Contents
of April 2003
EDITORIAL
Blue arrows and Syringa furniture
UPFRONT
News
IDENTIFYING INVADERS
Pickerel Weed and Honey Locust
BOOK
REVIEWS
TREE OF THE ISSUE
Graeme Leitch chooses
Berchemia discolour
FEATURES
Gas from waste – an energy source
Phytoremediation of nickel
contaminated soil
Rehabilitation of strip mines
‘Self-regulatory’
environmental work
Habitat creation to encourage wildlife
Solar heat and energy demonstration
centre
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EDITORIAL
Blue arrows and Syringa furniture
Urban Green
File has been peripherally involved in what can only be described as an ongoing saga
– a saga which is hope¬fully closer to a satisfactory ending, but is not quite there
yet. The saga concerns Working for Water (WfW) and the ‘painting of blue arrows’
in the Wolkberg and other parts of the Limpopo Province. On 23 October we had a letter
from Haenertsburg based, consulting ecologist Cathy Dzerefos. She described WfW’s,
what she called, “crazy policy” of painting blue arrows on boulders and
indigenous trees to indicate to their teams the areas in which invasive plants were to be
removed. (The blue marks were also on mature aliens but this was hardly a cause for
concern as they were about to be removed.) She pointed out that the Wolkberg Wilderness
Area had been highlighted as a centre of plant endemism as well as an important water
catchment and, as she said, “…it is very wild and precious”.
She
explained that she had spoken to various WfW managers over the months and although they
ap¬peared to be concerned, nothing was being done to stop the painting or remove the
unsightly arrows. She qualified her complaint by saying: “The situation is very
frustrating as the Working for Water Programme is providing a very important service in
the catchments. However, they need to know that professionalism and environmental
protection cannot be sacrificed so that they can carry out their job.”
UGF
suggested that an attempt be made to expedite the removal of the disfiguring arrows
through contacting Guy Preston, national leader of the Working for Water (WfW) Programme.
Months and many, many emails later (with apologies from Guy for the time taken), Cathy
emailed a more hopeful message saying that she had (on 27 February) finally had a meeting
with Etienne De Lange of WfW’s Tzaneen office: “The blue arrows idea has
definitely been scrapped. Non-oil based thinners and steel brushes are being used to
remove the marks,” reported Cathy.
She added
that instead, but only temporarily, brown marks were being used. These were not at eye
level or on permanent features. The long term plan was to use aerial mapping to identify
stands of invasives for clearing. Etienne explained that the identification of invasive
trees was a difficult ongoing educational process – and that occasionally indigenous
species were removed, accidentally. He said it was not easy to keep on training new
contractors in such a specialised field and that marking systems had, as a result, been
introduced.
Cathy asked
that landowners contact Etienne directly if they knew of blue arrows that had not yet been
removed, saying that it was apparently a logistical nightmare to ensure that all the
arrows were removed, as nobody was certain exactly where they all were. She added:
“I do
sympathise with Etienne but to win the battle against alien plants, WfW need the public on
their side and this has not been well handled.” Etienne De Lange’s number is:
082 803 5900. UGF would like to commend Cathy for her persistence in this matter.
The
photographs show a road crossing in the upper catchment of the Letaba River which is
defaced by blue arrows on a rock face and an arrow on a Celtis africana trunk in the
Georges valley which was repainted by WfW two days after the owners of a tent camp for
tourists had removed the mark, which they found aesthetically displeasing. The bark was
damaged in the process. Farmer and owner of the tent camp Jan Fouche reported, in early
March, that although WfW were operational in the immediate vicinity these marks had not
yet been removed. He said that the Letaba River valley was full of blue arrows, hundreds
of them.
But there is
still so much good news where WfW is concerned. WfW’s secondary industry programme
which links manufacturing teams to clearing teams has seven pilot projects running,
countrywide. And one of these, the Po Land project, is making furniture out of Syringa
wood. The colours of the wood, as can be seen from this patio chair, are indeed beautiful
and the texture and quality of the wood is ideal for furniture making. Dr Stefan Neser of
the Plant Protection Research Institute, who calls this notorious invader a wasteful user
of water, has spoken about its value to the furniture industry in South America. (See
article on controlling Syringa in UGF Nov/Dec 2000.)
WfW rates
the exotic Syringa (Melia azedarach) as one of the two most wide¬spread alien invasive
plants in the sub-tropical areas of South Africa. It has invaded an estimated area of 3
million hectares. Now a group from the so called Po people, who live on a piece of land in
the Cradle of Humankind that has been returned to them by a local farmer, and work at WfW’s
Furntrain near Hartbeespoort Dam, have produced a sample range of carefully crafted
Syringa furniture.
This year
Sue Heathcock, consultant to WfW’s secondary industry programme, will be marketing a
large range of furniture being made from the exotic wood cleared by WfW’s teams,
countrywide. A catalogue will soon be forthcoming and UGF will keep readers informed.
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UPFRONT
Demolition rubble
recycled at Airport City
The
multi-million rand Airport City site was once an area of natural strandveld on the Cape
Flats. The land was acquired by the Durr family for their farm Duinefontein in the late
1800s and used as grazing land to support a small dairy herd. With the growth of Cape Town
came development – main roads, outlying suburbs, the city’s international
airport and the N2 motorway. These construction projects required cement and underlying
much of the Cape Flats was calcrete limestone. This was quarried and fed to the Philippi
cement manufacturing plant. Another requirement was sand and so the dunes started to
disappear leaving a deep hole. The site then lay un¬used for years until the pace of
growth of the city outstripped the supply of convenient dumping sites for construction and
demolition waste.
For a small
fee, builders and demolition companies were invited to fill the huge hole and this
resulted, over time, in a 20ha dumping site. A number of developments in the city, such as
Thibault Square and the BP Centre generated huge volumes of rubble from demolition and the
blasting of bedrock bluestone for the excavation of deep foundations. Much of this waste
made its way to the Durr dumpsite.
The demand
for industrial land then started to stretch out towards the airport and the present
generation of Durrs decided to use the space for a new concept – a high-security
business park on the remaining piece of empty land adjacent to the airport. Airport City
was launched in 2002, with the first section (Phase 1) already serviced, security fenced
and selling fast.
One of the
future phases of Airport City presently consists largely of the 20ha rubble tip. In order
to build, the land needs to be levelled, the huge piles of waste material removed and the
surface stabilised. With one of the newest and most elaborate crushing and recycling
plants in the Western Cape, Bradis Crushing & Recycling (Pty) Ltd has started to
tackle the estimated 800 000 m3 of rubble, some of which has been there for 25 years.
Their mission is to recycle the mountains of stone, reinforced concrete, brick and scrap
steel to create a variety of useful building materials, and the levelling of the land for
the future business park. The company holds a three-year contract. Work started in June
last year.
The plant
crushes and sorts materials into recycled aggregates and, at present, produces around
800m3 a day of materials ranging from fine reclaimed topsoil to chunks of masonry. The
products in most demand are those aggregates used for road construction – the base
course material known as G4 base and a finer gravel called G5 sub-base. One of Bradis’
first customers was the civil contractor of Airport City, with the construction of the
business park’s many roadways and parking areas, a large tonnage of both base and
sub-base was required. Other customers include the surrounding urban developments and
involve roadworks for the improvement of the informal settlements and the nearby low-cost
housing schemes. Philippi, Gugulethu, New Cross¬roads, Delft and Mfuleni have all been
supplied with recycled aggregates from the Bradis crushing plant.
These
recycled aggregates are extremely cost-effective, at about half the price of delivered
primary virgin aggregates – which have to be quarried from natural rock, crushed and
transported for long distances to construction sites. The use of recycled materials is
saving local government considerable amounts and it is putting into practice the
principles of sustainable development, advocated by central government’s waste
policy, by minimising the use of natural resources and promoting reuse and recycling.
Bradis has
also opened its operation to a small army of self-employed salvage workers. In the wake of
the excavators, these men and women pick through the newly exposed rubble for whole bricks
and scrap metal. The bricks are cleaned up, neatly stacked and sold for 40 cents each to
budget home builders. Metal is sorted and sold to metal scrap dealers for cash.
When the
recycling project reaches its conclusion in several year’s time, there will not only
be a well-consolidated surface for the new business park – but a small park
comprising a 2-3ha strandveld sanctuary and reinstated wetland which is planned as part of
the Airport City development.
Contact Storm Durr ceo of Airport City Property Holdings: Tel: 0800 202 878. Email:
storm@airportcity.co.za or William Dix, Bradis
Crushing and Recycling’s project manager: Tel: 9021) 386 5050. Email: bradis@iafica.com
‘Chameleon
Action’ Environmental Law award
Prominent
Durban law firm Garlicke & Bousfield has presented Sarika Maharaj with the
Environmental Law prize for 2003. The firm has been making this award to the top student
in Environmental Law at the University of Natal for the past 10 years. Sarika has been
awarded the prize for her work on the project ‘Chameleon Action’. This involved
research into the threat to the dwarf chameleon, Bradypodian Melocphalum, an endangered
species which is endemic to the Umbilo River area. The only three known localities of the
chameleon are along the banks of the Umbilo River in Cato Manor.
In 2002 the
area was rezoned for an office park, but when the possible extinction of the dwarf
chameleon became known, the developers agreed to rethink their proposal. An area along the
banks of the Umbilo was allocated to conserve the chameleon. Chameleon proof fencing was
erected and all the dwarf chameleons in the Cato Manor area were relocated to the new two
hectare ‘chameleon park’ during August 2002. Its official name is the Durban
Metropolitan Open Space System (D’Moss) Chameleon Reserve.
Natal
University’s Professor Jeremy Ridl said: “The capture was a difficult task
carried out by volunteers from WESSA and the students working on this project. The
chameleons are about the size of a R2 coin and are nocturnal so they can only be captured
at night with a flashlight which picks up their blue glow. The project has been successful
and the dwarf chameleons have escaped extinction, which would certainly have resulted from
man’s development of this piece of virgin land.”
Sarika was
the leader of a team of eight students and according to Professor Ridl she was a clear
winner out of the 70 participating law and science students. Peter Slack of Garlicke &
Bousfield said that the award was made annually to an undergraduate student who was
selected partly on marks gained in the assignment, but also on exam results and the
student’s contribution in class. Sarika who is currently working on her LL B said her
choice of career was made to allow her to represent the land and the animals, as these
were without knowledge or understanding of the law. “I believe that environmental law
and environmental sciences should be taught in schools so that future generations will be
able to care for their surroundings and to promote economic and environmental
sustainability.”
