Indicator: IW-20 Exceedance of salinity water quality triggers

Data

Exceedance of water quality guidelines for salinity
	Major exceedances	Significant exceedances	Number of basins assessed
NSW	2	5	16
Vic	8	6	21
Qld	2	4	16
WA	11	2	17
SA	1	2	4
ACT	0	5	5
Total	24	18	74

Adapted from Source: National Land and Water Resources Audit 2001, Australian Water Resources Assessment 2000. Surface water and groundwater - availability and quality, Land and Water, Canberra, viewed 5 Dec 2005, http://audit.ea.gov.au/ANRA/
water/docs/national/Water_Quality.html.

Australia’s climate and ancient weathered landscape result in naturally high stores of salt within a range of soil types. Consequently, there are relatively high ‘natural’ salinity levels in Australian surface waters. This is compounded by the increasing extent of groundwater rise from dryland and irrigation salinity processes.

Salinity is an issue in much of temperate southern Australia and affects basins in the majority of the South-West Coast, the southern South-East Coast and southern Murray-Darling Drainage Divisions. Four basins in western New South Wales within the Murray-Darling Drainage Division, one east coast basin in the South Coast Drainage Division (Hawkesbury) and three basins in the South Australian Gulf also recorded major and significant salinity exceedances.

Available data indicated both increasing and decreasing trends, e.g. two affected basins in the South-East Drainage Division showed increasing trends while another two affected basins showed decreasing trends. Within the Murray-Darling Drainage Division at least four affected basins had decreasing trends while three affected basins had increasing trends.

Source: National Land and Water Resources Audit 2001, Australian Water Resources Assessment 2000. Surface water and groundwater - availability and quality, Land and Water, Canberra, viewed 5 Dec 2005, http://audit.ea.gov.au/ANRA
/water/docs/national/Water_Quality.html.

The Effects of Salinity Management in the Murray-Darling Basin: Average Salinity Levels in the River Murray at Morgan (South Australia) 1980-2003

Source: Murray-Darling Basin Commission 2003, Murray-Darling Basin Commission - Salinity update 2003: Salinity levels in the Murray River, Murray-Darling Basin Commission, Canberra, viewed 14 Oct 2005, http://www.mdbc.gov.au/
salinity/mdbc_salinity_update_2003.

The Effects of Salinity Management in the Murray-Darling Basin: Average Salinity Levels in the River Murray at Morgan (South Australia) 2002-2003

Salinity mitigation schemes developed under the MDB Salinity and Drainage Strategy have successfully halted the rising salinity trend at Morgan.

There are increasing trends in stream salinity from upland catchments, particularly in NSW. Clearing has probably mobilised stored salt from these areas.

The northern areas are showing little evidence of salt export to streams although there are some early warning signs.

Over the next 50-100 years, long-term groundwater rises as already seen in the Mallee and the non-irrigated areas of the Riverine Plains will override the benefits gained through the existing measures, developed under the Salinity and Drainage Strategy.

Source: Chartres, C, Stauffacher, M, Walker, G and Hatton, T 2003, Is the River Murray water quality deteriorating? A salinity perspective, CSIRO Land and Water, Canberra.

What the data mean

Salinity is a major water quality issue in 24 (32%) of assessed basins, particularly in the temperate South-West Coast, South-East Coast and southern Murray-Darling drainage divisions.

Salinity mitigation schemes developed under the MDB Salinity and Drainage Strategy have successfully halted the rising salinity trend at Morgan.

Data Limitations

NLWRA data have not been updated since its report was published in 2001.

Issues for which this is an indicator and why

Inland Waters - Habitat scale influences - Water Quality (for surface and groundwater) - Salinity

Number of exceedences of water quality triggers for salinity is a direct measure of this pressure.

Other indicators for this issue:

CO-68 Examples of sea surge and seawater intrusion events

Further Information

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State of the Environment

2006