional 5 to 10 meters by 2030, and up to 20 meters by 2050. These data strongly guide the installation of infrastructure at a reasonable distance from the shore.
Based on regional sea level rise estimates and historical erosion rates, these forecasts integrate both climate change scenarios and local dynamics. The projections highlight the urgent need for forward-thinking land use planning, reinforcing setbacks, and sustainable coastal engineering interventions to safeguard infrastructure and ecosystems in the coming decades.
The NDVI indicates a slight degradation of vegetation cover in the area — a signal of progressive land use or stress.
The NDWI, on the other hand, reveals stable soil moisture, with distinct peaks during the rainy seasons.
Together, these indicators highlight a landscape that is partially anthropized yet still resilient to environmental changes. Monitoring these indexes over time provides insight into land health and guides decisions on conservation, reforestation, and site planning in dynamic environments like coastal zones.
Based on the previous analyses, the coastal development at the project site is qualified at high risk against erosion. In addition, given the sea-level rise projections and the coastline retreat, sea floods are likely to impact more significantly the nearshore site activities during storm events.
We anticipate that by 2030 nearly half of the fictive project site will be eroded, making any construction on the zone not viable in the current conditions.
To effectively address the erosion issue over the long-term, we recommend contacting the government coastal protection department to discuss the status of the integrated coastal zone management actions under investigation (nature-based, hybrid solutions) to allow future sustainable and resilient developments over the region.
In the meantime, we strongly advise a continuous monitoring programme over the coming months and years to track coastline changes. To facilitate it, Antea Group has developed a specialized tool to provide valuable data and visual insights to support adaptive management and decision-making.