CAUSES OF EXCESS FLOOD
CAUSES OF EXCESS FLOOD
1.1 Background Of The Study
Flooding is the overflow of water into a normally dry environment, causing flooding and devastation to plants and animals, including humans. Its damage can extend to man-made structures and infrastructures (Udosen, 2011).
Most flood definitions include the damage they produce and vary according to their sources, types, and magnitude. Ating (2003) describes flood caused by rivers as a relatively high flow that overtakes the natural channels given for run-off as well as a high stream that overtops its natural or manmade banks.
Flood is also defined by Wolf (1965) as a high rate of flow in water sources and the inundation of ordinarily dry terrain. According to West (1991), a flood is a body of water that rises to overflow its banks or low-lying areas.
Floods are known to wreak significant harm to people's lives, belongings, and properties all over the world. Flooding is responsible for one-third of all natural catastrophe deaths, injuries, and damage (Askew, 1999; Etuonovbe, 2011).
People, buildings, infrastructure, agriculture, and open recreational spaces are common “receptors” to this damage. Flooding also has enormous social and emotional costs, which are typically broad and indiscriminate in flooded communities.
They include being displaced from one's home, losing personal goods, and feeling fearful and insecure as a result of such an incident. Flooding can have a ripple effect on the economy, causing firms to lose customers, inventory, data, and production. Tourism, farming, and cattle are all potentially affected.
Flooding can render utilities and transportation infrastructure inoperable. Portable water supplies may get contaminated during a flood, causing immediate health impacts in humans and animals. Other critical infrastructures may potentially be affected, as was the case in Britain during the summer floods of 2007 (RIBA, 2009).
Even in a sophisticated country like the United Kingdom, the Association of British Insurers estimates that the cost of the July 2007 flooding in insurance claims alone was more than three billion pounds (RIBA, 2011). The flooding pattern is consistent throughout the world.
Flooding in Nigeria, for example, has displaced millions of people, wrecked businesses, polluted water sources, and increased the risk of disease transmission (Baiye, 1988, Akinyemi, 1990, Nwaubani, 1991, and Edward- Adebiyi, 1997).
a) Flooding sources Tidal flooding, fluvial flooding, ground water, pluvial flooding, flooding from sewers, and flooding from man-made infrastructure are the six recognised sources of flooding. Ø Flooding caused by tidal action A combination of low pressure weather systems and high tides might overwhelm sea and river defences.
The cycle of the tides where drainage is accessible limits its duration. Fluvial flooding occurs when the capacity of a river is surpassed by rainfall or snow, resulting in a rising water level that can overflow onto floodplains along the river.
Ground Water – As ground water levels rise, low-lying areas adjacent to aquifers may flood. This flood is mostly seasonal and slow. Pluvial Flood -Refers to surface water from rainwater run-off, primarily from urban or rural terrain with low absorbency.
As development increases in urban areas, land surfaces grow in their regions of non-permeable surfaces, combining into severe rainfall, resulting in localised flooding. Flooding from sewers occurs when there are malfunctioning sewers or when sewage capacity is routinely surpassed due to excessive surface water runoff in a short period of time.
Man-made infrastructure flooding occurs when man-made structures such as canals and reservoirs fail, flooding communities downstream (RIBA 1999).
1.2 Statement Of The Problem
Although floods can occur at any time of year, there are some seasonal trends for flooding in Uyo Local Government Area based on the various natural processes that create floods.
Rainy Season floods are caused by high rainfall on wet ground, which penetrates into previously dry lands and causes extensive damage to people and property.
1.3 Objectives Of The Study
The primary goal of this research was to identify the immediate and remote causes of regular floods in Uyo. It specifically seeks to;
1. Identify the primary causes that may be more responsible for the current flooding in Uyo City.
1.4 Research questions
1. What are the causes of the city of Uyo's regular flooding?
1.5 Research Hypothesis
Ho: Uyo city does not experience frequent flooding.
Hi: The city of Uyo is frequently flooded.
1.6Significance Of The Research
This research will assist in determining the reasons of the recent flooding in Uyo City. A number of physical flood characteristics were considered in order to accomplish this successfully. These key physical features are as follows:
a) Water depth
c) Inundation duration
c) Inundation zone
d) Flow velocity
e) Relationships between frequency and recurrence
f) Flood time (also known as flood time lapse or flood-to-peak interval).
h) Maximum flood
i) The discharge rate rises and falls.
i) The sediment load and
k) Total volume of flood run-off.
1.7 The Study's Scope
The research looks into the causes of excessive flooding in Uyo Local Government Area, Akwa Ibom State, Nigeria. Because of the constant flood occurrences in Uyo during rainy seasons and her representative nature to other flood prone locations, Uyo Local Government Area is utilised as the case study for this research.
1.8 Limitations Of The Study
The study area is Uyo metropolis. This city is located in the Uyo Local Government Area. It is densely populated, with nearly all of Uyo falling within the Capital City Development Area (UCCDA).
However, the study has some shortcomings, most notably in the area of data gathering. Other considerations that would limit the scope of the investigation include financial constraints and the amount of time available to complete the study.
1.Definition Of Terms
Flood: A vast amount of water flowing beyond its customary bounds, particularly across typically dry ground.
Uyo LGA: Akwa Ibom State's capital in Nigeria.