Ausgeology. Senior secondary lessons

SACE Stage 2 Earth and Environmental Science · Topic 3: Earth’s sustainable future

Water and soil.

Water and soil are renewable resources, but they last only if they are used no faster than they are replenished. Play six rounds: run the Great Artesian Basin from 1878, keep a coastal bore fresh, trace polluted groundwater to its source, plan Adelaide’s water, and clear a hillslope to see what happens to the soil.

How the game works

1 · Play the round

Each round puts you in charge of a real problem with fresh water or soil, from the Great Artesian Basin to Adelaide’s water supply. Each one has a model or a map to work with, and the facts to go with it.

2 · Meet the goals

Each round has goals, such as keeping a town’s bore fresh or bringing a spring back to life. The scoreboard keeps count. Play the rounds in order, or start anywhere.

3 · Explain

After each round, answer the check and fill in your game sheet. At the end, screen 8 asks you to decide which resources are being sustained and which are being used up, and screen 9 has eight questions.

Scoreboard

What we are learning

How water and soil are replenished over time scales from years to millennia, how to tell whether a resource is being sustained or diminished, and how human activities and natural processes change the amount and quality of fresh water.

I can

  • 1decide whether a renewable resource is sustained or diminished, from how much there is and how fast it is replenished.
  • 2explain how the rate of use changes how long the Great Artesian Basin takes to recover.
  • 3explain how pumping from a coastal aquifer can draw in sea water.
  • 4explain how rural, urban and industrial activities pollute groundwater.
  • 5describe how urban stormwater can be reused so that it is not wasted and does not pollute waterways.
  • 6compare how fast soil forms with how fast it can be lost.
  • 7explain how clearing deep-rooted plants causes dryland salinity.
  • 8discuss the sustainability of water and soil at local, regional and global scales.

SACE Stage 2 Earth and Environmental Science, Topic 3: Earth’s sustainable future. This lesson covers the first two Science Understanding statements, apart from renewable energy, which the Energy lesson covers with the third statement. The teacher notes at the end quote the statements in full.

My notebook

Printable activity

Game sheet and water budget

Three pages: a box for each round to note your results, the numbers and where they come from, then a household water budget that works out how much rain falls each year on a roof near you, and how much of a home’s water it could supply. Print one per student.

Game sheet (PDF) Editable (Word)

1Round 1

Renewable, but how fast?.

When is a renewable resource sustained, and when is it diminished?

Rain tops up Adelaide’s reservoirs every year: 82 GL a year on average over the last ten years (SA Water). New soil forms far more slowly: it can take a thousand years to form a centimetre (FAO), and in semi-arid country much longer (ANU). Both are replenished, and either can be used up if it is taken faster than it comes back.

This round · about 12 minutes

  1. Run both stores in the model. For each one, find a rate of use that keeps it sustained, and one that diminishes it.
  2. Sort ten resources by how long they take to replenish.
  3. Read the case of Alice Springs, answer the checks, and fill in box 1 on your game sheet.

The outline says renewable resources “include some that are available regularly and others that are replenished at time scales from years to millennia”. Sunlight arrives every day; the Energy lesson looks at sunlight and wind. Water and soil are the other kind. Rain refills reservoirs and aquifers, and weathering of rock slowly forms new soil.

Whether a store of water or soil lasts depends on how much is stored and how fast it is replenished, compared with how fast it is used. A store is sustained if no more is taken than comes back. It is diminished if more is taken, even while there is plenty left.

What the two stores show. The reservoirs refill within a few years once use stops, because rain brings in a large share of what they hold every year. Topsoil gains only a few hundredths of a millimetre a year, so soil lost in a century takes more than a thousand years to rebuild. Both are replenished, on very different time scales, and FAO calls soil non-renewable because its loss “is not recoverable within a human lifespan”.

Adelaide does not take all its water from the reservoirs. It also takes water from the River Murray and from a desalination plant, which makes a little every year and much more in some dry years. Round 5 shows how much comes from each.

How long does it take to replenish?

0 of 10 sorted

For each resource, choose how long it takes, on average, for its water or soil to be replaced. The feedback gives the numbers and their sources. Where the sources disagree, more than one answer is accepted.

A real case: Alice Springs

The aquifer

Water from a wetter past

Alice Springs, in the Northern Territory, has no permanent surface water, so groundwater is “the only reliable source of water” for the town. Most of it comes from the Mereenie aquifer in the Amadeus Basin, which “predominantly contains waters recharged tens of thousands of years ago under much wetter palaeo-climate conditions”.

NT Government (2026): water allocation plan, background report and water control district

Use and recharge

More out than in

In 2019 Geoscience Australia put use from the Roe Creek borefield at about 8,500 ML a year, “far in excess of the ~750 ML/yr of groundwater recharge to the area”. Groundwater levels in the borefield “have fallen by ~1 m/yr since 1964”. Rain heavy enough to recharge aquifers in the plan area comes about every seven to ten years.

Hostetler and others (2019), Geoscience Australia; NT Government (2026)

2026 to 2036

The decision

The water allocation plan declared in August 2026 “authorises a proportionately small and slow groundwater drawdown to occur over centuries”. Power and Water estimates that 300 to 400 years’ worth of water supply remains in the Amadeus Basin.

NT Government (2026), plan and Gazette S66; Power and Water

Adelaide’s reservoirs hold 199 GL and capture about 82 GL a year on average. Suppose Adelaide took all of its 166 GL a year from them. What would happen?

