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Habitat International 38 (2013) 207e213

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Habitat International

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Colonization and sanitation in urban Africa: A logistics analysis of the availabilityof central sewerage systems as a function of colonialism

Ambe J. Njoh*,1

Urban & Regional Planning, Department of Geography, Environment and Planning, University of South Florida, 4202 E. Fowler Avenue, Tampa FL 33620, USA

Keywords:African citiesColonialismPublic infrastructureSanitationSewerage systems

* Tel.: þ1 813 974 7459; fax: þ1 813 974 4808.E-mail addresses: njoh@mail.usf.edu, njoh@usf.edu

1 Ambe J. Njoh is the author of nine books, includinAfrica (Ashgate, 2003), Tradition, Culture and Deve2006), Planning Power (UCL/Routledge, 2007), UrbanAfrica (forthcoming, Ashgate) and more than fifty pe

0197-3975/$ e see front matter � 2012 Published byhttp://dx.doi.org/10.1016/j.habitatint.2012.07.001

a b s t r a c t

The stock of public infrastructure inherited from the colonial era constitutes a strong predictor of thedevelopment profiles of African countries. The question that remains to be adequately addressed relatesto factors that determine the presence or absence of such infrastructure in the first place. The studyreported here employed a logistic analysis in an attempt to answer this question. Colonialism, oper-ationalized in terms of duration of colonial experience, government share of real GDP per capita, andcolonizer identity, is posited as a valid predictor of the availability of sanitation infrastructure. Thehypothesis is supported by empirical evidence. It is shown that, the availability of central seweragesystems in cities within any African country depends on how long the country was colonized. Colonizeridentity, operationalized in terms of the nationality of a colonial power, however, proved to have nopredictive ability.

� 2012 Published by Elsevier Ltd.

Introduction

One of the most nagging problems facing urban planners andmanagers in Africa relates to sanitation, especially the disposal ofhousehold wastes. Most households with access to improvedsanitation systems depend on the septic-tank-based system forhuman waste disposal. The system was introduced in Africa bycolonial authorities in the late-1800s. It consists of individual septictanks and absorption pits or holding tanks located on every lotcontaining buildings fitted with modern sanitary facilities. Thissystemworked well during, and immediately following the demiseof, colonialism. At that time, African urban densities were low.However, the system’s utility has been drastically reduced in thecontext of Africa’s contemporary proliferating and densely packedurban centres.

The flaws and risks associated with septic tanks are heightenedin densely populated areas. Five specific dangers associated withthe system in such areas are worth underscoring (Cogger, Online;AGWT, Online; Maestas & Clark, 1978). First, the capacity of somesoils, such as clay and sand, to absorb seepage from pits is low. Thisusually dictates the need for more expensive holding tanks instead

.g Planning in Contemporarylopment in Africa (Ashgate,Planning and Public Health iner-reviewed articles.

Elsevier Ltd.

of absorption pits. Second, in densely populated areas, whereseptic-tank use is intense, the tanks must be frequently emptied bytankers. Apart from the high cost involved, the process isunpleasant and constitutes a nuisance to adjacent activities. Third,septic tanks have a tendency to fail and pollute the environment aswell as contaminate groundwater (Maestas & Clark, 1978). Fourth,septic tanks are susceptible to damage by tree roots, which havebeen known to rupture and/or clog the tanks (Cogger, Online;AGWT, Online). Five, some pollutants, such as sulfates, can bereduced to hydrogen sulfide, a pungent lethal gas, under theanaerobic conditions of a septic tank (Cogger, Online; AGWT,Online).

A time-tested method of human waste disposal is via a centralsewerage disposal system. The corpus of this system is a centralsewage treatment plant. Human and domestic wastes withina given municipality are collected and emptied into this plantthrough indoor plumbing and a network of outdoor (underground)pipes. Thus, a central sewerage system can be defined as a networkof pipes and other plumbing accessories designed to dispose liquidor water soluble wastes from domestic and or industrial facilitiesinto a centralized sewage treatment plant. This system, which istypically owned and operated by local governments, and occa-sionally by private corporations, is rare in Africa. Most of the fewthat exist were developed by colonial governments. One cannothelp pondering why these governments decided to develop suchsystems in some colonial towns but not others. What factorsinfluenced this decision? This important but largely ignoredquestion is the focus of the study reported in this paper.

