Australia’s water problem is not simply “not enough rain”. It is that much of our rainfall has a very short useful life because it is lost to evaporation before it can do useful work. This article introduces “watropy” — a practical way to think about water in two dimensions: quantity (litres) and usefulness over time. By shifting our thinking from big dams alone to a combined strategy that includes micro water harvesting, we can capture more of the rain that currently escapes.
Synopsis
Entropy is a concept from thermodynamics that helped engineers understand that energy has two dimensions: quantity and usefulness. Watropy is an analogous concept for water. It says water also has two dimensions: quantity (litres) and useful life (time). It may sound abstract, but it has immediate practical implications for how we plan, store, and use water in a hot, high-evaporation country like Australia.
The irrigation conference and the water crisis
At the irrigation conference in Brisbane the sense of urgency was hard to miss. Campbell Newman, then Lord Mayor of Brisbane, described water management as dysfunctional. He pointed out that for around twenty years there had been no major new infrastructure, while population growth was driving demand up. At the same time, drought was driving supply down, creating crisis conditions.
Many speakers highlighted climate change, arguing we should not treat drought as an exception. Instead, they said planning should assume drier conditions may become normal. The theme carried through the conference, right down to discussions about urban irrigation and what water restrictions could mean for day-to-day lifestyles.
But once the rhetoric settled, the obvious question remained: where are the solutions that actually change the outcome? There was plenty of fine tuning — better sprinklers, better distribution efficiency — but little that would resolve the core problem. This is the paradox: Australia receives close to a million litres of rain per person per day, and the rainfall over our cities can exceed total urban water use, yet we capture only about 1 litre in every 2,000 litres of rain that falls.
Why we need a paradigm shift
This mismatch between “lots of rain” and “water shortages” cannot be solved by technical tweaks alone, or by political arguments about allocation. It comes back to how we think about water, and how strongly industries defend the thinking they already have.
Our water technology and assumptions are heavily influenced by colder, wetter countries with lower evaporation. Australia is different. When the environment is different, copying the same thinking produces poor outcomes. That means we need a paradigm shift — not a new gadget, but a new set of concepts that guide decisions and investment.
Paradigms are defended most strongly when they have been successful. Building dams, gravity-feeding water to cities, and sending waste water to sea is simple and cheap. Alternatives such as recycling and desalination can be expensive and complex. Change usually only happens when dissatisfaction grows to the point where “more of the same” no longer feels safe.
Dissatisfaction with paradigms: east and west
Speakers from Perth described a long-term pattern of gradually lowering rainfall. Their position was not “climate change is proven beyond debate” but rather “we must plan as if the system has changed”. That is an important mental step: dissatisfaction with the old paradigm has become strong enough to open the door to new thinking.
Interestingly, climate prediction maps also showed South East Queensland as another region likely to suffer reduced rainfall. Yet many local voices were still defending the current approach: tweak the system, build more dams, apply tougher restrictions, increase irrigation efficiency. There is a kind of logic trap in that response: if dams are nearly empty, build more dams. If the limiting factor is reliable runoff, bigger storage does not solve the cause.
Dissatisfaction is the first step, but it does not guarantee change. The next steps are harder: getting the new concepts understood, accepted, and then adopted at scale.
Where new thinking really comes from
Paradigm shifts rarely come from within large organisations. Corporate culture tends to suppress ideas that challenge the organisation’s identity and past success. Big institutions also have the resources and internal pressure to defend their position.
New ideas often come from outside — entrepreneurial thinkers — but they usually lack the power to force adoption. The typical pathway is influence: an external idea is taken up by a person inside the organisation who becomes an intrapreneur. That role takes courage. If they succeed, their career can soar. If they fail, they can be labelled a troublemaker.
With water, the need for a paradigm shift is urgent. That makes it even more important to slow down enough to think clearly, rather than charging into large projects that repeat older mistakes.
