Publications

ASIST Bulletin no. 10, January 2000

Counting the costs of developing Kampala's wetlands

By Lucy Emerton, IUCN – The World Conservation Union, Kenya

All too often environmental issues are ignored when cities are planned and built. Yet the state of the environment is not just a biological or ecological concern – when developments encroach on natural ecosystems or destroy environmental resources, they almost always give rise to immense social and economic costs. Not only do these costs often accrue to the poorest and most vulnerable sectors of the population, but they can also undermine the very aims of urban development itself – the better provision of services, the generation of income and employment, and the earning of government revenues. Below we ask the questions: just what are the economic costs of omitting environmental concerns from urban planning and development? Are they costs which either governments or urban populations are willing, or able, to bear over the long term?

One of the places where urban pressure on the environment is most acute is in Kampala District, Uganda. Over the last decade Uganda has entered a period of intense economic growth, infrastructural rehabilitation and urban development. Today nearly half of the country's urban dwellers live in Kampala, where the population is estimated to be increasing at an annual rate of nearly 5%, almost double the national average. To cope with this rapidly rising population, settlements are expanding, construction is taking place and urban infrastructure is being improved throughout the city.

Many of these developments have involved draining and reclaiming wetlands. Almost one sixth of Kampala District, or 31 km2, is covered by wetlands (‘wetlands' include permanent swamps and water bodies, as well as seasonally flooded areas), including some of the parts of the city that have been zoned as centres of development. These wetlands are, without exception, facing a serious threat of total destruction. It is estimated that about three-quarters have been affected significantly by human activity and about 14% are seriously degraded. By far the greatest threat to wetlands is their reclamation for industrial and housing development.

One wetland area in particular has been severely encroached upon by settlement and industry. Nakivubo is one of the largest wetlands in Kampala, covering almost 6 km2. It stretches from the central industrial district and passes through dense residential and commercial areas, before entering Lake Victoria at Murchison Bay. The areas around Nakivubo, including the wetland itself, are regarded as prime sites for urban development due to their proximity to the city centre and industrial district. This is as a result of land shortage in other areas, and because land prices are still relatively cheap as compared to other parts of the city.

There is a danger that Nakivubo may soon be modified and converted completely. Until recently, this has not been seen as a major problem by urban planners and civil engineers. Wetlands are generally seen as having little value, especially in the face of pressing needs for land for construction, and in comparison to the large and immediate profits these developments yield. Slowly, this perception is changing. The National Wetlands Programme of the Ministry of Water, Lands and Environment — the national government agency mandated with wetlands management in Uganda — has however recently started to work closely with city planners in order to assess the economic and social impacts of wetlands conversion and degradation. For one of the first times in Eastern Africa, attempts have been made to assess the economic value of maintaining wetlands in a well-functioning state, and to quantify the economic costs associated with their degradation and loss. The resulting information is beginning to give a more complete picture of the economic desirability — and long-term viability — of converting and modifying Nakivubo. It is becoming clear that, contrary to the dominant development imperative in Kampala, residential and industrial development in wetlands does not necessarily make good economic sense, and cannot be based only on consideration of immediate financial gain. These expectations of private profits have also to be balanced against the broader social and economic costs that arise from wetland degradation.

Socio-economic values

One of the most important values associated with Nakivubo is the role that it plays in assuring urban water quality in Kampala. Both the outflow of the only sewage treatment plant in the city, at Bugolobi, and — far more importantly, because over 90% of Kampala's population have no access to a piped sewage supply — the main drainage channel for the city, enter the top end of the wetland. Nakivubo functions as a buffer through which most of the city's industrial and urban wastewater passes before entering Murchison Bay. These wastewaters equate to the raw sewage from nearly half a million households (or half of the city's population). Close by, the domestic effluents of approximately 8,000 households who live in low cost settlements around the wetland and the largely untreated wastes of nearly a third of the enterprises in the city's industrial district are also discharged directly into Nakivubo.

