INTERNATIONAL JOURNAL OF URBAN SUSTAINABLE DEVELOPMENT 2019, VOL. 11, NO. 2, 172–188 https://doi.org/10.1080/19463138.2019.1618859 ARTICLE Undertaking Urban Metabolism analysis in a data poor context: the metabolism of housing construction materials in Amdework - a small town in Ethiopia a,b a b Teshome Tefera Tola , Ahmed Z. Khan and Fisseha Wegayehu a b ULB (Universite Libre de Bruxelles); EiABC, AAU (EiABC, Addis Ababa University) ABSTRACT ARTICLE HISTORY Received 29 December 2018 Urban Metabolism, a tool used to map and quantify ﬂows and stocks within and Accepted 10 May 2019 across urban boundaries, has become an important tool in recent urban studies. It shows the relative position of a town (its sub-system) on the sustainability con- KEYWORDS tinuum. However, the approach faces critical bottlenecks, particularly, in developing Urban Metabolism; countries, because of lack of data and standardised methodologies. This research, by sustainable development; employing a bottom-up data generating technique that relies on lots of conversions small town; carbon and estimations, analyses the metabolism of materials used in the construction of footprint; construction materials residential housing in a small town in Ethiopia. The result indicates that the vast majority of inputs used in the construction are sourced locally. However, there are certain worrisome trends challenging sustainability in the sub-system. Furthermore, ﬁndings of the metabolic analyses have been extrapolated to the national-level to understand implications ﬂows and sourcing of inputs have on the sustainability of low-income housing in the future. 1. Introduction urbanisation in those countries. And, in order to ensure their long-term existence and ease pressures Urbanisation in developing countries is faced with created by these interwoven challenges, towns and immense challenges. Towns and cities in those coun- cities need to capitalise on the sustainable develop- tries are already stressed and severely lack many ment path in the coming years and decades. Williams essential infrastructures and services gravely needed (2010), Currie et al. (2015) and Ferrão and Fernández by their citizens (Williams 2010; Ferrão and (2013) indicate that the sustainable path oﬀers solu- Fernández 2013; Currie et al. 2015; Currie and tions to some of these challenges towns and cities of Musango 2016). Some of the challenges, as discussed developing countries are currently facing. in various literatures, are prevalence of slum dwell- It is argued in Athanassiadis et al. (2018); Ranzato ing; shortage of food; shortage of infrastructures and et al. (2018b); Currie et al. (2015) and Ferrão and services; unemployment, poverty and etc. For Fernández (2013) that studying urban metabolism instance, slum dwelling in Sub-Saharan African and helps to understand the long-term sustainability of South Asian countries stand at 62% and 43%, respec- diﬀerent activities and ﬂows taking place in these tively. And, the ﬁgure is much worse in developing towns and cities. Urban metabolism study, according countries like Ethiopia, where 70–80% of the total to these authors, requires quantiﬁcation of inputs, urban housing stock is categorised as slum ([UN- outputs and activities taking place in and outside HABITAT] United Nations Human Settlements the cities and towns under consideration. These Programme 2007; World Bank, Government of quantities help to understand the way urban systems Ethiopia, Cities Alliance 2015). These challenges and sub-systems function. pose a major threat to the current and future CONTACT Teshome Tefera Tola firstname.lastname@example.org ULB (Universite Libre de Bruxelles) © 2019 Informa UK Limited, trading as Taylor & Francis Group INTERNATIONAL JOURNAL OF URBAN SUSTAINABLE DEVELOPMENT 173 However, as discussed in Ferrão and Fernández research. Major ﬁndings, discussions and the implica- (2013); Currie et al. (2015) and Currie and Musango tion of the research on policies and future urbanisa- (2016), there are many challenges that limit the appli- tion in the country are thoroughly presented in cation of the Urban Metabolism framework in devel- Section 4. The last section, Section 5, ﬁnally presents oping countries’ context. Many of these challenges concluding points about the ﬁndings and implica- are related to quantiﬁcations of variables that are tions of this research. important to characterise inputs, outputs and activ- ities in urban areas. These authors precisely indicate that the analysis of Urban Metabolism in such coun- 2. Concepts and deﬁnition tries face challenges because of the following rea- 2.1. Deﬁnitions and brief summary about Urban sons. These are: (1) Lack of data and quality data at Metabolism town or city levels; (2) diﬃculty to follow and quan- tify undocumented informal ﬂows of inputs or out- Scholars have been trying to understand relation- puts; (3) inconsistency of units and formats used for ships towns and cities have with their surrounding the available data; and (4) lack of comprehensive and using diﬀerent approaches. One of these approaches standardised methodologies to quantify and is the Urban Metabolism approach. Ranzato et al. analyse the ﬂows of resources. (2018a); Zhang (2013) and Pincetl et al. (2012) claim The aforementioned challenges make the devel- that the concept of Urban Metabolism was ﬁrst intro- opment a new feasible framework that can be used duced by Karl Marx in 1883. The concept of Urban to study the metabolism of towns and cities in devel- Metabolism ﬁrst discussed by Marx had not been oping countries an important task. Scholars like Niza researched and expanded by subsequent researchers et al. (2009), Currie et al. (2015) and Ferrão and for more than a century. It was then reintroduced to Fernández (2013) recognised the existence of such the urban study only after Abel Wolman’s article challenges and forwarded diﬀerent approaches as to entitled as ‘The Metabolism of Cities’ in 1965. how to generate and use data to study Urban Wolman’s work was a pioneering one as it relied on Metabolism in developing countries. quantities to visualise the environmental footprint The main objective of this research is, therefore, to a city, his ideal city of 1 million people, which develop a clear methodology that helps to overcome extends beyond the city’s boundary into the region. the data shortage and understand, quantify and map Following Wolman’s contribution, according to the metabolism of construction materials of residen- Kennedy et al. (2010), the period of 1970s marks tial houses in a data poor context (in Amdework, another important period in the study of Urban a small town in Northern Ethiopia), especially empha- Metabolism because it was the time when the ﬁrst sising on Vernacular Stone and Semi-vernacular ‘Chika’ practical studies of Urban Metabolism were con- residential houses that constitute 