Contact Kirsten Youens of Garlicke & Bousfield. Tel: (031) 570 5300. Email:
kirsten.youens@gb.co.za
Zoo Lake’s
Coronation Fountain restored
The Zoo Lake
Users Committee raised R300 000 to restore Zoo Lake’s historic Coronation Fountain
(see article on proposed restoration in Jul/Aug 2001 UGF) and the synchronised coloured
lights are once again in working condition. The original plaques on the side of the
fountain, one in English and one in Afrikaans, have been restored and once again depict
the old crest of the City of Johannesburg and relate that: “This fountain was erected
to commemorate the coronation of their majesties King George VI and Queen Elizabeth. 12
May 1937.” Councillor Donald W Mackay was the Mayor at the time and his name appears
on the plaques, along with I Marks who was the town clerk.
Lucy Taylor
of the Zoo Lake Users Committee spearheaded the fund raising drive and she pointed out
that Zoo Lake was the only park in Johannesburg that had always been open to people of all
races even during the apartheid era (see history of Zoo Lake in Jul/Aug 2001 UGF). She
said the restoration work could not have been completed without the funds provided by the
City’s Department of Arts, Culture and Heritage, but that City Parks had also
contributed a sum, as had Societé Generale (their contribution was specifically for the
lights) and the Oriental Plaza. She said money from the Save the Zoo Lake fund had been
accessed and that the community had also contributed to reinstate their heritage.
The Fountain
is of cultural significance to the people of Johannesburg because of its historic,
aesthetic and social value. Architect Henry Paine responsible for the restoration
emphasised the need to retain both materials and craftsmanship in a restoration project
but added that some changes had to be made for the sake of maintenance.
Speaking
about the choice of colour for the fountain, he said that seven or eight layers of
different coloured paints had been stripped off by the workmen, from swimming pool blue to
dark green, with no colour predominating. It had been necessary to choose a
maintenance-free solution and the most hard-wearing paint type suited to the purpose of
the structure had only been available in two colours. The muted biscuit colour had clearly
been preferable to the grey-brown option. He commented that the grimy colour of the
encrusted algae had predominated for years but that a repeat of this had now been
precluded by a special silicon sealant between the bronze lip and the concrete structure,
which would stop the water from running down over the surface of the paint and leaving a
residue of algae.
The level of
the water in Zoo Lake was lowered to allow the paint to be removed and a dry ice method
was used to freeze the paint, as this creates mechanical attrition and, literally, knocks
the paint off the structure. Paine said this method was chosen because it did no damage
and chemicals could not have been used because of the proximity of the water. He said that
the lake water had again been lowered when the painting was being done. Divers were used
to do the underwater work and an unsafe concrete maintenance platform was removed from the
side of the structure. The concrete platform was replaced with a stainless steel landing
stage.
It was
discovered that the pumping chamber had leaked and the motor and switchgear had been
submerged and the latter had to be replaced, while the motor was rewound. Paine said City
Parks had taken responsibility for this unforeseen event. The mesh fish trap had fallen
off and this was replaced with a new stainless steel box. A seamless skin of waterproofing
ensured that the pond was sealed off and there was no water pressure on any joints, as
these potential weak points were all above the surface of the water.
The original
light fittings were retained after some restoration work and Paine maintained that the
workmanship was so good that there was no reason that the fittings should not last
indefinitely. The old 4 000W General Electric bulbs, imported from America, were replaced
with 220 volt halogen lights with 1 000W bulbs, which reduced the power required to run
the lights by a factor of four. Spares of the coloured perspex lenses were still in
existence and these were fitted to the lights, firmly fixed with copper clips. As the
spouts of the fountain change form so the colour changes, from green to red to white, as
it did originally.
Paine
commented that the main contractor Revamp, a well known company which has specialised in
restoration work for many years, had done an excellent job.
Contact Lucy Taylor of Zoo Lake Users Committee. Tel: (011) 726 27 84. Email:
taylor.fam@pixie.co.za
Environmental
awareness programme in Sekhukhuneland, Limpopo
During the
environmental rehabilitation of the Lebalelo pipeline (see Jan/Feb 2002 UGF) in
Sekhukhuneland in 2001 and 2002, the environmental facilitator Jeremy Stubbs, funded by
the Lebalelo Water Users Association, organised training for local people along the
principles of land use management and understanding of the environment. Fifteen
facilitators were trained to go into neighbouring villages to cover aspects such as the
prevention and treatment of soil erosion, rehabilitation, sustainable harvesting of
firewood and muthi plants and other environmentally sound practices.
To help
carry this environmental awareness and education programme further, in June 2002 Stubbs
formed the company Masole a Tlhago (Soldiers of Nature) environmental services with a
shareholding of 55% for Lazarus Mokwena who had been sourced from the company Educate
Develop and Learn for Life (EDL) and had served as the lecturer for the original training
programme. The new company planned to continue with both rehabilitation work and the
environmental education programme for villages and schools.
In August
2002 Anglo Platinum’s socio-economic department agreed to fund the programme for four
months with the focus on facilitation. EDL drew up a monitoring and evaluation sheet so
that measurable results could be provided. Stubbs wrote the ‘Handbook for the Manual
Rehabilitation of Disturbed Areas’. Mokwena and three facilitators addres¬sed both
environment and poverty to attempt to change the mindset of the local people, so as to
give them hope and encourage self-help.
Local
village committees were formed and community gardens were established at a number of
villages where water was available, with the advice and encouragement of Masole a Tlhago’s
facilitators. The committees were encouraged to work along the lines of traditional
subsistence agriculture and subsidised seedlings were bought from the Anglo Platinum
community centre.
The village
and school environmental awareness and education programme now falls under the direction
of the social office of Twickenham Mine which means that it is concerned with the
communities which serve the mine.
Soil erosion
Masole a
Tlhago also provided training in the rehabilitation of areas affected by soil erosion and
the Motlolo stone walls project was born. Anglo Platinum paid a group of villagers a daily
basic wage to install antierosion measures. Masole a Tlhago managed the project and
trained the people with the involvement of the local extension officer. The village was
chosen because there was serious soil erosion in evidence and because the local people had
shown signs of real interest in the project.
Stubbs
commented that losses of up to 60 tonnes of topsoil per hec¬tare per annum were being
experienced in Sekhukhuneland because of the over-utilisation of land in this dry area and
inappropriate farming practices.
The work at
Motlolo which started after a three-day intensive workshop led by Mokwena was based on dry
packed stone walls and was labour intensive. A tractor and trailer to help cart the stones
was hired from a local farmer out of the budget for the project. Stone walls were
constructed across dongas down the sides of roads, with the stones keyed into the sides of
the donga and with a freeboard shoulder on either side of the centre portion which had to
be exactly level. This is to create an even spread of water and prevent channeling. The
construction was started at the head cut.
Only local
resources were used and gabion construction was avoided because of the possible theft of
the wire. The dongas began to silt up after the rains and the village people were able to
understand the principle that their work had been based on and take pride in their
labours.
Contact Jeremy Stubbs – Tel: (011) 234 1735 or Lazarus Mokwena – Cell: 072 425
2155
Gabion building
competition
Seven
contracting teams from the North West and Gauteng regions of the Working for Wetlands
programme, part of DWAF’s Working for Water initiative, competed against each other
in a gabion building competition at the Colbyn wetland (see Jul/Aug 2000 UGF) in Pretoria,
earlier this year. The week-long competition was judged and sponsored by African Gabions,
who were also responsible for the initial training.
The
competition was judged in two phases. The first phase judged by Amelia Maree took into
account the health and safety standards of the respective teams; while the second phase
which was judged by managers Gary Matthews and Dale Chaychuk, with the support of David
Ntuli and Paul Molapo from African Gabions technical department, looked at the quality of
the gabion construction and the timeframe in which the structures were built. The teams
were organised by Stefan Kruger and Roger Brown of Working for Wetlands.
The
structures were positioned by Working for Wetlands with the objective of rehabilitating
the eroded wetland and the small area of peatland by raising water levels. The gabion
structures will cause water to spread out across the extent of the wetland and to push
back up towards the head cut above the peatland to ensure that the peat is kept
permanently wet. The teams were given training in gabion construction by Ntuli and Molapo
and they were required to read a plan – something they were not really familiar with.
The competition served as an excellent learning exercise and the judges spent time
pointing out mistakes and relating how improvements could be made. There is a possibility
that this will become a national competition in future.
Piet-Louis
Grundling of Working for Wetlands said at the award ceremony that a good job had been done
at short notice over a short time period. He said the competition had been a good
challenge for both contracting teams and Working for Wetlands’ stores staff who had
had to source and deliver the right quantities of materials to the Colbyn site at the
right time. He said the work rate of the construction teams had exceeded that of the
average work rate of Working for Wetlands teams. Matthews, African Gabions’ regional
manager for Gauteng and one of the judges, announced the winners saying that it was
important to understand the vital need to repair wetlands. He said such gabion structures
had to cope with a lot of water and that they had to be built with great care so that they
performed well.
The third
prize was won by Erasmus Construction from Kaalspruit; the second place was taken by Bheki
Msezane’s team from Soshanguve; and the first prize went to Margaret’s
Construction from Rietvlei – who although they were handicapped by the depth of their
structure in the streambed and the effect of the water, which influenced the time taken to
complete the structure, made up for this by their excellent site control and health and
safety standards.
Contact Roger Brown, technical manager, Working for Wetlands. Cell: 082 358 8712. Dale
Chaychuk of African Gabions: 082 806 4628.
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IDENTIFYING INVADERS
Pickerel Weed and Honey Locust
UGF’s regular column to help with the
identification of invasive species that are listed in the amended regulations of the
Conservation of Agricultural Resources Act.
Pontederia cordata
Pontederia
cordata – the Pickerel Weed – is a declared invader, category 3. It is a rooted
aquatic plant, 1-2m in height, which forms colonies. The blue flowers occur in spikes and
the plant is used as an ornamental in water features. It invades riverbanks and drainage
lines and is a special effect weed which can significantly degrade natural ecosystems.
“No
land user shall allow category 3 plants to occur within 30m of the 1:50 year floodline of
a river, stream, spring or natural channel in which water flows regularly or
intermittently – lake dam or wetland.” Because it is a category 3 invader, it
may not be propagated, sold or planted but if it was already in existence in a garden
water feature at the time of the commencement of the amended regulations it need not be
eradicated, as yet.
Gleditsia triacanthos
Gleditsia triacanthos – Honey Locust – is a declared invader,
category 2. There are apparently sterile cultivars of this tree and these are excluded
from invasive status. It is a spreading tree, 15-20m tall which is cultivated for honey
production, shade and donga reclamation. Its trunk and branches are armed with formidable
single to three-branched spines and its distinctive large pods are dark reddish-brown,
shiny, twisted or flattened. It invades grassland, savanna, roadsides and riverbanks. It
is a potential transformer and is already invading natural habitats with the potential of
dominating a vegetation layer but not yet having a marked effect in South Africa, although
it is elsewhere in the world. Because it is category 2, it may be cultivated under
controlled circumstances in a demarcated area for honey production – but otherwise
needs to be removed. There is no herbicide registered for the plant which should be
controlled mechanically with young saplings being pulled out by hand.
