Sustainable Water Supply

1. Sustainable Water Supply • How do human activities influence water supply and demand?

2. The Murray-Darling River Basin - Australia Water supply and demand – competing uses.

4. Where is it? • The Murray-Darling Basin is 3,375 km long, drains one-seventh of the Australian land mass, and is currently by far the most significant agricultural area in Australia. The name of the basin is derived from its two major rivers, the Murray River towards the mouth in the SW and the Darling River to the source in the NE .

5. Geography of the area • Most of the 1,061,469 km² basin is flat, low-lying and far inland, and receives little rainfall. The many rivers it contains tend to be long and slow-flowing, and carry a volume of water that is large only by Australian standards. • The rivers have very low gradients over most of their length, which cause them to flow slowly as they meander across the vast inland plains.

6. Water Demands • It contains over 40% of all Australian farms, which produce wool, cotton, wheat, sheep, cattle, dairy produce, rice, oil-seed, wine, fruit and vegetables for both domestic and overseas markets. As Australia's most important agricultural region, the Basin produces one third of Australia's food supply and supports over a third of Australia's total gross value of agricultural production. • Three quarters of Australia's irrigated crops and pastures are grown in the Basin.

7. Water demands • The Murray-Darling Basin is also very important for rural communities and Australia's economy. Three million Australians inside and outside the Murray-Darling Basin are directly dependent on its water. About 85 per cent of all irrigation in Australia takes place in the Murray-Darling Basin, which supports an agricultural industry worth more than $9 billion per annum. • The long-term productivity and sustainability of the Murray-Darling Basin is, however, under threat from over-allocated water resources, salinity and climate change.

8. The national capital Canberra, is located in the Basin along with many of Australia's major inland urban centres. Over 2 million people live in the Basin.

9. Australia: Water hogs leave Darling high and dry downstream Thanks to the drought and too much water being taken upstream, a once great river has been reduced to use as a cricket pitch

10. The water crisis The Murray-Darling Basin has reached record-low levels. The main reason for this is that Australia is experiencing its worst drought in possibly a thousand years. According to the Bureau of Meteorology, drought is part and parcel of life in Australia, simply because of its geographical location. Nevertheless, with climate change threatening to make matters worse, finding a solution to the water crisis is becoming more urgent.

11. What are the demands? • Industrial and domestic useThe industrial and domestic needs for water have meant that regulation and control of the river’s natural flow has affected its wetlands fauna and flora. The use of locks and dams interrupts the geological course of the river, restricting water in some areas where it is urgently needed, while other areas receive more water than they normally would in a heavy rainfall season. This has affected the breeding cycles of animals and plants adding to a decrease in water quality.

12. The rise of salinity The river system already has serious problems with salinity. Agriculture is mostly to blame for this—land clearing increases the amount of naturally occurring salt rising to the river’s surface and irrigation uses groundwater with high saline levels. It is estimated that salinity costs the users of the Murray River $47 million each year. This is due to lower productivity; loss of recreation; and the impacts on biodiversity caused by poor water quality and shrinking floodplains and wetlands.

13. Chemical pollutionApart from pollution in the form of salt and clay particles, the water quality of the Murray-Darling Basin is threatened by sewage and storm-water pollution, and fertilizer and pesticide runoff. Pollution from irrigated dairy pastures has also produced faecal bacteria in the water. There has been a reduction in pollution over the last decade, however there are still concentrations of some chemicals.

14. Time for change • At the 3 July 2008 meeting of the Council of Australian Governments (COAG), the Prime Minister, Premiers of New South Wales, Victoria, South Australia and Queensland and the Chief Minister of the Australian Capital Territory signed an Intergovernmental Agreement on Murray-Darling Basin Reform.

15. 5 (a) (i) Use Resource 3a to describe factors that may have accounted for the lack of river flow through the mouth of the Murray River in 2002. (10)

18. Answers • Thirty major dams and over 4, 000 weirs clutter the Murray-Darling Basin's rivers. Placing too many structures across rivers causes changes to flow patterns, loss of beneficial flooding, erosion of river banks and also salinity problems.*a weir is a small dam generally under four metres in height. Weirs prevent or reduce the migration of native fish. • Population increase • Low lying relief • Increased diversions • Rainfall deficiency • Varied climatic conditions

20. 5 (a) (ii) Use Resource 3b to explain why Adelaide has a problem with the quality of drinking water extracted from the Murray River. (5)

21. 5 (b) Identify the main conflicts that have arisen through the increased demand for water in this drainage basin. Use Resource 3c. (10)

24. Answers • Irrigation (farmers, residents) - About 85 per cent of all irrigation in Australia . • Aborigines – Spiritual value destroyed. • Natural heritage – holds key to history of area, should be preserved. • Conservationists – massive environmental impacts. • North - South conflicts of use.

25. 5 (c) The use of water in the Murray-Darling Basin is no longer sustainable. Use Resources 3s, 3b and 3c to evaluate the importance of the different factors contributing to this problem (10)

26. Answers • Dams/weirs • Diversions • Lack of rain • Increased population • Lower flow • Many states in the basin • Low lying relief • Increasing demand for food = increased irrigation • Increasing population = further dmands • Environmental damage increasing. • Increasing salinity – water unusable. • Poor, variable and unreliable climate.

27. 5 (d) Resource 3d shows current methods of addressing the problems of sustainable water use. Assess their merits and limitations. Use all Resource 3 to help you answer. (15)