A.J. Njoh / Habitat International 38 (2013) 207e213208

The paper is organized as follows. The next section reviews theliterature on colonialism as a determinant of development in Africa.Following this is an overview of the urban sanitation situation onthe continent. This is followed by a discussion of the methodolog-ical issues of the study. Emphasis is placed on the data, data sourcesvariables and analytical techniques employed. Two subsequentsections respectively present and discuss the main findings of thestudy.

Colonialism and development in Africa

Africa boasted a few prominent human settlements prior to theEuropean conquest. Some of these settlements would be consid-ered large towns by contemporary standards (see e.g., Anderson &Rathbone, 2000; Coquery-Vitrovitch, 1991; Hull, 1976; Ki-Zerbo,1978; Njoh, 2006). By the onset of the European colonial era inAfrica in the late-1800s, most of these settlements were no longerin existence. Thus, the roots of most of the continent’s contempo-rary largest cities are traceable to the colonial era and not itsancient history (Home, 1997; Njoh, 2007). In other words, and asRobert Home (1997) would say, European colonial powers areresponsible for planting almost all major towns and cities in Africa.Students of African urban history have provided detailed accountsof the colonial origins of capital and other influential cities on thecontinent. With the exception of a recent piece by Njoh andAkiwumi (2011), these accounts have been mainly descriptive.Furthermore, hardly any of the studies has treated the planting oftowns as a colonial development endeavour.

The literature on colonialism and development can be roughlygrouped into three categories. First, there are the works that treatdevelopment/underdevelopment in Africa as a function of colo-nialism in general (see e.g., Amin, 1989; Bauer, 1972; Duignan &Gann, 1975; Rodney, 1982). The second group consists of worksthat attribute development outcomes on the continent to erst-while colonizer’s identity (see e.g., Agbor, Fedderke, & Viegi,2010; Bossuroy & Cogneau, 2009; Lee & Schultz, 2009; Njoh,2000). Finally, there are the works that consider colonial tenureor duration of colonial experience as an important determinantof a country’s development profile (see e.g., Njoh & Akiwumi,2011).

Development as a function of colonialism in general

There have always been questions regarding the consequencesfor weaker groups when they are conquered by powerful ones.However, it was not until the onset of the European colonial era inAfrica in the 19th century that these questions were seriouslydebated. To be sure, similar questions had been inspired by, anddebated during, the Age of Enlightenment. The Enlightenment Ageemphasized the universality of human nature, reason, beauty andnatural liberty. In doing so, it stood in sharp contrast to colonialism,which stressed difference and hierarchy. Some of the leadingthinkers of the time, such as Immanuel Kant (in his essay on“Perpetual Peace”) condemned imperialism and colonialismoutright. These criticisms were fresh on the minds of colonialauthorities when the colonial period began in Africa in the late-1800s. Accordingly, these authorities found it necessary to ratio-nalize colonialism as a mission to develop what in the eyes ofEuropeans were ‘socio-economically and culturally backwardregions/peoples.’ The question that has preoccupied analysts of thecolonial enterprise relates to the extent to which it succeeded inrealizing this mission. This question is complicated by many factorsnot least of which is the fact that the link between colonialism anddevelopment is non-linear (Njoh & Akiwumi, 2011). All countriesthat experienced colonialism do not have identical development

profiles. In fact, a number of erstwhile colonies have developmentprofiles that are superior to those of some countries that have neverexperienced colonialism. For example, Australia, Canada, NewZealand, and the United States, which experienced colonialismhave a better development profile than Greece, Portugal and Italythat have never had such an experience.

However, it is worth noting that the aforementioned erstwhilecolonies with impressive development profiles were of the settlervariety. No such colonies existed in Africa. Thus, the continentprovides an ideal context for addressing the question of whethera link exists between colonialism and development. The attemp-ted responses to this question can be grouped into two diamet-rically opposed categories. The first of these categories containsresponses from liberal analysts. These analysts identify the infra-structure development projects that were executed by colonialgovernments as proof of colonialism’s contribution to develop-ment in Africa (see e.g., Bauer, 1972; Gandy, 2006). It is true thatEuropean colonial powers did a lot to ‘modernize’ the territoriesthey controlled throughout Africa during the heydays of colo-nialism. The question that often arises is hardly about thisincontestable fact. Rather, the question typically has to do withwhom these modernization projects were meant to benefitdthecolonizers or the colonized?

