The period of the year between April to October constitute the rainy season of Nigeria. With the rain comes the recurring challenge of flooding in many states across the country.

Flooding occur when land which is normally dry is submerged due to overflow of water as a result of temporary rise in sea, river, stream and lake. It is a natural disaster which have been greatly aggravated by various man-made activities.

There are three main forms of flooding in Nigeria which are river flooding, urban flooding and coastal flooding. Floods could develop slowly over a period of few days or in a flash with no prior sign of rain.

In Nigeria, the geographical areas that are most prone to flooding include the following:

The low-lying coastal areas in the southern states with heavy annual rainfall.
The Niger Delta zone lying along the Niger-Benue rivers.
The floodplains around other major rivers.
Flat low-lying areas around Lake Chad

Causes of flooding in Nigeria

Rise in temperature resulting in intense precipitation, glacier melt, thermal expansion of the ocean with its associated consequence of rise in sea level and flooding of coastal areas.

The major cause of these conditions globally is climate change. In Nigeria, climate change is coupled with various human activities such as poor governance, poor drainage system, blocking of drainage channel through the dumping of waste and refuse, rapid industrialization, urbanization and population growth as well as exploitation of natural resources as in deforestation.

Flood can actually benefit nature so long as it occur away from human communities where it more often than not wreck havoc. River's water reach more areas above and below ground during flooding.

These water can be stored and utilized by people and nature. Flood filter out pollutants from rivers and support fertile areas of farming and other ecosystem.

The reproductive cycles of a number of species commences with flooding. New habitats that are homes to a number of birds, fish
and other wildlife.

Consequences of flooding

Floods are the most frequent natural disasters the world over affecting over 2.8 billion people and was responsible for over 200,000 death in about 30 years. According to a scientific report, between 1995 to 2015 alone, the lives of 2.3 billion people were affected by floods, so that floods account for 47 % of all weather-related disasters globally.

Flood has led to the devastation of many communities across Nigeria with thousand of lives lost and properties worth millions of dollars destroyed. Farm land, electricity, roads, railways and other social amenities particularly water supply have all suffered setback as a result of flooding.

Source

Infectious waterborne diseases are endemic, and a source of primary health concerns in the wake of flooding. Heavy rainfall increases microbial load of surface water by mobilizing and transporting pathogens present in the environment into water bodies.

Thus flooding is often associated with the outbreak of various waterborne diseases such as typhoid, paratyphoid, cholera, cryptosporidiosis, non-specific diarrhoea and rotavirus. Vibrio spp being the most common waterborne pathogen isolated after flooding.

Researchers have also proved that the outbreak of leptospirosis following flooding is due to lack of refuse collection and management leading to increase in rat population particularly in densely populated areas with poor sanitation and hygiene.

Cases of flooding

There have been numerous cases of flooding in Nigeria. The flooding that occurred in 2012 being the worst in 40 years according to the National Emergency Management Agency.

The flooding that occurred in 2012 was due to above normal rainfall in coastal region of the country. This was aggravated by the release of water from Lagdo Dam in Cameroon coupled with the fact that some rivers overflow their banks in some states.

During the notorious flooding of 2012, 33 out of the 36 states in Nigeria were affected, 363 people were killed while an estimated 2.1 and 7 million people were displaced and affected respectively.

One of the most frequently flooded cities in Nigeria is Ibadan, in Oyo State. Unlike the cities in the coastal region of the country, Ibadan does not possess the type of heavy rainfall regime that warrant these recurrent flooding. The most publicized and catastrophic of these flooding incidences occurred on the 31st of August,1980. It claimed 300 lives and rendered 50,000 people homeless.

Ibadan is the largest city in West Africa, and her recurrent flooding may not be unconnected to her growing population coupled with the mismanagement of her environment in the form of blockage of drainage, encroachment of floodplain occasioned by uncontrolled deforestation of the hill slopes among others.

Source

Dwellers in the flood plains of Lagos state live in constant fear each time it rains torrentially because they have learnt by experience that they may be rendered homeless or subjected to other humiliating forms of suffering. A classic example is the 1988 flooding that occurred when it rained heavily in Lagos for three days.

Curbing the menace of flooding in Nigeria

Early warning by agencies and bodies that are saddled with such responsibility is one of the most proactive measures that can be taken to forestall the menace of flooding in the country.

It is quite disturbing that the Nigerian Meteorological Agency had warned the country prior to the 2012 flooding incidence of the possibility of flooding that year due to above normal rainfall but their warning was not heeded by anyone.

It is also important that the nation wake up to the reality of climate change which necessitate the implementation of risk reduction strategies by government at all levels.

Equally important is the need to put to work contingency plan and emergency plan to both prevent and minimize the occurrence of flooding in the country.

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