Increasing groundwater salinity in the northern wheatbelt

Every farmer in western Australia\u27s northern wheatbelt will know of a groundwater supply, be it bore, well or soak. that has become increasingly saline. The groundwater may have become more saline over a period of 15 years or more, or have been noticed only recently. Inevitably, the bore will lie within an area cleared for agriculture. This increase in groundwater salinity may be associated with soil salinisation. Although researchers have some understanding of the processes causing salinisation of groundwater in the wheatbelt and the extent of the problem, little is known about the rates of salinisation and groundwater rise. A preliminary survey by the Department of Agriculture showed that the average bore water salinity in the northern wheatbelt had increased during the eight-year period. In 1983, the Geological Survey and the Department started a more detailed joint project to moniter the changes in groundwater levels and salinities in the Winchester Catchment in the northern wheatbelt. The aim is to measure trends in groundwater salinity and to investigate the causes of salinity increases. These analyses could help to identify suseptible areas elsewhere. This article discusses the cause of saline groundwater, the purpose of the Winchester Catchment study and some early results