Energy, entropy, and the lesson for water
Engineers learned long ago that energy is not just “how much”, but also “how useful”. The same quantity of heat can be nearly useless in one form (such as warming a large pool by a tiny amount) and highly useful in another form (such as driving a turbine with high-temperature steam). To manage this properly, engineers needed a concept to measure usefulness. Entropy became that tool.
Entropy is not a physical substance you can buy. It is a concept. Yet it changed the real world by enabling better design, better efficiency, and better outcomes. The water industry needs a similar conceptual tool.
Why dams catch so little of our rain
We often talk as if the solution is simply “catch more water” — build more dams, expand catchments. That is the old paradigm speaking. Even in existing catchments, we capture only a small proportion of the rainfall because most rain is lost to evaporation before it becomes runoff.
In much of Australia, by the time rain arrives the surface soil is dry. It can take around 50 mm of rain to wet the soil enough before significant runoff begins. This is why droughts are so damaging. The rainfall reduction may not always be dramatic, but the usefulness of the rainfall drops sharply. The water disappears into dry soil and is then evaporated back into the atmosphere before it can fill storages.
This reveals the core issue: Australia’s problem is not only low rainfall; it is high evaporation. The rain that falls often has a short useful life.
Watropy: the useful life of water
Watropy is the idea that water has two dimensions: quantity (litres) and usefulness over time (its useful life). Drought and climate change are frightening not just because we may get less rain, but because the rain we do get may be less useful. A 20% reduction in rainfall can lead to a much larger reduction in runoff because the soil absorbs more and evaporation is higher.
Once you start thinking in terms of useful life, a critical observation becomes clear: the areas of our catchments and our cities are roughly comparable in size and therefore receive comparable rainfall. Yet city rainfall often lands on hard surfaces and runs off quickly rather than soaking into soil and evaporating. In other words, a portion of urban rainfall is potentially more “useful” — but only if we design systems to capture and store it effectively.
This is why a sensible integrated strategy matters. If the reaction to drought is only to build more large infrastructure, we risk ending up with more “almost empty” dams. The crisis is real, but repeating the past is not the same as solving the problem.
What the bush can teach us
Australia’s inland areas offer a practical lesson. In many regions evaporation far exceeds rainfall, yet vegetation exists. How? Plants survive because water is captured, transported, and stored in ways that reduce evaporation losses.
After a heavy rain, dormant seeds sprout quickly and the land becomes green. Many small plants survive by seeding before the soil dries, waiting for the next event. For larger plants, the survival story is often harsh: many trees die, but their dead roots leave channels deep into the ground. When rain returns, some water travels down these channels, moving below the surface where it is protected from direct evaporation. In some landscapes, water then hits clay or rock layers and flows sideways, creating pockets of subsurface storage that can last far longer than surface moisture.
Where the geological structure supports this, vegetation can persist. Where it does not, the landscape becomes barren. The lesson is not romantic — it is mechanical: the long useful life of water comes from getting water below the surface and shielding it from evaporation.
From gizmos to principles
You could take a “gizmo” approach and say: drill holes near trees, shape the ground, direct runoff into those holes. It may work in a local case. But we do not solve a national water problem with a few clever garden tricks. We need principles that scale.
When we look at the mechanics of dry landscapes that still support life, three principles stand out.
1) Amplification. Water is collected over a larger area and funnelled into a smaller area, effectively increasing the rainfall where plants actually grow. Some land is sacrificed so another area can be productive. Cities contain large areas of “dead land” (roofs, roads, hard surfaces) where nothing grows — potential catchment.
2) Transport. Water is moved down into the soil and then sideways through subsurface flow.
3) Subsurface storage. Water is stored below the surface, shielded from direct evaporation by the dry surface crust.
There is, in total, many times more water stored in soil than in our dams. Soil storage is cheap and effective. It is also why rivers can keep flowing long after rain has stopped.
Macro harvesting and micro harvesting
If watropy is the useful life of water, then dams are a watropy technology: they do not change the quantity of rainfall, but they extend how long water remains available to us. In a stable climate with steady rainfall, we would need fewer dams. In Australia’s variable climate, dams help bridge the time gap between rain events and demand.
