ATT: Save the Zandvlei petition promotors/concerned residents
CITY RESPONSE TO CONCERNS ABOUT INLAND WATER QUALITY AND POINTS RAISED IN “SAVE ZANDVLEI” PETITION
The City notes the concerns raised in the “Save Zandvlei” petition, as well as the broader water quality challenges across the metro, and would like to engage residents in the most meaningful and transparent manner possible.
A local stakeholders meeting took place on 23 April 2021, at which key information regarding pollution abatement efforts were communicated to attendees. The City’s Catchment, Stormwater and River Management Branch, in collaboration with Cllr Aimee Kuhl, are planning a Sand River Catchment public open day, where various line departments responsible for pollution mitigation will have various exhibits. Respective line department officials will be available at these exhibits to answer questions relating to their core expertise. As the Sand River catchment is a much bigger catchment, spanning many wards, the other relevant local ward councillors will also be available at this public open day.
The Zandvlei waterbody was closed to members of the public today (25/05/2021) due to compromised water quality as a result of damaged pumps at the Clifton Road pump station, which led to sewage entering the vlei. Microbiological test results indicate that E.coli levels exceed the thresholds for safe intermediate recreational contact with water.
Observations on site indicate that foreign objects in the sewer line were likely the main cause of the fault. A replacement pump was installed by Monday morning, which has reportedly stopped the overflow.
This closure shall be in effect until water quality returns to satisfactory levels.. Comprehensive follow up sampling is scheduled for this week and will continue until it is determined that the water is safe for intermediate recreational usage.
This is the fourth occasion in two years that Zandvlei has been fully closed due to contamination associated with sewer spills.
The Clifton Road Pump station linked to the Royal Road Bridge spill has been operational since 11h30 Monday 24/05/2021.
ZANDVLEI ESTUARY – WATER QUALITY CONCERNS
The City of Cape Town manages the three large recreational vleis (Zandvlei, Zeekoevlei and Rietvlei) which are used for a variety of water sports, namely sailing, power boating, canoeing, rowing, windsurfing, and fishing. All three vleis are located in proclaimed nature reserves.
Zandvei is the only functioning estuary on the False Bay Coastline. Estuaries are generally highly productive ecosystems, and provide a range of goods and services ranging from nursery areas for juvenile fish, to stopovers for migrant birds, and recreational opportunities for local inhabitants. The diversity and amount of fish and other life in Zandvlei is staggering (30 fish species) and include sandprawn, white steenbras, leervis and harder. For example, in the 2012 fish die off in Zandvlei as a result of a golden algae bloom, it was estimated that only 10% of the fish actually died. You might remember the large volumes of fish that surged out of the vlei over a period of about a month.
Detailed Water Quality results
Over the last 2 years, Zandvlei was fully closed to recreational activities due to sewage spills on four occasions:
15/05/2019- 31/05/2019 (full)
26/06/2019 – 04/07/2019 (full)
Two of these closures began as partial closures and were upgraded to full closures after further testing was done. Whilst the Zandvlei waterbody was closed at times during 2020, these closures were solely due to lockdown regulations and not linked to water quality issues.
The continued and numerous sewage spill incidents into the Zandvlei waterbody have been a long standing concern, with particular apprehension around the cumulative impacts on the water quality and ecological health of the system.
Discussions initiated by Biodiversity Management in 2018 with all relevant line functions around short and long term interventions to prevent this contamination resulted in a very positive collaborative effort. The area subject to most of the recorded incidents was identified as the Sand River Canal, in particular the storm water outlet below the Coniston Park litter trap. The Water and Sanitation department was already in the process of implementing a significant intervention to address challenges confronting the reticulation system, which entailed the upgrade of Lowlift Pump station in Retreat and the replacement of specific pipelines (further detail on this project may be found below, under the section outlining specific sewer infrastructure projects, both operating and capital, that have either been completed or are underway).
