From routine to radical: water planning in the era of mega-drought

How should drought management adapt for unprecedented mega-droughts? What plans are needed beyond routine restrictions? How can decision-makers be convinced to act proactively despite low perceived risks?  

These were some of the questions posed at the recent AWA Water Efficiency Specialist Network Member Circle.

Exploring the application of risk-based thinking to drought management and water conservation, participants heard from HARC Principal Water Resources Engineer and Economist Russell Beatty and Jacobs Strategic Planning Engineer Jim Fear.

Beatty began by discussing why a no-regrets approach to drought management is not just preferential, but essential.

“A lot of my work has involved looking at what happens during extreme supply failures – whether that’s a dam failure or the failure of a rainfall-fed supply. I want to map out these scenarios and highlight what needs to change in our thinking,” he said.

“Australia relies heavily on rainfall-fed water supplies. Our systems were designed to withstand droughts we’ve experienced over the past 100 to 150 years. But now, we’re talking about mega-droughts – events that could last decades, and these are fundamentally different.”

Beatty said routine droughts follow predictable patterns: we impose water restrictions gradually, which gives storage levels time to recover and, once the rain returns, restrictions are lifted.

“But with extreme or mega-droughts, even when restrictions are applied, supply continues to decline. This happened in Sydney’s most recent drought – we saw levels fall far beyond expectations and much faster than anticipated,” he said.

“Here’s the issue: We might think we’re ready because we have plans in place, but what if the drought is worse than anything we’ve experienced before?”

Preparing for the worst

To illustrate the planning dynamic current in play, Beatty turned to a strike analogy: “In 1987, a boxer named Tyrell Biggs said he had a plan to beat Mike Tyson. Tyson’s response? ‘Everyone has a plan until they get hit’”.

“The reality is, our plans might look good on paper, but they are often tested and fail when unexpected events hit us. We need to be prepared for that punch,” he said.

In a routine drought, we are well-prepared with trigger levels and timing for introducing water restrictions, Beatty said: "We have prohibited and permissible water uses clearly defined. We implement demand management and education programs”.

“But for extreme droughts, our plans are often vague. ‘We’ll just cart water if it gets really bad’, or ‘we can always use temporary desalination’. But are these solutions feasible? Probably not.

“It’s because infrastructure like desalination takes time to build – it’s not something you can do in three months. That’s why it’s essential to act early, rather than waiting until storage drops to critical levels.”

Learning from the past

Beatty said that, while there’s a lot of focus on climate change today, it’s important to look beyond anthropogenic impacts: “We have paleoclimate data – from tree rings, sediment, and cave deposits – that show how much worse things can get”.

“For example, in the palaeo-climate records in Australia we’ve seen droughts lasting more than 30 years. In the western USA, research shows there were droughts that lasted centuries, far exceeding anything in the instrumental records. Fundamental and long-lasting changes in climate have impacted communities in the past.

“The Mesa Verdeans in Colorado or the Norse in Greenland, are two examples of where significant human settlements have been abandoned due to changes in climate.

“These historical events highlight that natural climate variability can be as disruptive, if not more so, than anthropogenic climate change. Routine droughts are manageable with tiered restrictions, but what happens when things escalate?

“In a mega-drought, we may need to restrict personal hygiene and bathing. Shut down automated systems, like flushing and cooling. Distribute water manually to households using containers.”

The challenges involved in these situations can be massive, Beatty said: “Imagine a scenario where we need to supply water for just 20,000 people. Even with rail and road transport, it becomes a logistical nightmare. And if the drought is widespread, where will that water even come from?”

“Temporary desalination plants aren’t the solution either. We modelled Sydney’s needs: just to supply 40% of demand, 1,000 desalination plants would be required. The environmental impact alone – such as brine discharge – would be catastrophic.”

Planning ahead

Following Beatty’s discussion, Jacobs’ Jim Fear said getting decision-makers to take proactive steps can be very challenging when the probability of an extreme event seems so small, and many of these difficulties are economic.

“Currently, water planning relies on long-term marginal cost models, which are based on the assumption that everything will average out over time. If the next water source isn’t due for 30 years, the perceived value of water is close to zero,” he said.

“But once storages drop to 5%, the value of water shoots through the roof. We need to shift from top-down planning to bottom-up thinking.

“Let’s ask decision-makers: ‘what will you do if storage reaches 5%?’ At that point, we’ll be imposing what I call refugee-level restrictions, similar to those used in refugee camps worldwide. No one wants to see Melbourne or Sydney in that situation.

“Talking about Mega Droughts that happened in the past or may happen in the future simply does not get the general public or decision makers interested enough to take action.

“It is far easier to discuss and plan for unlikely events when you are in them, so let’s start running scenarios as if we are already there. We need to spend a lot less time analysing the probabilities of unlikely events and simply ask the question, ‘what will you do when we are there and what would I have done earlier?’.

“By starting from the lowest storage levels and knowing what we are trying to avoid, the earlier we will take preventative action (such as water efficiency) as the value of water will be much greater than when the storages are full.”

As Beatty outlined, Fear mentioned again that we can’t wait until storage hits 25% to build a desalination plant: “During the Millennium Drought, Australia didn’t wait that long – we started building when storage levels dropped to 40-45%. This is the kind of proactive action we need to normalise”.

“Average cost economics assumes that we only invest in what we need most of the time. But real life doesn’t work that way. People buy SUVs even if they only go camping once or twice a year – they value convenience and flexibility. Similarly, households often have two fridges, not because they need them every day, but because they want to be prepared.

“It’s the same with water planning – we need to value water efficiency and infrastructure for the flexibility it provides, not just for average use.”

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