Urban waste landfill planning and karstic groundwater resources in developing countries: the example of Lusaka (Zambia).

Lusaka, the capital city of Zambia with more than 2 million inhabitants, derives approximately 70 % of its water requirements from groundwater sourced in the underlying karstic Lusaka aquifer. This water resource is, therefore, extremely important for the future of the population. The characteristics of the aquifer and the shallow water table make the resource vulnerable, and in need of protection and monitoring. A joint project between the Geology Departments of the University of Cagliari and the School of Mines of the University of Zambia, to investigate the "Anthropogenic and natural processes in the Lusaka area leading to environmental degradation and their possible mitigation" was carried out in July 2001. The main objective of the study was to evaluate the extend of the present environmental degradation, assessing the vulnerability of the carbonatic aquifer and the degree of pollution of the groundwater and to make proposals to mitigate adverse environmental effects. Analysis of water samples collected by the project indicate some areas of concern, particularly with respect to the levels of ammonia, nitrates and some heavy metals. As groundwater quality and quantity are prerogatives for a healthy and sustainable society, the study offers guidelines for consideration by the local and national authorities. Uptake of these guidelines should result in a number of initiatives being taken, including: (a) closure or reclamation of existing waste dumps; (b) upgrading of existing waste dumps to controlled landfills; (c) establishing new urban waste landfills and plants in geo-environmentally suitable sites; (d) local waste management projects in all compounds (residential areas) to prevent and reduce haphazard waste dumping; (e) enlarging sewerage drainage systems to all compounds; (f) enforcing control on groundwater abstraction and pollution, and demarcation of zones of respect at existing drill holes; (g) providing the city with new water supplies from outside the Lusaka well-field; and (h) in increasing environmental education in schools and to all citizens.