Most of the
information in this column is extracted from Lesley Henderson’s book ‘Alien
Weeds and Invasive Plants’. Contact the National Department of Agriculture for
further information: Email: declaredweedsandinvaders@nda.agric.za or Working for Water’s
Weedbuster Hotline: 0800 005 376.
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BOOK REVIEWS
‘South African Weather and Atmospheric Phenomena’
Author:
Dries van Zyl
Publisher: Briza Publications
Another of
Briza’s attractive publications which can be used as the equivalent of a ‘field
guide to weather’ in South Africa, because it is extensively illustrated and provides
the layman with just the right amount of scientific data, expressed concisely and in a
very readable format. Van Zyl sees his readership base as being those interested in ‘landscape
meteorology’which has been defined as ‘those scenic influences of sky,
atmosphere, weather and climate which form part of our natural environment.’ The book
emphasises a natural weather experience in the context of landscape meteorology, rather
than the abstract modelling of weather processes. The book is aimed at weather enthusiasts
whether they be travellers, photographers or farmers. It contains over 200 of Van Zyl’s
magnificent photographs of weather against a backdrop of the South African landscape.
Van Zyl grew
up on a farm and there he developed an early appreciation of the vagaries of weather which
translated into a life-long interest in natural phenomena. He is also an award-winning
landscape and weather photographer and his pictures have featured in local and overseas
publications. He specialises in scientific software development and while employed by the
CSIR, he created software to transfer Meteo-sat weather satellite images onto map
projections. He is a member of the South African Institute of Physics.
The first
part of the book features subjects such as climate, forecasting, thunderstorms and
detailed descriptions of types of lightning, cold fronts, rainfall and a section entitled
‘cloud atlas’ which gives the basic cloud forms and then goes on to describing
these using their generic and specific scientific names, describing each of the more
common cloud types and illustrating these with a series of photographs which can be used
in their identification. More than 400 cloud types are recognised today. One of the more
common of our South African cloud types in the summer rainfall regions is the huge dense
cloud with a dark base, called Cumulonimbus and this causes most of the damage associated
with severe thunderstorms, through wind gusts, lightning, hail and flash floods.
The second
part of the book is about optical atmospheric phenomena. The dispersion of sunlight into
its component colours by water drops and ice crystals in the atmosphere creates a host of
spectacular phenomena such as rainbows and fogbows, sundogs, solar and lunar coronae, sun
pillars and the circumzenithal arch, which are all illustrated by superb photographs.
A series of
fascinating facts about weather and atmospheric phenomena is recorded throughout the book.
These are a
few examples.
*
In central Africa
thunder is heard on an average of about 150 days a year, whereas in most of Europe it is
heard on only about 11 days per year. In and around Johannesburg thunder is heard on 50-60
days per year and in the Cape Peninsula only about 12 times a year.
*
The current flowing
during the return stroke of a lightning flash superheats the air to 22 000°C, more than
four times hotter than the surface of the sun, so fast that it has no time to expand and
this produces a shockwave, a major disturbance in the air travelling faster than the speed
of sound. It compresses the surrounding air and soon decays into an acoustic wave,
creating a loud thunderclap heard up to 30km away.
*
Keeping your heels
close together minimises the effect of the ground current generated by a nearby lightning
strike.
*
In low rainfall
regions such as the Namib, advection fog transports moisture from the ocean up to 50km
inland and sustains highly adapted forms of insect and plant life.
*
Death usually occurs
if the brain temperature rises to 42°C. Gemsbok do not need drinking water to maintain
normal body temperature. They possess a remarkable temperature regulation mechanism that
keeps the brain cool when blood temperature rises on very hot days in the Kalahari.
Cooling of the blood before it enters the brain is effected by an arterial network
utilising evaporation of moisture in the nose.
*
Also known as a white
rainbow or mist bow, a fogbow is a pale white rainbow of low contrast and wider than the
2°C of the normal rainbow. Large drops produce more vivid rainbows, while with smaller
drops diffraction occurs. Wave interference dominates, causing colours to overlap and
become white.
*
Coronae are coloured
concentric rings a few degrees across around the sun or moon, seen through thin clouds
such as Altocumulus. The central white disc is the aureole. Coronae are formed by the
interference of light diffracted around the outside of water droplets.
‘Making the
Most of Indigenous Trees and Plants’Revised Edition
Authors:
Fanie & Julye-Ann Venter
Main photographer: Pitta Joffe
Publisher: Briza Publications
This new
edition of a very significant book which has been used by gardeners, naturalists,
nurserymen, farmers, foresters and conservationists, countrywide, features seven
additional tree species and a more accessible arrangement of the trees according to their
botanical names. More than 140 trees are discussed in detail providing information on
diagnostic features, flowering and fruiting periods, natural distribution and habitat; the
trees ecological role – utilisation by mammals, birds and insects; use by people
including use in the garden and as a source of food for humans and animals; amongst other
aspects. More than 750 colour photographs complement the text showing the architecture of
each tree and close-ups of flowers, fruit, bark and leaves.
‘Poisonous
Plants of South Africa’
Authors:
Ben-Erik van Wyk, Fanie van Heerden and Bosch van Oudtshoorn
Publisher: Briza Publications
This book is
a comprehensive photographic guide to the most commonly occurring poisonous plants in
South Africa – indigenous and exotic plants that cause human and animal poisoning.
The book gives detailed species descriptions of 135 poisonous plants that occur in the
wild or are grown in gardens. Each entry includes the following information: a description
of the plant, the type of toxin, the potential toxicity of the plant and its role in human
or livestock poisoning; the poisonous ingredients and their pharmacological effects. This
a reference guide for health professionals, veterinarians, farmers, gardeners and amateur
and professional botanists.
Plants have
devised cunning chemical defence systems to deter plant eating animals and sometimes even
to kill them. Most human fatalities occur when poisonous plants are mistaken for food
plants. According to statistics of the poison unit of the Johannesburg General Hospital,
plants are responsible for about 6,5% of all poisoning cases with some of the major
culprits in the Johannesburg municipal area being Syringa berries (Melia azedarach –
category 3 invader), Oleander leaves (Nerium oleander – category 1 weed) and
Poinsettia latex (Euphorbia pulcherrima).
Contact Briza Publications. Tel: (012) 329 3896. Fax: (012) 329 4525. Email:
info@briza.co.za. Website: www.briza.co.za
-----
TREE OF THE ISSUE
Graeme Leitch chooses Berchemia discolour
Brown
Ivory
Graeme
Leitch of Leitch Land¬scapes in KZN has chosen this month’s Tree of the Issue. He
has chosen a ‘new’ tree for commercial/office landscapes in KZN – a tree
that is not being grown commercially that he believes would make a good ornamental subject
for the larger landscape. He has started to grow Berchemia discolor for use in Leitch
Landscapes’ projects based on observation of these trees in the wild on the
Mozambique coast – and on having used another of the same genus, Berchemia zeyheri
(Red Ivory), in his landscaping around the ministerial housing at Ulundi.
Initially,
he battled to get seed of the Brown Ivory but eventually got some from Silverhill Seeds in
Cape Town and now has about 50 small trees in his nursery. The trees are in 2l bags out in
the full sun and are not being given any special treatment so as to prove their hardiness.
He sees the
tree as being a good addition to what landscape architects term the “forest matrix”
– which involves drawing clusters of indigenous trees of all sizes into office parks
to give the feel of a continuation of natural woodland. B. discolor is a large, shade
giving tree which can reach between 15-20m in height and is better suited to this kind of
landscaping than its counterpart, B. zeyheri, which Graeme considers to be a nice tree but
rather small, and he has found it to be somewhat slow growing.
“The
Brown Ivory brings in a number of different characteristics such as attractive round
leaves of which the upper and lower surfaces are a different colour (that is why it is
called discolor). The leaves are glossy, apple-green above and a much lighter contrasting
green on the under-surface. The tree’s grey, segmented bark adds a different
dimension. It will blend in with other trees commonly used in forest plantings and yet it
has a different character. Trees used in this kind of landscaping to create a wild feel in
between rather stark office buildings have been a mixture of different Ficus species,
Trichelia dregeana (Natal Mahogany), Rauvolfia caffra (Quinine Tree) and a variety of
acacias and Cussonia species. I am hoping to introduce the Brown Ivory into the
developments of Gateway and Umhlanga Ridge at Umhlanga Rocks,” says Graeme.
Graeme
points to another favourable aspect of the tree which is that it is verging on evergreen
and although there is a percentage of leaf loss in winter which serves to let the sunlight
through, yet its appearance is always that of an evergreen tree. He says the tree should
not only be considered for the so called “forest matrix” situation but as a
single specimen on lawn in parkland because of its attractive shape and shade value. He
has observed that it favours the drier, well drained conditions slightly inland of the
coast in Mozambique, although it grows right up to the sea both there and on the KZN
coastline as well. He says this could be a family characteristic as he believes the Red
Ivory planted at Ulundi could be suffering from over-irrigation.
Another
important factor, Graeme points out, is that B. discolor’s root system is not
aggressive and it can be planted up against buildings and near pathways with safety. He
adds that he is sure the birds in Umhlanga “will be wildly excited” because they
love the fleshy, yellow, ripe fruits.
The start of
a new project and one Graeme hopes will not disappoint him.
-----
FEATURES
Gas from waste – an energy source
The
Ekurhuleni Metropolitan Municipality (EMM), which governs the East Rand in Gauteng, has
implemented an innovative pilot project in which methane gas is extracted from landfill,
purified and put to use as a fuel in refuse collection trucks. Tony Pieterse, interim
executive manager of the Municipal Infrastructure Department at the EMM, spoke to Urban
Green File about the pilot project and the Metro’s current investigations into its
potential for broader implementation. Methane can be used not only to power vehicles but
also to generate heat and electricity.
All landfill
sites generate methane – one of the gases that contribute to the depletion of the
earth’s ozone layer. At present in South Africa, landfill operators are legally
required only to monitor methane levels four times a year and to maintain them within a
stipulated range that allows for control of explosion and fire risks. Under this regime,
potential problems can be detected and dealt with appropriately, but the methane is
neither destroyed (before it destroys the ozone layer) nor put to good use.
Through its
methane pilot project at the Weltevreden landfill site, the EMM has chosen a route of
actively managing this by-product of waste. Although to date this is operating only on a
pilot scale it points to potentially significant benefits in respect of the environment,
landfill management efficiencies and cost savings.
