Indicators of Catchment Condition in the Intensive Land Use Zone of Australia – Catchment Condition Index

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

The overall Index of Catchment Condition was based on a combination of the 14 indicators used for the Sub-index assessments.

Method: Indicators equal area stretched into 5 classes are added and the resultant grid resliced into 5 equal interval classes.

Datasets included in this assessment were: sedl, pest, indu, nutr, impn, st50, sdeg, eros, frag, nati, prot, rden, fera, weed.

There are large, coherent areas with relatively poor condition in the wheat and sheep zone of Western Australia, through central and western Victoria and west Gippsland, and onto the western slopes and plains of New South Wales.

In Western Australia the poorest catchments are mainly in the mid to upper slopes of the major catchments. This heterogeneity is masked at the AWRC basin scale.

Most of sub-catchments in the intensive landuse zone in West Australia fall into the category next to the poorest category.

In South Australia none of the sub-catchments fall into the poorest category.

The poorest areas are located in the Yorke Peninsula and in the catchments around Adelaide and in the south-east corner of South Australia.

In the eastern states the catchments in poorer condition are now more confined and disjunct, they tend to be located in the mid-slopes of the major east-west trending catchments in New South Wales and south-central Victoria.

In the coastal catchments in New South Wales, the catchments in the corridor between Sydney and Goulburn and the Hunter River catchment are in the poorest category.

In Queensland, the catchments in poorer condition include the upper reaches of the Condamine and Mackenzie River systems, and the more intensively developed large river basins in central Queensland to south-east Queensland (Fitzroy coastal, Burnett, Mary, Maroochy, Pine and Brisbane) and smaller coastal basins with developed coastal plains.

Similar to the 5 km resolution, catchments in relatively good condition again lie within the less intensively used parts of the assessment area (Northern Territory, Cape York and inland New South Wales and South Australia).

However, in the higher rainfall zone the influence of conserved lands is less and as a consequence good catchment condition areas are much more restricted.

Tasmania generally and in particular Southwest Tasmania, north-eastern Victoria, the Blue Mountains National Park, parts of the Upper Clarence Basin in New South Wales and the south-west of Western Australia are of relatively better condition.

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.