Following on Nolo recent blog and Zanele’s comment on “living in a fish pond”, Etienne did a bit of research on climate change and flooding. Here is what he found.
In a recent article in the UK Observer, a journalist quoted a question asked by Stephen Emmott in his recent book called Ten Billion. “What would happen if humanity discovered tomorrow that there was a asteriod on a collision course? An event like that could result in a large chunk of life on earth being eradicated”. Like in the movie Deep Impact, the world’s leaders would gather top engineers, scientists and business leaders, to try and stop the disaster.
This may sound like a scene in a movie but humanity finds itself facing a similar global catastrophe and we have been the cause of this pending catastrophe. Many of us have heard of global warming and climate change, we’ve watched “The Inconvenient Truth” and in that moment promised ourselves to start looking after our planet. However, according to the most comprehensive report ever conducted into climate change, there is a 95 per cent certainty that people’s greenhouse gas emissions are heating the world. This is the main finding of the UN Intergovernmental Panel on Climate Change’s (IPCC) fifth assessment report, known as AR5. Yes, human activities are responsible for climate change.
In the Western Cape of South Africa, evidence that the climate is changing and that climate change is affecting the planning and day to day operations of the local government and communities, is now becoming overwhelming. Minister Rejoice Mabudafhasi said “Over the past years, South Africa has experienced an increase in severe weather such as flooding, lightning, thunderstorms, tornadoes and in some areas, excessive and unbearable heat, which caused damage to property and infrastructure as well as several incidences of loss of life”.
According to Midgeley et al.2005, the Western Cape will experience:
• altered rainfall patterns both in distribution and intensity and consequent flooding
• rising mean temperatures
• sea level rise, both permanent inundation and discrete sea level (storm surge) events
• more frequent temperature extremes
• heat waves
• drought periods
• intensification of wind, predominately south-easterly
In the Western Cape, rainfall is generally expected over the winter months from June-August. In 2013 the Western Cape experienced heavy rains and snowfall well into late September 2013 – showing that rainfall patterns are changing. Certain areas in the Western Cape received the highest rainfall in 19 years in late August, early September 2013. Dams in the Western Cape were on average 102% full, the highest levels in 34years.The extensive rainfall led to flooding in many areas – which is in line with the possible increase in the frequency and intensity of flooding events due to climate change, suggested by Midgeley et al. (2005).
The impact of flooding in the Western Cape is of great concern to local government. The Western Cape experiences four main types of flooding:
• Flash floods – sudden flooding in small river basins
• River floods – where prolonged heavy rain in an upper catchment increases water levels in river channels leading to flood waves, such as the recent flooding of the Berg River in Paarl
• Rising floods or pooling – this is the accumulation of water in an area that leads to general flooding, this mainly occurs in wetlands and areas with a high water table. This type of flooding occurs most of the time in the Western Cape – badly affecting
informal settlements built on wetlands and floodplains
• Storm surges and Coastal floods – this type of flooding happens when water is pushed to abnormally high levels against the coastline. It is caused by a combination of extreme low pressure and strong winds pushing water into a narrowing feature, such as a bay or estuary.
The City of Cape Town in the Western Cape suffers from relatively heavy rainfall during the wet months of winter. While much of City has adequate and fully functional stormwater infrastructure, most of the informal settlements located on the low lying Cape Flats, lack sufficient stormwater infrastructure and proper maintenance of stormwater infrastructure. This, together with their poor location on unsuitable land such as wetlands and floodplains, as
well as poor housing quality, all lead to the increased risk of flooding. The consequences of flooding in informal settlements, include the compromise of public health and safety, destruction of personal property and adverse livelihood impacts.
Of the roughly 120 000 households in the 226 informal settlements in Cape Town, each year on average 70 informal settlements, 7500 structures, 30 000 people are affected by flooding and more than 2480 people are displaced. After a day of heavy rainfall sewer systems and electricity services will on average respond to 1556 calls and tend to 839 blocked drains in informal settlements. Disaster Risk Management assist on average 2566 people daily and provide 22 000 meals and 13 000 blankets to people in informal settlements. The services provided to people in informal settlements as well the destruction to property in the Cape Town costs the City millions of rands each year.
The City of Cape Town municipality has a budget of R34million rand for flooding disaster relief and spent up to R16million rand on disaster relief following the August/September floods in 2013. However, when flooding disaster relief exceeds the budget the City declares the affected areas disaster areas. Disaster areas are declared when a local municipality is unable to cope with their own resources or more than one municipality is affected. The financial and social implications of floods that have exceeded the allocated budget have been well documented for the Western Cape for the last 10 years.
Dates Area affected Social Impacts Direct Damage Costs(million rand)
March 2003 Cape Winelands, Eden and Overberg District 2000 people evacuated, Three deaths in Knysna and Hermanus 214.4
August 2004 City of Cape Town 20 000 informal residents flood affected 6.5
December 2004 Cape Winelands, Eden and Overberg District 3700 homes and 40 business premises damaged 54.9
April 2005 Cape Agulhas Municipality Residents of Kleinbegin flood affected 8.9
August 2006 Cape Winelands, Eden, Overberg and Central Karoo District 1200 people displaced 510.5
June 2007 West Coast and Cape Winelands District People from low cost housing, informal settlements and farms evacuated 128.5
November 2007 Cape winelands, Eden, Overberg and Central Karoo District Over 300 people from low cost housing, informal settlements and farms evacuated 957.6
July 2008 West Coast District 71.7
August 2008 City of Cape Town Coastal property damage and extensive flooding in areas with inadequate drainage 4.9
November 2008 Overberg, Cape Winelands and Eden District 996.0