Tablelands regional water assessment

The Tablelands region’s economic growth is strongly linked to the agricultural industry. It depends on well-managed water supply and security that will continue to support agricultural development, as well as future urban and industrial sector growth.

Identifying options for investing in water is an important initial step towards realising the region’s future competitive opportunities and solidifying its status as one of Queensland’s most significant food bowl areas.

The Tablelands regional water assessment (RWA) involved strong collaboration with local councils, industry, Sunwater, Traditional Owners and community members, where 113 possible water initiatives were identified. After robust technical analysis and consultation, this list was reduced to the seven most viable options for detailed assessment.

Public consultation helped refine the final RWA, which identifies short, medium and long-term recommendations to improve water security and drive economic growth.

The RWA can be considered as the Queensland Government delivers its wider water agenda.

Status

The final assessment was completed in late 2023.

View the Tablelands RWA summary report (PDF,11MB).

Consultation

Stakeholder advisory group consultation included:

  • Advance Cairns
  • AgForce Queensland
  • Cairns Regional Council
  • Mareeba Shire Council
  • Queensland Farmers Federation
  • Regional Development Australia Tropical North
  • Sunwater
  • Tablelands Regional Council
  • Tinaroo Water Committee.

Assessment area

View a map of the Tablelands RWA area (PDF, 801KB).

Area summary

Local government areas

Includes Tablelands Regional Council, and parts of Mareeba Shire Council and Cairns Regional Council.

Water context

The Tablelands RWA area includes the Mareeba Dimbulah water supply scheme (MDWSS) and Lake Mitchell in the northern parts as well as the Johnstone River and Herbert River catchments within the Tablelands Regional Council area. The Tablelands RWA also considers provision of water supply outside the RWA area to Kuranda and Barron Gorge hydroelectric power station (supplied from Tinaroo Falls Dam) as well as future urban water demands for Cairns.

Snapshot of demographics

Population at the time of assessment ~48,783

Future Population (by 2050) estimated at the time of assessment ~59,000

Main population centres

Atherton, Mareeba

Smaller towns and cities

Herberton, Malanda, Millaa Millaa, Mount Garnet, Ravenshoe, Tolga, Yungaburra, Dimbulah

Key industries

Mining, timber production, tourism and diverse agriculture (mango, avocado, citrus, sugar, beef, etc)

Agricultural land use

Grazing, dryland and irrigated cropping, dairy cattle farming

Main water sources

Tinaroo Falls Dam, Atherton Basalt Aquifer

Other water sources

Herbert, The Millstream, Upper Johnstone, South Johnstone, Barron and Walsh Rivers

Water demand

Barron subarea

  • Includes large part of Barron catchment and part of the Upper Walsh and Upper Mitchell catchments.
  • Strong existing agricultural water use centred on the MDWSS in addition to unsupplemented water from watercourses and groundwater supporting agricultural production outside of the MDWSS.
  • Increasing agricultural water demand due to maturing tree crops, ongoing irrigation expansion and transition to high value crops in response to markets and opportunities.
  • Increased water demand due to climate change – increased temperatures and reduced rainfall.
  • Cairns Regional Council may require water in the medium to long-term.
  • Increasing water needs for towns and industrial growth.

Upper Herbert subarea

  • Herbert River catchment within Tablelands Regional Council.
  • Low to moderate existing irrigated agricultural production from unsupplemented water from watercourses and groundwater.
  • Increased irrigated agricultural production anticipated to be meet through existing water entitlements in the short-term.
  • Significant potential for growth given reserves of unallocated water and soils suitable for irrigated agriculture.
  • Future growth in water demand estimated to be small.
  • Climate change impacts are expected to be low to moderate due to low water use.

Upper Johnstone subarea

  • Johnstone River catchment within Tablelands Regional Council.
  • Low to moderate existing irrigated agricultural production from unsupplemented water from watercourses and groundwater.
  • Moderate potential for growth given reserves of unallocated water and limited land with suitable soils.
  • Future growth in water demand estimated to be minor, primarily associated with urban and industrial expansion.
  • Climate change impacts are expected to be low to moderate due to low water use.

Options to support water security and economic growth

The assessment process identified the most suitable ways to support the region’s water security and promote economic growth.

The most promising options that have not been subject to recent detailed assessment or being examined as part of other initiatives were considered for further detailed assessment, with input from local stakeholders.

A summary of the options considered for further detailed assessment are provided below. Further details are available in the Tablelands RWA summary report (PDF,11MB).

Non infrastructure options

Activation of high flow reserve

This option proposes the release of a portion of the unallocated water reserves in the Barron and Wet Tropics water plans through an expression of interest process and market mechanisms. The reserves include the "high flow reserve" from the Wet Tropics water plan and the general reserve from the Barron water plan.

Adjustments to the Barron Gorge hydropower release rule (Barron Gorge HRR)

This option explored modifying the hydropower release rule (Barron Gorge HRR) under an existing resource operations licence to provide more water to agricultural users. Through the RWA process, it was concluded that this option should not proceed further at this time, due to stakeholder feedback, alignment with clean energy objectives, and analysis of historic water release data.

Infrastructure options

MDWSS efficiency improvement project stage 2

Stage 2 of the MDWSS efficiency program builds on the success of stage 1, which was largely completed in December 2021.

North Johnstone diversion

This option aims to transfer unallocated high flow reserve water from the Johnstone River to Lake Tinaroo, increasing the water yield available from Tinaroo Falls Dam. This additional water would support expanded agricultural production in the MDWSS.

Lake Mitchell transfer

This option proposes pumping water from privately owned Lake Mitchell to the Barron River to offset water releases from Tinaroo Falls Dam. This would help meet the water requirements of the Barron Gorge HRR and environmental flow objectives, enabling additional water allocations from Tinaroo Falls Dam to support the MDWSS.

