Heavy rain does not have to become a disaster. The difference is usually drainage, and much of it is in our hands.
Rain is not the problem. Where it goes is.
When it rains on open ground, much of the water soaks into the soil. When it rains on a city, roofs, roads and compounds shed the water in minutes, and it all rushes to the same low points. If drains are too small, blocked or missing, the water has nowhere to go, and streets and homes flood.
As rainfall becomes less predictable and heavy downpours become more common in many parts of West Africa, a city’s drainage is the difference between an inconvenient afternoon and a lost year of savings.
Three reasons cities flood
1. Too much hard surface. Concrete and paving stop water from soaking in, so more runoff reaches the drains at once.
2. Blocked or undersized drains. Waste dumped in channels, silt, and construction over drainage paths reduce how much water can flow through.
3. Building in the wrong places. Floodplains, wetlands and natural waterways are the land’s own drainage system. Building on them moves the flooding onto people.
What good drainage looks like
- A clear path from every plot to a main drain, with no building across it
- Drains that are sized for heavy rain, and cleaned before the rainy season
- Soakaways, permeable paving and planted areas that let water sink in
- Rainwater collected from roofs in tanks, which also saves water
- Floor levels and plinths raised above the likely flood line
What you can do as a property owner
- Before you buy land, ask neighbours and local officials about its flood history. Visit during heavy rain if you can.
- Before you build, ask for a drainage plan, not only a building plan, and keep the water’s path clear.
- At home, keep gutters and drains clear, and do not dump refuse in drainage channels.
- Reduce hard surfaces. Use grass, gravel or permeable paving for part of your compound.
- Harvest rain. A simple tank slows runoff and gives you water for cleaning and gardens.
The cost question
Drainage is easy to cut from a budget because it is hidden once the work is done. But the cost of one flooded ground floor, with damaged walls, furniture, wiring and stock, is often higher than the cost of doing the drainage properly in the first place. This is one place where saving money at the start usually costs more later.
Planning a development, estate or school and want to be sure the drainage is right? Write to us at contact@autobillconst.com. We will gladly talk it through.