Methane extraction from landfill
Pieterse points out that there are a number of advantages simply in extracting methane
from landfill sites: it promotes quicker settlement of the waste dumped, so providing more
airspace and promoting more efficient use and a longer lifespan for the site.
Typically,
Pieterse explains, waste is dumped to landfill on a daily basis, compacted and, at the end
of the day, covered with a layer of soil. In this way the landfill grows in ‘cells’,
until it reaches a maximum allowable height of 25m across the site, when it is closed and
sealed with impermeable clay.
Methane can
also be extracted from operational and already closed and contained landfill sites. The
advantages of drawing the gas off closed sites and using it as a fuel or energy source, is
that it reduces the volume of the containment and re¬duc¬es the waste risk of the
contained site, as well as benefiting the environment by reducing the amount of methane
released into the atmosphere.
The question
is: what is to be done with the methane extracted?
Applications
Methane is a source of energy that can be used to fuel vehicles, to generate
electricity and to produce heat for domestic use or in industrial applications such as
cement and brick kilns which have a high heat demand. In Europe and Britain the practice
of extracting methane from landfill is widespread (at more than 100 sites in England
alone) and the gas is used primarily to produce electricity, as well as for heating and to
a much lesser extent as a fuel for vehicles.
On contained
sites, methane can also be flared. Flaring is practised at only two known sites in SA
– one outside Durban and one in Pietermaritzburg where wells have been drilled into
the sealed dump and methane is actively forced out of the landfill and burnt off. While
this at least contributes to reducing ozone depletion, it ignores the potential
applications of the gas and is, in effect, wasteful.
Weltevreden pilot
project
In 1999 the then Eastern Gauteng Services Council commissioned the former
Atomic Energy Corporation to supply and install a small-scale pilot methane purification
plant at its Weltevreden landfill site at a cost of R558 000. The project was implemented
to determine the viability of using methane as a fuel for the Council’s refuse
collection vehicles.
The
installation comprises a purification plant, a cylinder storage facility and a fuelling
pump, as well as pipework and controls.
Methane is
extracted from only a small section of the landfill, about 150m by 200m in area, just 10%
of the volume of the heap. The extraction system functions passively. When the storage
cylinders are empty the system kicks in automatically to draw gas out of the landfill,
through the network of plastic pipes, to the purification plant. The gas is processed to
eliminate its odour and reduce the fire risk – producing a 90% pure methane. It
transfers passively to the storage cylinders and from there can be drawn off via the pump
station to fill the gas cylinders that are mounted on the roofs of the refuse collection
vehicles.
Since the
project began, EMM has operated and continues to operate four refuse collection vehicles
using a 25% diesel : 75% methane fuel mix. The engines of the trucks have been modified to
use this fuel – which has the advantages of being considerably cheaper than diesel
alone, producing cleaner emissions and imposing a lower level of wear and tear on the
engines. Savings of between R25 000 and R35 000 have been achieved per vehicle per year.
There are
some drawbacks. Pieterse says that because the rate of compression in the engine using
methane is slower than that afforded by conventional fuel, the vehicles lose some power.
This becomes problematic when there is an especially high power demand – as when the
waste has to be compacted on the trucks.
There are
also problems with spare parts because the local market for these specialised components
is so small they are not made in SA but are imported, so the turnaround on replacement
parts is delayed.
In Pieterse’s
view the problems that have been encountered with the vehicles in this pilot project can
be readily overcome. He emphasises that the use of methane from landfill sites has to be
recognised as essential in the long term – and the EMM’s success with its
small-scale, short-term project is an indication that processes and technologies can be
developed and refined to optimise the use of methane in various applications.
Next steps
The Development Bank of Southern Africa, which has taken a close interest in
the pilot project and contributed to its ongoing operation and maintenance, has recently
given a grant to the EMM to undertake a fact-finding tour of plants in Europe and England.
This will serve to inform a feasibility study that will investigate if and how methane
from the landfill sites within Ekurhuleni can be put to use. A team from the EMM is
shortly to embark on this tour.
“Obviously
the conditions in Europe differ from ours here,” says Pieterse, “but we will be
able to gain a first-hand understanding of the technologies and processes that have
already proven viable there. Then we can look at adapting them to suit our needs at home.”
Following
the fact-finding mission, the EMM plans to commission consultants to evaluate how much
methane it can source from its landfill sites. The Metro currently operates five landfill
sites – each with a methane-generating lifespan of between 30 and 40 years. A sixth
landfill site is planned but not yet developed. And there are a further five closed sites
in Ekurhuleni that will continue to generate methane for another 20 to 30 years.
Various
factors affect methane generation from landfill: the types and mix of waste, the
acid/alkali balance of the waste material, the density of compaction and, perhaps most
significantly on the South African highveld with its dry winters, the moisture content in
the atmosphere which needs to be around 25% for methane to remain stable. Pieterse reports
that even at the scale of the pilot plant there has been a decline in methane production
over winter months.
If the gas
were to be used on a wider scale, in the generation of electricity or heat or as a fuel,
some means would need to be found to maintain a constant level of atmospheric moisture at
landfill sites and in the processing system. As Pieterse points out, water and waste are
seldom a good mix because the higher the proportion of moisture in landfill waste
(typically not more than 20%), the greater the risk of contaminated water leaching through
liners to surrounding land and groundwater. This is just one of the concerns to be
investigated in the tour of methane fuel plants abroad.
By mid-year,
the Metro expects to have a measure of the methane generating capacity of its landfill
sites and, accordingly, a range of options on how such capacity can be put to use, viably
and sustainably.
The EMM is
already considering potential markets for methane-generated electricity – to supply
power to council-owned buildings, for example – and for methane-fuelled heating in
local industry. However, the practicalities, as well as management, cost and risk
implications of such options remain to be assessed.
Costs for
degassing – or for extracting gas from landfill sites – range between R6 million
and R8 million per site, according to Pieterse. Currently, operational costs (excluding
capital costs) at the Ekurhuleni landfill sites range between R5 million and R8 million
per site, per year. So, although the capital costs for degassing are quite high, Pieterse
argues that these costs would be amortised over time if the methane were used as a
substitute for conventional heating fuels or electricity supply. EMM is also looking at
the opportunities presented by the Clean Development Mechanism, formulated in the Kyoto
Protocol, which could enable it to obtain international funding in a proportionate
exchange for consumption of methane (eliminating the gas’s impact on the ozone layer)
or for the supply of clean, ‘green’ electricity instead of coal-powered
electricity.
-----
Phytoremediation of nickel
contaminated soil
Project
at Rustenburg Base Metals Refiners
Carol Knoll
interviewed Kerry Slatter, a biometallurgist at Anglo Platinum’s Research Centre,
about the remediation of nickel contaminated soil adjacent to the company’s base
metal refinery outside Rustenburg. The remediation is being done with an unimposing
species of the daisy family which is endemic to the serpentine outcrops of the Barberton
district. Berkheya coddii has the extraordinary ability of accumulating nickel in its
stems and leaves. Slatter did her Masters in Biochemistry on Berkheya coddii as part of
the investigative work done by Anglo Platinum. The project which started in 1995 is
on-going and Stewart Whyte of Anglo Platinum’s Rustenburg environmental department
provided updates on the current status of this initiative.
Phytoremediation
is the removal of toxic metals from a site using plants that are able to tolerate those
conditions and to accumulate a specific metal to at least 0,1% in their dry material.
These plants are known as hyperaccumulators and they are limited in the natural
environment to serpentine soils where a high level of mineralisation occurs. There is no
certain scientific explanation (although there are hypotheses) for why the plants have
this ability to transport and concentrate metals in their aerial parts, but use is being
made of these plants world-wide to retrieve metals from soil, by planting and harvesting
these plants, usually for the purpose of rehabilitating polluted soils.
The process
is far less expensive and more environmentally sound than alternative, more conventional,
remediation measures such as vitrification or excavation and leaching. Acid leaching of
nickel leaves the soil sterile, whereas with phytoremediation soil fertility is retained.
Phytoremediation is cost-effective, as once the soils are cleaned they become arable
again.
Rustenburg
Base Metals Refiners (RBMR) has been operating for nearly 50 years in a semi-rural area in
the North West Province, processing metals from the platinum group, along with copper and
nickel. Anglo Platinum’s environmental policy includes the need to remediate
contaminated soils and at RBMR various areas around the plant, amounting to several
hectares, were in need of remediation as a result of years of deposition of base metals.
Today, this continued contamination is something of the past as the effluent now flows
down concreted channels into lined dams.
During the
1980s, Berkheya coddii was brought to the attention of researchers at Anglo Platinum (then
known as JCI) who were looking into effective ways of remediating soil. In its natural
environment, the species is able to absorb from the soil and store over 3% of its dry body
weight in nickel. The nickel is stored in an inert form in the vacuoles of the plants
aerial parts. B. coddii is endemic (found nowhere else in the world) to the serpentine
soils of the Barberton area in Mpumalanga. While there are other nickel accumulating
plants, B. coddii is the only significant one indigenous to South Africa and, fortunately,
also the most efficient globally. The plant is voracious in its bioaccumulation of nickel
which is taken up by its extensive root system – even when the acidity of the soil
does not completely favour absorption.
Kerry
Slatter’s thesis served, amongst other aspects, to determine the natural growth cycle
of B. coddii at Barberton and its nutrient requirements, in order that growth and nickel
uptake could be maximised, and it dealt with the likelihood of the plant’s long term
survival on the soils of Rustenburg, when it had evolved on Barberton’s dark
serpentine soils. Slatter was also required to develop a method for removing the nickel
accumulated in the above ground biomass, once the plants had been harvested from the
designated sites at RBMR. The practical aspects of the project were carried out by RBMR
staff under the supervision of Andrew Howes and monitored by Slatter.
The plant
produces thousands of seeds but these have a short life span. An appropriate potting mix
comprising soil from RBMR, vermiculite and Barberton’s serpentine soil was developed
and the plants were grown in speedling trays with five seeds in each compartment. The
seedlings were transplanted into 1l bags and then into sample areas of contaminated soil
at RBMR. Three areas were planted up under irrigation in 1995, to the same density as the
communities found in Barberton. After the first year it was discovered that planting
densities on the contaminated soil needed to be increased.
The plant is
perennial, flowering from December to March and dying back at the start of the dry season
only to resprout again at the commencement of the wet season and has, therefore, the
economic advantage of not having to be replanted every year. The first crop was harvested,
after the seeds had been collected manually, in May 1996 – the first season after
planting. The partially dry biomass (stems and leaves) was collected and dried further in
the sun. The nickel was extracted by ashing the plant material and oxidising the ash. The
nickel was leached from the organic material and converted to metal form in an induction
furnace.
