| |
CRC PUBLICATIONS |
Causes, Effects, Remediation and Measurement of Land and River Salinity in Australia
Mark Walker
Publication Type:
Technical Report
This is a publication of the initial CRC for Catchment Hydrology
CRC Program:
Salinity (Previous CRC)
|
Publication Keywords:
Salinity
Remediation
Salinity Transport
Salts
Water Movements
Groundwater
Recharge
Discharge
Land Clearing
Irrigation
Soil (Characteristics of)
Determination
Remote Sensing
|
Abstract / Summary:
Causes, Effects, Remediation and Measurement of Land and River Salinity in Australia - A Report as part of Project A1: Runoff and Solute Processes in High Water Table Areas; Measurement, Modelling and Management
ABSTRACT
The salinisation of soil and water is a severe problem in many arid, semi-arid and temperate parts of Australia. Substantial areas of low lying prime agricultural land are affected by saline groundwater discharge and shallow watertables. This is especially the case in the irrigation districts of the Murray-Darling basin, and Western Australia. Saline streams and rivers are also a problem in these areas. This paper reviews the processes leading to the salinisation of land and waterways, effects of salinity, remediation and management techniques.
Soil salinity is caused by the domination of salt accumulation processes over leaching processes within the near surface layers of the regolith. Salt in soil comes from a variety of sources: it is released from soil and bedrock by chemical weathering; from previously marine sedimentary basins; it is deposited on the soil surface with rainfall and as dry fallout; and may be added with low quality irrigation water. Salt accumulates through evapotranspiration and the discharge of local or regional saline groundwater. In many farming areas, human activity has changed the salt balance, creating new salt movement pathways, enhancing existing salt movement and facilitating salt discharge. In particular, clearing of forested land for pasture or shallow rooting crops and the application of irrigation water have dramatically altered the water balance of both local and regional groundwater systems. The result has been enhanced recharge and subsequent watertable rise or discharge in low lying areas, at the break of slope or where changes in the permeability of soil, bedrock or sediments cause a build up of groundwater.
Excess salt affects plants and animals by increasing water demand and leading to poor growth, and death under severe conditions. Soil salinity often causes the replacement of adsorbed calcium and magnesium with sodium which increases dispersibility and the shrink swell capacity of the soil.
Salinity remediation techniques to reduce saline seepage and salt transport to rivers have focussed on reforestation, afforestation of recharge and discharge areas, drainage, interception, and irrigation management. Total Catchment Management may be the most fruitful method of approaching salinity problems where there are conflicting land use interests and landowners with different salinity problems.
Salinity research is focussing on saline area detection and the detection of groundwater movements. Novel integrated approaches using GIS and remote sensing may prove to be useful in salinity detection and management.
 |
1 Download(s) |
|
|
|
|
|
|
|
|
Centre Office:
CRC for Catchment Hydrology
Dept of Civil Engineering
Building 60
Monash University Vic 3800
Tel: +61 3 9905 2704
Fax: +61 3 9905 5033
|
|
|
