What is groundwater

Students learn about groundwater and its importance to WA's water supply.

Things you will need

  • Transparent container
  • Coarse gravel
  • Jug, bottle or small watering can filled with coloured water
  • Eye-dropper or plastic syringe
  • Groundwater Quiz activity sheet
About this lesson

Year level: 5, 6

Theme: Water Supply

Lesson description

  • Ask students what they think happens to the water when it rains. Where do they think it goes? 
  • Explain to students that part of the rainwater stays on the surface and part of it is absorbed into the ground 
  • Explain that the water that is absorbed into the ground becomes groundwater 
  • Watch our groundwater video

What is groundwater?

Experiment

  • Place a layer of washed gravel in the transparent container
  • Slowly pour coloured water over the gravel. Ask students to observe what happens to the water
  • Discuss how this reflects the formation of groundwater (rain falling onto the ground and soaking in)
  • Ask the students to identify the water table and recharge area in the model
  • Demonstrate how the water level moves when the container is held at an angle, thus providing an example of how the water table moves causing water to flow out into the discharge area such as the ocean or a river
  • Ask students how water could be retrieved from under the ground. Possible responses may include wells and buckets, bores and pumps
  • Explain that in some places, groundwater comes to the surface naturally and flows back into rivers. To demonstrate this, make a hole in the gravel
  • Demonstrate how water can be retrieved using an eye-dropper or plastic syringe 
  • Have students complete the groundwater quiz sheet

Reflect & summarise

Game: Above the head

Ask several students to stand with their backs to the board.  Using the key vocabulary and other groundwater related words, write a word above their heads. Students have five turns each to ask a question about their word in order to find out what it is.

Extension activities

Key vocabulary

  • Aquifer: a body of permeable rock that can contain or transmit groundwater
  • Discharge area: an area where groundwater discharges, usually to a wetland or stream, and often at a sudden change in slope
  • Recharge area: an area where rainwater soaks through the ground to reach an aquifer
  • Groundwater: the water beneath the surface of the ground, consisting largely of surface water that has seeped down
  • Water Table: the level below which the ground is saturated with water

Teacher background

Groundwater is derived from rain which percolates down through the soil or fractures in rock, filling up the pores between sand grains or the fissures in rocks. Anything from none to half of the rainfall in a given area may reach the water table and thus recharge the groundwater.

Approximately 35%-50% of the water supplied to Perth comes from groundwater supplies. Groundwater comes from huge natural reservoirs called aquifers.

An aquifer can be described as geological formations such as those composed of sand, sandstone and limestone which contain usable quantities of groundwater. The aquifer closest to the ground surface is called the shallow, or unconfined, aquifer (its upper surface is the water table) but there are also deeper confined (sometimes called artesian) aquifers where the water is confined under pressure between relatively impervious layers.

Groundwater is also used for private water supply. There are more than 150,000 domestic bores in the Perth urban area, which supply water for irrigating domestic gardens, market gardens, public open space and for industry.

Total groundwater use from private bores is almost four times the volume pumped by Water Corporation. Dams and groundwater sources are carefully managed to ensure their most efficient use throughout the year. Summer sees a peak in demand for water, mainly because people use more for watering gardens. The Department of Water regulates the volume of groundwater that can be extracted by Water Corporation.

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