With
approximately 25 000 plants growing on the three hectares of experimental plots, Anglo
Platinum retrieved about 1kg of nickel per ha in the first year – symbolic 50 gm
nickel buttons were produced as proof of success. These initial results were so promising
that Anglo Platinum increased the size of the planted areas in the following season and
the density of plants was increased, through filling in with new plants grown from the
seed of the experimental crop. The small parachute seeds can be harvested once the plant
dries out and they need to be planted within four months to give them the best chance at
germination.
The present
density is about 10 plants per m2 and the species has clearly adapted to the
new soils fairly easily. Slatter reported that a hailstorm had wiped the plants out during
the first year but they had all sprouted again within three weeks, proving that the plant
is both hardy and adaptable.
Slatter said
that in 1996, the RBMR project was the first large scale industrial phytoremediation
project in the world.
An important
characteristic of B. coddii is that it is, like most serpentine flora, unable to compete
with other plant species. Slatter pointed out that veld grass encroaching into the planted
sites at RBMR had to be re-moved to ensure the growth and spread of the non-competitive
Berkheya. This characteristic means that the plant cannot become invasive in its new home,
as it cannot move into any new area where there is plant cover. Also, it is the nickel in
the soil which is necessary for the growth of the plant that will keep it growing on the
soils at RBMR – and once this nickel is depleted, the plant will die back permanently
and the natural vegetation of the area will return to the sites. Slatter reported that no
Berkheya seedlings had been found growing outside of the demarcated zones over the seven
years that the project had been underway.
This is a
long term project, expected to take between 15-20 years for a satisfactory clean-up.
Bioaccumulation initiatives of this nature represent a relatively passive measure of soil
remediation that is generally financially feasible and well suited to the post closure
stages of industrial and mining operations. Stewart Whyte said that a walk-away policy
would probably not be possible as the plantings would clearly need some maintenance on an
on-going basis. On an experimental basis in 2002, irrigation and fertilising of the
Berkheya communities was curtailed, so that the plants were dependent on rainfall, and the
results were not entirely satisfactory as the crop was considerably reduced in size. This
could have been as the result of a very dry season in 2002. Further trials will be
undertaken to determine the main requirements of the crop.
According to
Whyte, it is a reasonable assumption that the project will take somewhere in the region of
15 years – based largely on varying climatic factors such as higher evaporation
bringing more nickel salts to the surface where they are available to the plants, and
heavy rain leaching the salts deeper into the soil. Average nickel concentration in the
surface soils under B. coddii cultivation is approximately 0, 02 mg of nickel per kg of
soil, increasing to 0, 06 mg of nickel per kg of soil at a depth of 0, 5m, due to downward
leaching of nickel.
Weeding the
crop is an on-going necessity because the plants cannot tolerate any kind of competition.
The manual aspects of the maintenance are carried out by means of a community involvement
programme. Contractors Kobus and Regina Kriek provide the workforce which comprises a team
of about twelve local women responsible for weeding, fertilising, collecting seeds and for
harvesting and transporting the crop.
Slatter
commented that the plants had proved to be hardy with a fairly rapid growth rate and they
regrew as multi-stemmed ‘shrubs’ every season, increasing the biomass of the
crop. They had adapted completely to RBMR soils and proved to be a low maintenance, low
cost crop, with their winter dormancy allowing for annual harvesting. She went on to say
that the project was worthwhile from an environmental point of view and was not only
saving soil, but saving money, as excavation and removal of the contaminated soil to
landfill would have cost the company in the region of R8 million. She pointed out that the
proximity of Anglo Plat¬inum’s Waterval Smelter in which the harvested plants were
processed, adding (minimally only) to the concentrate of ore, was an integral part of the
project. She said that the small amount of nickel obtained from the plants was, however,
not economically viable and the project would come to an end when the nickel contaminated
soil had been remediated.
At the start
of the project in 1996, nickel uptake from RBMR soils was in the region of 1kg/ha,
increasing to approximately 5kg/ha in 1998 and thereafter levelling out at about 2kg/ha
over the past four years.
Whyte
explained that the observed decrease in nickel uptake in recent years was related to the
fact that initially there would have been an abundance of free nickel (bioavailable
nickel) in the soil and that this would have been assimilated relatively quickly by the B.
coddii plants, with peak uptake occurring in 1998, once the population was well
established. When this readily available supply of nickel had been depleted, the next
stage of nickel uptake would have involved nickel bound relatively strongly by the
clay-rich soils and the rate of uptake of this nickel would inevitably have been slower.
-----
Rehabilitation of strip mines
In
the arid environment of the Namaqualand coast
Report and
photographs by Kirsten Mahood of EFC Environmental and Forestry Consultants
Namakwa
Sands, a subsidiary of Anglo American plc, is strip-mining large tracts of the Namaqualand
coast for heavy mineral concentrate – ilmenite, rutile and zircon. The Namaqualand
coast forms part of a unique winter rainfall desert ecosystem and falls within one of the
biodiversity hotspots of the world. The region has many species of succulent plants of
which approximately half are endemic and therefore has a high conservation priority.
Strip-mining leaves large tracts of land denuded of all vegetation, often with soil
structure and fertility degraded.
Current
South African legislation requires that mines rehabilitate strip-mined areas to a form and
productivity equivalent to the pre-mining conditions of the site. The Namakwa Sands Team
has implemented various projects to facilitate the return of indigenous vegetation to
post-mined areas. One of these, a two-year MSc project through the University of
Stellenbosch funded by Namakwa Sands and the National Research Foundation, sought to find
out whether indigenous plant species could be transplanted onto post-mined areas.
In the past,
strip-mines have been saddled with a bad reputation because of poor rehabilitation or
because no land rehabilitation whatsoever has been done. Many mining companies are now
working to change this negative image of strip-mines. Namakwa Sands has been developing
new rehabilitation techniques to increase plant cover and biodiversity on post-mined
sites, thereby facilitating the revegetation process on post-mined areas, so as to achieve
a vegetation cover and productivity similar to the pre-mining land-use, which in this case
was small-stock farming.
Sand
strip-mining begins with the removal and stockpiling of all natural vegetation, organic
debris and topsoil from an area to be mined, leaving the sub-soil exposed. Stockpiled
topsoil is stored for use in rehabilitation. At Namakwa Sands the sub-soil is excavated
and sent to a mineral concentration plant for processing. Once processing of mined soil is
complete, processed soil (known as tailings) is returned to the pit from which it was
removed, in a process known as back-filling. Back-filled tailings are landscaped to blend
with the natural topography of the area and stockpiled topsoil is spread over the shaped
tailings, creating the surface to be rehabilitated. To reduce wind speed on the
rehabilitation surfaces, windbreak nets are erected, perpendicular to the dominant wind
directions. Mining operations move gradually from mined to un-mined areas in parallel
strips, hence the name “strip-mining”. The rehabilitation of post-mined areas
follows the movement of the mining operations, ensuring that a maximum of post-mined area
is undergoing rehabilitation at any one time.
The task of
rehabilitation is particularly difficult at Namakwa Sands as the strip-mine is located in
a harsh environment, with dry, hot summers, mild moist winters and a wind regime described
as one of the strongest in the world. The vegetation is unique and is dominated by
perennial plants that occur in mixed species clumps, interspersed with bare land which, in
the winter season, is covered by annual plants. The height and structure of perennial
plant species is relatively uniform. The area also has a high proportion of endemic
succulents. These factors make the region sensitive to disturbance, with the recovery of
disturbed areas taking extended periods of time.
Translocation
trials began in March 2001 with the selection of five locally common perennial plant
species. One species was a shallow rooted stem succulent with drought-deciduous succulent
leaves (Othonna cylindrica), another species was a drought-deciduous stem succulent
(Zygophyllum morgsana), two species were shallow-rooted evergreen leaf-succulents (Ruschia
versicolor and Lampranthus suavissimus), and a further species had below ground storage
organs (Asparagus spp.). It was assumed that the presence of storage organs would make
plants more adaptable to translocation. Once species had been selected, a new
rehabilitation area was identified and trials began. Two categories of plants were
collected: these were either from stockpiled topsoil (salvaged plants) or from undisturbed
vegetation ahead of the mine face (whole plants).
The entire
experiment was set out in June 2001. Six hundred plants of each species (300 salvaged and
300 whole plants of each species, totalling 3 000 plants) were collected and transplanted
by the rehabilitation labour team at Namakwa Sands. One of each of the five species was
planted together in multi-species clumps. All salvaged or all whole plants together,
creating salvaged-plant clumps or whole-plant clumps. Plant clumping is thought to benefit
plant growth and survival in this region of Namaqualand. Two treatments, each with two
treatment levels, were applied to all clumps and these related to the substrate that
clumps were planted onto, and whether irrigation was applied. Clumps were either planted
on tailings only or onto stockpiled topsoil spread over tailings. Irrigation was either
applied or not applied. If irrigation was applied, it was only applied in the winter
months, when it was required to augment the long-term mean monthly precipitation for the
mine site.
A total of 1
200 plants (240 plants per species, 120 salvaged and 120 whole) were randomly selected and
repeatedly measured for survival, growth and ground cover – at planting and then
again at three monthly intervals. These measurements were used to determine the success of
the different species origins, soil treatments and irrigation treatments on the species
used in the study. This would help to determine which species types were more adapted for
translocation.
Results
indicated that for all species, whole plants survived better than salvaged plants. After a
period of fifteen months, O. cylindrica had the greatest proportion of plants surviving
(approximately 75% of whole plants and 50% of salvaged plants), no matter what the soil
treatment had been; followed by L. suavissimus, R. versicolor and Z. morgsana in
proportional order; with Asparagus spp. showing the lowest survival. R. versicolor, L. suavissimus, Z. morgsana and Asparagus spp.
survived better on stockpiled topsoil spread over tailings, than on tailings alone.
Unfortunately
due to the isolated location of the mine and the resultant lack of fresh water available
for irrigation at the study site, irrigation could not be consistently applied during the
trials – and results relating to irrigation did not have a consistent effect across
either species or treatments. Nevertheless, irrigated stockpiled topsoil spread over
tailings showed an improvement in growth – however, to varying degrees for different
species.
Clump size,
used as a measure of surface area cover, was affected by plant origin. At planting,
salvaged-plant clumps were larger than whole-plant clumps. This difference in size was no
longer present by July 2002. When considered in conjunction with the fact that whole
plants tended to grow more than salvaged plants, it can be assumed that whole-plant clumps
grew more than salvaged-plant clumps, thereby creating a greater increase in proportional
cover compared to salvaged-plant clumps.
