Floods are naturally occurring phenomena that are part of the physical and biological process which have shaped our nation’s landscape. It occurs in Nigeria environment when there is heavy rain fall for prolonged period of time. The data collection for this research was by use of primary and secondary information; questionnaire was administered by face to face interviews and key informant surveys. Analytical technique was the univariate statistical methods. The results revealed that there is clear evidence of damages to properties and that there are hazards and risks faced by these households as shown in Tables 1-4 respectively. Table 3 specifically shows the financial losses incurred annually by residents to the tune 5 million naira and above. However, the continued hazards and risks as a result of flood incidence have affected their overall income which hitherto is found within (N20000.00 - N25000.00) about 22.8% of the respondents fall in this income bracket. Furthermore, the research also revealed that about 30% say the flood has affected their income, while 29.4% say their buildings are affected. Also about 37.8% of respondents say that the flood incidence occurs all through the rainy season. The research recommends an aggressive review of the Port Harcourt Master Plan and the implementation of the development control tools in the 1992 Urban and Regional Planning Law.
Floods are repeatedly in the head lines of local, national and the international media. Most of the stories concern comparatively minor events which cause little damage and are soon forgotten except by those most directly affected. Some, however, concern major disasters involving loss of life and the destruction of property. Not surprisingly, therefore, floods are the cause of most natural disasters affecting society. In a study of major natural hazards (excluding drought) on the world scale over a 20-year period, from 1947 to 1967, [
A flood is a body of water which rises to overflow land, which is not normally submerged [
Most urban flood disasters are manmade. Floods are natural phenomena, but man has put himself at risk by developing flood plains for settlements, agriculture, industry, and building roads, bridges and railways lines in floodable positions. Channels to drain the excess water during precipitation are in many cases not provided especially in less developed countries or are inadequate, but even when they are available, the flood problem in some cases persists [
In Port Harcourt Metropolis, as in other cities in Nigeria and the rest of the world, the flood situation is worsening. The situation is exacerbated by both natural and human factors. The natural factors are prolonged rainfalls, poor management of flood plains and wet lands. Human factors are urbanization, failure in engineering flood control structures, devastation of flood plains and wet lands by man. The effects of floods on the environment and man are devastating. On man, many lives are lost properties destroyed, crops worth millions of naira have always been lost and more over on the environment, its aesthetic values is tampered with as soil is washed away.
According to [
It is in the light of the huge human and material losses accompanying floods in Port Harcourt Metropolis that this study was motivated.
These are as follows:
1) The study will identify the possible hazards and risks faced by residents of Port Harcourt Metropolis as result of flooding;
2) The study will highlight the socio-economic impacts of flood on residents of Port Harcourt Metropolis.
Port Harcourt was subdivided into four sub basin areas using [
The sub-basins are:
1) The area bounded by Bonny and Diobu Creek (SB I);
2) The area bounded by Diobu creek and Amadi Creek (SB II);
3) The area bounded by Amadi creek and Okpoka River (SB III);
4) The area on the northeast of the Okpoka River (SB IV).
Within these sub basins, the street map of Port Harcourt was super imposed on the SPDC map to select streets for the sample. Using the stratified random sampling technique, two streets each were chosen, from which hou- ses were systematically chosen for questionnaire administration.
Data was collected from secondary and primary sources. Secondary sources included published and unpublished information such as [
The study applied a variety of analytical techniques, especially univariate statistics (means, medians, modes, percentages, ratios and rates). The following formulae [
Group Mean
where fi = number of cases in the ith category;
mi = mid-point of ith category;
k = number of categories;
N = number of cases;
X = mean.
Standard Deviation
where fi = number of cases in the ith interval;
k = number of intervals;
Xi = mid-point of class;
N = number of cases;
S = standard deviation.
