State and territory summaries

The key points from the state and territory summaries provided in the Water Availability Regional Water Balances report, which is available on the Publications page, are given below.

Australian Capital Territory

  • Water use is almost wholly from surface water with little information available on the groundwater systems
  • In 2004-05 the environment’s share of the total flow in the Australian Capital Territory was 60%
  • There was no information available on farms dams, or self extracted groundwater, or groundwater / surface water interactions.

New South Wales

  • In northern NSW above average rainfall (approximately 120% of average rainfall) occurred within the Gwydir, Namoi and Hunter regulated water management areas. The remaining areas experienced average rainfall for 2004-05.
  • The Sydney water supply area had a significant decrease in storage of 239 GL over the 2004-05 year.
  • The Gwydir and Murrumbidgee regulated water management areas experienced increases in surface water storage levels whilst all other catchments showed a decrease in volume.
  • Most of the water balances were data rich and the issue in assessing them was use of the best available data and information sources from models and other analyses. Any small discrepancies were assigned to a particular component of the water balance and hence these water balances have no unaccounted for inflows or outflows and an error term of 0%. However, this way of assigning the unknown flows to water balance items can be misleading with regard to the accuracy of the water balance.
  • The water balances have been done for regulated areas only (excepting Richmond and Sydney) which may misrepresent the true level of data availability and status of water resources in those catchments.

Northern Territory

  • Rainfall was much lower than average for 2004-05 with no rainfall experienced in some of the central and southern areas.
  • There was significant mining of the groundwater resource in the Mereenie Sandstone-Alice Springs Water Control District in 2004-05. This practice is deliberate and in accordance with the management plan for the area.
  • Water use is predominantly from groundwater due to the absence of surface water in most areas.
  • Most of the information used comes from the AWR 2000 assessment and few areas had more recent data available for the water balances.
  • Data and information availability was severely limited and stakeholders indicated that the water balances were of limited value because of this reason.

Queensland

  • Rainfall conditions in 2004-05 were below long term averages in most areas, around the 70-75% of average annual rainfall.
  • Most water balance areas rely on surface water with supplementary water sourced from groundwater in some catchments.
  • Data and information availability was variable depending on the water balance area. In some cases this was due to lack of resources and time to collate the available data from models and other assessments within the time frame provided to undertake the water balances.
  • There is little information on farm dam storages or flood harvesting for all areas, and this component of the water balance is expected to be considerable.
  • The Brisbane water balance was complex and difficult to compile due to the number of organisations that had to be consulted for water supply data (more than 21 councils and other organisations). Future assessments will have to ensure that all appropriate organisations are made aware of the assessment in order to obtain the data sets within the time frame available.

South Australia

  • Rainfall and streamflows were close to long term averages for the 2004-05 period.
  • On average Adelaide receives approximately 110 GL/year transferred from the Murray River for water supply.
  • Despite groundwater being a major component of the water supply, there is little information available on many of the water balance components relating to groundwater, such as evapotranspiration, groundwater / surface water interaction volumes, and groundwater use.
  • Stakeholders indicated that the water balances were more of an accounting exercise and of little value for on-ground management of the resource.

Tasmania

  • Water supply is dominated by surface water with more than 14% of Australia’s runoff occurring in Tasmania and little use of groundwater. For this reason, there is little information on groundwater in the state.
  • Information on farm dams and dam capacities is not well known in many areas.
  • Water usage information is not available in many areas and only entitlement or allocation volumes were available from which to estimate the actual usage.

Victoria

  • Rainfall conditions were close to average for 2004-05, however streamflows were well below long term averages.
  • Surface water is the dominant water source in the state with groundwater used extensively for stock and domestic purposes and town water supplies in the western portion of the state.
  • Most of the data for the water balances was sourced from the State Water Report 2004-05 (DSE, 2005). Some additional information for the Melbourne water balance was compiled from other authorities on drainage and rainwater tank volumes.
  • Groundwater information is collated for the groundwater management areas, however, these areas only cover a small portion of the state and hence information was not available for groundwater / surface water interactions, groundwater evapotranspiration, or groundwater extraction volumes for many of the water balances.

Western Australia

  • Rainfall in south western regions of the state where most of the water balance areas were compiled was slightly higher than average for 2004-05. In the long term, rainfall has decreased significantly since the 1970s for this region with greatly reduced runoff and recharge in all areas.
  • There is a high reliance on groundwater for both domestic and town water supplies with Perth heavily reliant on groundwater and surface water for its supply. For this reason there are highly reliable data sets available for both groundwater and surface water for most of the water balance areas.
  • A desalinisation plant was commissioned in November 2006 to supply an additional 130 ML/day to Perth.
  • A comparison of the Water 2010 datasets for the water balance areas and those provided by the Water Corporation of WA has indicated that the recharge estimates used by the Department of Water are higher than the Water 2010 estimates (possibly due to inclusion of ET losses as well), whilst the runoff estimates are much lower than the Water 2010 estimates.

Related links

States and territories are discussed in more detail in the following sections:

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Last Updated 30/05/2007