As the first newsletter for this
year, the Committee would like
to wish all members and friends
all the very best for 2008. We
hope that this will be an
environmentally aware year for
you and that you will make an
effort to support the
conservation efforts at Rietvlei
in every way.
Our first Activity for 2008 was a walk to the bird
hide on Sunday 3 February to coincide with World
Wetlands Day. Niel van Wyk reports as follows:
Saturday 2nd February was World Wetlands Day, to
commemorate this day we had a walk to the Bird Hide
on Sunday 3rd February. February is Wetlands Month.
The Ramsar theme for Wetlands this year is "Healthy
Wetlands, Healthy People" - this basically means
that having healthy well-functioning wetlands can
only enhance the health of people the world over.
Wetlands cleanse water and improve its quality, they
prevent flooding, and they can counter the effects
of droughts. Wetlands also support a large variety
of living organisms and are important in many
aquatic and terrestrial food chains. As such
wetlands are important sources of food for local
communities in many parts of the world, either
directly in the form of fish, or indirectly where
crops are planted and grown on the floodplains
during dry seasons - these floodplains are allowed
to flood during the wet seasons during which time
the soil is enriched by nutrients.
There were about 10 people on the walk to the Bird
Hide at Rietvlei. The strong south-easters of the
previous days (or weeks!) had died down and the
weather was really pleasant for walking. When we
started off it looked as if it could rain, but this
soon cleared up. Of special mention is the sighting
of two fish-eagles that kept us company for most of
As usual, Niel has posted the photographs taken on
the walk on the website. They are stunning
photographs and you are encouraged to take a look,
whether you were there on the walk or not.
Our first Evening Talk will be held on Thursday 6
March. Our speaker will be Pat Holmes and she will
be speaking on “Riparian Restoration” of fynbos.
This interesting talk and power-point presentation
on restoring the natural vegetation along river
courses is of interest to us as we have our fair
share of alien vegetation along our river and vlei.
Please join us at the Rietvlei Education Centre,
Table View, at 7:30 for 8:00pm
Queries? Phone Pauline on 083 255 2537
Annual General Meeting: An early notification of our
AGM - it is going to be held on THURSDAY 8 MAY 2008,
in our Education Centre. More details nearer the
The school year has begun and we are hoping to be
playing host to a greater number of schools on
environmental outings. Elana Kellerman was a
conservation student at Rietvlei in 2007 and she has
been appointed by the City of Cape Town as an intern
for a year to do environmental education. We are
hoping that she will spend a substantial amount of
time at Rietvlei. She will possibly be occupying the
office in the Education Centre if a telephone line
can be installed there. In the meantime she can be
contacted via the gate number, 021 557 5509, if you
know of any group wanting to visit Rietvlei.
Potamogeton in Rietvlei
A problem to the recreational users of Rietvlei is
the excessive growth of Potamogeton pectinatus, the
water grass also known as sago pondweed, or
fennel-leaved pondweed. It has always been present
in Rietvlei, but the last few years have seen a
bloom in growth.
There are about 20 Potamogeton species, most of
which occur only in the northern hemisphere;
Potamogeton pectinatus is the only one found
throughout the world. It grows in wetlands, lakes,
rivers, canals, ditches and ponds from sea level up
to nearly 5 000m above sea level; it is also the
only Potamogeton species found in brackish water. It
has been recorded growing in waters 6-7m deep, but
it is dependent on light penetration and in turbid
waters will rarely grow in waters deeper than 3m.
Potamogeton stands are important feeding and rearing
habitats for waterfowl, fish and many other
organisms. It is not only a source of food, but also
provides a protected habitat for many aquatic
animals. In many parts of the world migratory
waterfowl have established their migration pathways
via water bodies dominated by Potamogeton spp.
Potamogeton also protects shorelines from erosion as
they serve as a very effective buffer against wave
action. Potamogeton plays an important role in
keeping water clear.
However, there is also a downside to Potamogeton.
Because it grows so prolifically, it can clog
irrigation canals and is a nuisance to recreational
users – it interferes with fishing lines and winds
around powerboat propellers.
A lot of research into control methods has been
carried out throughout the world, including the use
of herbicides and other chemicals, mechanical
methods and biological control. A burrowing
chrysomelid beetle causes great damage to
Potamogeton, but has not permanently eradicated the
plant in study areas. Grass carp was introduced into
the United States to control aquatic plants, but it
has exterminated virtually all aquatic plants in
water bodies to which it had been introduced and
caused a complete collapse of the ecosystem –
leading to the disappearance of other fish and bird
life in such systems.
The problem recreational users, such as the boaters
and fishermen, have with Potamogeton in Rietvlei
will not be easily solved. In fact people using
Rietvlei will have to accept that the plant is here
to stay and learn to live with it. The only remedy
is to clear channels in the Potamogeton stands to
allow boats access to the shore, it can also be
cleared in areas where anglers require access to the
water. However such clearing will have to be
repeated at regular intervals to ensure that
channels stay open.
RAIN in February (not to mention the WIND)
The wind seems to have been unrelenting so far this
year. It is known as The Cape Doctor, but judging by
the number of people who complain of allergies,
hay-fever and sinus problems when the wind is
blowing, this could be a misnomer! But … there have
been some days of rain. At this time of the year
many people are worried about the Central Pan drying
out and that heavy winds will lift the fine silt and
blow it over Flamingo Vlei. The City of Cape Town
has instituted measures that were agreed to at the
start of the financial year in July 2007. In January
two diesel pumps were installed in a temporary shed
on the southern edge of North Vlei. The pumps are
pumping water on a daily basis onto the central pan.
The good rains of early summer also helped to keep
the pan wet. Unfortunately the heavy southeasters
and high temperatures have done there bit to
accelerate evaporation. At present the pan seems to
be wet enough.
The City’s Roads and Stormwater
Dept has appointed consultants
to plan the upgrading of the
stormwater channel that runs
past Bayside Shopping Centre and
Pick’nPay and enters Rietvlei
just south of the soccer fields.
Capacity for stormwater and
water quality, are issues that
will be investigated. There will
be a public participation phase
to the project.
The new Integrated Zoning Scheme
(IZS) for the entire City is out
for public comment. Niel Van Wyk
investigated the maps and zoning
for Rietvlei and picked up some
discrepancies and concerns.
These will be submitted to the
Spatial Development Frameworks
(SDF) for the 8 Planning
Districts of the City are being
prepared. The SDF for Blaauwberg
will be available for comment
soon. The questions being asked
How do you see the future of the
Do you think Cape Town should
spread out as far as possible?
Or that new buildings should be
at least three stories high, to
help prevent urban sprawl?
Do you think it's worth
preserving endangered fynbos
rather than building houses on
it? And if so, where should new
houses be built instead?
And how are we going to connect
Capetonians with each other, and
with economic opportunities?
Through better public, or
The Committee will be actively
involved in the above matters
and will submit comment where
necessary…. So can you!!
|Thanks go to Chevron Refinery for
sponsoring envelopes for the posted newsletter.