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Last Updated: Thursday, 06 July 2023 10:10
Water Vision 2071 provides an integrated water security and wastewater servicing strategy for the next 50 years, supporting prosperous growth forecasts and addressing key challenges to servicing the Region
Introduction
This article is a summarised version of the detailed Water Vision 2071 presented to Council by consulting engineers in February 2023.
Water Vision 2071 is a technical guiding document to assist decision-makers in managing of our water resources, now and into the future. Underpinned by Toowoomba Regional Council’s five corporate goals – people, place, sustainability, prosperity and performance – the document is designed to assist future planning supported by investigations, costing and options assessments.
An ‘all options on the table’ approach was taken in developing Water Vision 2071. The assessment considered the demand and supply sides of the water balance, centralised and decentralised supply arrangements, and opportunities to make the best possible use of existing
infrastructure and supply sources.
On completion of supporting investigations, this Vision will assist Council in making informed decisions. This Vision is intended to be reviewed and updated regularly.
Summary
Our Region has a variety of feasible options from which to choose to ensure a reliable water system across the planning horizon (until 2071).
Reliable ongoing water systems will require the continued and increased use of existing water sources for both the Toowoomba Bulk Water Supply and regional systems.
From mid-2040, the introduction of a new water source or a major investment in new infrastructure from Wivenhoe Dam will be required for the Toowoomba Bulk Water Supply.
2024 - Increase water treatment plant capacity
2027 - Increase allocation from Wivenhoe
By 2027 - Secure water supply to Cambooya, Greenmount, Nobby & Clifton via the Toowoomba to Warwick Pipeline
2032 - Increase pumping capacity from Cressbrook
2040 - Upgrade Wivenhoe pumps & increase allocation
Late 2040s- Alternate water supply or addition allocation, pipe and pumps from Wivenhoe.
Our water systems
The system
This is the largest system in our Region, providing greater than 90% of town water used by residents and businesses. Water is delivered to 60,000 connections via more than 1,850 km of pipelines, 50 reservoirs and 30 pump stations.
Most of this system's water is sourced from Cressbrook, Perseverance and Cooby Dams. Additionally, Wivenhoe Dam (owned by Seqwater) provides a limited backup supply. The Toowoomba City area is also supplemented
by over 20 local groundwater bores contributing 10-20% of the system’s supply.
Water treatment primarily occurs at the Mt Kynoch Water Treatment Plant. Treatment also occurs at the smaller Pechey, Cressbrook and Perseverance water treatment plants.
Short-term projects
This Vision assumes the progress of the following short-term projects:
- Connection of Vale View to the Bulk Water Supply. This project commenced with planning in 2021.
- Interim upgrade of Mt Kynoch water treatment plant to 65 ML/d by 2025. This project commenced in 2022.
- Upgrade Pechey gravity mains to 71.5 ML/d by 2025. This project commenced in 2018.
- Connection of Clifton, Greenmount, Nobby and Cambooya by 2027. With the progression of the Queensland State Government’s Toowoomba to Warwick pipeline, this will include a new water treatment plant with pipelines connecting these towns.
- Increase annual entitlement from the Cressbrook- Perseverance system from 14 GL/y to 20 GL/y by 2025 through an amendment to the existing Resource Operating Plan or similar instrument.
- Increase in allocation from Wivenhoe Dam from 10 GL/y to 13.1 GL/y and modify operational trigger from 40% to 50% of the Full Supply Volume in Cressbrook Dam by 2027.
- Upgrade Cressbrook pumping system to 53 ML/d by 2034.
- Upgrade Mt Kynoch water treatment plant (Stage 1) to 75 ML/d by 2034.
Bulk water supply challenges
The demands on this system are predicted to exceed 29,000ML/y by 2071, with a total deficit of 6,222ML/y based on existing annual entitlement volumes. Water security modelling suggests that this deficit increases to 7,624ML/y when considering the system's capacity to supply demands while meeting the defined level of service criteria, such as minimising time spent in water restrictions.
Response actions to meet predicted supply shortfall
This deficit is proposed to be met by a combination of actions which were developed under three portfolios:
1. Using existing supplies – maximising supply via existing water sources.
2. Finding alternative water – exploring opportunities for making the best use of locally produced recycled water.
3. Sourcing regional water – seek agreement for water supply from a new regional supply source, preferably from a large catchment that may provide higher reliability
Blue-sky options
‘Blue-sky’ options include any conceivable solution without consideration for practicality or expense. The following bluesky options were considered:
Surface water
- New dams in the Toowoomba Region
- External dams in nearby regions and interstate.
