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The Cape Water Crisis: solutions and obstacles

13 Nov 2017

The current drought in the Western Cape has bitten deeply. The relentless pressure of El Nino, coupled with a growing perennial pattern towards dryness in the area, has placed the City of Cape Town in crisis mode. With dams sitting at only 28%, there have been numerous efforts to curb water usage, and investigations into ways to produce water from sources other than the surrounding dams.

South Africa’s history of drought

Drought is a common occurrence in South Africa. While this 2015 – 2017 drought may be the worst in recorded history, South Africa like many other areas is at the mercy of the El Nino Southern Oscillation (ENSO) cycle which has been particularly virulent in the Cape this time around.

El Niño is caused by the lowering of an atmospheric pressure system over the southern Pacific, which causes the westerly winds to drop and the ocean temperatures to rise. This has an effect on weather patterns around the globe, and not always in the same places. The last bad El Nino was in 1997/1998 and did not greatly affect South Africa. Eight out of the last ten worst droughts in the past 100 years have taken place during ENSO.

Since the recording of rainfall began in 1904, 2015 saw the lowest rainfall ever recorded. Figures show that South Africa received only an average of 403 mm (66% of the annual average). The lowest rainfall previously recorded was in 1945 when South Africa received 437 mm (72%).

However, the driest period experienced in South Africa may still prove to be the years between 1930 – 1933 because of the continuous length of the period of low rainfall. Droughts are measured by the unbroken timespan of low rainfall figures. While 2015 might be the lowest rainfall measured, the early 1930’s period may still be the driest on record. The average rainfall for those years was 519 mm annually (85%).

Types of drought

Apart from meteorological drought measured by lack of rainfall, there are three types of drought:

Agricultural: This is defined by a lack of soil water to support the growth of crops, caused by too little rainfall, whether it meets the requirement of a meteorological drought or not.

Hydrological: This is caused by the low availability of surface water, such as low water levels in dams, rivers, lakes and other reservoirs. It can be caused by a meteorological drought or high water use, for instance.

Socioeconomic: This occurs when human activity is affected by any type of drought. This may be in the form of lack of water supply, grazing land or food.

City of Cape Town’s response to the challenge of drought

Currently, as we head out of 2017, Cape Town is experiencing the worst drought in recorded history, and in May, the Western Cape was declared a disaster area. The City of Cape Town has stated that the supply of municipal water will run out around March 2018 – and should next winter of 2018 prove to be another dry season – we will need every extra plan we can put in place now to survive the year ahead. As a result of this concern, several steps are being put in place:

  • Aggressive reduction of consumption has been enforced via extreme water restrictions on general consumers. This will include water rationing carried out via pressure reduction during peak hours in preselected suburbs.
  • Alternative water resources such as desalination, groundwater and water reclamation are being actively pursued to ensure that existing surface water can sustain us through to winter 2018.
  • Small-scale, temporary, containerised desalination plants (with a combined yield of approximately 15 million litres per day) are to be established in Hout Bay, Granger Bay and Dido Valley.
  • While desalination plants are a viable option, a drawback is the time it takes to implement these facilities. Initially, seventeen sites were under consideration for generating water, but after environmental considerations had been factored in, this number was reduced to ten when researching desalination or groundwater suitability. Sites must be situated close to the reticulation system for the water supply to enter the supply system and this creates complexity and challenges.
  • The aim, or rather the hope, is that between December 2017 and March/April in 2018, approximately 150 and 250 million litres will be in production, increasing to some 300 million litres by May 2018. If the plan keeps to target, and on track, this expectation will include land and sea-based desalination, as well as water reclamation and groundwater abstraction projects.  
  • However, these desalination plants and other plans, stand to cost the City of Cape Town billions of rand. It is not entirely clear yet where and when funding sources will become available, although  many channels will be followed, including reprioritisation of existing water projects and curtailing expenditure elsewhere in the administration. But as a consequence, Cape Town residents may expect to shoulder stiff tariff increases during the 2018/2019 financial year.

Drip irrigation – water in the desert

For farmers, or those with gardening concerns, understanding the beauty of drip irrigation is vital. When Simcha Blass made the startling discovery in 1938 that plants did not need copious water falling on them from above, but merely a small amount delivered directly and regularly to the roots, he revolutionised farming in dry areas; no more so than in his home country of Israel where drip irrigation practices, honed and perfected over decades, are now the brilliant solution to the challenges of food production in that extremely water-scarce country.

There are various systems designed to suit both environmental conditions and plant needs, either surface or subsurface options with cleverly innovated nozzles that resist clogging. The advantages of drip irrigation are numerous, and include: saving on water and costs, preventing run-off and wastage, alleviating weed buildup, and allowing for specific nutriments to be included in a perfect balance of water and nourishment to each individual plant. It is possible to continue farming in times of drought.

Netafim’s promise  

While Netafim is able to assist farmers – from small holdings to large commercial operations, we can also save your garden provided you have a borehole or rain water tanks. Our systems can be attached to either of these water sources to supply small, exact amounts of water to the roots of plants, trees and lawns. Our inventions and ingenious systems have been developed to challenge the ravages of drought wherever it occurs. Whether you want to simply save water and costs, or survive through the rigors of the unpredictable ENSO, or bring the desert to bloom, we have the technology to counter climate change – right here, and right now.   

Find out more at: www.netafim.co.za


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