Theme 3: Human Impacts on Catchments

Topic: Water Supply

Note: See also Murray-Darling Basin and Mt Lofty Ranges Catchments.

There are two main water sources for South Australia - the Mt Lofty Ranges and the River Murray. There are also many other important ground and surface water resources. More than two thirds of the State's population, including primary producers, various industries, local communities and metropolitan Adelaide, depend on water from the Mount Lofty Ranges. This region is the major water catchment for Adelaide's water supply and in an average year, 60% of Adelaide's domestic water supply comes from streams in the Mount Lofty Ranges. In the western Mount Lofty Ranges, there are 10 urban water supply reservoirs with a total capacity of about 200,000ML. There are also about 11,800 farm dams and 6,750 wells.

Water from the River Murray plays a critical role in the life and economy of much of South Australia. On average, 52% of all water used in the State comes from the Murray. It is the main source of water for Adelaide, supplied by the Mannum-Adelaide (67 km) and Murray Bridge-Onkaparinga (48 km) pipelines. On average, metropolitan Adelaide receives some 42% of its water from the Murray and up to 90% in drought years. Two pipelines take water from Morgan to the northern Spencer Gulf, 'Iron Triangle' industrial towns of Port Pirie, Port August and Whyalla (359 km), with a line further north to Woomera. With some 90% of their water coming from the Murray, these towns and their industries would not exist without the pipelines. Two other pipelines serve large rural areas of the state, Swan Reach-Stockwell (53 km) and Tailem Bend- Keith (143 km).

What decisions have been made to maintain secure water supplies?

To ensure a drinkable water supply into the future, a balance must be struck between consumption and conservation of water in the rivers of the Murray-Darling Basin. Measures include: diversions being capped; an interim moratorium being introduced immediately on further increases in diversions while the precise details of the long-term cap are established; and the community being more informed of water saving measures.

In the Mount Lofty Ranges, a process is in place to ensure sustainable long-term management of the water resources. For further information about the management process, see: www.dwlbc.sa.gov.au/subs/wmlr/index.html

How much of the world's water supply is fresh water?

Less than 1% of the world's water supply is available for human use. This equates to approximately 1 teaspoon of water out of a full bath-tub or 0.007%.

What are the main water users in South Australia?

The main water use is irrigation (about 75%), with urban and industrial use accounting for about 20%.

Does all water reach it's source?

No - In all water supply or distribution systems there are transmission losses due to various causes, such as leaking pipes, evaporation, and seepage to groundwater from canals. In other words, not all water reaches its intended place of consumption.

Student Activity Ideas

Create a series of pipes/water courses in the open air, from different materials and see which one allows the most water to reach a set destination. (e.g. soil, wood, metal, open and closed pipes)

Enquiry Learning

• What do we use water for?
• What types of infrastructure and investment is required to supply water for our needs?
  • Domestic use of water: How does the water supply reach the tap in drinking condition?
  • Industrial/commercial uses such as power plants, market gardens, cooling machinery and others.
  • Recreational uses such as fishing, skiing, watering playing fields and golf courses. Government water management, (including watering regimes and water management infrastructure - gardens and reserves, wetlands, roadside verges, new housing and industrial developments).
• What practices and technologies are being adopted to protect and restore water quality and catchments?
  • Constructed wetlands.
  • Aquifer storage and recharge.
  • Water saving devices.
  • Biodiversity protection.
  • Water conservation measures.
• Why is South Australia so reliant on the Murray River and the Mount Lofty Ranges watershed for water supply?
• Why do degraded catchments create greater expense in supplying and treating water for consumption, industry, irrigation and recreation?
• What are the impacts of weirs and dams in the Murray River and the Mount Lofty Ranges watershed?

Internet Resources

Type	Description	Resources Covering the Topic
Easy	Murray water use. Looks at the vital role the Murray plays in providing water for South Australia and other States.	Murray-Darling Basin Commission www.mdbc.gov.au/river_murray/ river_murray.htm
	Managing the water cycle. Brief overview of managing water supply.	Sydney Water www.sydneywater.com.au/html/ education/Water_Cycle/index.cfm
	Comprehensive educational website with many aspects of water supply, use, quality and waste.	City West Water www.citywestwater.com.au

Activities

Band	Activity	Contact
Primary Years	Follow the school education link to upper primary. Activities include: Facts for you. What is water made of? We are all watery. Watery me. Water diary. Waste and waste water systems. How water gets to your place and how tap water comes out quickly.	City West Water www.citywestwater.com.au
	Extensive resources for Primary Schools in water education, including water supply activities.	Gould League www.gould.edu.au
	Water cycle management. Simple illustrations and explanations about how water is managed.	Shoalhaven City Council www.shoalwater.nsw.gov.au/ 4education/Default.htm
	Fun interactive website for kids to play and learn about water.	Gippsland Water www.gippswater.com.au/ education/student.asp
	Many water companies have websites with numerous facts, figures and information about local areas. Investigate your local water company.
Middle Years	'Every Drop Counts'. Extensive resources for Secondary Schools in water education, including developing plans for dealing with water issues in the school.	Gould League www.gould.edu.au
	Follow the school education link to 'Activities for years 7 to 10'. A range of activities for middle years on water use and conservation. City West Water - Facts for you. The world's water quality and pollution. A cool guide to saving water. The amazing uses of water. Water conservation survey, 'Water diary - the water I used today'. Where does our water come from and how pure is it? Where does it go to be treated?	City West Water www.citywestwater.com.au
	'The Waterworks Adventure'. Challenging interactive activity involving the planning of water supply, stormwater and sewerage system for a town. Requires a brief registration process.	Melbourne Water www.melbournewater.com.au/ ww/wwa/index.cfm

Who Can Help?

Organisation	Who Can Help?
SA Water	SA Water
United Water	www.uwi.com.au

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