GROUND ZERO

We need to talk about the wa­ter cri­sis

Popular Mechanics (South Africa) - - CONTENTS -

There are a few things you need to know about the wa­ter cri­sis in Cape Town but first a lit­tle his­tory. The city’s orig­i­nal dam, Wood­head Dam on Ta­ble Moun­tain, was com­pleted in 1897 and aug­mented by the Hely-hutchin­son Dam in 1904. This 954 me­gal­itre (954 000 000 litres) bulk stor­age was enough to ser­vice the city and sur­rounds un­til the Steen­bras Dam came on­line in 1921 in the moun­tains above Gor­don’s Bay, along with its 64 km­long 750 mm cast iron pipe­line to feed the Mother’s ever-grow­ing de­mands. Wa­ter was orig­i­nally stored in the Molteno reser­voir in Oran­jezicht but in­creased sup­ply forced the con­struc­tion of ad­di­tional pip­ing and stor­age at the New­lands Reser­voir. This pro­ject was so wildly suc­cess­ful and ex­pen­sive that the in­de­pen­dent mu­nic­i­pal­i­ties of Cape Town, Clare­mont, Green Point, Sea Point, Kalk Bay, Mait­land, Mow­bray, Ron­de­bosch and Wood­stock banded to­gether as the Greater Cape Town Mu­nic­i­pal­ity to col­lec­tively con­tain this beastly un­der­tak­ing. Wyn­berg and Con­stan­tia at this point were fed by the Vic­to­ria, Alexan­dra and De Vil­liers dams since 1896 but soon joined in to ben­e­fit from the sur­plus.

In 1977, the Steen­bras Up­per Dam (the bit you see from the N2 when you drive up the Sir Lowry’s Pass) was com­pleted. The first pumped stor­age scheme in Africa dou­bled the dam’s over­all ca­pac­ity and is linked to the Rock­view Dam to ben­e­fit from the Eskom and De­part­ment of Wa­ter and San­i­ta­tion-owned Palmiet Pump Stor­age Scheme when needed.

Wem­mer­shoek Dam and its clay wall was the se­cond dam to be built out­side of Ta­ble Moun­tain area and was com­pleted in 1957. This pro­ject is sig­nif­i­cant be­cause it is the largest sin­gle stor­age fa­cil­ity owned by the city (dou­ble the ca­pac­ity of Steen­bras Lower) and its dam wall com­bi­na­tion of clay and rock em­bank­ment was, at the time, a lit­tle more than half the cost of a con­crete re­tainer. Wa­ter from this dam is also of a very high qual­ity and re­quires lit­tle treat­ment.

Voëlvlei Dam was built by DWS and com­pleted in 1971. The dam is fed by canal di­ver­sion of the Klein Berg, Leeu and Twenty-four rivers from the Porter­ville and Tul­bagh moun­tains. While the dam was built by na­tional gov­ern­ment, treat­ment and pip­ing in­fra­struc­ture was con­structed by the COCT. Simon’s Town is pri­mar­ily fed by the Klein­plaats and Lewis Gay dams but was con­nected to the City of Cape Town wa­ter sys­tem in 1997.

That brings us to the jewel in the Cape Town wa­ter sup­ply crown. Thee­wa­ter­skloof Dam is the sev­enth largest in South Africa (480 250 Ml, big­ger than all 13 other Cape Town dams com­bined and is in­ter­con­nected to the city and the Wem­mer­shoek and Berg River dams by 30 km of tun­nels run­ning through the Fran­schhoek, Groot Drak­en­stein and Stel­len­bosch moun­tains. Wa­ter is fed to the Klein­plaas Balanc­ing Dam in the Jonker­shoek val­ley and then into the main sup­ply.

Of Cape Town’s 14 dams, the three largest – Thee­wa­ter­skloof, Voëlvlei and Berg River – are all owned by the na­tional gov­ern­ment. This is im­por­tant be­cause the pro­vin­cial nar­ra­tive shifted quickly to ques­tion­ing the State in the face of the wors­en­ing cri­sis.

As the city con­tin­ues to grow and the sub­se­quent de­mand for fresh wa­ter also in­creases there are other wa­ter sources needed but no suit­able land is avail­able for a new dam.

