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Artist impression of the upgrades for the Lake Macdonald Dam Improvement Program - right side view
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Lake Macdonald Dam Improvement Project

Seqwater is upgrading Noosa’s Lake Macdonald (Six Mile Creek) Dam as part of its Dam Improvement Program. Site preparation works are planned for late 2024.

Home What We're Doing Lake Macdonald Dam Improvement Project

About the project

Dams are long-life assets which require continual assessment, monitoring and maintenance. South East Queensland dams were built to high safety standards, but most were built some decades ago. Methodologies and data used to estimate extreme rainfall events continue to improve and industry engineering standards and understanding of risks can progress over time. 

Across Queensland and Australia, there are multiple dam upgrades occurring to meet modern engineering standards. 

Seqwater’s Dam Improvement Program is ensuring its dams comply with the latest safety standards and continue to function safely during extreme weather events in line with regulatory requirements.  

The Lake Macdonald Dam Improvement Project will involve building a new spillway and reconstructing the existing earth embankments. 

The project will reduce risks associated with extreme weather events, achieve regulatory compliance, and ensure the continued reliability of this water source for the Sunshine Coast region for years to come.  

The project is expected to support 150 jobs throughout construction, with John Holland appointed as the major contractor. 

Project timeline

    Community engagement summary

    Seqwater released the project concept design and undertook targeted engagement with adjacent residents and stakeholders in January 2024. In February and March 2024, Seqwater held four drop-in community information sessions in Cooroy and Pomona, with 84 attendees.

    The community information sessions were promoted in a newsletter that was distributed to around 5,000 properties, emailed to around 580 recipients on the project database and promoted on social and local media.

    Throughout this community engagement, key themes were raised which the project team are carefully considering as part of project development.

    Some of the key themes raised during this period of community engagement were traffic and noise impacts, length of the revised project duration, fish relocation, and where construction materials will be sourced. 

    At this time, the construction contractor, John Hollan, who is responsible for engaging quarries, as well as other business suppliers for the successful delivery of the project, have not yet commenced this process and therefore a decision has not been made on where the construction materials will be sourced from. 

    In addition, the traffic management and construction impact mitigations are still being worked through and we aim to have these finalised shortly to provide more information on plans to reduce community construction impacts. 

    View the full community engagement summary report here

    Thank you to everyone who participated in the community information sessions. 

    Project update

    Project update

    Throughout 2021 and 2022, Seqwater worked with a Technical Review Panel to evaluate and short-list options for the Lake Macdonald Dam Improvement Project.

    In 2023, Seqwater worked through the preferred design option, completed the environmental and economic studies, and commenced project approvals, including approval of the supplementary business case.

    The project is progressing, with planning and onsite works continuing in 2024 focusing on site preparation ahead of project construction. 

    The revised project design and construction of the cofferdam released by Seqwater earlier this year takes into account feedback from the community, as well as water security considerations, to keep more water in the lake. 

    The cofferdam will deliver a number of benefits during the construction period including water security, environmental and community amenity, in addition to enabling some recreation activities to continue throughout the project. 

    Once final preparations and planning to construct the cofferdam are complete, construction is expected to commence in 2025, following this year's wet season which is also the breeding season for local aquatic species. 

    Seqwater is committed to reducing impacts to the environment. The project team is working closely with various levels of government and environmental experts to ensure that the project adequately addresses environmental considerations. 

    In 2024, Seqwater and John Holland will continue to conduct planning and site preparation works which include geotechnical investigations, survey works, earthworks on Seqwater property, water quality testing, and continued engagement with the community and traditional owners. 

    Design 

    Lake Macdonald Dam Improvement Project split level labyrinth spillway layout design

    This image shows the new split level spillway layout, including the upper labyrinth spillway (zigzag portion of the dam wall), and the new embankment. 

    The design for the new dam wall at Lake Macdonald is a split-level concrete spillway. The primary 'lower ogee' spillway is set at the original lake level, and an upper labyrinth spillway for higher floods.  

