Arid Lands Newsletter--link to home page No. 42, Fall/Winter 1997
Urban Agriculture in Drylands

Drought mitigation policy and food provision for urban Africa: Potential use of treated wastewater and solar energy

by Hendrik J. Bruins

"Africa south of the Sahara is the only part of the world where per-capita food production has fallen during the past decade....[This and other] trends help explain the expansion of urban food production throughout the region."

--Cities feeding people: An examination of urban agriculture in East Africa,
p. viii

Editor's Note: This article is a slightly revised version of a paper that was originally submitted to the workshop titled "Market Gardening, Farm Associations, and Food Provision in Urban and Peri-urban Africa," held in Netanya, Israel, on June 23-28, 1996. The workshop was sponsored by the Netherlands-Israel Development Research Programme (NIRP); additional contributors were Bar-Ilan University, Mashav (the International Cooperation Dept., Israeli Ministry of Foreign Affairs), and CINADCO (the Development Corporation branch of the Israeli Ministry of Agriculture). Proceedings of the Netanya workshop will be published, but there is no definite publication date yet. For more information on the Netanya workshop or on the workshop proceedings, contact:

Dr. David Grossman
Department of Geography
Bar-Ilan University
Ramat-Gan 52900

Drought And Urban Farming

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Severe droughts are recurring phenomena in many parts of Africa (Garcia and Escudero 1982; Glantz 1987; Akong'a and Downing 1988; Downing, Kangethe and Karnau 1989). Their impact on different segments of society varies with respective vulnerability and the success or failure of coping mechanisms at both the household and national level, including social and economic networks, food reserves, water reserves, financial reserves, food imports, food distribution, food availability, marketing and prices. However, the relationship between drought and famine is not straightforward. The causes for famines and food crises (Bohle et al. 1991, 1993; Cannon 1991; Downing 1993) are usually complex and cannot merely be explained in environmental terms. Drought, on the other hand, may still be the major actor on the crowded stage to cause or trigger famine. Without discounting all the other complex socio-economic and political factors, it may be said that famine in the Sahel during the late sixties and seventies would have been considerably less severe without environmental drought. The phenomenon of drought may be regarded as the most complex and least understood of natural hazards (Wilhite 1993). Proactive planning for drought (Wilhite and Easterling 1987; Wilhite 1993; Bruins 1993, 1996; Bruins and Lithwick 1997) on a national, local and household level is far better than ad hoc crisis management.

In a monograph about urban farming in Africa, particularly related to Kampala (Uganda), the significance of drought was emphasized by Maxwell and Zziwa (1992) in their introduction:

"The 1980s have been referred to repeatedly as a decade of crisis for African development. None of the factors underlying this 'crisis' are new: declining terms of trade, declining per capita production of food crops, increasing foreign indebtedness, environmental degradation and continued high rates of migration by the young from rural to urban areas. But combined with two catastrophic droughts through much of sub-Saharan Africa and the conflicts and political turmoil of the decade, the 1980s have witnessed the collapse of much of the formal, modern sector of Africa's economy, with a resulting decline in the standard of living for both urban and rural people. The droughts in particular provided the media with the necessary imagery to depict Africa as a continent in crisis." (page 1)

At the macro-level Maxwell and Zziwa (1992) mention the fundamental problem of annual urban population increases of up to 8%, almost twice as high as the population increase in general, and the inability of urban economies to absorb the increase. They suspect urban living standards to have suffered greater losses than rural living standards in relative terms. Poor people in the cities are constantly faced with the problem of how to survive at the household or micro-level amidst economic decline and the lack of job opportunities:

"Rather than return to the countryside, much of this urban population has resorted to any means at their disposal to survive in the city. The various survival mechanisms of the urban poor have come to be called the 'informal sector', so named by the International Labour Organization's investigation of employment conditions in African economies in the 1970s." (Maxwell and Zziwa 1992; page 2)

Urban agricultural production is often included in the informal sector, because cultivation and livestock rearing within urban sectors were generally forbidden during the colonial period. This hostile attitude by the authorities toward urban farming has usually continued after independence. Nevertheless, urban agriculture has been an integral part of African cities from the beginning of their development, as pointed out by Rakodi (1988). This fits also well with the perception of urban migrants, who view the city as their farm (Aronson 1978), as it becomes part of their extended geographic sphere, while the rural home often remains home, despite their living in the city.

Three fundamental observations concerning urban agriculture are noted by Maxwell and Zziwa (1992):

  1. Urban agriculture is an important component of household survival strategies for the urban poor.
  2. Urban agriculture has provided livelihoods and food to an increasing number of urban and peri-urban residents.
  3. Urban and peri-urban agriculture has a potential to provide productive jobs for the urban unemployed, while contributing significantly to the food provision of Africa's cities.