As this was an effective long term solution, focus was shifted to a short term intervention that could be implemented during the above-mentioned construction phase. Stormwater Management and Sanitation staff assisted in providing a final design and the subsequent implementation of a portable wooden weir structure that would be fitted to the side channel of the Sand River canal (containing the stormwater outlet through which sewage overflows are channelled into the canal). This structure would effectively dam up and contain spill events that would then be removed from the canal via a Honeysucker vehicle to prevent the pollutants entering the Zandvlei waterbody. This system was made operational and used successfully to contain a sewage spill on 24 January 2020 for the first time. This structure has significantly reduced pollution of the vlei. This partnership collaboration delivered an inventive solution with significantly positive results for this system. The commitment and dedication of the teams involved in taking on challenging situations and improving service delivery are commendable.
The City has a dedicated water quality monitoring programme which measures chemistry, bacteriology, and algae at these vleis. The best indication of water quality and ensuring that the water is safe for recreation is to monitor the bacteriology as well as the algal species and their abundance. Blooms of algal species, such as the golden algae and blue green algae can cause health issues for humans and wildlife. Thresholds for Microcystis (toxin produced by Blue-green algae) and Chlorophyll speak to algal blooms, and may be viewed in the link below (as published in the 2021 Inland Water Quality Report available on the CCT website).
and-wetlands/cape-towns-rivers-and-wetlands#Heading2). The intermediate contact is most relevant for Zandvlei as the water sports (such as sailing, canoeing, and windsurfing) conducted in the vlei are all intermediate contact.
Test results from the recent spill currently affecting the vlei are being processed and will be communicated once finalized.
The below information from the database also shows the results for Jan and Feb 2021. This indicates 4 consecutive months (with the March and April results) of E.coli counts well within the threshold for intermediate contact recreational use. There have been no sewage spills recorded during March that I am aware of, apart from a sewage spill on the 13 April 2021 which was contained to the Sand River canal by using sand bags. This helps demonstrate that there are only limited windows in which intermediate contact with the water carries increased health risks. Where there is a water quality incident a co-ordinated response between the Environmental Management Department and Water and Waste, as well as a number of other line functions, is undertaken to both limit pollution and mitigate risks to water users.
Most issues highlighted emanate from outside the nature reserve and include sewage overflows and spillage, solid waste washing in from canals, and polluted stormwater. Civil unrest in the Capricorn/Vrygrond area in the past few years has exacerbated the issue with the blocking of waste water reticulation pipes and the destruction of sewage pump stations. The resultant sewage overflows reach Zandvlei through the storm water system. There is an action matrix after each major incident which is drawn up by the relevant official from the Catchment, Stormwater and River Management Branch in collaboration with other line departments (EMD, Health, Water & Sanitation and Solid Waste Management), and where necessary the vlei is closed until water quality improves to acceptable levels again.
In summary, Zandvlei’s water quality challenges are generally in line with what is expected for an urban system and are normally well within acceptable water quality standards. The City continues to strive towards improving the water quality of Zandvlei and our other watercourses despite the many challenges these systems face within the urban context. A more comprehensive explanation of the current status and long term trends of the water quality in Zandvlei and other waterbodies across the City is provided in the reports available on the City website, as indicated above, and provides a very succinct summary of the conditions of these urban settings to the public.
SEWAGE LEAKS AND POLLUTION
We therefore ask for:
• A written undertaking outlining the short term achievable actions (12 months max) of the CoCT to protect Zandvlei from future sewage and industrial spills.
Sewer infrastructure projects, both operating and capital, that have either been
completed or are under way
The City allocated approximately R350 million between July 2019 and June 2021 on upgrades and rehabilitation of the sewage network.
