Scientists test ‘fractured rock groundwater systems’ for South West farmers to access

Unconventional water sources for farmers to access in the dry season are being investigated with Manjimup and Kojonup trials under way. The trials are part of a project called WaterSmart farms with 63 farmer partners exploring alternative desalination technologies and ways to manage wastewater. Senior principal research scientist for the project Richard George said it evolved out of the most recent dry seasons. He said the project seeks to support farmers with enough water on their land instead of relying on dams, springs and traditional water supplies. While he said traditional methods worked in most years, farmers faced challenges when run-off rain was low. The project looks at alternate water supplies from deep, fractured rock groundwater systems. At the beginning of the project, the research revealed a “brand new water resource” in the ground due to clearing in the Wheatbelt. “The outcome of all water tables that have been rising over the last 50 years, 100 years since clearing, is that we’ve now got saline groundwater coming out of saline patches, coming out of saline creek lines,” Dr George said. “One of the ways of dealing with that is to go and get that water before it goes into the ground, or as it’s going into the ground, when the water is actually of a better quality. Instead of the water coming out in a creek, Mr George said the research showed it would be beneficial to “intercept” it. He said the project was testing if farmers can “pull” water yields ranging from 50,000 to more than 300,000 litres per day. “We’ve realised that some of this groundwater is sufficient quality and quantity to not replace your dams, but to act as a very good second supply of water on farms,” Dr George said. The project was initially prompted from the dry years from 2018 to 2020, he said. From 2020, the project focused on locating groundwater in fractures in the Great Southern and western Wheatbelt. However, in 2024, the drying climate became an acute issue in the Blackwood area. “We decided to work with Curtin University and the Department of Energy, Mines, Industry Regulation and Safety to locate groundwater in the top 100m of the Wheatbelt, down in the fracture,” Dr George said. “We’ve chosen 20 sites to drill out from Merredin to Manjimup, and we did that over two seasons and drilled 20 holes.” He said the “unconventional” way of looking for water contrasted traditional forms, which are seeps occurring on the sides of hills or water in the top 20m or 30m of clay soils. In the higher rainfall areas, from Kojonup to Manjimup, nearly all of the drill holes produced water that was suitable for livestock. “But we realised broader across the whole of the project, that not everywhere that you find water, or that you’ve previously found water, is going to be of the right quality,” Dr George said, Setting up four desalination units to trial and tracking 31 farmer-installed units across the Wheatbelt and Great Southern forms the second part of the project. The third part of the project will be to track and manage “rejected water” to prevent consequences downstream. Dr George said the first part of the project would conclude in June before the research was written up.