Geospatial Mapping and Analysis of the 2012 Flood Disaster in Central Parts of Nigeria

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8
th

National GIS Symposium. Dammam. Saudi Arabia. April 15
-
17, 2013


1


Geospatial Mapping and Analysis of

the

2012 Flood Disaster in

Central
Parts of
Nigeria


*Ojigi, M. L., **Abdulkadir, F. I. and *Aderoju, M.
O
.

*
National Space Research and Development Agency (NASRDA),

Pyakasa Junction, Umaru Musa Yar’Adua Way, Abuja, Nige
ria

E
-
mail:
lazarus.ojigi@nasrda.gov.ng
,
lmojigi@yahoo.com
;

laideaderoju@gmail.com


Phone
: +234
-
8166930684

**Department of S
urveying and Geoinformatics,

Abubakar Tafawa Balewa University (ATBU),

Bauchi, Bauchi State, Nigeria.

E
-

mail:
isahafuntua@yahoo.com

Phone
:

+234

803

586

2081


Abstract


The flood events of August
-
October 2012 in
Nigeria have pushed rivers over their
banks and submerged hundreds of kilometers of urban and rural lands. Flash floods
are common features in Nigeria during the rainy season (May
-
October), but the 2012
floods have been described as the worst in over 40 ye
ars. This study therefore aims
at the geospatial mapping and analysis of the 2012 flood disaster in parts of Central
Nigeria (Niger
-
Benue
-
Kogi) as a tool for contingency planning and emergency
management. Satellite imageries [MODIS of 20
th

October, 2008
(p
rior)
and 13
th

October 2012
(during)

provided by NASA; NigeriaSat
-
1 of 2007, and Quickbird of
2006], Base Maps, SRTM DEM, GPS Coordinates, and flood photographs acquired
during field works were integrated to map the flood plain, and analyse the spatial
ext
ent and disaster risk areas. A comparison of the

prior

and
during

i
mages of the
flooded areas showed that, in 2012, both Rivers Niger and Benue burst their banks,
engulfing the small lakes, ponds, farmlands and settlements within the flood plain.
The estim
ate of the Internally Displaced Persons (IDP) by the flood disasters in the
study area was about 5
66

thousand, while crops were ravaged and transportation
routes severed in the affected communities. The study showed that, the natural
boundary of the flood
plain was not exceeded during the flooding, but due to strong
affinity to the flood plain by the communities in a claimed reverence to their ancestral
heritage of economic survival, there was huge avoidable socio
-
economic loss to the
floods.


Key words: Sa
tellite Data, Geospatial Mapping, Analysis, Flood Disasters and
Risk
,
Vulnerability
, IDPs



1.0

INTRODUCTION


Flooding

is one of the most frequent and widespread of all environmental hazards
and
of various types and magnitudes. It
occurs in most terrestrial po
rtions of the
globe, causing huge annual losses in terms of damage and disruption to economic
livelihoods, businesses, infrastructure, services and public health (Ikhuria, et al
2012). Long term data on natural disasters suggest that floods and wind storms

have
been by far the most common causes of natural disaster worldwide over the past
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National GIS Symposium. Dammam. Saudi Arabia. April 15
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17, 2013


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100 years (Few
et al
. 2004).

Flood hazards are natural phenomena, but
the
damage
s

and losses from floods are the consequence of human action.

It has known
that
floods

can
be caused by anthropogenic activities and human interventions in the
natural processes such as increase in settlement areas, population growth and
economic assets over low lying plains prone to flooding leading to alterations in the
natural drainage and ri
ver basin patterns, deforestation and climate change
(European Commission, 2007; Balabanova and Vassilev, 2010; Kwak and Kondoh,
2008).

Urbanization

aggravates flooding by restricting where flood waters can go
. In an
urban area
, large parts of the ground
are covered
with roofs,
tarred roads and
pavements.
These

obstruct

sections of natural channels and
buil
ds

drains that
ensure

water movement

to rivers faster than it
could

under
the
natural conditions.

Another factor in an urban setting is the population d
ensity.

