DES Seminar by Sarah Taylor (PhD Candidate)

28 November 2014

The Hydrogeochemistry of shallow saline groundwater in Western Sydney.

Salinity of some shallow groundwater and surface water features in Western Sydney has been observed for more than 200 years, however the cause of this salinity has never been thoroughly investigated. Many small scale hydrogeological studies of shallow groundwater have been undertaken in the region, but these have been fragmented in space and time, with a focus on determining the potential salinity risk at the site of a proposed development, and not on determining the cause and mechanisms of salinisation.

In this study, a comprehensive groundwater sampling program was undertaken in four locations across Western Sydney in conjunction with analysis of historical data, in order to identify the extent of groundwater salinity, to determine the geochemical character of the groundwater and to identify the source of salinity.

Groundwater salinity was found to be a region-wide issue. Shallow groundwater was almost always Na-Cl type and has a meteoric signature, excluding the possibility of connate or formation water being the salt source. Concentration of salts from rainfall occurs through evaporation and transpiration which is enhanced by the clay soils and underlying shale slowing water movement.

The knowledge gained from this study will be used to develop a conceptual model of shallow groundwater processes in Western Sydney. Successful salinity management requires detailed information on local causes and mechanisms of salinisation, which are currently unavailable for Western Sydney, but urgently needed as significant growth is planned for the region over the next 20-30 years.

All welcome to attend.

Time: 4PM

Location: Room 422, Biomedical Building, C81, ATP

Contact: A/Prof Willem Vervoort

Phone: 02 8627 1054

Email: 4f5b2e0934347e1a0b031e3544201b02262c080d370b7f074b364a2f02