1.1 maps. According to Kaoje (2016) flood vulnerability mapping

1.1       INTRODUCTION
AND RESEARCH BACKGROUND

Adeoye;
Ayanlande; and Babatimehin, (2009) Cited in Mmom and Akpi (2014) defined Flood
as an extreme naturally occurring weather event that results in an overflowing of large amounts of
surface water over land that is not
always inundated.  According to Leinster
(2009) flood is an overflow of water that covered the land surfaces that are
normally dry. This includes overflow from water bodies like river, lakes etc.

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Xby CounterflixFloods are considered
to be the worst natural disaster
in the world and are responsible for a third of all natural problems and half of the damages on facilities
around the globe (Mmom and Ayapko, 2014). Alexander;
Viavattene; Faulkner; and Priest (2011) defined flood vulnerability as
“probability of flood occurrences and its potential consequences”. So,
therefore flood vulnerability mapping according to Kaoje and Ishiaku, (2017) is
the presentation or representation of areas that are at risk of flood events on
maps. According to Kaoje (2016) flood vulnerability mapping is very important
for an appropriate urban planning to reduce the likelihood of flood occurrence
and also reduce the consequences of flood disaster when it happen. Flood is the
most common occurring natural disaster that affects humans and their
surrounding environment (Leinster, 2009). This natural disaster is common in
Nigeria, it has been occurring in almost every rainy season (Kaoje and Ishiaku,
2017).

In 2012 about
1.3 million Nigerians were displaced and 431 died from various floods
occurrences and over 30 out of 36 states in Nigeria were affected by the flood
(NEMA, 2012; IRIN, 2012). Flood is no doubt is one of
the major environmental problems affecting the livelihood of an area especially
urban areas, in which Bayelsa State urban areas are not in exemption meaning
that Bayelsa State is a typical flood prone area in the Niger Delta region.
According to Cinque; Crowe; and Davies (2003) cited in Kaoje
and Ishiaku, (2017) it is understood that flood is a hazard that can be avoided
not only by building dams or constructing more flood defence systems but also
by the use of modern technologies and appropriate urban planning that will provide
accurate information on flood prone areas on a map. Geographic Information
System (GIS) is very important in generating such maps through rigorous spatial
analysis (Eludoyin and Weli, n.d).  According
to Burroughs (1987) cited in Eludoyin and Weli, (n.d) GIS can be defined as a
tool for storing, manipulating and displaying large quantities of geographic
information in a computer. They stressed further that the geographic data which
is stored describes objects from the real world in terms of their position on
the earth with respect to known coordinate system. According to Atkinson (2008)
cited in Kaoje and Ishiaku, (2017) GIS application have gained a wide
acceptability. Mapping has becomes the keystone for flood risk management and
communication in representing spatial relationships between hazard and
vulnerability and resulting risk (Alexander et al 2011).

1.2  
PROBLEM STATEMENT

Flood is the most common occurring natural disaster that affects
humans and their surrounding environment (Leinster, 2009). This natural
disaster is common in Nigeria, it has been occurring in almost every raining
season (Kaoje and Ishiaku, 2017). In
Nigeria, urban floods are characteristic of cities located on the Niger delta
region, resulting mainly from poor planning and land use, poor drainage network
and indiscriminate dumping of refuse into drains and streams among others (Isong,
1999).

Xby CounterflixFlooding has been a major environmental problem in Bayelsa State,
Nigeria. It has both environmental and socio-economic effects. It has
endangered human lives and property. Some of such effects include damage to
economic activities and surface water pollution than can lead to water-borne
diseases. In these days of climate change, flooding occur never there is rainfall
in Bayelsa state. In the light of the above statements, flood prone areas need
more attention from the Government and to do that a good management and
accurate information can help to avoid problems of flooding in Bayelsa State.
Therefore, this research will demonstrate how GIS techniques can be use for
flood vulnerability mapping and assessment in Bayelsa state, Nigeria.

1.3   RESEARCH
QUESTIONS

Based on the
above, the following research questions will be raised.