95% of the hous- ducted in the cities of Tokyo by Hanya and Ambe ing stock in the case town. in 1976; Brussels by Duvigneaud and Denayeyer-De Speciﬁcally, this research aims to: develop a clear Smet in 1977 and Hong Kong by Newcombe, Kalma methodology that can be used to undertake urban and Aston in 1978. metabolism study in a data poor context; quantify Many scholars have so far deﬁned Urban the ﬂows of construction materials used in the con- Metabolism in related but slightly diﬀerent ways. struction of vernacular stone and semi-vernacular Urban Metabolism, according to Kennedy et al. Chika residential houses in Amdework; map the (2007, p. 44), for instance, refers to ‘the sum total of movement of these materials using Sankey diagrams; the technical and socio-economic processes that occur and, interpret the results of the Sankey diagrams and in cities, resulting in growth, production of energy, and relate it to the sustainable development of small elimination of waste’. The main task of Urban towns across the country. Metabolism, according to this deﬁnition is, therefore, This research has ﬁve sections. Section 1 intro- to understand, analyse, and quantify what comes in duces the topic and objectives of the research. (as an input); what is used and remains inside (as Section 2 where contributions of other researchers energy and/or stock); and what goes out of a town in the ﬁeld are brieﬂy summarised. Section 3 speciﬁes or a city (as an output or waste). This knowledge helps methodological issues, data source and scope of the towns and cities to understand where they are on the 174 T. T. TOLA ET AL. sustainability continuum. It also helps them evaluate both the direct and indirect solar energy utilised in the the extent of exhaustion of closely located critical production of goods and services to quantify ﬂows. resources and propose, if necessary, strategies of slow- However, as indicated in Kennedy et al. (2010)and ing down the exploitation of these critical resources. Pincetl et al. (2012), the ‘emergy approach’ faced chal- Proper accounting of the ﬂows and stocks gives cities lenges and could not grow into prominence because the opportunity to grow from ‘within’ without exert- of the complexity of measurements and conversions ing much pressure on the virgin resources. (of units) associated with it. (Athanassiadis et al. 2016; Ellen MacArthur On the other hand, the second set of approaches Foundation, StiftungsfondsfürUmweltökonomie und that are more interested in measuring the ﬂows of Nachhaltigkeit (SUN) and McKinsey Center for materials have become common in recent years. One Business and Environment 2015, p.13; Currie et al. of these approaches is the Material Flow Analysis – 2015; Ferrão and Fernández 2013). MFA (Ferrão and Fernández 2013; Chen and Chen Urban Metabolism as a discipline has beneﬁtted 2015; Currie et al. 2015). According to Chen and a lot from advancements achieved in the ﬁeld of Chen (2015), the traditional MFA is more concerned Industrial ecology and other related ﬁelds. Other with the physical ﬂow of materials into and out of advancements in the ﬁeld, which recognise the a system. However, later movements in the ﬁeld have potential to grow from within and demystify the started incorporating the environmental impacts and complexities in urban systems, were achieved in socio-economic aspects of the ﬂows. This movement recent years when scholars started researching the resulted in the emergence of second generation role of Veins. These veins, according to Bancheva Urban Metabolists, as Pincetl et al. (2012) and (2014, p. 8) (or alternatively called ‘scavengers in an Goldstein et al. (2013) call them. The contribution of ecosystem’ in Ferrão and Fernández 2013, p. 10), industrial ecologists is huge in this regard (Ferrão transport back the wastes and/or resources that and Fernández 2013). would have ended up in landﬁlls in the linear and But generally, as indicated in Ferrão and unsustainable or cradle-to-the-grave system (Ellen Fernández (2013); Currie et al. (2015); Currie and MacArthur Foundation 2013, p. 23). The veins com- Musango (2016) and Athanassiadis et al. (2016), the plete the loop in the circular ﬂow of resources and ﬁeld of Urban Metabolism suﬀers from the lack of give way for the sustainable development of urban standardisation and harmonisation of methodolo- areas, commonly known as the cradle-to-cradle sys- gies, even in developed countries – where it is rela- tem. This new movement, called the Circular econ- tively easier to get well documented data of human omy in Ellen MacArthur Foundation (2013, p. 6) and activities and ﬂows. This lack of harmonisation of Ferrão and Fernández (2013, p. 10), focuses on clos- methodologies, according to Ferrão and Fernández ing loops and unpacking the complexities of human (2013), has made comparison across regions activities in urban areas. Studying urban metabolism adiﬃcult task. is, therefore, an important indicator developed in In addition to the lack of standardised and harmo- recent decades to gauge the level of sustainability nised methodology, as also indicated in Section 1, of diﬀerent ﬂows and activities in towns and cities. there are also many other challenges of applying the Urban Metabolism approach in the developing coun- tries context. Some of the reasons, according to 2.2. Methodological issues in Urban Metabolism Ferrão and Fernández (2013); Currie et al. (2015) Many scholars have conducted Metabolism analysis of and Currie and Musango (2016), are lack of docu- towns and cities in diﬀerent periods and contexts mented and reliable data; the diﬃculty of following using diﬀerent approaches. As described in Pincetl and quantifying informal ﬂows; inconsistency of et al. (2012), there are two diﬀerent approaches used units; and lack of comprehensive and standardised to quantify ﬂows that come into and leave a given methodologies to quantify and analyse the ﬂows of urban territory. The ﬁrst approach, which is called resources. Odum’sapproach – also called emergy approach, in According to Ferrão and Fernández (2013) and Zhang (2013) and Pincetl et al. (2012) – converts every Kennedy et al. (2007), the volumes of these ﬂows activities and ﬂows to the sole source of energy of the mainly depend on factors like the age of the city, planet, the solar energy. The approach accounts for stage of development (or per capita income of the INTERNATIONAL JOURNAL OF URBAN SUSTAINABLE DEVELOPMENT 175 residents), cultural factors, climate, density, transpor- how to generate data, at least, for the housing sector tation characteristics and morphology of cities, build- that is known for consuming bulky inputs. This meth- ing codes costs of energy, and government policies. odology can be adapted and used in other sub- The authors speciﬁcally mentioned that the stage of systems to understand the metabolism of materials development