Desalination in Rural Towns - Liquid Assets
Background
Saline groundwater is a problem in many rural towns in Western Australian. As the groundwater table rises, due to changes in the vegetation or human usage of water altering the water balance, ecosystems become threatened and damage to buildings, roads and other infrastructure (such as water and wastewater pipes) occurs.
In Katanning, for example, the Department of Agriculture estimates salinity damage will cost almost $7 million over the next 30 years. Roads in and out of the town require repairs and houses are being elevated for protection from salty water percolating up through the soil.
Some 38 towns across the State are significantly affected by salinity with an estimated damage bill of up to $55 million over the next 30 years.
A proactive approach has been taken by the local Shires and several Government organisations to overcome this problem. The Shire Councils have teamed with CSIRO and the Department of Agriculture to develop water management plans to seek to reverse and eventually eliminate the water-logging and salinity problems.
The Rural Towns – Liquid Assets project commenced in 2004 to deliver Water Management Plans to 16 priority towns in the wheatbelt area.
The project’s major objective was to protect town-site infrastructure from salinity, water-logging and flooding by employing innovative solutions to groundwater abstraction, surface water control, treatment and disposal. It was also intended to utilise excess or 'problem' water by turning it into a resource from which economic and social benefits may be obtained.
Specific objectives were to:
- protect town-site infrastructure from salinity;
- produce a model for integrated town water management;
- develop alternative new supplies plus recycled water schemes;
- reduce reliance on scheme water in towns;
- foster high value industries using new water supplies;
- protect remaining biodiversity areas in or adjacent to towns; and
- promote local ownership of water resource management.
From the Water Corporation’s perspective, the impact of this initiative is that salty groundwater in these towns could be treated to drinking water standard as an alternative water source for the town or local industry supplies. Some of these towns are currently supplied via the Goldfields & Agricultural Water Supply (GAWS) scheme, such as, Merredin, Wongan Hills, Dowerin and York. The potential impact of the loss of (part) supply in these towns would have a minimal impact on the overall supply via the GAWS.
Current Situation
Work is progressing in all 16 local government areas. Work in some towns, such as Merredin, is nearing completion. The focus of the project has changed from predominantly addressing rising saline groundwater to other management activities such as surface water catchment management and drainage management. Flooding or water-logging of the ground from these activities is major issue. There is now an added emphasis on water use efficiency within the towns.
The project is mainly focussed on providing non-drinking water supplies for rural towns to water ovals and crops.
Sustainability Considerations
Economic | Social and Cultural | Environmental |
| Reduces costs of damaged infrastructure caused by groundwater salinity. | Reduces damage to buildings and infrastructure. | Improves catchment management. |
| Minimises costs to the community for oval watering and other external uses. | Promotes water use efficiency. | Promotes water use efficiency. |
| Collaboratively funded. | Provides fit for purpose water source for town ovals and public open space. | Reduces flooding in towns. |
The Future
This project will continue into the foreseeable future. The Department of Agriculture and CSIRO will continue to work with the Shire Councils to develop water management practices and alternative non-potable water sources.
Although impact on future IWSS water grid demand is minimal these initiatives will have a positive impact on local scheme water consumption.