Environmental Education Articles

Environmental Effects of Urban Sprawl in Swaziland

By: Wisdom M. Dlamini- Swaziland National Trust Commission

The rapid increase in urbanisation in Swaziland (3 to 5% per annum) has been fueled by rural-to-urban migration. Currently about 25% of the population lives in urban areas or peri-urban areas in the country. If rural-to-urban migration continues at this rate, it is expected that by the year 2030, approximately 70% of the total population will be living in urban or peri-urban areas. That migration is stimulated by the pull of presumably more desirable conditions in urban areas combined with the push of deteriorating conditions in rural areas combined with the push of deteriorating conditions in rural areas. Thus, migration is a function of the perceived difference in opportunities and quality of life between urban and rural areas, regardless of the reality. This has led to the development of unplanned settlements with low quality housing, poor sanitation and unhealthy living conditions and shortage of job opportunities. This has resulted in a significant decrease in the provision of basic services of housing, water, sanitation, education and health services.

Urban areas exert demands on the environment for the disposal of residuals (waste) from activities in urban areas and for inputs into the activities in urban areas, e.g. food, fuel, land. The environmental effects of the former occur within the urban area. The off-site environmental effects can occur very long distances away, as a result of transport processes in the atmosphere and in water bodies. Residuals are generated and discharged within urban areas by all types of activities, e.g. residential, commercial, institutional, industrial, agricultural , transportation, and by the urban area as a whole in the form of storm runoff. The effects on ambient environmental quality resulting from the discharges are a function of the types and quantities of residuals discharged; the time pattern of discharges, i.e. daily, weekly or seasonally; the topographic setting; and the meteorological and hydrologic conditions. Examples of sources, residuals discharged and effects can be seen in Manzini where the problem of urbanisation is serious.

The built environment of urban areas transforms the natural environment into impermeable areas that preclude infiltration of precipitation. For the same distribution of rainfall, the increase in impermeability increases the magnitude and frequency of flood flows, increases discharges of suspended sediment and dissolved constituents into water bodies, changes the time pattern and water quality characteristics of streams within the urban area. In many of the cities and towns in the country, storm runoff is a major contributor to discharges to water courses and, hence, to deterioration of ambient water quality. The adverse environmental effects of urban storm runoff are exacerbated by inadequate management of solid wastes, with the resulting heavy litter, septic tank overflows and garbage in street gutters available for transport by the increased runoff. This is the garbage that ends up in rivers and threatens the lives of downstream users and also the animals and plants downstream.

Increased transport systems in most urban areas result in proliferation of thousands of private vehicles, which- as with the vehicles of public transport systems- typically have nom devices to reduce gaseous discharges to the atmosphere. A lack of maintenance of vehicles and the operation of vehicles until they fall apart results in high unit emission coefficients. Typically, there are still no vehicle emission standards . These characteristics of vehicle fleets in combination with traffic congestion result in high concentrations of particulates, carbon monoxide, and hydro-carbons within urban areas.

Residential, commercial, industrial , and institutional activities discharge gaseous residuals- particulates, sulphur oxides, and metals- into the atmospheres of urban areas following fuel combustion for space heating, process steam, energy generation, cooking, and burning of waste at the landfills. Various industrial and institutional activities discharge oils and grease, organic materials, synthetic organic compounds, and heavy metals in liquid waste to water courses. Either singly or in combination, organic materials, oils , grease, and some chemicals can reduce dissolve oxygen in water to zero, thereby virtually eliminating aquatic life. Deteriorated water quality affects in-stream uses such as recreation as well as withdrawal uses such as irrigation and water supply , thereby imposing additional costs for intake water treatment before use. Suspended sediment discharged into the water bodies from urban areas typically results in sedimentation downstream. This is a result of poor drainage design and construction.

Our two main cities, Manzini and Mbabane, are situated within the vicinity of rivers and this has resulted in discharges of various liquid, solid, and gaseous residuals.

The provision of infrastructure services, e.g. water supply, sewerage, and solid waste management, is inefficient. Poor construction of water supply distribution systems results in large leaks, which means that more materials and energy are required for the same level of service provided. Inadequate construction and management of landfills results in leaching chemicals into ground water and neighbouring streams and rivers. This can be observed in the landfill in Manzini which is situated not far from the Mzimnene river. It is unsightly situated and poses a threat to the health of the residents nearby.

Results of population concentration in our areas

An improved understanding is needed of the management of the natural resource base and the environment that supports urban economies if a government pursues a sustainable development program. Achievement of this is only if the city and its environment are treated as a system. The primary components of the urban system are its population, defined in terms of its size, density, growth rate, and relative heterogeneity; its natural environment or ecosystem; its built environment, particularly its infrastructure and overall land use pattern; its economy, most notably its underlying economic activity and the resource flows which support it; and its institutions, including governmental structure and policy making processes. It is the understanding and management of the interaction of these components that offers the most promise for the ability to minimise environmental damage. For example, when demand for land for housing exceeds supply and when institutions are unable to control or direct urban land use, the result is often unplanned settlements of environmentally sensitive areas, such as the hillsides of kaKhoza, Mangwaneni, New Village and other areas around Manzini and Mbabane. This, obviously has long-term development costs.

The following five guiding principles, accompanied by commitment and determination, can lead to a safe, healthy and beautiful city.

• Enhance urban economic growth. Urban growth, environmental protection, and sustainable economic development are inextricably linked. For development to be sustainable, the natural resource base must be protected.
• Develop strong institutions. Strong local governments and related urban institutions (city/town councils) must exist whose boundaries and jurisdictions correspond to the management tasks before them, including those of environmental management.
• Create better guidance for decision making. Government needs a systematic means of guiding urban investments to assure that scarce resources are used their maximum benefit in way that protects the environment and economic growth. This implies that environmental management be integrated with urban planning.
• Direct urban growth with land delivery and infrastructure investment. Market-driven, environmentally sound land delivery and well-conceived capital investments in infrastructure provide important opportunities for minimising pollution, reducing long-term development costs, and shaping the urban environment.
• Encourage private initiative. The private sector has a significant role to play in environmental protection, in its direct response to environmental concerns and as a provider of urban infrastructure, services and employment and investment related to pollution control.

Therefore, every citizen of the country must avoid this urban sprawl because, after all, the ‘migrants ’ are the victims of this problem.

References

World Resources Institute, World Resources 1998-99- A Guide to the Global Environment (1998), UNDP, UNEP, WRI and the World Bank, Oxford University Press.

Swaziland Environment Authority. Swaziland Environment Action Plan (1997) Vol.1

Environmental Education Articles