Introduction
The world health organization (WHO), (2001), Defines disaster as an event that occurs when significant numbers of people are exposed to hazard to which they are vulnerable with resulting injuries and loss of lives often combined with damage to property and livelihood. Examples of disasters include drought, wind storm, tropical cyclones, extreme temperature and foods etc.
According to sally, (2005), flood is a large amount of water covering an area that is usually dry. The European Union (EU) on flood directives (2012), define flood as a covering by water of land not normally covered by water. Flooding may occur as an overflow of water from water bodies such as rivers or lakes in which the water overtops or breaks leaves (a low wall built at the side of a river to prevent it from flooding) resulting in some of that water escaping its usual boundaries or may occur due to accumulation of rain water on a saturated ground around an area flood.
Types of floods disaster
There are several types of floods as stated by Alexander (2002), which includes the following:
- Flash floods: These are floods that usually result from intense/heavy rainfall over a relatively small area of land that is already saturated from previous precipitation (rainfall). Flash floods are characterized by a rapid rise of fast moving water which is extremely dangerous. A common speed for flash floods can move rocks weighing almost a hundred pounds. Flash floods carry debris that evaluate their potential to damage structures and injure people. Flash flood is a flood of water caused by heavy rain.
- Coastal floods: These are floods that occur along the edge of ocean and it is driven predominantly by storm surges such as wave damage. This kind of flooding is usually connected to hurricane, tsunami or tropical storm and it results to death and damage of structures.
- Ice jam flooding: In this is the type of flooding; water are often frozen covering a large volume of water in what is known as a dam and when water began to pill up spilling over the plains, the wall of the ice jam breaks and fast moving water rushes downstream much like a conventional flash flood, destroying objects in its part. The water carries huge chunks of ice which increase damage to surrounding structures.
- Urban flooding: This is the inundation of land or property in a built environment particularly in more densely populated area caused by rainfall overwhelming the capacity of drainage system such as storm sewers. It is sometimes triggered by events such as flash flood or snowmelt.
- Catastrophic flooding: This type of flooding is usually associated with major infrastructure failure such as the collapse of a dam, but they may also be caused by damage sustained in an earthquake or volcanic eruption.
Causes of flood disaster
Adeloye and Rustum (2011), analyses the causes of flooding problems being encountered to recommend sustainable management solution to them. They say that some primary causes of flooding are
Discharge of huge volume of water in a short span time: This is the type of flood which happens when there is a discharge of water in a short span at a rate such that the water cannot be carried away from the scene of the discharge. Some possible reason for such huge discharge of water could be;
- Very heavy rainfall in a short span of time, it could be noted that the amount of rainfall itself is not a sufficient cause but the duration the rain is receive equally important.
- Break in levy, dam etc.
- Very high tidal waves.
Human encroachment: This includes deforestation, building in water way and water cause (filling of stream and swamp with earth and erecting building).
Increase urbanization industrialization
Inadequacy of storm drainage system/choked drainage system.
Indiscriminate disposal of waste on streets and roads.
Effects of flood disaster
It is on record that 70% of the earth’s surface is covered by water. Equally true is the fact that humans, animals and plants need specific amount of water to survive but food however, is the unusual present of water on land to a dept which affects normal activities (WHO, 2001).
Wisner, Blaiker, Cannon, and Davis, (2002), state that flood causes the following effects on lives and properties.
Displacements of humans and animals from their settlements.
Creation of hunger and starvation due to destruction of farm and farm products with water.
Rendering of the victims as refugee in their fathers land.
Malnutrition, lack of potable water.
Restriction to normal activities of the people in dispora.
Shortage of food supply.
Driving wild animals from forests and wet land into villages, towns and cities that devour humans as a result of being displaced from their original habitat.
Lack of water: It is irony that a disaster that mean water everywhere result in lack of water to drink and sanitation. Lack of proper (wholesome) drinking water and sanitation can lead to wild spread of disease e.g cholera.
Drowning: People, livestock, goods etc might get drown.
Wild spread damage to structures.
Lack of utilities: Utilities services might have to be turned off for the fear of electrocution as there is water everywhere.
Death.
