Intaka Island Wetlands – how does it all work?
We have recently received a few comments and questions about Intaka Island and why the Wetlands look the way it does? In the following months, we will be doing some informative posts, to tell you more about how the wetland was originally designed and what maintenance is done by our teams to ensure the island is maintained to its intended state, as well as some interesting facts and finds made by our teams on the Island.
The wetland is mainly divided into two sections. The management approach to these two areas is vastly different in order to meet their specific objectives.
The Eastern half consists of seasonal saltpans and indigenous sandplain fynbos, which are both rare habitat types in great need of conservation. The saltpans dry up naturally during the summer months but fill up with good winter rains. All seasons support a unique array of faunal species.
The Western half of Intaka Island is made up of constructed wetlands which mainly serve the needs for water purification, habitat for breeding water birds, and the recreation of visitors and education of school groups. This section is made up of 4 very distinctive cells.
To the layman eye, some of these might seem “overgrown with reeds”, “swamp-like”, “too shallow”, or “full of weeds or muck”, but they were in fact designed to look that way, as it mimics the various stages of a natural wetland system.
Cell 1 & 2
The first two cells are dominated by dense Cape reed beds (Phragmites). These fast-growing plants were introduced into the cells, as they can absorb large amounts of phosphate and other nutrients, thus starting the cleaning process.
The surface areas of these cells were designed as large and shallow areas, and so allow for the growth of reeds and for oxygen to re-enter the water. The reed beds also create a habitat for a large number of birds.
From time-to-time dense reedbeds are cut back by our teams – you might have seen some of these swatches on the island. This is mainly done to encourage fresh reed growth and creates more open water bodies for wader bird- and other species.
Cell 3
This cell is very different from the first two in that it is relatively large and deep, comprising mainly of open water. This is done to expose the water to wind, which aids the oxygenation process of bacteria that break down the nitrogenous compounds that flourish in this open water.
Cell 3 is also home to the award-winning heronries (wooded islands), which are designed to encourage birds to roost and breed.
Aquatic vegetation you might have seen sometimes covering the waterbody, was intentionally introduced into the system to aid in the uptake of nutrients. The most common aquatic plants found at Intaka wetland include duckweed & pond lilies (floating), hornwort & pondweed (submerged); and common cattail & bulrushes (emergent).
Through selective, manual removal of these plants, by our dedicated canal maintenance and conservation teams, nutrients especially phosphorous is removed from the system and in turn aids in the overall water quality of the wetland. Aquatics are therefore crucial in the overall ecological functioning of the wetland and Century City waterways. Read more on the role of aquatic plants in the broader Century City https://centurycity.co.za/where-have-all-the-aquatic-plants-gone/
Cell 4
The last cell is once again different from the other cells in that was designed to be a very shallow marshland, with high diversity of vegetation that adds the final step to the water “scrubbing” process before the water re-enters the canal system.
Intaka Wetland & Century City canals.
Recycled canal water flows by gravity though the wetlands, completing a round trip in approximately 65 days. After completing this cleaning cycle in the wetland, the water is then pumped back into the Century City canals. The Century City canals are approximately 8.5km long, with an average depth of 1.6m. The canals are naturally replenished by the underground water table and rainwater. That is why you might see a drop in water levels during the peak of summer, as you would in the remainder of water bodies in the broader Cape Town region such as Rietvlei, Zandvlei, etc. The canals quickly fill up during winter months, which also aids in flushing the system. Read more on how we manage the canals as part of a sustainable urban drainage system https://centurycity.co.za/rain-in-abundance/
Get in contact with us!
Please note that it is not always possible for us to respond to messages and posts on 3rd party platforms.
We would therefore like to encourage you to follow our official pages: https://www.facebook.com/IntakaIsland, https://www.instagram.com/intakaisland/
Keep an eye on these platforms for future posts on species supported by the wetland, our Intaka team, management programs, annual fish survey, bird counts and many many more.
If you’re in the area, feel free to pop in at Intaka’s reception desk and we will gladly assist with any request or questions you may have. We look forward to your visit!
Tel: 021 552 6889 | Email: info@intaka.co.za | Website: https://intaka.co.za/