Alice Springs takes far more from its aquifer each year than rain puts back, yet 300 to 400 years of supply remain. Is the supply sustained or diminished?

My notebook

2Round 2

The Great Artesian Basin.

How does the rate of use change how long the basin takes to recover?

The Great Artesian Basin underlies about 22% of Australia, more than 1.7 million square kilometres of Queensland, New South Wales, South Australia and the Northern Territory, and holds about 64,900 million megalitres of water (GAB Strategic Management Plan 2020). From 1878, thousands of flowing bores were drilled into it, and most of the early ones were left to flow freely. In this round you run the basin from 1878, then decide how many bores to cap.

This round · about 15 minutes

  1. Read how the basin works.
  2. Play the model from 1878 to 1999. Watch the pressure, the bores and the springs.
  3. In 1999, choose how many free-flowing bores to cap, then play on to 2030. Try to raise the pressure and bring a spring back to life.
  4. Answer the check, and fill in box 2 on your game sheet.

How the basin works

The rocks

Sandstone under mudstone

Layers of sandstone hold the water. Above them, mudstone lets water through only very slowly, so the water below is held in under pressure: it is artesian. In the deepest central parts the sandstone aquifers are up to 3,000 m down.

GAB Strategic Management Plan 2020; Habermehl (1980)

In

Rain on the eastern margin

Where the sandstone reaches the surface along the basin’s eastern margin, rain soaks in. On average, less than 3% of the rain that falls on these recharge areas filters into the aquifers. The water then moves slowly, from less than 1 to 5 m a year, and some of it entered the ground up to 2 million years ago.

GAB Strategic Management Plan 2020; Habermehl (1980, 2015)

Out

Springs

Before bores, the water left the basin through springs and by slow leakage up through the rocks above. More than 460 spring groups support isolated wetlands, “home to species of animals and plants found nowhere else”, from mound springs in South Australia and Queensland to Cape York.

GAB Strategic Management Plan 2020; Queensland Government (2006); Landscape South Australia

1878 to the 1970s

Bores that flowed by themselves

The first bore was drilled near Bourke in 1878. Around 1918, about 1,500 flowing bores released about 2,000 ML a day. Most were left to flow into open drains, where up to 95% of the water was lost to evaporation and seepage. About 3,100 bores still flowed in the early 1970s.

GAB Strategic Management Plan 2020; Habermehl (1980); DCCEEW

The cost

Pressure and springs lost

“Only a decade into the water use expansion of the late 19th century, falling water pressures and reduced flows dashed hopes for an inexhaustible water supply from the Basin.” Pressure fell by up to 100 m in some closely developed areas, and about 40% of spring complexes became completely inactive.

GAB Strategic Management Plan 2020; Habermehl (2015); Fensham and others (2010)

1999 to today

Capping the bores

From 1999 to 2017 the Great Artesian Basin Sustainability Initiative spent $248 million: 750 bores were capped, rehabilitated or decommissioned and 21,390 km of open drains were piped, saving 250 GL a year. Queensland’s own program, which has run since 1989, reports 809 bores rehabilitated over its lifetime, saving close to 232,000 ML a year.

GAB Strategic Management Plan 2020; Queensland Government (2026)

What happened in the real basin. The model shows the pattern: the faster water was taken, the faster and further the pressure fell, and once the outflow was cut, the pressure began to climb back. In the real basin, capping and piping “has led to the stabilisation of water pressure in various aquifers and increases of water pressure in some areas of the Basin in recent decades”. The greatest recovery, north of Coonamble in New South Wales, was over 100 kPa, about 10 m of head, in a decade. In South Australia’s Far North, nine of 19 monitoring wells showed rising pressure, at 0.04 to 0.9 m a year, while seven still showed falling pressure (GAB Strategic Management Plan 2020).

How long to recover? The sources do not agree. A 2010 recovery plan for the springs reports that hydrological models predict a quick fall in pressure once extraction starts, and a new, lower pressure reached “within a time frame of several decades” (Fensham and others, 2010). The Strategic Management Plan says “Response time could be hundreds to thousands of years – well beyond planning horizons.” They may describe different things, pressure in one area or the whole basin; the sources do not say which.

About a third of the Great Artesian Basin’s bores that flowed by themselves when they were drilled have stopped flowing. Why?

My notebook

3Round 3

Sea water under the coast.

How can pumping from a coastal aquifer draw in sea water?

Under the coast, fresh groundwater lies on top of salty groundwater that comes from the sea. Pump too much from a coastal bore and the sea water moves in. In this round you run a town’s bore near the coast, then look at a real case on Eyre Peninsula.

This round · about 12 minutes

  1. Read about the 1:40 rule and two of the ways sea water gets in.
  2. Run the town bore. Make it turn salty once, then keep it fresh while pumping at least 40% through a dry decade.
  3. Read the Uley South case, answer the check, and fill in box 3 on your game sheet.

Fresh water floats on sea water

The 1:40 rule

A small difference in density

Fresh water has a density of about 1.000 g/cm³ and sea water about 1.025 g/cm³. Because of that small difference, for every 1 m the water table stands above sea level, fresh water reaches about 40 m below sea level. This is the Ghyben–Herzberg relation. So if pumping lowers the water table by 1 m, the fresh water becomes about 40 m thinner.

Barlow, USGS (2003); USGS New York Water Science Center (2017)

Two of the ways in

Inland, and up from below

Pumping lowers the water table, and the boundary between fresh and salty groundwater is drawn inland, under the land. Under a pumping bore it can also rise in a cone, called upconing. Saltwater intrusion “most often is caused by ground-water pumping from coastal wells”.

