The current flood, which has affected about 33 out of the 36 states, is arguably one of the worst in Nigeria since 2012. It has compelled some foreign donors to come to the aid of the country.
Already, the flood has led to the death of over 600 persons, with over two million persons displaced.
About 200,000 homes have been totally or partially affected, while about 3332,327 hectares of land have been completely damaged.
The humanitarian crisis and psychological stress the disaster has brought to many are yet to abate in states like Bayelsa, Kogi, Anambra, Delta, and Rivers.
There have been viral pictures of houses that were completely submerged up to the roof.
Overall, there is a growing concern that some of the submerged houses may no longer be safe for habitation because the structural integrity of the buildings may have been compromised by the flood water.
Already, in Kogi State a few days ago, there were reports that five persons died when a flooded building in which they took shelter collapsed. They were said to have taken cover in the building, waiting for the flood water to recede when the incident happened in Ayah, Ibaji Local Government Area of the state.
Some experts, who spoke to our correspondent, stressed the need for the government to look into the danger such flooded buildings could portend. They noted that the travails of the displaced persons were regrettable, but that there might be a need to examine the flooded houses before they would be re-occupied by their owners.
Speaking on the issue, a former President of Building Collapse Guild, Kunle Awobodu, stated in a telephone interview with our correspondent that water could be regarded as the greatest enemy in the engineering world, as it could weaken the elements of buildings.
He said, “When buildings are submerged in flood, they are exposed to lots of chemical reactions because the flood water itself is full of impurities that might later infiltrate the elements in the building, thereby igniting chemical reactions. This is why no matter the amount of painting carried out, the wall of such buildings involved still peels off. Preventing a building from being submerged is better.
“Also, it is time to test the durability of materials used in the construction of buildings. Once durable materials are used, any building submerged by the flood will remain undisturbed and undervalued. If the materials used in the construction of a building are not durable, it is just a matter of time for such buildings to collapse.”
He stressed the need for relevant authorities to ensure that people did not build on flood plains so as to minimise the incidence of flooding.
He added, “In addition, this flooding period is a time to caution us not to build on the flood plains, across canals, and not to block drainage systems. I received a message from one of our members in Adamawa State who lamented that most of the buildings in their town collapsed due to the flood. Also, his family home already harbours some cracks.”
Awobodu explained that once the foundation had been subjected to serious tension, it might not be able to carry the weight on it and could gradually give way.
Awobodu noted, “Once the soil, which is the national foundation of a building, is eroded, the artificial foundation, which is the constructed building, will gradually give way.
“The government should show interest and ask themselves if the submerged buildings would still be able to serve their purpose and whether or not they would be safe for the inhabitants?”
He concluded that there might be a need to engage professionals to inspect the submerged buildings.
He added, “It is very important that after flooding, buildings should be re-examined to re-ascertain their suitability for habitation. Once the weak areas have been discovered, it is pertinent to ask if they should be renovated or pulled down, so that it will not be a sham posing danger to the inhabitants.”
Similarly, the President of the Building Collapse Prevention Guild, Eddy Atumonyogo, said buildings with good foundations would have no problem but those with weak foundations might have issues after the flood water receded.
He stated, “There has to be a structural re-evaluation of buildings once the flood recedes. Once buildings are submerged, people are completely evacuated from the lowlands. Then, after the flood recedes, experts should be sent to conduct structural integrity tests to ensure that once inhabitants of such affected buildings return, they return to safety, and not to danger.
“Also, in situations like this, if we have a government that cares, they should have shelters to provide safety for affected persons, before they are able to pick up their lives. Nigerians have been sorting themselves out, and that is why there is so much crime because those who cannot sort themselves out are involved in all forms of evil. The government should have a shelter plan for these kinds of situations.
“Also, the government has to clear the drains and canals, and when buildings are built along the canal and drainages, thereby blocking the flow of water, such buildings should be removed.