or per capita income has signiﬁcant in similar towns or cities in the Global South, where impact on the volume of the major resource ﬂows. data is non-existent or scarce to undertake such For Ferrão and Fernández (2013) the direct relation analysis. Secondly, it is important because it is under- between income and material consumption (or taken in a small town located far away, even from ﬂows) becomes stronger especially in transitional a secondary regional city in Ethiopia. Such small and developing economies, because such economies towns are considered to be frontiers of future urba- usually undertake massive infrastructure develop- nisation in the coming years and decades; but have ment works like the construction of roads, railways barely been addressed by similar researches. Hence, and buildings. addressing the issue of sustainability at these fron- Even though understanding the metabolism of tiers is crucial because, as described in introductory towns and cities in transitional and developing coun- section, urbanisation on part of the world is still less tries is important because of their massive infrastruc- that the 50% mark. tural development need, there are few studies undertaken on the issue, particularly on the African continent. Some of these studies undertaken on the 3. Data sourcing, methodological framework metabolism of African towns and cities include: and scope ‘Towards Urban Resource Flow Estimates in Data 3.1. Data sourcing and methodology Scarce Environments: The Case of African Cities’ by Currie et al. (2015); Urban metabolism requires robust data and the ana- ‘Urban Metabolism and Quality of Life in Informal lysis is highly data intensive. This characteristic of Areas’ (conducted in Cairo) by Attia and Khalil (2015); Urban Metabolism may make it a diﬃcult to under- ‘Energy and material ﬂows of megacities’ (con- take such study in developing countries because of ducted in many mega cities of the world including the scarcity of data. However, getting the data and Lagos and Cairo) by Kennedy et al. (2015). doing the analysis has now become a matter of ‘Metabolism of an Emerging Town in Ethiopia: The importance to understand the level of sustainability Case of Amdework’ by Ranzato et al. (2018b) of activities and ﬂows taking place in towns and These studies adopted diﬀerent methodological cities of developing countries. approaches to study the metabolism of those towns As a research project undertaken in a Sub-Saharan and cities. Table 1 summarises the methodological African country – Ethiopia, this study relied on lots of approaches adopted by the authors and some chal- estimations and conversions to ‘generate’ the lenges observed in conducting Urban Metabolism in required data and understand the metabolism of such cities. housing construction materials in the case town. Generally, it is possible to understand, from these Especially, conversion was crucial because local peo- three studies, how hard it is to get data to undertake ple measure materials in terms of local or traditional Urban Metabolism studies in Sub-Saharan African units (such as bundles, number of full truck loads of Towns and Cities. Furthermore, it is also possible to materials, round trips made to transport the items see that all the studies undertaken so far were con- and etc). Hence, conversions to the metric system, ducted in the biggest cities of the continent, where though is cumbersome, becomes a matter of impor- the availability of data is relatively better as com- tance. Estimations were also extensively used, espe- pared to rural towns and secondary regional cities. cially while quantifying the both the inputs and This research, therefore, intends to ﬁll this gap, at outputs. Estimations were important because people least, in two areas. First, it intends to develop are less aware of the importance of properly quanti- a methodology that helps to generate data (through fying, documenting and remembering the amount of estimations and conversion) in such small towns materials used during construction and recovered or where it is diﬃcult or merely impossible to get thrown away after demolition of their old houses. a usable data. It develops a clear methodology on This makes these ﬂows hidden to researchers and 176 T. T. TOLA ET AL. Table 1. Urban Metabolism researches conducted in African Cities (Attia and Khalil 2015; Currie et al. 2015; Kennedy et al. 2015; Ranzato et al. (2018b). No Authors Methodologies and data sourcing 1 Currie et al. (2015) The authors used a top-down approach to get local data. The research relied on data from the World Bank and the UN to generate average ﬁgures for the 160 selected African Cities. The research misses some local and speciﬁc conditions as the data used is calculated from national aggregates in many cases. Reliance on averages also misses the rural-urban and city-small town dichotomies, and many other peculiar conditions which are very visible in many developing countries. The selection process of the 160 cities across the African continent was based on three sets of criteria. One of these criteria is the availability of data which still shows the challenges of getting data even in bigger African cities. It also made the analysis of big cities whose population is over 1 million, which further indicates the challenge of undertaking such analysis in small towns where data is scarce or unavailable. 2 Kennedy et al. (2015) Kennedy et al. (2015) also openly discussed the challenges of getting usable data in cities in the Global South, including two African mega cities, Cairo and Lagos. This research also relied on ﬁgures from international institutions like the World Bank to undertake the study. This also makes it diﬃcult to capture some essential local issues, especially in small towns of Africa. 3 Attia and Khalil (2015) This is a research done on the metabolism of piped water in an informal settlement in the city of Cairo. It analyses the metabolism of water starting from the entry point (inlet) at the Nile River up to its outlet at the water treatment plant. These researchers generated their own data for the study. This was made possible because of the involvement of local and international institutions involved in the project. The collaborators include local universities, NGOs, European institutions, Universities from the US, UN Agencies and others. This shows the level of eﬀort it takes to get data in African towns and cities. This form of Urban Metabolism study conducted by these authors falls under what Ferrão and Fernández (2013, p. 80) call Substance Flow Analysis because it typically analyses the change in chemical composition of water (only one substance) starting from the point of entry up to the point of exit. 4 Ranzato et al. (2018b) This book is an outcome of a project named as ‘Local Capacity-Building for Sustainable Urban Development (authors of this