How city will cope with the drought
This is an extract from a speech by City of Cape Town mayor at a media briefing yesterday to provide an update on the current drought situation and share the city’s medium-to-long-term water plans
I HAVE called this media briefing today to provide the media with the update on the current drought crisis as well as outline our ongoing water demand management and supply plans.
The media, as conveyers of our message to the public, have a very important role to play during this time of crisis and we are going to provide an overview of the current situation, what we have done, what we are doing now and over the medium- and long-term, and what our emergency measures and contingency options could be, in the event that we need them.
As of February 27, dam levels dropped to 33% which is 1.5% down from a week ago.
With the last 10% of a dam’s water mostly not being useable, dam levels are effectively at 23%.
Consumption is at 837 million litres of collective usage a day, which is above the revised water consumption target of 700 million litres a day.
Consumption is therefore still way off the required mark and we need everyone to immediately implement even greater water conservation measures.
At the current draw-down rate, and with dam levels at an effective 23%, we could be looking at approximately 121 days of useable water left.
We are in a very serious crisis and we know there are still some customers who are acting as if our resources are not under strain.
Just last week, we were still issuing fines to people washing their cars with potable water, people using a sprinkler to water their gardens outside of the designated times, and people using drinking water to wash down hard surfaces.
I also want to use this opportunity to thank the many residents, businesses, industrial and government consumers who are making every effort to save water.
Water restrictions are a normal measure to implement in a drought, but at the same time we continue to plan proactively as part of our longterm plans.
The fact is that during normal periods, people take water for granted. But because we have a demand management programme such as reducing pressure and implementing restrictions, we have progressively driven demand down.
This is internationally accepted best practice as the reaction to a drought is not to build a new scheme.
Building new schemes is part of our plans and we could look at accelerating our medium- to long-term programme to bring the plans forward.
We would never be able to build a water scheme big enough to give us 400 million litres of water a day in a short space of time, so saving water is the quickest and most practical way of ensuring supply.
During a time of drought, drastically reducing water usage is in accordance with the operating rules of our supply system and is a requirement of the regulator and custodian of our water resources, the National Department of Water and Sanitation.
The reason our dam levels have been depleted so much is not because of an increase in demand or high levels of water lost through leaks and bursts.
It is because we have received significantly low rainfall for two years in a row.
Cape Town lies in a waterscarce region and climate change projections have seen lower-than-average rainfall in the past two winter seasons.
The rainfall recorded at our Table Mountain and Steenbras gauge sites during 2015 and 2016 was among the lowest on our record of about 100 years.
The implementation of restrictions is a normal and required practice in water supply management, and it is introduced during drought events as a means to immediately trim the demand to the available supply.
As a result of the water restrictions, Capetonians have brought summer consumption down by 27%, from more than 1.1 billion litres at the same time last year, to about 800 million litres this year.
This is a remarkable achievement and, had we not implemented water restrictions, we would be in an even greater crisis.
What we have done to mitigate the crisis
We have proactively implemented water restrictions before being required to do so, in January 2016.
We have been successfully implementing water conservation and demand management since 2000, through pressure management, leak detection and repair, and education and awareness programmes. During the current drought, we are optimising and fast-tracking these programmes where possible.
We have reduced water losses for the overall systems from around 25% in 2009 to below 15%.
We are fast-tracking some of our medium- and longer-term infrastructure programmes – all planning remains firmly on track in terms of the 2016 update of the Western Cape Water Supply System Reconciliation Strategy.
During the current drought and restrictions, we are now using these pressure management zones to further reduce and optimise pressures in the water network.
To date, this has resulted in additional savings of around 20 million litres a day and further pressure reduction will be done to increase the saving effect.
As an additional measure, the city has also begun lowering supply pressure from our largest bulk water reservoir at Faure to decrease pressures across large areas of Cape Town. This is being done slowly to ensure that supplies remain stable.