The second category contains responses from dependencytheorists. These theorists, including, for example, Samir Amin (e.g.,1972) and Walter Rodney (e.g., 1972), contend that colonialismessentially underdeveloped Africa. Thus, theorists of this persua-sion view colonialism as inversely linked to development in Africa.For dependency theorists, there is no question with respect to thebeneficiaries of colonial development projects. They claim, forinstance, that colonial public infrastructure projects were driven bythe capitalist concerns of colonial powers. Thus, despite the factthat these projects depended on the forced labour input of Africans,Africans were never the projects’ primary beneficiaries. Also, asWalter Rodney (1982) contends in How Europe UnderdevelopedAfrica, the financial and other resources that were necessary tocomplete the projects came from Africa. These claims are notwithout merit. For instance, the forceful extraction of labour fromAfricans in order to complete colonial infrastructure developmentprojects was standard practice in colonial Africa (Njoh & Akiwumi,2011). Colonial governments, because they operated on shoe-stringbudgets, could not complete these projects without free labourinput from Africans.

However, it would appear that the claims of dependencytheorists are blown out of proportion. For instance, it is true thatlabour was forcefully extracted from Africans as a cost-savingstrategy. Yet, it is sheer exaggeration to claim that this holdstrue for all the resources that went into completing everyinfrastructure development project in Africa. One piece ofevidence that is diametrically opposed to this claim has beenuncovered by Njoh and Akiwumi (2011). They drew attention tothe fact that Britain had funded some colonial infrastructuredevelopment projects during the tenure of Joseph Chamberlainas the British Secretary of State. To bolster their assertion, theyinvoke the case of the KenyadUganda railway (Pedler, 1975).This project was completed with interest-free loans from theBritish imperial government. To appreciate the contribution ofsuch a project to development, one needs to simply recognizethe historical and contemporary regional socio-economic role ofthis railway. Some researchers have actually sought to quantifythe impact of pieces of public infrastructure inherited from thecolonial era on contemporary development initiatives in Africa.Jeffrey Herbst’s (2000) study is a case in point. The studyrevealed that inherited road stock explained up to 70 percent ofthe variance in road inventory in Africa in 1997.

Table 1Water and sanitation coverage for West & Central Africa, 2008.

Country Total pop.(1000s)

Surfacearea (km2)

Percenturban pop.

Improvedsanitationcoverage (%)

Urban Rural

Benin 8662 112,622 41 24 4Burkina Faso 15,234 274,200 20 33 6Cameroon 19,088 475,440 57 56 35Cape Verde 499 4033 60 65 38C. African Rep. 4339 622,984 39 43 28Chad 10,914 1,284,000 27 23 4Congo (DR) 64,257 2,344,858 34 23 23Congo (PR) 3615 342,000 61 31 29Cote d’Ivoire 20,591 322,462 49 36 11Equatorial Guinea 659 28,051 39 e e

Gabon 1448 267,667 85 33 30Gambia 1660 11,295 57 68 65Ghana 23,351 238,500 50 18 7Guinea 9833 255,857 34 34 11Guinea Bissau 1575 36,125 30 49 9Liberia 3793 99,067 60 25 4Mali 12,706 1,240,192 32 45 32Mauritania 3215 1,031,00 41 50 9Niger 14,704 1,267,000 16 34 4Nigeria 151,212 923,768 48 36 28S.Tome/Principe 160 964 61 30 19Senegal 12,211 196,722 42 69 38Sierra Leone 5560 72,740 38 24 6Togo 6459 56,785 42 24 3

Source: compiled based on data from WHO/UNICEF (2010). Available online at:figures on surface area are from the US CIA Factbook: https://www.cia.gov/library/publications/the-world-factbook/wfbExt/region_afr.html.

A.J. Njoh / Habitat International 38 (2013) 207e213 209

Development as a function of the colonizer’s identity

Some studies of the link between colonialism and developmentfocus on the identity or nationality of the colonizing power. In thiscase, it is typically hypothesized that the identity of the colonizer,a binary variable, significantly affects development outcomes inthe erstwhile colonies (see e.g., Bossuroy & Cogneau, 2009; Grier,1999; Lee & Schultz, 2009; Njoh, 2000). Consensus is lackingamong studies in this category as they have thus far arrived atdifferent, and sometimes, opposite conclusions. For example, ina study of 26 sub-Saharan African countries in the 1990s, Bossuroyand Cogneau (2009) brought forth evidence suggesting as follows.The development profiles of erstwhile French colonies were betterthan those of countries that experienced British colonialism.Contrary evidence is presented by two similar studies respectivelyby Agbor et al. (2010), and Grier (1999). These studies revealedthat erstwhile British colonies outperformed countries that expe-rienced French colonialism. These latter findings are bolstered bya study based on 45 African countries. The study uncoveredevidence suggesting that educational attainment is higher informer British colonies than in those countries that were colo-nized by France (Cogneau, 2003). This imbalance, the study notedpersisted for several years subsequent to the conclusion of thecolonial era in these countries.