Items specific to Zandvlei:
New Pump Station in Military Road; Refurbishment of Retreat Main Pump Station; Lining and re-laying of the main sewer through Seawinds / Vrygrond
The new pump station (Low Lift) is almost completed and should be commissioned by the end of May 2021. We have already seen a dramatic reduction of sewage flow into the Sand River, the regular spills will certainly cease. The new station has vastly enhanced backup systems in place to deal with challenges like loadshedding.
The sewer pipeline between Low Lift and Retreat Main required refurbishment. This 1200mm sewer was rehabilitated (CIPP) and a section re-laid as part of the pump station contract – we are now blockage / sewer spill free from that source, so a huge success there (completed).
Further to this Retreat Main pump station was also refurbished and brought up to modern standards (completed).
All of the above works were executed as part of the Low Lift contract. This project has recently been completed and will be commissioned shortly despite the attacks and damage to plant and equipment on site during the construction.
Re-lining of the sewers on the Muizenberg beachfront to prevent sand ingress into Axminster Road
Scope: CIPP Lining of the sewers in Beach Road, Atlantic Road and the Roads on the mountain side of Main Road
Status: completed Budget: R4.5 million
Benefit: reduction of blockages, improving the water quality of the Muizenberg beachfront as well as the Zandvlei Estuary
Cleaning of sewers in Axminster and Clifton Roads
Scope: Removal of sand from the 800mm diameter sewer in Axminster and Clifton Roads
Status: completed Budget: R 1 200 000
Benefit: reduction of blockages, improving the water quality of the Zandvlei Estuary
Cleaning of sewers on Albertyn Road
Scope: Removal of sand from the 300mm diameter sewer in Albertyn Road Status: completed
Budget: R 50 000
Benefit: reduction of blockages, improving the water quality of the Zandvlei Estuary
This is over and above the regular day to day blockage clearing and other maintenance work.
A Pollution Abatement Strategy and Action Plan (PASAP) specifically for the sand River catchment is in development and is expected to be finalized by the end of August 2021. This forms part of the City’s Water Quality Improvement Programme and will include sewer spill pollution.
The City will continue to respond to sewer incidents as timeously and effectively as possibly, as per the Sewer Incident Management Protocol. The emergency protocol for Zandvlei involves direct communication with stakeholders and resident groups.
SEDIMENTATION AND SILTATION
We therefore ask for:
• the current plans of the CoCT that will be implemented to effectively resolve the silting and sedimentation problem.
· Opportunities for silt and litter traps within the broader catchment will be identified through the PASAP (refer above)
· The City has also initiated the Liveable Urban Waterways (LUW) Project. The project intends to naturally canalise sections of river and construct nature based solution/wetlands to assist with water quality and biodiversity improvements. It is intended to address multiple issues regarding water entering Zandvlei. The overall goal is to intercept and clean water coming down the Sand River and Langevlei rivers, focusing particularly on nutrient loads, litter, sediments and sewage. Extensive public participation will be involved and the project has already been introduced at the recent ZPAAC meeting held on 30 March 2021. What’s exciting about this project is that we can address water quality before it enters the vlei and improve the ecological habitat of the area.
· Stage 1 dredging within Zandvlei (from the river mount into the vlei) was undertaken using long-boom and amphibious excavators in the 2019/2020 financial year
· Stage 2 dredging was undertaken this financial year (Aug/Sep 2020)
· Stage 3 dredging is planned for this financial year (May/June 2021)
· Mouth management: The opening/closure of the mouth is done using dozers, which is an effective way of moving significant volumes of sand. The mouth is opened in winter to prevent flooding properties adjacent to the vlei. Regarding the rubber weir and mouth closure, it should be noted that without this Zandvlei would completely dry up in summer months as there is simply not enough water coming down to maintain water levels naturally. Zandvlei estuary and catchment was progressively and extensively modified since 1930 which has left a long legacy of artificial manipulation of the system. The City aims to manage the system in accordance with the legislative requirements and in line with the ecological best practice stipulated in the comprehensive assessments and action plans detailed in the Zandvlei Estuarine Management Plans (dated 2010 and 2018 (draft)).
