About
The Upper Riviersonderend catchment is a Freshwater Ecosystem Priority (FEPA) catchment, because of the good condition of the river, and presence of multiple threatened, endemic freshwater species, and the fact that the rivers draining the catchment feed into the City of Cape Town’s largest water supply dam – Theewaterskloof.

Thirsty invasive plants like pines and wattles are replacing the indigenous fynbos vegetation and reducing water flowing through the rivers and into Theewaterskloof – the City of Cape Town’s biggest water supply dam. In an effort to increase water security, and conserve biodiversity, the Nature Conservancy (through the Greater Cape Town Water Fund) is clearing invasive plants at an unprecedented scale.

The project represents South Africa’s biggest freshwater restoration project to date, and if successful could increase the amount of water flowing into the dam by up to 15%. But there may also be benefits for life beneath the surface of these rivers.

Since 2019, the Freshwater Research Centre has been monitoring freshwater biodiversity in the rivers where the clearing has been taking place, with a special focus on the Giant Redfin – a newly-discovered Endangered freshwater fish. Results thus far indicate that the removing the invasive plants will improve freshwater habitats and allow fish like the redfin to thrive.

In addition to the scientific monitoring, the FRC has also led a community conservation and citizen science programme aimed at involving local communities in freshwater conservation, and raising the profile of the areas hidden freshwater life. The project culminated in the building of a 5m-tall Giant Redfin sculpture celebrated a festival called the Rooivlerkiefees! The project is ongoing, in both the community science and ecological monitoring spheres. 

Status
Current

Outputs

• Cape’s endemic fish swimming for survival (Water Wheel 2019)
• Rafferty M, Paxton BR, Bragg CA, Shelton JM, Snaddon K and Frenzel P. 2019. Baseline Assessment for Freshwater Biodiversity Conservation in the Riviersonderend catchment. Report 3: South Africa: Stakeholder Engagement and Analysis. Prepared for The Nature Conservancy by the Freshwater Research Centre. Pp 35.
• Snaddon K, Shelton JM, Frenzel P and Paxton BR. 2019. A Baseline Assessment for Freshwater Biodiversity Conservation in the Riviersonderend Catchment, South Africa. Report 1. River Health. Prepared for The Nature Conservancy by the Freshwater Research Centre. Pp 67.
• Shelton JM, Snaddon K, Paxton BR, Rafferty M and Frenzel P. 2019. A Baseline Assessment for Freshwater Biodiversity Conservation in the Riviersonderend Catchment, South Africa. Report 4: Threats and Interventions. Prepared for The Nature Conservancy by the Freshwater Research Centre. Pp 37.
• Shelton JM, Snaddon K, Paxton BR, Rafferty, M and Frenzel P. 2019. Communities and Freshwater Ecosystems: Upper Sonderend River Catchment, Western Cape Province, South Africa. Final Report. Prepared for The Nature Conservancy by the Freshwater Research Centre. 58pp
• Shelton J, Snaddon K, Paxton B. 2021. Freshwater biodiversity and habitat monitoring at mainstem sites in the Upper Sonderend River Catchment, South Africa. Prepared for The Nature Conservancy by the Freshwater Research Centre. Pp 57.