Causes and health implications of flooding


What is flood

Flood is a large amount of water covering an area that is usually dry; the heavy rain has caused flood in many part of the country, it is generally understood that excessive flooding is one of the visible features of communities or towns that are situated in low topography, while poor draining system is one of the features that causes high flood in topographical area. However, most of the flood usually occurs in the coaster regions, flood can be naturally caused e.g. high rainfall, man can also contribute to the causes of flooding in a locality by using public drains as waste disposal facilities. This causes blockage of the drains thereby loading to flooding.

Secondly, illegal constructions of buildings on natural waterway by obtaining permission from corrupt town planning officers.

Thirdly, lack of maintenance of drainage by either government or the local inhabitants also contributes to flooding. All these causes of flooding serve as a menace to the health of human being and its environment. Therefore, it is well understood that the causes of flood as well as its implication on the people is based on both natural and artificial (human activities) causes.

Types of flood

According to Hawkins floods are categorized into the following;

  • Coaster Floods.
  • Flash Floods.
  • Harmful Floods.
  • Useful Floods.

Coastal floods: Low lying areas on the coastal are occasionally flooded by usually high tides furnished up by strong winds towards the shore. Another cause of coaster flood is a giant sea waves called Tsunamis, which is caused by undersea earthquake or volcanoes. Coastal flooding could drive much water into the coastal area to cause damages to life and property like Tsunami of 2004.

Flash floods: The most spectacular and rapid flood are flash flood caused when thunderstorm or hurricane bring short heavy burst of rain over the mountain, they rise and fall rapidly with little or no advance warning. When this happens, the water level in the mountain stream rise very quickly and send walls of water rushing at great speed into valley below. In many desert areas the ground is backed hard by the hot sun, so that when heavy rain falls, the water rushes over the surface and fill gullies or water channels and dry water beds in minutes.

Harmful floods:  This type of flood not only damage properties and crops, but also endangers the lives of human and animals on slopes. Furthermore flood water can wash away soil that clogs river, stream and destroys that spawning grounds of fish, long lasting flood delay traffic, makes sewer over flow and damage electricity and telephone systems.

Useful flood: Despite the fact that there is harmful flood is also useful flood. Flood caused by river can be useful; when a river flows, it dumps mud and sand over the land. These make a very fertile soil called alluvial soil; Ancient Egypt become a wealthy Country because of the river Nile flood rain, every year the Nile flooded and brought water to land that otherwise add alluvial soil to river banks there, people grew cotton, corn, rice and vegetable.

Causes of flood

According to Park (2008), flooding is by both naturally and artificial factors (human activities).

Natural causes of flooding

The most natural cause of flooding according to Olorunda (2007), is as a result of excessive heavy and prolong rainfall, Storm spring tides and low atmospheric pressure. Examples of area where this has occurred include (Zech Republic and Poland in July, 1997, Ogunpa in Ibadan in 1988 and 1980, Lisatuwa and Aogo Ondo State in 1985 and 1988, Gombe 2004, Anambra in 2004, Ala River in Akure 2004 etc.

According to Watch Tower Bible and Tracts Society (2008), most flooded area of the earth is as a result of topographic arrangement by natures. Another suggestion cases of flooding according to (Louis et al., 2008) in which observed that a projected sea-level rise of about one meter this Century mould trigger flooding over about (8000C) square kilometre Olorunda (2007), also added that naturally flood is a result of high frequency of rainfall in town and cities that are in low topographic area.

Artificial causes of (factors) of flooding

This is a result of human’s improper use of utilization of the physical environment, Marshal (2007), states that human activities contributes immensely to flooding especially in the Urban area.

Olurunda (2007), states that example of artificial causes of flooding in Urbanised centres as;

  1. Blockage of drainage system meant for free flow of water, indiscriminate dumping of refuse into rivers and water courses which could lead to blockage of water channels thereby causing flooding.
  2. Deforestation activities exposing the soil to the intense force of rainfall causing erosion and secondly leading to flooding erosion.
  3. Open dumping is another cause of flooding Olorunda (2006), when the dumps are filled and rainfalls, part of the refuse are eroded to fill the public drains, thereby leading to flooding. He also added that public drains of towns and cities used as substitutes for toilet and waste facilities can cause blockage of the drains thereby resulting to flooding.

