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A review and critical analysis of the efforts towards urban flood risk management in the Lagos region of Nigeria


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Urban flooding has been and will continue to be a significant problem for many cities across the developed and developing world. Crucial to the amelioration of the effects of these floods is the need to formulate a sound flood management policy, which is driven by knowledge of the frequency and magnitude of impacts of these floods. Within the area of flood research, attempts are being made to gain a better understanding of the causes, impacts, and pattern of urban flooding. According to the United Nations office for disaster reduction (UNISDR), flood risk is conceptualized on the basis of three integral components which are frequently adopted during flood damage estimation. These components are: probability of flood hazard, the level of exposure, and vulnerabilities of elements at risk. Reducing the severity of each of these components is the objective of flood risk management under the UNISDR guideline and idea of “living with floods”. On the basis of this framework, the present research reviews flood risk within the Lagos area of Nigeria over the period 1968–2012. During this period, floods have caused harm to millions of people physically, emotionally, and economically. Arguably over this period the efforts of stakeholders to address the challenges appear to have been limited by, amongst other things, a lack of reliable data, a lack of awareness amongst the population affected, and a lack of knowledge of flood risk mitigation. It is the aim of this research to assess the current understanding of flood risk and management in Lagos and to offer recommendations towards future guidance.
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Nat. Hazards Earth Syst. Sci., 16, 349–369, 2016
© Author(s) 2016. CC Attribution 3.0 License.
Review article: A review and critical analysis of the efforts towards
urban flood risk management in the Lagos region of Nigeria
U. C. Nkwunonwo1,2, M. Whitworth2, and B. Baily3
1Department of Geoinformatics and Surveying, University of Nigeria, Enugu Campus, Nigeria
2School of Earth and Environmental Sciences, University of Portsmouth, Portsmouth, UK
3Department of Geography, University of Portsmouth, Portsmouth, UK
Correspondence to: U. C. Nkwunonwo (
Received: 28 April 2015 – Published in Nat. Hazards Earth Syst. Sci. Discuss.: 16 June 2015
Revised: 18 January 2016 – Accepted: 22 January 2016 – Published: 5 February 2016
Abstract. Urban flooding has been and will continue to be
a significant problem for many cities across the developed
and developing world. Crucial to the amelioration of the ef-
fects of these floods is the need to formulate a sound flood
management policy, which is driven by knowledge of the fre-
quency and magnitude of impacts of these floods. Within the
area of flood research, attempts are being made to gain a bet-
ter understanding of the causes, impacts, and pattern of ur-
ban flooding. According to the United Nations office for dis-
aster reduction (UNISDR), flood risk is conceptualized on
the basis of three integral components which are frequently
adopted during flood damage estimation. These components
are: probability of flood hazard, the level of exposure, and
vulnerabilities of elements at risk. Reducing the severity of
each of these components is the objective of flood risk man-
agement under the UNISDR guideline and idea of “living
with floods”. On the basis of this framework, the present re-
search reviews flood risk within the Lagos area of Nigeria
over the period 1968–2012. During this period, floods have
caused harm to millions of people physically, emotionally,
and economically. Arguably over this period the efforts of
stakeholders to address the challenges appear to have been
limited by, amongst other things, a lack of reliable data, a
lack of awareness amongst the population affected, and a lack
of knowledge of flood risk mitigation. It is the aim of this re-
search to assess the current understanding of flood risk and
management in Lagos and to offer recommendations towards
future guidance.
1 Introduction
Flood events and impacts in recent times have arguably been
unprecedented and affected the lives of hundreds of mil-
lions of people across the world. These impacts have been
shared by both developed and developing countries (DCs)
with rapid urban expansion taking place in many flood-prone
areas. Concerns for flooding and the associated human im-
pacts are clearly of global significance, especially when al-
lied with the fears of climatic change and associated changes
in rainfall events and sea level rise (Kundzewicz et al. 2014).
The rapidly growing urban environments in many areas cor-
respond with a lack of urban planning strategies, the deterio-
ration and lack of capacity of urban drainage infrastructure
and an increased rate of development on floodplains (Gill
2004; CII, 2001). Additionally, the increasing densities of
populations (particularly in the urban areas of most DCs such
as Nigeria), alongside the poor level of awareness and the
limited efforts of many stakeholders towards flood risk re-
duction are critical issues undermining possible efforts to-
wards addressing the hazard (Action Aid, 2006; McMichael
et al., 2006; Raaijmakers et al., 2008). The present research
attempts to clarify these issues using a synthesis and analysis
of available historical flood data in the Lagos area of Nigeria,
spanning the period 1968 to 2012. This research also reviews
the current status and awareness of pluvial flood risk within
Lagos and makes recommendations to help improve the man-
agement of these events.
Published by Copernicus Publications on behalf of the European Geosciences Union.
350 U. C. Nkwunonwo et al.: A critical review of Lagos urban flood risk management
2 Description of the Lagos metropolis of Nigeria
The Lagos metropolis is a densely populated low-lying
coastal area in the southwestern part of Nigeria, West Africa.
The city is located within geographical coordinates of 3.1 to
3.4E longitude and 6.5 to 6.8N latitude and covers a land
area of approximately 1100km2(or 425 sq. miles). It is bor-
dered in the south by the Atlantic Ocean (see Fig. 1). With
a dense network of roads and buildings, and several inland
waterways including the Lagos Lagoon which empties into
the Atlantic, the conurbation serves as a major hub for trans-
portation, tourism, and economic activities in Nigeria. With
a population of over 20 million people (LSG, 2012), the La-
gos metropolis is the biggest city in Nigeria, (although the
smallest land area), the second largest city in Africa, and the
seventh largest city in the world. The population growth rate
in the Lagos metropolis is estimated at 3.2% (World Bank,
2013). Against this background, the United Nations predicts
that Nigeria will be one of the eight countries expected to
account collectively for half of the total population increase
in the world from 2005 to 2050, and will by 2100, have a
population of between 505 million and 1.03 billion (United
Nations, 2004). High population density is a major impasse
in the Lagos region, subjecting the area to lack of space for
the myriad of human activities, which often manifests itself
in muddled human settlements, overcrowding, slum envel-
opments, pollution, illegal structures, and other social and
environmental disorder. These factors, either singularly or in
combination, have the potential to increase exposure to haz-
ard, especially the risks associated with pluvial urban flood-
ing events.
3 Flooding in Lagos – frequency, causes, and impacts
Flooding and flood risk management are issues of grave sig-
nificance in Lagos (Aderogba, 2012a, b). It is clear from
previous studies (for example, Ajibade et al. 2013, 2014;
Adelekan, 2013), that flooding in the area can be devastat-
ing, affecting hundreds of thousands of people and causing
considerable economic damage. A typical example is the
July 2011 flooding event, which affected approximately 5
thousand people and resulted in about 25 deaths. The direct
economic losses resulting from the event totalled about 50
billion Nigerian naira (i.e. USD 250million). Public utili-
ties including road networks, bridges, and schools were de-
stroyed. In addition, houses collapsed, private homes were
submerged, and several cars were swept away by flood water
(IFRC, 2011; Oladunjoye, 2011).
3.1 Frequency of occurrence
From a historical perspective, Lagos has always been sus-
ceptible to various types of flooding which are well docu-
mented from the 1960s onwards (Odunuga, 2008; Oyebande,
1974; Etuonovbe, 2011). However, in recent years pluvial
flooding events (rainfall-related), have arguably been more
widespread (Olajuyigbe et al., 2012). With the exception
of 1973, the drought year, flooding in Lagos has occurred
annually (usually between July and October rainy season)
with an increasing intensity and an increased severity of im-
pacts from 1960 onwards (Oyebande, 1974). According to
FME (2012), Lagos is one of the few locations in Nigeria
with more frequent flooding events (see Fig. 2). A number
of floods have occurred in the Lagos area, although keep-
ing track of events in the Nigerian context is challenging due
partly to lack of relevant data collection capacities. As a re-
sult, data relating to hydrodynamics and historical flooding
events are often lacking (Ajibade et al., 2013). According to
previous studies, more severe flooding has been recorded in
select areas of Lagos including Lagos Island, Apapa, Ikeja,
Mushin, Surulere, and parts of Ikorodu (Oyebande, 1974;
Odunuga, 2008). There is no clear explanation for this pe-
culiar circumstance, but it seems to follow a pattern of spa-
tial and temporal distribution of rainfall within and around
Table 1 shows a summary of major flooding events and
associated consequences in the Lagos metropolis of Nige-
ria from 1968 to 2012. These data which appear to repre-
sent generalized flooding situations were obtained from a
wide range of sources including EM-DAT and the Nigerian
FME (Federal Ministry of Environment). It is argued that
the conclusions that can be drawn about flooding in Lagos
from these data sets relate to events of higher magnitudes
and return periods (Guha-Sapir et al., 2013). Only journalis-
tic and non-quantitative evidence is available for lesser im-
pacts and more frequent flooding events (see for example,
IFRC, 2012). The problem with these forms of evidence is
that they often do not have ethical and empirical groundings.
For most of the events considered, data relating to flood du-
ration and impacts in terms of number of people displaced,
mortality, and economic losses were not available. On the
basis of this inconsistency, the effectiveness of flood man-
agement policies is being queried (Adelekan, 2015). In many
cases, different types of flood damage were aggregated. In-
deed, this situation adversely affects accurate flood damage
estimation since a critical understanding of Lagos flood risk
in the context of flood damage typology is difficult.
To qualitatively identify risk levels in this area, an ap-
proach used in the 2005 World Bank Hotspot project was
adopted (Dilley et al., 2005). In this approach, records of
flood events and affected areas were coupled with the pop-
ulation density of the local enumeration areas in Lagos and
mapped in a GIS. The result of this analysis as shown in
Fig. 3, indicates that Ajeromi-Ifelodun and Mushin areas are
at a higher risk of flooding than other areas. This approach,
regardless of its simplicity, offers a potentially valuable in-
sight into flooding patterns in Lagos. However, much uncer-
tainty lies within the results and this suggests the need for
more detailed research that will investigate the flood risk lev-
Nat. Hazards Earth Syst. Sci., 16, 349–369, 2016
U. C. Nkwunonwo et al.: A critical review of Lagos urban flood risk management 351
Figure 1. The Lagos metropolis of Nigeria. Inset shows the location of Lagos State in Nigeria.
els at Lagos using a more detailed quantitative or qualitative
data set.