Prevention/control of flood disaster
Flood control refers to all methods used to reduce or prevent the detrimental effects of flood water. The method includes planting vegetation to retain extra water, terracing hillsides, to slow flood downhill and construction of flood ways (manmade channels to divert flood water). Other technique includes construction of levees, lakes, dams, reservoir etc. (Adeloye and Rustum, 2011).
Wisner et, al (2004), states that sometimes it is not easy to prevent a flood even if we know that it is about to get flooded. However, there are certain actions that can be taken to reduce the impact significantly or to reduce the possibility of flooding.
Keep the drainage system clean: This allows water to be carried down very fast. Choked drain causes a significant reduction in the ability and speed of water to be drained away. This is a major cause of urban flooding. Drains can be choked/blocked due to the throwing of solid waste (plastic, paper etc) inside storm drains.
General cleanup of streets: This is also important if we are to prevent flooding because as rain water falls down the street, it rushes into the storm drain. Therefore, if the streets are not clean, the rain water trying to get into the drain carries solid waste into the drain with itself which then obstruct the flow of water by the draining system.
Afforestation: forestation helps in binding the loose soil. The most major impact of this is as flood water races through; it might take loose soil with it which can lead to blockage of drainage. On the other hand, trees will prevent soil from flowing with water as the roots of the trees will act as binding force.
Afforestation also reduces the impact of flowing water such as over flowing rivers. As water charges forward, its speed is reduce to some extent due to the resistance offered by trees thereby reducing structure damage due to weakening in the force with which water hit various structures.
Rain water harvesting system: As more rain water try to flow down the drains, it put much more stress on the drainage system. Instead, if there are several rain water harvesting system the rain water falling in that much area will try to go to the sub soil of the region locally rather than straining the drainage system. The lower the amount of water trying to go through the drainage system, the easier it is for the drainage system to drain off the water.
The roles of environmental health officer in flood management
There are several agencies responsible for flood management but I am focusing on the roles of environmental health officers which include the following as stated by Wisner and Adams, (2002).
- Identify/recognize potential threats and hazards.
- Assess health risk.
- Determines priorities and recommend action.
- Develop objects, determine priorities and intervention strategies.
- Ensure people are consuming wholesome water.
- Ensure that food meant for consumption by flood victims are not contaminated to prevent the spread of food borne diseases.
- Ensure people have water for personal hygiene.
- Ensure that waste are properly managed to prevent outbreak of disease.
Bankoff and Hihorst, (2003). States that the role of environmental health officer also includes the following stages;
Evacuation stage
- Make observations/carryout inspections to detect and abate nuisance and to prevent the reoccurrence of such nuisance.
Settlement stage
- Give health education to victims.
- Carryout disinfections and disinfectants.
Treatment stage
- Ensure that hospital/medical wastes are sanitarily disposed off.
- Carryout disinfection of materials.
Cleanup stage
- Determine appropriate cleanup method.
- Ensure sanitary disposal of waste generated.
Provision of supplies stage
- Ensure storage and preservation of supplies.
- Ensure fair distribution of supplies.
Conclusion
Quick response to emergency situation saves life and reduces mortality rates of victims. It is important therefore that the Environmental Health Officer understands the emergency situation and identify areas that pertain to him and take appropriate action. In this way, he becomes relevance and contributes his best whenever and wherever the call comes.
Recommendations
Adequate functional drainage system should be constructed to channel rain water to water body and indiscriminate disposal of waste should be discouraged by providing sanitary waste bin at strategic location for the collection of waste.
References
Adeloye, M. and Rustum, P. (2011).Disaster Field Manual forEnvironmental Health Specialist. California: Association of Environmental Health Administrators.
Alexander, D. (2002). Principles of Emergency Planning and Management.Harpended: Terra Publishing.
Bankoff, G. and Hihorst, D. (2003).Mapping Vulnerability: Disaster development and people. London: Queens Press.
European Union (EU) (2012). Natural catastrophe Dominated by U.S. Weather Extreme.Journal on Flood Directives, Article 2.
Sally, W. (2005). Advanced Oxford Learners Dictionary (7thed). London: Oxford University Press.
Wisner, B. and Adams, J. (2002). A Practical Guide on Environmental Health in Emergency and Disaster Management. Wiltshire: Routledge.
World Health Organization (WHO), (2001). Draft Emergency Response plan for Environmental Health. Geneva: WHO.
