SADC-GMI embarked on a project to investigate and provide management strategies for groundwater Dependency and Vulnerability in the Megacities of Luanda, Johannesburg and Kinshasa in the SADC region. These megacities face significant issues related to groundwater dependency and vulnerability due to their size, rapid urbanization, and environmental factors. To start with, rapid population growth and urban expansion strain water resources, leading to increased groundwater demand. Moreover, the impacts of climate change led to changing precipitation patterns, temperature increases, and sea-level rise which affect groundwater recharge rates and quality. Effective groundwater management in many megacities is hindered by inadequate governance, regulatory frameworks and institutional capacity. While urban pollution from industrial activities, agriculture and inadequate sanitation facilities poses significant threats to groundwater quality. Therefore, this study aims to generate an understanding of the Dependency and Vulnerability in the selected Megacities in the SADC region.

The overall objective is to determine the dependency and vulnerability of groundwater in the Megacities of Johannesburg, Kinshasa and Luanda. The study will encompass site visits and stakeholder consultation for data collection and issue identification. A comprehensive assessment of groundwater availability, recharge rates and aquifer characteristics will be conducted for each megacity to understand the quantity and quality of available groundwater resources in order to assess the dependency and potential risks. The current and projected water demand trends will be analysed considering population growth, industrial activities and agricultural need while also considering potential climate change impacts on future groundwater demand. Vulnerable areas that are prone to groundwater depletion, contamination and saltwater intrusion will also be mapped to identify high risk area and priority intervention to mitigating vulnerabilities. Following this, conjunctive management strategic action plans will be developed for each one of the 3 Megacities. The strategic action plans will provide frameworks to guide sustainable groundwater use, promote conjunctive of the resources in the Megacities, guide management mitigating risks and enhancing resilience to climate change and environmental stresses in mega cities.

The level of dependency varies across the megacities. Luanda faces escalating water security challenges which are fuelled by rapid urbanization, population growth. The city’s water supply system utilises surface water from the Bengo and Kwanza Rivers, however limited access to piped water, particularly in expanding peri-urban and informal settlements, has led to a growing dependency on other alternative sources like groundwater. Even though groundwater is not incorporated in the city’s supply, there are various area where groundwater in the predominant source for domestic purpose groundwater recharge is heavily influenced by land-use changes, where rapid urbanization alters infiltration dynamics, reducing available groundwater for dependent communities

Rapid urbanization and population growth in the megacities of Luanda, Kinshasa, and Johannesburg has placed immense pressure on their groundwater resources. These cities are increasingly vulnerable to contamination due to unregulated urban expansion and poor infrastructure planning. For example, in Johannesburg, the main aquifer is threatened by contamination from acid mine drainage (AMD), old mine dumps, and the release of partially treated sewage wastewater with pollutants migrating from distant sites via connected watercourses. Similarly, in Kinshasa. In Luanda sea water intrusion poses a significant threat to coastal zone aquifers. Inadequate sanitation infrastructure and uncontrolled urban sprawl have resulted in potential contamination into the aquifers in many peri-urban and informal settlement where pit latrines are and septic tanks are often constructed near shallow aquifers. Over abstraction in some aquifers has also introduced saline water in area such as Talatona. Even though inland aquifers like the Quelo aquifer also experience elevated salinity due to low aquifer permeability and prolonged groundwater residence times.