3.2 Causes of flooding
Over the past 2 decades, the causes of flooding in Lagos
have received significant attention in the literature (Ayoade
and Akintola, 1980; Action Aid, 2006; Adeloye and Rus-
tum, 2011; Adelekan, 2013; Aderogba, 2012a; Oshodi, 2013;
Ajibade et al., 2013, 2014; Soneye, 2014). Debates aris-
ing from the literature indicate that Lagos floods are mainly
the consequences of climate-change-induced short-duration-
high-intensity or long-duration-low-intensity rainfall (Hous-
ton et al., 2011). This is unsurprising considering that climate
change has arguably influenced regional precipitation pat-
terns in recent history. Odjugo (2006) concluded that there
are now more high-intensity short-duration rainfall events
and more low-intensity long-duration rainfall events than
there were 3 decades ago. Other factors have also been in-
vestigated with reference to the causes of these floods in
Lagos. These include the topography of the area, land use
(LU) and land cover (LC) modifications, and influence of
canals, lagoons, and beaches (Aderogba, 2012a; Aderogba et
al., 2012; Odunuga, 2008). Other factors considered are ur-
banization and population growth, poor urban planning, and
poor environmental management and the indiscriminate dis-
posal of solid waste (Lamond et al., 2012; Adeloye and Rus-
tum, 2011). It is also suggested that tidal and co-tidal influ-
ences and frequent incursion from the Atlantic into the low-
lands during heavy storms also play important roles (Ojin-
naka, 2013).
These factors (schematized in Fig. 4), seem to influence
the occurrence of the hazard and the exposure of elements
at risk. However, in relation to the vulnerabilities of social
systems to flooding in the area, the development of slum set-
tlements and poor perception of flooding among local com-
munities, urban residents and the general public are critical
factors (Agbola and Agunbiade, 2007; Nkwunonwo, 2013;
Ayoade and Akintola, 1980; Odunuga et al., 2012; Oloke et
al., 2013; BNRCC, 2008).
3.3 Impacts of flooding
To date, flooding in Lagos is characterized by severe conse-
quences, which raise concerns about a lack of early warning
and evacuation systems. Impacts from flooding (as illustrated
in Fig. 5) are compounded by population density and the up-
ward trends of urban growth in the area (Aderogba, 2012b).
Also, flood water depth, inundation extent and duration as
well as water flow velocity play contributory roles. The gen-
eral impacts (such as displacement from homes, mortality,
physical injuries, disruption of economic activities, destruc-
tion of urban infrastructure, and submergence of buildings)
that relate to social systems directly have been extensively
considered in the literature (Ugwu and Ugwu, 2013; Adi-
gun et al., 2013; Ajibola et al., 2012; Aderogba, 2012b; Ola-
juyigbe et al., 2012). However, there are reports that Lagos
flooding causes severe additional impacts including the loss
of social values, spread of vector-borne diseases, as well as
air and water pollution (Adelekan, 2010; Olajuyigbe et al.,
2012; Bashir et al., 2012). Nat. Hazards Earth Syst. Sci., 16, 349–369, 2016
352 U. C. Nkwunonwo et al.: A critical review of Lagos urban flood risk management
Figure 2. Spatial distribution of areas affected by extreme floods in Nigeria between 2000 and 2012. Adapted from the Federal Ministry of
Environment (2012).
Figure 3. Flood risk levels in the Lagos area qualitatively determined by coupling population density with list of flooding events and locations.
Nat. Hazards Earth Syst. Sci., 16, 349–369, 2016
U. C. Nkwunonwo et al.: A critical review of Lagos urban flood risk management 353
Figure 4. Main causes of urban flooding in the Lagos area of Nigeria showing global climate change, poor urban planning, urbanization, and
anthropogenic activities.
Olajuyigbe et al. (2012) report that flood hazard increases
city-wide poverty as a result of the farmlands which are de-
stroyed and essential services which are often interrupted.
Adelekan (2010) investigated these impacts using four poor
urban communities in Lagos as case studies and identified
three significant scales: individual, household, and commu-
nity. At the individual scale, the reluctance of friends and
family to visit one another while in flooded houses affects
social relationships. This has broad adverse implications
on community lifestyle and further compounds depression
among flood victims in Lagos. Food insecurity is equally an
important issue at this scale as food items stored in individ-
ual homes are often lost during flooding. In addition, there
can be numerous health impacts including chronic skin infec-
tions from exposure to contaminated environmental systems
and increased effects on those with an already poor health
Household and community scales of impacts are mainly
indicated by the secondary effects of flooding in Lagos.
Household impacts include deterioration of building qual-
ity, intrusion of contaminated water into apartments, lack of
good drinking water, and loss or damage to household prop-
erties including sanitation facilities. The community impacts
include an unclean environment, disruption of movement,
and damage to public utilities. Urgent needs arise where
community schools were flooded and schooling for children
has been interrupted. This is an important issue within the
context of human development. In many other DCs where it
is also applicable, community leaders and the local authori-
ties have often instigated measures to ensure that children’s
schooling is not interrupted despite the magnitude of flood-
ing. In Bangladesh for example, a strategy known as “float-
ing schools” in which classrooms are constructed on boats is
being put in place during flooding (Huq and Aslam, 2003).
This enables provision of uninterrupted education for chil-
dren who have been impacted and whose education has been
disrupted by flood catastrophes.
The impacts of flooding in Lagos also trigger concerns for
environmental management, urban sustainability, and the de-
velopment, governance, and the vulnerability of urban res-
idents and local communities. Other factors of concern are
humanitarian needs and services, especially primary health
delivery (Soneye, 2014; Ajibade, 2013; Lamond et al., 2012).
Needless to say, concerns for solid waste management are
crucial as long as the indiscriminate dumping of wastes into
drainage systems remains prevalent within Lagos. One ex-
ample of this is the water sold in polythene sachets which
is the major source of drinking water for residents. It is per-
ceived that many residents dispose of the containers which
end up in drainage facilities. Being a non-degradable waste, Nat. Hazards Earth Syst. Sci., 16, 349–369, 2016
354 U. C. Nkwunonwo et al.: A critical review of Lagos urban flood risk management
Figure 5. Some flooding scenes examples in the Lagos metropolis of Nigeria: (a) living room submerged by flood water, (b) residential
building submerged, (c) local community affected by flood waters, and (d) expressway overwhelmed by flood water. Source: Online images
of flooding in Lagos, Nigeria.
it accumulates over time and blocks these drainage facilities.
Unfortunately, little has been done to address such an impor-
tant issue in flood control management.
4 Present research and gaps in knowledge
Despite the frequency of occurrence, causes, and severity
of impacts of Lagos urban flooding alongside the under-
standing of a potentially increased risk in the future a bet-
ter understanding of flooding in Lagos is lacking. Whilst
most of the data relating to these impacts are at local levels
and limited to small geographical areas, wide-ranging cross-
disciplinary intervention measures are constrained. Lack of
data and poor data scale present an important limitation to
comprehensive urban flood impact assessment and manage-
ment. Flood risk management efforts in Lagos considered
in the light of global current flood risk management prac-
tices (see Sect. 5) reveals significant gaps. A number of non-
structural approaches which promote flood risk assessment
and management are frequently ignored. Efforts to manage
and assess flood risk in Lagos are aimed at both prevention
and control of flooding. Moreover, such efforts have been
unprecedented in Nigeria and clearly demonstrate a prac-
tical commitment to fighting the flood hazard (Njoku and
Udeagha, 2013; Obeta, 2014). However, results from vari-
ous studies which highlighted the increasing vulnerabilities
to flooding indicate that such efforts have so far been of little
assistance to the victims of flooding.
The problems of a lack of data and poor data scale in Lagos
are exacerbated by the general lack of funds and inadequate
access to improved technology alongside a lack of political
will (Nkwunonwo et al., 2014; Adeloye and Rustum, 2011).
Unfortunately, the level of existing knowledge regarding the
state of affairs is unsatisfactory and fails to assist in provid-
ing a potential solution to ways of reducing the hazard or
its impacts on human populations. The more critical and dis-
turbing scenario is that the Lagos area is a fast-growing city
within which a great deal of the population currently lives
within areas prone to flooding. Locally, the majority of these
areas are slums which provide provisional dwelling places
to poor urban residents. Adelekan (2010) argued that these
residents often do not have the capacity to cope with flood
hazard or the ability to quickly recover from losses. More-
over, the vast spatial distribution of such flood-prone areas
in Lagos increases the exposure of the human population to
flooding. A clearer picture taken from a global and regional
perspective shows that Lagos is among the top 20 cities with
Nat. Hazards Earth Syst. Sci., 16, 349–369, 2016
U. C. Nkwunonwo et al.: A critical review of Lagos urban flood risk management 355
Table 1. A summary of major flooding events and associated threats in the Lagos metropolis of Nigeria from 1968 to 2012. Source: EM-DAT (2014), FME (2012) and published works.
1 Oct 2012 Lagos city* Many days, unspecified Heavy rain Thousands > 50 Millions, unspecified Many, including interruption of traffic and other activities
2 Jul 2011 Lagos island, Mainland, Mushin 2 days Heavy rain 10 000 100 Millions, unspecified Many
3 Oct 2010 Lagos island, Apapa, Kosofe, Many days, unspecified Heavy rain Thousands 20 Millions, unspecified Manyincluding interruption of traffic and other activities
4 Jul 2009 Lagos city* Many days Heavy rain Many Nil Millions, unspecified Many
5 Oct 2008 Lagos city* N/A Heavy rain Not specified No data Millions, unspecified Manyincluding interruption of traffic and other activities
6 Aug 2007 Ikorodu, Kosofe and Abeokuta 15 Heavy rain 5000 17 Millions, unspecified 5000
7 Jul 2005 Lagos city 5 Heavy storm 3000 25 Millions N/A
8 Jun 2004 Lagos city 2 Heavy rain 1000 Nil Millions Drainages
9 Jul 2002 Lagos city 3 Heavy rain 200 2 Millions Many
10 Jun, Jul, Sep 2000 Victoria Island and Ikoyi 2 Brief Torrential Rain 500 Nil Millions, unspecified Tens of thousands
11 May, Jun, Jul 1999 Mushin and Idiaraba N/A 70 000000
12 Jul 1990 Lagos city 2 Heavy rain 3000 5 Thousands Many, not specified
13 Jul 1990 Lagos city 2 Heavy rain 500 Nil N/A Hundreds of inhabitants
14 Jun 1974 Idiaraba, Ikorodu, Surulere, and Yaba Many days, unspecified Heavy rain Thousands Nil N/A
15 Jun 1972 Lagos Island N/A Heavy rainfall Not specified Nil N/A Traffic was disrupted, few houses
16 Jul 1971 Lagos Island 5 Heavy rainfall Not specified Nil N/A Traffic was disrupted, few houses
17 Jul 1970 Lagos Island N/A Winds, accompanied by short-duration, Nil Nil 5000 Few
high-intensity rain
18 Jun 1969 Surulere and Yaba 10 Short-duration, high-intensity rain Nil Nil N/A Many, not specified
19 Jun 1968 Lagos Island and Ijora. N/A Heavy storm Nil Nil 6000 Traffic was disrupted, Few houses
Grouped instead of treating as separate variables due to lack of data. N/A: Not available. Nil: No information.
increasing numbers of the present and future population ex-
posed to flooding (see Table 1). Within such an environment,
destruction of biodiversity and depletion of ecosystem func-
tions to earn a livelihood are common practices. Given the
issues of coping capacity and resilience which remain unre-
solved for the burgeoning vulnerable population, sustainable
development under such circumstances is difficult and almost
The present research attempts to address the challenges of
flooding within and around Lagos through a review of litera-
ture and flood information covering the hazard in the area and
how it has so far been managed. Available historical flood
data in the area, spanning the period 1968 to 2012, were syn-
thesized and analysed. These data were obtained from vari-
ous online databases (for example: NEST, 1991; Guha-Sapir
et al., 2013) and published data on historical flooding in La-
gos, Nigeria. Sourcing data from a wide range of databases is
an attempt to clarify the issue of lack of flood data which cre-
ates significant gaps in knowledge relating to flood manage-
ment efforts in Lagos. The research discusses the challenges
faced by Lagos in managing and reducing flooding impacts.
