Annual floods in Accra: An engineering failure (June, 10, 2015) Front

An environmental economist has said that any effort at curtailing the perennial flooding in Accra will yield very little result if the deficiency in the construction of the Odaw drains is left unresolved.

Mr Kofi Owusu Bempah observed that Accra’s flood-prone areas were located within the catchment of two streams that emptied into the Odaw River from Caprice.

According to him, the drains constructed to contain the water from the two streams were the same size as the Odaw drain, adding that “any time it rains heavily upstream and the two streams get flooded and empty into the Odaw River at Caprice, the Odaw overflows its banks, causing serious havoc to lives and property”.

“If the volume and the force of the water are twice as much but the gutter size is not twice as much, at a certain level this will cause a spill. That is what we are experiencing now,” he said

Expanding the Odaw drain

In an exclusive interview with the Daily Graphic in Accra last Monday, Mr Bempah suggested to city authorities and the government to consider expanding the Odaw drain from Caprice to the sea.

To him, what was technically feasible was for the government to engage engineers to look at the possibility of digging the drains between 10 and15 feet deeper at the confluence of the two streams at Caprice right into the ocean.

“This will make it easy to remove and clean the drains and also make it difficult for people to throw in garbage,” he added - See more at: http://graphic.com.gh/news/general-news/44408-annual-floods-in-accra-an-engineering-failure.html#sthash.rXdCgyXc.dpuf

“This will make it easy to remove and clean the drains and also make it difficult for people to throw in garbage,” he added - See more at: http://graphic.com.gh/news/general-news/44408-annual-floods-in-accra-an-engineering-failure.html#sthash.rXdCgyXc.dpuf

According to him, if that was done, the flow of the two streams into the Odaw River would be like a fall, thereby preventing the river from overflowing its banks, even in the event of any heavy rain, as happened on June 3, this year.

“When you want to absorb the flood without allowing it to break the embankment of the drains, you need to dig further, so that where the two drains meet becomes like a waterfall,” he said.

The June 3 torrential rain caused floods that brought Accra to its knees, with unimaginable loss of lives and destruction of properties.

At least 150 fatalities were reported in the aftermath of the floods in a disaster that has been described as the worst in the country’s history after the May 9, 2001 Accra Sports Stadium disaster.

Flood-prone areas in Accra

A map of the city provided by Mr Bempah outlined areas such the Mallam Junction, Sakaman, Pambrose Salt, Mpoase, Glefe, Agege, Gbegbeyise and Mamprobi in Accra West as flood prone.

Similarly, in Accra East, part of Korle Bu, Alajo, parts of Accra New Town, the North and South Industrial areas, Awudome, parts of Adabraka, Kantamanto, Ussher Town, Korle Gonno, James Town, the Osu Castle and its immediate surrounding areas, the South La Estates, the Trade Fair site and its immediate surroundings, Teshie, especially Camp 2, Wajir and the Whitller Barracks are areas likely to flood.

Those areas aside, he stated that areas that had rivers or huge storm drains were also prone to flooding if there was no effective drainage system.

Accra’s problem

According to experts, Accra, which is sited on a low-lying area, experiences flooding annually mainly because of the haphazard construction of houses, especially on water courses, the poor drainage system and a poor waste management challenge that leads to residents turning drains into refuse dumps.

In 2011, floods in the country resulted in the death of more than 30 people nationwide, with 15 victims in Accra, in addition to the destruction of property running into millions of cedis.

Similar incidents were recorded in 1968, 1995,1997, 1999, 2001, 2010, 2013 and 2014.

While almost everybody agrees that the dumping of refuse into drains is part of the problem, opinions are divided over the resolve by the government and the city authorities to demolish buildings on water courses.

While public opinion is swayed in favour of demolition, there are others who hold the view that the various metropolitan and municipal assemblies in the city are to blame for issuing permits or looking elsewhere while people built haphazardly.

However, Mr Bempah was of the view that the demolition of buildings might not necessarily be the option, since areas where the demolition would take place could not be left vacant.

“What we need is an effective drainage system that addresses the challenges of the city as far as its topography is concerned,” he said.

The Netherlands example

Citing Amsterdam as an example, he said in areas where people lived below sea level or in low lying areas, what was done was the construction of underground drains to carry water away and not open drains.

According to The Guardian publication of February 16, 2014, The Netherlands learnt from past mistakes – a 1977 report warning about the weakness of the River Dykes was ignored because it involved demolishing houses.

It took floods in 1993 and again in 1995, when more than 200,000 people had to be evacuated and hundreds of farm animals died, to put plans into action to deal with floods — houses and fields were sacrificed to a flood management scheme.

Close open drains

In Ghana, open drains are everywhere and all storm drains in Accra are left open, making it easy for residents who are out of the remit of waste management companies to dump refuse into them.