Ogberahwe (2005), states that it is a known fact that whenever there is a case of over flooding individuals in the society (especially Nigerian) pay only specific attention to the blockage of drains gutters. They forget their social activities that can aid this situation, which the building of houses along natural water routes, as a key factor of flooding.

Implications of flooding

According to Olorunda (2008), flood causes havoc and damages the environment and the populace. He then went further to state that flood damages ranges from destruction of properties, farmlands, electrical installation building and structures to displacement of persons and lost of lives.

Damages caused to building and properties are usually terrible to estimate. Major examples in Nigeria were the Lagos bar beach flood in 1984, 1988 and 2002 respectively as well as the Indiegore flood of 1981 in Abia, Jigawa flood in 2001, Sokoto flood 2010 disaster and other across the country. Expensive damages are also done to agriculture and agricultural products by flood; in Nigeria for example, 650,000 and 440,000 hectares of agricultural land are flooded annually in the Niger Delta and the North Western part of Nigeria respectively, the inhabitants of this area were forced to abandon their farmland and even the entire village where flood comes.

According to Unuraye (2005), flood not only damage properties and endanger the life of human and animals but have other effects as well as rapid run-off causes soil erosion as well as sediment deposition problems dam drains, spawning grounds for fish and other wildlife habitats are also destroyed. High velocity current increase flood drainage, prolong high floods delay traffic and interface with drainage and economic use of other structure with flood ways are damage and navigation and hydroelectric power are often impaired. This article also states that financial losses due to flood commonly amount to millions of naira each year in the developing Countries, however many thousands of people die each year from flood (Watch Tower Bible and Tract Society, 2008).

According to Vincent (2009), over two thousand farmlands, School, Churches, Houses and Markets in Ndokwa West Local Government Area of Delta State have been ravaged by flood and its environs which includes Onyia, Umutu, Aboh and almost every farm in the Beneku has been  destroyed by flood.

Patrick (2009), reports that flood have taken over the bridge head of the Orogodo River in Agbor thereby leading to erosion which has caused bridge collapsing.

Michael (2009), commented that the problem of gully erosion in Agbor has become a source of great concern to resident of Agbor and that 90 percent (%) of houses along the coastal are of the Orogodo River are under severe threat due to the effects of flood in the area.

Mirabel (2008), wrote that the flood in Aboh Community in Ndokwa East Local Government Area caused the entire Community greater distress and economic loss and making living to become expensive unaffordable in the area. The situation they noted, resulted in the untimely flooding of crops such as plantain plantation, water yam, cassava, sweet potatoes, pepper among others. In the area, animal trap-fence measuring 3-5km where also covered due to effect of flood which causes scarcity of bush meant in the community.

Health implication of flood on human

Flooding usually brings or leads to outbreak disease like Malaria fever, Dysentery, Cholera, pneumonia, common cold etc. (Park, 2008), people also die as a result of flood, injured and lost of their homes as a result of flood. In China the Yangzi River flooded in 1998 and 1999, as it had done many times before but in these years, thousands of people died. They were worse than usual because people had cut down trees in upper parts of the river.

Implication of flood on the government and its economic effects

The government and wildlife is at risk at when damage to businesses. According to John (2007), flooding can make the environment unfavourable for people especially drivers disrupting of public and personal transport by cutting off roads and railway leading to traffic congestion.

According to Vincent (2007), there has been great economic loss and damages caused by flooding in many parts of the county each year. Take for instance the flood in Anambra State and the damage it caused as stated in the pointer newspaper of 23rd September 2009 that thousands of naira meant for economic development in the Local Government have been wasted on flood control.

According to Irrifere (2008), building in flooding areas in Ughelli lose their economic value by making them un-aesthetic especially to pipeline and Urhie Streets. Finally, after flooding resources impute by Government for aiding or reconstructing and resisting of the great damages caused by flood, has loose to the economics of the society at large.

Prevention/control of flood

Flooding in village, towns and cities in Nigeria has become so worried. Some to people living in the Country said that urgent attention should be taken to curb it which must be designed and executed.

