Knysna Estuary health in the spotlight

A plan to address pollution of the Knysna Estuary was presented at a recent Planning & Development Committee meeting. Acting Municipal Manager, Dr Louis Scheepers said they appointed GroundTruth Water, Wetlands and Environmental Engineering in 2018 to do a wetland inventory and assessment within a 25km radius of the Knysna & Swartvlei estuaries.

“From the assessment it was clear that the Bongani River and associated wetlands were the main sources of contamination of the Knysna estuary. GroundTruth was asked to identify and assess freshwater ecosystems associated with the Bongani River catchment and to develop a rehabilitation plan to enhance the ecological functioning and processes of the system.”

He said the proposed rehabilitation plan includes earthworks, concrete weirs, geocell chutes (concrete structures used to slow down flow, prevent further headcuts and trap suspended solids) and concrete sill and pond structures at the mouth of the river near the estuary.

“The recommendations in the report and the implementation thereof will require close co-operation between Technical Services (Water and Sewer) and Integrated Human Settlements particularly with regard to accurate telemetry to improve response times for overflowing sewer lines and planned housing developments at e.g. Heidevallei.”

The approved budget for environmental authorisation for the Bongani rehabilitation installations is R200 000.  Scheepers said that it needs to be implemented as soon as possible. “I advised Council to include the plan in the 2021/22 budget. The estuary as we know is placed first out of South Africa’s 250 estuaries in terms of conservation importance and it not only provides important eco system services, it is also key to Knysna’s economic well-being. We need to address its wellbeing as a matter of urgency.”