By Environmental Engineer, Dr Juliet Ohemeng-Ntiamoah, has called for greater attention to silt accumulation in Ghana’s drainage systems, saying solid waste is not a major cause of flooding and that poor urban planning is contributing to clogged gutters.
Speaking on Joy FM’s Super Morning Show on Wednesday, July 8, Dr Ohemeng-Ntiamoah said public discussions following recent flooding have largely focused on choked gutters caused by waste, but stressed that this overlooks the more fundamental causes of flooding.
“I know this can be a little controversial, but I have an article out there that I have mentioned, that solid waste is not a major cause of flooding,” she said.
According to her, while solid waste contributes to drainage challenges, the dominant material blocking drains across the country is actually silt and sand.
“If we look at our gutters, you will see that the main choke is silt and sand, and that is because of the nature of our city,” she explained.
Dr Ohemeng-Ntiamoah attributed the problem to the large number of unpaved and unconstructed roads across Ghana’s cities, particularly feeder roads connecting major roads.
“We have a lot of unpaved roads or unconstructed roads, feeder roads joining main roads. Now all that silt, when it rains and the wind blows, carries all that silt and sand into our gutters.”
She noted that although authorities frequently undertake desilting exercises, little attention is paid to preventing the continuous accumulation of sediment in drainage systems.
“When we are desilting the Odaw and all those tunnels, it’s mainly sand that we are taking out of that. And how do we prevent or reduce or minimize the amount of silt and sand that choke our gutters?” she asked.
To address the problem, she called on government to prioritise the construction of unpaved roads, saying they are a major source of dust and sediment.
“The government needs to make sure that all those smaller unconstructed roads are constructed. Because when they are left unconstructed, they are dusty, and all that dust and all that silt get into the gutters.”
She also advocated for greater investment in green infrastructure to reduce stormwater runoff.
“It’s hard to find places in Accra that are well green… the lack of all that is increasing what we call runoff. So when it rains, it doesn’t have anywhere to seep into the soil. It runs off quickly… then flooding is occurring.”
Dr Ohemeng-Ntiamoah further recommended the use of permeable pavements instead of conventional tarred surfaces to improve groundwater infiltration and reduce surface runoff.
Summing up her argument, she stressed that addressing sediment buildup is indispensable to solving Ghana’s flooding challenges.
“Our gutters are choked due to silt or sand, and it’s as a result of how our cities are planned or unplanned. If we want our gutters or drainage systems to be clean to allow the free flow of rainwater, then we need to address silt. We cannot talk about waste management without addressing silt.”