    A labyrinth spillway is an overflow weir, zigzag in shape which creates a longer total effective length over the spillway to enable higher flows caused by large rain events. The labyrinth spillway provides an efficient means of increasing spillway capacity without raising the dam’s crest.  

    The earth embankments will be reconstructed to their original level on either side of the spillway. 

    Scour protection will be an addition, with rocks placed downstream of the spillway to prevent erosion.  

    An outlet tower will be constructed to the left side of the spillway which will have mechanical pipework and electrical components to facilitate both emergency release of water, to lower the dam reservoir, and environmental flows to the downstream Six Mile Creek.  

    At completion of the project, the new dam will have the same storage volume and full supply level as the existing dam (storage to 8,000ML).

    Project scope 

    The Lake Macdonald Dam Improvement Project will include:  

    • Lowering of the Lake Macdonald water storage to accommodate construction. Seqwater has worked to minimise this impact, with a temporary water level that will be reduced by approximately 2 metres, from the full supply level (technically speaking this will be at RL 93m or 42%). This water level will provide water security reliability for the Noosa community and maintain access to the lake and local ambience.  
    • Relocation of fish by expert fish biologists, via a purpose-built fish transport vehicle, to Cooloolabin Dam. 
    • Construction of a cofferdam to protect the site and manage flows in Six Mile Creek during construction. 
    • Demolition of the existing spillway and dam wall. 
    • Removal of unsuitable foundation material under the new spillway, excavating down to a rock foundation, then backfilling with mass concrete. 
    • Construction of a split-level concrete spillway. The primary spillway will be set at the original lake level, and an upper labyrinth spillway will be constructed for large floods.  
    • Removal and reconstruction of the earth embankments on either side of the primary spillway.  
    • Ground improvement works below the new embankments. 
    • Provision of a new outlet works structure to enable environmental releases downstream of the dam into Six Mile Creek. 

    Additional works include fish protection measures (including proposed construction of a fishway at Gympie Weir), land management activities and rehabilitation.   

    Upstream cofferdam  

    A cofferdam structure will be built to undertake the construction work safely. A cofferdam is an enclosure built within a body of water to allow the enclosed area to be pumped out or drained. The pumping creates a dry working environment so that the dam wall construction work can be carried out safely.  

    The cofferdam for the Lake Macdonald Dam Improvement Project will be:  

    • 300 metres long 
    • 10 metres wide   
    • Approximately the same height as the current dam wall. 

    This is a temporary measure for dam safety during construction and once the new dam wall is complete, the cofferdam will be removed, and the dam will naturally refill to its original full supply level. 

    Minor lake lowering

    Seqwater has worked to minimise environmental impacts from this project, with a revised construction methodology that will temporarily reduce the water level by approximately 2 metres, from the full supply level. 

    Technically speaking, Lake Macdonald will sit at about 42 per cent of its full supply level (or 93 metres). 

    This reduced water level will allow the construction work to safely take place. The lake will remain at this level throughout construction unless dry conditions create a naturally lower level.  

    The Noosa Water Treatment Plant will continue to be operated as per the annual operating strategy and the monthly operational supply schedule (currently 20ML/d on average). 

    For more information

    If you have any questions about the project, please see the project FAQs below, or get in contact with the project team.

    Phone us: 07 3432 7000 (Monday to Friday, 9am to 5pm)

    Email the team: [email protected]

    Stay informed as this project progresses, by signing up to project updates below.

    • Project updates
    • FAQs
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    • Lake Macdonald

      Geotechnical investigation works underway on Lake Macdonald Dam Improvement Project

      Seqwater’s Lake Macdonald Dam Improvement Project is progressing, with geotechnical investigations underway.

      Part of Seqwater’s Dam Improvement Program, the Lake Macdonald Dam Improvement Project will ensure the dam continues to operate safely into the future and provide water security for years to come.