- Improvements to existing Council dams – Eg: minimising evaporation and raising dam walls
- Further use of rainwater tanks
- Seqwater bulk supply – including further use of Wivenhoe Dam.
Groundwater
- Existing sources within TRC – alluvium and Great Artesian Basin
- New bores within our Region
- Bore purchasing or shifting of allocations
- Purchasing nearby entitlements
- Aquifer recharging.
Non-potable water
- Purified recycled water
- Stormwater harvesting
- Coal seam gas water, sewer mining etc
- Greywater
- Desalination.
Other
- Demand reduction measures
- Leakage and pressure management
- Cloud seeding, fog or dew collection, capturing condensation
- Oxidising hydrogen
- Glaciers and ice caps.
Multi-criteria analysis
Blue-sky options were then assessed against various criteria including:
- Sustainable capacity/yield
- Proximity to source
- Technology readiness
- Water quality and environmental issues
- TRC corporate goals
- Resilience/water security
- Cost to supply.
The following graph illustrates the multi-criteria analysis summary for bulk water options with a cost below $1,500/ML.
The system
The framework for the water supply strategy to rural townships is based on 2071 demands considering the following:
• Local water supply licences or allocation limits
• The capacity of existing bore or surface water extraction
infrastructure
• Historic reliability of supply
• Current treatment infrastructure suitability and capacity
• Raw water quality.
Systems within this scheme include:
Most efficient options
It is recognised that a single water source may be unlikely to satisfy the full supply deficit for the 50-year planning horizon to 2071.
The best-performing option was a new Wivenhoe pump station. This includes the installation of a larger pump station being installed to match the capacity of the existing pipeline. This is included in all option portfolios below. While it does not meet the 2071 deficit in supply alone (providing an additional 3,300ML/y of the required 6,222), it is a low-cost and low-impact solution that will also delay the requirement for additional supply. The low-cost, high-performing option of whole-of-system leakage reduction is included in all portfolio options below. The high-performing option of direct potable reuse was not progressed as it is not able to be commissioned under current legislation in Australia. The most efficient options were categorised into the following portfolios with consideration given to existing infrastructure capacity, pre-existing projects and planning (planned base case), and the total water deficit to 2071.
Portfolio 1 is characterised by the increased utilisation of existing Council infrastructure and supply sources. An infrastructure program could include the following:
- 2025 – Increase the Cressbrook-Perseverance system entitlement from 14 to 20 GL/y*.
- 2027 – Increase the Wivenhoe entitlement from 10 to 13.1 GL/y and modify operating rules for the Wivenhoe Pump Station to commence pumping at 50% (up from the current 40%)*.
- 2032 – Cressbrook system transfer capacity upgrade Stage 1: Upgrade the Cressbrook pump station from 44.1 to 53 ML/d to match pipeline capacity*.
- 2040 – Increase the Wivenhoe entitlement – from 13.1 to 16.4 GL/y. Wivenhoe system transfer capacity upgrades Stage 1 – Upgrade Wivenhoe pump station to 45 ML/d to match pipeline capacity.
- 2044 - Increase Pechey gravity main to 95/ML/d.
- 2046 – Increase the Cressbrook-Perseverance system entitlement from 20 to 26.2 GL/y.
- 2048 – Cressbrook system transfer capacity upgrade Stage 2: Upgrade Cressbrook pump station and pipeline from 53 to 78 ML/d.
- 2054 – Increase Wivenhoe entitlement from 16.4 to 21 GL/y.
- 2054 – Wivenhoe system transfer capacity Stage 2: Upgrade Wivenhoe pump station and pipeline from 45 to 57.5 ML/d through pipeline duplication.
* Already in progress or included in current short-term planning.
Portfolio 2 is characterised by adopting alternative water supplies (primarily recycled water from the Wetalla Water Reclamation Facility) to supplement the current raw water supply arrangements. This portfolio could be delivered by the following infrastructure program:
- 2025 – Increase the Cressbrook-Perseverance system entitlement from 14 to 20 GL/y*.
- 2027 – Increase Wivenhoe entitlement from 10 to 13.1 GL/y and modify operating rules from 40/50% to 50/60% full supply volume at Cressbrook Dam*.
- 2032 – Cressbrook system transfer capacity upgrade Stage 1 – Upgrade Cressbrook pump station from 44.1 to 53 ML/d to match pipeline capacity*.
- 2040 – Increase the Wivenhoe entitlement from 13.1 to 16.4 GL/y.