It contextualizes the current situation and puts forward rele-
vant recommendations for more effective remedies to allevi-
ate the threats of flooding in the area. Ultimately, it is argued
that the lack of more robust techniques such as flood mod-
elling and assessment of vulnerability accounts for a stark
limitation in the efforts towards addressing the challenges of
flooding in the area. In particular, the importance of flood
modelling in flood risk reduction and the need for it to be
included in the present and future efforts at reducing the im-
pacts of flooding are emphasized. This research in general
and the recommendations in particular are driven by three
key aims: firstly, to understand the unique situation which
exists in Lagos in relation to flooding; secondly, to align the
focus of flood risk reduction in the Lagos area with that of
more developed countries such as the US, the Netherlands,
and the United Kingdom; and finally, to suggest measures
for possible improvements.
5 Flood risk management: the general concept
In recent times, a shift from flood hazard control to flood
risk reduction has been found necessary (Samuels et al.,
2006). This is due to the inexorable nature of the haz-
ard and the general perception that climate change, demo-
graphic, and economic activities would influence regional
and global occurrences and consequences of flooding in the
future (Kundzewicz et al., 2010, 2014). The importance of
this new framework lies in the way in which risk is contex-
tualized, which enables strategic and adaptable policies to be
easily formulated.
There are various interpretations of the concept of risk in
the literature (see for example Renn, 2008) and this com-
plicates a cross-disciplinary approach to risk reduction. An Nat. Hazards Earth Syst. Sci., 16, 349–369, 2016
356 U. C. Nkwunonwo et al.: A critical review of Lagos urban flood risk management
Table 2. Top 20 countries ranked in terms of population exposed to coastal flooding in the 2070s, including both climate change and socio-
economic change and showing present-day exposure. (Source: Nicholls et al., 2008; OECD, Paris.) (Highlight of Nigeria is by the authors.)
Rank Country Urban Exposed population Exposed population
agglomeration (current) (future)
1 India Calcutta 1929000 14014000
2 India Mumbai 2787000 11 418000
3 Bangladesh Dhaka 844000 11135 000
4 China Guangzhou 2718 000 10333 000
5 Vietnam Ho Chi Minh City 1931 000 9 216000
6 China Shanghai 2353 000 5 451000
7 Thailand Bangkok 907000 5 138 000
8 Myanmar Rangoon 510 000 4965 000
9 USA Miami 2003 000 4 795000
10 Vietnam Hai Phòng 794 000 4 711000
11 Egypt Alexandria 1330 000 4 375000
12 China Tianjin 956000 3790 000
13 Bangladesh Khulna 441000 3 641 000
14 China Ningbo 299000 3 305 000
15Nigeria Lagos 357000 3229 000
16 Cote d’ivoire Abidjan 519 000 3 110000
17 USA New York 1 540000 2931 000
18 Bangladesh Chittagong 255000 2866 000
19 Japan Tokyo 1110 000 2521 000
20 Indonesia Jakarta 513000 2 248 000
agreed perception of risk is still lacking despite decades of
research. In an attempt to address this conceptual conflict,
the United Nations in 1992 proposed a seminal definition:
“risk is the expected loss (of lives, persons injured, property
damaged, and economic activity disrupted) due to a particu-
lar hazard for a given area and reference period”. In addition,
the United Nations International Strategy for Disaster Reduc-
tion defined risk as the combination of probability of a haz-
ard and its negative consequences (UNISDR, 2004). Within
these frameworks, hazard-specific and place-based concepts
of risk are highlighted (see for example Penning-Rowsell and
Chatterton, 1997).
Regardless of conceptual disparity, on the basis of haz-
ard, risk is too often hypothesized as the product of hazard
and its consequences (Samuels, 2000; Samuels et al., 2006;
De Wrachien et al., 2011; Solín and Skubincan, 2013). This
concept of risk generally embodies three components which
are considered fundamental to various methods used today
in flood risk assessment and management and they include:
“probability of hazard occurrence”, “exposure”, and “vulner-
abilities” of elements at risk. Global current flood risk man-
agement practices or “best practices” in flood risk manage-
ment can be identified in a wide range of sources (see for
example Ashley et al., 2007; Fratini et al., 2012; Sayers et
al., 2013) which aim to reduce the likelihood and/or the con-
sequences of floods. The idea of “living with floods rather
than fighting them” is the underlying framework. This phi-
losophy tends towards a policy whereby societies adapt to
floods by being prepared and having the right attitude to-
wards damage reduction (van Ogtrop et al., 2005). It stems
from three key considerations: (1) the limitations or fail-
ures of traditional flood control structural measures; (2) the
need for a people-friendly means of tackling flooding; and
(3) the goal to lessen all impacts of extreme floods while
at the same time exploiting all benefits of ordinary floods
(UNISDR, 2004; Di Baldassarre and Uhlenbrook, 2012).
These considerations are often perceived in the context of
a holistic management cycle which covers prevention, pro-
tection, preparedness, emergency response, recovery, and
lessons learned (Samuels, 2000). Within this framework, a
sound understanding of flooding, accurate and actionable as-
sessment of flood hazard and flood risk, knowledge-based de-
cision making, and strong political leadership are indispens-
able (UNISDR, 2004). As a result, integrated approaches
which combine structural and non-structural measures are
extensively applied (EC, 2004; Pitt, 2008; Kazmierczak and
Carter, 2010; Sayers et al., 2013).
Structural measures which aim at reducing the occurrence
of flood hazard are technically based and involve channeliza-
tion and the use of natural and man-made barriers to contain
waters in rivers and seas. Non-structural measures have the
aim of reducing vulnerabilities and developing the capaci-
ties of ecological systems to cope with floods through multi-
disciplinary approaches (Few, 2003; Schanze, 2006; Miceli
et al., 2008; Sayers et al., 2013). Non-structural measures
include flood risk mapping, land use zoning and planning,
flood vulnerability assessment, flood proofing, flood mod-
elling, institutionalization of policies, flood awareness cam-
Nat. Hazards Earth Syst. Sci., 16, 349–369, 2016
U. C. Nkwunonwo et al.: A critical review of Lagos urban flood risk management 357
paign, flood insurance, flood forecasting, relocation of prop-
erties, resettlement of human population, and green infras-
tructure planning (Merz et al., 2007; Jha et al., 2012; Smith,
2013). Fundamental to these measures is the assessment of
flood risk which is a procedure to estimate the damage or
negative impacts resulting from flooding. Flood negative im-
pacts are often classified in terms of tangible and intangible
damage. Tangible damage such as damage to properties and
infrastructure are those that can be associated with mone-
tary values. Intangible damage is difficult to express in mon-
etary terms and may include depression, anxiety, and loss of
life. Categorization of flooding impacts as direct and indi-
rect damage is also applicable. Direct damage includes those
which result from direct contact with flood water. When di-
rect flood damage is tangible, a broader classification, direct
tangible flood damage, applies. Indirect tangible flood dam-
age is a secondary consequence of direct flood impacts and
may include economic disruption, individual misfortune, and
an increase in water-borne diseases (Samuels et al., 2006;
Hammond et al., 2015).
The assessment of flood damage on the basis of damage ty-
pology is characterized by significant limitations. By means
of heterogeneous methodologies, assessment of direct tangi-
ble flood damage has received significant attention in the lit-
erature (Hammond et al., 2015; Samuels et al., 2006). Dam-
age functions, especially stage–damage curves which have
been applied in many case studies around the world, remain
potential tools for assessing direct and indirect tangible flood
damage (Smith, 1994; Merz et al., 2004). A major limita-
tion of stage–damage curves arises from the neglect of water
flow velocity which also influences flood damage. To date,
the difficulty in assessing intangible flood damage remains
unresolved. Methods are being proposed in the current lit-
erature, for example the concept of “anxiety–productivity–
income” which assumes that anxiety is a function of flood
water depth and duration (Lekuthai and Vongvisessomjai,
2001; Price and Vojinovic, 2008). The “Risk-to-life” model,
which uses flood characteristics and an estimate of the num-
ber of people exposed to flooding to assess the possible mor-
tality, was proposed by Jonkman et al. (2008). A compre-
hensive review of other current methods to assess intangible
flood losses can be found in Hammond et al. (2015).
Despite the progress made so far, uncertainties and the lack
of time series stage data and good-quality damage data are
major factors constraining the ubiquitous assessment of flood
risk. In line with predictions of worsened future risk scenar-
ios, these constraints underscore the importance of develop-
ing capacities for estimating flood hazard (in terms of wa-
ter depth, velocity, etc.), exposure, and vulnerabilities of el-
ements at risk as discrete components. The review presented
in this research considers various aspects of Lagos flood risk
assessment and management in light of the general context
of flood risk assessment. With regard to flood risk assess-
ment, procedures to estimate flood hazard are reviewed. Fun-
damental to the research is knowledge about the extent to
which current and future ecosystem exposure to flood hazard
have been influenced. Given reported trends in urbanization
and population growth (summarized in Sect. 8.1), it can be
assumed that exposure of systems to flooding in Lagos is at
a critical level.
6 The management and reduction of flood risk in
6.1 General measures
General measures to tackle the challenges of flooding in La-
gos have been discussed by Oshodi (2013). Recent practices
have included:
1. The expansion of drainage infrastructure within the city
2. The annual debris removal from principal drainage fa-
cilities within the city heartland.
3. Providing advice to the inhabitants of flood plains and
wetlands to relocate.
4. The demolition of homes in flood-prone areas.
5. Proposed resettlement scheme for the residents of Ogun
River catchment areas.
Oshodi (2013) claimed that these practices are being carried
out, although it could be argued that they are politically in-
fluenced. One example of this is the expansion and upgrad-
ing of the primary drainage facilities mainly being carried
out in Bariga, Surulere, and Gbagada. The annual clearing
of primary and secondary channels by Lagos State Govern-
ment through the Ministry of the Environment is carried out
principally in the metropolitan areas. Evacuation and reset-
tlement is carried out for residents who live in flood-prone
areas. A proposed resettlement scheme for residents of Aje-
gunle community near Ikorodu was undertaken between Oc-
tober 2011 and January 2012 (Oshodi, 2013). The move was
necessitated based on the belief that the current location of
the community in the Lagos urban Master Plan was origi-
nally zoned as wetland for agricultural use. The area was a
major catchment of Ogun River. It could be argued that the
lack of clear implementation policy for the plan with enor-
mous housing shortfall in the city to cope with rapid popu-
lation growth and urbanization has led to the conversion of
the area into residential use. Significant environmental im-
pacts are often associated with the use of land for purposes it
was not originally allotted for. Flooding can be the case when
such inappropriate use affects ecological equilibrium. How-
ever, a sound investigation is needed to validate this claim,
especially within the context of Lagos.