      Seqwater awarded the construction contract to John Holland Queensland in February 2024, and the geotechnical investigations will confirm the requirements for the project’s temporary cofferdam, which will deliver several benefits to the local community and environment throughout construction.

      Planning and site preparation works will continue in 2024 and include survey works, water quality testing, installation of project fencing, and continued engagement with the community and traditional owners.

      Seqwater’s Interim CEO, Will Harpham, said Seqwater is committed to the delivery of this critical project to ensure this important water source continues to serve the Sunshine Coast community now and into the future.

      “Part of Seqwater’s Dam Improvement Program, the Lake Macdonald Dam Improvement Project will ensure the dam meets modern engineering standards, continues to operate safely during extreme weather events, and provides water security for generations to come,” Mr Harpham said.

      “While Lake Macdonald Dam continues to operate safely, dam design and engineering standards, along with knowledge of weather and flood risks, have evolved since the dam was originally constructed in 1965, so this upgrade is about ensuring the longevity of the dam into the future,” he said.

      The project involves building a new split-level concrete spillway and upper labyrinth and reconstructing the existing earth embankments.

      The project temporary works design, which was released by Seqwater earlier this year, includes the installation of an upstream cofferdam to keep the lake water level as high as possible for water security, the environment, some recreation activities, and community amenity throughout construction.

      Seqwater is working through the construction methodology based on the design, and major works, including the installation of a temporary cofferdam, are expected to commence in 2025 after this year’s wet season.

      The Lake Macdonald Dam Improvement Project is expected to support approximately 150 jobs over the life of the project, and Seqwater is committed to keeping the community informed as this important project progresses.

      Lake Macdonald

      John Holland awarded Lake Macdonald Dam Improvement Project construction contract

      Seqwater has awarded John Holland the construction contract for the upgrade of Noosa’s Lake Macdonald (Six Mile Creek) Dam.

      Part of Seqwater’s Dam Improvement Program, the upgrade will enhance water security and enable the dam to withstand extreme weather events.

      The project involves building a new split-level concrete spillway and upper labyrinth and reconstructing the existing earth embankments. 

      Major site construction activities will commence later in the year.

      Drone shot of a crystal blue lake with a wide concrete spillway

      Community info sessions begin for Lake Macdonald Dam Improvement Project

      Seqwater has released the final design concept for the upgrade of Noosa’s Lake Macdonald (Six Mile Creek) Dam, with early works commencing ahead of major construction in mid-2024.   

      Part of Seqwater’s Dam Improvement Program, the upgrade will enhance water security and enable the dam to withstand extreme weather events. 
      Seqwater is committed to keeping the community informed throughout the project and will hold community information drop-in sessions in February and March, where the project team will be available to talk through the design and construction approach and answer any questions.

      Community Information Drop-In Sessions:
      Cooroy Memorial Hall:
      •    Tuesday 13 February: 2:30pm – 5:00pm, Cooroy Memorial Hall 
      •    Monday 19 February: 9:30am – 12:00noon, Cooroy Memorial Hall 
      •    Tuesday 19 March: 2:30pm – 5:00pm, Cooroy Memorial Hall 
      Pomona Memorial Hall: 
      •    Saturday 2 March: 9:30am – 12noon, Pomona Memorial Hall 

       

      Lake Macdonald

      Early works begin on Noosa’s Lake Macdonald Dam Improvement Project

      • Early works on the Lake Macdonald Dam Improvement Project have commenced, ahead of major construction mid-2024
      • Creating 150 jobs for Sunshine Coast locals
      • New split-level concrete spillway to increase the dam’s capacity to withstand extreme weather events, and maintain water security

      Seqwater has released the final design concept for the upgrade of Noosa’s Lake Macdonald (Six Mile Creek) Dam, with early works commencing ahead of major construction in mid-2024. 

      Part of Seqwater’s Dam Improvement Program, this upgrade will enhance water security and enable the dam to withstand a 1 in 500,000-year flood event.

      The dam improvement project involves building a new split-level concrete spillway and upper labyrinth and reconstructing the existing earth embankments. 

