Cape Water and Dams Report
(Stettynskloof Dam. Now full. Photo : DWS)
Dams – Latest levels: Winelands and Cape Town
Report nr. 113 (updated 16th July 2018) on the main dams serving
Cape Town City and nearby Boland/Overberg towns
Mainly continued run-off and some limited additional rain helped combined dam levels to increase by a further 15.1 M.cuM (1.7% of capacity). Total stored water rose from 53% of capacity to 54.7%.
In the same week of 2017 the dam levels lifted by 8.8 M.cuM (0.6%) to 26.1% of capacity.
How long will the water last?
Within another few weeks I expect that we should have enough water stored to enable us to reach winter 2019 without any undue hardship or risk of rationing. Hopefully we will soon have around 60% of capacity (530-540 M.cuM) on hand.
As I wrote last week, once 60% of capacity is passed, it would not be irresponsible of DWS to consider permitting the municipalities to sell more water and to thereby lower the water tariffs to some extent, reducing the financial pressure on hard-pressed consumers. We now understand that DWS will in September consider proposals to relax restrictions.
Although some feel that we should not ease restrictions – and we certainly will not want to squander the water that we do have stored – it would make no sense to allow water to spill over the dams and run down-river to the sea while still subjecting the populace to high restriction levels.
(Here is our model predicting the amount of water likely to be stored in the dams.)
I have made a mid-month adjustment increasing the anticipated month’s net inflow from 55 M.cuM up to 72 M.cuM. If this eventuates it will mean that we would end July with some 502 M.cuM of water stored in the main dams.
Putting it into context!
There are two important perspectives to now consider:
1) Counting the cost of the drought.
One hears every day how difficult businesses in the Cape have found the economy to be under the recent severe water restrictions. This newly released chart by Quantec (below) indicates the extent to which the different sectors have in fact been hit by the water shortage.
Unsurprisingly, agriculture shows massive negative growth during 1st quarter 2018. The cost of this implosion is estimated to total in excess of R2 billion and even if rainfall patterns completely normalise, the impact in terms of lost production capacity is likely to be felt for several years to come.
With all the concern about hardship and inconvenience of water restrictions, the hospitality trade – which financial firm PWC calculates contributes R40 billion to the Western Cape economy and employs around 300 000 people – has also suffered substantially. According to a Wesgro survey, in January and February this year, bookings for hotels surveyed were between 10% and 15% worse when compared to the same period in 2017. These hotels indicated that there had also been a drop in bookings for the period from April to September.
For these and other industries, it is important that the availability of water be improved to permit economic activity to return to normal levels and for visitors to be attracted back to the Cape.
The raw cost of this drought to businesses and individuals in SW Cape has been massive.
2) If the panic is over – what next?
It is now reasonable to assume that we have survived the recent water shortage. Dams are recharging, the risk of rationing has fallen away and the authorities are likely to relax restrictions at some point as the urgency of the situation calms, particularly to permit the residents of the SW Cape to return to a more generous and less muscle-cracking use of water.
So what then is the next priority after survival.
Well, in a word, its ‘resilience’; to move steadily towards a balanced set of extra water production and supply methods that will ensure optimum levels of future potable water supplies, with the overall flow of water from all sources comfortably matching the growing demand, even in times of drought.
In pursuit of ‘resilience’ one starting premise is that climate change is a reality. Predictions for the SW Cape are that the effects thereof will be negative – less annual rainfall against a background of higher average temperatures and greater evaporation of surface water, all coupled to escalating water demand of a growing population point to significant future water supply challenges.
Dr Kevin Winter, of UCT, recently encapsulated the issues facing a city like Cape Town.
“A water resilient city should be capable of reducing risk by diversifying water sources to include supplies from groundwater, storm water, reused water, treated effluent and desalination. Resilient, water sensitive cities also integrate the whole urban water cycle into its water resource management system. This means, for example, being smarter about capturing rainfall across the city, in storing storm water underground, and in reusing treated effluent for a variety of purposes not necessarily for drinking purposes” according to Winter.
“Cities are the new catchments. There should be no reason to hesitate on implementing these actions. They won’t only climate proof the city, they’ll also make them healthier and more sustainable places to live.”
As the the water supply mix then changes from a monolithic dammed surface water supply system to a combination of local and bulk water supply sources, cities must take the lead.
In Winter’s judgement: “National government can’t be expected to lead cities in dealing with water scarcity and drought.” “Local governments are in a better position to take decisive action and act at a local scale where they can engage citizens, communities and businesses in averting the water crisis. National governments are slow to intervene, and when they do their actions are often not at the right scale or timely enough.”