The cur­rent op­tion be­ing tabled is a di­ver­sion of win­ter wa­ter from the Berg River to the Voëlvlei Dam (Berg River-voëlvlei Aug­men­ta­tion Scheme, or BRVAS) and trans­fer of wa­ter from the Breede River to the Berg River. With the BRVAS con­struc­tion costs es­ti­mated at R277 mil­lion to add 23 mil­lion cubes of wa­ter per an­num to the Voëlvlei stor­age it seems like the per­fect so­lu­tion. There’s just one prob­lem: there hasn’t been suf­fi­cient rain in the cru­cial catch­ment ar­eas and the cur­rent trend is sharply down­ward.

Ac­cord­ing to 2011 cen­sus data, the City of Cape Town pro­vides wa­ter and san­i­ta­tion services to 3,74 mil­lion peo­ple. Within this net­work there are nearly 650 000 prop­er­ties and ap­prox­i­mately 156 000 in­for­mal house­holds. Those 650 000 houses con­sume around 55 per cent of the drink­ing wa­ter, a 2,1 per cent de­crease since 2014/15. Much­ma­ligned in­for­mal set­tle­ments, how­ever, ac­counted for a mere 3,6 per cent of the to­tal wa­ter us­age in the 2016/17 pe­riod. How­ever, the data doesn’t re­ally mat­ter be­cause it’s all es­ti­mates.

It’s been the big­gest crit­i­cism of the City of Cape Town’s ap­proach to deal­ing with the drought. The ini­tial knee-jerk re­ac­tion was to paint the cit­i­zenry as the big­gest cul­prit in an ag­gres­sive drive to save wa­ter through self-polic­ing and pub­lic sham­ing. With av­er­age do­mes­tic use cal­cu­lated be­tween 200 and 600 litres per day – or be­tween 72 and 216 kl per an­num – the pro­vi­sioned wa­ter is more than suf­fi­cient when the weather op­er­ates as sched­uled. But out­dated cen­sus data (re­ported con­sump­tion num­bers are cal­cu­lated over the two-year pe­riod from 2014/15 to 2016/17) and shal­low con­sump­tion data (an over­whelm­ing per­cent­age of me­ter read­ings are es­ti­mates be­cause of un­der­staffing and a lot of wa­ter is wasted to re­store ser­vice af­ter leaks are re­paired) make many of the mea­sures seem un­trust­wor­thy.

In short, the City of Cape Town doesn’t have re­li­able data to sub­stan­ti­ate many of the con­sump­tion claims and by not ac­tively polic­ing the in­stal­la­tion of wa­ter fea­tures since start­ing wa­ter re­stric­tions in 2015, or by not em­ploy­ing enough op­er­a­tions tech­ni­cians to deal with a creak­ing retic­u­la­tion sys­tem, the city ex­ac­er­bated the prob­lem. We are told that the im­me­di­ate so­lu­tion is de­sali­na­tion be­cause the rains aren’t ex­pected to re­fill the dams and a 95 per cent re­liance on that sys­tem isn’t sus­tain­able with the long-term ef­fects of cli­mate change.

Is­rael, a coun­try of an es­ti­mated 8,8 mil­lion peo­ple is pre­sented as the leader in de­sali­na­tion tech­nol­ogy be­cause it went from drought to a state of wa­ter sur­plus. In 2008, the Sea of Galilee, Is­rael’s pri­mary wa­ter source, was weeks away from the “black line” the point of no re­turn for salt­wa­ter in­fil­tra­tion and bore­holes were be­ing dug up to 500 me­tres deep to chase the re­treat­ing wa­ter ta­ble. Day Zero was loom­ing.

The Is­raeli gov­ern­ment started in­stalling low-flow toi­lets and show­er­heads in 2007 and, through in­no­va­tive wa­ter treat­ment, reached 86 per cent waste-wa­ter re­cap­ture to be used for ir­ri­ga­tion. Cur­rently, de­sali­na­tion ac­counts for only 55 per cent of potable wa­ter and fu­ture plans for brine – sea­wa­ter de­sali­na­tion’s big­gest headache be­cause of the dam­age it can do to ocean ecol­ogy – dis­posal is a canal run­ning across neigh­bour­ing Jor­dan to re­plen­ish the Dead Sea.

TI­TLE: Re­fill

DE­SCRIP­TION: Of our three toi­lets, there is one prob­lem­atic 7,5-litre flusher that doesn’t op­er­ate cor­rectly with­out a com­pletely full cis­tern. Water­loo was sup­posed to be the answer to this prob­lem but poor design im­pairs the sys­tem’s ef­fec­tive­ness.

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