Understanding freshwater quality in Cape Town

Cape Town is home to a substantial network of rivers and wetlands, as shown in Map 8, that perform a dual function. While acting as a habitat for aquatic fauna and flora, the freshwater system also acts as a natural infrastructure asset for the management, treatment and conveyance of storm water and treated wastewater effluent.

Explore Cape Town’s rivers and wetlands on the CCT website. Many recreational activities can be undertaken in these areas, such as picnicking, taking leisurely walks (some areas allow dog walking), hiking, and bird watching.

The City’s constructed storm water infrastructure (road-side gutters, sidewalk inlets, pipes, canals and detention ponds) merges directly with the freshwater and coastal receiving environments. To manage these connected systems, an integrated management approach is essential for the protection of the environment. The City promotes the concept of water sensitive urban design (WSUD) to move towards a ‘water sensitive city’. This approach includes the focussed management of storm water using established urban watershed and sustainable urban drainage system (SUDS) management tools.

However, on-going organic and inorganic pollution and littering of Cape Town’s storm water and freshwater systems pose a threat to both biodiversity and human health. The City has the responsibility to address the multiple complex factors that impact water and water quality in Cape Town. This requires a multifaceted plan involving multiple departments and partnerships.

In 2012 the City implemented the Inland and Coastal Water Quality Improvement Strategy and Implementation Plan to address water quality issues. With this strategy the City recognises that rivers, wetlands, and vleis have diverse ecological, aesthetic, recreational and infrastructure functions. These functions are essential elements of Cape Town, providing beauty, a sense of place, tourism and recreational and health benefits to residents and visitors. However, many of these watercourses are severely impacted by the surrounding urban and peri-urban areas. With this in mind, the strategy provides a framework to address inland water quality issues to achieve developmental objectives set out by the City. The plan has set priority areas for intervention, including the Disa River (Hout Bay), central Salt River catchments surrounding Athlone, Kuils River catchments below Bellville, Soet River, Mosselbank River (Kraaifontein), and Diep River/Rietvlei Wetland (Milnerton/Table View).

Factors influencing water quality in Cape Town

A variety of factors contribute to water pollution in urban areas, including:

  • Bacterial contamination due to inadequate wastewater collection and treatment.
  • Spillage or disposal of sewage or grey water directly into the storm water system or natural environment within informal areas.
  • Sewage overflows, due to accidental breakage or ageing infrastructure. Illegal disposal of industrial pollutants into the storm water system or natural environment. Run-off from agricultural activities, including fertilizer run-off and animal waste, adjacent to and within the city.
  • Litter and illegal dumping in waterways.
  • Loss of wetlands and other natural systems that provide a filtration function.

It is also recognized that the current drought that Cape Town and the surrounding Western Cape is experiencing has some implications for freshwater quality. However, due to water quality testing being conducted on a monthly basis it is difficult to measure the full extent of the drought on Cape Town’s watercourses.