Major failures of these general measures arise from the
issues of continuity and the scope of application. These mea-
sures are often limited to the core urban areas of the city, ex-
cluding the majority of the outskirts (Oshodi, 2013). Many Nat. Hazards Earth Syst. Sci., 16, 349–369, 2016
358 U. C. Nkwunonwo et al.: A critical review of Lagos urban flood risk management
areas within Lagos did not benefit from the expansion of
drainage facilities; moreover, the project was not completed
because of a change in administration. These projects often
suffer when new governments abandon uncompleted projects
of their predecessors. This shows the potential for urban mis-
management and the degree of limitation in urban develop-
ment given that there are many abandoned projects while new
ones are being considered. There are occasional inconsisten-
cies in the annual cleaning of the channels. Sometimes this
operation is delayed, which allows debris to accumulate in
the channels. Coupled with careless attention to the channels
after cleaning, accumulation of debris has led to early col-
lapse of the channels. This causes potholes on motorways
and retention surfaces for water during flooding.
The problems of where to relocate to and the sparcity of
support for relocation are overwhelming. Given the vast dis-
tribution of flood-prone areas and the limited financial re-
sources to facilitate resettlement, the choice of which slum
locations to resettle is complicated. Communities which can-
not be resettled often face the risk of having individual homes
demolished. Examples of this include the Agege and Ije-
shatedo demolitions in August 2011 and that of Ijora-Badia
in 2010, 2012, and 2013. The demolition of homes is under-
standably a distressing measure to those affected. It could be
argued that a particularly controversial aspect is the failure
and neglect of the state government to provide any form of
alternative housing arrangements to those whose houses have
been demolished. There have been a few exceptional cases,
for example the Ijora-Badia (World Bank assisted) drainage
channels project, which necessitated the demolition and
burning of homes. Following a community-led protest the
affected families were awarded relocation assistance costs.
On the basis of these potential government inadequacies,
Ahonshi (2002), Kamunyori (2007), and Basinsksi (2009),
cited in Lawanson (2015), argued that the achievement of
government’s urban sustainability goals (which include gen-
eral flood management measures) in Lagos are often with-
out regard to the needs of the poor residents of the area. At
the same time, demolition and eviction frequently leads to
forced social disconnection amongst families, and compen-
sation and legal process on behalf of those affected can take
a significant amount of time to complete. This is in part an
aspect of social vulnerability which needs to be investigated
within the context of Lagos urban flooding. Under the cir-
cumstances of eviction and resettlement uncertainties, most
people occupying the flood-prone areas seem to ignore gov-
ernment’s flood risk mitigation proposals and flood warnings.
This influences large-scale impacts of urban flooding in La-
gos. However, despite numerous tensions, this issue has only
received limited attention in the literature and in governance.
6.2 Institutional efforts
One critical aspect of flood response is the institutional ef-
forts which have been undertaken by local authorities and
stakeholders. Odunuga (2008) recognized several flood pre-
ventive and curative initiatives ranging from community self-
assistance actions to World Bank assisted programmes. Re-
cently, key initiatives, which include the Drain Dock and The
Emergency Flood Abatement Gang (EFAG), were launched
by the government of Lagos state to improve current ef-
forts towards addressing the challenges of flooding. The min-
istries of Environment, Works, and Health as well as the
Lagos Metropolitan Development and Governance Project
(LMDGP) have a number of initiatives aimed at control-
ling flood hazard in the area, and these include shoreline
protection, low carbon emissions, the school advocacy pro-
gramme, and the climate change club. Lagos is also the first
region in Nigeria to carry out a detailed topographic map-
ping of the area with LiDAR (Light Detection and Rang-
ing) data acquisition and GIS-based analysis aimed at ad-
dressing the challenges of flooding. In addition to these ef-
forts, the Nigerian government and international community
have been active with measures to address the challenges
of flooding at various locations within the country includ-
ing the Lagos area (Olorunfemi, 2011; NIHSA, 2013). As
well as engineering works such as dams, bridges, and sus-
tainable urban drainage systems there has also been finan-
cial assistance to victims of flooding and this appears to be
a common practice. These are undertaken by the National
Emergency Management Agency (NEMA), the Nigeria Hy-
drological Services Agency (NIHSA), the Nigerian Meteo-
rological Agency (NIMET), and the National Environmental
Standards and Regulations Enforcement Agency (NESREA)
which in 2009 superseded the Federal Environmental Protec-
tion Agency (FEPA). It is not intended to discuss the struc-
ture, specific roles, and the unique position of these agen-
cies with regard to flood management in Lagos. These as-
pects have been comprehensively discussed by Obeta (2014).
However, it is important to mention that the activities of these
institutions with regards to disaster management are gener-
ally coordinated by NEMA.
Although detailed data are not available, a key point will
be highlighted in terms of the historical perspective of dis-
aster management institutions, to give clarity to a synthetic
description of the temporal evolution of flood awareness in
Lagos. The institutional framework in Nigeria can be traced
back more than four decades in history. The federal govern-
ment of Nigeria has since the first, second, and third Na-
tional Development Plans of 1962–1968, 1970–1974, and
1975–1980 initiated plans for the management of all disas-
ters including flooding. This was organized through the fed-
eral and state ministries of works. On the basis of flood-
ing and associated hazards, the primary aim of these ini-
tiatives was to create awareness among the citizenry and
to develop sound response strategies. This development has
evolved to the present time into what is now known as in-
stitutional approaches to managing disaster. Lately, the insti-
tutional framework has incorporated operations such as flood
warning through the NISHA, improving general flood aware-
Nat. Hazards Earth Syst. Sci., 16, 349–369, 2016
U. C. Nkwunonwo et al.: A critical review of Lagos urban flood risk management 359
ness through the National Orientation Agency (NOA), and
integration of local state and federal disaster emergency man-
agement agencies.
Despite the recent initiatives, these developments have
been criticised as weak, while the roles of the institutions
are not clearly defined (Adeaga et al., 2005; Oshodi, 2013;
Soneye, 2014; Nkwunonwo et al., 2014; Adelekan, 2015).
Critically, current measures undertaken by these agencies ap-
pear aimed to control flood rather than mitigate its impacts
on ecological systems. Efforts are being made to facilitate
evacuation and provide flood victims with urgent humani-
tarian needs. Environmental sustainability and policy, social
responses, physical intervention, and environmental manage-
ment are also critical issues requiring attention (Aderogba et
al., 2012; Olajuyigbe et al., 2012; Aderogba, 2012b; Adeaga,
2008, Ilesanmi, 2010). However, despite the increasing num-
ber of people affected, the effectiveness of these efforts is
challenged. Whilst it is unreasonable to claim that the weak-
ness of these flood mitigation measures probably leads to
more frequent flooding in the area, in can be argued that such
measures have improved the experience of the general popu-
lation with regard to flooding.
6.3 Recent research efforts
From the literature, researchers have suggested several op-
tions in relation to possible flood hazard mitigation and
adaption responses. Adedeji et al. (2012) highlighted the
importance of building the capacity for flood preparedness
through spatial planning and land management. Ogunsote et
al. (2011) suggested combating environmental degradation
through sustainable landscaping. The need for sustainable
management of solid waste which was emphasized in sec-
tion 3 of this paper was recommended by Folorunsho and
Awosika (2001). Komolafe et al. (2014) argued for the adop-
tion of proactive measures to risk management and adapta-
tion whilst constant geophysical and hydrological evaluation
of rising groundwater levels was emphasized by Oyedele et
al. (2009). Adelekan (2013) reiterated the UNISDR recom-
mendation which calls for the participation of the private sec-
tor in risk management through investment decision making
in building and construction. Other factors besides flood pre-
vention are also important to reduce the potential impacts of
flood events. The humanitarian relief supply chain for vic-
tims of flooding in the Lagos area was investigated by Son-
eye (2014). This study identified the need for more empiri-
cal investigation into such crucial components of flood risk
management in Lagos. In relation to the planning framework,
sustainable housing development and functionality of plan-
ning laws and regulations as well as the role of governance
in flood management in the Lagos area and indeed in Nige-
ria have been examined by a number of authors including
Aluko (2011) and Oshodi (2013).
As well as the general discussions in the literature, there
is other research which focuses on integral components of
flood risk such as probability of flooding, and exposure and
vulnerability to flooding. But these are insufficient, and leave
significant gaps in knowledge. Insufficient knowledge of the
vulnerabilities to flooding of local communities, urban resi-
dents, and the general public constrains effective flood risk
management in Lagos. Urban flooding in particular has ar-
guably not received the attention it deserves. A general cri-
tique, which should provide a nuanced understanding of the
strengths and limitations of present efforts to address the
threats of flooding in the Lagos area, is lacking. The lack of
flood data and other ancillary data, as discussed in Sects. 3
and 5, is a major setback towards containing these threats
and has not been fully addressed. Importantly, the focus of
these studies which solely rested on general knowledge of
the causes, impacts, and remedies of flooding suggests that
the global view of the situation has been imperfect. More
scientific approaches such as the flood modelling and flood
vulnerability assessment which drives recent approaches to
flood risk management in more developed countries are gen-
erally lacking. Little action has been undertaken to raise pub-
lic awareness of flood risk or to address gendered vulnera-
bility, as highlighted by Odunuga et al. (2012), Ajibade et
al. (2013), and Adelekan (2010). As an unprecedented mea-
sure, the Lagos state government has made significant efforts
at providing high-resolution air-borne LiDAR data and topo-
graphic maps which promote research towards flood risk in
the area. However, since many of these data sets are produced
and sold commercially, the limited access of researchers to
them arguably undermines their usefulness. A possible so-
lution to such a limited access to LiDAR data is to apply
global data sets such as ASTERGDEM (Advanced Space-
borne Thermal Emission and Reflection Radiometer Global
Digital Elevation Model) and STRM (Shuttle Radar Topo-
graphic Mission). However, the resolution of spatial data is a
crucial factor in flood modelling and flood risk assessment.
Due to the geomorphology of urban features which signif-
icantly influence hydrodynamics, global data sets often do
not provide realistic results when used to model flood hazard
in urban areas (van de Sande et al., 2012). Flood modelling
research is still looking into possible ways of simulating ac-
curate flood variables on the basis of low-scale global data
7 Flood risk assessment in Lagos
There has been a great deal of research about the assess-
ment of flood risk in Lagos in general. However, it can be
argued that none of these studies explicitly assessed the level
of exposure to flooding of social and environmental sys-
tems. This aspect of flood risk assessment can be derived
from studies that consider LU and LC change analyses, and
population expansion and urbanization (see Table 3). From
the literature, it is clear that vulnerability is being assessed
under varying contexts and objectives. No study known to Nat. Hazards Earth Syst. Sci., 16, 349–369, 2016
360 U. C. Nkwunonwo et al.: A critical review of Lagos urban flood risk management
the authors has considered flood hazard estimation, although
Odjugo (2006) and Adelekan (2010) investigated rainfall pat-
terns over spatial and temporal scales. Odjugo (2006) inves-
tigated the changing rainfall pattern in Lagos over 3 decades.