Paul (1998), observed some ways of reducing or stopping river floods these ways includes.

  • In some places people build high banks called caves to stop the river flooding nearby homes and land.
  • Another way to reduce the risk of flooding is to use a special kind of ship called a Dredger, to remove mud and sand from river bed. This deepens the river so that it can hold more water.
  • Straightening the lower stretches of a river can also help to carry flood water out to sea faster.
  • Sometimes, a relief channel can be dug to divert some of the flood water away from the main river.
  • Planting trees steep slopes also slows the rate at which water flows.

There are three major measures for combating flooding menace in man’s environment.

According to Olorunda (2007), they are;

  1. Flood adjustment.
  2. Flood prevention.
  3. Flood minimization

There is a point we must all note and that is the fact that since flood is a natural phenomenon, it is not possible for us to have an absolute control measure for flood.

  • Flood adjustment

Involves accepting the loss, Public relief and other emergency action taken immediately after any flood incidence; Immediately a flood disaster occurs, the victims must first accept the loss arising from its occurrence after which what follows establishment of a relief fund by the government, NGO’s and Private individuals.

  • Flood prevention

These are efforts that are meant to prevent flood hazards rather than curing it, such efforts include modification of cropping practices, reforestation, terracing, contour sloughing and disallowing bush burning. Other are the proper enforcement of all town planning and environment laws in construction of building layout, mapping, construction of drainages and other channels for the free flow of water as well as prosecution of offenders caught dumping of refuse on water Course and channels and all laws regulating tree falling and deforestation activities.

Furthermore, enforcement of appropriate setback legislation on river course and drainage and there must be minimal or no cultural and political pressure on the officer of the relevant enforcement agencies.

  • Flood minimization

Flood minimization is mainly concerned about the river and streams channel and the purpose is to control the flood and minimized the damage it caused by regulating it flow or diverting it away from damaging structures or properties.


In the cause of this seminar work the researcher was able to identify the cause and health implication of flood on the environment and its inhabitants.

  • That lack of standard drainage system contributes to flooding in the environment.
  • The nature of the topography contributes to excessive flooding.
  • That people behavioural attitudes towards indiscriminate waste disposal contribute to the problem of flooding.
  • That flooding has health implication among the people living in the environment.


In order to reduce the menace of flood, (the researchers recommend that road construction should accompanied by building drainage that are not constructed alongside the road, apart from leading to flooding, the lifespan of such road are reduce. Government should enforce the relevant regulation and make sure that contractors construct road according to specification in the area where flood fall out of the environmental factors. A comprehensive master plan should be work to tackle the menace. The government should apply short term measure to combat the scourge and after rain, a teams of expects should assemble to find lasting solution to the annual devastating effects of flooding. In view of all this, all human activities have to be harmonized in the line with a friendly environment and learn to cope with flood and other environmental hazard.  Environmental education and awareness campaign in the human exploration of the environment; thus if effectively carried out will make them to obey the law guiding the use of natural resource and promoting friendly environment safe for all to live.


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Mirabel, I. (April 8th 2008). Natural Disaster . Point Newspaper. Vol 63(15):6.

Olemefore, O. E. (2002). Environmental protection Benin City; Gift Print Associates.

Ogberhahew J.O & Aibor M.S (2006). A Technical Handbook of Environmental Health in the 21st Century for Professionals and Students Lagos: Divine Favour Publishers.

Olorunda, O., David, O., Samuel, K., Mercy, O. & Adama, S. (2007). Monitoring and Modelling Techniques of Environmental Pollution (1st ed). Akure: His Mercy Publisher.

Park, K. (2006). Textbook of preventives and social medicine (19th ed) India: Benard.

Patrick, N. (June 10th, 2009). Flood Menace.  Pointer Newspaper. Vol 55 No 6.

Unuraye, l. O. & Olojoba, A. O. (2005). Fundamental of Industrial and Environmental Health (1st ed) Ughelli: Ama-Ohoror Printing Press Coy.

Watchtower Bible and Tract Society (August 4th 2008). Natural disaster. Are they getting worse? Pennsylvania: Awake.

Watchtower Bible and Tract Society (August 8th, 2009). What’s happening to the Weather? Pennsylvania: Awake.

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