As more people crowd
into cities, so the
floods
effects intensify.
Consequently
even quite moderate storm

could
produce high flows in rivers because there are more hard surfaces and drains
(
ActionAid International, 2006
).
In extreme cases urban flo
ods c
an result in disasters
that set
back urban development by years or even decades. Given the high spatial
concentration of people and values in cities, even small scale floods may lead to
considerable damages. Recent statistics clearly indicate that econ
omic damages
caused by urban floods are rising (MunichRe, 2005).

In tropical regions, flooding of high magnitude that have resulted in serious
consequences have b
een caused by heavy rain
storms, hurricanes, snow melt and
dam failures (Jeyaseelan, 1999; Jeb
and Aggarwal, 2008).
However t
he obvious
reason for flooding especially in municipalities and coastal areas in Nigeria lies in the
wide distribution of low
-
lying coastal areas and river floodplains, and because these
areas have fast become a long standing
attraction for human settlement
(Ologunorisa and Abawua, 2005).
This subsistence attraction has become a high
flood risk factor in most of Nigerian flood plain regions.



Figure 1
.1
: Flood risk and its reduction Model
[adapt
ed from
Associated Programme
on Flood Management (
APFM)
, 2006]


Crichton

(1999) described risk as ‘the probability of a loss and this depends on three
elements:
hazard, vulnerability, and exposure
. If any of thes
e three elements
increases or decreases, then the risk increases or decreases respectively’. Flood
risk is therefore, a product of
flood hazard, exposure

and
vulnerability.

While
exposure to floods refers to whether people or assets are physically in the p
ath of
flood waters or not, vulnerability may be described as
“the conditions determined by
physical, social, economic and environmental factors or processes, which increase
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National GIS Symposium. Dammam. Saudi Arabia. April 15
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3


the susceptibility of a community to the impact of hazards.”

(UN/ISDR, 2004;

UNDP,

2004
)
.
The ability to measure vulnerability is increasingly being seen as a key step
towards effective risk reduction and the promotion of a culture of disaster resilience
(Birkmann, 2006).


Two major flood events took place between the months of Septemb
er and October
2012 in Nigeria, namely, the Ladgo Dam Flood and Niger
-
Benue Flood (Lokoja and
Rivers Benue
-
Niger adjoining States). The release of waters from Ladgo dam in
Cameroon into the River Benue flood plain, coupled with the effect of global warming

were largely responsible for the 2012 flooding in Nigeria.
These events pushed most
of the country’s rivers over their banks and submerged hundreds of kilometers of
urban and rural lands.

The
significance of the year
2012 flood disasters in Nigeria
lies
in the fact that they
were unprecedented in the past forty years.
M
ost
p
arts of
the
central states of
Nigeria and other adjoining states
along the

rivers Niger and Benue were devastated
by the
se

floods, causing huge destruction to the rural and urban infra
structures
(farmlands/crops, roads, buildings, drainages, bridges, powerlines, etc) and socio
-
economic lives of the areas


There are a number of tested techniques that could be used singly or in combination
to map flood hazards

and risk
; which include info
rmation on historical floods, soil
maps, aerial photographs, hydrological modeling of the major rivers, use of national
digital terrain model and water levels, and satellite imagery, etc
(Hassan et al, 2000;
Bruzzone and Smits, 2002;
Kondolf and Pigay
,
200
3;
Mansor et al, 2004
; Onana et
al (n.d)
; Ojigi, 2010
).

Geospatial technologies have been
effectively

used
globally
in
respects of flood and
water logging

di
saster monitoring and evaluation
, water
resources and

water environment investigation
, soil corrosi
on and soil protection,
river and reservoir sedimentation monitoring, river/lake and rive
r mouth evolvement
investigation

as well as soil moisture and drought condition monitoring (Li and
Huang, 2002).

Ojigi and Shaba (2012) identified t
he integration of s
ynthetic aperture
radar data and digital terrain model as a rapid flood hazard
s

and risk mapping
technique for emergency management, as it offers in
-
situ inundated status and
terrain factor for rescue and relief operations

.
A combination of techniques were

exploited in this study.