Development as a function of the duration of colonialism

Studies in this category are typically interested not only in theimpact of colonialism in general on development. They are inter-ested in how different colonial durations affect development in thecolonized territories during, and subsequent to the demise ofcolonialism. One example is by Cogneau (2003). This study wasbased on 70 former colonies currently considered developing ordeveloped nations. It found that the scale of European settlementhad a significant impact on the level of per capita income andincome inequalities in these countries. In a more recent study, Njohand Akiwumi (2011) analyzed access to improved water and sani-tation as a function of duration of colonial era in Africa. They foundthat access was greater in countries which experienced longerperiods of colonialism. The researchers were quick to state thattheir aim was not to endorse colonialism as a viable developmentstrategy. Rather, the aim was to shed light on the fact that despiteits moral reprehensibility, colonialism laid the foundation for urbandevelopment initiatives throughout Africa.

Access to improved sanitation in urban Africa

To appreciate the importance of central sewerage systems, theymust be understood within the broader context of improved sani-tation facilities. The definition of improved sanitation facilitiesproffered by the World Health Organization (WHO) and UnitedNations Children’s Fund (UNICEF) can be paraphrased as follows.These are facilities that are capable of effectively preventinghuman, animal and insect contact with excreta (WHO, 2007). Forlogistical and administrative reasons, UNICEF and cognate inter-national development agencies have divided Africa into threemajor regions. These regions include West and Central Africa (seeTable 1), East and Southern Africa (see Table 2), and Northern Africa(see Table 3). West and Central Africa stretches from Mauritania inthe northwest to Congo (DR) in the southeast. East and SouthernAfrica includes the region stretching from Eritrea in the northeastthrough Uganda, Burundi and Rwanda in the middle belt andAngola to the West, Madagascar to the east, and down to SouthAfrica in the south. Urban sanitation conditions on the continenttoday differ considerably by these regions.

West and Central Africa

This is the region with the worst sanitation conditions in Africa.Only 27% (or 105 out of 396 million) of the population in this regionhas access to improved sanitation facilities (UNICEF, Online). AsTable 1 shows, the urban sanitation coverage in the region rangesfrom a dismal 18% for Ghana to a high of 69% for Senegal. Particu-larly noteworthy is the fact that these statistics reflect a vastimprovement over the last few years.

Barely five years ago, only one country, Gambia, in the regionhad an urban sanitation coverage greater than 50%. Today, asTable 1 reveals, sanitation coverage in four countries in the region,including Senegal (69%), Gambia (68%), and Cape Verde (65%), havereached or exceeded 50%. In contrast, as the table shows, sanitationcoverage in the rural areas remains very poor, and range from a lowof 3% for Togo to 68% for Gambia.

East and Southern Africa region

Sanitation coverage in this region ranges from 15% forMadagascar to 86% for Angola (see Table 2). As Table 2 shows,countries in the region diverge considerably with respect to sani-tation coverage. On one extreme are countries such as Madagascar,Kenya and Ethiopia, where less than 30% of the urban populationhas access to improved sanitation facilities. On the other extremewe find Seychelles, South Africa and Angola, where more than 80%of the urban population is served by improved sanitation infra-structure. One manifestation of serious deficiencies in improvedsanitation coverage in the region is the percentage of the pop-ulation that practices open defecation. This incidence is highest inEritrea, where as much as 41% of the urban population defecates inthe open (Table 2). As bad as this statistic is, it pales significantly incomparison to what obtains in rural areas. As the table shows, 96%of the country’s rural population practices open defecation.

Table 2Sanitation conditions in the Eastern and Southern Africa region.