Whole plants
of O. cylindrica, the shallow rooted stem succulent with drought-deciduous succulent
leaves, as well as the shallow rooted evergreen leaf succulent shrubs L. suavissimus and
R. versicolor, appeared to be most suited for translocation to facilitate rehabilitation
areas at Namakwa Sands. These plant species and other locally common plant species with
similar characteristics could potentially be used for large-scale translocation on Namakwa
Sands sites – however, each species should be tested individually. Due to the harsh,
dry summer conditions, translocations should be confined to the early to mid-winter wet
season, and should be carried out in conjunction with other proven rehabilitation
techniques currently being implemented by Namakwa Sands, such as seeding with species
indigenous to the area.
None of the
species selected for translocation have a high grazing value and this may be thought of as
a disadvantage, considering that the end goal of rehabilitation is to re-introduce
small-stock grazing to the area. However, there is an advantage. If transplanting of
non-palatable species is combined with the seeding of palatable species (as is proposed),
a vegetation structure of both palatable and non-palatable species will be created, in
which non-palatable species will create an environment more conducive to seed germination
and survival of palatable species. If the vegetation were to consist entirely of palatable
species when small stock was introduced, the vegetation would soon be overgrazed, leading
to further environmental degradation through soil erosion and to increased rehabilitation
costs. However, by planting non-palatable species, when small stock are re-introduced,
there would be palatable and non-palatable species on the land. Non-palatable species
could provide sites for palatable species to germinate and grow without being grazed and
would play a role in stabilising soils in the event that overgrazing did occur.
This study
shows that with ingenuity and foresight, rehabilitation in arid areas is possible. Namakwa
Sands has made an effort to develop original ways to solve rehabilitation problems in arid
areas and by applying a variety of new and old rehabilitation techniques together, the
environment should benefit.
Kirsten
Mahood graduated with an MSc (Forestry) (Conservation Ecology) cum laude in April this
year.
-----
‘Self-regulatory’
environmental work
Kutama-Sinthumule
Prison, Makhado
Carol Knoll
spoke to Ally Burger Pintér, director of SRK’s environmental department, about an
unusual environmental impact assessment undertaken at Kutama-Sinthumule Prison on the
outskirts of Makhado (then Louis Trichart) in Limpopo Province, where the environmental
philosophy was embraced wholeheartedly. Public participation revealed an interesting
perspective on prisons and an educational programme designed to increase environmental
awareness amongst the staff was extended through to the prisoners.
The project
was initiated some five years ago, in line with government’s policy of establishing
public/private partnerships. The Department of Public Works was exploring this concept in
the area of infrastructural development and a pilot project was set up calling for the
involvement of the private sector in four new prison facilities: an awaiting trial prison
at Benoni; a youth facility in Barberton; and maximum security prisons in the Free State
and Northern Province (now Limpopo).
One of the
teams bidding on the tender to finance/design/construct/ operate and maintain the facility
was South African Custodial Services (SACS), jointly owned by the Black women’s
empowerment group, Kensani, and the international correctional services corporation,
Wackenhut Corrections Corporation. The latter had established facilities in the USA,
Australia and the UK. The environmental department at SRK joined the project consulting
team to do the environmental work that was required. SACS’s construction partner
comprised Concor Holdings, Group Five Construction, Makhosi Holdings and four local
empowerment parties – Shumisanani Building and Civil Construction, FHM Building
Construction, NKN Construction, and Mposa Sikhwai and Tshibisi Construction. The group was
referred to as CGM Louis Trichart Joint Venture.
At that time
(1998), there was no maximum security facility in the Northern Province, and prisoners who
were resident in that province had to be housed elsewhere in the country contrary to the
principle that they should be accommodated within visiting distance of their families. The
Departments of Public Works and Correctional Services in conjunction with Louis Trichart
municipality had already determined the site for the prison by the time SRK came on board.
The site was on the south-eastern periphery of the town and bordered on middle to low
income housing, a community comprising Hindus and Muslims, an area of small holdings and
across the N1 freeway, a light industrial area. Amongst this hotchpotch of land uses and
bordering on the prison property was an electrical substation and the municipal landfill
site.
There is no
requirement by law for an Environmental Impact Assessment (EIA) to be done for a prison
facility – it is not a listed activity, but the relocation of powerlines is a listed
activity under the EIA regulations and this had to be undertaken to accommodate the
prison. Another reason for the undertaking of an assessment was the requirements in
Schedule P which formed part of the contract between the concession contractors, SACS, and
their client the Depart¬ment of Correctional Services. Schedule P required that an EIA be
done and that this be backed up by an Environmental Management Plan (EMP) for the
construction phase of the prison and an Environmental Management System (EMS) for the
operational phase.
The decision
was made to apply for environmental authority for the prison under the National
Environmental Management Act (NEMA), although there was no requirement by law to do so.
The relevant authority was therefore the Minister of Correctional Services. According to
Burger Pintér, it was highly gratifying to see that there was no evidence of resentment
forthcoming from the concessionaire about these largely self-regulatory environmental
requirements put in place by the client – and that the whole process was followed
within the spirit of true environmental concern.
A scoping
exercise, including specialist studies, was undertaken by SRK and this ran concurrently
with SACS’s development of the design concept for the facility. The 75ha site was
fairly degraded biophysically, having been grazed, although not cultivated, in the past. A
wetland, the large part of which extended into the urban periphery and was therefore
destroyed, was evident on site and a decision was made to conserve the remaining portion
on the prison property. Because the site fell within a transitional zone ecologically (or
a narrow ecotonal band), the need for a specialist study in this area was recognised and
SRK appointed Pieter Winter and Dr Wynand Vlok of the University of the North to do the
study. No threatened species were found but the attractive Aloe greatheadii was in
evidence. The site was invaded by alien species, predominantly Lantana camara. There were
reports of Giant Bullfrog and African Rock Python having been seen on site but these were
never confirmed. The water management study was done by Ronel Breytenbach of SRK and
hydrological issues were found to be standard. Biophysically nothing of great value or
concern was found on the site.
The prison
was re-orientated on the site to leave room for future extensions and SACS agreed to take
responsibility for the conservation of the unused portion of the property. The design of
the prison took careful account of visual impact. Burger Pintér emphasised that SACS had
worked expressly within the spirit of the EIA requirements at design stage. “I was
continuously encouraged by the willingness to question for the sake of learning, so that
environmental principles could be applied to future contracts – and this was
noticeable with SACS and CGMLT. The vice president of Wackenhut flew in from Miami to
attend every public meeting and presentation on management measures, taking note of those
significant aspects that shape a project from an environmental perspective, with an
enquiring mind and to give his stamp of approval.”
Sociologically,
an interesting factor came to light during the public participation phase. The Hindu and
Muslim communities expressed a strong antipathy towards the idea of having a prison on
their doorstep – their objection was related to a conflict that the proximity of the
prison would have with their spiritual well-being. This was of more concern to them than
fear for their physical safety, even though the proposed facility was to contain worst
offenders. Concern for their safety was certainly voiced by the interested and affected
parties (IAPs) on the adjacent small-holdings – particularly by single women.
A
socio-economic assessment was done by Allison McCallum of SRK in which IAP concerns were
fully discussed and researched. Mitigation was offered in terms of Wackenhut’s good
track record at their facilities world-wide where the design of the prisons precluded
escapes, and in the form of contractual documentation between the Department of
Correctional Services and SACS.
The renowned
Prof Ben van der Waal of the Department of Biological Services at the University of Venda,
an immediate neighbour, was one of the most vociferous of the IAPs. One of the concerns
that he expressed was about the long term management of the remainder of the prison
property. The consortium agreed to optimise the value of the vacant land for wildlife and
to prevent its deterioration into waste land by on-going eradication of invader species
and regular patrols to monitor the state of the veld. Suggestions were made that a joint
initiative should be set up with the Albasini Conservancy to develop a management plan for
the area and that a natural history group should be formed from amongst the prisoners to,
amongst other aspects, track changes in species composition in the wetland. Van der Waal
appreciated the recommendation that only appropriate indigenous trees should be planted on
the site.
No serious
concern was expressed by those living in the housing which bordered directly onto the
proposed facility or by owners in the industrial area across the highway. A property
evaluation study was commissioned and this study was done by an independent specialist,
Graeme Hart, to address the fears of a number of IAPs, including Prof van der Waal’s,
about the possible plummeting of property values. Although the study predicted that it was
possible that properties closer to the prison could be negatively affected, management
recommendations included mediation and arbitration between the Department of Public Works
and landowners in the case of devaluation occurring. Qualitative property evaluation
exercises were also recommended. The IAPs remained dissatisfied with these recommendations
as the onus of proof was on them and there was no guarantee that they would not suffer
financial losses.
On the
southern boundary of the property, the Emmanuel Christian School was appeased when an
agreement was reached that the access road to the prison would be the same road as that
used for access to the school and would, therefore, be tarred. One of SRK’s concerns
was the poorly managed waste facility and the effect that this would have on the health of
the prisoners.
Burger
Pintér commented that when the environmental authority to proceed with the prison was
granted, the IAPs still had concerns but they could not fault the procedure that had been
followed. At this stage, SACS had been informed that their bid was successful.
One of
government’s objectives incorporated into its concept of public/private partnerships
was to ensure black economic empowerment in such projects, and SACS offered opportunities
to local people to be included in all aspects of the project. Stringent requirements for
black empowerment were met throughout the project. There was a contractual obligation that
50% of the workforce for the construction phase had to be sourced locally. CGMLT ensured
that each smaller district had proportionate job representation. Procurement was also done
on a black empowerment basis. SACS proposed that previously disadvantaged individuals from
the region should fill 80% of all operational phase positions within five years.
A series of
‘job fairs’ was organised. These were advertised events which the local people
were invited to attend to find out what jobs were available, to indicate their interest
and reveal their skills. Burger Pintér commented that when she visited the construction
site, she was interested to see the large proportion of female construction workers. She
said it was also satisfying to see, at a later stage, that two of the most outspoken of
the IAPs had taken jobs in the prison. All the socio-economic criteria that were set for
the project were met and the economy of the Louis Trichardt area was considerably
stimulated by the project.
The EMP was
done by Cally Henderson of SRK and presented to the IAPs. “Everything required by the
EMP was done by the construction contractors – and done without complaint. If we
complained that topsoil stockpiles were the wrong gradient, this was corrected
immediately. We asked that informal trading, on what was a large construction site with a
large workforce, be formalised and this was followed through. Rubbish bins were provided
for both hawkers and construction workers and the latter received training in
environmental matters. There was no deviation from the EMP without consulting ourselves,
as environmental consultants. We were phoned by the construction director. There was never
an adversarial relationship between the environmental consultants and the contractors,”
said Burger Pintér.
“A
complaints management system was set up at the start of the EMP phase and this was managed
by the internally appointed Environmental Control Officer. Concerned IAP enquiries were
always dealt with. One of the pumps in the sewerage system was fixed immediately after an
IAP complaint concerning the resultant odour was received, and the pastor of the
neighbouring school who had raised the concern was assured that the problem had been dealt
with and would not re-occur.”