of Small Regional Towns in Ethiopia: The Case of Amdework’ and ECIP Lab. It has an objective of mapping article are among the metabolism of 5 major ﬂows in and around the case town, Amdework. It is a brainchild of contributors and a collaborative research that involved two Belgian and one Ethiopian Universities and a donor – ARES. The editors of this book) publishing of this book is a huge success and a mile stone because it came up with a new bottom up approach to understand the metabolism of hidden ﬂows in the towns and cities of the developing world. However, the challenge of getting usable data was a major hurdle during the data collection and analysis stages. That is why some results of the metabolism (such as metabolism of housing materials) are expressed in the book only qualitatively. other interested parties. And, that is why scholars important. In addition, researchers decided to stick to such as Ferrão and Fernández (2013, p. 76) use this sample size because of the need to conduct an in- phrases like ‘Hidden Flows’ to describe such unac- depth investigation on few cases and generate reliable counted ﬂows. However, this research tries to shade data that can accurately represent the dominantly some light on these hidden ﬂows using estimations existing housing conditions in the town. and conversions where traditional builders, in addi- As canbeseenfrom Figure 1, tasks of character- tion to the home owners, were the major source of ising and quantifying ﬂowsofinputsused inthe data as they can better state the volume of materials construction the two dominant residential houses used during the construction. in Amdework have passed through diﬀerent steps. Data were collected from 20 houses (from two The characterisation and quantiﬁcation of the ﬁrst strata – 10 from Vernacular Stone houses and another groupofinputssuchascement, corrugatediron 10 from ‘Chika’ houses). The two strata are chosen sheets, nails and other industrial inputs was rela- because these two typologies, as discussed in Section tively easier because these inputs were already 4.1, make up 95% of the housing stock in the town. The labelled (measured) by the manufacturers using sample size is ﬁxed at this level because of the relative conventional units. The task of quantiﬁcation got internal uniformity of the sampling units within each abit diﬃcult when it came to the second group of stratum. It is the presence of local construction regula- inputs.Thisincludesinputssuchassand, stones, tions and traditional rules that determine the amount timber, soil, and other similar inputs. Data about and types of inputs used for residential house construc- the consumption of such inputs is available only tion that made the houses in the two strata internally partially because of the diﬃculty in measuring uniform. This uniformity makes a large sample size less them. Most of them are considered as less INTERNATIONAL JOURNAL OF URBAN SUSTAINABLE DEVELOPMENT 177 Process (Activity) Data Sources (Accuracy of data declines to the Right) Labeled Semi-Formally Informally (measured) Measured (by measured (by Assessing Data materials (inputs) traditional traditional Quality using Metric Builders and Builders and system home owners) home owners) Classification of Cement Stone Woods Housing Paints Sand Straw Materials Some Metals (like Soil Water nails and Some Metals corrugated iron Glass Timber sheets) What to do? Use it as it is Conversions and Estimations Data 3 3 Generated Weight in kg Volume in m Volume in m Data in Metric System What to do? Using it as it is Conversions to kg (using available tools) Data Acquisition Metabolism of Residential Housing Materials for a single average sized House in Amdework Extrapolating the Findings to the stock of residential Houses in the Town and beyond Interpreting the Result and linking it to the body of literatures Figure 1. Methodological Framework (Source: Authors, 2018). measurable by the local people or are measured (SankeyMATIC – the program used to generate the using customary units such as truck full of the spe- ﬂow diagrams). And ﬁnally, the most diﬃcult task in ciﬁc material, number of trips made to transport the the characterisation of the inputs was quantifying materials and etc. It, therefore, requires probing and the third group of inputs that are measured using furtherestimationtoget theexact ﬁgures even in traditional units such as bundles, heaps, number of terms of the traditional measurements. It then donkeys used to transport the inputs or the number requires one more additional step of converting of round-trips made by the people or animals to the volumes or the available units to conventional transport the items. The ﬁrst step adopted to quan- units to make the data usable by the program tify those inputs is, therefore, to get the exact 178 T. T. TOLA ET AL. amount consumed (in terms of the traditional mea- 3.2.1. A brief description of the town of surements) through probing and triangulation Amdework and the two dominant housing (because the inputs are diﬃcult to measure in the typologies ﬁrst place and averages were taken in cases where Amdework is a small town found in the northern part of traditional builders state diﬀering amounts). This Ethiopia. It is located in the Wag-Himra zone of the was then followed by conversion to conventional Amhara Regional State. It is the seat of a district called (metric) units through a careful measurement of Dehana Woreda. The district has a population of samples with the help of traditional builders and 129,572; out of which only 6,411 people live in the data collectors. town of Amdework. This puts the level of urbanisation These data, after conversion to the conventional in the district at 4.94%. Like all other towns and cities in units, were ﬁnally entered into SPSS software for clean- the country, this town is experiencing a rapid increase in ing and calculations of descriptive statistics that can be urban population. ([ANRS UPI] Amhara National used as inputs for the metabolism analyses. The map- Regional State Urban Planning Institute 2016; Dehana ping and modelling of the metabolic ﬂows and activ- Woreda Annual Report 2015). ities were then done using a freely available online tool ‘Chika’ Houses: Chika houses are almost similar to the called sankeyMATIC. ‘Wattle and Daub’ Houses. These houses use eucalyptus tree to form the structure of the wall and the roof. The wall is covered by a daub (fermented wet soil strength- 3.2. Scope of the study and context ened and stabilised with straws) and the roofs are cov- ered by thin corrugated iron sheets (see Figure 2 – right). Thematically, the research analyses the metabolism of Vernacular stone Houses: People in Amdework are construction materials of residential houses in the town known for their vernacular stone residential houses, of Amdework. It speciﬁcally focuses on the materials commonly