Groundwater Flow Systems

Back to Salinity Management | Groundwater Flow Sytems Report

Groundwater Flow Systems (GFS) have been developed in the National Land and Water Audit (NLWRA) as a framework for dryland salinity management in Australia. They "characterise similar landscapes in which similar groundwater processes contribute to similar salinity issues, and where similar salinity management options apply" (Coram, et al., 2001).

In Australia, twelve GFS have been identified on the basis of nationally distinctive geological and geomorphological character. In the Audit, GFS are characterised by their hydrological responses and flow paths into local, intermediate and regional systems. This terminology should not be confused with that used in classic groundwater textbooks for the nested flow systems in groundwater basins, rather, in the terminology used by the Audit local, intermediate and regional GFS are described by their response rate to hydrological change caused by alteration to the natural environment. The underlying assumption is that salinity is caused by increased recharge leading to rising groundwater tables, which have resulted from changes in land management over the past 200 years.

Eighteen Groundwater Flow Systems have been delineated in the Port Phillip and Westernport Catchment management region - based on the NLWRA model. Of these, 15 are predominantly local groundwater flow systems, 2 are predominantly intermediate, and one is predominantly a regional flow system. While GFS provide a useful tool in the understanding of salinity processes, confidence in management options for the protection of different classes of assets (e.g. water quality, environmental, agricultural, urban and engineering infrastructure, and cultural and heritage) requires confidence in the conceptual model of how the groundwater and salinity processes operate. To date there has been very little scientific validation of the flow systems or salinity process models in the Port Phillip and Westernport region. However, the delineation of groundwater flow systems provides the most current and appropriate framework for the selection of salinity management options, as well as the opportunity to assess the knowledge gaps in the hydrogeology of the region.