Country Population (�1000) Urban (%) Rural (%)

Improved Shared Unimproved Open defecation Improved Shared Unimproved Open defecation

Angola 86 e 13 1 18 e 29 53Botswana 1921 74 7 18 1 39 11 12 38Burundi 8074 49 22 27 2 46 4 49 1Comoros 661 50 3 46 1 30 2 68 0Eritrea 4927 52 e 7 41 4 e 0 96Ethiopia 80,713 29 34 29 8 8 2 19 71Kenya 38,765 27 51 20 2 32 18 32 18Lesotho 2049 40 35 17 8 25 3 21 51Madagascar 19,111 15 28 39 18 10 17 35 38Malawi 14,846 51 42 5 2 57 24 8 11Mozambique 22,383 38 7 41 14 4 1 36 59Namibia 2130 60 17 5 18 17 4 6 73Rwanda 9721 50 18 31 1 55 6 36 3Seychelles 0.892 97 e 2 1 e e e e

Somalia 8926 52 30 15 3 6 6 5 83South Africa 49,668 84 10 4 2 65 9 9 17Swaziland 1168 61 32 5 2 53 20 6 21Tanzania 42,484 32 30 36 2 21 21 41 17Uganda 31,657 38 56 4 2 49 22 18 11Zambia 12,620 59 22 17 2 43 9 22 26Zimbabwe 12,463 56 40 2 2 37 15 9 39

Source: based on data from WHO/UNICEF (2010).

A.J. Njoh / Habitat International 38 (2013) 207e213210

North Africa

The North Africa region experiences the best sanitation condi-tions on the continent. As Table 3 shows, access to improvedsanitation for urban residents in the region ranges from 55% forSudan, to 98% for Algeria. Sudan is also peculiar in the region for thepercentage (20%) of the urban population that practices opendefecation. However, it is important to note that large segments ofthe rural population of countries in the region have no access toimproved sanitation facilities. Consequently as much as a fifth ofthis population resoughts to defecating in the open. In countriessuch as Algeria, where almost all urban residents have access toimproved sanitation, as much as 20% of the rural population defe-cates in the open. If nothing else, this is indicative of the problem ofurban bias in infrastructure provisioning that was set in motion bycolonial authorities.

It is easy to understand the regional disparities in sanitationfacilities noted above once we acknowledge the role of colonialismin public infrastructure building in Africa. In this regard, it is hardlysurprising that West Africa emerges as the region least endowedwith sanitation facilities. This is because from the onset, colonialauthorities had decided against settling permanently in the region.Several reasons informed this decision. First, the region was char-acterized as a bastion of the malaria vector or the ‘Whiteman’sgrave,’ and therefore unsuitable for European settlement. For thisreason, colonial authorities made very minimal investment ininfrastructure building. The story was different in the case of

Table 3Sanitation conditions in the Northern Africa region.

Country Population (�1000) Urban (%)

Improved Shared Unimproved

Algeria 34,373 98 n/a 1Egypt 81,527 97 3 0Libya n/a n/a n/a n/aMorocco 31,606 83 14 3Sudan 41,348 55 n/a 25Tunisia 10,169 96 2 2Western Sahara n/a n/a n/a n/a

Source: based on data from WHO/UNICEF (2010).

Eastern and Southern Africa. Here, especially in countries such asZimbabwe, South Africa and Namibia, Europeans decided in favourof setting up permanent European settlements. Commensurately,colonial authorities proceeded to develop extensive sanitation andother networks. The case of North Africa is identical to that of Eastand Southern Africa. French colonial authorities were bent oncreating mini versions of French towns, complete with sanitationand other public facilities in North African capital cities such asTunis, Algiers and Casablanca.

Hypotheses

To the extent that such facilities take time to be developed, it ishypothesized that the longer the colonial period, the more exten-sive the sanitation infrastructure. This general hypothesis wasbroken down for the purpose of the study discussed here as follows.

Hypothesis I: A multivariate model containing colonialism,operationalized in terms of duration of colonial era, thegovernment share of real GDP per capita at the time of inde-pendence, and the colonial power’s nationality as predictorvariables is capable of predicting the presence/absence ofcentral sewerage system in any African country at the time ofindependence.Hypothesis II: Urban centres in countries with a longer history ofcolonialism are more likely than those in which the colonial erawas brief to have a central sewerage system. As defined above,

Rural (%)

Open defecation Improved Shared Unimproved Open defecation

1 88 n/a 2 100 92 6 2 0n/a n/a n/a n/a n/a0 52 6 4 3820 18 n/a 24 580 64 8 14 14n/a n/a n/a n/a n/a

A.J. Njoh / Habitat International 38 (2013) 207e213 211

a central sewerage system comprises a network of pipes andother plumbing accessories designed to dispose liquid or watersoluble wastes from domestic and or industrial facilities intoa centralized sewage treatment plant.Hypothesis III: The nationality (or identity) of the colonialpower is likely to be a viable predictor of the presence/absenceof a central sewerage system in urban Africa at the time ofindependence.Hypothesis IV: A country’s government share of real GDP percapita is likely to be a viable predictor of presence/absence ofcentral sewerage system in urban Africa at the time ofindependence.

