Assessing the impact of municipal wastewater discharge on streamflow and surface water quality in South Africa

The sustainability of water resources is fundamental in building a strong and resilient society. However, these resources have been threatened over the last decades due to natural and anthropogenic hazards. This study used both quantitative and qualitative methods to estimate, predict, and analyze the impact of wastewater discharge on surface water quality. The findings indicate that all the water quality indices were below 40% classified as very poor. Under low flow conditions, the highest wastewater contribution to stream flow (83%) was recorded at Renoster@bishop, while the lowest (23%) was at Renoster@Shanno. Furthermore, wastewater contribution to streamflow was analysed. The number of wastewater treatment plants discharging into the stream primarily influenced these contributions. Stakeholder perception on water quality degradation attributed to wastewater discharge was done through key informant interview and stakeholder engagement. Ensuring the proper treatment and disposal of wastewater remains the most effective approach to limit freshwater pollution.