Further
fulfilment of Schedule P included an external audit done by SRK during the construction
phase and the training of CGMLT site staff in EMP procedure. This, according to Burger
Pinter, was very successful both from a legal/contractual perspective and in a general
environmental context. “The staff needed to understand the specifics of the site in
relation to the EMP – they needed an understanding of why certain activities were
required of them. Understanding is paramount. They were trained to audit their own site,”
said Burger Pintér.
The process
of developing the EMS which was done by SRK was linked to the prison’s quality system
and this was applied and monitored by an internal Environmental/ Quality Manager.
Kutama-Sinthumule Prison is due to apply for ISO 14001 certification later this year.
Three sets of training materials developed by SRK indicate the responsibilities of staff
members in relation to the EMS and teach general environmental awareness.
“We
assumed that the training materials were for the staff who were to conduct general
environmental awareness training at operational stage. We were asked to develop a series
of posters (see illustrations) and these focussed on contextualising the prison within the
bigger ecosystem – and to provide a fair number of these sets. When we visited the
prison, we found that the intention all along had been also to educate the prisoners,
along with the staff, to create environmental awareness as part of their rehabilitation
process,” enthused Burger Pintér.
She said
that SACS’s “philosophy of respect” had impressed her greatly. “The
prisoners are being supported to become whole members of society, even though they are
long term. They are seen as people who have made mistakes and not as bad people, and they
roam freely within their allocated sections of the prison and determine their own
activities. I was also impressed with the calibre of the staff – previously
unemployed local people. They were very receptive to environmental concepts and they
showed a remarkable understanding of these, being able to relate them to local examples,”
concluded Burger Pintér. She said her enthusiasm for environmental assessment work had
been given a new lease of life at Kutama-Sinthumule Prison.
-----
Habitat creation to encourage wildlife
On
River Club’s exotic parkland course
River Club’s
course manager Derek Muggeridge spoke to Carol Knoll about the ongoing programme to
encourage an increased diversity of birdlife and to improve the aesthetics of the golf
course. The River Club course was built in the late sixties along the lines of a typical
“parkland course” with lakes, large exotic trees and a highly manicured
appearance. Muggeridge is involved in the subtle incorporation of more natural areas that
do not detract from the overall appearance of the parkland scene. The gradual removal of
invasive plant species is part of the programme.
The River
Club course borders on the Braamfontein Spruit in the suburb of River Club in Sandton. The
initial impression is one of a course planted entirely to exotics and kept in immaculate,
if somewhat sterile, condition – but a trip around the 18 holes reveals a different
story.
The move
towards incorporating indigenous plantings was started some five years back when Tyrone
Yates was the course manager, and there has been a bird register in the clubhouse for a
number of years in which bird sitings can be recorded. Muggeridge, who has been the course
manager for the past three years, said that support for the project which aims to increase
indigenous wildlife through habitat creation has been forthcoming from the members. The
changes are being made gradually with the indigenous plantings being kept as formal as
possible in areas that are highly visible, as it is a priority to retain the manicured
parkland feel of the course. Ease of maintenance is another priority and Muggeridge says
that they are striving for a balance between encouraging birdlife and keeping the course
manageable.
The basic,
environmentally sound principle of doing only curative and not broadcast preventative
spraying of pesticides is an important aspect of wildlife habitat creation. The Hadeda and
Sacred Ibis which are plentiful on the course act as a natural control curbing outbreaks
of army worm. Muggeridge is fully aware of the fact that the more prolific and varied the
birdlife is on his course, the fewer insect problems will be encountered. There are also
insectivorous bats on the course and Muggeridge plans to put up bat boxes in the near
future to encourage the growth of bat populations which will also serve to decrease
problem insects.
“We
hardly have any problems with insect damage. Mole crickets, however, have to be dealt with
by selective spraying. They come out at night and we only spray in patches where the
insects are in evidence. The Aphodius beetle is sometimes a cause for concern over
November/ December. The beetle dies after it has laid its eggs and we see the small dead
beetles on the greens. About two to three weeks after that we need to spray with a low
dosage insecticide because the larvae eat the roots of the bentgrass. We know the damage
is inevitable, after we see the dead insects, and in the heat of summer the grass will
simply not survive with its roots damaged,” commented Muggeridge. “If the course
is carefully monitored on an ongoing basis and the course manager has a reasonable
knowledge of the life cycles of various pests, there is no need to do anything other than
minimal curative spraying – and this management principle saves money, along with
protecting the environment.”
He also
commented that since the number of feral cats on the course had been brought under
control, there had been a subsequent increase in various bird species such as Crowned
Plovers. Blacksmith Plovers, he said, were always prolific as they liked the water on the
course. Their natural habitat is the short grassy verges of dams and vleis and they lay
their eggs close to the shoreline. Plover eggs which are usually laid on exposed sites are
protected from trampling at River Club by being demarcated with a dead branch.
Wetlands to encourage
birds
Careful marginal plantings of appropriate indigenous wetland species were done
along the banks of the large dam on the 18th fairway, when the dam was extended in early
2002. A small peninsula and islands in the dam have been extensively planted to indigenous
species interspersed with rocks, to serve as refuges for water-fowl. Muggeridge visited
Linda De Luca, a grower of indigenous plants, to find out which plants would be best
suited to the marginal plantings and would maintain a compact, neat appearance. He was
keen to try new species that had only recently become commercially available.
He felt that
some colour was necessary and this has been provided by two species of Crinum lilies
(Crinum campanulatum and C. bulbisper¬mum) suitable for waterside planting, the Crimson
Flag (Hesperantha coccinea), the (Red) Hot Poker (Kniphofia linearifolia) and Aloe
cooperi, a species with apricot coloured flowers which favours marshy areas. Arum Lilies
(Zantedeschia aethiopica) and the Otterbossie (Gomphostigma virgatum) which grows in rocky
streambeds in Gauteng were also planted, along with sedges – Juncus effusus and
Cyperus prolifer – and wetland grasses.
An area on
the far side of the dam has been left fairly free of vegetation for the feeding of duck
species with duck pellets and crushed mealies. Species that frequent the dam are
Yellowbilled Ducks, Shelduck, the African Black Duck, Moorhen, Dabchick and Redknobbed
Coot. Muggeridge said that he had observed the latter to be territorial as they had
originally chased away other water-fowl but now that feeding was happening and the other
species were more prolific and had taken up residency on the lake, there seemed to be only
one Redknobbed Coot pair remaining.
He explained
that Egyptian Geese were the only species not encouraged on the course because of the
damage they do when they are grazing on the greens. Although this has not been
scientifically proven, it is a common belief that their droppings often contain Poa annua
seed and this problem plant is spread to the greens in this way. The maintenance staff try
to stop the geese from breeding on the course.
Muggeridge
has often spotted Greenbacked and Purple Herons in the denser wetland plantings and the
larger heron species – the Grey and Blackbacked Herons are also in evidence on the
course. Cormorants are common and Pied Kingfishers are seen on the course, along with
periodic visits from Giant and Brown-hooded Kingfishers, which are sometimes spotted
perching on the wooden bridges. Muggeridge is aiming to attract more kingfishers by
providing more perching areas for them, such as dead trees and logs in the dams.
The Red
Bishop is the emblem of River Club and there are only three colonies left on River Club
property. Muggeridge has been taxed with maintaining and increasing the habitat of
reedbeds comprising largely Phragmites and some Typha (bulrushes) which provide nesting
sites for the Bishops, so that the existing colonies can be increased and new colonies
established.
The water
course/stormwater channel next to the 14th tee was becoming undermined, eroded and
cluttered with weeds. The area had been back-filled with rubble and old tree stumps in the
past and the latter had decomposed, creating voids. Muggeridge removed the old rubble and
back-filled the area with soil, creating a gentler slope and a wider grassed embankment
for stability and better attenuation of storm¬water, adjacent to the renovated water
course. An out-of-play area between the large dam on the 18th and the small dam on the
14th was planted with supplementary reeds and bulrushes to preserve habitat for Red
Bishops – and because it has a slightly unkempt appearance it was screened from the
course by means of tree plantings of Karree (Rhus lancea) and River Bushwillow (Combretum
erythrophyllum). These will also serve to screen the maintenance road.
Along the
9th fairway, the existing water course has been given a more natural appearance with small
weirs of rocks and wetland plantings, such as Juncus, Cyperus and Restio species. Silt
build-up behind the small weirs creates ideal habitat for waterfowl to wade and scratch
about in. Sacred Ibis, Hadedas and Black-smith Plovers are continually occupied in these
areas.
The dams and
water courses have been stocked with indigenous fish species – two species of Tilapia
and Yellow Fish donated by one of the club members. Exotic Bass and Barbel have been in
the dams for decades and yet the indigenous fish stocks which could serve as a food source
for the larger exotics are, according to Muggeridge, not becoming depleted. The Tilapia
are breeding quite prolifically. The idea is to gradually remove the exotic species in
favour of more desirable indigenous species. There are terra¬pins breeding in all the
dams and Muggeridge favours the creation of small sandy areas to encourage further
breeding – but again such areas will have to be carefully positioned so as not to
impinge on the manicured aesthetics of the course. Muggeridge concluded that working on
the course was a continuous balancing act “…but wherever we can we favour the
wildlife.”
Removing aquatic weeds and other invasive plants
Muggeridge is very aware of the invasive species on the course and he has instituted a
programme of gradual removal of such plants, whereas he is treating the removal of all
category 1 weeds as a priority. There was an infestation of Red Water Fern (Azolla
filiculoides) at River Club a few years back but this was brought under control by means
of a biological agent (see Jul/Aug WSSD issue of UGF, page 127). There has been no sign of
the weed at River Club for the past two years. The Water Hyacinth (Eichhornia crassipes),
however, is still in evidence in small pockets in between areas of reeds and the
maintenance staff have been removing it as it re-occurs. Muggeridge is planning to look at
one of the biological control agents to rid the course of this category 1 weed.
An original
planting theme in and adjacent to many water features at River Club included the well
known ornamental, rooted exotic water plant, the Pickerel Weed (Pontederia cordata), with
its attractive spike of blue flowers. This plant was declared an invader species (category
3) in the amended regulations 15 and 16 of the Conservation of Agricultural Resources Act,
in 2000 – meaning that if it had already been planted prior to the revision of the
regulations, there is no immediate need for its eradication but no new plants of the
species may be planted. Category 3 plants, however, may not occur within 30m of water,
whether this is a natural or man-made body of water. There are dense clumps of the
Pickerel weed on a number of dams and Muggeridge is gradually thinning out the plants in
winter and will be replacing these with indigenous plantings.