Drought, Urban Wastewater and Solar Energy

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The combined effect of increasing population size and shrinking land availability demands increased food production per capita. This can only be achieved through a more intensive management of resources in all aspects of food production. Urban and peri-urban agriculture should be included in such an approach, to be encouraged and guided by the authorities (Mbiba 1996). Agriculture requires water, which may be obtained directly from rainfall (rainfed farming), or indirectly from a variety of sources such as rivers and streams, wells, rainwater harvesting (Bruins et al. 1986), piped water and treated wastewater (irrigated farming). The occurrence of severe drought will undoubtedly cause a decrease in the level of food production under rainfed agriculture. The resultant decline in locally produced food needs to be compensated for, frequently by supply from existing reserves or imports, in order to maintain food availability and consumption at a secure level.

On the other hand, one of the characteristic aspects of urban development is the widespread availability of piped water, a sewage system and the resultant production of urban wastewater. Because water is in the short run even more critical than food for human survival, governments have usually planned to maintain the piped water supplies to cities from secure water resources which can be used even during times of drought. Hence the output of urban wastewater will also continue during meteorological drought. This rather stable production of urban wastwater should be perceived by planners as a real asset not to be wasted!

Four reasons can be given for the importance of urban wastewater treatment and purification in Africa:

  1. Urban wastewater needs to be contained and purified for reasons of public health.
  2. Raw urban sewage should not be permitted to flow freely on the surface, polluting streams, surface water and groundwater resources.
  3. Treated wastewater can be used successfully and safely, at or near its urban source, in urban and peri-urban farming to produce food without the need for chemical fertilizers.
  4. Urban wastewater will even be available during periods of drought, enabling urban and peri-urban food production to continue and thereby increasing urban food security.

Since urban sewage treatment requires government planning and supervision, it seems reasonable to suggest the need for agricultural extension education, legislation, and supervision concerning the agricultural use of the treated wastewater by individual urban farmers, in view of possible health hazards. However, a detailed World Bank report about wastewater irrigation in developing countries (Shuval et al. 1986), concluded that public health positions have often been overly conservative. The report recommends the use of low-cost stabilization ponds, considered to be a robust method of wastewater treatment well suited to the needs of developing countries. In fact, as we have already pointed out, 20-day stabilization ponds can remove almost all bacteria and viruses and can produce an affluent suitable for unrestricted irrigation of vegetables" (Shuval et al. 1986).

Solar energy is a potential source of energy that can be used independently by an individual urban farmer to power water pumps for irrigation. The cost of photovoltaic power is steadily decreasing (Oppenheim 1996), although its use by the urban poor would probably require initial investment capital from external sources and additional education by extension services.

Centralized development of urban wastewater treatment facilities by the authorities is certainly most desirable. However, solar energy could enable small-scale water disinfection from small streams, which might be polluted, and small-scale toilet and wastewater treatment facilities (Cobb 1996) for use by small communities in self-help projects. For example, in one solar water disinfection system, water from a stream, pond or community water supply flows into a tank with a capacity of 200 liters. Cold water at the bottom flows into a low-pressure solar hot water heater, in which the water is heated to 70 degrees C and is thus pasteurized. Grey water and brown wastewater (from kitchen and toilet) can be pasteurized with a similar system of solar heating in a composting toilet, such as the so-called SOLatrine, as described by Cobb (1996).

Solar disinfection of drinking water (Anderson and Collier 1996) can also make an important contribution to family and community health in areas where safe potable water is not available. Such solar systems can be set up on a small scale through private initiative by individual families or small communities. Infected drinking water causes death to an estimated 15 to 20 million children per year through diarrheal diseases. Anderson and Collier (1996) emphasize that heat is one of the most effective methods to disinfect drinking water. There is no need to boil water for 10 minutes, as tests have shown that all waterborne enteric pathogens are instantly inactivated at temperatures above 90 degrees C (Backer 1989). The system designed and tested by Anderson and Collier (1996) uses a parabolic trough solar concentrator to heat water in a receiver. A standard automotive thermostat at the end of the receiver ensures that water will not exit the system until it has reached the required temperature. A system of ca. 55 m2 of aperture, costing about US$3,300, would produce some 6,000 liters of disinfected water daily.

A much cheaper system to pasteurize drinking water and prepare food for a single person or family is the solar cooker. A new design by Solar Cookers International, the solar panel cooker, costs only US$10 and is also produced in Nairobi, Kenya. As of January 1997, more than 3,000 families had learned to use these solar cookers in the large refugee camp at Kakuma in northwestern Kenya.