1.1

Statement of Problem


Flash floods are common features in Nigeria during the rainy season (May
-
October),
but the country’s flood events of the year 2012 have been described as the worst in
over 40 years.
Two major flood events
took place between the months of September
and October 2012 in Nigeria, namely, the Ladgo Dam Flood in Adamawa State, and
the
Rivers Benue

and
Niger adjoining States Flood
s

(Niger state

and Benue

state
).
These events have pushed most of the country’s river
s over their banks and
submerged hundreds of kilometers of urban and rural lands.
The Niger
-
Benue
valley

which bear
s

the two major rivers (Niger and Benue) in Nigeria

lies in relatively low
-
lying areas and
on the
river
s

floodplains
.

Because
of the
ir

huge a
gricultural and
natural resources potentials, these areas have become a long standing attraction
areas
for human settlement
s

and subsistence activities in the central part of Nigeria.

The 2012 flood events brought untold hardship on the residents of
the
se

areas
hence a comprehensive geospatial mapping and analysis for emergency
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National GIS Symposium. Dammam. Saudi Arabia. April 15
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4


management and flood contingency planning in the
region

is
require
. This study
therefore aims at the
g
eospatial
m
apping and
a
nalysis of the 2012
f
lood
d
isaster in
parts of the c
entr
al
states

of Nigeria
and
environs for the effective management of
the menace.



1.2
Objectives


The objectives of the study are to:

i.

Delineate and map the actual flood extent during the 2012 flood disasters in
Nigeria using satellite imageries and field val
idation techniques;

ii.

Map the vulnerable area
s

using Digital Elevation Model, Settlement maps and
satellite imageries;

iii.

Determine the flood disaster impacts (physical and economic) on the life and
property of the residents of the affected areas;

iv.

Investigate

a
ny socio
-
cultural risk factors that exacerbate the general loss
during the flood disaster;

v.

Carry out the spatial analysis of the flood plain and
suggest strategies for
future flo
od disaster and
risk mitigation in the study area.


1.2

Study Area


The
under cons
ideration in this study
have a total land mass of
194429.7sqkm

which

compris
es

of

five States in

the central part of

Nigeria
.

The

States
include
;

Benue

(
30732.69sqkm
)
, Kogi

(
29044.79sqkm
)
, Niger

(
72200.9sqkm
)
,
Nasarawa

(
26385.04
)

and Kwara States

(
36066.31
sqkm
)

respectively.
Two
other

of
states
in the region

(Plateau and Taraba states) were however not considered in this study.

The
central

region of Nigeria is described as the food basket of Nigeria due to its favourable
climatic conditions for agricultura
l activities.

The Benue and Niger Rivers converge in
Lokoja

town

and from there the Niger flows south toward the sea

(Figure 1.2).




Figure
1.2
:
The Study Area







8
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National GIS Symposium. Dammam. Saudi Arabia. April 15
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5


2.0
MATERIALS AND METHODS

2.1
Dataset
s

Used

Space based techniques were
used

in the floo
d extent and vulnerable area mapping
.
The datasets include

high resolution

(3m)

SAR
imageries (RADAR
SAT

and Infoterra
SAR
)
, SPOT
-
5

and NigeriaSat
-
1 imageries. The

RADAR
SAT
,
Infoterra SAR, and
SPOT
-
5

data
were provided courtesy of the
United Nation platform

for Space
-
based
Information for Disaster Management and Emergency Response (
UN
-
SPIDER
)
, of
which
the National Space Research and development Agency (
NASRDA
)

is the
Charter representative in Nigeria.


Other base data from the Integrated Mission for Sustai
nable Development (IMSD)
Project for
Nigeria,
which includes

the USGS Shuttle Radar Topography Mission
DEM (SRTM), the National river/water body map, settlement/road map, etc were
integrated with the satellite imageries to effectively delineate the vulner
a
ble area
s

to
flooding

as observed

during the 2012 flood disaster in Nigeria.
The other datasets
used include
October 13, 2012, and October 20, 2008 images of the Niger and
Benue Rivers captured by
Moderate Resolution Imaging Spectroradiometer

(MODIS)
on NA
SA’s
Terra

satellite
.

The
MODIS images comprised of
visible and infrared
channels

to better distinguish
between water and land. Water ranges in c
olor from electric blue to navy, and lighter

shades of blue can indicate sh
allower depths or heavier loads of sediment.
On the
other hand, v
egetation is bright green, and clouds appear in shades of pale blue
-
green.