The next section describes the methodological issues involvedin efforts to test these hypotheses. It begins with a description ofthe data sources and analytical techniques employed in the process.

Methodological issues

Data and data source

The data for this study originated in fourmain sources, includingthe following: 1) the Penn World Tables; 2) the US Central Intelli-gence Agency (CIA) World Factbook; 3) the World HealthOrganization (WHO)/the United Nations Children’s Fund(UNICEF), Joint Measurement Programme (JMP), and 4) IWAWater Wiki (see iwawaterwiki.org).

The Penn World Table constituted the source of data on theGDP per capita for 1960 on all of the countries examined. Operatedby the University of Pennsylvania, the website for these data iscomprehensive. It contains a wide range of economic data on 189countries/territories throughout the world from 1950 to 2009 (seeHeston, Summers, & Aten, 2009). The period of concern is from thebeginning of the colonial era (circa, 1800s) to 1960. The 1800smark the time when European colonial powers began acquiringterritories in Africa. Although the official onset of the colonial erain Africa was 1884/85, many territories in the region had beenextended protectorate status before then. The year in whicha country was extended such status is considered the point atwhich the country began experiencing colonialism. The year 1960is taken to mark the demise of European colonialism in Africa.Certainly not all countries gained independence at that time. Forinstance, Zimbabwe did secure independence from Britain untilthe 1980s. However, most countries on the continent becameindependent in 1960.

The CIA World Factbook served as the main source of data onthe identity of erstwhile colonial powers, urbanization levels anddevelopment profiles of African countries (see CIA, Online). TheCIA World Factbook is available in hard copy and online. Itcontains reliable and up-to-date data on the geography, people,government, economy, communications, transportation, the mili-tary, and international affairs of all sovereign nations in the world.Since 1981, the publication, which used to be released semi-annually, has been published every year. It was first made avail-able online in June 1997.

The ‘World Bank Data Online,’ contains up-to-date statistics onliving conditions throughout the world (see data.worldbank.org).The database contains information in Arabic, English, French andSpanish on more than 2000 indicators, including hundreds datingback about half-a-century. This source provided statistics on accessto sanitation for urban Africa. The original source for these statisticsis the World Health Organization (WHO) and the United NationsChildren’s Fund (UNICEF), Joint Measurement Programme (JMP).The data could not be directly accessed because the relevantUniversal Resource Locator (URL) was dead.

IWA Water Wiki is an online Global Water Community, whichprovides a wealth of data on water, wastewater and environmentalscience and management throughout the world (seeiwawaterwiki.org). The website contains professional and schol-arly articles on the ‘sanitation status’ of almost all major cities inAfrica. The articles served as the main source of data on theavailability or lack thereof of central sewerage systems in thevarious cities examined here.

Variables and measurements

The study included four different variables, one of which isthe dependent variable (DV) and the rest, independent variables(IVs). The DV is CENSWG (central sewerage system). It isa dichotomous variable, which took on the value ‘1’ if a city wasequipped with a central sewerage system by 1960, and ‘0’ if nosuch system existed in the city at that time. The IVs included: 1)the number of years that a country spent as a European colony(YRSCOL); 2) the government share of real GDP per capita in 1960(GDP60); and 3) the nationality of the colonial power (COLID). Allbut COLID are continuous variables. COLID is a dummy variable,which assumed the value ‘1’ if the colonial power was Britain,and ‘0’ otherwise. A word on the variable, GDP60, which is notself-explanatory, is in order. This variable is included as a proxyfor gauging the level of commitment by a colonial power in anygiven colony. As defined by the United Nations (UN.Org, Online),the government share of real GDP per capita measuresa government’s share of investment with respect to totalproduction. It is measured in percentages and “obtained bydividing gross production capital formation by gross domesticproduct, both at purchasers’ prices” (UN.Org, Online).

Data analysis

The desktop version of the Predictive Analytic SoftWare (PASW)(Version 19) was used in the ‘Windows XP’ environment tomanipulate the data for the study. Formerly known as the StatisticalProgram for Social Sciences (SPSS), the program is the most widelyused in social science. The logistic model was used to analyze thedata. Also known as the logit model, this model is apropos forsituations involving a DV that is dichotomous as opposed tocontinuous. As stated above, the DV for the study is ‘centralsewerage system,’ which can either be available or not available ina given city. Because this variable can assume only one of twovalues (in this case, 1 or 0), it violates the assumption inregression analysis that DVs should be continuous (see e.g.,Berman, 2005). Alternative models would have been unsuitable inthis situation.

