Physical information for improved management of land and water salinity : needs and status in the river murray basin

Abstract

In physical terms, the environmental problems of the River Murray Basin relate to the salting of land and water resources through natural processes, land clearing, irrigation and river structures. Land clearing and irrigation have caused the rise of saline groundwater throughout extensive areas within the Basin. In turn, these high watertables have increased the rate of salting of lands and waterways. For example, Peck et al (1983) estimate that 123,000ha of irrigated land are salt affected and that half a million hectares have watertables less than two metres below the surface. The likelihood of further salting is very high wherever watertables are not controlled. The economic and social effects of salinity include damage costs to agricultural and urban enterprises; revenue appropriations from taxpayers for the cost of salinity abatement schemes, monitoring, research and investigation activities; and threats to the social structure of many rural communities. From a political perspective, the salinity problems of the basin present a dilemma. Although governments want prompt and cost- effective action on salinity problems, actions of this nature are often unavailable owing to limited hydrogeological data, inadequate understanding of the physical systems and poor knowledge of ramifications on the associated economic and social systems.