One of Western Australia’s most experienced water experts says plans for a $70 million irrigation scheme in the state’s south-west will be an environmental and financial disaster.Key points:The irrigation project would dam a tributary of the Donnelly RiverOf the $70 million cost, taxpayers are providing $60 millionFarmers want the water to boost production in WA’s primary food bowlKim Taylor, a former director-general of the Department of Water who also ran the Office of the Environmental Protection Authority, said the case for the Southern Forests Irrigation Scheme was “critically flawed”.The scheme will involve damming a tributary of the Donnelly River near Manjimup, about 300km south of Perth, in a bid to increase food production in the region.It is being driven by a group of farmers from the area and is backed with $60 million of Federal and State Government money.The Department of Water and Environmental Regulation stood by its involvement with the project, which it argued could provide water in a sustainable way.Project modelling ‘overly optimistic’But Mr Taylor said the modelling that underpinned the proposal was based on overly optimistic assumptions about water availability and failed to take account of a drying climate properly.He said while rainfall totals had declined up to 15 per cent in the area compared with historical averages, the reduction in run-off had been much greater.Former Department of Water director-general Kim Taylor says the proposed dam is critically flawed(Supplied: Kim Taylor)And he said the trend would only become more pronounced in future as forecast rainfall totals dwindled further.”I think this scheme is just a massive gamble,” Mr Taylor said.According to Mr Taylor, who has rarely granted interviews, the “most fundamental flaw” in the modelling was a failure to acknowledge the extent of groundwater decline.He said it was “astonishing the Water Department would consider a model that does not take into account that declining groundwater levels could reliably predict future stream-flows”.Environment, not farmers, bear riskHe said the failure meant the irrigation scheme would be left short of the required run-off levels more often than not.”This is a classic example of how water over-allocation problems occur in Australia,” Mr Taylor said.The Southern Forests Irrigation Scheme would take river from karri forest by damming a tributary of the Donnelly River.(ABC South West: Anthony Pancia)”People proceed with schemes on optimistic predictions on future water availability.”People have made investments, put irrigation systems in their land. They’ve planted crops.”And then what happens is that governments often turn around and simply take more water from the environment and that causes great stress on the environment.He said this had been seen it over and over and over again in Australia and he could not see why it was happening in 2020. “With all the knowledge we have of the drying climate and water over-allocation problems that the Government would be proposing to build another large dam.”‘Responsible adaptation to climate change’Jeremy Bower, the chief executive of the SF Irrigation Co-operative, disputed the claims, saying the scheme had been consciously designed to avoid environmental risk.Mr Bower said the co-operative welcomed reasonable criticism of the project, but he argued Mr Taylor’s own assessment might have been too pessimistic in its assumptions.He said that under the modelling used by the department, there would be sufficient water available in future years to meet both commercial and environmental needs.SF Irrigation Co-operative is chaired by Harvey Giblett, one of WA’s biggest apple producers.”It’s very difficult to forecast that it’s going to just get drier and drier,” Mr Bower said.”We believe it may be a drying climate but even under the driest scenarios out to 2050, this project still delivers additional water to these growers who supply over 20 per cent of the state’s irrigated produce.Scheme ‘fit for purpose’: GovernmentSF Irrigation Co-operative chair Harvey Giblett believes the water project is worthwhile.(ABC Rural: Jon Daly)A spokesman for the department said while “models have limitations”, it was comfortable with its work to assess water availability for the irrigation scheme.He said the model it used was developed according to relevant guidelines and was “fit for purpose”.”Any water supply risks will be managed through rules which protect and prioritise environmental flows and by varying supply from year to year depending on available water,” the spokesman said.”Water will only be taken once there is sufficient flow to meet all environmental requirements.”All water availability risks will be borne by the scheme and not the environment.”$60m of taxpayers’ money on the lineUnderfunding announcements made so far, the State Government has promised $20 million while the Commonwealth has provided $40 million.The remaining $10 million has been pledged by farmers participating in the scheme.Mr Taylor said he was motivated to speak out over the project given the use of taxpayers’ money and questioned the state’s support.”I can’t understand why the Minister for Agriculture and the Minister for Water are still standing behind this scheme,” he said.”I think they actually do know now that the scheme is flawed and it’s high-risk.The department noted the project would be assessed by the Environmental Protection Authority, which would provide a period for public submissions.
Respected water expert says plans for a taxpayer-funded $70 million irrigation scheme in WA’s food bowl will be an environmental and financial disaster.