Adelekan (2010) on the basis of qualitative survey and sec-
ondary data analyses attributed increasing flood risks in La-
gos Island mainly to changes in the frequency and intensity
of rainstorms between 1971 and 2005. Other studies that es-
timate flood hazard were embodied within the general frame-
work of climate change research (see for example Aderogba,
2012a). The lack of an explicit study on flood hazard esti-
mation makes it difficult to appreciate how the probability
of flood hazard occurrence is being determined in Lagos.
Moreover, a clear understanding of the evolutionary trend of
the hazard is denied. A consensus view is that the hazard
has been increasing over the last 5 decades (Odunuga, 2008;
Adelekan, 2015). It is expected that future research should be
directed towards this crucial aspect of flood risk assessment.
7.1 Exposure
LU and LC analyses are procedures to classify land use/cover
and to identify rates and patterns of change. However, the
outcome of these analyses to Lagos has continuously sug-
gested expansion in the urban areas. LU and LC analyses
provides a basis for researchers and policy formulators to
analyse the current and future urban exposure to environmen-
tal hazards especially flooding. Flood risk is heavily influ-
enced by human and economic developments which evolve
within spatial and temporal scales (Samuels et al., 2006).
These developments are known to influence the hydrologi-
cal cycle particularly through the development of more im-
pervious surfaces which reduce soil infiltration capacity and
lead to increased surface water runoffs. The spatial and tem-
poral dimensions of flood risk can in part be directly related
to LU and LC modifications. Barredo and Engelen (2010)
and Gupta and Nair (2010) have shown that modelling LU
and LC scenarios is integral to flood risk management. Iden-
tification of the population and urban growth pattern is also
fundamental (Barredo and Demicheli, 2003). Many studies
covering this crucial aspect of flood risk assessment within
the context of the Lagos area exist in the literature (Table 3).
Some of the major conclusions emerging from these studies
show that significant sprawl and development in residential
and industrial or commercial land classes are progressively
taking place. There has been also been increasing pressure on
arable lands (Akpomrere and Nyorere, 2012) and depletion
of wetlands, mangroves, and swamps are significant issues
(Obiefuna et al., 2013). The associated migration of people
into Lagos city from other rural communities and states in
Nigeria escalates residential needs and challenges. Barredo
and Demicheli (2003) predicts that up to 27 million people
will inhabit Lagos by 2020. Based on these studies, it can be
shown that the level of human and economic resources ex-
posed to urban flooding in Lagos is undoubtedly high. Fig-
ure 6 shows the 2012 LU and LC of the Lagos metropolis of
Nigeria. Despite this, Lagos is relatively low on a global scale
when compared to Calcutta, Dhaka, and Miami (Nicholls et
al., 2007). However, the need to identify and address the vul-
nerabilities of exposed systems should be prioritized.
7.2 Vulnerability
There are numerous studies that have considered the vul-
nerabilities of social and environmental systems to flooding
within the Lagos context (for example, Action Aid, 2006;
Douglas et al., 2008; Adelekan, 2010; Ajibade et al., 2013,
2014; Nkwunonwo et al., 2015; Nsorfon, 2015; Olokesusi et
al., 2015). Action Aid (2006) investigated vulnerability but
tied Lagos with five other African cities. The study was car-
ried out on the basis of key management criteria including
local people’s perceptions of the causes of flooding, adap-
tation, and the community’s social coping capacity. Some
of the limitations in the study were addressed by Douglas
et al. (2008), who considered the vulnerability on the ba-
sis of climate change and adaptation strategies for the urban
poor in Africa. Adelekan (2010) investigated the vulnerabil-
ity of coastal communities in Lagos and responses to chang-
ing climatic conditions. The patterns of flood vulnerability
and resilience amongst women were investigated by Ajibade
et al. (2013). On the basis of political ecology, Ajibade et
al. (2014) argued that the two crucial factors responsible for
vulnerabilities of social systems in Lagos are limited ac-
cess to housing and weak housing rights. The sources of
social vulnerability to floods in informal settlements of La-
gos was investigated in Nsorfon (2015) while Nkwunonwo et
al. (2015) highlighted the relevance of assessing such vulner-
ability for the whole of Lagos. Olokesusi et al. (2015) inves-
tigated the influence of awareness of and responses to flood
warnings on physical vulnerabilities of the affected commu-
nities in Lagos.
Although these studies are major contributions to knowl-
edge which provide some evidence to suggest that vulner-
ability is an important issue of flood risk in Lagos, signifi-
cant gaps still exist in the literature with regard to accurate
assessment of vulnerability in the area. Most of these stud-
ies were based on a limited random sample of data which is
insufficient to make accurate generalization. Critical issues
of vulnerability analyses such as choice and measurement of
vulnerability indices were not addressed. This contradicts a
widely accepted philosophy that accurate assessment of vul-
nerability is related to these critical issues (Adger, 2006).
Classical analyses of vulnerability should be able to consider
every available factor that undermines the chances of resis-
tance available to social and environmental systems.
Nat. Hazards Earth Syst. Sci., 16, 349–369, 2016
U. C. Nkwunonwo et al.: A critical review of Lagos urban flood risk management 361
Table 3. Studies on exposure to urban flooding in the Lagos area of Nigeria.
S/No. Author(s) Study Context Major findings
1 Nwafor (1986) Physical environment, decision-making and
land use development in metropolitan Lagos Urban growth Rapid changes in land use classes were detected. Major upward trend in urban
growth since 1960. Urban renewal and highway development radiating from the
inner city to the hinterland were the major catalysts.
2 Abiodun (1997) The challenges of growth and development in
metropolitan Lagos. Urban growth Extensive and persistent urban growth. Key growth factors are the city’s eco-
nomic vitality and pivotal position in Nigeria’s economy. Major growth chal-
lenges are survival of urban residents and city’s sustainable development.
3 Barredo and Demicheli (2003) Urban sustainability in developing countries’
megacities: modelling and predicting future ur-
ban growth in Lagos.
Urban growth By 2020, Lagos will experience astronomical spatial growth as a direct conse-
quence of population expansion. Up to 27 million people will inhabit Lagos by
4 Adepoju et al. (2006) Land use/land cover change detection in
metropolitan Lagos (Nigeria): LU andLC change detection Lagos urban growth is phenomenal. Between 1984 and 2002, about 35 % in-
crease in urban areas was recorded
5 Sunday andAjewole (2006) Spatial determinants of urban land use change
in Lagos, Nigeria. LU and LC change detection Changing pattern of LU and LC in Lagos is characterized by significant socio-
economic and environmental implications. Flooding and other implications are
expected to worsen in the future given this present trend.
6 Braimoh and Onishi(2007) Implications of the changing pattern of LC of
the Lagos coastal area of Nigeria. LU and LC changedetection Remote sensing was used to investigate LU changes, while binary logistic re-
gression was used to model the probability of observing urban development as
a function of spatially explicit independent variables.
7 Odunuga (2008) Urban LU change and the flooding patterns in
Ashimowu Watershed, Lagos, Nigeria LUscenario and flooding (Alimosho) A progressive increase in built-up area at the rate of 28ha yr1between 1965
and 2003.
8 Olaleye et al. (2009) LU change detection and analysis using re-
motely sensed data in Lekki Peninsula area of
Lagos, Nigeria.
LU and LC change detection Between 1964 and 2003 built-up areas grew from 40.93 to 7271.19 ha. Evolu-
tion in new classes of LU was observed, which include industrial, commercial
and recreational LU class.
9 Nwokoro and Dekolo (2012) LU change and environmental sustainability:
the case of Lagos metropolis. LU change and environmental sustain-
ability Between 1990 and 2006, built-up areas increased by approximately 17 %. There
was an obvious loss of forest resources and agricultural land to urban develop-
10 Akpomrere and Nyorere (2012) LU patterns and economic development of Ikeja
in Lagos state, Nigeria: the GIS approach. LU patterns and economicdevelopment From 1962 to 1994, the built-up area in Lagos rose from 6.55 to 63.90 and from
63.90 to 67.99% between 1994 and 2004. Decreases in vegetation cover and
undeveloped areas were recorded.
11 Adebayo (2012) Impact of urban LU changes on property values
in metropolitan Lagos. Urban LU changesand property Significant changes in LU pattern from residential to commercial. Significant
implication in property values in the area. These created social and environ-
mental problems such as traffic congestion and noise pollution. The need for
adequate LU planning was identified.
12 Nkwunonwo (2013) LU/LC mapping of the Lagos metropolis of
Nigeria using 2012 SLC off Landsat ETM+
Satellite Images
LU and LC mapping By 2012, four major LU/LC themes were identified in Lagos: water body, veg-
etation, residential, and industrial areas. Urban areas, namely residential and
industrial areas, account for more than 54 % of the whole Lagos metropolis.
13 Obiefuna et al. (2013) Spatial changes in the wetlands of Lagos/Lekki
Lagoons of Lagos, Nigeria. Wetland changes Mangrove wetlands decreased from 88.51 to 19.95km2between 1984 and
2006 at 3.12km2yr1. Swamps decreased from 344.75 to 165.37 km2be-
tween 1984 and 2006 at 8.15km2yr1. Built-up areas increased from 48.97
to 282.78km2at 10.61 km2yr1. Water body decreased from 685.58 to
654.98km2at 0.16 km2yr1. Bare land increased from 24.32 to 72.73 km2at
2.2km2yr1. Vegetation decreased marginally from 1369.15 to 1361.08km2at
0.37km2yr1. Most of the increase in built-up area occurred in the Eti-Osa
Local Government Area (LGA) and then in the Kosofe LGA. The key implica-
tion is of flood risk on affected areas. Nat. Hazards Earth Syst. Sci., 16, 349–369, 2016
362 U. C. Nkwunonwo et al.: A critical review of Lagos urban flood risk management
Figure 6. 2012 Land use (LU) and Land Cover (LC) map of the Lagos metropolis of Nigeria. Source: Nkwunonwo (2013).
8 The case for flood modelling in Lagos
Based on the issues identified by this research with regard
to Lagos, three significant issues emerge which are: (1) lack
of data relating to flooding and its consequence, (2) lack of
accurate flood risk assessment, and (3) the “unidentifiable
method” of flood hazard estimation. To address these issues,
flood modelling which is widely being applied in hazard re-
search (see for example Samuels et al., 2006; Merz et al.,
2010) to estimate flood hazard should be considered. Atten-
tion should be given to the specific objectives that can be
achieved in Lagos. It is also important to relate these objec-
tives to specific factors which account for the reasons flood
modelling has been largely ignored in the area.