known as the ‘Hidmo’ houses. The walls of used in the construction of two types of residential these ‘Hidmo’ houses are made of dressed stones joined houses; namely: the vernacular stone houses called together by a mud mixed with straw. The roofs of these ‘Hidmo’ and ‘Chika’ houses in the town. It analyses houses are of two types. The old ones have roofs made how the materials used in the construction move in of timber covered with tree leaves (or straws) and soil. the local and regional urban system. This traditional rooﬁng system, although has better Figure 2. Residential Housing Locations on the New Structural Plan of the town (left) and Satellite image of the town (right). (Sources: [ANRS UPI] Amhara National Regional State Urban Planning Institute 2016; Authors, 2018 and Satellite Image). INTERNATIONAL JOURNAL OF URBAN SUSTAINABLE DEVELOPMENT 179 cooling eﬀect, is prone to leakage and frequent col- typologies, generally, represent 95% of the housing lapses. Because of this, people have recently started stock in the town. covering their ‘Hidmo’ houses with thin corrugated In addition to the visible poor housing quality and iron sheets (see Figure 2 – left) existence of backlog, Table 2 indicates that large proportion of the houses in the town lack some essential housing elements that one gets in decent 4. Analysis and discussions houses. For instance, 75% of the houses in have earthen ﬂoors; and there are also many houses lack- 4.1. Housing in Amdework ing essential elements like kitchens and toilets. Shortage and dilapidation are some of the adjectives To curb the current shortage of housing, the town used in literatures to describe housing conditions in has recently started providing small plots of lands for towns and cities of developing countries. ([UN- residents who formed cooperatives and mobilised HABITAT] United Nations Human Settlements ﬁnance from their own sources and/or from a local Programme 2007 World Bank, Government of Micro Financial Institution named as ASCI. After Ethiopia, Cities Alliance 2015). Likewise, housing con- depositing an advance amount of 7000 birr in dition in Amdework is in a dire condition as the rest a blocked account, the city gives potential home of the developing world. [ANRS UPI] Amhara National builders, on average, 150 m plot of land per house- Regional State Urban Planning Institute (2016) indi- hold. A visit made to the construction sites reveals cates that the currently existing 1900 residential that, as also shown in Figures 2 and 3, most of the houses in the town falls short of the housing demand houses are modiﬁed vernacular ‘Chika’ houses of because there are more number of households than similar design. As can be seen from Figure 2, many the number of housing units in the town. As indi- of them are being constructed on crop lands along cated in Table 2, the town is already faced with many the expansion areas on the Southern, Southwestern challenges in supplying decent housing for its and Northern parts of the town. residents. Analysis made using satellite images indicates The dominant housing typologies, the ‘Chika’ that 444 ‘Chika’ houses have been constructed in houses, labeled as semi-vernacular in Davis (2012), the last three years alone on 9.22 ha of land. These account for 65.5% (1245 housing units) of the total houses have an average density of 48 houses per housing stock in the town. The second dominant hectare. These ﬁgures are important because they type is the traditional stone houses. These vernacular indicate the intensity of growth of the town (a stone houses account for 29.5% (560 housing units) 23.3% increase in housing stock only in three of the total housing stock in the town. These two years time). Another analysis made on the new structural plan of the town also indicates that the town has reserved 38.05 ha of land (which covers Table 2. Housing conditions in Amdework (source: [ANRS UPI] 14.04% of the town) for residential purpose for the Amhara National Regional State Urban Planning Institute 2016). following 10 years. Taking the density of 48 houses Number of houses Percentage per hectare, the town will host additional 1826 Walling Material Chika (Wood and 1245 65.5 houses in the remaining 8 years (which is the Mud) remaining life of the structural plan of the town). Stone 560 29.5 The Urban Metabolism analysis given below is, HCB 57 3 Bamboo 38 2 therefore, importanttooltoplanforthe amount Total 1900 100 inputs required for the construction of these Flooring Earthen ﬂoor 1425 75 houses. It also helps to plan for the reduction of material Cement screened 475 25 Total 1900 100 the environmental footprint of these construction Availability of Yes 1750 92.1 works. Figure 2 indicates the locations of the new Kitchen No 150 7.9 444 cooperative ‘Chika’ houses constructed in the Total 1900 100 Availability of Yes 1790 94.2 last three years. The satellite image on the right Toilet No 110 5.8 shows the relative location of these cooperative Total 1900 100 houses in the town. 180 T. T. TOLA ET AL. Regarding the usage of construction materials, indicates that the construction of these houses especially for walling, Table 2 indicates that Wood mainly relies on local materials which originate from and soil (for Chika houses) and stone (for vernacu- within the district boundary, except wood which lar stone houses) are the dominant ones. An inter- travels longer distance to reach the town. view made with the traditional builders (Personal Furthermore, as the town serves as the administra- Communication, 24 January 2017) indicates that tive and service center of the district, (the district the eucalyptus wood, used to build the structure includes the town itself and 34 rural Kebeles ) and of the wall, as shown in Figure 3,comes from since all residents of the district travel to the town on a place called Gayint, which is 330 km away from foot to access the market and all sorts of other Amdework. They also extract stone from very services, ([ANRS UPI] Amhara National Regional nearby quarries for the construction of vernacular State Urban Planning Institute 2016) this research stone houses and for the foundation works of the uses the district boundary as the main system ‘Chika” types. This reliance on distant source for boundary to analyse the metabolism of materials the major input for the construction of the ‘Chika’ used in the construction of residential houses in the househas animpact onthepriceof the material town. However, the boundary sometimes extends and also leaves a major carbon footprint on the beyond that following the ﬂow of essential inputs environment. of housing construction. 