Participatory Development

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The informal private sector of urban and peri-urban farming should not be taken over by the government, although the treatment of urban wastewater and its subsequent use in urban agriculture does require government planning, investment and extension services. Participatory development in urban and peri-urban farming may enable proper integration between central planning of wastewater treatment and its use by private farmers. Special legislation for use of urban and peri-urban for farming purposes should be made as flexible as possible. Municipalities in The Netherlands, for example, allow certain municipal areas, divided in small plots, to be farmed by interested individuals without their becoming owners of the land. Temporary permits are given and a small yearly fee has to be paid. Yearly extension of such permits in urban and peri-urban Africa could be made conditional on proper use of the wastewater and compliance with public health requirements.

Possible development relationships of constituent elements in urban and peri-urban food production are displayed in the accompanying flow-chart diagram (Figure 1).

Food Reserves, Food Security and Food Provision

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Drought usually causes a straightforward environmentally deterministic decline in food production based on rainfed farming. However, drought does not necessarily cause famine conditions. The latter depends on many complex socio-economic factors which prohibit a simplistic deterministic approach. Food production based on irrigated farming related to a relatively secure water supply, such as treated urban wastewater, can continue during drought. Nevertheless, the decline in food production from the rainfed sector needs to be compensated for by other sources. National food reserves would enable additional supply on the macro level. Such food stocks give national food security even if food availability on the world market is critically low. However, sufficient food reserves on the national level do not guarantee food security on the micro or household level. For example, the urban poor may be unable to pay for the supplies from national food stocks if the food prices are too high in relation to their purchasing power. Thus vulnerability to famine differs in society in relation to economic status. Bloody food riots have occurred in Africa, Asia and Latin America as a result of sudden increases of food prices, advocated by the International Monetary Fund to remove subsidies in the name of economic realism (Garcia and Spitz 1986).

Moreover, national food reserves mean nothing if the food is not equally distributed throughout the country and made available to the population at affordable prices. This underscores the relevance of food reserves, if possible, at the micro or household level. For much of the urban population, the practice of urban agriculture would appear to be a useful strategy for helping to increase such reserves.


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The relationships between drought, food production, food reserves, food security and food provision are complex and need to be understood on a case-by-case basis to improve existing situations. Urban farming has been taken up by the urban poor as a survival strategy, and more food is being produced in the urban and peri-urban sphere as a result. Encouragement and enlargement of such private enterprise by the authorities through the organized and proper use of treated urban wastewater could benefit both the urban poor at the micro and household level and the urban food situation at the macro level. In addition, solar energy has significant potential for small-scale powering of water pumps for irrigation, water disinfection for safe drinking water and even sanitary systems that may provide safe water for irrigating food gardens.


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Anderson, R. and K. Collier. 1996. Solar water disinfection. In Proceedings of the 1996 Annual Conference, ed. R. Campbell-Howe and B. Wilkins-Crowder, 184-188. Boulder, Colo.: American Solar Energy Society.

Aronson, D.R. 1978. The city is our farm. Cambridge, Mass: Schenkman Publishing Company.

Akong'a, J.J. and T.E. Downing. 1988. Smallholder vulnerability and response to drought. In The impact of climatic variations on agriculture. Volume 2, Assessments in semi-arid regions, ed. M.L. Parry, T.R. Carter and N.T. Konijn, 221-247. Dordrecht: Kluwer Academic Publishers/IIASA/UNEP.

Berkofsky, L. and M.G. Wurtele, eds. 1987. Progress in desert research. Totowa, N.J., U.S.A.: Rowman & Littlefield.

Bohle, H.G, T. Cannon, G. Hugo, and F.N. Ibrahim, eds. 1991. Famine and food security in Africa and Asia. Bayreuth: University of Bayreuth.

Bohle, H.G, T.E. Downing, J.O. Field, and F.N. Ibrahim, eds. 1993. Coping with vulnerability and criticality. Saarbruecken: Breitenbach Publishers.

Bruins, H.J., M. Evenari and U. Nessler. 1986. Rainwater-harvesting agriculture for food production in arid zones: The challenge of the African famine. Applied Geography 6:13-32.

Bruins, H.J. 1993. Drought risk and water management in Israel: Planning for the future. In Drought assessment, management and planning: Theory and case studies, ed. D.A. Wilhite, 133-155. Dordrecht: Kluwer Academic Publishers.