Pampas
Grass, a category 1 weed, is being dug out of wetland areas with a TLB excavator. Removal
of Syringas, Wattles and Mulberries on the course, and the gradual thinning out of some of
the more un¬kempt looking mature Eucalypt spe¬cies, along with continual removal of the
saplings, is also done efficiently with the stumps and roots being removed by the
excavator. This guards against regrowth. If there is regeneration of some of the invasive
species, Roundup is sprayed on the regrowth because it is environmentally friendly. New
plantings of indigenous trees, particularly Combretum species are being done on an ongoing
basis, and the invasive exotic trees such as the Privets will gradually be replaced by
these trees – no new Privets (Ligustrum lucidum), category 3 invaders, will be
planted.
Again,
Muggeridge pointed out that this removal of invasive species has to be a subtle process as
the golfers, particularly the older members, have a sentimental attachment to the old
trees. Some of the larger non-invasive exotic species such as the Swamp Cypress and Black
Oak, which are planting themes on the course, are still being planted because using trees
as hazards in the game of golf is an integral part of the design of the course at River
Club.
-----
Solar heat and energy demonstration
centre
Challenging
conventional power systems in buildings
The Solar
Heat and Energy Education Centre, newly established by a partnership between Solar Heat
Exchangers cc and Divwatt (Pty) Ltd in North Riding outside Johannesburg, presents
physical installations of various solar energy devices, all on one site. It demonstrates
how solar energy can be used to generate heat and electricity in buildings and for various
other applications, challenging conventional power systems.
Dylan Tudor
Jones of Solar Heat Exchangers (Solar Heat) says that the idea of the demonstration and
training centre arose from discussions leading up to and during the Johannesburg World
Summit on Sustainable Development. There is a great need to increase awareness of
renewable energies in South Africa, of their potential applications and environmental
benefits. The Department of Minerals & Energy (DME) is developing similar centres and
encourag¬ing other players in the energy sector to do so as well, although Tudor Jones
suggests that more needs to be done in schools and in the public domain to educate South
Africans about alternative energy sources and the environment. South Africa enjoys
particularly high levels of solar radiation but this valuable energy source is scarcely
being tapped. He says that in those countries, like Germany, where there is the highest
level of awareness and education regarding renewable energies and their environmental
benefits – as opposed to the detrimental impacts of conventional coal- and oil-fired
power stations – usage of renewables is much greater and the respective industries
are much better developed.
The new
energy centre brings together the solar water heating products of Solar Heat and the solar
power generation products of Divwatt to demonstrate their installation and applications
and to support training. The centre is open to existing and prospective clients, in
particular to architects, mechanical and wet services engineers and other professionals,
contractors and artisans interested in making use of solar energy. There are also plans in
place for training programmes – for plumbers on installation of solar water heaters,
for example, and electricians on installation of photovoltaic panels to generate
electricity.
Solar water heaters
Tudor Jones emphasises the importance of using closed circuit solar water
heaters. There are various products available to suit different markets and requirements.
“The open circuit systems that were used in the 1980s gave solar water heaters a bad
name because, in open circuit systems, the solar collectors are vulnerable to damage by
frost and prone to internal lime-scale build-up. This was why solar panels in the open
circuit systems would sometimes burst in winter and why there were circulation blockages,”
says Tudor Jones. In closed circuit systems, the heat transfer fluid used in the enclosed
heat exchanger incorporates an antifreeze component and a rust inhibitor. In addition, the
composition of the solar collectors has been improved to maximise solar heat absorption,
although this varies in different systems.
The solar
water heating systems on display at the energy centre combine imported collector panels
and locally manufactured geysers. As Tudor Jones says, “In all our installations
– from households, to health clubs, to hotels and lodges – we have to be able to
guarantee the kilowatt output of the collectors, which translates into a certain capacity
of hot water in a given temperature range over a fixed period of time. The collectors we
use have been tested independently to meet such guarantees, whereas standards and test
facilities in South Africa are lagging far behind those in place internationally”.
Solar technologies have advanced rapidly over the past decade and South African standards
and test methods have reportedly not kept up with these developments.
Another
obstacle that has often been raised against solar water heating (as well as electricity
generating) systems has been that they are aesthetically intrusive, often bulky, and in
the case of solar powered electricity, inadequate to support efficient and attractive
electrical and mechanical fittings. This prejudice has been specifically countered at the
energy centre where two different systems, one smaller and one larger, are installed
respectively in a thatch roof and a concrete tiled roof, demonstrating that solar panels
can be fitted flush with the roof line and need not protrude from it.
This is done
simply using a typical skylight flashing, about 75mm deep, into which the sealed solar
collectors are mounted. The geyser of the solar water heating system, depending on its
dimensions and on the configuration of the roof structure, can then be mounted in the roof
space. This too is demonstrated in the thatch roofed building at the energy centre where a
200l geyser is mounted internally, near the apex of the roof, screened from below by the
mounting boards yet accessible for maintenance.
Ideally, in
a solar water heating system, the geyser should be located above the solar panels, in
order to take advantage of the natural flow of hot circulating fluid upward into the
geyser and cooler fluid downward from the geyser into the heating panels. However, this
flow can be forced by incorporating a pump into the system if the geyser is of a size that
cannot be contained in the roof space. In larger household and commercial installations,
geysers are often located in basements or out of the way service areas.
The other
conventional requirement – that solar panels (whether for water heating or
electricity generating systems) should be pitched at the latitude of the location +10°,
in order that the contact of the sun’s rays to the panels be as close as possible to
perpendicular in winter when solar radiation levels are lower – has also been
overcome by technological improvements. Where this requirement used to necessitate a roof
pitch of around 37° in Johannesburg, for example, Tudor Jones says that collectors have
been so improved that the same results can be achieved even if the panels are not pitched
precisely according to this rule.
In terms of
aesthetics, solar panels can, for example, be arranged to create a feature in themselves;
they need not be roof mounted but can be separately erected on a terrace; and for
companies or organisations keen to declare their ‘green’ status or claim some
environmental kudos, they can be used boldly in any building. On average, on the highveld,
each square metre of collectors absorbs enough solar radiation to heat 100l of water.
Standard sized domestic water heating systems range from 200l to 450l and commercial water
heating systems range from 600l upward.
Smaller,
low-cost, household systems are also displayed at the energy centre. As awareness of the
environmental and cost benefits of using renewable energies grows in the South African
marketplace, so household demand for solar water heating systems is increasing. Minimal
maintenance costs and no expense on electricity make solar water heating systems
especially appropriate for low-income households and particularly those remote from the
power transmission grid. Tudor Jones says that although the company encountered some
problems – of non-payment, vandalism and theft – in its early experience in the
low-income housing market in the late 1980s, this sector remains important and can clearly
benefit from solar energy applications.
Another
application of water heated by the sun is seen in the installation of an underfloor
heating system at the energy centre. Instead of conventional systems which run electric
wires just beneath the floor surface, the solar underfloor heating system channels tubes
through the floor slab. When hot water is circulated through the tubes it heats the slab,
not only the surface of the floor, and because the heat is retained in a concrete floor
slab, the warmth in the room is longer lasting. Thus a more efficient underfloor heating
system is achieved, without the cost of electricity and without any detriment to the
environment.
The
temperature of the water circulating in the underfloor system is monitored by a control
thermostat which automatically maintains a constant heating level, within a couple of
degrees. The system can be designed to service prescribed areas, in isolation from others.
It does require an additional depth of 75mm in the floor slab to accommodate the tube
network and additional insulation and is therefore more suitable for installation in new
buildings than in retrofit projects.
Other
demonstration products installed at the energy centre include a solar system for heating
pool water and a solar hot-water outdoor shower.
Solar and hybrid power
generation systems
A single 40W photovoltaic (PV) panel is mounted on brackets on a north-facing
column, at an angle to optimise collection of solar energy. It is installed at eye-level
so that its components and functioning can be easily explained. This panel, 1m by 400mm
and just 15mm deep, together with the control unit which incorporates a built-in
regulator, a high-cycle lead-calcium battery and the required switches, produces
sufficient power to operate three or four lights, a small radio and a black and white
television. It is typical of the solar home systems that are being installed by the DME
and its concessionaires in the rural electrification programme. JP de Villiers of Divwatt
explains that a simple plug-in inverter can transform the DC power supply to AC, to feed a
colour television or a hi-fi system. The number of modular PV panels can readily be
increased to provide a greater solar power supply. At the energy centre the single 40W
module provides power for three 7W high efficiency fluorescent lamps.
A hybrid
system combining four roof-mounted PV panels (300W) and wind energy from a domestic-scale
turbine (400W) is used to power a DC fridge, two conventional ‘five-foot’ 75W
fluorescent lamps, high efficiency lighting, an 85W ceiling fan and plug points. According
to De Villiers, hybrid systems are cost efficient as they can amplify the power supply at
a lower cost than could be achieved using a single energy source. In this hybrid
installation, the wind and solar energy is channelled through a regulator to distribute
the load at manageable levels across a bank of six batteries.
The wind
turbine currently installed is imported from the USA, although a turbine designed and
manufactured in Zimbabwe is also being investigated. The PV panels used are manufactured
in The Netherlands and other components are sourced from Germany or manufactured locally.
De Villiers says that there has been some endeavour to design wind turbines in SA but the
costs of wind tunnel testing (at the Council for Scientific and Industrial Research) are
high and present an obstacle to local entrepreneurial development in this field.
Divwatt has
also designed a solar-powered street lamp, a prototype of which is installed at the energy
centre. The 10W module, with a lamp-head similar in size to those commonly used, contains
45 LEDs (tiny light emitting diodes, each with about a 5W light effect). It is a
lightweight, self-contained, pole mounted unit, designed to operate 12 hours a day, and is
suitable for outdoor and street lighting. Samples have been distributed to countries like
Angola and Zambia that are keen to make use of abundant solar energy.
Since 1993
Divwatt has produced solar-powered submersible water pumps, mainly for farming and other
rural applications where infrastructural distribution networks are not in place. About 70%
of the pumps produced are exported. The Solastar 3B solar-powered submersible pumps have
been acclaimed by independent authorities as the most efficient in the world. The pumps
can run dry, function at any angle and can be used in rivers, dams or wells. Made of
stainless steel they are virtually maintenance free. The delivery and lift of the
solar-powered pump is dependent on the size of the array and the type of PV panels used.
The system is capable of providing 1 350l an hour and can pump a lift of up to 200m. A
borehole pump powered by four PV panels is installed at the energy centre –
demonstrating just one more way in which solar energy can be put to use in place of
coal-powered electricity or, as is the case in many rural areas, to save women and
children the hours spent in collecting water.
Other
environment-friendly technologies on display at the energy centre include a solar cooker
and a composting toilet. Tudor Jones says that the centre runs virtually independently of
conventional municipal services. Other applications of renewable energies will be
introduced over time, as new technologies and products are developed. |
