News

What does it take to secure a resilient water supply?

by Robert Keessen  |  7th November 2019

Our communities expect the government to deliver reliable and resilient water supplies.

The east coast of Australia is in the grip of a drought, the second in the first two decades of this century. Many areas of western NSW are already running out of water, and urban areas on the eastern seaboard are not far behind. Sydney’s water storage levels have taken less than 3 years to drop to 50% capacity.

Storage volumes in Sydney’s Reservoirs
Source: adapted from Water NSW

Sydney’s Water storage reached a low of 32% capacity during the Millennium drought. Most of the drawdown occurred in the worst 6 years of that drought and it took about 4 years for storages to refill after that.

Following the Millenium drought, the Federal Government Productivity Commission was asked to “…identify ways of improving resource allocation to achieve long term water security”. In 2011 the commission concluded that:

  • Governments have responded to drought with prolonged and severe water restrictions and investments in desalination capacity.
  • The costs of water restrictions and inefficient supply augmentation have been billions of dollars per year nationally.

The Productivity Commission recommended a reform package to provide consumers with greater reliability of supply.

Drought returned to the eastern seaboard in late 2017. This time:

  • The weather has been drier than the Millennium drought, with storages drawing down more rapidly.
  • A desalination plant built in response to the Millennium drought was turned on in January 2019, and reached full capacity in June 2019, to supply 250ML/day, to provide an additional 15% to Sydney’s normal demand.
  • Planning has started for the second stage of the desalination plant which would double the total desalination capacity.
  • Stage 1 water restrictions were re-introduced in July 2019.

We are faced with a similar, but worse situation to what we were in a decade ago.

How bad could it get?

The city of Cape Town had a critical water shortage in 2018 and came within 90 days of running out of water. Residents could only use 50 litres a day, about a quarter of what the average per person in Sydney uses today. This is severe, considering a short shower may take 15 litres, and a toilet flush is between 4 litres and 10 litres on average.

Will Sydney also need severe restrictions to survive the drought?

This is not easy to predict, but if the drought continues at its current severity storage volume is likely to fall below 25% capacity some time in 2022. And if this drought lasts as long as the last one, it won’t break until late 2023. This means that there is a real possibility that severe water restrictions will be needed as early as 2022.

If this happens our communities will be asking how we got into this situation and what needs to be done to prevent it from happening again.

A paradigm shift is needed.

Water systems design from the 1900’s were based around centralised systems, that harvest runoff and transport it to the city to be used once. However, there are a range of other water sources available which are non-rainfall dependent including:

  • Desalination, which is potentially an unlimited supply but is expensive and energy intensive.
  • Recycled wastewater costs less to produce than desalination, but potable re-use does not yet have public acceptance and is more likely to be acceptable in the long term. There is considerable opportunity to supply recycled water through a secondary pipe distribution system to new developments.
  • Stormwater recycling is also possible and would be suitable for developments where there is space to accommodate relatively large storages.
  • Groundwater from aquifers also provide an opportunity where they have the adequate capacity (and have not been contaminated) and could be part of the mix of solutions.

Better results will be achieved with dynamic and adaptive systems, with:

1. Customer engagement that allows them to:

  • Express their willingness to pay for more secure water supply and introduce pricing policy (such as tiered pricing) that enable customers to pay.
  • To tell them how they can lower their water bills by having their own local (place-based or household based) systems.

2. Regulatory form to:

  • Recognise the value on non-rainfall dependant water supply sources, particularly where supplies are scarce. The cost of new water may vary from less than $1.00/kL up to $5.00/kL, which is very significant when water is being sold at around $2.00 to $2.50.
  • Encourage integrated solutions by removing ‘ring-fenced’ pricing for water, wastewater and recycled water products.
  • Encourages private sector participation, including access to cross subsidies available to public sector utilities.

3. Smarter strategy, planning, and design of our systems, by:

  • Diversifying water sources to include non-rainfall dependent sources.
  • Identifying a range of diverse solutions tailored to specific areas that use new technologies.
  • Integration of local systems with existing centralised infrastructure.
  • Adaptive management that has options to increase supply ready and known decision points for when to enact them to avoid restrictions.
  • Integrated water cycle planning to obtain the benefits of recycling water in local communities rather than the exclusive use of a centralised single use system.

These topics will be explored in further detail in subsequent articles…. coming soon.

Robert Keessen is a Project Manager at Warren Smith & Partners, a consultancy that has delivered solutions for the water business since 1981. Robert heads up a practice called Water Smart Solutions, that looks to provide strategic and planning advice that is fully grounded in the practicality of delivery. For more details see: https://www.warrensmith.com.au/civil/water-smart-solutions/