In our own operations, the city has implemented drastic water-saving measures. This includes not watering vegetation in our parks, issuing strict directives for the use of only non-potable water in cases where vegetation must be watered for essential purposes, and even shutting off the water supplied to fountains, irrespective of whether non-potable water is being used.
In addition, washing of the exterior of our buses, which was previously undertaken on a daily basis, was limited to once every two weeks. In many of our buildings, we have retrofitted our toilets with dualflush water-wise toilets. We are currently expanding our existing pressure reduction programme to achieve more water savings.
In terms of the city’s response to reports of pipe bursts and leaks, we do our level best to respond to complaints as soon as possible. Our teams prioritise the most severe faults first where the highest water losses will occur.
The city manages a vast water infrastructure network of approximately 11 000km of water pipe lines, 650 000 water connections, and 9 500km of sewer lines.
Where we can improve efficiencies in our own operations, we are making every effort to do so.
For example, we are going to provide additional resources for our front-line teams who respond to the smaller water faults such as isolated pipe bursts or leaks.
An additional budget of R22.4 million will be allocated to the city’s Water and Sanitation Management Department in the new financial year for an additional 24 teams to do first-line response, for nine additional dispatchers, and for three additional shift supervisors at the dispatch centre to serve areas in the city. The filling of these positions will commence in March using savings realised in the current year. What we are going to do: medium- to long-term resource and infrastructure plans
Infrastructure investment is based on long-term projections of demand. Our system is designed and modelled with the operating rules that, during drought years, we introduce the necessary levels of restriction to limit the demand in order to ensure sustainable supply – as per international best practice.
We therefore promptly responded to lower rainfall as early as 2015 by implementing Level 2 water restrictions effective from January 2016, which pre-empted a directive from the National Department of Water and Sanitation, published in the Government Gazette in September 2016, to do so.
New supply schemes
Long-term planning and implementation of water supply schemes is done in collaboration with the National Department of Water and Sanitation, and according to projected population/demand growth and rainfall projections. Based on these projections, a new supply scheme is required in 2021.
The Voëlvlei Augmentation Scheme. This would involve building a scheme to pump excess winter water from the Berg River into Voëlvlei Dam. This will cost R274m in capital costs to implement and R500 000 in operating costs. The yield of the scheme will be approximately 60 million litres a day and will be implemented by the National Department of Water and Sanitation.
Extraction from the Table Mountain Group Aquifer is being considered. The yield from this will be approximately 50-100 million litres per day. The scheme will be implemented in phases. Costing is currently being done.
Water reuse is also being considered. This will yield an average of 220 million litres per day. The cost includes R4.5bn capital expenditure and R500 000 operating expenditure.
Desalination is also being considered. This will yield an average of 450 million litres a day. The cost is R15bn capital expenditure to R1.2bn in operating expenditure.
The Table Mountain Group Aquifer
The feasibility study and plan for future implementation of a groundwater scheme using water from the Table Mountain Group Aquifer (TMGA) is being timed according to growth in water demand in the region, and water availability from the Western Cape Water Supply Scheme.
As such, full-scale implementation of a first phase of a groundwater scheme is planned.
However, with the current drought and the risks of changing water availability and climate in the mediumterm, the city is considering certain emergency schemes should there be another winter of below-average rainfall, and will also be considering bringing forward its water resource programme to address the risks.
It must be clarified that the TMGA scheme was never cancelled, as has been claimed. This is essentially on track for its implementation date according to the medium- to long-term water resource plan for the Western Cape Water Supply System.
Its implementation date was moved on from when it was originally envisaged, mainly owing to the significant success of the city’s aggressive implementation of its Water Conservation and Demand Management Plan, which resulted in significant deferment of the need for additional resources for the entire WCWSS.
We remain committed to the exploration into groundwater extraction.
The original project plan envisaged that the pilot phase would take the form of a smallscale water supply scheme that would feed treated groundwater into one of our dams.
