A joint view on what’s happening with the vlei

Following consultations, meetings and discussions with the experts, David Rogers and David Bristow (Zandvlei Trust) and Nick Bode (Marina da Gama Association) highlight concerns, issues and also strong signs of new hope for the future of Zandvlei Estuary Nature Reserve.

Sewerage, weed build-ups and water quality and urban renewal projects were high on the agenda at the latest meeting of the Zandvlei Protected Areas Advisory Committee (ZPAAC), held on 26 January at the Zandvlei Lookout.

The meeting was well attended by key stakeholder groups around Zandvlei, including the Marina Da Gama Association, Zandvlei Trust, Peninsula Canoe Club, Yacht Club, Sea Cadets, Friends of Park Island and the Zandvlei Recreational Anglers’ Association, along with conservation and biological specialists, who have all been meeting monthly since September 2021 to advise the City of Cape Town (CoCT) on matters pertaining to the nature reserve.

Community and transparency was said to be not up to standard generally and this body and its work are now getting up to speed and we hope to keep you informed of these meetings which will be held monthly due to the urgency of the situation.

Photo credit: Wilbur McIlmoyle

A new man in the hot seat

The good news is that the Mayor has escalated waterways, including Zandvlei, as priorities. Also, there was a regular attendee, our ward councillor Amy Kuhl, who often brings a broad perspective on things ‘political’. Unfortunately absent was the new mayoral committee on waterways chairperson, Alex Landsdowne, the man now at the centre of this great big $#!& storm that has many causes upstream, who was scheduled to update us on his work. We hope to be able to engage with him as soon as he is feeling better (get well soon, Alex).

CoCT reported that it is about to appoint various consultants to reinvigorate the 2016 Source to Sea River Corridors and Liveable Urban Wetland initiatives, along with the River Ambassadors and the Adopt a River programmes that lost momentum during the COVID lockdown. Of these projects, the Liveable Urban Waterways Project is extremely relevant and the Westlake, Sand and Keysers Rivers are under the spotlight. The concept is to target pollution culprits particularly in industrial areas, rewild the rivers as far as possible, and also create better spaces for people to enjoy. This will, in turn, enhance the water connections between communities as well as the quality and the flow of water into the Zandvlei Estuary. We are eager to bring people news about these developments and urged the CoCT to keep us informed as far as possible on progress and also gain input from the specialists in the room.

Hats off to Andy

One council employee who deserves special mention here is Andy Taylor, the man responsible for relaying and/or relining the entire sewerage pipe system in the southern peninsula. It’s a hard, tricky and as you can imagine, very dirty job. So, whenever you flush your loo, just give him a thought. The sewage system is old, in some placed dilapidated, and pushed over the edge by human settlement in the catchment over the past few decades. In more recent years it has also been subjected to astonishing abuse and, rumour has it, political sabotage.

E. coli levels down

More good news reported by Kyran Wright of Cape Nature was that E coli levels are much improved in the vlei – but for two major breakdowns during December, one of which remains a mystery. If the trend continues, the vlei could well be opened for recreational use in the next few weeks. 

Weed and algae

The weed infestation which has occurred over the past few months was also a source of concern and brings new challenges. The CoCT has budgeted for weekly drone flights to monitor algal growth and blooms in the waterways for the next two months. This will help to inform the priority areas for clearing by the weed harvester. The CoCT’s teams are also analysing the new strains of algae that have not been seen previously in the vlei. The main causes of the current weed explosion are, as is obvious, sewage spills, but also nutrient flows coming in from the two golf courses upstream at Westlake and Steenberg, suburban gardens (where do you think all the fertilisers and pool backwashing ends up?), and quite possibly the Constantia wine farms.

Our ailing weed harvester

Our very tired and ageing Kingfisher weed harvester has been a source of great concern over many years. Having got a life-saving overhaul and then solving a red-tape issue, it has struggled to operate at full capacity this week due to the recent strong winds. However, it is now operating in the northern canals and has been instructed to focus most of its time in the Uitsig canals this week. Of course, everyone and their dog has an opinion about how it should be doing its job, without ever having tried to operate this noisy, shaking and ancient beast. For two weeks this month, reserve manager Kyran Wright had to take over the controls when the regular operator had to isolate due to a COVID contact. Kyran says his hands and arms have still not recovered, so go ahead and volunteer to give it a try if you are feeling brave and foolish!

The construction of the first of two new weed harvesters is on track to be completed and delivered by June 2022. They are to be run, maintained and operated by third party contractors so, hopefully, there will not be the current maintenance delays with so many layers of government approval required for even the smallest spare part.

Two boat crews with six people each will be hired by the CoCT to mop up alga in areas the weed harvester can’t get to. The contract will hopefully be finalised next month. If there is a pile-up of harvested algae nearby, please bear with us as we try to tackle this never-seen-before infestation.

Estuary mouth management

The mouth is scheduled to be opened at the next spring tide as it’s a great high tide with a height of 1,95m. This will lead to increased salinity that will hopefully slow down some of the worst weed growth. Also, the resultant increased water depth around our houses, by around 20cm, will also allow for greater water circulation, which also helps control the weed-algae infestation*. Recent oxygen and salinity readings are all within an acceptable range and continue to be regularly sampled. Night/early morning oxygen sampling will also be initiated to account for the variable respiration rates of algae.

* For those not aware, the mouth is opened in summer to allow the inflow of sea water, and in winter to allow the outflow of fresh rainwater in an attempt to maintain regular water levels and salinity. The vlei is an artificial lake that was created early in the 20th century – along with Zeekoevlei – to facilitate recreation when rowing was the big thing. Under natural conditions, the vlei (estuary) would have run completely dry in summer. Hence its name Zandvlei. That is also why it needs to intensively managed.

Zandvlei Trust

The Zandvlei Trust, a volunteer group of environmentally concerned residents from all around the vlei, has employed staff to clean up nets, the water’s edge and the Sand River mouth canal. The trust has taken over the tasks that were previously managed by Mike Ryder and also expanded to other areas of the vlei. To be more inclusive, regular monthly litter ‘chicken parades’ are being co-ordinated by the Trust: join them if you can on the first Saturday of every month, meeting at Thesen’s Bridge near Axminster Road on Zandlvei at 9.30am. Bring something to drink, wellies if you have them, and maybe a fork, rake or braai tongs. The Trust will provide bags.

What’s up with the birds?

A water bird census was conducted last week and we look forward to the results. Kyran pointed out that waterfowl are not a particularly good indicator of water quality and numerous species even prefer polluted waterways. For example, some of the best birding in South Africa happens at sewerage works. He believes that our lack of waterfowl is because they are being impacted by the lack of pondweed, which is a primary food source. The big numbers and variety we used to enjoy have moved to other waterbodies and parts of the vlei. Kyran said that they counted more than 300 coots around the Sand River mouth. He believes that this is a wind shielded area and also close to a large pondweed stand. Answering the concerns of some residents, he pointed out that the reason some birds, such as weavers, appear to have abandoned their nests is that it’s the end of their breeding season.

Cleaning up the greater vlei area might at times feel like trying to push water uphill with a rake, but we have to tackle one issue at a time. Many small steps will – with luck, hope and hard work – lead to solutions and a happy, clean water environment.