4.2.1. Metabolism of construction materials used 4.2. Metabolism of construction materials of the for an average sized common (47.2 m ) residential two dominant residential housing typologies house in Amdework Urban Metabolism is an essential tool to understand The construction of an average sized residential house the ﬂow of the construction materials into and out of in Amdework with an area of 47.2 m , regardless of its an urban system and its sub-systems. It is also pro- typology, relies on both imported and local materials. vides an important input for sustainable spatial plan- The import component of the inputs accounts for ning and design (Kennedy et al. 2010). The ﬁrst task 13.4%. These inputs come from areas outside local to understand the metabolism of housing construc- boundary, and the balance (86.6%) originates from tion materials was to deﬁne what the term local local sources. It is also evident that the outputs from means. The term local in this research stands for all these residential houses mainly stay within the local locations that fall within a walking distance from the boundary as most of them are reused or recycled by town and those areas from which the dominant the local residents. There are some portions that leave proportion of construction inputs originate. As will this boundary. Even those which leave the boundary be thoroughly discussed in the subsequent sub- may partly stay within the system. Some of the outputs sections, this study made on the metabolism of con- that fall in this category are the water used during struction materials used for the construction of local construction that is lost through evaporation and per- ‘Chika’ and traditional stone houses in the town colation; and the portion of wood and timber that Figure 3. Pictures of a traditional stone house (left) and a ‘Chika’ House (right) in Amdework (Source: Authors, 2018). INTERNATIONAL JOURNAL OF URBAN SUSTAINABLE DEVELOPMENT 181 residents use as a ﬁre wood after the end of the eco- recycled with no or minimum negative impact on nomic life of the residences. the environment. This clearly indicates the culture Other outputs such as stone and metals are mostly of circularity entrenched in the dominant housing recycled or reused for the construction of other houses construction methods in the area. or fences. On top of these, there are also local informal Furthermore, one can aggregate the ﬁgures in the collectors, as shown in Figure 5 (left), who buy these metabolism diagrams and estimate the amount of inputs scrap metals and sell it to other collectors who take it to used so far for the construction of residential houses metal factories in and around Addis Ababa for recy- (‘Chika’ and traditional stone houses that account for cling. Residents also reuse stronger woods reclaimed 95% of the total housing stock) in the town. from demolished houses for construction purposes. Accordingly, the two residential housing typologies in This is because of the price escalation observed in the the town have so far used 102,978,401.45 kg of inputs. construction sector, particularly because of shortage of This helps to understand the amount of already existing wood that comes from 330 km away from Amdework. stock of materials used to construct residential houses in The stone reclaimed from demolished houses is tem- the town. porarily stored in a nearby location (as shown in Figure 5 – middle and right) and will be reused for residential 4.2.2. Metabolism of construction materials of construction when the need arises. Studying the sour- average sized (58 m ) ‘Chika’ residential houses in cing of these inputs and the tendency of recycling it are Amdework important because the distance it travels determines Furthermore, another important ﬁnding about the issue the amount of energy embedded in it and the ecolo- of metabolism of construction materials of residential gical footprint it leaves behind on the environment. houses in Amdework is found by disaggregating the This is consistent with what is suggested in Smets and ﬂows depending on the housing typologies. ‘Chika’ Van Lindert (2016) who argued that sustainability in houses, which account for 65.5% of the residential hous- housing sector, especially in the Global South, can be ing stock in Amdework, secure 82.4% of their inputs improved by reducing the carbon footprints of the from local sources. The import component of the inputs construction process and by taking planning measures is 17.6% (see Figure 7). This is higher than the ﬁgures such as densiﬁcation. reported above as there is a slight increase in the import Another closer scrutiny made on the metabolism of component of the houses as compared with an average materials used in the construction of average sized house in the town. Chika houses with an average area of 2 2 (with an area of 47.2 m ) residential houses in 58 m use inputs that weigh 58,486.77 kg. This means Amdework reveals that these houses utilise 57,051.75 kg constructing 1 m of ‘Chika’ house consumes 1,008.39 kg of inputs. In terms of weight, stone inputs, which origi- of inputs (including water). nate from local sources and which are 100% reusable, The import component of ‘Chika’ houses is higher contribute 33.6% of all inputs. The second bulky mate- because it consumes more imported wood which, on rial used in the construction of these houses is water. average, weighs 8895.6 kg per housing unit. This This contributes 21.2% followed by soil and wood, accounts for 15.2% of total inputs and 86.4% of all which contribute 18.8% and 14%, respectively. Except imported inputs. In addition, these typologies consume wood, which mainly comes from far away (330 km), large amount of water as the preparation of the daub others originate from nearby (local)areas. This makes need to be wet and kept moist for about three weeks in them friendlier to the environment and the household order for the bacteria to develop and create an enzyme economy. that improves the consistency and density of the soil Another important information that can be making it suitable for walling (Davis 2012). drawn from Figures 4 and 6 is that 86% of the outputs do not end up in landﬁlls or other envir- 4.2.3. Metabolism of construction materials of onmentally unfriendly disposal systems. These con- average-sized (36.4 m ) traditional stone struction outputs are either reused, recycled, residential houses in Amdework evaporate or decompose naturally. Speciﬁcally, Vernacular stone houses, locally named as ‘Hidmo’,are the culture of reusing and recycling the outputs very common in and around Amdework. Although from demolished residential house is very encoura- people are abandoning these typologies in recent ging as 45% of all outputs are either reused or days due to diﬀerent reasons, as discussed below, 182 T. T. TOLA ET AL. Figure 4. Metabolism of construction materials for single average-sized house (Source: Authors, 2018). Figure 5. Pictures of informal metal collectors (left) and stone reclaimed from demolished houses stored nearby residences for future constructions (middle and right). (Source: Authors, 2018). these houses leave