Flood in Nigeria is a common environmental problem. In the wake of the flood disaster that plagued Benue state last week where thousands were rendered homeless, this article enumerates important facts about flood in Nigeria and why you should equip yourself with this information that can save lives and properties.
Flood is said to occur when a body of water moves over and above an area of land which is not normally submerged. It could also be seen as the inundation of an area not normally covered with water, through a temporary rise in level of stream, river, lake or sea viewed flood as a natural consequence of stream flow in a continually changing environment.
The occurrence of flood represents a major risk to riverside and floodplain communities, in addition to causing substantial impacts on the environment, including aquatic fauna and flora, and bank erosion.
Flooding is becoming an increasingly severe and more frequent problem in Nigeria. Unfortunately, the impact is more felt by the urban poor in such a way that recovery is unlikely to be achieved without external aid.
In other words, urban poor are most vulnerable to the impact of flood in Nigeria because they set up homes in the floodplains.
According to Action Aid (2006) four types of urban flooding can be recognized:
(a) Localized flooding which occurs many times in a year due to few and blocked drains;
(b) Small streams in urban areas rising quickly after heavy rains, but often passing through small culverts under
(c) Major rivers flowing through urban areas;
(d) Wet season flooding in lowland and coastal cities.
Flood in Nigeria occurs in three main forms, these are: River flooding, urban flooding and coastal flooding.
The heavy rainfall coupled with bad human activities in relation to the environment and lack of drainage infrastructure in most Nigerian cities has left hundreds of people distressed and homeless.
It should be mentioned that flooding in cities can contaminate water supplies and intensify the spread of epidemic diseases, diarrhea, typhoid, scabies, cholera, malaria, dysentery and other water-borne diseases.
Human activities such as rapid industrialization and urbanization, population growth, exploitation of natural resources and location of infrastructures exacerbate the occurrence of floods.
Floods are the most recurring, widespread, disastrous and frequent natural hazards of the world. It is worthy to note that all floods are not alike, while some floods develop slowly and last for a period of days; there is something called flash flood which can develop quickly, sometimes in just a few minutes and without any visible signs of rain.
Urban flooding has resulted in major loss of human lives; destruction of economic and social infrastructure such as water supply, electricity, roads and railway lines (means of livelihood).
According to UN-Water (2011), worldwide, there has been rapid growth in number of people killed or seriously impacted by flood disasters. Indeed, the amount of economic damages affects a large proportion of people in low-lying coastal zones or other areas at risk of flooding and extreme weather condition.
UN-Water (2011) also clarified that floods, including urban flood is seen to have caused about half of disasters worldwide and 84% disaster deaths in the world was attributed to flooding.
Common and recurrent phenomenon of flood in Nigeria occurs on a regular perennial basis in some parts of the nation.
However, the following geographical areas suffer from the hazard more than others in Nigeria:
(a) Low-lying areas in the southern parts of the nation where annual rainfall is very heavy.
(b) The Niger Delta zone
(c) The floodplains of the larger rivers of the Niger, Benue, Taraba, Sokoto, Hadeja, Cross River, Imo, Anambra, Ogun, Kaduna etc.
(d). Flat low-lying areas around and to the south of Lake Chad which may be flooded during, and for a few weeks after the rain.
Because of its disposition as flat, low-lying swampy area of alluvial deposition across which the tributaries
of the Niger meander, the Niger Delta is by far the largest single area subject to annual flood in Nigeria. It is a natural reservoir for the Niger-Benue catchment area and its inefficient outlet to the sea. Its rivers are bordered by levees, and when these rivers are in flood, the levees are over-topped and extensive areas are submerged.
The zone is subject to two types of flood, the floods of the rainy seasons which are the result of rainfall within Nigeria and especially rainfall in the delta area itself which ranges from 2000mm to 4000mm per year and is concentrated in few months.
The other type of flood is the river flood, almost all of which are caused by water coming from as far as the Fouta Djallon Highlands in Guinea. The water is primarily the runoff from the previous year’s rainfall on these highlands slowly making its way down to Nigeria.
Almost all parts of the Niger Delta, with exception of the northern parts, suffer flooding at one time of the year or the other. Town, villages and agricultural lands in the Sagbama and Yenagoa areas in Balyesa state are often affected. Also, often affected are parts of the riverine areas of Edo, Delta, Cross River and Akwa Ibom states.
In more recent years, 2011 and 2012 appears to be the worst incidence of flood in Nigeria with a lot of reported cases indicating how flood menace ravaged affected states of the country when water from the Lagdo Dam in Cameroon was released.
Although the Nigerian Meteorological Agency (NIMET) had alerted Nigeria that there would be an above normal rainfall in strategic parts of the country which might lead to flooding incidents in 12 states of the federation, yet nobody gave consent to that warning.
Thus, flood in Nigeria is a serious issue requiring the attention of all stake holders aimed at preventing and remedying its adverse effects which threatens human existence.