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Key messages

  • In SA, we use about 75% of our fresh water for agriculture (860,000 ML), with 50% of that coming from groundwater, 27% from rivers, creeks and lakes, 14% from irrigation channels or pipelines, 5% from reticulated supply and the remainder from dams, tanks and recycled water.
  • We expect flow rates of our streams and the amounts of groundwater to reduce due to projected long-term reductions in rainfall.
  • Most inland waters are subject to nutrient enrichment (largely from agriculture and urban land uses) and inputs of fine sediment from erosion, and have narrow and weedy riparian zones that are often grazed by sheep and cattle.
  • Rainfall and intact native vegetation are positively correlated with the condition of our aquatic ecosystems and their locations.
  • The efficiency with which we use water markedly improved during the Millennium Drought, and has been maintained since.
  • South Australia has been addressing its limited water availability through more efficient water use, diversification of water supplies and management of water quality.
  • Wetland cover has declined in the 3 high-rainfall regions (South East, Adelaide and Mount Lofty Ranges, and Kangaroo Island) due to declining rainfall and intensified land and water use.
  • The condition of aquatic ecosystems is fair and improving, with 20% of ecosystems rated as 'good' to 'very good', 39% rated 'fair' and 41% rated 'poor' to 'very poor'. The proportion of sites rated 'poor' to 'very poor' is highest in the Eyre Peninsula and South East regions.
  • Steam flows are declining over most of SA.
  • Quality and quantity of groundwater is generally stable, with overuse in limited areas.
  • Populations of aquatic plants and animals that are threatened is increasing (getting worse).
  • Invasive fish have increased in abundance and distribution across SA since 2013. There is insufficient information to determine a trend in new incursions of invasive aquatic plants and animals.
  • 79% (30 of 38) of SA’s managed water resources have water allocation plans in place.

River Murray

  • The Murray–Darling Basin Plan is helping to improve the health of the River Murray in
    South Australia, but it is too early to assess the contribution of the plan to the overall
    health of the Murray.
  • Flows of 2016–17 were in the top 25% of the last 40 years and helped maintain healthy salinity levels.
  • The Murray Mouth is open on more days, but remains reliant on dredging.
  • The condition of River Red Gum and Black Box is stable, but River Cooba is declining.
  • The condition of River Murray high-value wetlands is poor, but improving in the Lower Lakes, Coorong and Murray Mouth region.
  • The condition of Coorong and Lower Lakes vegetation is poor and the overall trend is stable.

Figure 31 shows key pressures placed on the inland waters of South Australia, as well as an assessment of ecological condition from upstream to downstream.

soer2018_InlandWaters_infographic1Figure 31: Pressures on inland waters and assessment of health in South Australia