Whilst it is widely acknowledged that stage–damage func-
tions (presented in Sect. 5) are viable tools for flood risk as-
sessment (Samuels et al., 2006; Merz et al., 2010; Hammond
et al., 2015), the benefits which Lagos flood risk assessment
can derive from such a tool should be investigated. This de-
pends on the availability of various data relating to water
depth and extent of flooding events. Even the use of probabil-
ity concepts to estimate flood hazard requires data relating to
a large sample of historical flooding events. As these data are
not readily available for Lagos, a flood modelling approach
can be used to reconstruct particular historical events (such
as 1 in 50, 1 in 100, 1 in 200, 1 in 500, and 1 in 1000 flood re-
turn periods) in terms of inundation depth, extent, and water
flow velocity, and on the basis of simulated data predict fu-
ture occurrences. This will largely improve warning systems
currently in place. However, when flooding occurs, and a pre-
dicted return period is the case, field survey should be carried
out to determine properties and assets that are exposed. If the
present market values of the exposed elements are known,
damage functions on the basis of ex post flood hazard es-
timate can be used to assess the level of risk following the
flooding event.
Theoretically, flood modelling is a procedure to investigate
how rainfall or any other hydrological input into a drainage
area is transformed to a streamflow (Chow et al., 1988). Since
many of the floods in Lagos are pluvial based, accurate flood
modelling results will assist in delineating areas likely to get
increased runoff volumes and flooding. Flood modelling will
play an important role in producing Lagos flood hazard and
flood risk maps which do not currently exist. Needless to
say, a comprehensive flood risk and flood hazard map for La-
gos will increase public awareness of flood risks and inform
stakeholder decision about flood mitigation options and poli-
cies in terms of structural and/or non-structural measures.
From the point of view of cost benefit analysis (CBA), Lagos
area will derive maximum benefits in the long run if flood
modelling is the basis of any flood management operation.
Flood modelling is used to promote flood risk reduction
in the US, the Netherlands, and the United Kingdom, but in
Nigeria it is arguably too often ignored. This has continued
to raise the question of how actionable flood risk assessment
can be achieved. A number of structural measures are be-
Nat. Hazards Earth Syst. Sci., 16, 349–369, 2016
U. C. Nkwunonwo et al.: A critical review of Lagos urban flood risk management 363
ing put in place. However, an issue that has been less con-
sidered in the Nigerian context is the reliability of structural
measures in the absence of accurate flood data and scien-
tific means of acquiring such data. Flood modelling has been
largely ignored in Lagos for reasons such as data require-
ment and availability, lack of specialist technology, funding,
and the applied skills required. Academic research seems to
be the most likely option in terms of the responsibility to de-
velop flood models. The present research has been unable to
refer to specific contributions of academic research towards
flood modelling. However, the lack of bespoke or generalized
flood models and poor application in flood risk management
in the area seem to suggest that flood modelling procedures
considered by academic curricula in Lagos are mainly theo-
retical and on the periphery. As NIHSA (2013) pointed out,
such an intensive research should be funded by the govern-
ment and other interested bodies. To date, the researchers are
not aware of any such development. Moreover, the uncertain-
ties associated with flood modelling can discourage invest-
ment of resources into it. To the best of the authors’ knowl-
edge, no public agency in Lagos undertakes the procedure as
a specific role.
It can be argued that relatively few studies have high-
lighted the relevance of flood modelling and its implications
with the paucity of topographic data (Nkwunonwo et al.,
2014; van de Sande et al., 2012), although Adeaga (2008)
implemented a flood hazard mapping and risk management
in the northeastern part of Lagos. Although flood modelling
was mentioned in these studies, solutions to the problems
raised remain largely unanswered. Critically, current mea-
sures undertaken by flood management agencies appear to
control flood rather than mitigate its impacts on human pop-
ulations and urban infrastructure.
9 Flooding in Lagos – the way forward
The review of flood management covered in this research
prompts several recommendations for reducing flood risk in
Lagos. These recommendations are based on three key con-
siderations: first, is the understanding and demonstration of
the roles more scientific approaches (such as flood mod-
elling,) can play in flood risk reduction within the context
of Lagos; second, is the need to align the focus of flood
risk reduction in the Lagos area to the objectives of simi-
lar measures in more developed countries such as the US,
the UK, and the Netherlands. This should be linked to im-
proving collaboration between Lagos and indeed Nigeria and
the developed countries in terms of promoting a more effec-
tive flood risk management philosophy. In hazard research,
the need for collaboration to strengthen learning and infor-
mation exchange is increasingly being identified (Thomalla
et al., 2006). Moreover, similar to the European Union flood
risk directive, regional collaborations are being advocated for
countries in Africa (Holloway, 2003). Thirdly, there is a need
to promote awareness of flooding among local communities,
urban residents and the general public and to delineate more
suitable locations for relocation of human populations during
flooding events.
Further specific recommendations include:
1. The government of Lagos state should as a matter of ur-
gency prioritize legislation and provision of resources
towards flood hazard and flood risk mapping for the
whole of Lagos state. This is the basis of flood risk mit-
igation within the European Union framework, which
requires all constituting states to prepare flood hazard
and flood risk maps to promote the concept of living
with floods (EC, 2004).
2. Flood risk reduction under the “living with floods” idea
is multi-disciplinary, indicating that various industries
can assist in reducing the impacts of flooding. This is
the case in the UK in particular (EA, 2010). In view of
the widening of public awareness of flooding, there is
a need for improved collaboration between the Lagos
state government and federal ministries, departments,
and agencies such as NEMA, NESREA, and NIHSA.
3. Flood alert and flood early warning systems should
be improved within the Lagos area. Globally, there
is a growing concern regarding the dissemination of
and response to flood warnings (Moore et al., 2005;
Parker et al., 2009). On the basis of this, researchers in
the UK and other European countries are anxious that
flood warning systems are failing to yield the expected
scale of damage savings (Penning-Rowsell et al., 2000;
Parker et al., 2009). A review of 20 years of the progress
of hazard warning systems in the US was presented by
Sorensen (2000) although this research shows that no
warning system is perfect for any hazard.
4. A series of issues need to be addressed with regard to
the design of flood warning systems, and improved fore-
casting and response systems which correspond to the
needs of the public and are often influenced by social,
economic, and environmental variability. These issues
should underlie improvements in any flood warning sys-
tems in Lagos. The cultural, social, and religious values
of the people (which are important to many residents
of Lagos) may also need to be taken into consideration
when disseminating flood warnings. The reluctance of
many people living in flood-prone areas to heed flood
warnings should also be thoroughly investigated.
5. Flood insurance is a non-structural approach which
many property owners have benefitted from in devel-
oped countries following flood disasters. It is argued
that the benefits of flood insurance far outweigh the lim-
itations which exist (Treby et al., 2006; Crichton, 2008).
Flood insurance is still being applied in places like the Nat. Hazards Earth Syst. Sci., 16, 349–369, 2016
364 U. C. Nkwunonwo et al.: A critical review of Lagos urban flood risk management
UK, the Netherlands, and Indonesia, although the cov-
erage is at a relatively low scale (Jha et al., 2012). The
need to enable flood victims to recover more quickly
underscores flood insurance (Lamond and Penning-
Rowsell, 2014). Purchase of insurance is highly depen-
dent on a number of factors, including its availability
and cost, the level of the provision of disaster relief, gen-
eral risk awareness, and attitudes to collective and indi-
vidual risk (Lamond et al., 2009). For the Lagos area,
poor awareness of flood insurance is a major issue. Ur-
ban residents need to know that a means of assisting
them recover from flood losses is possible. They must
be given the opportunity to try flood insurance based on
individual volition. To support the roles of flood insur-
ance in Lagos, it is recommended that the role of FEMA
in this regard should be extended to the state, whilst en-
couraging insurance companies to commence an aware-
ness campaign for property owners to take positive steps
towards purchasing insurance cover.
6. The enforcement of environmental standards and laws
is often a key factor towards containing adverse effects
of climate change including flooding (UN/ISDR, 2004).
Indiscriminate waste disposal, construction along the
flood plain, and the blockage of drainage facilities,
among other anthropogenic activities influence flood-
ing in Lagos and are often illegal. It can be argued that
NESREA should embark on enforcement measures to
address these issues.
7. The reaction to the 1953 floods in the Netherlands has
arguably made the Dutch an exemplar in terms of flood
management (Vis et al., 2003). Invariably, the success
of flood risk reduction in the Netherlands is built on a
strong commitment to avoid a repeat occurrence. The
population in general and the Dutch government are
committed to the collective efforts which underlie suc-
cess towards addressing the challenges of flooding. Col-
lective flood management costs each Dutch adult about
USD 110 annually (Kazmierczak and Carter, 2010). For
this reason, we recommend that urban residents and
the general public in Lagos need to engage more fully
in flood management and control. This would include
raising awareness of the risks and educating the wider
public about potential solutions. This would include en-
couraging adherence to environmental laws and a com-
mitment to engage with flood alerts and early warning
systems. To support this, more education is required to
make the public more aware about flooding and its con-
sequences. Qualitative research such as CBA, involving
the local community should also be encouraged.
8. Globally, it appears that research is proportional to suc-
cess towards addressing the threats of flooding. From
scoping investigations it is clear that literature relating
to flooding in Lagos appears embryonic compared to
literature in the US, the Netherlands, China, and the
UK for example. This is a strong indicator that more
research is required for Lagos. Equally, the universi-
ties and research agencies should be encouraged to in-
clude flood awareness and management in their curric-
ula and programmes. More research should be directed
towards developing bespoke hydrologic and hydraulic
flood models for simulating flood hazard and other hy-
drological parameters in the area.
9. Globally, accurate data play a key role in flood risk mit-
igation and the government of Lagos state has made an
unprecedented attempt to improve its data by the acqui-
sition of LiDAR data sets, although access to these data
sets has been limited due to funds. Given the importance
of these data sets and the need to optimize their use-
fulness for the Lagos area, the state government should
consider subsidizing these data sets for universities and
research institutions. Additionally, we also recommend
further improvement on data acquisition such as SAR
(Synthetic Aperture Radar) for flood modelling within
the Lagos area. It is argued that the key to wider ap-
plied research requires easy access to data and a collab-
orative approach between researchers and government
10 Conclusion
Flooding is a global phenomenon, but the impacts in many
urban areas in the developing countries can be overwhelm-
ing. It is easier to understand the threats of flooding in La-
gos by the attention generated both in the media and in aca-
demic literature relating to social and environmental science.
Flood waters have impacted upon the local population, de-
stroyed critical infrastructure, and disrupted economic activ-
ities. However, based on “current practice” in flood manage-
ment and flood risk reduction in the context of “living with
floods”, the actions of the state government and other stake-
holders towards addressing the challenge of flooding in the
Lagos area have arguably been limited. Unfortunately, rel-
evant data on flood events are not readily available and the
means of building a community resilient to flood threats have
continued to elude present efforts.
This research is an attempt towards addressing the chal-
lenges of flooding in and around Lagos. Looking to the fu-
ture, this research argues that flood modelling and assess-
ment of vulnerability are necessary requisites for more ef-
fective results towards addressing the challenges of flooding
in the Lagos area and indeed in Nigeria. The wider avail-
ability of high-quality data sets (including surface modelling
and detailed demographic data) is a crucial step towards ad-
dressing this problem. It is recognized that a major limitation
of this study and many other studies is the level of infor-
mation available with regard to flooding in the Lagos area.
