In Part 1, we said Accra did not flood by accident.
That was not a slogan. It was a map.
To understand why the city keeps flooding, we must stop looking at water only when it enters our rooms. We must follow it from where it falls, through where it gathers, into where it should pass, and finally to where it should leave.
Accra was never supposed to drain through a random patchwork of roadside gutters. The city has an older and deeper water logic. Accra’s drainage system is based on natural watercourses, tributaries, lagoons, wetlands, floodplains, buffers, engineered drains and outfalls. Accra’s trouble began when the city started behaving as if that logic did not matter.
The main drainage spine for central Accra is the Odaw–Korle system. The system works through a basin chain. Runoff from urban areas enters tributaries such as Nima, Onyasia, Dakobi and Ado. These tributaries feed the Odaw River. The Odaw flows toward the Korle Lagoon. The Korle Lagoon functions as the downstream receiving body before water discharges toward the Atlantic Ocean.
The Odaw Basin covers a large urban catchment. It receives runoff from residential areas, markets, roads, commercial zones, informal settlements and paved urban surfaces. Because of this, any obstruction or capacity problem in the Odaw–Korle system affects more than one community.
The tributaries matter because they collect runoff before it reaches the Odaw. If tributaries are blocked, narrowed, filled, encroached upon or used as waste channels, flood risk rises in the communities around them and downstream.
The Odaw River matters because it is the main channel carrying runoff through the central urban basin. If it is silted, choked with waste, narrowed by settlement or unable to carry peak flows, water backs up into surrounding areas.
The Korle Lagoon matters because it is the receiving body at the lower end of the system. If the lagoon is silted, polluted, encroached upon or hydraulically constrained, the Odaw’s ability to discharge water is reduced.
The outfall to the sea also matters. Stormwater must not only enter drains and lagoons. It must also leave the city. If the downstream connection to the sea is weak or obstructed, the system backs up during heavy rainfall.
Accra’s drainage system is not limited to Odaw and Korle. The wider coastal system includes wetlands and lagoons such as the Densu Delta, Kpeshie Lagoon and Sakumo Ramsar Site / Sakumono Lagoon.
These wetlands and lagoons provide storage, overflow and drainage-support functions. They hold excess water, slow runoff and reduce pressure on engineered drains. They also provide ecological functions, but their flood-control role is central to urban planning.
A wetland is therefore not vacant land. A floodplain is not unused land. A buffer is not wasted space. These areas reduce flood risk by giving water room.
Historical planning records show that Accra’s drainage structure was recognised long ago. Recorded drainage-planning exercises include an overall drainage master plan for Accra Central in 1963, an addendum in 1967, a feasibility study in 1991, and a review and update in 1995 focused on the Odaw stream and tributaries.
The planning approach recognised that Accra needed basin-level drainage, not scattered gutter works alone. The city required protected waterways, maintained channels, preserved wetlands, functioning lagoon systems, clear outfalls and engineered flood-control infrastructure.
The current problem is that the drainage logic has been weakened.
Urbanisation has increased runoff. Settlement in the Odaw River Basin expanded by about 238.2% between 1991 and 2016. More buildings, roofs, roads, paved compounds and compacted surfaces mean less infiltration and more surface runoff.
This changes the behaviour of rainwater. Water reaches channels faster and in larger volumes. If drainage infrastructure has not expanded at the same pace, flood risk increases.
Wetland conversion has reduced natural storage. Research on the Densu Delta shows built-up expansion and wetland decline. Research on Sakumo/Sakumono shows major built-up expansion, floodplain loss, buffer encroachment and wetland degradation.
Buffer loss also reduces flood protection. Buffers keep buildings away from waterways, wetlands, lagoons and drains. They provide space for water to rise, spread or pass without immediately damaging property. When buffers are occupied, maintenance becomes harder and flood exposure increases.
Waste accumulation further reduces drainage capacity. Drains and watercourses affected by plastic waste, silt, household refuse and debris cannot carry water efficiently.
The downstream condition of the Odaw–Korle system remains important. Dredging, lagoon restoration, channel maintenance, solid-waste control, resettlement around flood corridors and improved outfall performance are all linked. Solving one part without the others will not fully restore the system.
Accra was therefore supposed to drain through a combined system:
Nima / Onyasia / Dakobi / Ado → Odaw River → Korle Lagoon → Atlantic Ocean
and through wider coastal wetland support systems including:
Densu Delta, Kpeshie Lagoon and Sakumo/Sakumono wetland areas
Part 1 ended with the truth that Accra’s flood problem is not only in the drains. It is in the planning.
The Part 2 finding is that Accra was supposed to drain through waterways, lagoons, wetlands, buffers and outfalls that worked together. Flood risk increased because many of those spaces have been narrowed, occupied, degraded or poorly maintained.
The planning must begin by following the water because water is the one witness Accra cannot intimidate.
It will always testify to the truth and every rainy season, it returns to the stand.
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#AccraFloods
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