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First time Rondevlei dries up in 40 years!

25 Apr 2015 Posted by in Environment, Uncategorized | 3 comments

Rondevlei has pretty much dried up in response to the summer draw down and regional drought that the 2014/15 summer has brought.

The Western Cape wetlands are designed to dry up in summer and flood in winter and are characterised by this extreme fluctuation of water levels. This results in increased diversity of fauna & flora. The drying up of Rondevlei was last experienced in 1974; since then the urbanised nature of its catchment has resulted in the wetland being “topped up” by small amounts of summer rain. Instead of soaking into the ground these small summer showers come down the storm water canals and raise the wetland levels.

The present drought has contributed to low ground water tables across the Cape Flats, which are evident locally in the low water levels in Zeekoevlei and the dying street trees along Victoria Rd. Bird fauna has been quick to respond to the return of a natural drying wetland cycle and Rondevlei this year had over 200 Little Stint, a small wader bird that breeds in the Arctic Circle and feeds on invertebrates on mud flats. This species can thus access its prey, like miggie larvae, since the mud flats are exposed. This is the highest count of this species since the 1970′s. Other wading bird species such as Pied Avocet, greater Flamingo and Black-winged Stilt have all arrived in number. Mammals such have grysbok have moved on to the mud flats to eat the weedy plant species that have sprung up in the past 3 months. Mole rats have extended their tunnels into the now dry vlei bed and have started to eat the roots of the bulrushes (Typha); an indigenous plant that has proliferated due to the polluted nature of the storm water our wetlands receive.

The hippos have also moved to the permanent wetlands adjacent to the False Bay Education Centre, where seepage from the Cape Flats Waste Water Treatment Works keep this wetland permanently full. The delayed start to winter will allow for burning and clearing of some of the denser reed beds before the winter rains (hopefully) arrive.

 

Rondevlei draw down 2015

Rondevlei looking from the South toward Grassy Park with Zeekoevlei to the right.

Rondevlei draw down 2015(1)

Rondevlei as viewed from the second (PW Allen) tower.

  1. naturelover01-08-16

    sad news for all nature lovers.

    Dalton, it seems strange that only Rondevlei has dried up and not the adjecent vleis like Zeekoeivlei and Princess vleis, what could the reason be for this?

    were you able to save some of the endangered todes and and resident fish species?

    regards
    Yolandie

  2. MoonDance01-08-16

    As far as I understand it, this is a good thing, the animals and fish are fine, the vlei is full and the water quality is better than in a long while.

    The weir was opened and left open allowing the vlei to dry (not completely) so it was done deliberately.

    Zeekoevlei didn’t have the same lucky long draw down because the sailers get grumpy when the water is out for too long, I am hoping this year if the drought continues we will be able to have an extended draw down and reap the same benefits that Rondevlei did.

  3. Trevor01-11-16

    Looks beautiful

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