Phase two of Lower Silvermine dredging in full swing
The City of Cape Town has allocated approximately R3 million for phase two of the Lower Silvermine Wetland which will include dredging to remove silt, alien vegetation, and reeds.
As part of the City’s ongoing river maintenance plan, upkeep of the Lower Silvermine Wetland began in February as the breeding season of the endangered Western leopard toad ended in January.
The City’s mayoral committee member for water and sanitation, Zahid Badroodien said as part of the current phase, approximately 79 000m2 of wetland will undergo dredging.
The dredging will start from the Western leopard toad pond down to the bottom, near Main Road.
The maintenance, he said, is designed to enhance inland water quality, a primary objective within the City's water goals.
R6 million was allocated for phase one and work on phase two is expected to be completed by the end of June.
Mr Badroodien said the maintenance will improve breeding conditions for the Western leopard toad and promote the growth of indigenous plants, among other benefits.
He said the wetlands are an essential breeding ground for the Western leopard toad and toads can travel up to 2.5km to the breeding ponds to lay their eggs. Once they leave the ponds, the eggs hatch, and the tadpoles feed on algae situated at the bottom of the ponds.
“It is essential that the ponds are kept fairly open so that light can reach the bottom, enabling algae to grow, he said.
At present, he said, the reed beds have expanded and increased due to siltation. Siltation of the ponds changes the depth of the water making it shallower, which is to the advantage of the reeds.
Under natural flow, the reeds would drown in deeper water profiles and result in sections of open water, bringing about a diversity of aquatic and semi-aquatic plants instead.
“The reeds have been creeping up the river embankments and displacing plant species from the Strandveld vegetation type which is an endangered veld type,” he said.
The current levels of siltation in the ponds have resulted in the decreased hydrological capacity necessary for flood prevention and if left unattended, the ponds will be unable to prevent flood waters from damaging adjacent residential properties.
“The importance of well-maintained inland waterways cannot be emphasised more. They are places where recreational activities can be enjoyed, while also being safe for wildlife to thrive, keeping our diverse ecosystems alive,” he said.
Friends of the Silvermine Nature Reserve (Fosna) chairman Dave Balfour said Fosna has been working with the City to implement effective conservation management in the Lower Silvermine Wetlands and are delighted to see it come to fruition.
“The conversion of a homogenous stand of reeds into a more diverse ecological setting has resulted in increased bird diversity and a number of sightings of Cape clawless otter, while at the same time keeping the area open and safe for local residents to enjoy. We congratulate the City for this effective urban conservation management,” said Mr Balfour.