Barlow, USGS (2003)

Slow, then sudden

Hard to undo

The sea water moves slowly through an aquifer, so “many years may pass before a well that is unaffected by saltwater intrusion suddenly may become contaminated” (Barlow). Once groundwater has turned salty, “it can be extremely difficult, costly and in some cases impossible, to make it fresh again” (Werner).

Barlow, USGS (2003); Adrian Werner, NCGRT (2013)

Across Australia

Many coasts at risk

Geoscience Australia and the National Centre for Groundwater Research and Training assessed coastal aquifers around Australia. Highly vulnerable examples included Perth and Adelaide, and regional centres such as Exmouth, Derby, Bunbury and Esperance in Western Australia, Eyre Peninsula, Port Phillip Bay, and the Burdekin and Bowen areas of Queensland.

Geoscience Australia; NCGRT (2013)

A real case: Uley South, Eyre Peninsula

The basin

Most of the peninsula’s water

The Uley South basin near Port Lincoln supplies about 75% of the public water supply for Eyre Peninsula, from Port Lincoln to Cowell and up to Ceduna. Groundwater in its limestone aquifer is less than 30 years old (DEW). A model study found that from 1978 to 2012, pumping lowered the aquifer more than the climate did.

Eyre Peninsula Landscape Board (2025); DEW; Knowling and others (2015)

2023–24

The warning signs

5,578 ML was taken, 16% more than the year before. Rain at Big Swamp was 401 mm, against a long-term average of 555 mm. In the past 10 years, 82% of wells showed increasing salinity, and for 20 years water levels have stayed within 1 m of the lows that earlier raised the salinity in town supply wells.

DEW (2024)

The models

Two rates of pumping

DEW modelled a coastal well, SLE069, assuming low rainfall recharge and a high-emissions climate. Pumping 5.5 GL a year, the sea water interface rose about 7.5 m in the well; pumping 3.5 GL a year, it rose 4.45 m. Ongoing pumping of 5 GL a year gave ongoing decline in groundwater levels.

DEW technical reports 2024/4 and 2024/7

From July 2026

The decision

A new water allocation plan cuts the Uley South extraction limit from 7.3 to 3.5 GL a year from July 2027. A desalination plant at Port Lincoln, making up to 16 ML of drinking water a day, is due to deliver its first water by the end of 2026. None of the sources says sea water has reached the supply wells yet. The Eyre Peninsula Landscape Board gives declining water levels and “increasing salinity risks” as reasons for the cut.

Eyre Peninsula Landscape Board (2026); SA Water

At a bore near the coast, the water table stands 0.5 m above sea level. Using the 1:40 rule, about how far below sea level does the fresh water reach?

My notebook

4Round 4

Trace the pollution.

How do farms, towns and industry pollute groundwater?

Groundwater can carry what soaks down into it. “Industrial discharges, urban activities, agriculture, groundwater pumpage, and disposal of waste all can affect groundwater quality” (USGS). In this round you sort polluting activities, trace five polluted bores in a made-up town back to their sources, then look at real cases, mostly in South Australia.

This round · about 15 minutes

  1. Sort ten activities into rural, urban and industrial.
  2. Trace all five bores to the site the pollution came from.
  3. Read the real cases, answer the check, and fill in box 4 on your game sheet.

Pollution can come from one place, a point source such as a landfill, a leaking petrol station or a chemical spill. It can also come from a wide area, a diffuse source such as fertiliser on farmland or polluted runoff from city streets. Unconfined aquifers, with no confining layer above them, “are most at risk of pollution” (National Water Commission, 2012).

Rural, urban or industrial?

0 of 10 sorted

Sort each activity by where it mostly happens. Some fit two groups.

Real cases

Thebarton and Mile End, Adelaide

Solvents from past industry

Chemicals from historical industry, including the solvents TCE and PCE, contaminated the groundwater. These chlorinated hydrocarbons “are denser than water and leach through soil and groundwater”. Taking bore water has been prohibited since 12 December 2019.

EPA SA

Tonsley and Clovelly Park, Adelaide

Homes demolished

The EPA links TCE in the groundwater to “historical practices from the former Mitsubishi Motors and the current Monroe sites”. Twenty-three properties were predicted to have potentially unsafe levels of TCE in indoor air. Housing SA, which owned most of them, offered its tenants relocation and demolished its properties. Bore water from the upper 25 m is now prohibited.

EPA SA

Edinburgh, Adelaide; Katherine, NT

Firefighting foam

Foams containing PFAS were used to fight fuel fires at airports and Defence bases. Near RAAF Base Edinburgh, PFAS has contaminated aquifers from 0 to 60 m below ground. At Katherine, PFAS from RAAF Base Tindal “impacted the groundwater used for drinking water”, and PFAS-affected water is now treated before it enters the town supply.

Senate committee on PFAS (2025); EPA SA; Department of Defence (2025)

Mount Gambier

Septic tanks and a drinking-water lake

Sewage and septic tank effluent routinely reached the aquifer under the city before sewers were installed in the mid-1960s, polluting the groundwater with nitrate. The groundwater flows into Blue Lake, the city’s main water supply. A model estimates that from 1971 to 1997, groundwater carried 18 to 24 tonnes of nitrate a year into the lake (counted as nitrogen), by far its largest source.