1.    How
GIS technique can be use for flood vulnerability mapping?

2.    What
are the flood vulnerability levels of each Local Government Area of Bayelsa
State?

1.4  
AIM AND OBJECTIVES

The aim of this study is to
assess the flood vulnerability of Bayelsa state in Nigeria with a view of
creating a flood vulnerability map for providing policy maker a framework for
responding to flooding issue.

The
specific objectives are to:

1.    To
create a GIS database for flood vulnerability areas in Bayelsa State; and

2.    To
indentify flood vulnerability levels of each Local Government area of Bayelsa
State.

 

1.5 
 STUDY AREA

1.5.1 Location

Bayelsa
state is located in the heart of the Niger Delta region in south-south part of
Nigeria, between Latitude 4o12’0” N to 5o 24′ 0” N and
Longitude 5o 24′ 0” E to 6o 36′ 0” E. it is one of the
36 state of the federal republic of Nigeria (fig.1)

1.5.2  
Climate

The
climate of Bayelsa state is the equatorial type with rainfall occurring
generally every month of the year (Wizor & Agbabou, 2014). The area is
characterized by high rainfall almost throughout the year with an annual
average of 4180.25. The rainy season mostly occurs between March and November.
The dry season is between December and February. The mean monthly temperature
is between 250 C and 310 C with the hottest
months occurring between December and April. Relative humidity is high throughout
the year but it decreases slightly in the dry season.

 

 

Fig. 1: Bayelsa State, Rivers and Deltas

Source:
Design by Author, 2017

 

 

 

1.6        LITERATURE
REVIEW

 

The
21st century earliest documented climate change and flood research
in Nigeria after a decade was that of Adeoye et al., (2010) in which they
studies flood events in Nigeria and its associated hazards. Their findings
shows that flood had forced thousands of people from their homes while more
than a thousand people lost their lives to flooding at different time and
locations of the federation. Since the works by Adeoye et al., other works on
flooding climate change and flood vulnerability studies were undertaken in the
2010s largely on the issue of flood vulnerability (e.g Dukiya, 2012; mayomi,
dami and maryah, 2013; Mmom and Ayapko, 2014; Anyanmu and udoh, 2016; and kaoje
and Ishiaku, 2017).

Xby CounterflixA
common characteristic of all these studies is their empirical nature. Dukiya,
(2012) use remote sensing and GIS technique to assess the flood vulnerability zones
of the town using the bench mark minimum and maximum water level from the year
1995 to 2005. The study generated land-use / land-cover and flood vulnerability
maps, it was shown clearly that development along the marine road and new
filele mini-dual carriage road are within the floodable area of the river
confluence.

Another
study done by Suleiman et al.,(2014) identify the rick lives and vulnerability
level of the settlement to flood disasters. The results indicated that substantial
part of the settlement falls within the high flood risk zone. Also Mmon and Ayakpo,
(2014) examine flood in Sagbama Local Government Area using GIS to indentify
flood vulnerable areas in Sagbama area of Bayelsa State, Nigeria. The study
recommended that a general flood risk mapping of the entire region for flood
disaster mitigation planning. Flood has been a continuous problem in the Niger
Delta region so the need to update the state of knowledge about flood
vulnerability is need in Niger Delta region.

 

 1.7    MATERIALS AND METHOD

Bayelsa
State is located in the heart of the Niger Delta with a relatively flat terrain
and it has waterways flowing through it and all the water bodies empty their
water in the Atlantic Ocean. The spatial pattern of Bayelsa state makes it
vulnerable to flood hazard. This is what draws the interest of this research
proposal to study the flood vulnerability pattern of Bayelsa state, Nigeria.

1.7.1 Method

These
research will be a quantitative research because of it nature. This is because
the research will study real world phenomena which will use spatial data to
scientifically model the flood vulnerability pattern. Therefore, this research
will adopt GIS techniques to conduct flood inundation mapping and
visualization. The reason why this research want to adopt this method is
because it provide accurate results when conducting flood analyses (National
Academy of Science, 2007)