Nicky Schmidt, chairperson Parkscape
Use ground water sparingly does not mean put in new/second borehole
Tony Rebelo’s response in the article (“Tighter water restrictions on the cards,” Bulletin February 2) is at one level amusing, and at another, concerning. With potable water in our dams down to approximately 29 percent, and underground water supplies under extraordinary pressure from borehole and well-point users, Dr Rebelo’s actions are disturbing at multiple levels.
As Bulletin readers may be aware, Dr Rebelo, a resident of Bergvliet, is a “fynbos specialist” with a doctoral degree from the Percy Fitzpatrick Institute of Ornithology at UCT.
Not only is he intent on taking over all of lower Tokai for the attempted regeneration/recreation of a Cape Sand Fynbos biome – and this in a vastly changed environment, and despite concerns about fire and crime right on the urban edge – he also has a fynbos garden at his home.
Cape Sand Fynbos, as we should be aware, has evolved to suit our Western Cape/greater Cape Town geology and climate – low nutrient soil conditions, winter rainfalls and long dry summers.
It’s a climate that is also prone to periodic droughts. Whether fynbos will survive prolonged droughts and global climate change is unclear. However, if the slopes of upper Tokai are anything to go by, where Port Jackson, black wattle and eucalyptus are flourishing and outgrowing fynbos, then it may seem not.
Professor Eugene Moll (botanist and ecologist), who taught Dr Rebelo many years ago, recently told
CapeTalk that he feels that all ground water extraction should be stopped, and that one should not presume that the winter rains will come.
This rather begs the question of Dr Rebelo’s actions in his own garden. Defying recommendations by the City to use ground water sparingly, Dr Rebelo, having let his well point run dry as early as November 2016, has, at the considerable sum of R57 000, not only put in a borehole to water his climate-adapted fynbos, but then gone down to an additional level of 55m.
Given Bergvliet is probably only 6m above sea level one hopes Dr Rebelo hasn’t tapped into sea water. As he is doing on lower Tokai, where he is planting and scattering seed, so it would seem that even in his own garden, Dr Rebelo is intent on intervening in nature and playing God.
Here Professor Moll’s point becomes highly pertinent. If winter rains don’t
arrive, and people follow Dr Rebelo’s lead, where will Dr Rebelo, his borehole, his fynbos and the rest of us be then?
As an aside, I too have a fynbos garden, half of which has been watered for the last few years and half of which was left to fend for
Having stopped watering my garden with the onset of Level 3 water restrictions, the half that was used to summer watering, is struggling, the section that was allowed to fend for itself, has adapted to water scarcity and is doing surprisingly well. Therein should lie a lesson for a certain Bergvliet gardener, though it seems that some special hypocrisy and double standards are at work in Dr Rebelo’s garden.
Dr Tony Rebelo responds: What a vitriolic letter. I will confine myself to issues and not character assassination. I do need to point out though that three of Eugene Moll’s ex students are involved in the Tokai Fynbos restoration: seems he did something right.
Your writer obviously did not attend my talk to the Bergvliet-Meadowridge Ratepayers’ Association on October 19 on “Waterwise gardening and the drought”. Please allow me to highlight a few points from my talk, as there is still much debate about what constitutes responsible borehole water use.
The Bulletin’s region covers two different geologies: granite and sand. Those with granite gardens can grow anything they like, with sumptuous gardens, and those on the deep acid sands have to struggle to achieve the same.
It is not surprising that the most affluent suburbs are on the granites. Historically, the Cape Flats were impassable with vleis and wetlands in winter and dry loose sand in summer.
The suburbs expanded into the Cape Flats as technology allowed these areas to be drained with canals, and flattened. Still, the Cape Flats is a huge underground aquifer that forms seasonal wetlands in winter, and draws down deeply in summer.
As water demand for gardening has increased over the years, homeowners with well-points have seen their summer water supply run dry as others have put in much deeper boreholes.
The current drought has exacerbated the situation. The city should monitor aquifer use, but if the situation does become dire and seawater invades the aquifer, residents nearer the sea will undoubtedly alert officials and action can easily be taken.
The Cape Flats Aquifer has a recharge rate of 53 million cubic meters per annum, and the potential to meet most of the city’s garden irrigation demand. Still, it is not infinite, and if not used responsibly could be overutilised.
Gardeners should therefore plan to minimise their garden’s water use by:
* Plant local fynbos rather than exotic species. * Plant small: small shrubs need far less water than tall shrubs and trees;
* Avoid water miners: plants such as proteas, pines, wattles and gums, which extract deep water (using the same aquifer as our boreholes) and grow during the dry season when other plants are dormant. * Keep your lawns small. Allow your grass lawn to die in the summer (the Vaalies have dead lawns in winter). Plant more hardy, indigenous grass.
* Do not water your beds more than twice a week. Water deep rather than frequently. Fynbos beds need watering when establishing, but after two/three years need not be watered.
* Use borehole and grey water for your gardens, not potable water. You can use all shower, basin, bath, and sink water on any garden, and washing machine water on most non-fynbos gardens.
* Water only before 9 am and after 6pm. Use drips rather than sprays wherever possible.
* Use ecofriendly detergents to do your dishes and washing. Use economy and eco-friendly cycles on your washing and dishwashing machines.
* Join hack groups and remove water-wasting alien wattles, pines and gums from our mountains. Keeping our mountains natural will save us having to build more huge dams to store water. The Cape Fold Belt sandstone aquifer is our next huge water source for Cape Town: don’t allow aliens to use it up. Most of our Cape Flats aquifer water comes from Constantiaberg and Table Mountain.
We need to be aware that borehole water is not a magical source, and that its overuse will result in the drying out of our nature reserves, wetlands and rivers. These systems also need this water, we humans cannot just take it all.
The winter rains will arrive soon. The question is how many years will it take to fully recharge our Cape Flats Aquifer if we overuse it? How many more years will this drought cycle persist? Please use all water sparingly: you may need it next year!