Beyond hydrogeologic evidence : Challenging the current assumptions about salinity processes in the Corangamite region, Australia
- Authors: Dahlhaus, Peter , Cox, Jim , Simmons, Craig , Smitt, C. M.
- Date: 2008
- Type: Text , Journal article
- Relation: Hydrogeology Journal Vol. 16, no. 7 (2008), p. 1283-1298
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- Description: In keeping with the standard scientific methods, investigations of salinity processes focus on the collection and interpretation of contemporary scientific data. However, using multiple lines of evidence from non-hydrogeologic sources such as geomorphic, archaeological and historical records can substantially add value to the scientific investigations. By using such evidence, the validity of the assumptions about salinity processes in Australian landscapes is challenged, especially the assumption that the clearing of native vegetation has resulted in rising saline groundwater in all landscapes. In the Corangamite region of south-west Victoria, salinity has been an episodic feature of the landscapes throughout the Quaternary and was present at the time of the Aboriginal inhabitants and the first pastoral settlement by Europeans. Although surface-water salinity has increased in some waterways and the area of salinised land has expanded in some landscapes, there is no recorded evidence found which supports significant rises in groundwater following widespread land-use change. In many areas, salinity is an inherent component of the region's landscapes, and sustains world-class environmental assets that require appropriate salinity levels for their ecological health. Managing salinity requires understanding the specific salinity processes in each landscape. © Springer-Verlag 2008.
Salinity on the southeastern Dundas Tableland, Victoria
- Authors: Dahlhaus, Peter , MacEwan, Richard , Nathan, Erica , Morand, Vincent J
- Date: 2000
- Type: Journal article
- Relation: Australian Journal of Earth Sciences Vol. 47, no. 1 (2000), p. 3-11
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- Description: Historical evidence of early salinity, vegetation and landuse changes, and pedological studies have been used in formulating a new model for salinity processes acting on the Dundas Tableland in southwestern Victoria. Contrary to previous assumptions, salinity in this area was a feature of the pre-European landscape and was noted in the earliest surveys and journals. Analysis of historical records show an initial post-settlement increase in the tree numbers, followed by a rapid decline much later than previously assumed. Accumulation of salts in the regolith may be attributed to marine incursions during the Miocene and Pliocene, the extensive weathering to develop a deep regolith, and wind-blown and cyclic salt accumulation. A trend analysis of historical streamflow and bore hydrograph records does not indicate rising groundwater levels. The pedological features of duplex and sodic soil profiles support a history of prolonged seasonal waterlogging. A model with seasonal lateral flow of water through the upper regolith can better account for the spread of salinity than the rising groundwater hypothesis. By control of waterlogging, land managers could improve soil structure, enhance root growth and soil water use, as well as inhibit the spread of salinity.