The MODIS images were provided

courtesy of
Lance

MODIS Rapid
Respons
e Team

at NASA GSFC.


2.2
Field W
ork

and Primary Data Collection


As a preparation
for the field work, a rapid map, which is made up of terrain and
relief maps integrated with settlement and road maps were prepared for the flood
disaster areas in order to

guide the field team.



The field work was

conducted to validate the flood extent as captured by the satellite
imageries and to identify other inundated areas by the flood. Trimble GPS receivers,
Sony

Nex
-
3

D
igital C
amera
s
,

printed copies of satellite ima
geries
,

and base maps
were used as the field tools to delineate the inundated areas. The means of transport
used include boats and vehicles, which were alternated as the field situation
requires.
The GPS coordinates and photographs of affected communities
were
acquired and plotted on the rapid maps
d
eveloped for the emergency management
and evacuation of internally displaced persons (IDPs).
A survey of the affected
communities in the flood disaster was carried during the field work and basic data on
the imp
acts (number deaths, farmland/agricultural lands lost, number of displaced
persons, etc) on the life and property of the people were collected.


2.3
Data Processing Techniques


The data processing techniques adopted include, data evaluation,
georeferencin
g
and mosaicking,
data sub
-
setting
, feature extraction,
terrain modeling
,

river/water
body and settlement/road map
s

update
from satellites images and
integration.

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National GIS Symposium. Dammam. Saudi Arabia. April 15
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2.4
Vulnerable Area
to

Flood
Disaster

and Risk
Mapping


A combination of the RADARSAT, Infote
rra SAR, SPOT
-
5 imageries, Shuttle Radar
Topography Mission (SRTM) DTM,
and the
coordinates of spatial locations of flood
water were used to establish flood extent
for both Ladgo Dam flood and the Niger
-
Benue River flooding,
and
the final
flood plain mappi
ng of the
central part of Nigeria
.

The settlement
map of Nigeria produced by the National Space Research and
Development Agency (NASRDA) in 2008 was

used to
co
-
locate

flooded areas with
settlement
s.

GPS coordinates and field photographs of the flooded regi
ons of the
study area

were added to the inundated area database
. The study area was
thereafter categorized into,
highly vulnerable
,
moderately vulnerable
, and
non
-
vulnerable

to river flood

disaster and risk
, using ground elevation, geology, flood
history a
nd nearness

(buffer)

to river channel as criteria.

Flood risk map was
produced using the exposure of the vulnerable area to flood hazards.


2.5
Spatial

Analysis Techniques


Spatial Analysis of the inundated
area carried out include query of number
of
comm
unities affected and their proximity to the river channel, classification of terrain
elevation into three categories of 0
-
100m, 101
-
200m and 201
-
above

to represent the
highly, moderately and non
-
vulnerable regions for the study area. Buffer analyses of
100
0m, 2000m

and 3000m

were carried to validate the proximity factor in the flood
disaster and risk vulnerability classes based on the
physical, social, economic and
environmental factors or processes
of the study area
.


3.0
RESULTS AND DISCUSSION


3.1
Result
s


The major results of the study include the

production of the

2012 flood extent Map,
vu
lnerable area and floodplain maps,
Flood disaster impacts
figures
,
identification of
the
Socio
-
cultural risk factors and attitudes that exacerbate the general loss dur
ing
the flood disaster. Other
s

include

the spatial analysis (Query and Buffering)

results

of
the flood risk zones and the

Identification of s
ome

possible

strategies

options

for
future flood disaster and risk mitigation in the study area



8
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National GIS Symposium. Dammam. Saudi Arabia. April 15
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7



Figur
e
3.1(a)
:
Map of Settlement and Rivers/Water bodies prior the flood (July,
2008)
;

(b)

Map of Settlement and Rivers/Water bodies during the flood (Oct
ober
, 2012)




Figure 3.2
a
:
Flood Vulnerability Map of
Parts of
Central

States

of Nigeria



Figure 3.2b:
Relief a
nd
Flood Plain

Map of Parts of Central States of Nigeria



8
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National GIS Symposium. Dammam. Saudi Arabia. April 15
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Table 3.1:
Estimated
of the physical impacts
of 2012 Flood disasters in
Parts of the
Central State
s

of Nigeria


State

No of Internally
Displaced Persons
(IDPs)