Telfer (1993); Marine and Freshwater Research (2003)

Why it lasts. “Across Australia, vast quantities of groundwater fill the spaces between grains of soil or rock, and flow slowly” (Bureau of Meteorology). It moves slowly: under the Botany industrial area in Sydney, about 110 to 150 m a year (National Water Commission, 2012), and in many aquifers far less: as little as about 30 cm a year or less (USGS, 1999). Many chemicals cling to the sediments (USGS), and PFAS “do not break down readily in the environment” (quoted in the Senate committee’s report, 2025). So “restoration of a contaminated aquifer is difficult and may require years, decades, centuries, or even millennia” (USGS). The national guidelines add that “the costs of remedial measures are generally many times the costs of prevention”.

In South Australia, the EPA can declare a groundwater prohibition area, where using bore water can bring a fine of up to $8,000. At Thebarton, the EPA warns against drinking contaminated bore water or cooking with it “(even when boiled)”. The 18th prohibition area in the state, at Athol Park, was declared in October 2026. “Rainwater and mains water (tap water) are not affected” (EPA SA).

A bore has benzene in its water. A service station stands 800 m away. Which evidence best supports the service station as the source?

My notebook

5Round 5

Water for a city.

Where does Adelaide’s water come from, and how can stormwater be put to use?

Adelaide’s water comes from reservoirs in the Mount Lofty Ranges, from the River Murray and from a desalination plant. How much comes from each changes with the rain. In this round you plan four years of supply, then follow stormwater through a wetland and an aquifer in Salisbury.

This round · about 18 minutes

  1. Read the chart of where Adelaide’s water came from.
  2. Plan the supply for four real years. In 2019–20, leave Murray water for farmers upstream.
  3. Step through what happens to stormwater in Salisbury, and work out the rain on a roof.
  4. Answer the two checks, and fill in box 5 on your game sheet.

Where Adelaide’s water came from

Data
Show the numbers as a table

Water supplied to Adelaide’s urban system each year, in gigalitres, for years ending 30 June. Reservoirs are the local surface water storages; River Murray water is pumped to Adelaide through pipelines. Data: Bureau of Meteorology, National Water Account 2023 and 2025, Adelaide.

The Water Security Statement 2022 says the reservoir catchments provide 60% of metropolitan Adelaide’s mains water in an average year. “When it is dry in the Mount Lofty Ranges, Adelaide sources most of its water from the River Murray.” In the eight years in the chart, the reservoirs supplied between 18% and 66% of the water, and 44% in 2022–23, a year with above-average rain (Bureau of Meteorology). The desalination plant at Lonsdale, running since 2011, can make up to 100 GL a year, about half of Adelaide’s yearly demand. It was built after the Millennium Drought to give a supply “not dependent on rainfall” (Water Security Statement 2022; Bureau of Meteorology). It cost about $1.83 billion to build (TRILITY), it had used $120 million of electricity by 2017 (Australian Water Association, reporting the Auditor-General), and in most years it runs in “a minimum production mode” (Government of South Australia, 2025).

2024–25 was the driest year on record in the Adelaide region: 361 mm of rain, against an average of 629 mm. Desalinated water rose more than fivefold, to 26.5 GL (Bureau of Meteorology).

Look at the chart. Why did Adelaide take 135.7 GL from the River Murray in 2018–19, but only 51.3 GL in 2017–18?

Stormwater

Roofs, roads and paving stop rain soaking in, so “the volume of stormwater runoff increases with urban development” (Senate committee, 2015). The EPA estimates that 62.9 GL of stormwater, 93% of it, is discharged to the environment every year. On the way it can pick up “litter, organic matter, oils, plastics, toxicants and sediments”, and off Adelaide more than 5,000 hectares of seagrass have been lost (EPA SA). The City of Salisbury catches some of its stormwater runoff, cleans it, and stores it underground until it is needed.

How does Salisbury’s scheme stop stormwater being wasted, and stop it polluting the sea?

My notebook

6Round 6

Soil and salt.

Why is soil lost faster than it forms, and how does clearing bring salt to the surface?

Soil forms very slowly, and erosion can strip it away far faster. Clearing the land can also raise salty groundwater until salt kills the crops. In this round you compare the rates, then clear a hillslope and watch what happens over the following decades.

This round · about 15 minutes

  1. Read the chart of how long soil takes to form, and how fast it can be lost.
  2. Clear the hillslope in the model and find when salt reaches the surface. Then replant the upper slope instead.
  3. Answer the check, and fill in box 6 on your game sheet.

Formed slowly, lost quickly

Data
Show the numbers as a table

Each bar is the time to form, or to lose, 1 cm of soil, worked out from the rate each source gives: for example, 1 mm a year means 10 years for 1 cm. Soil forms at different rates in different places: faster in the wet Atherton Tableland than in the semi-arid country near Hughenden (ANU). These are estimates, and the sources do not agree.

Erosion rates from conventionally ploughed fields “average 1–2 orders of magnitude greater than rates of soil production”: 10 to 100 times faster (Montgomery, 2007). The same study found that no-till farming, which sows crops without ploughing, cut erosion by 2.5 to more than 1,000 times, with a median of 20 times. In South Australia, no-till sowing of annual crops rose from 16% in 1999 to 83% in 2016 (EPA SA).

How much soil is at risk

Global

A third degraded

“Erosion carries away 25 to 40 billion tonnes of topsoil every year”, and 33% of land is moderately to highly degraded (FAO, 2015). The UN’s Global Land Outlook puts the share of land degraded or degrading at between 20 and 40% (2022).

