ZNR #3: Issues & Responses
The 3rd cache, a camo-taped plastic pot, is hidden amongst the extensive tall reeds north-west of the parking location a few metres before a path junction with a side-trail heading back across to the houses.
En route there, I was able to hear and see some of the numerous bird species living on the vlei, including several masked weavers, nesting in the reeds.
To Find the Cache:
Go to the information board near the parking spot @ S 34 5.299 E 18 27.938 and note the following:
- The total number of boxes = AB of which only C are not prohibitive
- The number of boxes showing fish = D
- The last digit of the after-hours emergency contact number given = E
- At the bottom right of the board is a 4-word motto. The number of ‘e’s in this = F.
The cache is hidden <150m north-west at:
S 34 5.B(Dx2)(C-A) E 18 27.(E+1)(F+1)(Cx2)
Conservation Challenges & Management
Despite its many strengths, Zandvlei faces serious challenges - many typical of urban-fringe conservation areas.
Alien Invasive Species
One of the greatest threats to the reserve is invasive alien vegetation. More than 150 alien species have been documented within the vegetation zones. These compete with indigenous species, increase fire risk and reduce habitat quality.
The invasive water hyacinth (Eichhornia crassipes) is a recurring problem, as it clogs large areas of the vlei.
In response, the Zandvlei Trust runs ‘hacks’ (volunteer clearing events) to remove alien plants, often monthly. Also, the natural Cape Flats dune strandveld vegetation is being slowly restored and indigenous plants are collected before bulldozers start working on new developments, and transplanted at Zandvlei.
Water Quality & Pollution
Water quality is a recurrent concern. Raw sewage spills and polluted inflows have sometimes forced closures of parts of the waterbody due to extremely high E. coli counts. For example, in July 2025, these exceeded 4,000 CFU/100 ml, prompting a temporary closure of the estuary to recreational use.
Managing the inflow of nutrients, sewage and sediments remains a significant challenge.
The extensive reed beds are an important part of the river, as they filter out silt and remove nutrients so that the water does not become thick and green with algae.
Recreation vs Conservation
Balancing public access with ecological protection is always tricky. Incidents such as a dog attack on a juvenile Cape grysbok led to a dog ban in sensitive areas (eg. Park Island) to prevent further disturbance to fauna. Similarly, restrictions apply to fishing, bait collection and water-use in certain zones of the reserve.
Urban Encroachment & Habitat Loss
The surrounding suburbs continue to exert pressure via land-use change, noise, light pollution, invasive species spill-over and increased usage. Historically, much of the original dune strandveld and wetland was lost. The remaining patches in Zandvlei constitute rare fragments of once-widespread ecosystems.
Fire Management
The vegetation types, especially the fynbos and dune strandveld, require occasional fire to maintain plant diversity and structure. However, in an urban fringe setting, fire management becomes difficult due to risk to property. This leads to altered fire frequency, which can degrade ecosystem health.
Integrated Management
In response to these challenges, the City of Cape Town has developed an Integrated Reserve Management Plan, which sets out a vision, mission and strategic objectives to safeguard Zandvlei’s biodiversity, while enabling compatible public use.
The involvement of volunteer organisations (eg. Zandvlei Trust) and advisory bodies (eg. Zandvlei Protected Areas Advisory Committee – ZPAAC) is essential in the co-management of the vlei.