minimal carbon footprint on the Amdework. Metabolism diagram shown below (Figure environment because of their reliance on local materi- 8) indicate that these houses are composed of 3.4% als and indigenous knowledge. As indicated in [ANRS imported construction materials in terms of weight. UPI] Amhara National Regional State Urban Planning This is equivalent to 1,012,698.4 kg for the 560 houses. Institute (2016), currently there are 560 such houses in The local input component of these houses is 96.6%. INTERNATIONAL JOURNAL OF URBAN SUSTAINABLE DEVELOPMENT 183 Figure 6. Fate of construction materials for average sized residential house after the demolition of the houses (Source: Authors, 2018). This indicates that a very large proportion of the inputs collapsing and leaking roofs, used in the construction of ‘Hidmo’ vernacular stone longer period of construction, houses in Amdework are locally sourced. That is why it lack of attention from the government, and is argued that the carbon footprint of these houses is unfavourable local planning practices. minimal as compared to other typologies in the town. However, interview made with local builders indi- As shown in the metabolism diagrams, materials cates that there are many challenges that this construc- used in a typical vernacular stone housing in tion method is enduring in recent years (Davis 2012; Amdework, mainly stone and soil, which account Personal Communication, 25 January 2017). People are for 95% of the inputs, are either decomposable or abandoning these typologies because of: recyclable with the minimum or no adverse environ- mental impact. However, the sigma, as noted in the bulky nature of inputs it utilises, Davis (2012) or the abandonment as discussed in dissipating local knowledge of construction Foruzanmehr and Vellinga (2011) need to be evalu- methods, ated carefully so that these houses contribute for the 184 T. T. TOLA ET AL. Figure 7. Metabolism of construction materials of ‘Chika’ houses (Source: Authors, 2018). sustainable urbanisation in small towns of similar natural increase in population is the biggest contri- character in Ethiopia and beyond. butor to the growth at the current time; starting from 2018 the rural-urban migration will overtake it and becomes the major cause of urbanisation in Ethiopia. 4.3. Implication of the results on the national Figures mentioned in Table 3 are important to urbanisation estimate the amount of inputs required, at least, for the ‘Chika’ and ‘Stone’ houses to be built in the The level of urbanisation in Ethiopia is on the rise. Data towns and cities of Ethiopia in the coming from World Bank, Government of Ethiopia, Cities Alliance 20 years. However, it is important to make the (2015) indicate that only 22% of the total population of following assumptions to complete the estimations the country is urbanised by the year 2017. Although the (extrapolations) of inputs required for the construc- level of urbanisation is very low, the rate at which the tions of these houses for the newly arriving urban country is urbanising is very high. The rate of urbanisa- population in the coming decades. The assump- tion during the same year is 5.6%, and the rate will tions made to make the calculations are the remain above 5% for the coming two decades. following. It is indicated in Table 3 that there are diﬀerent causes of this rapid urbanisation in Ethiopia. These (1) These two typologies, the ‘Chika and ‘Stone’ are: Natural Increase; Rural-Urban Migration; New houses, as observed in Amdework, will make Town Formation; Urbanisation due to Government up 95% of the housing stock in similar emer- Built Mega Projects; and due to Redeﬁnition of ging small towns in the coming 20 years. Urban Boundaries (Urban Expansion). Although the INTERNATIONAL JOURNAL OF URBAN SUSTAINABLE DEVELOPMENT 185 Figure 8. Metabolism of construction materials of traditional stone house (Source: Authors, 2018). (2) These two typologies will still remain impor- two typologies in the subsequent years. The tant solutions to the housing demands of the lower middle income (which make up 5.3%, poor in medium and large cities in the coming according to [AfDB] African Development years. It is indicated in (World Bank, Bank 2011) are, therefore, assumed to go up Government of Ethiopia, Cities Alliance 2015) the ladder and join the upper middle income that there are large number of poor people in the second half of the 20 years (in the ﬁnal (25.7%) living under the poverty line in those 10 years) Hence, the proportion of people small towns and cities in Ethiopia. In addition, building these types are assumed to decline 18.5% of the urban residents fall in the cate- to 33.6% during the ﬁnal 10 years. gory of ﬂoating and lower middle income (3) The analysis does not include the housing groups ([AfDB] African Development Bank demand in rural areas that may be met by 2011) that may prefer these housing typolo- using similar materials or typologies (Chika gies because of aﬀordability. Hence, depend- and Stone) ing on these two ﬁgures, close to 38.9% of the (4) A one-to-one House to Household ratio is used new housing stocks, at least in the ﬁrst half of (5) An average household size of 3.8 is used ([CSA] the 20 years, are assumed to be built using Central Statistical Authority (Ethiopia) 2007) these materials. However, the declining trend in poverty and the increase in middle income Given the current urban population of 20,790,391, group may reduce the proportion of these which is expected to grow to 53,781,087 by the year 186 T. T. TOLA ET AL. 2037, the towns and cities across the country are informal sources of data, quantiﬁed and mapped the expected to prepare themselves for the additional ﬂows of housing materials in the case town in Northern 32.9 million urban population (see Table 3). This Ethiopia – Amdework. population, depending on the above table and the Although it was very challenging, the develop- assumptions, may require large amount of housing ment of this methodology, with traditional builders units in the coming years. Table 4 summarises the being at the heart of the data generation process, growth in urban population and the speciﬁc proved to be quite essential to understand and demand of the two housing typologies in the com- quantify the ﬂows of materials and activities ing 20 years. (related to housing) into and out of the town. Taking the data and assumptions given above, Developing such methods is crucial because it about 10.98 million of the 32.9 million new urban plays an important role in exploring the cost, residents will require 2.88 million new ‘Chika’ or resource eﬃciency, and ecological footprint of the ‘Stone’ houses in the coming 20 years (taking 3.8 as construction methods, which are crucial to the average household size). These houses, therefore, enhance the sustainability of low-income housing require large