FAO (2015); UNCCD (2022)

Eastern Australia

Red Dawn, 2009

On 23 September 2009, a dust storm 3,000 km long reached Sydney, with dust from the red sandplains of western New South Wales and the Channel Country of Queensland. An estimated 2.54 million tonnes of sediment was lost off the coast.

Leys and others (2011)

South Australia

Farmland at risk

About 5.4 million hectares of agricultural land (61%) is susceptible to wind erosion and 2.9 million hectares (32%) to water erosion. Around 1.5 million hectares of cleared farmland is affected by dryland salinity, most of all in the Upper South East and parts of Eyre Peninsula.

EPA SA, State of the Environment 2023

Salt from the rain

Over millennia, wind has carried salt inland from the sea and rain has dropped it on the land, where it has built up in the clay and weathered rock below the soil. A typical hectare of the Wheatbelt in Western Australia holds 170 to 950 tonnes of salt down to 40 m (Parliament of Australia, 2004). Native plants with deep roots use most of the rain. When they are cleared for shallow-rooted crops and pastures, more water soaks past the roots, so the water table rises, bringing the salt with it. Near the surface the water evaporates and the salt is left behind.

Salt in the River Murray. Salty groundwater seeps into the River Murray naturally, but clearing and irrigation have sped up the flow of salt into the river (Landscape South Australia). In the early 1980s, salinity at Morgan was above 800 EC for 18 months in a row, with a peak of 1,400 EC (Hart and others, 2020). Salt interception schemes now pump salty groundwater away from the river into basins where it evaporates (DEW, 2016). South Australia’s seven schemes intercepted an estimated 299,458 tonnes of salt in 2024–25, and Morgan stayed below its 800 EC target (DEW, 2025).

Why can clearing native bush for wheat bring salt to the surface of a valley, sometimes decades later?

My notebook

8All six rounds

Putting it together.

Which water and soil resources are being sustained, and which are being used up?

Each round looked at one resource. Now judge them together: for each one, compare how much there is and how fast it is replenished with how fast it is used. Then sort the issues by scale, from one suburb to the whole planet.

Sustained or diminished?

0 of 9 sorted

Decide whether each resource is being sustained or diminished over time. Two can be argued either way.

Local, regional or global?

0 of 9 sorted

Sort each issue by the scale it works at: a suburb or a farm, a region such as a river basin or part of a continent, or the whole world.

Key idea

A renewable resource is sustained only while it is used no faster than it is replenished. Rain refills reservoirs within years; aquifers can take centuries or more, and soil forms over thousands of years, so the slower the replenishment, the easier it is to diminish. Fresh water can also be spoiled by sea water and pollution, which can take decades to centuries to put right.

My notebook

9Show what you know

Show what you know.

Eight questions, one for each of the I can statements on screen 1. You get one try at each, so think before you tap.

An aquifer holds 500 GL. Rain recharges it by 20 GL a year, and 35 GL a year is pumped out. Which statement is correct?

Which statement about the Great Artesian Basin is best supported by the evidence?

A town bore near the coast pumped fresh water for 20 years. Then pumping was doubled, and a few years later the water turned salty. Why?

Which pair correctly matches an activity with the way it pollutes groundwater?

A council wants its stormwater to be used, and to stop it harming the seagrass offshore. Which plan does both?

A ploughed field loses soil at about 1 mm a year, and soil forms at about 0.07 mm a year. About how long would 10 cm of topsoil last?

A farmer cleared the deep-rooted bush on a hill and planted wheat. Twenty years later, the valley below shows no salt, so the farmer says clearing did no harm. What is wrong with this conclusion?

Which of these is a global-scale issue for water or soil?

Printable activity

Game sheet and water budget

Three pages: a box for each round to note your results, the numbers and where they come from, then a household water budget that works out how much rain falls each year on a roof near you, and how much of a home’s water it could supply. Print one per student.

Game sheet (PDF) Editable (Word)
For teachers

Curriculum

SACE Board of South Australia, Stage 2 Earth and Environmental Science Subject Outline (accredited for teaching at Stage 2 from 2018, reissued for 2025), Topic 3: Earth’s sustainable future. NT students take the subject as part of the NTCET. The topic outline says:

In this topic, students explore how increases in human life span and greater use of scientific and technological knowledge have increased the global demand for energy, water, and soil resources. They recognise why provision of good-quality fresh water and groundwater at local and global levels will continue to be of high importance into the future.

The topic has three Science Understanding statements. This lesson covers the first two, except the first statement’s dot point on renewable energy. That dot point and the third statement are covered in the Energy lesson.

Renewable resources include some that are available regularly and others that are replenished at time scales from years to millennia.

  • Discuss the need for, and limitations of, renewable sources of energy, including biofuels, solar, wind, and geothermal energy.
  • Determine whether a renewable resource is either diminished or sustained over time, given the abundance of the resource and how readily it can be replenished.
  • Investigate how the timescale required to replenish a large groundwater system, such as the Great Artesian Basin, is influenced by the rate of depletion of the system.
  • Discuss the sustainability of soil and water at local, regional, and global scales.

The availability and quality of fresh water can be influenced by human activities, and natural processes at local and regional scales.

  • Discuss how stormwater run-off in urban areas may be recycled for community use so that it is not wasted and does not pollute waterways.
  • Explain how overextraction of groundwater from near-coastal aquifers may cause inflow of sea water.
  • Explain how pollution of groundwater can result from a variety of rural, urban, and industrial activities.