      Following a comprehensive technical review undertaken in 2021 and 2022, the new optimised design will increase the dam’s capacity to withstand extreme weather events while also ensuring the dam remains operational during construction for water security and some recreation activities.

      Seqwater has worked hard to keep the lake water level as high as possible during construction. The lake will be temporarily lowered for construction work to occur safely, and a temporary cofferdam will be installed to support water security during construction. The Noosa Water Treatment Plant will continue to operate during construction.

      This will be the first major upgrade of Lake Macdonald Dam since its original construction in 1965. Importantly, more than 150 local jobs are expected to be created over the life of the project.  

      Survey works are currently underway on-site, with site establishment and lake lowering occurring over the coming months. Major work to construct the temporary cofferdam is expected to commence mid-2024, following contractor appointment.

      Due to the significant nature of the project, some recreational use of the lake and surrounding areas will be disrupted during construction. However, recreation activities at Lake Macdonald, Lake Macdonald Park and the Noosa Botanic Gardens will remain open.

      Seqwater will keep the community informed throughout the project and will hold information sessions early-2024 where the project team will be available to talk through the design and construction approach and answer any questions. 

      Quotes attributable to Minister for Water, Glenn Butcher:

      “I’m pleased to see progress on this critical project. This important upgrade will ensure the longevity of Lake Macdonald Dam so it can continue to provide water security and dam safety for years to come. 

      “Dams in Queensland are built to very high, internationally accepted safety standards, but methods used to estimate extreme weather and flood risks have changed significantly since some were built.

      “This is one of several important dam safety projects being undertaken by Seqwater. Since 2015, Kinchant Dam, Eungella Dam, Wappa Dam, Boondooma Dam, Leslie Harrison Dam, Fairbairn Dam, and Sideling Creek Dam (Lake Kurwongbah) have been completed across Queensland.

      “With construction starting soon, the upgrade is also set to boost local employment opportunities in the region, with around 150 jobs expected to be created over the life of the project.” 

      Quotes attributable to Seqwater CEO, Neil Brennan:

      “While Lake Macdonald Dam continues to operate safely, the upgrade will ensure the dam meets updated engineering and safety standards, taking into account extremely rare weather scenarios and climate change.

      “The revised design will allow water to be retained in Lake Macdonald during construction, some recreation activities to remain open, reduced impact on aquatic life, plants and animals in and around the lake, and will ensure the Noosa Water Treatment Plant continues to operate for local water supply. 

      “Projects of this scale are complex and require significant planning time and we thank the community for their understanding while we undertook this important work.” 

      Further Information:

      Through its Dam Improvement Program, Seqwater is investing in South East Queensland’s dams to ensure they provide water security for years to come.

      Dams are long-life assets which require continual assessment, monitoring and maintenance. 

      Seqwater’s dam infrastructure upgrades are progressively being delivered and are due for completion by 2035.

      Seqwater undertakes regular monitoring and engineering assessment to make sure the region’s dams continue to operate safely.

      An aerial image showing a wide spillway with additional concrete zig zag steps to one side

      Lake Macdonald Dam Improvement Project Update

      Throughout 2021 and 2022, Seqwater worked with a Technical Review Panel to evaluate and short-list options for the Lake Macdonald Dam Improvement Project.  

      In 2023, Seqwater worked to confirm the preferred design option and obtain the required state and federal approvals to proceed with the project. 

      Seqwater has completed comprehensive engineering, environmental and economic studies; as well as taken on the feedback from the previously established community reference group in 2019. All of this information has gone into informing the best design approach that focuses on reducing potential project impacts to the community and environment.   

      Seqwater finalised the design option in late 2023 which involves a new split-level concrete spillway, with an upper labyrinth spillway for extreme floods (see design section for detail).  

      While this is an important project to ensure the ongoing safety of the structure during extreme weather events, Seqwater is committed to avoiding or reducing the impacts of construction wherever possible.  