Total Inundated
Area

(sq.km)

Kogi

31
2,823

2596.036

Niger

80,545

668.4205

Benue

112,362

932.46

Nasarawa

29,431

244.2393

Kwara

31,306

259.7999

Total

566,466

4700.956




Figure 3.3:
An Aerial View of 2012 flood in Parts of Lokoja, Kogi State, Nigeria


(22
nd

October, 2012)


Fig

3.4
: Comm
unities and Towns Affected by the 2012 flood in Parts of the Central
States in Nigeria

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National GIS Symposium. Dammam. Saudi Arabia. April 15
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Fig

3.5
: Flood Risk Map of the Central Parts of Nigeria


3.2
Discussion

of Results


Figures 3.1a and b shows the comparison of the spatial coverage prior and during
f
lood

disasters in the study

area
. The actual area affected by the flood was an
excess of about 4701sq.km beyond the natural limits of the Rivers Niger and Benue,
thereby inundating about 164 communities within the buffer and low
-
lying zones of
the rivers.


F
ig
ure

3.2

shows

areas vulnerable

to flood hazard and
risk

in parts of the Central
States of Nigeria
. The
vulnerability was

classified
into

three categories, namely
highly vulnerable
,
moderately vulnerable,

and
non
-
vulnerable

to river flood
disaster and r
isk, using ground elevation, geology, flood history and nearness
(buffer) to river channel as criteria
. The
areas

on terrain

elevations
0
-
100m
were

categorized

as highly vulnerable areas,
while those on
terrain

elevations
of
101
-
201m

and 201m
-
above were

ca
tegorized

as moderately vulnerable and
non
-
vulnerable

areas respectively
.

Thus
locations of ground elevations

120m above mean sea level (AMSL) were
considered as safe ground for evacuation and establishments of emergency relief
camps during the 2012 floo
d events
. This was

b
ased on the
field

assessment
,
terrain

analysis
,

the flood water heights of 12.5
-
15m above natural river level,

and
socio
-
economic and environmental processes in the study area,
.


Though, the
selected
lower limit
terrain elevation

of 120
m

fall
s

within the regions of
moderate vulnerability, but
there was

no
record of such locations

being
inundated

in
the 2012 flood events;

rather the flood water
s

were confined to areas of high
vulnerability
.
From

the F
igure 3.2b,
which shows the relief and

f
lood
p
lain

map of
parts of central states of Nigeria
it is clear that the flood water did not exceed the
natural flood plain of the study area.


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Figure

3.3
show
s

an aerial view of the flood disaster in
a part

of Lokoja, Kogi State,
Nigeria
(22
nd

October
, 2012)
.

Table 3.1 is summary estimate of the physical impacts
of 2012 Flood disasters in
the study area
.

However, t
he study

could not ascertain the
number
of
deaths
caused by
the flood disasters in the study area due to socio
-
political sentiments attached

to it.

Total estimates of 566,466 persons were

displaced
in the Kogi, Niger, Benue, Nasarawa and Kwara States
by the flood disaster
.

Kogi
State accounted

for
the highest IDPs of
about 55.2%
,

while

Niger
, Benue, Nasarawa
and Kwara States

accounted

for abou
t
14.2%, 19.8%, 5.2%, and 5.5% respectively
.




Figure 3.6:
IDPs Chart from the
2012 Flood
in Parts of Central State of Nigeria.


Fig 3.4

show the
164
communities

inundated by the flood

in the study area. From the
spatial analysis
all the

affected
164 com
munities
were

located in the
natural
flood
plains of
rivers Niger and Benue
.

Apart from the excessive rainfall experienced in
2012, a
nthropogenic factors such as unapproved land uses, uncontrolled buildings
and infrastructures at the river banks and spill
ways were major contributors to the
flood disasters in the study area.

The potential implication
s

of the impact of the flood
in the study area and environs
are

health
hazards, food shortage and infrastructure
failures.