The effective use of energy resources is constrained by factors including waste disposal, and the efficiency of available technologies to collect, store, and transfer the energy.

  • Compare the advantages and disadvantages of using renewable and non-renewable energy resources.

Where the lesson covers them:

  • Renewable resources replenished at time scales from years to millennia, and sustained or diminished: round 1 (a model of Adelaide’s reservoirs and of topsoil, a sort of ten replenishment times, and the case of Alice Springs’ groundwater), with every later round returning to the idea, and screen 8 (a sort of nine resources as sustained or diminished).
  • The Great Artesian Basin: round 2 (a model of the basin from 1878 to 2030, tuned to the history of bores and flows, in which students choose how many bores to cap, with the real recovery and the sources’ disagreement about how long it takes).
  • Sustainability of soil and water at local, regional and global scales: rounds 5 and 6, the second sort on screen 8, and exit question x8.
  • Stormwater recycled for community use: round 5 (Salisbury’s wetlands and aquifer storage and recovery, in five steps, with the seagrass loss in Gulf St Vincent).
  • Overextraction from near-coastal aquifers: round 3 (a coastal aquifer model with the 1:40 rule, and the Uley South case on Eyre Peninsula).
  • Pollution of groundwater from rural, urban and industrial activities: round 4 (a sort of ten activities, a map game tracing five bores to their sources, and South Australian cases).

The lesson also uses these of the outline’s possible contexts:

Investigate the drains and bores in use in areas that recycle stormwater run-off.

Discuss how urbanisation, overextraction, pollution, siltation, drought, and algal blooms affect the availability and quality of fresh water.

Investigate and report on the sources and costs of water for domestic use at students’ own locality, and how these may have changed over time. Obtain data to calculate and report on the volume of rainwater that falls annually on a typical house roof in a local district.

Evaluate the benefits and limitations of using desalination of sea water to provide a viable water resource.

Sketch or photograph examples of dryland salinity or erosion to illustrate a negative impact of human activity on sustainability of resources.

Round 5 and the game sheet cover the first and third (Adelaide’s sources since 2017–18, and a roof in the school’s district); rounds 3 to 6 touch on all of urbanisation, overextraction, pollution, siltation (the seagrass loss) and drought, though not algal blooms; round 5 gives the data to weigh up desalination; and round 6 can be followed by a sketch or photograph of salinity or erosion near the school.

Science as a human endeavour runs through the lesson. Its key concepts in the outline include these, used in the rounds shown:

Collaboration between scientists, governments, and other agencies is often required in scientific research and enterprise.

Round 2: the Great Artesian Basin Sustainability Initiative, run by the Commonwealth and the Basin states with landholders; round 3: the national seawater intrusion assessment by Geoscience Australia, the NCGRT and state agencies.

Scientific knowledge, understanding, and inquiry can enable scientists to develop solutions, make discoveries, design action for sustainability, evaluate economic, social, cultural, and environmental impacts, offer valid explanations, and make reliable predictions.

Round 3: DEW’s groundwater models of Uley South, used to set a new extraction limit before sea water reaches the supply wells; round 5: wetlands and aquifer storage and recovery; round 6: no-till farming and salt interception schemes.

The use of scientific knowledge may have beneficial or unexpected consequences; this requires monitoring, assessment, and evaluation of risk, and provides opportunities for innovation.

Round 2: flowing bores that opened up inland Australia but lowered the pressure and dried springs; round 4: solvents and firefighting foams that once seemed safe; round 6: clearing for crops that raised salty water tables decades later.

Science informs public debate and is in turn influenced by public debate; at times, there may be complex, unanticipated variables or insufficient data that may limit possible conclusions.

Round 2: how long the Great Artesian Basin takes to recover, from several decades to hundreds or thousands of years depending on the source; round 3: acting on modelled risk before there is evidence of sea water in the supply wells.

Assessment design criteria the tasks give practice for: KA1 and KA2 (the checks, sorts and game sheet), KA3 (weighing up capping at round 2, the Uley South decision at round 3 and desalination at round 5), KA4 (the explanation on screen 8), IAE2 and IAE3 (the water budget on the game sheet, and reading the data in rounds 2, 5 and 6) and IAE4 (the limits of each model, stated under it).

How the lesson is taught

The lesson is a game in six rounds. Each round puts students in charge of a real problem with a model or a map, sets goals, and gives feedback as they play; the scoreboard on screen 1 keeps count. Clark, Tanner-Smith and Killingsworth (2016) reviewed studies of digital games for learning and found that “digital games significantly enhanced student learning” compared with non-game conditions (g = 0.33). Versions of games with added design features gave a further benefit (g = 0.34). The goals here are tied to the curriculum, and each round ends with a check and a box on the game sheet, so the play leads back to the science.

  • Timing. About two hours in all: three 50-minute lessons, or two 60-minute lessons with the notebook questions for homework. Lesson 1: screen 1 together (the notebook questions and how the game works), then rounds 1 to 3. Lesson 2: rounds 4 to 6. Lesson 3: screen 8 in pairs, a class discussion of which resources are sustained, screen 9, and the water budget on the game sheet.
  • Pairs or alone. Pairs work well: one runs the model while the other reads the facts and keeps the sheet. Students can play the rounds in any order; the scoreboard shows which goals are met.
  • Discussion points. After round 2, ask why a basin holding 64,900 million ML can still be harmed. After round 5, ask whether desalination makes Adelaide’s water sustainable, and what it costs in energy and money; the outline suggests investigating a desalination plant’s energy use and cost.
  • The game sheet has a box for each round and a household water budget for the school’s own district. Collect it as evidence of learning; the water budget gives IAE2 and IAE3 practice.