      Areas of impact assessed included, but were not limited to, water security and the lake level, traffic, noise, dust, water quality, recreation, cultural heritage, and ecology. Seqwater has also taken onboard community feedback obtained through the previous Community Reference Group sessions, where possible. 

      Project planning has included the modification of the construction methodology, and there will now be:  

      • The use of a coffer dam, to retain water throughout the project 
      • More water in Lake Macdonald during construction 
      • The Water Treatment Plant will continue to operate, utilising water from the lake 
      • Environmental flows will be maintained as per the condition of the water license  
      • Reduced impact/risk to aquatic life, plants and animals in and around the lake  
      • Recreation areas at Lake Macdonald Park will remain open during construction:  
      • The boat ramp at Lake Macdonald Park, next to the Noosa Botanic Gardens 
      • Fishing, stand up paddle boarding, canoeing  
      • Benefits to local community and visitors by keeping the lake open 
      • The project will employ local contractors and procure local businesses where possible. 
    • No FAQs match your query

      What is the Dam Improvement Program (DIP)? 

      South East Queensland dams were built to high safety standards, but most were built some decades ago. Methodologies and data used to estimate extreme rainfall events continue to improve and industry engineering standards and understanding of risks can progress over time. 

      Across Queensland and Australia, there are multiple dam upgrades occurring to meet modern engineering standards. 

      Seqwater’s Dam Improvement Program is ensuring the region’s dams comply with the latest safety standards and continue to function safely during extreme weather events in line with regulatory requirements.  

      Since 2008, Seqwater has delivered 13 upgrades, including Leslie Harrison Dam at Capalaba, Sideling Creek Dam north of Brisbane and Ewen Maddock Dam on the Sunshine Coast.  

      Planning work is underway for the next tranche of upgrades at Somerset, Wivenhoe and North Pine dams. Lake Macdonald Dam site establishment works are underway.

      Seqwater undertakes regular monitoring and engineering assessment to make sure the region’s dams continue to operate safely. 

      Why does Lake Macdonald Dam need to be upgraded?

      Lake Macdonald – also known as Six Mile Creek Dam – was originally constructed in 1965. 

      There have been significant advances in dam design since the dam was built, as well as new ways of estimating extreme rainfall and flood events, and a greater understanding of the size and severity of earthquakes.

      This will be the first major upgrade of the dam since the wall was raised in 1980. The Lake Macdonald Dam Improvement Project aims to:

      •    increase the spillway capacity to safely pass floods 
      •    protect the dam wall in extreme flood events
      •    efficiently control water flowing out of the dam 
      •    reduce risks to the dam structure during earthquakes
      •    meet modern design and engineering standards
      •    comply with dam safety guidelines.

      What will Lake Macdonald Dam look like, following the upgrade? 

      The new dam will occupy the same footprint as the current structure, but the spillway will be a split-level concrete spillway. The primary ‘ogee’ spillway is set at the original lake level, and an upper labyrinth spillway will be constructed for large floods. No spillway gates are included in the new structure; and the earth embankments will be reconstructed to their original level on either side of the primary spillway. 

      The primary spillway is a flat concrete structure, similar to the current dam wall.   

      The labyrinth spillway has a zigzag shape when viewed from above and is made from concrete. In the event of a very large inflow, the water will flow over the upper labyrinth spillway and into Six Mile Creek downstream.  

      The current earth fill embankment on the Lake Macdonald Drive side of the spillway does not meet today’s design and safety standards – that is, it is too steep and at risk of erosion. The new embankment at this location will be the same size and height of the existing embankment and finished grass and rocks.  

      The right earth embankment on the other side of the dam's spillway, closest to the water treatment plant, will also be re-constructed and finished with grass (looking much the same as it does now).   

      Rocks will be placed downstream of the new spillway, called scour protection, and will assist in preventing erosion.  

      An outlet tower will be constructed to the left side of the spillway which will have mechanical pipework and electrical components to facilitate both emergency release of water, to lower the dam reservoir, and environmental flows to the downstream Six Mile Creek.  