amount of inputs that are thoroughly in the towns and cities of the developing world in discussed in the previous sub-sections. Considering the coming years and decades. the material need of these new low cost housing Analysis made using this methodology also demands, it is imperative to devise methods that reveals that the majority of inputs used for the are resource eﬃcient and lower the carbon footprint construction of both typologies come from local of the housing productions in the coming decades, sources. However, a close scrutiny made on each as also discussed in Smets and Van Lindert (2016). typology separately reveals that there are some unsustainable ﬂows in the construction of ‘Chika’ houses in the town (like the sourcing of wood). In 5. Conclusion addition, it is found that people are stigmatising and are moving away from typical traditional Various activities, systems and sub-systems in urban houses (vernacular stone houses) which are more areas leave their hallmark on the environment and reliant on local materials and are known for leaving stock of resources. The construction of housing, an less environmental impact than other typologies. activity known for mobilising and consuming large Another important ﬁnding reveals that the pre- amount of bulky inputs, is one of those activities that sence of well-entrenched culture of reusing and need to be closely monitored to improve sustainability recycling construction inputs in the town signiﬁ- in urban areas. Urban Metabolism approach, in recent cantly reduces the proportion of waste of this sub- years, has become a potent tool to understand and system and its ecological footprint. quantify the impact of material ﬂows and activities on The ﬁndings are also extrapolated to the national sustainable urban development. This research, through level and the future (depending on the trend of devising a new bottom-up approach that relied on Table 3. Reasons of urbanisation in Ethiopia forecasted for 20 years (adapted from World Bank, Government of Ethiopia, Cities Alliance 2015). Years Cause of urbanisation 2017 2022 2027 2032 2037 Annual natural increase 429,061 501,292 577,490 652,440 821,449 Annual rural-urban migration 386,569 518,151 693,391 890,104 1,130,769 Annual new town formation 112,523 112,523 112,523 112,523 112,523 Annual urbanisation due to mega projects 72,994 185,000 185,000 185,000 185,000 Annual urbanisation due to expansion of urban areas 30,682 40,551 52,729 67,353 85,228 annual urban population increase 1,031,828 1,357,518 1,621,143 1,907,420 2,334,964 Urban population 20,790,391 26,751,671 34,183,609 42,996,773 53,781,087 National population 94,352,000 105,166,000 115,946,000 126,514,000 136,792,000 Percent of urban 22.0% 25.4% 29.5% 34% 39.3% Urbanisation growth rate 5.6% 5.4% 5.3% 5.2% 5.0% INTERNATIONAL JOURNAL OF URBAN SUSTAINABLE DEVELOPMENT 187 Table 4. Forecasting the housing demand of Chika and stone houses for the coming 20 years (World Bank, Government of Ethiopia, Cities Alliance 2015; [AfDB] African Development Bank 2011; Authors forecast, 2018). New urban population due to Total new Percentage of people who Total urban population that Housing units required New town Other urban demand Chika and Stone demands ‘Chika’ and ‘Stone’ (taking 3.8 household Years formation reasons Population Houses houses size) 2017–2022 562,615 5,398,664 5,961,279 38.9% 2,100,080 552,651 2023–2027 562,615 6,869,323 7,431,938 38.9% 2,672,167 703,202 2028–2023 562,615 8,250,550 8,813,165 33.6% 2,772,185 729,522 2033–2037 562,615 10,221,699 10,784,314 33.6% 3,434,491 903,813 Total 2,250,460 30,740,236 32,990,696 10,978,923 2,889,188 urbanisation and the changing economic conditions in topics ranging from urban metabolism, ecosystem services, circular economy, cities of the future, and energy to public the country) to estimate the amount of inputs required space, urban regeneration, and research by design. With 5 to construct similar low cost houses in the country in books and over 50 scientiﬁc publications, Prof. Khan is a fellow the coming years. of several learned societies, editorial board member and reviewer for many academic journals, and sits on the scientiﬁc review panels of European research funding agencies. He has Notes also practiced for about a decade, and regularly advises city and state governments on sustainable architecture and urban 1. Characteristics of these houses will be discussed in the development in Africa, Europe and South Asia. subsequent section. Fisseha Wegayehu is a fulltime professor at the Ethiopian 2. Woreda refers to a local administrative unit that is Institute of Architecture, Building Construction and City equivalent to a district which is composed of both Development (EiABC) at the Addis Ababa University. He urban and rural areas. obtained his PhD at Rice University, Houston, Texas, with a 3. Amhara National Regional State Urban Planning research on Ethiopian housing development. His research inter- Institute. ests are in Architecture and Urban/City Planning. Currently 4. Amhara Saving and Credit Institution. Fisseha is a lecturer, a director of Graduate Programs at the 5. Birr (commonly called Ethiopian Birr or ETB) is the EiABC. He also directs, Ethiopian Emerging Cities Laboratory Ethiopian Currency. Exchange rate on (ECiP Lab) launched by ARES project entitled as “Local Capacity- 28 December 2018 is €1 = 32.6 ETB. Building for Sustainable Urban Development of Small Regional 6. The smallest administrative unit below the district. Towns in Ethiopia: The Case of Amdework”. Professor Fisseha has many scientiﬁc publications and supervised several PhD & M.Sc. researches that focus on urban development. Disclosure statement No potential conﬂict of interest was reported by the authors. ORCID Notes on contributors Teshome Tefera Tola http://orcid.org/0000-0002-9727-9604 Teshome Tefera Tola is a full time Lecturer at the EiABC, Addis th Ababa University (AAU) in Ethiopia. Currently, he is a 4 year References PhD Student at the AAU and ULB in Belgium doing researches in the areas of urban metabolism and resilience. Teshome has [AfDB] African Development Bank. 2011. The middle of the participated in diﬀerent master plan, local development plan, Pyramid: dynamics of the middle class in Africa. Market environmental audit and impact assessment projects in diﬀer- Brief [Accessed 2018 February 18]. https://www.afdb.org/ ent towns and cities in Ethiopia. ﬁleadmin/uploads/afdb/Documents/Publications/The% Ahmed Z. Khan is Professor and Chair Sustainable Architecture 20Middle%20of%20the%20Pyramid_The%20Middle%20of% and Urban Design at the BATir department of ULB. 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International Journal of Urban Sustainable Development
– Taylor & Francis
Published: May 4, 2019
Keywords: Urban Metabolism; sustainable development; small town; carbon footprint; construction materials