Handle with care

  • Some students may live in a groundwater prohibition area, or near a contaminated site. Keep to the EPA’s facts: “Rainwater and mains water (tap water) are not affected”, and the EPA SA website lists every area and its advice. Avoid naming businesses beyond what the EPA has published.
  • Some students come from farming families. Dryland salinity and erosion followed from how land was cleared and farmed over generations, often with what was then thought best practice. Round 6 shows the responses too: no-till sowing rose from 16% to 83% of annual crops in South Australia between 1999 and 2016 (EPA SA).
  • The Great Artesian Basin’s springs are places of permanent water “with widely recognised cultural, spiritual and subsistence importance to Indigenous people for tens of thousands of years” (Habermehl, 2020). The lesson does not tell any story about them. If you discuss them, follow your school’s protocols and, where you can, the guidance of local Aboriginal communities.
  • Water restrictions, drought and the cost of water can be worries at home. Keep the focus on evidence and on the responses the rounds show: capping bores, new extraction limits, desalination and stormwater reuse.

Misconceptions the rounds target

  • Renewable means it cannot run out (rounds 1 and 2, screen 8). A renewable store is diminished whenever it is used faster than it is replenished, however large it is.
  • A resource is only diminished once it is empty (round 1, x1). It is diminished as soon as it shrinks over time.
  • The Great Artesian Basin has nearly run out of water (round 2). It still holds about 64,900 million ML. The amount stored fell by only a tiny fraction, but the pressure fell a long way, and that stopped bores and springs flowing.
  • Groundwater is an underground lake or river (rounds 2 to 4). It fills the pores and cracks in rock and sediment and moves slowly, from centimetres to more than 100 m a year depending on the aquifer (USGS; National Water Commission), and from less than 1 to 5 m a year in the Great Artesian Basin (GAB Strategic Management Plan 2020).
  • Sea water gets into a coastal bore from the surface (round 3, x3). It moves through the aquifer, inland and up from below, when pumping lowers the water table.
  • Pollution spreads out evenly in all directions from where it is spilt (round 4). It moves with the groundwater, down-gradient, as a plume.
  • Boiling makes contaminated bore water safe (round 4). The EPA warns against using it even when boiled.
  • Desalination makes a city’s water supply independent of the environment (round 5). It is independent of rainfall, but it uses energy and costs money, and in most years the plant runs at a low rate.
  • Salt in dryland salinity comes from irrigation or fertiliser (round 6, x7). Most of it came from the sea in rain over millennia and was stored below the soil; clearing brings it up.
  • Soil is renewed every year by ploughing (round 6). Ploughing moves soil but does not make it; new soil forms from rock over about a century to tens of thousands of years per centimetre.

About the data and the models

  • Alice Springs (round 1): the sources measure recharge and decline in different ways and over different areas. Recharge to the Roe Creek area is about 750 ML a year against about 8,500 ML of use (Hostetler and others, 2019), and Power and Water estimates that only 20 litres of every 100 used is renewed each year. Water levels fell by about 1 m a year at Roe Creek from 1964 (Hostetler and others, 2019), and Power and Water gives about 0.6 m a year.
  • Adelaide’s water (round 5): Bureau of Meteorology, National Water Account 2023 (Table S9) and 2025 (Table S14), Adelaide, water supplied to the urban system for years ending 30 June. The 2023 account covers 2017–18 to 2022–23; the 2025 account gives 2023–24 and 2024–25. In the game, each year’s demand is the total supplied, and the reservoirs’ share is what they actually supplied.
  • Rainfall (round 5 and the game sheet): Bureau of Meteorology mean yearly rainfall, read on 2 November 2026: Adelaide (West Terrace / ngayirdapira) 525.8 mm, 1839–2026; Kent Town 547.1 mm, 1977–2020; Adelaide Airport 435.0 mm, 1955–2026; Parafield Airport 445.4 mm, 1929–2026; Mount Lofty 963.2 mm, 2009–2026. No source gave a typical roof area, so 150 m² is labelled as an example. The loss factor, 0.7, is from a South Australian rainwater tank fact sheet (2003) hosted by the City of Burnside. Household use, 210 kL per property in 2024–25, is from the Bureau of Meteorology’s National performance report 2024–25.
  • The Great Artesian Basin model (round 2) is one aquifer with bores standing at different heights, tuned so that its flows match about 2,000 ML a day around 1915 to 1918 and about 1,500 ML a day in the early 1970s and in 2006 (Habermehl, 1980; Queensland Government, 2006), and its numbers of flowing bores match about 1,500 around 1918 and about 3,100 in the early 1970s (Habermehl, 1980). Its pressure is illustrative. It starts at 140 m, a little above the highest head measured at ground level (about 130 m, Queensland Government, 2006), and falls by about 100 m by the 1990s, like the largest falls recorded in closely developed areas (80 to 120 m, depending on the source and date), not the basin average. The model caps no bores before 1999, although 628 had been controlled before GABSI began (Sinclair Knight Merz, 2014). Like the hydrological models cited in 2010, it settles within decades, so its time to recover after capping is a property of the model, not a forecast.
  • The coast model (round 3) uses the Ghyben–Herzberg relation for the interface, with a steady flow of fresh water to the sea, and a cone of sea water under the bore. The pumping and recharge numbers are examples. The Uley South numbers are DEW’s.
  • The pollution map (round 4) is a made-up town; the plumes grow at about 40 m a year, and the lab results are described in words. The real cases are from EPA SA, the Department of Defence and published studies.
  • The soil chart (round 6) converts each source’s rate into years for 1 cm; the arithmetic is shown under the chart. The salinity model uses example numbers, chosen so that salt appears within the 10 to 100 years that DPIRD gives for local groundwater systems to adjust after clearing.
  • Where the sources disagree, the page or these notes say so. Water lost from bore drains: up to 95% (DCCEEW; Habermehl, 2015), more than 95% (GAB Strategic Management Plan 2020), and up to 90% or 80% in other sources; the page uses up to 95%. How long the Great Artesian Basin takes to recover: several decades (hydrological models cited by Fensham and others, 2010) or hundreds to thousands of years (GAB Strategic Management Plan 2020); the page gives both. Queensland’s rehabilitation program (809 bores since 1989) and GABSI (750 bores, 1999 to 2017) overlap in time, so their totals should not be added. The largest pressure fall in the Great Artesian Basin: up to 80 m to 1970, 100 m to the 1990s or 120 m, depending on the source and date. Seagrass lost off Adelaide: more than 5,000 hectares (EPA SA), over 6,000 hectares from 1949 to 2007 (2016 report card) or over 6,500 hectares since 1949 (Goyder Institute). The page uses EPA SA’s figure, which is the loss that led the EPA to set up the Adelaide Coastal Waters Study in 2001, so it is the oldest of the three. How fast soil forms: FAO says up to 1,000 years per centimetre, while a 2022 UN News report gives a few centimetres in about 1,000 years. Dryland salinity in South Australia: around 1.5 million hectares affected (EPA SA, 2023), against 390,000 hectares with a high potential to develop it in 2000 (National Land and Water Resources Audit, via the ABS); the two measure different things, and neither explains the gap. The reservoirs’ share of Adelaide’s water: 60% in an average year (Water Security Statement 2022), but between 18% and 66% in the eight years of the Bureau of Meteorology’s accounts on the page, including 44% in 2022–23, a year of above-average rain; round 5 gives both. Stormwater: the EPA’s State of the Environment 2023 says 62.9 GL of stormwater (93%) is discharged to the environment each year, while another page of the same report says only 4.4 GL of 140 GL of stormwater and urban watercourse water is reused; the page uses the first.