Model specification

LogitðYÞ ¼ natural logðoddsÞ ¼ ln�

P1� P

�¼ aþ bX þ u (1)

where P is the value of the DV and varies between 0 and 1. Expo-nentiating both sides of this equation, we obtain the following:

P ¼ 11� e�ðaþbXþuÞ (2)

If bX ¼ þN, P ¼ 1, and when bX ¼ �N, P assumes the value 0.Therefore, P is always going to be located between 0 and 1.In the context of the study reported here, P or CENSWG (i.e.

availability of central sewage) will always be either ‘0’ when a citylacks a central sewage system or 1 when it has one.

Table 4Description statistics for variables in the logistics model.

Variable Total sample (N) Dummycode

Minimum Maximum Mean Std. dev.

1 0

GDP60 42 n/a n/a 2.60 56.3 15.23 12.95YRSCOL 49 n/a n/a 38 162 79.94 25.49CENSWG 52 11 41 n/a n/a n/a n/aCOLID 52 19 33 n/a n/a n/a n/a

A.J. Njoh / Habitat International 38 (2013) 207e213212

The equation can be restated for the study reported here toassume the following form:

ln�

CENSWG1� CENSWG

�¼ aþ bðGDP60Þ þ bðYRSCOLÞ

þ bðCOLIDÞ þ u(3)

The ‘goodness-of-fit’ for the resultant model is tested with thehelp of the following 3 related statistics (Berman, 2005). The first isthe log likelihood value (�2LL), which is similar to, but not exactlythe same as, the F-statistic in ‘regular’ regression analyses. Thesecond is the Cox and Snell R-square, which is similar to the coef-ficient of multiple determination in multiple regression although itcan never attain the value of 1.0. The last goodness-of-fit testemployed is the Nagelkerke R-square, which resembles theadjusted coefficient of multiple determination in that it compen-sates for the problem of Cox Snell statistics never attaining 1.

Main findings

Table 4 contains the descriptive statistics for variables in thelogistic model. The table shows that the government share of realGDP per capita in 1960 (GDP60) for African countries ranged fromalmost 3% (2.65) to 56% (56.3%), with a mean of 15% (15.23%) anda standard deviation of about 13% (12.95%). According to the table,the duration of colonialism ranged from 38 to 162 years, witha mean of about 80 years and a standard deviation of almost 26(25.49) years. Nineteen (or 36.5%) of the 52 countries included inthe study experienced British colonialism (see Dummy Code ‘1’ onTable 4). The table further shows that 21%, or 11 of the 52 countriesexamined had a central sewage system in an at least one town by1960.

Upon fitting the model with one dependent variable, CENSWG,and three predictor variables, viz., GDP60, YRSCOL, and COLID tothe data, we obtained the results summarized in Table 5. The aimwas to test the hypothesis that the availability of a central seweragesystem in any city prior to 1960 is a function the following attri-butes of the country in which the city is located: 1) duration asa colony; 2) GDP in 1960; and 3) erstwhile colonizer’s nationality.The results shown on the table support Hypothesis I (see above).According to the table, about 32% (31.7%) of the variance in avail-ability of central sewerage system is accounted for by colonialism.Additional statistics appearing at the bottom of the table lend

Table 5Logistics regression analysis of availability of central sewerage system as a functionof colonialism.

Predictor b SE b Wald’s c2 df p Odds ratio

Constant �4.336 1.672 6.721 1 0.100 N/AYRSCOL 0.046 0.021 4.933** 1 0.026 1.047GDP60 �0.083 0.075 1.230 1 0.267 0.920COLID 0.214 0.955 0.050 1 0.823 1.239

Notes: **significant at p < 0.05; �2log likelihood: 33.689; Cox & Snell R2: 0.206;Nagelkerke R2: 0.317; predictive power of model as a whole: 82.9%.

credence to this interpretation. Note that the overall ability of themodel to make the correct prediction is about 83% (82.9%). Thissuggests a strong predictive power as standards of 80e85% areregarded as strong (Berman, 2005).