“Also, there is a need for serious education for people to stop blocking the canals and drainages. This would have solved about 60 per cent of the problem.”
The Chairman of the Nigerian Institution of Building, Lucky Isename, pointed out that buildings constructed in the 1960s were standing strong, while those under construction were collapsing due to malpractices and avoidable causes.
He added, “The causes of this range from shady malpractice to human errors, corruption, and non-adherence to the minimum standard of construction.
“It is pertinent to note that there is no way the blocks of submerged buildings will not absorb water, and once it’s soaked, the water would weaken those blocks thereby making the blocks lose strength and become a danger waiting to happen.
“Non-destructive tests have to be carried out on the submerged buildings to ascertain habitation. Importantly, it is the responsibility of the government to educate the masses on the danger posed by such buildings after the flood recedes, especially if no test was carried out on them.”
Also, speaking in an interview with The PUNCH, a structural engineer, Olatunbosun Adaramola, said the fate of submerged buildings depended on the quality of the construction.
He said, “Most of these buildings were not constructed by professionals in the construction industry. Many of them were constructed using inferior/substandard materials, which would make the building fail in situations like this.
“This explains the reason why professionals and regulatory bodies in the built industry advise people to always engage the right professionals, and not leave their construction in the hands of half-baked artisans who claim they can do it because they have handled one or two small-scale constructions.
“Importantly, it depends on the integrity of the materials used in constructing the buildings. We understand the economic situation in the country and how it is affecting the cost of materials, especially building materials. However, this should not be a reason to use substandard materials to build houses that people would live in, do business in or even use as storage facilities.”
He stressed that if the right materials were used, there would be less panic over the fate of such buildings after the flood recedes. “Also, if the right building methodology was adopted in constructing these buildings, the damage to them would not be as much as when wrong methods were used to build them,” he added.
Adaramola urged the government to empower agencies in the built environment to move around and carry out integrity tests on all the affected buildings. He said the government should also engage professionals for the task given the high number of buildings affected. “It will be a lot for only government agencies to do it alone,” he noted.
The engineer also stated that the government should investigate houses located on flood plains and demolish them so that if flooding occured again, the effect would not be of such great magnitude. He added that more drainage systems should also be constructed to decongest existing drainage systems.
Also speaking, the National President, Nigerian Institute of Builders in Facility Management, Dr. Akinsola Olufemi, said the foundation of submerged buildings could be impaired to carry the load of the building. He said if nothing was done, the building could become a death trap.
Olufemi said, “Any building opened to water ingress, that is the wall fabrics are soaked in water, would begin to produce molds, giving room for a sick building syndrome. Sick building syndrome connotes that people that would inhabit the submerged house once the flood recedes would be falling sick because the air circulation in that house would have been contaminated.
“A pregnant woman in that building would be living there under serious health hazard, leading to inadequacy in breathing. However, when the water is completely removed, it is expected that the building will be treated in a way that all the water soaked in the wall fabric is removed before people begin to live there.”
He noted, for example, that the Lagos State Government had announced that people in flood plains in Ikorodu, Ketu, Owode-Onirin, and some other areas should be prepared to move out because of the dangers associated with submerged buildings.
He said this was always the case when water was released from the Oyan Dam in Ogun State, flooding Ojota, Ikosi, Ketu areas, and leading to the collapse of some buildings.
Olufemi stated that for buildings submerged to the roof level, there was a higher possibility of the wall failing and that even after the water receded, there would be cracks on the walls of such buildings.
He added, “In this case, it is pathetic because where the water should be flowing to is where the water is coming from, hence, it may not be very easy for the government to do much now.
“Normally, if the government knew the dangers that would result from this flooding, they ought to have designed another dam that could capture the excess water from going into the people’s homes, which they did not do.
“It is the responsibility of the government to take stock of the victims affected and compensate them. In addition, areas prone to dangers should have special designs and construction. What the government requires from areas prone to flood is different from what is required in normal areas, to obviate dangers that may come with such disasters.”