- 2040 – Wivenhoe system transfer capacity upgrade Stage 1: Upgrade Wivenhoe pump station to 45 ML/d to match pipeline capacity.
- 2046 – Increase the Cressbrook-Perseverance system entitlement from 20 to 20.8 GL/y.
- 2048 – Cressbrook system transfer capacity upgrade Stage 2: Upgrade the Cressbrook pump station and pipeline from 53 to 63 ML/d.
- 2049 – Introduce purified recycled water to Cooby Dam (up to 15 ML/d).
* Already in progress or included in current short-term planning.
Portfolio 3 is characterised by accessing supply from major surface water dams outside of our Region to supplement current raw water supply arrangements. Significant time is required to coordinate all feasibility assessments, community engagement, environmental impacts, regulatory changes, engineering design and funding to facilitate the connection to a regional supply source. Therefore, the Wivenhoe pump upgrade and increase in entitlement are
recommended to maximise available lead time. Shortlisted possible regional supply sources include:
- Emu Creek Dam
- Coolmunda Dam
- Boondooma Dam
- Wyaralong Dam
- Clarence River Dam
- Lockyer Creek Dam
- Mole River Dam (proposed dam in NSW). An infrastructure program could include:
- 2025 – Increase the Cressbrook-Perseverance system entitlement from 14 to 20 GL/y*.
- 2027 – Increase the Wivenhoe entitlement from 10 to 13.1 GL/y and modify operating rules from 40% to 50% full supply volume at Cressbrook Dam*.
- 2032 – Cressbrook system transfer capacity upgrade Stage 1: Upgrade the Cressbrook pump station from 44.1 to 53 ML/d to match pipeline capacity*.
- 2040 – Increase the Wivenhoe entitlement from 13.1 to 16.4 GL/y.
- 2040 – Wivenhoe system transfer capacity upgrade Stage 1: Upgrade Wivenhoe pump station to 45 ML/d to match pipeline capacity.
- 2044 – Increase the Pechey Gravity Main capacity to 95 ML/d
- 2046 – Introduce a new regional raw water supply.
* Already in progress or included in current short-term planning.
Regional systems with supply challenges
The following systems have water supply challenges and recommended actions to maintain sustainable systems through the planning period.
• The system has limited redundancy to allow downtime for maintenance.
• There is sufficient water entitlement to 2071. However, the system has limited sustainable yield when accounting for the required dilution and mixing requirements of bores.
• Options that proposed integration into the Bulk Water Supply were previously found to be cost-prohibitive.
• Strategic action: The suitable location and construction of an additional alluvial bore near Pittsworth is recommended.
• Projected water demands and water entitlement limits show there are events in which no supply is available from the weir (Eg: during drought where water quality worsens) and supply capacity from the Nukku pipeline alone is insufficient to meet demands.
• Water treatment plant operational issues must be resolved for continued use over the planning horizon.
• Options that proposed integration into the Bulk Water Supply were previously found to be cost-prohibitive.
• Strategic action: An additional raw water supply source is recommended to enhance water security and reliability of supply for Yarraman. An increase in entitlement from Boondooma Dam via South Burnett Regional Council with the blending of raw water from the Ted Pukallus Weir at a very diluted rate is considered to be the most cost-effective and feasible option. This option will provide long-term security to supply and is recommended to be investigated in the short term.
Our wastewater systems
Located in Cranley, Wetalla is a centralised wastewater treatment facility servicing Toowoomba City and several major townships.
The current average day demand is 20.7 ML/y. The estimated average day demand in 2071 will be 36.9 ML/d.
System challenges - The Wetalla water reclamation facility is forecast to reach capacity in 2050 with a 7ML/d deficit in 2071.
Response actions - Two preferred options were identified to either maintain and upgrade the Wetalla water reclamation facility or diversify with a southern water reclamation facility. A southern facility would service existing and future growth areas to the south and southwest of Toowoomba City.
TRC owns and operates decentralised sewage systems in several rural communities that are not connected to the centralised (Wetalla) sewage scheme.
Short-term projects
• Upgrade the Crows Nest sewer system from a common effluent disposal system to a conventional sewer system.
• Upgrade the Clifton sewerage treatment plant.
Future work
• 2042 – Increase treatment capacity for the Pittsworth treatment plant.
• 2056 – Increase treatment capacity for the Clifton treatment plant.
• 2063 – Increase treatment capacity for the Crows Nest treatment plant.
Water Vision 2071 document
To view the entire document, please contact us.
