Indicators of Catchment Condition in the Intensive Land Use Zone of Australia – Nutrient point source hazard

It should be noted that this data is now somwhat dated!

Nutrients can enter streams from point, diffuse from various extensive land- uses or natural sources. In this indicator only industrial point sources (mines, quarries and chemical plants) and intensive agricultural production and urban point sources (abattoirs, dairy, livestock production, sewerage) are considered. The Wild Rivers data set (Environment Australia) includes national data on point sources of pollution (1:250K).

This data set can be separated into industrial (mines, quarries, chemical) point sources and nutrient point sources (abattoirs, dairy, livestock production, sewage). These data were obtained from state and federal sources and much of the contaminated sites, chemical pollution and nutrient pollution data are far from comprehensive (i.e. available for NSW, Victoria and SA only).

Reliability of the available data is good, but the data set is incomplete. Only nutrient point source data is used in this indicator. The density of nutrient point sources is not an unequivocal indicator of excessive nutrient levels in nearby waterways, since diffuse agricultural sources and natural sources are not included. As for the industrial point sources, there is no distinction made between types of nutrients exported, discharge magnitude and frequency, existing environmental safe guards and proximity to stream network.

Interpretation is also confounded by the incompletedness of the data set. At best, this is an indicator of nutrient hazard. It has not been validated against the assessment question. The 500 and AWRC maps give a similar picture, with the major point sources located in the Murray-Darling Basin and central Victoria. The Bunyip, Moorabool, Kiewa and Ovens Rivers in Victoria, the Namoi River in NSW and the Torrens River in South Australia have a notably high nutrient point source hazard.

Data are available as:

• continental maps at 5km (0.05 deg) cell resolution for the ILZ;
• spatial averages over CRES defined catchments (CRES, 2000) in the ILZ;
• spatial averages over the AWRC river basins in the ILZ.

See further metadata for more detail.