Answers at a glance

  • Round checks: q-renew, diminished, dry within three years; q-alice, diminished, even though it will last for centuries; q-gab, the pressure fell below the ground the bores stand on; q-coast, 20 m; q-poll, up-gradient and petrol contains benzene; q-city, the reservoirs supplied far less; q-sw, wetlands, aquifer storage and parks; q-soil, crops use less water so the salty water table rises.
  • Round 1 model: the reservoirs are sustained at up to 82 GL a year and run dry in the third year at 166 GL; topsoil is sustained only below 0.07 mm a year, and at 1 mm a year it is gone in about 108 years and takes about 1,400 years to rebuild.
  • Replenishment times: air and rivers, days or weeks; soil moisture, months to a year (or days or weeks); lakes, groundwater on average, Uley South and a tropical forest, years to centuries; the ocean and the Great Artesian Basin, thousands of years or more; topsoil, years to centuries or thousands of years.
  • Round 2 model: about 1,200 bores flowing and 1,950 ML a day in 1910, pressure down 47 m; about 3,000 flowing bores and 1,460 ML a day in 1999, pressure down 102 m, with three of five springs still flowing. Capping 60% by 2017 raises the pressure to about 50 m above ground by 2030 and brings a fourth spring back.
  • Round 3 model: with normal rain, the bore 900 m inland stays fresh up to 75% pumping and turns salty at 80%. In a dry decade it turns salty at 40%, so to keep pumping 40% the town must move its bore at least 1,100 m inland.
  • Rural, urban or industrial: fertiliser and manure, rural; septic tanks, rural or urban; fuel tank and stormwater, urban; landfill and dry cleaner, urban or industrial; degreasing with TCE, firefighting foam and acid drainage, industrial. The map: A, the houses on septic tanks; B, the service station; C, the dry cleaner; D, the metal works; E, the fire-training ground.
  • Round 5 game: any mix within 3 GL of the demand counts; 2019–20 needs about 33 GL or more of desalination to keep the Murray below 100 GL.
  • Round 6: soil is lost 10 to 100 times faster on a ploughed field than it forms (Montgomery, 2007). The salinity model shows salt after about 40 years; replanting the upper slope at year 10 stops the rise, and the water table falls back slowly.
  • Screen 8: reservoirs and Salisbury’s aquifer storage, sustained; the Great Artesian Basin to the 1990s, Uley South, ploughed topsoil, the High Plains aquifer and fossil water, diminished; the Great Artesian Basin since capping, and topsoil on a no-till field, either, with reasons. Scales: Salisbury, Athol Park and a rainwater tank, local; Uley South, the Great Artesian Basin, the River Murray and Red Dawn, regional; topsoil erosion and the groundwater footprint, global.
  • Exit check: x1 diminished, 15 GL a year; x2 pressure fell fast, recovery slow; x3 the water table fell; x4 septic tanks; x5 wetlands, aquifer and pipes; x6 about 110 years; x7 the water table may still be rising; x8 the groundwater footprint.

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References

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Sources

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