Dredging of Odaw River begins to mitigate Accra floods
Dredging of the Odaw River drainage system, which has become a receptacle for a chunk of Accra’s waste, has commenced in earnest as government moves to prevent the recurrent flooding in the capital as the rains set in this year.
Engineers and workers of Dredge Masters are expected to within the next 45 days, flush out a chunk of the waste material, mostly sand and garbage, which have built up in the drainage system for almost two years.
As of yesterday morning when a team of journalists visited the Kwame Nkrumah stretch of the over 1000 metre-long drainage system, huge volumes of silt had been taken out onto the bank of the drains and were being loaded out of the site to prevent it from being washed into the system.
The dredging exercise is being carried out day and night in a bid to restore the efficiency and holding capacity of the drainage to be able to contain the volume of water, especially when it rains. This will avoid flooding.
It followed a two-year contract signed between the government and Dredge Masters in February 2019 for the dredging and maintenance of the Odaw River drainage system and the Korle Lagoon to avert the perennial flooding in Accra during the rainy season.
Per the contract, Dredge Masters, which is a subsidiary of the Jospong Group of Companies, is required to redesign and construct the Korle Lagoon Ecological Restoration Project (KLERP) interceptor and breakwater at the outfall within the next two years.
In partnership with the Accra Metropolitan Assembly, Dredge Masters is also clearing out encroachers and squatters along the drainage system whose activities have been compounding silting of the drains.
Dredge Masters in June 2016 signed a similar two-year contract with the government which ensured chocked silt in the Odaw drainage system was flushed out to prevent flooding.
Over one million cubic metres of dredged materials were removed from the system and the Korle Lagoon, exceeding the contract volume, but upon the expiration of the contract, the system became chocked again within a short time.
Operations Manager at Dredge Masters, Sena Adiepena, said they kept monitoring the situation after the expiration of their initial contract and realised that the rate of siltation was quite rapid and required continuous de-silting and dredging.
He explained that the level of siltation causes the drain to lose its holding capacity thus causing the water to overflow its banks resulting in flooding.
Mr Adiepena underscored the need for the Odaw drains to be dredged, arguing that “if we lose its capacity it tends to easily overflow its banks and its very key and very important that we maintain its original design so that it doesn’t overflow with the slightest rainfall”.
In his view, dredging the Odaw drainage system quarterly will be the best way to ensure it is maintained to perform optimally.
The Operations Manager said despite dredging there will still be “minimal deposits settling” in the drainage system, but noted continuously dredging it will ensure that “we don’t have loss of capacity of this drain”.
“The main reason for the flooding is not the rubbish; it is the silt deposits that have resulted in loss of capacity of the drain. The rubbish content only serves as a blockade so it aggravates the situation” he explained.
Mr Adiepena said silting of the river is a natural phenomenon but when the banks of the drain is exposed and not properly grassed, materials fall into the drainage system to add to the deposits.
“So as part of our scope and project, we are not just to dredge but also beautify and green, landscape and all of that to enhance the look of the area,” he stated.
He stated that there can be a permanent fix to this drainage problem but that will require re-engineering and design of the Odaw drainage system, noting even after everything is done, “we cannot do away with the maintenance of the drains.