The frequency of flooding in the sampled area as shown in
The hazards and risks of floods on the socio-economic lives of the residents of Port Harcourt Metropolis are as follows and shown in
• Loss of lives;
• Loss of property;
• Pollution of streets and houses;
• Pollution of source of water supply;
• Displacement of household members;
• Over flowing of soakaways, etc or septic tanks;
Flood Impact | SB I | SB II | SB III | SB IV | Row Total | |||||
---|---|---|---|---|---|---|---|---|---|---|
N | % | N | % | N | % | N | % | N | % | |
Loss of income | 33 | 41.25 | 25 | 31.5 | 20 | 25.0 | 18 | 22.5 | 96 | 30.0 |
Damage to building (tilting/crack walls) | 18 | 22.5 | 20 | 25.0 | 25 | 31.25 | 31 | 38.5 | 94 | 29.4 |
Loss of property and health impact | 14 | 17.5 | 22 | 27.5 | 21 | 26.25 | 14 | 17.5 | 71 | 22.2 |
Disruption of economic/social activity | 10 | 12.5 | 13 | 16.25 | 14 | 17.5 | 10 | 12.5 | 42 | 13.1 |
Indifferent | 5 | 6.25 | - | - | - | - | 7 | 8.75 | 12 | 3.75 |
Total | 80 | 100 | 80 | 100 | 80 | 100 | 80 | 100 | 320 | 100 |
Frequency of Flood | SB 1 | SB II | SB III | SB IV | Row Total | |||||
---|---|---|---|---|---|---|---|---|---|---|
N | % | N | % | N | % | N | % | N | % | |
1 - 3 times | 5 | 6.25 | - | - | 8 | 10.0 | - | - | 13 | 4.0 |
4 - 6 times | 12 | 15.0 | 13 | 16.25 | 10 | 12.5 | 15 | 18.75 | 50 | 15.6 |
7 - 9 times | 14 | 17.5 | 20 | 25.0 | 12 | 15.0 | 16 | 20.0 | 62 | 19.4 |
10 times plus | 18 | 22.5 | 22 | 27.5 | 14 | 17.5 | 20 | 25.0 | 74 | 23.0 |
All through the Rainy season | 31 | 38.5 | 25 | 31.25 | 36 | 45.0 | 29 | 36.25 | 121 | 37.8 |
Total | 80 | 100 | 80 | 100 | 80 | 100 | 80 | 100 | 320 | 100 |
Value of Flood Loss in Naira | Total Respondents | % |
---|---|---|
Fifty thousand naira | - | - |
Fifty one thousand naira - Two hundred thousand naira | - | - |
Two hundred and one thousand naira - Three hundred thousand naira | 2 | 0.63 |
Three hundred and one thousand naira - Four hundred thousand naira | 3 | 0.93 |
Four hundred and one thousand naira - Five hundred thousand naira | 5 | 1.6 |
Five hundred and one thousand naira - One million naira | 10 | 3.1 |
N1 m - N2 m | 50 | 15.6 |
N2 m - N3 m | 70 | 21.9 |
N3 m - N4 m | 80 | 25.0 |
N5 million and above | 100 | 31.1 |
Total | 320 | 100 |
Authors Research Finding (2012).
• Outbreak of epidemic;
• Incidence of diseases;
• Collapse of buildings;
• Cracking of walls/tilting of foundations of buildings;
• Poor waste disposal/litter of waste on streets on typical rainy day;
• Unsightly nature of the Metropolis especially after rain fall, etc.
