DISCUSSION PAPER: HIGHLIGHTS OF RECENT FLOODS IN NIGERIA
By
Salihu Mustafa
Flood can be defined as an abnormal progressive rise in the water level of a river/stream
leading to a crest and then followed by a slower recession such that, the process may result
in the overflowing of the river/stream with the subsequent inundation of the banks.
(Derived from Linsley , 1942and UNESCO-WMO, 1974)
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There are predominantly four flood types observed in Nigeria
Urban flooding- 41%
Flash Flooding – 11%
River Flooding- 43%
Dam flooding -5%
These are shown in Fig. 1
Dam flood
5%
Flash flood
11%
Urban flood
41%
Dam flood
Flash flood
River flood
Urban flood
River flood
43%
Fig.1 Classification of floods in Nigeria (NIHSA Flood Outlook, 2013)
--------------------------------------------------------------------------------------------------------Technical Workshop On: Toward a Consensus on Flood Risk Hotspots in Nigeria
Under a Changing Climate, World Bank Office, Abuja, Tuesday Feb 18, 2014.
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2. Rivers Benue and Niger constitute Major River flooding although the two rivers originate
outside the boundary of Nigeria.
3. In the six geopolitical zones, the floods the percentage LGAs flooded vary from zone to zone;
as high as 40% in South-South zone and only 2% in the South-East zone. The distribution is as
shown in the Table below and Fig.2
100%
90%
80%
70%
60%
%LGAs not under threat
of flood
50%
%LGAs under threat of
flood
40%
30%
20%
10%
0%
NE
NW
NC
SW
SE
SS
Fig.2 Percentage no. of LGAs under threat of flood in each of the six
geopolitical zones (derived from NIHSA data on Flood Outlook in 2013)
ZONE
% LGAs
under threat
of floods
% LGAs not
under threat
of floods
Total
NE
28
NW
19
NC
27
SW
11
SE
2
SS
32
72
81
73
89
98
68
100
100
100
100
100
100
Table1. Showing percentage of LGAs under threat in each of the six geopolitical zones
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4. The number of LGAs in each zone under threat of floods as percentage of total LGAs
in Nigeria is distributed as follows and shown in Fig3.
% LGAs under
threats of floods in
the zone
NE
20
NW
22
NC
21
SW
10
SE
2
SS
25
Total
100
NE
21%
ss
25%
NE
NW
NC
SE
1%
SW
SE
SW
10%
NW
22%
ss
NC
21%
Fig.3 Percentage of number of LGAs under threat of flood in each zone over
total number of LGAs in Nigeria (derived from NIHSA data on Flood Outlook in 2013)
5. Flood management strategies
These can be structural or non-structural
Structural strategies
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Modifying the flood event by erecting structures such as:
Levees, dykes and embankments
Creating flood ways and channel improvements
Spurs and revetments
Reservoirs and detention ponds
Catchment treatments and afforestation
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
Incorporate climate change in the design of parameters of water resources structures like
dams and channels.
Non-structural strategies
a. Accept to adapt to floods and minimize damage that there is no complete immunity.
b. Effective flood forecasting and warning
c. Invest in research to improve understanding of the statistics of extreme events, reliability of
flood defences and risk analysis.
d. Improvement on flood forecast such that, the variation between forecast and corresponding
observation is not more than a set threshold level- say 20%
e. Flood proofing- providing raised platforms above flood level to give shelter to human beings
and animals during floods. Also, filling lowland areas to level above flood level.
f. Flood plain zoning- Prepare maps of flood plain zones, preferably, of the order 1: 15,000
with contour interval 0.3-0.5m to help to regulate land use in flood plain zones.
Demarcate areas to be covered by flood of 1 in 100 year return period- Inland Waterways in
Nigeria prohibits settlement or payment of compensation within this zone. Also, demarcate
1 in 1,000 year return floods.
g. Establishing disaster preparedness and rapid response committee at
federal, state and local government level, that would plan on how relief agencies are to be
involved in evacuation, recue, food and drinks distribution, health care, erection of
temporary shelters, providing clothing and financial assistance and repair and rebuilding of
damaged structures. Itemize requirements in advance by communities such as
Shelter to be constructed.
h. Supply of boats for evacuation of flood victims and provision of food items and other relief
materials that would be needed.
i. Supply of Mini-water treatment plants treating about 1,000Litres/hour ( costing US$2,0003,000)
j. Flood Insurance scheme- Evolve insurance scheme to cover losses to buildings, crops,
livestock, fisheries, rural industries and loss of life. Government might be involved in
providing reinsurance to insurance bodies.
k. Monitoring - Monitoring scheme to be in place to assess previous rescue measures and likely
improvements on future rescue operations
l. Need to develop technology and kills to plan, design, implement and monitor strategies
toward hazard risk reduction.
Annex1 - President Obama proposes $1 billion investment to mitigate the impact of climate
change- likely lesson for Nigeria.
Conclusion
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River flooding and urban flooding constitute most of the floods experienced in Nigeria.
River flooding is predominantly on the banks of Rivers Benue and Nigeria which both
originate outside the borders of Nigeria. Thus, flood management strategies to be drawn up
should involve the bordering countries and the hinterland states the rivers cross.
LGAs affected by floods can be grouped into the six geopolitical zones for purposes of
planning and ease of project implementation.
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Regional flood frequency maps can be derived either for the eight hydrological units or six
geopolitical zones.
To combat floods investment should be made in both structural and non-structural
strategies which should include capacity building mechanism.
ANNEX1-Obama proposes $1 billion climate protection fund
Washington (AFP) 2/14/2014 6:48:41 PM-Brendan Smialowski/AFP
US President Barack Obama (2ndL) talks with Rep. Jim Costa (2ndR) while walking to Air Force One at
Andrews Air Force Bast February 14, 2014 in Maryland
Highlights
President Barack Obama will Friday propose a $1 billion dollar fund to mitigate the impact of climate
change, as he inspects farmland parched by drought in California.
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He will propose the investment in his 2015 budget that will be released next month -though it is
"We've always had severe storms, but instead of hundred-year storms that happen once a
hundred years, we're having hundred-year storms that happen every other year or every
five years."
The new Climate Resilience Fund is intended to finance research into better understanding
of projected impacts of climate change and how to better protect communities and
infrastructure.
It is also designed to help vulnerable communities plan and prepare for the impacts of
climate change and to encourage local measures to reduce future risk and to fund new
resilient technologies and infrastructure to combat a warming climate.
Around 90 percent of California is reported to be experiencing severe to exceptional
drought.
The drought emergency has also sparked wildfires and prompted Governor Jerry Brown to
ask Californians to cut their water use by 20 percent.
Obama will pledge to implement $100 million in livestock disaster assistance for California
producers contained in a recently passed agriculture bill.
He will also highlight $15 million in conservation funding for extreme drought areas in
California, Texas, Oklahoma, Nebraska, Colorado and New Mexico.
A further $5 million will be provided for emergency watershed protection for California,
among other measures which also include a mandate for federal facilities to use less
water.
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