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Legislative Assembly for the ACT: 2002 Week 7 Hansard (5 June) . . Page.. 1960 ..

MS TUCKER (continuing):

The Murray-Darling Basin Commission lists a number of major land degradation problems in the Murray-Darling Basin because of human activity. They are: wind and water erosion; dryland and irrigation induced salinity; soil surface scalding; waterlogging; soil acidity, structure decline and fertility decline; vegetation decline and degradation, such as weed infestation and lack of tree regeneration, and loss of flora and fauna and hence biodiversity.

Most forms of land degradation contribute to the impairment of the basin's water resources. Over much of the basin the natural quality of the water-that is, what it might have been like prior to European settlement-is not high. This is due to the biophysical nature of the basin. Not only is it a naturally saline environment, but turbidity levels are naturally high. Unfortunately this quality has been significantly degraded by human activity since settlement.

The commission notes that there is a general decline in water quality with distance downstream, though this is by no means a simple relationship. The sources of pollution are many. There are the diffuse sources, in particular run-off from agricultural land. Not only does such run-off contain all kinds of substances, it is very difficult to control.

Then there are the point sources, sometimes difficult to control but much more readily identifiable. They include drainage from irrigation schemes, stormwater run-off from urban areas, effluent from urban sewerage treatment works, and from industries and intensive agricultural operations such as feedlots. The ACT is fortunate in that it is high up in the catchment, so we don't cop huge amounts of pollution flowing into the territory. But, of course, we are contributing to problems downstream.

The Murray-Darling Basin by its nature is a natural salt trap. The clearing of native vegetation and its replacement with annual crops and pastures, irrigated agriculture, town gardens and lawns has brought this vast salt store to the land surface and increased its seepage to river systems. Because of its pervasiveness in the landscape, salinity is more than just a threat to water quality. It also impacts on environmental values for rivers and wetlands. It causes damage on the land-to built infrastructure, agricultural production and the environment.

The salinity audit of the basin undertaken by the commission found that the average salinity of the lower River Murray will exceed the threshold for desirable drinking water quality in the next 50 to 100 years. At the downstream end of several tributary river valleys, rising salinity will be even greater, threatening consumptive use of water resources and in-stream environmental values within 20 years.

These issues need to be addressed at a national level, and I am disappointed by the lack of commitment shown by the current Liberal government to addressing what is really almost a national emergency. There is far too much short-sightedness and narrow self-interest being demonstrated by the state and federal governments on the management of water within the Murray-Darling Basin. At least this Assembly can ensure that the territory plays a positive role within the basin by managing its water on a sustainable basis.

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