We can describe dams as macro harvesting — large-scale capture and storage designed to extend water’s useful life for years. Macro harvesting delivers large volumes of relatively clean water at low per-litre cost, but it captures only a small fraction of total rainfall and becomes disproportionately ineffective when rainfall drops and runoff collapses.
By contrast, micro harvesting is local capture and storage — backyards, streets, parks, small horticulture, and small communities. Micro harvesting can gather water from light rains that never become runoff in dry catchments because it does not require wetting large areas of soil first. While each site is small, the combined potential across towns and cities is enormous because it targets the 1,999 litres out of 2,000 that currently escape.
Micro harvesting generally extends the useful life of water from a day or so (for shallow-rooted plants) to around 30 days, and longer for deeper-rooted systems. It cannot compete with multi-year dam storage when dams are full. The point is not replacement. The point is substitution: micro harvesting can reduce demand on macro water supplies, making the whole system more resilient.
This is similar to energy systems, where we use small amounts of high-grade energy for high-grade tasks and large amounts of low-grade energy for lower-grade needs. In water terms, we should stop ignoring large volumes of low-watropy water that could meet a significant share of local needs.
Why adoption is slow, even when the idea is known
Micro harvesting has been public for years. Governments and agencies are aware of it, yet adoption has been limited. The barrier is not lack of information. It is the mechanics of change.
Even after dissatisfaction with the old paradigm appears, a long path remains: acceptance of the new concepts, then actual adoption, and then widespread normalisation. During adoption, three broad behaviours usually show up.
The “crusties”. These are strongly opposed to change. They resist, complain, and attempt to block. They rarely stop change once momentum builds, but they can slow it early.
The “puddings”. These are the majority. They may agree with change in principle, but they wait until it feels safe. Then they switch quickly, which makes change appear to happen “overnight”.
The “hunters”. These actively look for better ways. Inside organisations, hunters are the people who can become intrapreneurs. They are vital, but they also face personal risk if the organisation is not ready to move.
Communal intelligence and why organisations behave oddly
Organisations have a kind of communal intelligence that is not simply the sum of individual intelligence. Modern problems are too complex for any single person, so organisations exist to process information in pieces, like a computer processing inputs through many components.
Individuals often do their part correctly, but the structure of the organisation — like software controlling hardware — shapes the final outcome. When the structure is complex and fragmented, it can lead to decisions that appear irrational, even when smart people are involved. The overlapping maze of federal and state governments, councils, water authorities, industry groups, universities, research bodies, and agencies can produce exactly that kind of dysfunction.
Protecting the organisation: the hidden objective
Most organisations claim a public objective — deliver water, build infrastructure, manage a region. But the deeper objective is often self-protection: protect authority, protect revenue, protect control, protect political safety.
In water, control is power. Ownership and control of water resources can also generate significant revenue. From that viewpoint, micro harvesting by individuals and small communities can look like a threat because it reduces dependence on central systems.
Real change is more likely when public opinion shifts. Instead of passive acceptance that “the state owns the water”, the public may come to see governments as custodians managing water on behalf of the people. When that view becomes widespread and starts to matter at the ballot box, institutional incentives can change quickly.
Where this leaves us
The key idea of watropy is simple: water management is not only about litres. It is about time — the useful life of water before it evaporates, runs away, or becomes unavailable. Australia’s water crisis is driven as much by evaporation and usefulness as it is by rainfall totals.
Macro harvesting (dams) remains essential, but it is not enough on its own in a high-evaporation environment. Micro harvesting can capture water that is currently lost and can reduce demand on dam supplies. This is not a fringe option. It is a practical complement that can increase resilience, especially in cities where rainfall often runs off hard surfaces.
If we want a real water strategy, we need more than emergency reactions. We need a shift in thinking — from litres alone to litres plus useful life. That shift is watropy.
Download ‘Watropy: A New Way to Think About Water Scarcity in Australia’ (full PDF)