Figure 3.5 shows the flood risk map

of the Central Parts of Nigeria, and from the
buffer analysis, all areas within 3000m buffer being in the flood plain, and immediate
catchment of natural river courses are at very high risk of flood disaster damage. The
places within the buffer zones of 1
000m
-
3000m, except in major towns have no
relevant infrastructure for emergency operations; hence are largely at risk of total
loss of agricultural lands/crops, IDPs and even loss of life.



Socio
-
cultural risk factors such as
poor
infrastructure for evac
uation and relief
(roads, waterways, drainages, health facilities, etc
), cultural belief, religion, and
superstition exacerbated the general loss during the flood disaster. A major cultural
factor is the strong affinity to the flood plain and reverence to

ancestral heritages of
most affected communities. Despite the predictions of unusual rainfall in 2012 by the
Nigeria Meteorological Agency (NIMET), and the early warnings by the National
Emergency Management Agency (
N
EMA) most affected communities relied
on
history of non
-
flood disasters in their life times and the cultural belief that, the flood
plain is their ancestral heritage; wh
ich if abandoned will displease

their ancestors.
Also, t
he Niger
-
Benue valley bears the two major rivers (Niger and Benue) in

Nigeria
which lie in relatively low
-
lying areas and river floodplains, and endowed with huge
agricultural and natural resources potentials. As a result, these areas have become a
8
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National GIS Symposium. Dammam. Saudi Arabia. April 15
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17, 2013


11


strong attraction for human settlement and subsistence activities in the cen
tral part of
Nigeria.
The study revealed three major issues, which include
:


1.

t
he natural boundary of the flood plain was not exceeded by the
2012
flood
water;

2.

All communities
inundated were
within the flood plain;

3.

The impact of the floods was exacerbated
d
ue to strong cultural affinity to the
flood plain by the affected communities
.
It is believed

that
,

the flood plain

settlements

are

ancestral
heritage; hence cannot be
abandon
ed

for fear of
flood
, as it may dis
please their ancestors.
It is also believed th
at,

flood
ing

was
not possible because it had not occurred in the
ir life time
, and even it does,
ancestral gods will
intervene and ensure its impacts were neutralized.


4.0
CONCLUSION


In this study, geospatial

techniques were
integrated for

the

mapping and

analysis of
2012

flood extent and vulnerable area
s
.
The study successively delineated the
flooded areas,

defined
the
critical vulnerable and risk zones, and estimated the
internally displaced persons (IDPs) by the flood in the study area
.

It is important

to note that, t
he

flooded
Niger
-
Benue valley
is
a
huge agricultural
and
natural resource endowment for the region, and has
for long been
a

strong attraction
for human settlement and subsistence activities in the central part of Nigeria
.
However, the s
ocio
-
economic and
cultural risk factors such as
poor infrastructure for
evacuation and
emergency management,
poverty,
cultural
/superstitious

belief
s

about
flood
,

had
actually

exac
erbated the general loss during
the
year 2012
flood disaster.


T
he strong
cultu
ral
affinity to the flood plain
s

as
ancestral heritages of most affected
communities

did not help matters
. Despite the predictions of unusual rainfall in 2012
by the Nigeria Meteorological Agency (NIMET), and the early warnings by the
National Emergency Ma
nagement Agency (
N
EMA) most affected communities relied
on history of

non
-
flood disasters


in their life time

and the cultural belief that,
“flood
plain settlements were

ancestral heritages,

and
if abandoned
for fear of flood will
displease

their ancestor
s

.

A combination this and other factors made the

flood
disaster very devastating, in which

Kogi State accounted for about 55.2%
while
Niger, Benue, Nasarawa and Kwara States accounted for about 14.2%, 19.8%,
5.2%, and 5.5% of the IDPs and inundated areas

respectively
.


4.1
Recommendations


The following are hereby recommended as a way forward in flood hazards and risk
mitigation in the study area.

i.

The development of flood contingency master plan for the flood plains in
Nigeria is imperative;

ii.

Communities s
hould be strongly discouraged from settling within the flood
plains;

iii.

There should be a comprehensive mapping and inventory of all flood plains in
Nigeria for proper planning, awareness and enlightenment of flood prone
communities in the country.

8
th

National GIS Symposium. Dammam. Saudi Arabia. April 15
-
17, 2013


12


iv.

