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Water use and distribution

This resource is about how the Murray–Darling Basin’s water is made available and used by people in Australia.

Australia has very low rainfall (except seasonally in the tropics); and this rainfall is very variable season-to-season and year-to-year. This means we can’t depend on a reliable supply.

Most of the runoff bringing water into the Murray–Darling Basin river system falls on less than 15% of the land area — except in relatively rare times of flood. Yet the Murray–Darling Basin is Australia’s most important food and fibre growing region.  Students will learn how this is achieved through the use of infrastructure and water management policy. They will also learn about the different uses of water.

Outcomes

By the end of this resource, students will understand:

  • the distribution of water to different uses, states and sectors;
  • The amount of water used compared to the amount available;
  • different sources of agricultural water;
  • the way water is categorised for different uses.

Curriculum focus

  • ACHGK040 – The nature of water scarcity and ways of overcoming it.
  • ACHGK037 – Classification of environmental resources and the forms that water takes as a resource.
  • ACSIS107 – Construct and use a range of representations, including tables and graphs, to represent and describe observations, patterns or relationships in data using digital technologies as appropriate.

Preparation

  • Print student worksheets
  • Prepare to show YouTube video
  • Download ABS pages (to show on Smartboard) if students do not have access to individual devices.

Engage with the topic

Students watch the video and complete questions 1 to 6 on the worksheet.

If time is short the video can be stopped at 7:10.

Explore the topic

Year 7 students should first draw a predictive bubble diagram (point 7 on worksheet) giving comparative sizes for how much water they think is consumed by agriculture, the environment and domestic use for people. They then explore real data and compare to their prediction.

The following activities can be done in groups, and students can either work through the exercises one by one, or focus on one topic and present back to the class.

Topic

Teacher notes

Student worksheet answers

Australia’s water use and distribution

Water Account, Australia, 2013-14

Using the standard graphs that appear, students investigate and answer the following questions on their worksheets. They may need assistance to hover over graphs and understand scales of measurement.

  1. Which state is the biggest water user?
  2. Which sector uses the most water?
  3. Which sector is paying the most for the water used?
  4. Which state’s agricultural use is highest?
  5. What can be said about the area of irrigated land over the period 1920 to 2006?

Question 8.

  1. NSW
  2. Agriculture
  3. Households
  4. NSW
  5. Continued growth from 170 to 2,546,000 ha.

Agricultural water use

Water use on Australian farms by state/territory and MDB region .

Using the Australian Bureau of Statistics 4618.0 Water Use on Australian Farms 2013-14 page, ask students to scroll down to the charts.

They record (Q. 8 on their worksheet):

  1. How much water was applied in Australia for agriculture over the year?
  2. How much of this was in the Murray–Darling Basin?
  3. What percentage is that of the total?
  4. What percentage of all agricultural water use in the Basin was for irrigation?

NB. A ‘water year’ runs from July to June

Question 9.

  1. 11,561,900 ML = 11562 GL
  1. 8,024,700 ML.
  2. 69%
  3. 96% (calculated by dividing MDB irrigation water use by total water use MDB)

Elaborate

Topic

Teacher notes

Student worksheet answers

Comparing water availability to use

Students view a diagram (point 11 on their worksheet) that explains water cycles in the Basin.

(Note: The ABS charts are in megalitres. Divide by 1000 to get gigalitres).

The Basin receives about 530,000 GL of inflow per year (530,000,000 ML). Explain to students, if needed, how data has been collected for around 120 years (by measurements at gauges all around the Basin’s rivers). When all the measurements are added up and divided by the number of years, we get the average.

In 2012–13, rainfall was generally ‘average’ to ‘below average’ (particularly for the north). BUT because there was above-average rainfall for the period January to June in the south, irrigation demand for water in late summer wasn’t as high as it has been in other years. For the whole year 2013–14, the total amount of rainfall that ended up in the Murray–Darling Basin rivers was 5670 GL.

Climate experts believe that we are going to see a drying trend.

Question 10:

Students demonstrate their understanding by returning to their bubble diagram prediction and comparing it to what they learned through investigating ABS data.

Q.11. Students demonstrate their learning by interpreting a diagram and what they learned from the ABS data.

Using more water in a year than inflow

Students again refer to the ABS sources of agricultural water data.

More water can be used in drier years than was recharged by rainfall over that year. Some water remains in storages from previous years & can be delivered via irrigation channels; some comes from farm dams, some from groundwater.

They then research the MDBA’s website groundwater page and read the first few paragraphs to find out why reliance on groundwater can be a problem (recharge rates are very slow – it is a non-sustainable resource).

Question 12:

All the average annual inflow can be captured in the Basin’s dams in many years.

Question 13:

  1. More water was used for agriculture than inflow in that year.
  2. Students demonstrate what they learned by predicting how this could happen.
  3. Groundwater, on farm dams and tanks, irrigation channels.

Question 15: students demonstrate their overall understanding by explaining the likely water availability for the environment or recreation.

Ask students to think back to the video where they learned in the video that Australian irrigators are among the most efficient in the world. They are using good technology to keep water use down.

Assessment

Year 7 students analyse all the information and infer water availability (and potential issues) for things other than industrial, agricultural and town use (e.g. the environment, recreation).

Older students could carry out independent research on the above topics – that is:

  • use science inquiry skills to collect, analyse and communicate primary and secondary data on resource extraction and related impacts on Earth systems
  • evaluate, with reference to empirical evidence, claims about resource extraction and related impacts on Earth systems and justify evaluations.

For example, researching the effects of the ‘millennium drought’ (2000–2009) in the Murray–Darling Basin, the subsequent legislation; how it has been received by industries, communities and environmental advocates; and whether it ensures sustainable use of water.

Relevant resources:

Continue to Water quality