Accra: The Director of NADMO's Inspectorate Unit, Richard Amo Yartey, recently highlighted the core issues contributing to Accra's persistent flooding problem: silted drainage channels, increased mountain runoffs due to vegetation clearance, and the sale of wetlands that should absorb excess water.
According to Ghana Web, this diagnosis identifies the key failures that have led to the crisis-a clogged drainage network, insufficient natural buffers, and the loss of wetlands. The challenge now lies in implementing a comprehensive solution to revamp the entire drainage system of Accra to prevent future flooding.
Accra was historically equipped with a natural drainage system that included the Odaw River, the Densu, the Sakumo, and other lagoons that effectively carried rainwater from the Akuapem hills to the sea. However, over the past four decades, this natural system has been dismantled due to human activities such as silting, vegetation clearance, and wetland encroachment. Re-engineering the drainage system requires rebuilding this network and integrating modern infrastructure.
A holistic approach to the problem includes treating the catchment area comprehensively rather than focusing solely on gutters. The Ghana Institution of Engineers has advocated for a unified metropolitan management structure to oversee the entire basin, from the hills to the sea, ensuring coordinated action across jurisdictions.
Moreover, slowing down water flow at its origin is crucial. Nature-based stormwater management techniques such as permeable pavements and rain gardens can absorb water efficiently, preventing it from overwhelming drainage channels. Mandatory rainwater harvesting for larger buildings could also alleviate flooding and address water shortages.
Addressing mountain runoff is another critical aspect. Reforestation and sediment traps on the hills and upper tributaries can help manage rainwater before it reaches the city. Furthermore, restoring natural wetlands is essential, as they serve as effective flood-control infrastructure.
Regular maintenance of existing drainage channels is necessary to ensure they function efficiently. This includes permanent dredging and widening of channels in dense areas. Additionally, constructing flood retention basins, as planned under the Greater Accra Resilient and Integrated Development (GARID) programme, can help manage excess stormwater.
Finally, future developments should incorporate drainage systems designed to handle increased rainfall intensity due to climate change. This proactive approach requires governance and strict enforcement to maintain infrastructure integrity and prevent misuse.
The cost of re-engineering Accra's drainage system is significant but pales in comparison to the potential losses from continued flooding. With a World Bank-backed framework already in place, what remains is the political will to treat flooding as an engineering challenge to be solved. By building a resilient system, Accra can transform into a city capable of managing its floodwaters effectively.