With a rainfall of 1 mm, every square metre receives approximately 1 litre of rain water.
A rainfall of 1 mm supplies 0.001 m3, or 1 litre of water to each square metre of space.
So if your property is 70×100, and after building you cover the rest of the land with hard impermeable material, you are creating an area of 7,000 square foot or approximately 650 square meter for run-off water.
On the 28th of October 2019, nearly 115 mm of rain fell in East Legon. I think this weekend’s would measure same.
That means, your property contributed to approximately 74,750 litres of run-off water.
That’s approximately 15 ‘5000 litre’ polytanks of water poured into the system.
Do same maths for just the American house to AnC enclave and you’d realize that we contribute immensely to the flooding by how we build and treat the land.
We can reduce this by having more soft and greener compounds.
Tiles no, concrete no, hard pavements no adɔɔso, ɛyɛ tan, ɛma wiem yɛ hye and it contributes to flooding.
Always cover exposed land with grass, vegetables or some form of green, that helps with erosion and the build up of silt in the few drains we have.
Consider rainwater harvesting too. An underground tank here and there can store about 2 to 5 tanks of water.
Drains o drains. Factor that into your building…if you leave it to yaanom, nsuo de wo bɛkɔ.
-Kojo Boateng(Citi Fm)