The dredgi
ng of Rivers Niger and Benue should be implemented with

best
practice and several I
n
-
land ports and dams built
to partially
act

as
collectors

and reservoirs of excess river flow from the up
-
stream of the rivers.


Acknowledgements


Our appreciation goes t
o
the affected residents of parts of the Central States
of
Nigeria
(Kogi, Niger, Benue, Nasarawa, and Kwara
S
tates)

in the 201
2

flood
disaster
s

for cooperating and sharing their experiences on flood events in their
domains. Appreciations
goes
to the United N
ations Platform for Space
-
based
Information for Disaster Management and Emergency Response (UN
-
SPIDER) for
invoking the UN Charter and providing RADARSAT
, Infoterra SAR, SPOT

image
s

of
the flood

affected

area
s

in
Nigeria through the National Space Research

and
Development Agency (
NASRDA
)
, Abuja for Analysis and Emergency Response
Strategy. Thanks to USGS for freely making the SRTM DEM
available

and
our
great
appreciation to
LANCE MODIS Rapid Response Team

at
NASA GSFC

for the
pre

and
during

flood MODIS images of the affected parts of Nigeria made available
online.
Thanks to the National Emergency Management Agency (NEMA), Abuja, and
the Regional Centre for Training in Aerospace Surveys (RECTAS) Obafemi Awolowo

University, Ile
-
Ife, Nigeria for their management and technical roles in the field
evaluation, emergency response, mapping and analysis of the 2012 flood disasters
in Nigeria.

Thanks to NASRDA, Abuja for facilitating and supporting the UN
-
SPIDER
data with

ancillary datasets

(
NigeriaSat
-
1 and Settlement Maps of Nigeria
) and
logistics for the field work and mapping of the flood impacts.



References


ActionAid International (2006).
Climate change, urban flooding and the rights of the
urban poor in Africa:
Ke
y findings from six African cities. A Report by AAI,
October, 2006. Pp. 1
-
7

Associated Programme on Flood Management (
APFM)
, (2006). Social Aspects and
Stakeholder Involvement in Integrated Flood Management APF
M Technical
Document No. 4, Flood Management Policy Series © World Meteorological
Organization, 2006 ISBN: 92
-
63
-
11008
-
5. Pp. 1
-
100.

Balabanova, S, Vassilev, V (2010). Creation of flood hazard maps.
BALWOIS 2010
-
Ohrid, Republic of Macedonia
-
25, 29 May 201
0, available at
http://balwois.com/balwois/administration/full_paper/ffp
-
1560.pdf, last
assessed January 13, 2013.

Birkmann, J. (2006).

Measuring vulnerability to promote disaster
-
resilient societies:
Conceptual frameworks and definitions. UNU (6.125
_
9.25"
) TimesL pp. 7

54
;

1589_01

Bruzzone, L and P. Smits, P., (Eds) (2002)
Analysis of Multi
-
Temporal Remote
Sensing Images, 456p.
, World Scientific

Crichton, D. (1999) ‘‘The Risk Triangle’’, in J. Ingleton, ed., Natural Disaster
Management, London: Tudor Rose,

pp. 102

103.

European Commission (2007). Directive 2007/60/EC of the European Parliament
and of the Council of 23 October, 2007 on the assessment and management
of flood risks.
Official Journal of the European Union, L288/27
-
34
, available at
http://eurlex
.

8
th

National GIS Symposium. Dammam. Saudi Arabia. April 15
-
17, 2013


13


Few. R., Ahern M., Matthies, F. and Kovats, S. (2004) “Floods, Health and Climate
Change: AStrategic Review”.
Working Paper No. 63. Tyndall Centre for
Climate Change Research
.

Hassan M, A, Simon M. Berkowicz, and Olav Slaymaker (2000),
The Hydrology
-
Geom
orphology Interface
, International Association of Hydrological Sciences
(IAHS) Press, Publication 261: Wallingford, 326p,

Ikhuoria, I., Yesuf, G., Enaruvbe, G. O., and Ige
-
Olumide, O., (2012). Assessment of
the impact of flooding on farming communities in
Nigeria: A case study of
Lokoja, Kogi State Nigeria. Proceedings of
the Geoinformation Society of
Nigeria (GEOSON) & Nigerian Cartographic Association (NCA) Joint Annual
Workshop/Conference held at Regional Centre for Training in Aerospace
Surveys (RECTAS)
, Obafemi Awolowo University, Ile
-
Ife, Nigeria,19th

22nd
November, 2012.
Pp. 156
-
167

Je
b, D N and Aggarwal, S. P., (2008).
Flood inundation hazard modeling of the River
Kaduna using remote sensing and

geographic information systems.

