Protection of a shallow karst aquifer in Zambia – Approach and challenges

BGR and the Zambian government jointly develop and protect the groundwater resources in the country’s capital Lusaka. As one of the fastest growing cities in southern Africa, Lusaka has been facing a sharp increase in the demand for water in recent years.

Sustainable abstraction of groundwater and the protection of the vulnerable karst aquifer supplying Lusaka are two key elements for future urban planning in the face of population growth, annual outbreaks of waterborne diseases and climate change. Geoscientific experts have to ensure that decisions are based on scientific results and technical recommendations and that the importance of protecting the natural resource is being communicated as a priority to the government, industries and society.

Potential new well fields were identified and one objective of the BGR project is the delineation of groundwater protection zones as a case study for Zambia. The development of statutory instruments to make groundwater protection an integral part of the Zambian law secures the resources for the future. The delineation of the zones is based on the approach from Botswana, as the various Western approaches cannot simply be transferred to southern Africa as soil structure, geology, climate and urban areas are often drastically different.

Protecting a karst aquifer with a thin soil cover is scientifically challenging. The population growth and limited urban planning structures combined with insufficient data increase the risk of groundwater contamination in Lusaka. A high level of cooperation between geoscientists, decision-makers, environmental regulators and the society is required to face the various challenges.