CANAL CLEARING AND LITTER TRAPS
We therefore ask for:
· Confirmation from the CoCT that a contract for the clearing of the canals will be finalised before 30-04-2021 and be renewed on an annual basis.
· Assurance that the canals will be cleared manually or mechanically monthly, as well as before every rain event, should the state of the canals require it.
· An undertaking from COCT that all available measures will be taken to ensure access to the canals at known dumping hotspots is prevented.
· Tender 121S/2019/20 (ref 1st bullet point above) has been active since 01 April 2021 (Inaugural meeting held with Contractors on 01 April 2021) and cleaning activities will start to ramp-up as Contractors mobilize and deploy their teams.
· Canals / litter grids are currently cleaned every two months. Monthly cleaning is currently not viable due to budget constraints, but will be reviewed in future budgetary processes. Litter grids will be cleaned a day before rains, and every day throughout the duration of the rain event.
· Illegal dumping is primarily a Law Enforcement and Solid Waste mandate, but does require the cooperation of multiple stakeholders. Dumping hotspots will be considered in the proposed PASAP (refer above).
Algae in the Marina
The vlei and Marina have been prone to higher than usual filamentous algae growth, this is not unexpected in eutrophicated urban systems. The current situation is thought to be due to a few compounding factors which could include the following: pondweed stands are recovering from an absence in the previous season, which has provided a niche for additional filamentous algae growth in eutrophicated conditions, as well as unseasonably late winds which has led to increased evaporation, lower water levels and higher water temperature. These circumstances compounded by the lack of biomass removal by the weedharvester machine, which also assists with water mixing and aeration, creates favourable conditions for algal blooms. Such algal blooms can reduce dissolved oxygen levels within waterbodies. Low oxygen levels can in turn affect aquatic organisms negatively. The City continues to monitor dissolved oxygen levels in the Marina and main waterbody, as well as the occurrences of algal blooms.
We therefore ask for:
• A copy of the tender issued for the new harvester, written confirmation of the procurement status with a date of delivery, and if complete, the name of the successful bidder.
• If a procurement process has not started, then a copy of the last minutes at which the new harvester was discussed,
• A clear explanation as to why the existing harvester has been inoperative for several months for what is believed to be a minor repair.
• A copy of the minutes of the last meeting where the repair of said harvester was discussed.
• A summary of the monthly operating hours for the past 24 months.
The Zandvlei Weedharvester was inoperable for some time due to a few mechanical faults (such as the bearings on the rear conveyor belt). Notifications for the repair were timeously submitted, however, due to delays associated with a new supply chain management process recommended by the Auditor General, the repairs took months to complete. Repairs have now been completed, and is currently operating.
Furthermore, the tender for the new weed harvester tender has been awarded. The MOA was signed and the vendor has indicated that the anticipated delivery date is December 2021 / January 2022.
The City of Cape Town recently released its Inland Water Quality Report. The report covers historic water quality trends in the major rivers and open waterbodies in the city, and also focuses on the five-year period from April 2015 to March 2020. It details key challenges towards improving the health of urban waterways. Going forward annual data will be used to assess the efficacy of programmes and activities aimed at reducing water pollution. The summary booklet and technical report are now available to the public here, Link to the Inland Water Quality Report Summary: http://bit.ly/CCT-
InlandWaterQuality2019; To view the full report,
visit w ww.capetown.gov.za/ThinkWater
The City would also like to invite the petition authors, along with a limited number signatories (due to necessary precautions related to mitigation of the spread of Covid-
19) to join us in officially opening the newly upgraded Retreat Pump Station, whose new design will significantly reduce the number of pump station failures due to blockages, and ensure a vastly improved reticulation of the sewer system in the area. The project is at an advanced and final completion is scheduled for the latter half of June 2021. A formal invitation will be forthcoming once details are confirmed.
Director: Bulk services