Rotary water talk

The Rotary Club of Somerset West, which meets on Monday evenings, is fortunate to count among its members Dr Jo Barnes, Emeritus senior lecturer at the University of Stellenbosch, who holds degrees in Mathematics and Epidemiology, and got her Doctorate in Community Health.

She works part-time in the Community Health Division at the Medical Faculty at Tygerberg, and describes herself as the unwanted voice of conscience to all public institutions dealing with water.

She recently gave a talk to the club entitled “An overview of the present water situation in the Cape Metropolitan area and the Western Province.”

Demand for water is outstripping the supply, and 98% of our water resources are already allocated. However, we have increasing urbanisation and a corresponding demand for safe water. Every year thousands of new families come to the Cape Town area and, although not all stay, this puts a huge burden on water, sanitation, schools, housing and other services, she said.

While water losses are not only caused by domestic water users in their gardens and with their pools, they are the main, and easy, target of the severe water restrictions issued by Cape Town municipal services.

“The Department of Water and Sanitation estimates that R7 billion worth of water is lost across South Africa due to waste and leakage. Water lost in the system of pipes due to leaks and burst water mains represent water that has already been provided to municipalities and then lost,” she pointed out, adding “this is where water conservation should begin”.

Municipal water reticulation systems are in poor shape and maintenance has been underfunded and seriously neglected, and sewage plants have fallen into disrepair, polluting our rivers with their poorly treated effluent.

Rainfall in the last five years has been markedly decreasing, year on year, but this may have been due to the El Nino effect, and that cycle will hopefully wane during this year, she said.

That, however, does not help the Theewaterskloof Dam, which is rather shallow and loses much of its water due to evaporation. What is left has become turbid due to wind and wave action and when that happens, the purification costs are greatly increased.

What can be done? More dams are not necessarily the answer. Rainfall in South Africa is notoriously variable and may not fall in the catchment area of many of those dams we already have. In fact, 60% of the total annual runoff arises in only 20% of the surface area of the country, namely the eastern parts. The western parts are much more arid. In many areas the underlying soil is rocky so water is not stored in great quantities, while abstracting groundwater from it is difficult.

Desalination is very expensive and requires a large amount of electricity, thus large scale desalinisation could lead to power shortages. The waste brine has to be disposed of, and as this is so saline when it gets pumped out to sea, the sea floor around the outlet pipes is severely degraded.

Mossel Bay does have a desalinisation plant, but the drought was broken before the plant was commissioned. In order to prevent the plant from deteriorating it is operated on a small scale but the connections to the main water carrying system were never put in place, so the purified water is, unbelievably, returned to the ocean, she said.

In most municipalities storm water comes under the Roads department. In general their main task is to remove any excess storm water off the roads as rapidly as possible, before traffic is affected. Such storm water is usually channelled into drainage systems with rapid discharge to the nearest river. In many parts of the City this water is hugely contaminated by sewage and other pollutants so that it poses a serious health risk. Such water would need to be purified before it would be fit for human consumption.

The cost of treating such contaminated water is likely to be even greater than desalination. However, we could do more ourselves to save water, for example by catching and reusing runoff water from our roofs.

The City of Cape Town intends targeting 20,000 “High Volume” users and is planning to issue them with stiff fines. Contrary to popular myth, township users are very economical with water, because they have to fetch and carry every drop they use, she said.

Grey water suitable for reuse comes from showers, washing machines, and sink basins, but not from toilets. Water from kitchen sinks as well as dishwashers should also be excluded as such water contains food particles, blood, fats and oils that give rise to high counts of harmful bacteria. Such water can also contain toothpaste, medicines, female hormones, deodorants, pesticides, dyes and cosmetics – in fact any product that the inhabitants wash down the drain.

Plants can react in an adverse manner to soaps, fats and oils and do not thrive when irrigated with such water. Grey water should be used only in where there is minimal human contact and never on edible crops as that can pose a health hazard.

Dr Barnes’ talk was a wakeup call for us all to do more: but unless the municipalities and the government come to the party, individual efforts are, if you will excuse the pun, a drop in the ocean. Domestic water users cannot salvage the present situation on their own, and local authorities need to get their own house in order.

Mervyn Cole does PR for the Rotary Club of Somerset West.

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