More than R357m to improve water quality at recreational vleis over three years

08 May 2022 in Where We Govern

The City of Cape Town’s draft budget for the next three years aims to invest more than R300 million for remediation of three vleis and R57 million to assist with improving infrastructure-related water quality in our vleis. This investment is part of collective efforts towards reaching the City’s ambitious goal of becoming a water sensitive city.

Together, the draft budgets of the City’s Directorates for Water and Sanitation, and Spatial Planning and Environment, aim to improve water quality in our waterbodies and recreational vleis.

The Water and Sanitation Directorate has budgeted R57 million over three years for the following capital projects:

  • Bayside Canal upgrade

This includes increasing the capacity of the Bayside canal and constructing stormwater treatment ponds, which should help reduce stormwater pollution entering Rietvlei and the Table Bay Nature Reserve.

Increasing the capacity of the canal is needed to accommodate the increased stormwater runoff from the ongoing development of Parklands and Table View. This will help reduce flooding, which can impact sewer lines and pump stations.

The stormwater treatment ponds are designed to improve the quality of the urban storm water runoff in the canal before it enters Rietvlei.

  • Zandvlei Canal upgrade

This will include upgrades to the existing caisson walls protecting the Zandvlei mouth canal from collapse at the crossing with Royal Road. It also aims to protect the upstream embankment and the proposed redesign of the rubble weir, which controls the water level within Zandvlei for recreation, water quality and as a fish-breeding nursery. The Zandvlei mouth management plan, which is integral to the management of Zandvlei and immediate upstream developments (including Marina da Gama), will also be upgraded.

  • Sand/Langvlei Canal Wetland Rehabilitation (R152 000 is being spent on design and planning on this in this financial year)

This involves creating a wetland for the treatment of stormwater emanating predominantly from the Sand and Langevlei canal, which confluences at the area of the proposed wetland rehabilitation. This will include stormwater/flood attenuation, water quality treatment of the runoff through the wetland area, litter grids and additional amenity space for the local community.

The rehabilitation of the proposed extended wetland area will function to improve water quality as the rivers flow through the wetland before entering the upper reaches of Zandvlei. Litter grids will also trap the larger floating litter and heavier objects submerged within the canal before entering the wetland. These structures will then also be cleaned and litter removed, on a regular rolling cleaning programme.

Extensive public participation is also envisaged to make communities more aware of the impacts of dumping all types of waste into the Sand River catchment.

In addition to this, Spatial Planning and Environment Directorate plans to implement the following vlei rehabilitation initiatives over the next three years (R300m):

  • Weed harvesters will be procured for both the Zandvlei and Rietvlei waterbodies: The weed harvesters will assist in the management of aquatic plants. In the case of aquatic vegetation that responds to eutrophication of our urban systems through excessive growth, the weed harvester assists with the removal of these aquatic plants by harvesting them and the nutrients that they absorb. The removal of this vegetative matter therefore allows for the removal of these nutrients from the system in an attempt to restore some of the imbalances created by such pollution. The weed harvesters will also assist in aerating the water it moves through, thereby preventing algal blooms in some instances.
  • Remediation plans: Detailed vlei remediation plans will be implemented at Rietvlei, Zandvlei and Zeekeovlei. The Zeekoevlei remediation plan is in process and the City’s Biodiversity Management Branch is currently finalising the procurement aspects of these projects. This remediation plan process will assess short and long term interventions that would be most effective to restore the ecological health of these systems. The focus on the interventions needed for long term benefits will include dredging and provide information that would form part of an environmental impact assessment for each system going forward.
  • Dredging: The largest intervention planned will be the dredging which will undergo an Environmental Impact Assessment and Water Use Licence process. The dredging is going to be critical but will involve a multi-year programme on all the vleis. Remedial actions such as dredging can cause dramatic changes to the receiving environment in the short term. This is however necessary to reap the longer term benefits of the removal of accumulated pollutants from these systems, which will allow our systems the ability to heal.
  • Zeekoevlei: In addition, Zeekoevlei’s weir will also be lowered to allow greater flushing and a fish ladder will be installed to improve the biodiversity and ecosystem functioning
  • Water Sampling: An additional boat will also be procured for water quality sampling at Zandvlei.

Big water and sanitation investments for the period 2022/23 – 24/25 also include:

  • R755m to quadruple Sewer Pipe Replacement from 25km to 100km per year
  • R300m to double Water Pipe Replacement to 50km per year
  • R529m for Sewer Pump Station upgrades and repairs
  • R3,3bn on Waste Water Treatment Works upgrades, and extensions to Potsdam, Zandvliet, Athlone, Macassar, and the refurbishment of Bellville WWTW
  • R860m for major Sewer Upgrades including the Cape Flats, Milnerton, Philippi, and Gordon’s Bay bulk sewers

‘The vlei remediation programme will result in the long term benefit for the ecological functioning, water quality and the recreational users of Zandvlei, Rietvlei and Zeekoevlei. These vlei rehabilitation interventions together with the canal rehabilitation will allow our systems the ability to heal and function more optimally. I know the City’s Environmental Management Department is very excited to be a part of this visionary programme,’ said the Deputy Mayor and City’s Mayoral Committee member for Spatial Planning and Environment, Alderman Eddie Andrews.

‘The City is serious about tackling pollution and improving the water quality in our waterways and vleis. This investment outlined in the draft budget is testament to this commitment. The City also has its Liveable Urban Waterway Programme, which includes the rehabilitation of the Grootboschkloof, Westlake and Keyser Rivers as well as the channel enhancement of the Zandvlei River. The programme aims to rehabilitate our waterways using nature-based solutions, green infrastructure and water sensitive design approaches.

‘The directorate is constantly looking to invest in our infrastructure and how to improve our operations to meet the demand of changing dynamics due to urbanisation. At the same time, the public can support the City’s efforts and help reduce pollution entering our waterbodies. Pollution is everyone’s business. All of us have a part to play in improving water quality. This includes being mindful of what we flush down our toilets, pour down our sinks and what we do with our waste – do we dump illegally or do we use the solid waste services provided by the City? Let’s work together to improve the water quality in our waterways,’ said Mayoral Committee Member for Water and Sanitation, Councillor Zahid Badroodien.