Journal of
Applied Scie
nces Research,
4 (12), pages 1822


1833.

Jeyaseelan, A T, (1999), “Droughts and floods assessment and monitoring using
remote sensing and GIS”,
Satellite Remote Sensing and GIS Applications in
Agricultural Meteorology
, pages 291
-
313.

Kondolf, G. M and Piga
y, H. (2003).
Tools in Fluvial Geomorphology
, John Wiley
&Sons. 696p.

Kwak, Y and Kondoh, A (2008), “A study on the extraction of multi
-
factor influencing
floods from RS image and GIS data; a case study in Nackdong Basin, South
Korea”,
The International Ar
chives of The Photogrammetry, Remote Sensing
And Spatial Information Sciences
,
ISPRS Congress Beijing 2008
,
37, Part B8,
Commission VIII, pages 421
-

426, available at
http://www.isprs.org/proceedings/XXXVII/congress/8_pdf/2_WG
-
VIII
-
2/50.pdf,last assessed J
anuary 7, 2013.

Li, Jiren and Huang, Shifeng (2002).
Application of Remote Sensing in the
Management of Hydrology and Water Resources.
Institute of Water
Resources and Hydropower Research, Beijing 100044,China

Mansor, S., Shariah, M.A, Billa, L, Setiawan,
I and Jabar, F., (2004). Spatial
technology for natural risk management.
Disaster Prevention and
Management
, vol. 13, no. 5, pp. 364


373, 2004.

MunichRe, 2005. Megacities


Megarisks: Trends and Challenges for Insurances
and Risk Management,
http://www.
munichre.com/publications/302
-
04271_en.pdf

NASA Images courtesy
LANCE MODIS Rapid Response Team

at NASA GSFC.
Caption by Michon Scott. Instrument: Terra


MODIS.
www.nasa.or
g


Ojigi, M. L., (2010). Flood Hazard and Risk Mapping of Birnin Kebbi and Environs,
Using Geospatial Techniques.

Journal of Geographic Information Science
Vol.1 no.1 (Maiden Edition), 2010. A technical/scientific publication of
Geoinformation Society of
Nigeria (GEOSON) (in press).

Ojigi, M. L. and Shaba, A. H., (2012).
Integration of Synthetic Aperture Radar (SAR)
Imagery and Digital Terrain Model for Determining Flood Water Threshold in
Sokoto and Environs, Nigeria.

Proceedings of
the Geoinformation Soc
iety of
Nigeria (GEOSON) & Nigerian Cartographic Association (NCA) Joint Annual
Workshop/Conference held at Regional Centre for Training in Aerospace
Surveys (RECTAS) Obafemi Awolowo University , Ile
-
Ife, Nigeria,19th

22nd
November, 2012.
Pp. 291
-
303

8
th

National GIS Symposium. Dammam. Saudi Arabia. April 15
-
17, 2013


14


Ologu
noris
a, T. E. and Abawua, M. J., (2005).
F
lood risk assessment: a review.

Journal
of

Appl. Sci. Environmental Management
, 9 (1), pages 57


63.

Onana, V. P., Rudant, J.P. Trouve, E., Mauris, G., Laporte, N. T., Walker, W., (n.d).
A Flood Hazard Risk Assess
ment Map in Growing Urban Areas by Integrating
Remote Sensing and DEM Data. 2pp.

UN/ISDR (International Strategy for Disaster Reduction) (2004) Living with Risk: A
Global Review of Disaster Reduction Initiatives, 2004 version, Geneva: UN
Publications.

Unit
ed Nations Development Programme (UNDP) (2004) Reducing Disaster Risk: A
Challenge for Development. A Global Report, New York: UNDP


Bureau for
Crisis Prevention and Recovery (BRCP), available at
http
://www.undp.org/bcpr/disred/rdr.htm