The exploratory phase also identified another promising site for possible extraction, near Theewaterskloof Dam, of which we were previously unaware. The pilot project plan therefore also had to be adjusted to include the further exploration and pump-testing of this site.
The pilot phase, including extended exploration, commenced in 2015, with the design of the further exploration and pump-testing boreholes.
Further exploratory work and drilling for pump-testing is scheduled to commence later this year, along with continuing ecological and environmental monitoring. Desalination In terms of desalination costs, one study shows that for the city to build the first phase of a 450 million-litre-aday desalination plant, it could cost approximately R8bn for a yield of 55 million cubic metres per year. This cost is only related to building the plant and excludes the operating costs. Such costs would have to be recovered by the tariff and would have significant implications for the cost of water to residents.
We have plans to implement a pilot for a desalination plant to be done in conjunction with Eskom, which has been very supportive in the planning process.
Springs
The city has been aware of these springs of the Table Mountain range and has been utilising some of them in various forms for some time. The city is applying to the national government to use these springs more extensively and, if this application to further harness these springs is successful, they will be used for irrigation and to otherwise offset the demand on our potable water resources.
The city’s studies show that the yield from these springs is not enough to offset the current drought.
For example, the Oranjezicht spring source flows out at approximately 2.77 million litres every 24 hours. However, this varies according to the season and long-term rainfall patterns.
As such, even if the water from these springs had been licensed, it would not have made a significant difference.
Any suggestion that these springs could be the answer to the water crisis is untrue and the city continues to strongly encourage adherence to the current water restrictions, as this is critical to ensuring that our water supplies are protected.
Certain high-yielding springs can be used for irrigation of sports fields, parks and other larger-scale gardens. Currently the known use in the CBD is the irrigation at the Green Point Park and surrounding area, cleaning of streets, and irrigation in sections of the Company’s Garden.
Further measures to manage demand – what we are going to do In terms of water-shedding or intermittent supply, this can lead to air entering pipe systems, which may cause burst water mains and associated water wastage and water quality deterioration owing to sediment being stirred up during pipe refilling.
Intermittent supply has also not been proven to result in real net savings of water. The city therefore prefers, as far as possible, to reduce demand through water restrictions. The city chose to rather pre-emptively implement water restrictions to try to avoid getting to the point where intermittent supply was unavoidable.
However, our contingency planning is looking at the option of intermittent supply, should the storage in our dams reach critical levels and should intermittent supply become unavoidable.
As we proceed through summer and autumn, if we see that the rate of fall of the dams is not responding and slowing down as required, then we will progressively intensify restriction measures and reduce pressures to lower consumption.
We are also looking at implementing emergency schemes using groundwater from the TMGA and reusing water from treated wastewater effluent as well as pumping water from the Cape Flats Aquifer for drinking water use. These could be prioritised for implementation in the event that we have another winter of below-average rainfall.
In the medium-term, we will be bringing forward the water resource implementation programme to address the risks of reduced water availability and increased climate variability.
If we should get to between 15-20% storage levels in the dams, we will increase the water restrictions measures and decrease water pressures in the network.
At between 10-15% storage levels in the dams, we will implement intermittent supply in some areas, with stringent restriction measures.
At below 10% storage levels in the dams, we will be providing a “lifeline” water supply, which would involve minimal supply pressures, intermittent supply, and very stringent restriction measures.
Further restrictions will entail no irrigation and no topping up of swimming pools.
The city would also consider intensifying Level 3 restrictions for the remainder of summer and autumn this year.
This would mainly entail stopping all garden watering and all exemptions would be revoked, and would need to be re-applied for.
Emergency and contingency measures:
I will be writing to the Western Cape Minister of Environmental Affairs, Anton Bredell, to declare a proactive disaster so that we can get the assistance to help us manage the water crisis more effectively.
The city can declare a disaster in terms of the Disaster Risk Management Act and the national government would fund and implement emergency water supply schemes.
Our work on the mediumto long-term plans is continuing but as part of our emergency measures, we are bringing some of this work forward depending on climate variability.