According to [
S/N | Sensitivity | Hazard | Impact | Qualification | Likelihood | Consequence | Impact Rating |
---|---|---|---|---|---|---|---|
1 | Flooding in the area last for 2 - 7 days, during rainy season. | Damage to buildings, properties, health impact from overflow soakaways, etc, obstruction of traffic, etc. | Loss of property, disease epidemic, death, traffic congestion, etc. | • Positive • Direct • Short term • Reversible • Local • Incremental | High | High | Significant |
2 | The frequency of flooding in the area is all through the rainy season. | Poor crop yield, loss of income, damage to buildings/properties, health impact resulting from disease epidemic, low infrastructure development, etc. | Poor yield of crops, collapse of buildings, loss of properties, disease epidemic. | • Positive • Direct • Long-term • Reversible • Local • Non-incremental | High | High | Significant |
3 | The type of flood in the area is usually urban flood. | Flash flood/flood pond age, temporary obstruction of activities, unsightly scenery, i.e. overflowing of drains/wastes. | Loss of property, loss of income, and loss in aesthetic value of the city. | • Positive • Direct • Short term • Reversible • Local • Incremental | Moderate | Little | Minor |
4 | The greatest impact of flooding in the area is on income of residents. | Frequent replacement of household items, possible relocation, collapse/cracks of buildings, health effect by constant treatment in hospitals, etc. | Loss of income. | • Positive • Direct • Temporary • Reversible • Local • Non-incremental | High | Great | Major |
5 | Does the flood affects buildings, etc. | There are evidences of cracked walls and possible collapse of building because of frequent flooding of the area. | Cracks on walls of buildings/collapse of buildings. | • Positive • Indirect • Temporary • Local • Incremental | Medium | Moderate | Significant |
Furthermore, an environmental condition of interest was measured, that is the type of buildings found in the neighbourhood. It was also a parameter used to assess the impact of flooding in the area. From the investigations,
The extent and intensity of damage a flood event can cause is dependent on the duration, depth and velocity of the action [
Age Yrs. | N | % | Education | N | % | Occupation | N | % | Monthly Income | N | % |
---|---|---|---|---|---|---|---|---|---|---|---|
<20 | 41 | 12.8 | Non formal | 53 | 16.6 | Unemployed | 64 | 20.0 | Less than N20,000 | 45 | 14.1 |
21 - 25 | 63 | 19.6 | Primary | 52 | 16.2 | Civil servant | 48 | 15.0 | N20,000 - N25,000 | 73 | 22.8 |
26 - 30 | 57 | 17.8 | Secondary | 56 | 17.5 | Self employed | 48 | 15.0 | N25,001 - N50,000 | 63 | 19.7 |
31 - 35 | 75 | 23.4 | Post secondary | 71 | 22.2 | Artisans | 102 | 31.1 | N50,001 - N100,000 | 56 | 17.5 |
36 - 40 | 58 | 18.1 | Others (craft) | 88 | 27.5 | Professionals | 58 | 18.1 | N100,001 - N150,000 | 53 | 16.6 |
Above 40 | 26 | 8.1 | - | - | - | others | - | - | Above N150,000 | 30 | 9.4 |
Total | 320 | 100 | 320 | 100 | 320 | 100 | 320 | 100 |
House Type | SB I | SB II | SB III | SB IV | Row Total | |||||
---|---|---|---|---|---|---|---|---|---|---|
N | % | N | % | N | % | N | % | N | % | |
Storey building | 21 | 26.25 | 22 | 27.5 | 20 | 25,0 | 25 | 31.25 | 88 | 27.5 |
Bungalow | 18 | 22.5 | 15 | 18.75 | 14 | 17.5 | 20 | 25.0 | 67 | 20.0 |
Block of flats | 20 | 25.0 | 22 | 27.5 | 25 | 31.25 | 22 | 27.5 | 89 | 27.8 |
Rooming houses | 15 | 18.75 | 18 | 22.5 | 21 | 26.25 | 13 | 16.25 | 67 | 20.0 |
Others specify | 6 | 7.5 | 3 | 3.75 | - | - | - | - | 9 | 2.8 |
Total | 80 | 100 | 80 | 100 | 80 | 100 | 80 | 100 | 320 | 100 |
as a result of the flooding, while 29.4% of the people say that the incident had caused damage to their building in form of cracked walls and tilting of the structure. This is indeed a high risk case if nothing is done to ameliorate the situation. On the conditions of the environment in terms of houses, the survey revealed that about 27.8% were block of flats and 27.5% of storey buildings were affected throughout the period of the flooding.
The ugly situation has affected the people adversely as social/economic activities are disrupted by the flood incidence, 13.1% attested to this and 22.2% says the flood has caused them the loss of property/health challenges (
Flooding has been one of the most costly disasters in terms of monetary value, property damage and human casualties [
Flooding in the metropolis has put lives at risk as identified in the social impact analysis in this paper; also most residents have incurred huge losses in terms of income and property damages resulting from flooding.
The continued flooding of the city as revealed in this paper contains three folds: firstly, the attitude of developers who build on natural drainage line; secondly, the non review of the master plan of the city and the non performance of the relevant agencies of government charged with the control of development. The research recommends an aggressive design of a drainage plan to be incorporated in the reviewed master plan of the city. The paper also suggests that government should assist the flood victims with some soft loans to ameliorate their plight annually. Finally, there should be strict penalty for every development on flood plains.