      What will the cofferdam look like? 

      A temporary cofferdam structure is, engineered to manage inflows after each rain event. This structure will hold back the water in Lake Macdonald during construction of the new dam wall. This is a temporary measure for dam safety and once the new dam wall is complete, the cofferdam will be removed, and Lake Macdonald Dam will be able to naturally refill to its original full supply level.  

      How long will the dam upgrade take? 

      We expect the project to take around five years to complete, subject to weather and construction conditions.  

      How will impacts to the natural flora and fauna be mitigated? 

      As part of the planning and delivery, Seqwater has undertaken extensive environmental investigations by way of both desktop searches and field surveys focusing on protected plants, important habitats for plants and animals, waterway environments, and significant local species. 

      This has helped to inform reduced water levels, locations to avoid around Lake Macdonald, where possible, as well as inform any mitigations needed to be in place during construction. 

      Lake lowering and construction works will have some impacts on the flora and fauna, both in and around the lake, and Seqwater is committed to minimising and mitigating these impacts. A range of surveys and studies have been completed to identify the species of aquatic fauna, including those of conservation significance in the lake. An environmental management plan will be in place during construction, which outlines the measures required to minimise the impact of the natural environment.  

      Click here for the link to the Coordinator-General’s evaluation reports on this project.

      Will there be fish relocation in the lead up to construction?  

      Investigations are underway into the measures needed to manage aquatic fauna at the 42% or 93m reduced water level. Seqwater will develop a recovery and relocation plan, in consultation with key stakeholders, to manage any aquatic fauna impacted during the lowering and throughout construction. 

      It is expected there will be a period when the habitat available for aquatic species, including those of conservation significance such as the Mary River cod, Australian lungfish, Mary River turtle, white-throated snapping turtle, and platypus, is limited. To minimise the impacts to these important species, Seqwater is proposing an initial aquatic fauna relocation program.  

      We will aim to relocate species of conservation significance before construction begins. Some fish are sensitive to handling or changes in water temperature and may suffer injury or mortality if relocated. Therefore, appropriate measures will need to be identified and incorporated into the management approach. 

      All relocation will be delivered by expert fish biologists, via a purpose-built fish transport vehicle to Cooloolabin Dam.

      Can I still fish in the lake throughout the project? 

      Lake Macdonald is expected to remain open to all on-water recreation activities during the construction period including motorless boating, canoeing, and fishing. These activities will be permitted outside of the construction zone, which the cofferdam will isolate. We expect there will be areas around the lake for shoreline fishing. Once the upgrade is complete, Lake Macdonald will continue to be used for water supply as part of the SEQ Water Grid, and the lake will remain open to the public for shared recreation.  

      What will traffic impacts be? 

      Heavy vehicles will use Elm Street and Lake Macdonald Drive. A traffic management plan will be implemented, including traffic control as required to manage the safe flow of traffic, on the affected roads. More information on project impacts, including traffic, noise and vibration, will be provided prior to construction commencing. 

      Will any roads close during construction?  

      During construction there may be partial road closures and temporary changes to traffic conditions at times for the safety of road users. We will provide advance notification of any road closures, including details of any detours. 

      What noise impacts can be expected during construction?   

      The project team will be in contact with residents who are directly affected throughout the project to advise of noise impacts in advance. Every effort will be made to minimise impacts on the local community and environment while this work is undertaken. We thank the community in advance for your patience and understanding while these necessary works are carried out. 

      Construction activities will include, but are not limited to, demolition works, heavy vehicle movement, concrete batching and pouring, rock breaking, drilling, piling, excavation and stockpiling of raw materials. 

      There will be times of weekend and nightworks for time critical construction activities, which we will be sure to notify the local community in advance.

      What impacts will there be to recreation areas?  