The majority of the research offers a generalized overview
Nat. Hazards Earth Syst. Sci., 16, 349–369, 2016
U. C. Nkwunonwo et al.: A critical review of Lagos urban flood risk management 365
of flooding rather than scaling the hazard to the local level.
If flood data had been available for LGAs, it would have
offered a better understanding of the spatial distribution of
flooding over the epoch considered. In addition, there are
places within various LGAs which may never have flooded
over the period considered. It is important to investigate these
locations with a view to finding out how they defend them-
selves from flooding. It was not intended within this study to
address flood modelling and vulnerability assessment. How-
ever, the authors recommend future research that focuses on
developing bespoke flood models for simulating flood hazard
in the Lagos area of Nigeria.
Flooding is and will continue to be a hazard for the people
of Lagos. The key to ameliorating the effects of flooding on
the population is a more integrated, informed flood manage-
ment philosophy which is linked to improved data collection
and provision. This alongside greater public engagement and
education as well as improved government coordination will
greatly reduce the potential impacts of flood events on the
population of Lagos.
Author contributions. This work was carried out in collaboration
between all authors. Nkwunonwo Ugonna designed the study, per-
formed the statistical analysis, managed literature searches, wrote
the protocol, and wrote the first draft of the paper. Malcolm Whit-
worth and Brian Baily reviewed the first draft and made academic
contributions. All authors read and approved the final paper.
Acknowledgements. This publication derives from a PhD research
which is being funded by the Tertiary Institutions Education Trust
Fund (TETFund) programme for staff of university of Nigeria. The
Surveyors Council of Nigeria (SURCON) is acknowledged for
providing some emergency grants. Data relating to flooding were
sourced mainly from the Center for Research in Epidemiology
of Disasters (CRED), Nigeria’s Ministry of the Environment and
the Nigeria Environmental Study Action/Team (NEST). Previous
works in this area are equally acknowledged and so are the
anonymous reviewers of this paper.
Edited by: P. Tarolli
Reviewed by: three anonymous referees
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... Apart from these factors, studies also show that poor perception about flooding among the local communities, poorquality construction materials and non-adherence to flood warning, cultural/ ethnic affinity, and weak institutional framework contributes to the menace of flooding (Ayoade and Akintola 1980;Oriola 2000;Odunuga et al. 2012;Nkwunonwo 2013, Nkwunonwo et al. 2016Unaegbu and Baker 2014;Hula and Udoh 2015;Ibrahim and Abdullahi 2016;Oladokun and Proverbs 2016;Olanrewaju et al. 2019). The devastating impacts of flooding are enormous. ...
... Regarding flood management approaches, various countries have adopted different flood mitigation strategies such as channelization, natural and artificial barriers against water surges (Few 2003;Schanze 2006;Miceli et al. 2008;Sayers et al. 2013 andAdelekan 2016). The non-structural measures include flood risk mapping, land use zoning and planning, flood vulnerability assessment, floodproofing, and flood (Nkwunonwo et al. 2016). Other non-structural measures that have proven very effective in flood mitigation include institutionalization of policies, flood awareness campaign, flood insurance, community-based adaptation strategies at the grassroots, early warning flood forecasting, relocation of properties, resettlement of human population, and green infrastructure planning (Price and Vojinovic 2008;Merz et al. 2010;Jha et al. 2012;Smith 2013;Dhiman et al. 2019). ...
... A major environmental challenge in the region is fluvial flooding due to the low-lying nature of the state (Odunuga et al. 2012;Kaoje and Ishiaku 2017). The minimum ground elevation in the study area is about 6 m (approximately 20ft) above sea level around Surulere, while the highest point is at Ifako-Ijaiye, measuring about 80 m (approximately 260ft) (Nkwunonwo et al. 2016). According to NPC (2006), the area's population is estimated at 3,057,956, with an approximate density of 140,566/km 2 . ...
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Human vulnerability to disasters poses a significant concern to water resources management. The present study examined the factors influencing the occurrence of flooding, risk and management strategies in Lagos, Nigeria. A set of questionnaires was administered to 400 respondents in four randomly selected settlements in Lagos State based on perception and observation methods. Descriptive and multivariate statistics and cartographic mapping techniques were employed for data analysis. The result indicates that the majority of the respondents live in a rented room and parlor. The significant flood risks include poor sanitation, a breeding site for mosquitoes, water contamination/waterborne diseases, and mental stress. Factors analysis explains 74.62% of the variance, indicating anthropogenic, natural, and institutional factors influencing flooding in the study area. The dominant flood management measures are clearance of drains, environmental sanitation, public awareness, training/education, while the significant steps taken by the government to ameliorate flooding challenges in the area include awareness, early warning, and education. The study concluded that there exists a significant difference in the factors influencing flooding across the settlements based on the ANOVA result given as: (DWSD F = 19.661, p < 0.05; RI = 41.104, p < 0.05; WIC = 18.123, p < 0.05; HWL = 37.481, p < 0.05; SD = 10.294, p < 0.05). The study contributes to knowledge using cartographic techniques to map the risks of flooding for easy understanding. The study has potential policy implications for planning and interventions in areas vulnerable areas. The study recommended monitoring of construction activities, enforcement of building codes, awareness campaigns, and early warning flood technology for sustainable flood management in the area.
... In Nigeria, several records of flooding occurrences and the corresponding effects/costs were reported from different parts of the country. For instance, cities such as Lagos [10][11][12][13], Ibadan [14,15], Awka and Onitsha in Anambra State [16], Port Harcourt [17,18], Benin [19], Ilorin [20,21], Kaduna [22], Akure [23][24][25] etc. recorded several devastating flood occurrences with loss of live and properties worth billions US dollars. In 2001 alone, not less than 5000 human lives were reportedly lost in various part of the country as a result of flood [26]. ...
... Most of the efforts yielded no positive and expected result as the occurrence keeps on un-abating thus rendering most of the inhabitants along the flood plains helpless. This suggests that more comprehensive flood risk studies are required for future flood control and risk reduction [13]. One of the crucial elements in the analysis of flood risk for future flood disaster and risk reduction is the exposures, which are the potential elements (tangible and intangible) that can be affected during a flood event. ...
Flooding is a serious problem affecting the urban environment and threatens the lives and properties of the urban settlers, including Akure, Ondo State in Southwestern Nigeria where it has become recurrent. The study assessed the impact of flooding on some elements at risk along Ala River in Akure, Ondo State, Nigeria using Remote Sensing and GIS techniques. The land use/land cover change detection of Ala River catchments was carried out using 1984, 2000 and 2015 Landsat images. Each of the classes and the positional accuracy of the river were validated using GPS (Garmin78SC). Buffers were generated around the river channels using high resolution Google Images as input data. The result of LULC showed that there was positive increase in built up land use from 17.65% in 1984 to 24.96% in 2000 and 65.67% in 2015. The results of buffering analysis showed that 105, 214 and 554 buildings with the estimated population of 2520, 5136 and 13,296, fall within 10 m, 20 m and 30 m distance to the river. The study concluded that the incessant occurrence of flood in the study area was as a result of some driving forces such as climate, rapid urbanization, terrain configuration and violation of building regulations that rendered most properties along the flood plain very risky.
... Additionally, Ref. [18], among others (see [59]), opine that the lack of reliable country-specific data and/or in-depth evidenced research relating to commercial buildings has contributed to this. This was an issue that several Nigerian studies identified as emblematic in the country as relates to sustainability [60,61]. Interestingly, available studies relating to office buildings reveal a predisposition toward quantitative research strategies, which [62] note reflects the culture of construction management research. ...
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The adoption and integration of renewable energy technologies (RETs) into buildings is key to making the necessary transition to low-carbon and resilient built environments. However, such technologies have struggled to gain a firm foothold in countries within the sub-Saharan African (SSA) region. This is particularly the case in Nigeria, which suffers from severe energy poverty, despite its significant RE and conventional energy potential. In Nigeria, a significant proportion of the energy demand for offices is provided by self-powered off-grid fossil-fuel generators. The country is also one of the primary settings for increased construction activity. This, combined with its susceptibility to the effects of climate change, presents significant concerns relating to the resilience of its built environment. However, there has not yet been a comprehensive empirical study addressing this, as previous studies have been limited in their insight and perspectives. This study adopted a grounded theory method (GTM) aligned with Charmaz’s approach, to gain in-depth participant-driven insights into factors influencing sustainable energy use in commercial buildings, focusing on solar photovoltaics (PVs). This led to the development of a theory of the sustainability transition process of construction professionals (CPs). It provides relevant, reliable, and relatable points of reference that would be beneficial to policymakers in developing plans for actionable interventions for PV and broader sustainable measures toward green energy transition. Furthermore, it highlights the value of employing GTMs in construction management research beyond the developing context. This paper contributes theoretically, empirically, and methodologically to facilitate a better understanding of the situations (context) grounded in empirical data.
... There has been an increasing impacts of flooding events in Lagos state Nigeria. According to Nkwunonwo [14], a severe occurrence of flooding event of July 2011 affected approximately 5000 individuals (both dependent and working-age group) while 25 deaths were recorded due to the flood event. Public infrastructure such as bridges, schools and road networks, as well as residential houses were all inundated and destroyed by floodwater [15,16]. ...
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Flooding is one of the natural hazards affecting various parts of Nigeria, causing loss of life, impeding health, and disrupting human livelihood. This paper seeks to address the flooding issue by using geospatial analysis to model flood susceptibility in Amuwo Odofin Local Government Area of Lagos State. A multi-criteria method was adopted, using parameters such as rainfall, distance from rivers and streams, land use and slope. The flood susceptibility map produced from the analysis indicates the fourlevels of risk to flooding (very high, high, low, and very low-risk levels) at different locations of the study area. The findings revealed that Amuwo Odofin covers about 171.19 sq km, 10 percent of which fall within the very high-risk zone, while the high-risk zone covers 50 percent of the total area. The final map shows that locations nearer to the water bodies and within low terrains are susceptible to flooding. The communities within the very high and high-risk zones include; Iyagbe, Ibese, Isunba, Irede, Kirikiri, Aiyetoto- Asogun, Elachi, Isuba, Olute, Satellite town, Alapako, Amuwo, Agboju. Communities at lowrisk zones include Ijegun, Iseri- Osun, Ijagemo. Notably, roads and buildings will be flooded if the right actions are not taken on time. These findings are vital for appropriate government agencies such as town planners, civil society, emergency management agencies and other key stakeholders who can implement preparedness, evacuation planning, and early warning to settlements within the inferred flood risk zones.
... The replenishment of the surface/sub-surface water demands as well as its abundance leading to surface accumulation is significantly related to the rainfall received. Besides the amount of rainfall and its intensity, the local physiography and urban structures exert a definite influence on the nature and magnitude of surficial flow of rain water in the city and its surroundings (Pappas et al. 2007;Tingsanchali 2012;Nkwunonwo et al. 2016;McGrane 2016;Bhattacharjee et al. 2021). ...
