Murray Darling Case Study of Unsustainable Water Use


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Murray Darling Case Study of Unsustainable Water Use

  1. 1. The Murray-Darling Basin <ul><li>A case study of unsustainable water use </li></ul>
  2. 2. Location <ul><li>The basin takes its name from two dominant rivers, the Murray and the Darling, </li></ul><ul><li>The rivers have a combined length of 3,780 kilometres. </li></ul><ul><li>The basin extends over one million square kilometers (about the size of France and Spain combined) , which is about one -seventh of the land area of Australia </li></ul>
  3. 3. Land use in the Murray-Darling Basin Dryland crops 10.5% Irrigated Crops 1.8% Dryland Pasture 66.7% Native Vegetation 20.3% Plantation Forests 0.4% Urban Areas 0.3%
  4. 4. Money and the Murray <ul><li>Gross product of over$23 billion. </li></ul><ul><li>Around 40% of Australian agricultural production originates from the Murray-Darling Basin. </li></ul>
  5. 5. Agriculture in the Murray-Darling Basin <ul><li>Covers nearly 80 percent of the Basin. </li></ul><ul><li>Predominantly dryland sheep and cattle production. </li></ul><ul><li>Dairying is the main irrigated livestock industry. </li></ul><ul><li>Important cropping activities include cereals (particularly wheat, barley and rice), oilseed, cotton, and horticulture (particularly citrus, stone and pome fruits, grapes and vegetables). </li></ul>
  6. 6. Urbanisation <ul><li>Many towns in the basin: </li></ul><ul><li>Toowoomba, Tamworth, Moree, Orange, Dubbo, Wagga Wagga, Griffith, Albury-Wodonga, Shepparton, Bendigo, Horsham, Mildura and Renmark </li></ul>
  7. 7. Eutrophication <ul><li>Eutrophication Animation </li></ul>
  8. 8. Land Clearing <ul><li>Remnant native vegetation covers around 20% of the Basin area. </li></ul><ul><li>Agricultural and urban development has involved extensive clearing of native vegetation </li></ul>
  9. 9. Irrigation <ul><li>The Murray-Darling Basin uses 60% of all irrigation water in the country. </li></ul><ul><li>The food growing area around the river is often referred to as Australia’s ‘food basket’. </li></ul>
  10. 10. Salinity <ul><li>Salinity is the dominant issue in the south west, south east, and in the Murray-Darling Basin. </li></ul><ul><li>Some intense water-logging and salinity has occurred associated with irrigation, but the irrigation areas are small. </li></ul><ul><li>Of more widespread significance is dryland salinity </li></ul>
  11. 11. How salinity occurs <ul><li>Salinity Animation </li></ul><ul><li>Salinity increases as you go downstream, as after each rain or irrigation event salts are washed into the waterway. </li></ul><ul><li>Saline water levels in the Murray are increasing as water levels drop, as saline water is not frequently flushed out to sea. </li></ul><ul><li>Treatment of saline water is costly for human and agricultural use. </li></ul>
  12. 12. Low water flows <ul><li>Total flow at the Murray mouth has been reduced by 61% </li></ul><ul><li>The river now ceases to flow through the mouth 40% of the time compared to 1% of the time in the absence of water resource development. </li></ul>
  13. 13. Wetlands Disturbed <ul><li>Disturbance of wetlands in the Murray-Darling Basin has occurred through modification of the river(s) including construction of dams and the diversion of water for irrigation, stock and domestic uses. </li></ul>
  14. 14. Impact on Lower Lakes <ul><li>The Coorong is recognised as one of the top six water bird sites in Australia and is listed as a wetland of international significance under the Convention of Wetlands (Ramsar, Iran, 1971) </li></ul>
  15. 15. Political Issues <ul><li>State sovereignty means that the water-sharing situation is not unlike an international basin. Each State arguing over water allocations. </li></ul><ul><li>New national plan for water security. Taking too long for States to agree that damage may be irreparable. </li></ul>
  16. 16. Climate Change Uncertainty <ul><li>The impacts of climate change by 2030 are uncertain. </li></ul><ul><li>Surface water availability across the entire Murray-Darling Basin is more likely to decline than to increase. </li></ul><ul><li>The southern areas most likely affected. </li></ul>
  17. 17. Unsustainable Use Source: CSIRO (2008) <ul><li>If we take the median value of water availability 20,936 GL/Year and the maximum water availability in a given year 26,047. </li></ul><ul><li>If an average year was followed by a maximum surplus year, the sustainable yield would be 5,111 GL for the following year. </li></ul><ul><li>Median predicted use of surface water in the basin in 2030 is 10,876 GL/Year. </li></ul><ul><li>This means that use of water from the Murray is double what is sustainable after a good year of rain. </li></ul>
  18. 18. The Future? Get involved: