Southern Forest Irrigation Scheme won’t work says former Director General

Kim Taylor is the former Director General of the Department of Water in Western Australia and gives his reasons why he believes the scheme will fail

According to Kim Taylor, streamflow in the Donnelly River has already declined by 70% since 1975 due to drying climate

According to Kim Taylor there is not enough water for the proposed scheme and it will also have a huge impact on the Donnelly River.

But the current State Government refuses to listens to him.

Kim Taylor outlines why he believes the Southern Forest Irrigation Scheme will fail.

300Kim Taylor, former Director General of the Department of Water in Western Australia

The Southern Forest Irrigation Scheme involves

  • Constructing a dam in State forest on Record Brook to capture inflow from that brook, and
  • Taking water from the Donnelly river also to pump to the dam.
  • More than $5m of taxpayers money has already been spent on planning and investigations for the scheme;
  • The Stat Government has committed about $20m for construction of the scheme and the Federal Government $40m.

Kim Taylor’s background: 

  • I worked for 40 years in government.
  • I worked for 20 years in water resources assessment and management working in the Water Authority, Water and River Commission and Department of Water, including 2 years as Director General of the Department of Water.
  • I also worked for 20 years in environmental impact assessment working in the Department of Environment and Office of the Environmental Protection Authority (EPA), including seven years as General Manager of the Office of EPA. 

Is Kim Taylor being paid to make these comments: 

  • I have not been engaged by any party to comment on the Southern Forest Irrigation Scheme and I make these comments merely as a concerned person with background experience in water resources assessment and management.
  • I am particular concerned about the potential waste of $60 million of taxpayers funds on the scheme, and impacts on the river environment which is already being impacted by drying climate. 

The proposed scheme is a massive gamble on future streamflows in south-west WA according to Kim Taylor: 

  • This scheme is a massive gamble by the Government on future streamflow in the south-west of WA, an area that the Minister for Water Resources has stated himself as being ‘one of the areas on the planet most affected by climate change due to declining rainfall.’
  • Streamflow in the Donnelly River has already declined by 70 % since 1975 due to drying climate.  With expected further reductions in rainfall, streamflow is likely to reduce to less than 10 % of historical flows (see attached graph at end of story). 
  • A government Expert Panel which reviewed forestry management in the SW of WA has also stated that:
  • In the Panel’s view the need for forest management to achieve a better water balance in a drying climate is the most critical issue facing the forests in the south-west now and in the future.
  • The forest ecosystems are already experiencing acute water stress. If this issue is not addressed as a matter of priority, then the consequences will be undesirable, probably irreversible, and will likely compromise efforts to achieve Environmentally Sustainable Forrest Manage. 
  • The scheme is a massive gamble on future streamflow, a gamble of $60 million of taxpayers’ money, and a gamble on the river environment which is already highly stressed due to drying climate.

Kim Taylor asks why the Government is still proceeding with the scheme and adds his reasons: 

  • It is hard to comprehend why the Government is proceeding with the scheme.
  • An economic analysis of the scheme was undertaken in 2016.  That was based on forecast at the time that the scheme could reliably supply around Gigalitres of water 95%, that is in 95% of years, even under a drying climate.  It appears no detailed catchment modelling had been done at that time, as the Water department’s catchment modelling was not released until December 2018.
  • Despite no detailed modelling having been done, the Southern Forest Irrigation Cooperative was established in May 2017 and preliminary water sales were made from the scheme in November 2017.  All this before any catchment modelling.
  • The catchment modelling released in December 2018 showed that the scheme would not be able to supply 9 GL at high reliability as used in the Economic Analysis.  The modelling report showed that the scheme would be able to supply 9 GL of water in only about 50% to 70% of years by 2030 under dry and medium future rainfall forecasts, well below the 95% used in the Economic Analysis.
  • Despite this, in August 2019 both the Minister for Agriculture, Minister MacTiernan, and the Water department stated in a parliamentary inquiry into the scheme that the catchment modelling showed the scheme could ‘provide 9 GL of water in 80-97% of years’ in 2030.
  • What is even more damming and alarming, however, is that based on streamflow gauging of the Donnelly river over the last 10 years, the scheme would have been only able to meet the required supply in only about 40% of years based on those streamflow.  By 2030 the reliability would be much less than this due to further rainfall decline, the reliability probably being 20% or less. 
  • What the lower reliability means in terms of how much water the scheme could supply is that while the Minister for Agriculture and Water department have been saying the scheme will be able to supply around 9 GL per year, based on streamflow in the Donnelly River over the last 10 years the scheme would be able to supply only around 6 GL/year if built now, and would only be likely to be able to supply around 3 GL/year or less by 2050.
  • That is, the proposed scheme could not provide anywhere near the amount of water used in the 2016 Economic Analysis; or that predicted by the Water department’s catchment modelling in December 2018; or that stated by the Minister for Agriculture and Water department to the parliamentary inquiry in August 2019.
  • The Water department and Ministers should have been aware of this by the time they were making submissions to the parliamentary inquiry, but made no reference to this.
  • As far as I am aware the Government has never formally advised the Irrigation Cooperative or the public that the scheme will not be able to provide 9 GL of water per year at high reliability.
  • l believe the Ministers for Agriculture and Water, Ministers MacTiernan and Kelly, know that this is a risky scheme and that the Water department’s  assessment of the supply is flawed but they don’t want to admit this ahead of the election.
  • Their response now has just been that they are going to put the scheme through the EPA’s environmental approval process.  There are a number flaws with this approach.
    1. Firstly, it will take about 2 years to go through the EPA process and subsequent appeal processes. This will result in another $2 to 3 millions of taxpayers funds being wasted on a scheme which is clearly flawed;
    2. Secondly, there are many farmers in Manjimup who are very concerned that their access to water will be affected by the scheme and they’ll have to endure another 2 years of uncertainty if the Government proceeds with the environmental approvals process;
    3. Thirdly, I understand that some businesses are actually starting to plant crops based on the expectation that they will get water from the scheme in the coming years. The longer this scheme is drawn out the more likely it is that these people are going to lose their money due to inadequate water. 

The Water department says that its catchment modelling shows that the scheme can reliably supply 9 gigalitres a year.  Is this reliable asks Kim Taylor:

According to Kim Taylor, the streamflow of the Donnelly river over the past 10 years would only be able to meet 40% of required supply
  • The Consultants that developed the catchment model for the Water department (Hydrology and Risk Consultants) actually stated in their report to the departmentthat there is ‘High uncertainty’ in the model’s results of predicted future streamflow.  The Consultants also indicated that the certainty of the modelling was affected by the time and budget available for the modelling.
  • The most fundamental flaw in the modelling is that does not take into account the long-term declining groundwater levels in the catchment.  It is well established that long-term declining groundwater levels are a major cause of the reducing streamflow as this results in disconnection between groundwater and streams in areas close to streambeds, and a major reduction in rainfall runoff generation.
  • It is astonishing that the Water department would consider that a model which does not take into account declining groundwater levels could reliably predict future streamflow in a drying climate.
  • Another example of the flaws in the modelling is the lack of streamflow monitoring at key locations in the catchments.  The scheme involves constructing a dam within State forest on Record Brook.  The Water department has not done any streamflow gauging on Record brook for 20 years.  Their model has been calibrated based on rainfall and runoff for the brook from 1988 to 2000.  This was a much wetter time and does not provide a reliable model of current, or likely future runoff.
  • The Water department’s model predicts that there will be about 3 GL of runoff from Record Brook into the dam in 2030 under their future climate scenario.
  • There has been a group of farmers who have been monitoring streamflow at a number of key locations in the in the area over the last three winters, because the Water department has not been monitoring many points.  The farmers’ monitoring showed that there was only about a half a gigalitre of total flow in the brook this winter which was an average to slightly above average rainfall for the area.  That is, the current streamflow in Record Brook is not even enough to meet the desired environmental flow.
  • Surprisingly, after receiving the advice from their initial Consultants that there was ‘High uncertainty’ in the modelling, the Water department then engaged a second Consulting company to review the report in what appears to be an attempt to override the initial Consultants’ professional advice. 
  • The review carried out by Eco Logical found simply that the modelling was ‘fit for intended purpose’, being the department’s water planning and management, but noted that there were aspects of the modelling that should be reviewed and adjusted to provide greater robustness to the modelling ‘for other purposes’ which would include being used for the environmental approval process and Investment Decision on the scheme.  The review made 14 recommendations including that streamflow – groundwater interaction should be incorporated into the modelling so declining groundwater levels would be taken into account. 
  • It can be seen from both Consultants’ advice to the Water department that at this stage the scheme is just a massive gamble on future streamflow. 
  • If the Government wants to take a gamble, it should at least have the best reliable catchment modelling it can to make its decision.  The current modelling does not meet this.
  • The State’s Treasury Department should be taking a much more active interest in the scheme and its viability, as well as the Federal Department of Infrastructure which is responsible for the Commonwealth money. 

This is what the Government should do, according to Kim Taylor:

  • There is certainly a need for water infrastructure in the Manjimup area to assist the horticulture industry, which is important to the State, to adapt to the drying climate.  Building a large new dam in State forest which is a massive gamble is not the way to go.  While jobs are important, gambling $60 million dollars of taxpayers funds and putting the environmental at risk on this scheme  is not sound for the projected 150 permanent jobs the scheme would create.
  • The Government and Water department should admit that the existing proposed scheme is flawed and go back to the drawing board.  They should work with the horticulture industry in the area to seek to develop a more sustainable way to optimising use of water in the area, in an environmentally sustainable way. This is what the people I’ve spoken to in area would like to see.
  •  The Government’s current approach of simply sitting on its hands and saying that they will put the current scheme through the environmental approval process is not good government.

Average annual streamflow in Donnelly River at Chappells Bridge  where the proposed Southern Forest Irrigation Scheme would abstract water 

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