Zeekoevlei to be dredged in major conservation move

The City of Cape Town has announced a significant environmental project: the dredging of Zeekoevlei, a 258-hectare freshwater lake within the False Bay Nature Reserve. Announced on March 25, by the City of Cape Town, this two-year operation is set to begin in May, aiming to remove toxic sediment and improve the lake’s water quality and ecosystem health.

Zeekoevlei has long faced challenges from sediment buildup and nutrient overload, causing algal blooms, high E. coli levels, and periodic closures, such as in December 2024 due to toxic Microcystin levels. These issues have degraded the lake’s ecological balance and limited its use for recreation like rowing, sailing, and birdwatching. The last dredging occurred in 1983, but it wasn’t enough to halt the decline, making this operation a critical step forward.

The project targets two sections: Storm Bay and Home Bay. Storm Bay will see 207,000 cubic meters of sediment removed over 12 months, followed by 157,000 cubic meters from Home Bay over 14 months, totaling 364,000 cubic meters. Deputy Mayor Eddie Andrews, overseeing Spatial Planning and Environment, emphasized that removing this sediment will reduce pollutants and enhance the lake’s health, aligning with the City’s priority to restore Zeekoevlei, a Ramsar-recognized wetland.

A floating suction dredger—a first for Cape Town—will extract the sediment, pumping it through a 4.3-kilometer slurry pipeline to dewatering ponds. There, the material will dry out, with excess water channeled via a 2.3-kilometer pipeline to the Cape Flats Waste Water Treatment Works. Hydrographic surveys every two weeks will monitor progress, ensuring the operation stays on track. Preparations, including setting up access roads and ponds, were underway by March 2025, with the contractor already on site.

The dredging promises long-term benefits, such as fewer algal blooms, clearer water, and a healthier ecosystem, supporting biodiversity and recreational use. However, residents and visitors should expect temporary disruptions. From Monday to Saturday, with possible Sunday and holiday work, noise and an odor from disturbed sediment are likely. While rowing and sailing can continue in open areas, safety closures will restrict access to parts of Zeekoevlei and the reserve, though birdwatching spots will largely remain available.

Historically, Zeekoevlei—once noted by Jan Van Riebeek in 1656 as a vast lake teeming with life—has shifted from a hippo habitat to an urban waterbody plagued by pollution from nearby farming, sewage, and seepage. Past interventions, like annual drawdowns, couldn’t keep pace with the degradation. This operation, the most ambitious since 1983, reflects a modern approach with advanced technology and a focus on sustainability.

While no major controversy surrounds this specific project, water quality issues have long frustrated locals, with sewage spills and algae prompting community concerns. The City hasn’t detailed the final use of the dried sediment—possibly for land reclamation—but promises updates as the project progresses. Set to conclude around mid-2027, the Zeekoevlei dredging could restore this vital waterbody, blending environmental care with community needs in Cape Town’s ongoing ecological efforts.

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