Bruins, H.J. 1996. A rationale for drought contingency planning in Israel. In The mosaic of Israeli geography, ed. Y. Gradus and G. Lipshitz, 345-353. Beersheva: Ben-Gurion University of the Negev Press.

Bruins, H.J. and H. Lithwick. 1997. Proactive planning and interactive management in arid frontier development. In The arid frontier: Interactive management of environment and development, ed. H.J. Bruins and H. Lithwick. Boston/Dordrecht/London: Kluwer Academic Publishers.

Campbell-Howe, R and B. Wilkins-Crowder, eds. 1996. Proceedings of the 1996 annual conference. Boulder, Colo.: American Solar Energy Society (2400 Central Avenue, Suite G-1, Boulder, Colorado 80301, USA).

Cannon, T. 1991. Hunger and famine: Using a food system's model to analyse vulnerability. In Famine and food security in Africa and Asia, ed. H.G. Bohle, T. Cannon, G. Hugo, and F.N. Ibrahim, 291-312. Bayreuth: University of Bayreuth.

Cobb, J.C. 1996. Solar sanitary system (SOL-SAN). In Proceedings of the 1996 Annual Conference, ed. R. Campbell-Howe and B. Wilkins-Crowder, 167-172. Boulder, Colo: American Solar Energy Society.

Downing, T.E. 1993. Concepts of vulnerability to hunger and applications for monitoring famine in Africa. In Coping with vulnerability and criticality, ed. H.G. Bohle, T.E. Downing, J.O. Field and F.N. Ibrahim, 205-259. Saarbruecken: Breitenbach Publishers.

Downing, T.E., W. Kangethe, and C. Karnau. 1989. Coping with drought in Kenya: National and local strategies. USA: Lynne Rienner.

Garcia, R.V. and J. C. Escudero. 1982. Drought and man. Vol.2, The constant catastrophe: Malnutrition, famines and drought. Oxford: Pergamon Press.

Garcia, R.V. and P. Spitz. 1986. Drought and man. Vol.3, The roots of catastrophe. Oxford: Pergamon Press.

Glantz, M H., ed. 1987. Drought and hunger in Africa. Cambridge: Cambridge University Press.

Maxwell, D. and S. Zziwa. 1992. Urban farming in Africa: The case of Kampala, Uganda. Nairobi: ACTS Press, African Centre for Technology Studies.

Mbiba, B. 1996. Urban agriculture in southern and eastern Africa: Policy questions and challenges. Paper presented at workshop, Market Gardening, Farm Associations, and Food Provision in Urban and Peri-urban Africa, 23-28 June, at Netanya, Israel.

Oppenheim, J. 1996. Photovoltaic economics: Cost-effective for some choosing least-cost power in the marketplace. In Proceedings of the 1996 Annual Conference, eds. R. Campbell-Howe and B. Wilkins-Crowder, 321-326. Boulder, Colo.: American Solar Energy Society.

Rakodi, C. 1988. Urban agriculture: Research questions and Zambian evidence. Journal of Modern African Studies 26:495-515.

Shuval, H.I., A. Adin, B. Fattal, E Rawitz, and P.Yekutiel. 1986. Wastewater irrigation in developing countries: Health effects and technical solutions. World Bank Technical Paper 51. Washington, D.C.: The World Bank.

Wilhite, D.A., ed. 1993. Drought Assessment, management and planning: Theory and case studies. Dordrecht: Kluwer Academic Publishers.

Wilhite and Easterling. 1987. Planning for drought: Toward a reduction of societal vulnerability. Boulder, Colo.: Westview Press.

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Author Information

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Dr. Hendrik J. Bruins is a faculty member of Ben-Gurion University of the Negev, where he is active in different departments: He has a joint appointment with the Jacob Blaustein Institute for Desert Research (Social Studies Center) and the Department of Geography and Environmental Development, and he is a research fellow at the Negev Center for Regional Development. You can contact him at:

Ben-Gurion University of the Negev
Jacob Blaustein Institute for Desert Research
Social Studies Center
Sede Boker Campus 84990
Tel: +972 (7) 659 6863
Fax: +972 (7) 659 6867

Additional Web Resources

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The Solar Cooking Archive
This outstanding web site is a wonderful resource for anyone interested in learning more about solar cooking. Numerous clearly illustrated plans for inexpensive solar cookers are available for downloading (including the plan for the $10 solar cooker referred to in this article). In addition, the site contains news on solar cooking activities around the world; pictures; a directory of solar cooker promoters, organizations and manufacturers; and lots of information on further resources. The site is searchable and accessible by text browsers. The Solar Cooking Archive is sponsored by:

Solar Cookers International
1919 21st St., Suite 101
Sacramento, CA 95814

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