      Seqwater has been able to work through a new construction approach and Lake Macdonald is expected to remain open to on-water recreation, and parks and facilities recreation throughout the project. This means that both Lake Macdonald and Lake Macdonald Park (off Lake Macdonald Drive), and the Noosa Botanic Gardens will remain open.

      There will be closures to the scouts campground, the Mary River Cod Park and the Mary River Cod Park boat ramp, the fishing platform on Lake Macdonald Drive, and walking, riding and horse trails.

       

      Will the project construction impact local water security for the region? 

      To maintain local water security during the construction of the project, a minimum Full Supply Volume of 42% will be retained for Lake Macdonald Dam (which equates to a level of 93m AHD), and the Noosa Water Treatment Plant will continue to operate. 

      To the community, this will look approximately two (2) metres lower than the dam's full supply level. 

      This is the level the lake will sit at throughout construction unless dry conditions create a naturally lower level.

      Does the need for a dam improvement project mean the dam is currently unsafe?  

      All Seqwater dams within the Dam Improvement Program continue to operate safely. Dam improvements are undertaken to meet modern guidelines for these life-long assets – many of which were built some years ago. 

      Seqwater undertakes regular monitoring and engineering assessments to ensure all our dams continue to operate safely. 

      Dams in Queensland were built to high, internationally accepted safety standards. However, the methodologies and data used to estimate extreme weather events and flooding impacts have significantly improved, and engineering standards and risks have progressed. 

      All these factors are considered as part of Seqwater’s Dam Improvement Program so our dams continue to operate as they should, now and into the future.

      Will water still be able to flow/runoff downstream into Six Mile Creek?

      In line with the water license for Six Mile Creek, Seqwater manages continuous environmental releases from Lake Macdonald to maintain a healthy water supply to help protect the habitat downstream.

      Environmental releases, which will continue during the project, are adjusted based on a range of factors including rainfall, inflows, losses and releases to ensure we meet our release obligation.

      Seqwater has ongoing long-term source water protection partnership programs with both the Mary River Catchment Coordinating Committee (MRCCC) and the Noosa District Landcare Group (NDLG). As part of these partnerships, Seqwater works with MRCCC and NDLG to improve water quality and broader catchment health.

      Seqwater will continue taking steps to improve overall catchment resilience in the region for water supply and quality benefit, including during periods of low rainfall.  

      Will platypus at Lake Macdonald be impacted?

      Seqwater is committed to the responsible management of the environment, including caring for flora and fauna and complying with relevant legislation and environmental requirements. A Species Management Plan has been developed which addresses platypus preservation, including specific mitigation and management actions for each phase of the project. Measures include riparian vegetation management and considering the timing and volume of water releases to maintain flows in line with the natural creek flow regime for platypuses living downstream.

      Will a fish ladder be included in the upgrade?

      There is no existing fish passage (a fish ladder is a specific type of fish passage) at Lake Macdonald Dam, and no proposed fish passage included in the Lake Macdonald Dam Improvement Project. The reasons for this are:   

      •  A fish passage could allow for pest species such as Tilapia to enter Lake Macdonald reservoir.  

      • A more suitable location for a fish passage has been identified at the Gympie Weir. A fish passage in this location will allow fish to pass up and down the main Mary River, allowing passage between the upper tributaries and reaches. 

      • The Coordinator-General, as part of the Project Approval Conditions, have stated that Seqwater upgrade the Gympie Weir to include a fish passage.  

      What materials will the coffer dam be constructed from, and how will it be built?

      The coffer dam will be constructed from sheet piles, tie-bars, structural steel members, rock bags, and graded rock fill. Cranes equipped with vibratory and impact hammers will drive the sheet piles into place. The same cranes will be used to install the tie-bars, structural members, and rock bags. Rock fill will be delivered by trucks and positioned using earth-moving equipment.

      Where will the construction materials come from for the coffer dam and how will they be transported?

      John Holland, the construction contractor responsible for sourcing materials from business suppliers and quarries, has not yet determined the specific sources for the construction materials. We will keep the community informed on this matter as it progresses.

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