But to be effective, “cities need more autonomy to act decisively, although proactive, inter-governmental support and cooperation is both helpful and necessary“, advises Winter.
Dr. Winter also stresses:
– “Measuring and monitoring is essential to understand water demand and flows”. This must be supported by “robust analytical and reporting systems.”
– Accurate messaging is critical: “what citizens really want to know is what actions are being taken to alleviate the crisis and relieve the risk.” But accurate information alone is not enough; the authorities must also “contain the level of misinformation shared in the public domain and media“.
– “Public trust is key to encouraging water saving and helping to establish confidence in managing the crisis. Trust is strengthened by honest, credible messaging when progress towards averting the crisis is demonstrated and understood, and when ordinary citizens, communities and businesses are engaged in making a meaningful contribution. Trust gains momentum when citizen voices are heard and when politicians and officials respond accordingly.”
Winter concludes: “If cities [like Cape Town] are going to become more resilient and responsive to climate change then a search for new water supplies will be necessary. Innovative approaches need to be explored because we might not yet know what these [new forms of governance] should look like. The future is uncertain, but there is a lot that can be done right now and we need to learn some hard lessons.”
What about Cape Town’s augmentation progress toward ‘resilience’?
According to the CoCT report, the contribution of augmentation has now risen to 39 ML/day.
This means that production of extra fresh water has risen over the past 10 weeks from 26 ML/d, an increase of 50% since mid-May 2018. It is likely that within a few more months, 10% of all potable water used in Cape Town will be coming from sources other than the dams – a great step in the right direction.
The downward pattern in water usage in the Metro has continued with water drawn from the dams dropping to a new low of 455 ML/d, just slightly above the target of 450 ML/d set by CoCT and DWS, while water used from all sources sank to 494 ML/d.
(Graph tracking overall use and production of extra water through the augmentation efforts)
See our report on the status of Cape Town City’s augmentation efforts here.
How well are we actually doing?
Here is the CoCT graph that shows the combined level of water stored relative to the danger zones.
My calculations indicate that SW Cape will move into safer territory once the dams reach a combined level of 60% of capacity, i.e. around 540 M.cuM of water stored.
Will the weather help?
Rainfall this past week was patchy; Voelvlei benefited most while the combined Steenbras sytsem actually dropped slightly.
Theewaterskloof Dam may appear to be rising steadily but run-off into this dam is being supplemented currently by transfers from Berg River Dam pumped at a rate of 3.5 cuM/second. Diversions from Wolwekloof and Banhoek are also diverting towards TWK. The main aim is to avoid/minimise spilling from Berg River Dam by the end of winter.
However, at this stage, combined rainfall remains below average for month July.
What rain ought we to now expect?
1) We received general rains as expected between 12th and 14th July. However the S. Atlantic High pressure system remained present and deflected more of the rain south of the country than had been originally hoped.
This high pressure cell has ridged around under the country and will deflect successive systems away over the sea this week.
2) Between 23rd and 27th July the High Pressure is forecast to move away and two coincidentally arriving low pressure fronts may bring light rain at first becoming heavier also in the catchments on 26th and 27th July; yielding perhaps as much as 40 mm in all.
3) Some weather instability is predicted to bring general light rains of 5-10 mm around 5-7th August. Occasional light rain is expected from time to time but no large unstable systems are predicted for the SW Cape during the coming 4 to 8 weeks
4) ENSO remains in neutral range at the moment but it is still expected that a warm El Nino will emerge during August.
What are the authorities doing?
There have been no significant developments on the water front this past week. DWS’ attention seems to be currently focused on Port Elizabeth where dams levels have worryingly declined below 20% of capacity.
Watch me answer the often asked question: “why do you write this report?“
Read the full City Cape Town release about Water By-law amendments here.
Read here about Cape Town’s reduced water and sanitation tariff increases.
Combined levels of the six main reservoirs serving the Cape Town/Overberg/Boland area rose from 53.0% to 54.7% of capacity.
Plan ahead for possible water outages; here are points that could help you.
Read our Indoors Water Savings Ideas here.
Read our Outdoors Water Savings Ideas here
Read about a D-i-Y household rainwater harvesting and tank system here
Click here to see Winelands Weather forecast of possible near-term rain.
Report instances of piping failures and incorrect use to municipalities.
In Cape Town the contact details of the 24-hour Technical Operation Centre are: Email: waterTOC@capetown.gov.za Telephone: 0860103089 (choose option2: water-related faults) or SMS: 31373 (max 160 characters).
Tom Brown. Retired international businessman with a background in Finance and IT; and now a fruit farmer, with a passion for the weather and climate.
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