That situation results in the storm drains particularly being choked ahead of the rainy season.

The way out, Mr Bempah said, was for the authorities to consider putting slabs that could be lifted by forklift on the drains.

“This will make it easy to remove and clean the drains and also make it difficult for people to throw in garbage,” he added

mental economist has said that any effort at curtailing the perennial flooding in Accra will yield very little result if the deficiency in the construction of the Odaw drains is left unresolved.

Mr Kofi Owusu Bempah observed that Accra’s flood-prone areas were located within the catchment of two streams that emptied into the Odaw River from Caprice.
According to him, the drains constructed to contain the water from the two streams were the same size as the Odaw drain, adding that “anytime it rains heavily upstream and the two streams get flooded and empty into the Odaw River at Caprice, the Odaw overflows its banks, causing serious havoc to lives and property”.
“If the volume and the force of the water are twice as much but the gutter size is not twice as much, at a certain level this will cause a spill. That is what we are experiencing now,” he said

Expanding the Odaw drain

In an exclusive interview with the Daily Graphic in Accra last Monday, Mr Bempah suggested to city authorities and the government to consider expanding the Odaw drain from Caprice to the sea.
To him, what was technically feasible was for the government to engage engineers to look at the possibility of digging the drains between 10 and15 feet deeper at the confluence of the two streams at Caprice right into the ocean.
According to him, if that was done, the flow of the two streams into the Odaw River would be like a fall, thereby preventing the river from overflowing its banks, even in the event of any heavy rain, as happened on June 3, this year.
“When you want to absorb the flood without allowing it to break the embankment of the drains, you need to dig further, so that where the two drains meet becomes like a waterfall,” he said.
The June 3 torrential rain caused floods that brought Accra to its knees, with unimaginable loss of lives and destruction of properties.
At least 150 fatalities were reported in the aftermath of the floods in a disaster that has been described as the worst in the country’s history after the May 9, 2001 Accra Sports Stadium disaster.

Flood-prone areas in Accra

A map of the city provided by Mr Bempah outlined areas such the Mallam Junction, Sakaman, Pambrose Salt, Mpoase, Glefe, Agege, Gbegbeyise and Mamprobi in Accra West as flood prone. Similarly, in Accra East, part of Korle Bu, Alajo, parts of Accra New Town, the North and South Industrial areas, Awudome, parts of Adabraka, Kantamanto, Ussher Town, Korle Gonno, James Town, the Osu Castle and its immediate surrounding areas, the South La Estates, the Trade Fair site and its immediate surroundings, Teshie, especially Camp 2, Wajir and the Whitller Barracks are areas likely to flood.
Those areas aside, he stated that areas that had rivers or huge storm drains were also prone to flooding if there was no effective drainage system.

Accra’s problem

According to experts, Accra, which is sited on a low-lying area, experiences flooding annually mainly because of the haphazard construction of houses, especially on water courses, the poor drainage system and a poor waste management challenge that leads to residents turning drains into refuse dumps.
In 2011, floods in the country resulted in the death of more than 30 people nationwide, with 15 victims in Accra, in addition to the destruction of property running into millions of cedis.
Similar incidents were recorded in 1968, 1995,1997, 1999, 2001, 2010, 2013 and 2014.
While almost everybody agrees that the dumping of refuse into drains is part of the problem, opinions are divided over the resolve by the government and the city authorities to demolish buildings on water courses.
While public opinion is swayed in favour of demolition, there are others who hold the view that the various metropolitan and municipal assemblies in the city are to blame for issuing permits or looking elsewhere while people built haphazardly.
However, Mr Bempah was of the view that the demolition of buildings might not necessarily be the option, since areas where the demolition would take place could not be left vacant.
“What we need is an effective drainage system that addresses the challenges of the city as far as its topography is concerned,” he said.

The Netherlands example

Citing Amsterdam as an example, he said in areas where people lived below sea level or in low lying areas, what was done was the construction of underground drains to carry water away and not open drains.
According to The Guardian publication of February 16, 2014, The Netherlands learnt from past mistakes – a 1977 report warning about the weakness of the River Dykes was ignored because it involved demolishing houses.
It took floods in 1993 and again in 1995, when more than 200,000 people had to be evacuated and hundreds of farm animals died, to put plans into action to deal with floods — houses and fields were sacrificed to a flood management scheme.

Close open drains

In Ghana, open drains are everywhere and all storm drains in Accra are left open, making it easy for residents who are out of the remit of waste management companies to dump refuse into them.
That situation results in the storm drains particularly being choked ahead of the rainy season.
The way out, Mr Bempah said, was for the authorities to consider putting slabs that could be lifted by forklift on the drains.

- See more at: http://graphic.com.gh/news/general-news/44408-annual-floods-in-accra-an-engineering-failure.html#sthash.rXdCgyXc.dpuf