||Technology in Australia 1788-1988
Table of Contents
II Early European Settlements
III Assessment Of Available Water Resources
IV Water Supplies For Goldmining Development
V Irrigation Development
VI Farm And Stock Water Supplies
VII Urban Water Supplies
VIII Wastewater Management And Treatment
IX Water Quality Management
i Eppalock reservoir catchment project
ii Ord River catchment regeneration project
iii Salinity reduction
X Limnological And Water Quality Research
XI New Techniques In Water Resource Planning And Management
XIV List Of Abbreviations
XVI Plantations-high Productivity Resources
Salinity reductionThe salinity of many rivers and aquifers in Australia has increased significantly during this century, posing a serious threat to water users, particularly to irrigators. The principal causes are change in land use, diversion of water from rivers for consumptive use, the construction of reservoirs and the disposal of saline liquid wastes in basins or wells. Western Australia has given particular attention to the land use aspect of this problem, by introducing legislation to control land use in critical areas, e.g., by prohibiting clearing of natural vegetation, and by withholding releases of Crown land.
Reduction of salinity in rivers and streams has been tackled by two main methods -management of reservoirs and management of flows in, and the inflows to rivers. In the first category, salinity in a reservoir on the Collie River in Western Australia is controlled by releasing through scouring off-takes the more dense saline water flowing beneath less saline water in the reservoir, before vertical mixing occurs. The Menindee Lakes Scheme in New South Wales is managed to minimise evaporation loss and so reduce salinity increase by keeping the surface area of the lakes at a minimum during the periods of high evaporation loss.
In the second category, the largest and most important example of stream management to reduce salinity is in the operation of the River Murray system in three States. The methods used include upstream reservoir releases, the interception of saline drainage waters and the diversion of saline tributaries, with disposal to evaporation basins. The design of interception and diversion works and the associated investigation of possible adverse effects on adjoining land and groundwater are complex and necessitate a comprehensive technological approach through a wide range of disciplines. The subsequent flow management procedures are equally complex.
Groundwater salinity may increase after a period of pumping due to leakage from a hydraulically connected saline aquifer, or the movement of a fresh-salt water interface within the pumped aquifer. Sea-water intrusion has been controlled by artificial recharge, control of pumping and the importation of surface water to supplement or replace local groundwater.
Salinity of surface water and groundwater remains a serious problem in many parts of Australia, and increasing technological effort and innovation will be required to effectively control and reduce it.
Organisations in Australian Science at Work - Menindee Lakes Scheme, N.S.W.; Ord River Catchment Regeneration Project, W.A.
© 1988 Print Edition pages 183 - 184, Online Edition 2000
Published by Australian Science and Technology Heritage Centre, using the Web Academic Resource Publisher