Dr. Andrew Venter Blog

Flooding our future

April 16, 2012

According to Swiss Re, 2011 saw the highest natural catastrophe and man-made disaster based economic losses in history. Over US$ 116 billion in insured losses and over US$ 370 billion in economic losses. This “record” was triggered by unprecedented events, including earthquakes in Japan, New Zealand and Turkey, and massive floods in Australia and Thailand. I believe that the scale of these losses reflects directly on the combined impact of growing population pressure and poor spatial planning. Essentially, we have played Russian roulette with the placement of urban centres in known earthquake and flooding zones, and the density of people living in these areas is increasing all the time as our planet’s burgeoning population migrates to these centres in search of a “better” life.

The “top ten” fresh water flood losses in history paint a particularly scary picture. 7 of the 10 events happened in the last decade and 3 in the last 18 months! These include the December 2010 floods in Queensland Australia, the January 2011 floods in Victoria Australia and the July to November floods in Thailand. The insured loss of the two Australian floods was over US$ 4 billion and the Thailand flood was over US$ 12 billion. Time will tell whether this pattern is a fluke or a long term trend which is going to get worse. Climate Change projections suggest it is a pattern which is going to get worse.

Over the December 2010 to January 2011 period, flooding in South Africa affected 33 Municipalities, highlighting that South Africa is flood prone and that we have limited ability to deal with disasters of this nature. KwaZulu-Natal is particularly vulnerable in this regard as we are not only likely to see an increase in rainfall, but more regular cyclone action and increased intensity of rainfall events. I don’t believe that we’re ready for an increase in flooding events. Furthermore, I’m really not convinced that we’ve factored in the projected impacts of Climate Change into flood management measures. A simple example is the River Horse Valley development in Durban, situated on the banks of the uMhlangane River. This development has been a primary development node for the City over the past decade, effectively covering the river’s floodplain with a mix of light industrial complexes. The uMhlangane has a history of spectacular floods, including the 1996 flood which saw the river rise 2 metres. Theoretically, the flood protection measures associated with this development take floods of this nature into account, having been designed to protect the estate from a 1:100 year flood. The question is whether a 1:100 year flood projection is still relevant. With the increased rainfall and storm projections, a 1:100 year flood may well now be a 1:75 or 1:50 year flood!

If the uMhlangane River “overwhelms” the flood protection mechanisms, we’ll not only lose a massive economic hub, but we’ll also be left with a downstream river and off shore pollution nightmare. Surely, this is not the sort of risk we should be taking? The River Horse Valley development is fait accompli. At the time that the decision was taken to proceed with this development, Climate Change was a far more distant threat and environmentalists were simply annoying. Today, Climate Change is an emerging reality and environmentalists are indulged with “slightly” more respect. Unfortunately, I’m not convinced that this is enough to stop another River Horse Valley development. Let me know what you think: http://andrewventer.wordpress.com/