Wag­ing war on leaks won’t win Mother City’s wa­ter bat­tle

Mail & Guardian - - Business -

Min­is­ter of Wa­ter Af­fairs and San­i­ta­tion Nomvula Mokonyane met Cape Town mayor Pa­tri­cia de Lille and other of­fi­cials early last month and urged the city to fix leaks as a way to fur­ther pre­vent un­nec­es­sary losses.

But ex­perts say, at this stage, it’s no sil­ver bul­let to solve the city’s prob­lems.

Kobus van Zyl, a hy­draulic en­gi­neer in the Univer­sity of Cape Town’s depart­ment of civil en­gi­neer­ing, said, in fact, the city has the best wa­ter in­fra­struc­ture in the coun­try when it comes to leaks.

“You can’t get leak­age to be zero in any sys­tem. There will al­ways be some and you won’t find them all, be­cause some will be hid­den from view un­der­ground.”

The in­fra­struc­ture leak­age in­dex rates how leaky a sys­tem is. Cape Town, at 2.2, is the best in the coun­try, said Van Zyl. Jo­han­nes­burg is at about eight.

“If the city spent all the money in the world on leak­age re­duc­tion, they could get it down to maybe 8% in­stead of 16%. That is part of the so­lu­tion, to con­tinue to re­duce leak­age. But if you can spend the same money and get peo­ple to use wa­ter more ef­fi­ciently, that is a bet- ter so­lu­tion,” he said.

“For the same money, you could re­place all shower heads with wa­ter­ef­fi­cient shower heads. As a wa­ter man­ager, there are var­i­ous things you can do. It is about how to spend the avail­able money in the best way to get where you want to be.”

In a wa­ter cri­sis, you re­duce con­sump­tion and look for short-term gains in sup­ply, which is what the city is try­ing to do, he said.

Re­duc­ing pres­sure in the pipes re­duces stress and helps to con­tain leak­age. But in­ter­mit­tent sup­ply, dubbed wa­ter shed­ding, as a gen­eral rule is very bad for the wa­ter sys­tem. When wa­ter is shut off, pollutants can en­ter ex­ter­nally into cracked pipes. The air in the sys­tem also in­creases the in­ci­dence of burst pipes by 300%, Van Zyl said.

“Cape Town has been pretty good in re­sist­ing in­sti­tut­ing in­ter­mit­tent sup­ply. What they are do­ing now is prob­a­bly the right thing to do. This is re­ally an emer­gency short-term mea­sure … It’s not a good thing, but not as bad as the al­ter­na­tive.”

Ul­ti­mately, Cape Town faces a large tech­ni­cal fail­ure brought on by a fail­ure to plan for the worst, he said.

Van Zyl said plan­ning wa­ter in­fra­struc­ture to meet pro­jected wa­ter de­mand is crit­i­cal and the cus­to­dian of that, the depart­ment of wa­ter af­fairs and san­i­ta­tion, should be the driver of long-term plan­ning and think­ing about wa­ter re­sources.

The depart­ment has said it will fast-track the im­ple­men­ta­tion of the Berg River-Voëlvlei aug­men­ta­tion scheme, which it hopes to com­plete by the win­ter of 2019. There are also plans to start work on the rais­ing of the Clan­william Dam wall.

The min­is­ter has de­scribed the wa­ter short­age as “the new nor­mal”. —

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