Going down the drain, the proverbial preventable losses, is a common tragedy on Malawi’s roads. You certainly have seen roads without drainage and the pits sanitised as potholes where billions go down the drain due to endless patchwork. Near Kawale Bridge on the Area 23 Road in Lilongwe, someone blocked a drain to create a crossover to his or her roadside shop.
The blocked runoff cuts the recently repaired road, opening potholes only smaller than the ponds deepening near a second-hand vehicles’ market in Biwi Triangle nearby. Choked waterways continue to ruin the country’s road network, as rainwater strays into highways. Debris has clogged an entire lane on the Diamphwi section in Dedza along M1 and near Banana in Bangwe in Blantyre on the Robert Mugabe Highway between Limbe and Mulanje.
Motorists have no time to blink as they scramble for a constricted lane on the collision course. Associate professor Ignatius Ngoma, from the Malawi University of Business and Applied Sciences, says runoffs weaken a critical layer beneath tarmacs, causing potholes. “The best practice in pavement engineering is to keep moisture or water away from the road structure,” says the civil engineer.
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He splits bitumen roads into four layers that carry the load from vehicles and keep moisture away. “The other critical feature is the side drain, which takes the water from the road surface and surroundings to the nearest natural waterway to ensure the road structure remains dry,” he explains. The side drain, which measures at least 0.75 metres deep 0.75 metres, keeps roads stable.
When a pavement falls short of these specifications, water enters causes the road structure to disintegrate, crack and develop potholes, Ng’oma warns. The effects of neglected drainage haunt travellers nationwide.
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