Glen Gordon off-stream storage

This option proposed the development of a centralised off-stream storage facility with associated distribution systems, supplied by water harvested from the Herbert River.

Nanyeta Creek off-stream storage

This option involves the development of a centralised off-stream storage supplied from the Herbert River.

Responding to the challenges and opportunities

Barron subarea

Activation of general reserve unallocated water

  • Release of general reserve unallocated water expected to provide significant economic benefit.
  • On-farm infrastructure investment would be privately funded and delivered by irrigators.

MDWSS efficiency project stage 2

  • While expected to yield lower volume than stage 1 it was still likely to result in a positive economic outcome.
  • Would also increase water supply reliability for key areas.

Lake Mitchell transfer option

  • Likely to result in positive economic outcome.
  • Further engagement with the owners of Lake Mitchell required to better understand access expectations and improved knowledge of the asset.
  • Further environmental investigations required to understand potential environmental risks from inter-catchment transfer.

North Johnstone diversion option

  • There are environmental, social and cultural considerations that require further investigation.
  • No positive economic outcome is likely unless the relative costs and benefits ratio improves as the region evolves.

Nullinga Dam

  • Not considered viable due to substantial cost and very poor economic benefit.

Upper Herbert and Upper Johnstone subareas

Activation of high flow reserve option

  • Release of high flow reserve unallocated water expected to provide significant economic benefit.
  • On-farm infrastructure investment would be privately funded and delivered by irrigators.

Glen Gordon and Nanyeta Creek Off-stream storage options

  • Both options were found to be unviable with high capital costs resulting in unaffordable water prices.

Possible larger water storages

  • There are other water supply options in the Upper Herbert that could be further investigated.
  • A localised options analysis in the future may be required to identify the best water security options to progress, informed by releases of high flow water reserve and bulk water supply and demand audit.

Recommendations and implementation

The Tablelands RWA prioritises recommendations for potential delivery over the next 30 years to approximately the early 2050s. These recommendations were made at the time of the assessment (2023) and do not signify Queensland Government approval or funding. However, the key findings and recommendations will help to inform the delivery of the Queensland Government’s water agenda.

The recommendations provided below represent those at the time of assessment and do not include any announcements, decisions or activities (government or private) that may have been made since the completion of the Tablelands RWA.

Short term

Barron subarea

  • Initiate a detailed business case for the MDWSS efficiency improvement project stage 2 option.
  • Seek to incorporate RWA outcomes into relevant state planning instruments.
  • The Department of Local Government, Water and Volunteers (DLGWV), Sunwater and Lake Mitchell owner to understand access expectations prior to undertaking a detailed business case for the Lake Mitchell Transfer option.
  • Review the alignment of the Lake Mitchell Transfer and North Johnstone Diversion options with relevant water plans.
  • Undertake an expression of interest for the release of general unallocated reserves in the Walsh catchment to inform release (timing, volume, and product details) via market mechanism.

Upper Herbert and Upper Johnstone subareas

  • Seek to incorporate RWA outcomes into relevant state planning instruments.
  • Undertake an expression of interest for the release of up to 4,000ML from high flow reserve in the Upper Herbert subarea to inform release (timing, volume, and product details) via market mechanism.
  • Undertake an expression of interest for the release of up to 2,000ML from high flow reserve in the Upper Johnstone subarea to inform release (timing, volume, and product details) via market mechanism and investigate the impact of high flow release thresholds on the viability of the North Johnstone Diversion option.

Medium term

Barron subarea

  • Implement the MDWSS efficiency improvement project stage 2 option subject to detailed business case outcomes.
  • Initiate a detailed business case for the Lake Mitchell Transfer option subject to the outcomes of:
    • DLGWV, Sunwater and Lake Mitchell owner’s shared understanding of access expectations for Lake Mitchell
    • a prior MDWSS bulk water supply and demand audit, including consideration of climate change risk.
  • Complete any subsequent release process initiated for the unallocated water referred to in the short-term action.

Upper Herbert and Upper Johnstone subareas

  • Complete any subsequent release process initiated for the unallocated water referred to in the short-term actions.

Long-term

Barron subarea

  • Consider climate/energy policy changes and conjunctive use of water for Cairns/Barron Gorge hydropower generation in the next Barron water plan review.
  • Initiate a detailed business case for the North Johnstone diversion option subject to the outcomes of:
    • review of the option’s alignment with relevant water plans
    • a prior MDWSS bulk water supply and demand audit, including consideration of climate change risk.

Upper Herbert and Upper Johnstone subareas

  • Review the take-up and development of any high flow reserve water released.
  • Complete an options analysis to supply additional water and/or reliability in the Upper Herbert subarea subject to the outcomes of:
    • any prior high flow reserve release processes
    • a prior bulk water supply and demand audit, including consideration of climate change risk and capacity/willingness to pay for water.
  • Consider the above options analysis and any recommendations it makes on progressing a preferred supply source to a detailed business case.
  • Subject to outcomes from above and short and medium-term actions, initiate further planning for additional water supply sources in the Upper Herbert subarea, if required. This could also involve the release of additional high flow reserve water entitlement depending on effectiveness of take-up and development of earlier releases.

Recurrent recommendations

Barron subarea

  • Bulk water supply and demand audit for the MDWSS, including consideration of climate change risk, every 5 years.
  • Review benefits/opportunities surrounding releases from Tinaroo Falls Dam for hydropower generation every 10 years.

Upper Herbert and Upper Johnstone subareas

  • Bulk water supply and demand audit, including consideration of climate change risk and capacity/willingness to pay, every 5 years.

Enquiries

Contact regionalwaterassessments@dlgwv.qld.gov.au.