The book discusses a number of environmental and development issues in developing countries. The book consists of 27 chapters, dealing with various environmental issues that concern biological diversity and climate change in developing countries. The book is edited by Prof. Narayan Chandra Jana and R. B. Singh Editors More about book
... The replenishment of the surface/sub-surface water demands as well as its abundance leading to surface accumulation is significantly related to the rainfall received. Besides the amount of rainfall and its intensity, the local physiography and urban structures exert a definite influence on the nature and magnitude of surficial flow of rain water in the city and its surroundings (Pappas et al. 2007;Tingsanchali 2012;Nkwunonwo et al. 2016;McGrane 2016;Bhattacharjee et al. 2021). ...
Full-text available
This study aimed to monitor the degradation of biodiversity in one of the southwestern region of Saudi Arabia. The study area has a rich diversity of flora and fauna, particularly in juniper trees ecosystem. The total area covered with natural vegetation cover was 4385.6 km2 in 1980; it decreased to 3645.5 km2 according to the satellite image of 2019. Population growth and urban sprawl were the main factors causing the degradation of natural vegetation cover in this region.
... Nigeria's flooding is mainly rainfall-induced and compounded by a host of anthropogenic factors tied to poor governance (Agbola et al. 2012;Odufuwa, Adedeji, and Oladesu 2012). At the same time, evidence suggests the flooding in Nigeria can be effectively averted or controlled by putting in place and implementing a suitable integrated flood risk-management strategy (Adelekan 2016;Nkwunonwo, Whitworth, and Baily 2016). Figure 5 highlights the areas of Nigeria prone to flooding. ...
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Disasters annually ravage numerous African countries. Flooding is the most severe and prevalent adverse event and has serious implications for sustainable development. As the world is currently facing the COVID-19 pandemic, disasters such as flooding are still occurring but limited attention is being paid. This research analyzes the cause of flooding in Nigeria and Ghana, two countries regularly affected by floods. Previous analysis of the causes of flooding has mainly been done on a national scale. This work adopts a transnational approach by studying the flooding phenomena in both countries. It highlights an opportunity for international partnership in disaster-risk reduction (DRR) as both Nigeria and Ghana are signatories to the Sendai Framework for Disaster Risk Reduction that advocates an understanding of disaster risk and aims to foster international cooperation. Appreciating the root causes of flooding is the first step in building awareness of the common problem that could be the foundation of seeking and adopting solutions. A systematic review of peer-reviewed papers was conducted. This study finds that the underlying drivers of flooding are similar in the two nations and advocates research and data-sharing as ways of partnering to tackle the common problem. This finding has the potential to promote and facilitate capacity building for DRR and flood-risk management (FRM). Potential solutions could also be scaled to other countries of comparable profiles facing related flooding challenges. This approach is likely to yield better and quicker results while presenting opportunities for partnership in achieving the United Nations 2030 Agenda for Sustainable Development that has already suffered COVID-19-related setbacks.
Rapid growth of Guwahati, the largest urban center in India’s north-east, in terms of area, population, and functionality, is contributing to the complexity of the urban environment. Although due to the influence of monsoon the amount of rainfall in the city almost remains same, it has undergone distributional change, with decrease in rainy days and increase in high intensity rain events. Variety of factors typical to the dynamic environment of Guwahati characterized by surrounding hills, Brahmaputra flowing through it, the ever-expanding concrete surface, and high-rise buildings amidst somewhat rugged terrain across the city; induces severe urban flooding problems. The gravity of the situation can be marked by the fact that, moderate to heavy rainfall for about 2–3 h often results in high intensity urban flooding during the monsoon season. It has become a recurring problem which even transcends to be devastative in certain localities within the city and the life and living of the city dwellers become deplorable. Therefore, this study attempts to analyze the flooding pattern in Guwahati with respect to its intensity, identify the major causes and consequences associated with it, and understand the human response to deal with the resulting situation; primarily on the basis of field observation and investigations.
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Dance is a major form of bodily expression among communities and age grades and any society without dance could be dangerous for human habitation. It is from this perspective that this article appraises the symbols in the dances of the Anioma people of Delta State, Nigeria (Aguba of Ubulu-uku, Egwu Otta of Asaba, Okanga of Ibusa, Egwu Amala of Ndokwa and Ile Wonder of Umunede) to highlight their significance to the wellbeing of the people. The intention is to embark on an ethnographic journey into the semiotics and imageries of selected Anioma dances which in turn can be traced to the history of the communities they are located. The interviews and surveys will, hopefully, help to clarify some grey areas for researchers and traditional dance enthusiasts. The historical and sociological approaches of the qualitative method of research were employed in carrying out the study. Keywords: Semiotics, Indigenous Anioma dances, Images and symbols, Communication art Introduction The diversity in Nigerian dances
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With the ongoing controversies surrounding the purported removal of oil subsidy due to the deregulation of the downstream oil sector by the President Buhari’s regime, there is urgent need to revisit the issues the petroleum industry bill (PIB). Although the PIB has been described as ‘the most comprehensive piece of legislation in the history of the Nigerian oil and gas industry’; there are many provisions in it many interests don’t really appreciate. This has led to a serious controversy over the bill. For example, foreign oil companies and even foreign nations see it as an unwelcome intrusion into their traditional monopoly over the industry and an assault on their stranglehold over production and profits. The NNPC also perceives it as an effort to force it to be more open and transparent, a virtual death sentence for an institution which thrives on lack of openness and accountability. Northern legislators on their own see it as further enriching a zone which already takes more than it is entitled to, and impoverishing their region. South-South legislators think it makes too little provision for more. Federal government thinks the legislation is poorly understood by Nigerians, and has become unduly politicised. It has become obvious that, there is a need for stakeholders to really find a middle ground at resolving the nagging controversies stalling the passage of the PIB. It is within this context that this article reviews and critically considers the Nigerian oil industry before PIB; reflects on the history of legislation in the oil sector; highlights the basic provisions of the PIB; brings out its possible impact on the deregulation of oil sector; examines the controversies surrounding the bill and its purported benefits to the Nigerian people and the economy; and suggests some ways out of the quagmire to ensure the passage of the bill for the greater good of the Nigerian nation. Keywords: Nigerian economy, PIB, Foreign oil companies, NNPC, Poverty. NB: This article was published few days before the passage of the Petroleum Industry Act (which emanated from the Petroleum Industry Bill by the President Buhari's Government in Nigeria after 14 years of delay
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Apart from traffic congestion, flood is the most common serious physical urban problem in most Nigerian cities. This usually results from high river levels, concentration of overland flow following heavy rainfall, limited capacity of drainage systems and blockage of waterways and drainage channels. This study identified the factors responsible for perennial flooding in Mile 12 area of Lagos, Nigeria which has constituted serious menace in terms of socio-economic and environmental consequences. The research methodology involved questionnaire administration on households, key informant interview especially on Lagos State Physical Development Authority (LASPPDA) officials and participant-observation, while other data were collected from secondary sources including various relevant publications and text books. The result shows that the perennial flooding problem in Mile 12 is as a result of consistent high rainfall and water releases from Oyan dam in the neighbouring state of Ogun, Nigeria. Other causes of flood in the study area include blockage of drainage channels by refuse and other wastes, narrow river channels and construction along floodplain. In a bid to ameliorate the seemingly intractable problem of flooding in the study area, the recommendations made include: provision of sufficient setback to streams and rivers, construction of roads with good drainage system, channelization and building of more dams to avoid excess loading of the existing dam.
Extreme weather events have caused havoc to lives and properties in recent years. Research and development have also been focused on these global phenomena. The situation is getting alarmed in Nigeria. The aim of the paper is to study incidences of floods in Nigerian cities and towns. Topographical Maps of 25 cities and towns were studied. Floods, drainage channels, runoffs and effects of human activities on floods were observed and studied. Interviews were conducted with 20 professionals, urban dwellers and twenty Local Government Chairmen of the cities and towns. There was a questionnaire that was administered among 2,000 urbanites. It collected data about the frequency, sizes and havocs caused by floods. Some of the cities particularly Lagos, Warri and Port-Harcourt are under the sea level with average gradient of less than 1:100,000. Run-offs are increasing in volume and areas of coverage but relatively drainage channels are inadequate; and they have been blocked through the adverse living habits of the urban dwellers. Waste waters are contributing as base water to rain water in the drainage channels. These result in grievous consequences of flood. All forms of transportation are affected each time it comes; lives, farm lands and properties are lost; and economic activities are grounded. Human factors are predominantly the cause. More attention has to be paid to urban physical planning.
This paper reviews research traditions of vulnerability to environmental change and the challenges for present vulnerability research in integrating with the domains of resilience and adaptation. Vulnerability is the state of susceptibility to harm from exposure to stresses associated with environmental and social change and from the absence of capacity to adapt. Antecedent traditions include theories of vulnerability as entitlement failure and theories of hazard. Each of these areas has contributed to present formulations of vulnerability to environmental change as a characteristic of social-ecological systems linked to resilience. Research on vulnerability to the impacts of climate change spans all the antecedent and successor traditions. The challenges for vulnerability research are to develop robust and credible measures, to incorporate diverse methods that include perceptions of risk and vulnerability, and to incorporate governance research on the mechanisms that mediate vulnerability and promote adaptive action and resilience. These challenges are common to the domains of vulnerability, adaptation and resilience and form common ground for consilience and integration.
Change in any form and in any society is inevitable; it has become part of an urban growth. For economic reasons, land and buildings will continue to change in use from a lower order to a higher order status in order to attain optimal use. Such changes usually result into land being allocated to its highest and best use culminating in higher economic returns. This study takes a close look at the impact of land use changes on property values in metropolitan Lagos with a particular reference to Victoria Island. One hundred questionnaires were administered to randomly selected estate surveyors, estate agents and managing agents practising on the island. The data obtained are analysed with the use of simple descriptive statistics, particularly frequencies, percentages and ratios. Findings show that there have been remarkable changes in land use pattern from residential to commercial and this had led to corresponding changes in property values in the area. Moreover, the changes in use have also created problems such as traffic congestion, over stretching of infrastructural facilities and noise pollution. There is therefore, the need for adequate land use planning to take care of the changes brought about by increased commercial activities. In addition, there is a need for town planning authorities to monitor the process of changes to prevent negative effect on the environment.
This paper examines the land use/land cover changes that have taken place in Lagos for the last two decades due to the rapid urbanisation. Lagos is one of the fastest growing mega-cities in the world; yet it lacks reliable modern, scientific monitoring techniques to effectively monitor and manage the land use changes brought about by urbanization. The capabilities of remote sensing in terms of large spatial coverage, spatial and temporal resolutions adequate for these type of studies as well as the ability of GIS to handle spatial and non-spatial data are the optimal approach for this. A post-classification approach was adopted with a maximum likelihood classifier algorithm. The Landsat TM (1984) and Landsat ETM (2000) were merged with SPOT-PAN (2002) to improve classification accuracies and provided more accurate maps for land use/cover change and analysis. It also made it possible to overcome the problem of spectral confusion between some urban land use classes. The land cover change map revealed that forest, low density residential and agricultural land uses are most threatened: most land allocated for these uses have been legally or illegally converted to other land uses within and outside the metropolis.