Nakivubo physically, chemically and biologically removes nutrients and pollution from these wastewaters. Wetland plants such as papyrus, reeds and grasses remove phosphorus and nitrogen. Suspended solids, pollutants and pathogenic organisms accumulate and decompose in the wetland's bottom sediments. Effluents are diluted through density currents caused by the difference in temperatures between the wetland and the water in Murchison Bay. It is estimated that Nakivubo currently processes almost half the nitrogen and a quarter of the phosphorus which enters it; is effective in removing bacteria and microbes; and has the potential, if properly managed, to improve the quality of water entering Murchison Bay still further. These functions are extremely important — the purified water flowing out of the wetland enters Murchison Bay only about 3 kilometres from the intake to Gaba Water Works, which supplies all of the city's piped water. The wetland ensures that a substantial proportion of pollutants have been removed from the water which enters this intake.

Another set of vital benefits are provided by the natural resources found in Nakivubo. About a third of the wetland — mainly in its northern or upper part — is used by up to 500 farmers for cultivating yams, sugarcane and other crops. The water, sediments and fertile soils retained in the wetland enable this cultivation. Several hundred people are also involved in harvesting wetland resources, such as papyrus, grasses, reeds and clay. In total, nearly a tenth of the residents of the low cost settlements which surround Nakivubo engage in wetland-based resource utilisation activities. Many of these people lack access to other employment opportunities, or engage in only occasional and low-paid casual work. The wetland provides a significant supplement to local earnings, and forms the sole source of cash income for many of the poorest households.

Economic costs

All of these economic benefits — and by implication the economic costs associated with their loss — must be balanced against the potential profits accruing from wetland conversion and development. Nakivubo wetland saves the government of Uganda a considerable sum of money each year, and makes a substantial contribution to the local economy. Even deducting the costs of managing the wetland's waste treatment functions better so as to maximise its water purification potential (some US$ 250,000 a year), Nakivubo provides a much cheaper way of dealing with Kampala's wastewater than other, man-made, options. The infrastructure required to achieve a similar level of wastewater treatment would incur costs of over US$ 1 million a year in terms of extending sewage treatment facilities at Bugolobi, or nearly US$ 2 million a year in improving water treatment facilities at Gaba. As well as being cheaper, wetlands' natural ability to purify wastes is far simpler than artificial waste treatment and water purification facilities because it is based primarily on the use of human labour and on the use of simple earth channels to spread wastewater across the wetland. Wetland farming and resource utilisation also have a substantial economic value — about US$ 150,000 a year — and provide food and income for nearly a thousand of the poorest families in Kampala.

The case of Nakivubo illustrates that environmental resources and natural ecosystems are not just places of scientific interest. They comprise a stock of natural capital which, if managed wisely, can generate substantial economic benefits. It is clear that, for sites such as Kampala, the issue is not whether processes of industrialisation and urbanisation should take place — of course they should, because they form a key part of most developing countries' future economic growth, and generate obvious social and economic benefits. Rather, it is becoming increasingly obvious that it necessary to question the ways in which these developments are carried out, and especially how they are conceptualised, planned and implemented with environmental concerns in mind. While planners and decision-makers often remain unconvinced by purely biological or ecological arguments, the ability to demonstrate that environmental degradation gives rise to real monetary costs can provide a strong — and much needed — economic justification for taking environmental concerns into account in urban development.

Like Nakivubo, many other environmental resources and natural ecosystems have a high economic value. For example, as well as the obvious income and subsistence generated through the use of their component natural resources, forests provide vital water catchment protection services, and coastal vegetation and coral reefs play an important role in protecting shorelines and coastal settlements from storms and tidal surges. They often help to fill the gap between the level of basic goods and services that government is able to provide, and that which rapidly increasing urban populations require. Omitting environmental concerns from urban planning and development can give rise to untenable economic losses for some of the poorest sectors of the population. It can decrease social and economic welfare throughout cities' residents, and impose high economic costs on the public sector agencies that have the responsibility for providing basic services and assuring an acceptable standard of urban living. These groups are rarely in a position to bear such costs or expenditures.