Impacts on groundwater quality and water supply of the Epworth semi-formal settlement, Zimbabwe
Many developing countries experience rapid urbanization without rapid economic growth. This encourages rural to urban migration, but governments are rarely in a position to immediately service the burgeoning urban population. These trends have led to the development of informal or semiformal peri-urban settlements in the municipal areas of large cities in the developing world. This chapter presents an investigation of a semi-formal settlement as a diffuse pollution source. Epworth settlement, southeast of Harare, has characteristics of both formal and informal settlements. The settlement began developing an urban character in the 1970s and has grown and densified substantially during the past twenty years. This growth has not been accompanied by significant investments in water supply and sanitation infrastructure. A survey of water supply and sanitation practices was undertaken, and it was determined that close to half the residents use unprotected wells for water supply and over 90% use pit latrines. The problem is worst in the oldest parts of the settlement. A groundwater quality investigation was therefore undertaken in this ward. Shallow boreholes were drilled, groundwater sampled and chemical and microbiological analyses performed. The results revealed significant levels of contamination, particularly with regard to nitrates and coliform bacteria, and highest down flow in the wetland areas. Elevated levels of these parameters are most likely caused by the abundant pit latrines in Epworth, although urban agriculture could be a secondary factor influencing the nitrate levels. - Preventing further deterioration in groundwater quality requires major investment in piped sanitation. Unless this comes from central government, it will have to be self-financed and residents are unlikely to contribute to costs unless they have security of tenure. The most pragmatic short-term solution for water supply would be for the local authority to extend provision of a limited water supply, via communal taps, to be used for drinking purposes only.