Themodel capturing this relationship between the DV and IVs inthe study can be mathematically represented as follows:

Predicted logit of CENSWG ¼ �4:336þ 0:046YRSCOL

� 0:083GDP60þ 0:214COLID

The equation suggests that the log of the odds of a city havinga central sewerage system before independence (1960) is positivelyassociated with duration of colonial experience, but negativelyrelated to the 1960 GDP of the country in which the city is located.However, it is worth noting that while the relation involvingavailability of central sewerage system and duration of colonialismis statistically significant (p < 0.05), that involving the 1960government share of real GDP per capita is not. Thus, this latterrelationship may just be a function of chance. Also not statisticallysignificant is the relationship between availability of centralsewerage prior to independence and the dummy variable colonialidentity. Thus, while Hypotheses I and II are supported by thefindings, Hypotheses III and IV are not. In the following section,which concludes the paper, an attempt is made to explain thesethought-provoking revelations.

Discussion of findings

As stated at the onset of this paper, the study reported herebuilds on a recent study by Njoh and Akiwumi (2011). However, itdiffers from said study in substantive and methodological terms.The Njoh and Akiwumi study examined access to improved waterand sanitation in general. In contrast, the study presented hereconcentrates on an important but often ignored aspect of urbansanitation in Africa, namely central sewerage systems. Methodo-logically, the Njoh and Akiwumi study employs the multipleregression technique while the study reported here uses the logitmodel. Like Njoh and Akiwumi, the present study has uncoveredempirical evidence upholding colonialism as a viable predictor ofsanitation conditions in Africa.

In particular, the study affirms the hypothesis of a positiveassociation between colonial tenure and the availability of a centralsewerage system. To comprehend the tenor of this finding, it isnecessary to appreciate central sewerage systems within thebroader context of public infrastructure. A defining characteristic ofpublic infrastructure is its sheer cost. The high cost associated withpublic infrastructure projects means only national or localgovernments possess the wherewithal to develop them. This wasparticularly true during the colonial era when local non-governmental entities possessed no resources of their own. Thus,the decision to develop any piece of public infrastructure, it follows,could never have been taken lightly. The question, then, is: whatfactors influenced such decisions? The study reported here hassucceeded in identifying one such factor, namely duration of thecolonial era.

As a predictor of colonial infrastructure development initiatives,duration of colonialism possesses both a logical and an intuitiveappeal. Public infrastructure development projects require not onlyfinancial resources. They require time, and more so during thecolonial era when the technology necessary for undertaking suchprojects was relatively rudimentary. The costly nature of suchprojects meant that colonial powers could only develop themin territories intended for permanent European settlement.This explains the fact that Algeria, Tunisia, South Africa, SouthernRhodesia (present-day, Zimbabwe), and Namibia, which boast

A.J. Njoh / Habitat International 38 (2013) 207e213 213

permanent European settlements, have central sewerage systemsdating back to the colonial époque. It is true that central seweragesystems as well as other improved sanitation systems were initiallyconfined to exclusive European enclaves in colonial Africa (Njoh &Akiwumi, 2011). However, with the passage of time, the impera-tives of colonial governance dictated a need for these facilities to beextended to non-European districts. Such extensions occurredespecially during the twilight of the colonial era, and were inreaction to complaints of relative deprivation from Africans. Thus,extending sanitation infrastructure beyond exclusive Europeanenclaves was designed to ‘win the hearts and minds’ of Africans. Itis therefore hardly any wonder that by the 1960s African townswith significant European populations boasted extensive sanitationcoverage complete with central sewerage systems.

The central question addressed here is of historical andcontemporary importance. Answers to the question can facilitateunderstanding of the raison d’être of colonial urban developmentinitiatives in Africa. Also, knowledge of these initiatives canenhance comprehension of Africa’s contemporary urban condition.As some analysts (e.g., Grier, 1999; Herbst, 2000; Njoh & Akiwumi,2011) have been quick to point out, colonial development activitiesconstitute a viable predictor of contemporary national develop-ment profiles in Africa.

This paper started off by drawing attention to the fact that septictanks have outlived their utility in urban Africa. In fact, septic tanksconstitute a health and safety hazard in the densely populated andrapidly proliferating urban centres. In their stead, central seweragesystems are proposed. National and municipal governments inAfrica will do well to craft strategies for developing such systems.To be successful, such strategiesmust incorporate aspects of Africanethos, such as citizen participation or communal work. Communalwork, whether voluntary or involuntary, constituted a majorcomponent of colonial public works projects such as centralsewerage systems. Seen from this perspective, colonialism, andespecially colonial governance holds invaluable lessons for entitiesseeking to ameliorate living conditions in urban Africa.

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