Raising Clarrie Hall Dam

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Council is undertaking a number of related projects to secure a long-term water supply for the growing shire and adapt to the impacts of climate change. One of those projects is the raising of Clarrie Hall Dam.

In December 2015 Council resolved to undertake the planning and land acquisition for the raising of Clarrie Hall Dam. It is proposed to raise the wall of Clarrie Hall Dam by 8.5 metres to a height of 70 metres Australian Height Datum (AHD RL70) thereby increasing the size of the dam from 16,000 megalitres (ML) to approximately 42,300 ML to provide a secure

Council is undertaking a number of related projects to secure a long-term water supply for the growing shire and adapt to the impacts of climate change. One of those projects is the raising of Clarrie Hall Dam.

In December 2015 Council resolved to undertake the planning and land acquisition for the raising of Clarrie Hall Dam. It is proposed to raise the wall of Clarrie Hall Dam by 8.5 metres to a height of 70 metres Australian Height Datum (AHD RL70) thereby increasing the size of the dam from 16,000 megalitres (ML) to approximately 42,300 ML to provide a secure water supply for the Tweed until at least 2046.

An Environmental Impact Statement for the project is being undertaken by consultants Eco Logical Australia.

The EIS is expected to be completed by March 2021 and will be placed on exhibition for public comment.

EIS sub-consultant The Comms Team will engage with the community in February to help interested residents and others understand the EIS. That consultation will occur online on this site.

The online community consultation will be widely advertised and all registered participants of Your Say Tweed will be invited to participate. You can register to Stay Informed by following the link at the top right-hand of this page.

Once the EIS goes on public exhibition, anyone wishing to make a comment or submission on it will be directed to the Department of Planning Industry and Environment (DPIE) website. We will publish a link to that site here.

Context

Council is undertaking a number of related projects to secure a long-term water supply for the growing shire and adapt to the impacts of climate change.

Through Council’s water-efficiency initiatives, the average Tweed resident has reduced their demand for water by more than 20 per cent in recent decades, allowing Council to service an increasing population without increasing the amount of water drawn from the Tweed River. Currently, Council is able to meet demand for water until approximately 2026.

To service the needs of the community after 2026, Council has resolved to undertake the planning and land acquisitions to raise Clarrie Hall Dam. This raising will treble the dam’s capacity and double its footprint, providing water security until at least 2046.

Further impacts of climate change are sea level rise, lower flows in the Tweed River and a forecast greater frequency of extreme weather events. This creates an increasing risk that Bray Park Weir will be overtopped by estuarine waters. That overtopping can result in salt water contamination of the Tweed District Water Supply. To address this risk, Council has resolved to accept the recommendation of a community project reference group to install a hinged barrier on the weir.

The third proposed water security project is to build a pipeline to connect the Tweed with the City of Gold Coast supply in south-east Queensland. The pipeline will provide an alternative water source in the event of a gross failure of the Tweed District Water Supply due to extreme drought or infrastructure failure. This pipeline would not negate the need to raise Clarrie Hall Dam.

To ensure Council’s approach to securing a long-term water supply for the Tweed continues to be appropriate, Council has been working with the community to review all its water strategies; being Demand Management, Water Augmentation and Drought Management Strategy. A report on this work is due to go to Council early in 2021.


Q&A

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    Hi, I’m wondering how the raising of the wall will affect residents downstream for flood insurance? Also what steps are being taken to strengthen the wall so movement doesn’t happen to the extent it has so far?

    Another Concerned resident asked 8 months ago

    There has been no movement of the wall since its construction. 

    The raised dam will be of a similar structural integrity and the raised wall will not move.  The raising of the wall will not increase risk to downstream properties.

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    Why is all of this taking so long? I mean this has been talked about since at least 2016, we are now 4 years on nothing. I am so very concern that DPI still shows that Twedd is in drought, we need our water urgently.

    Mazza asked 6 months ago

    Typically the raising of a dam, from a decision to do it to completion takes about 10 years.  The 10 years comes from requirements to:

    • Undertake preliminary studies to ensure there are no issues preventing the project and identify issues that need to be considered in the concept design (quarry sites, road diversions, land acquisitions etc)
    • Prepare a concept design (flood hydrology, seismic studies, geotechnical investigations etc)
    • Undertake an Environmental Impact Statement in accordance with requirements set out by the State Government
    • When the EIS is complete a detailed design, taking into consideration the conditions of approval, needs to be undertaken
    • After detailed design, tendering and construction
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    Hi, I have been looking at the information provided on potential impacts of this project and wanted to ask if consideration has been given to the increase in prodction of methy mercury from the flooding of vegetation and soils as the water level is raised. This is a signifcant issue in Canada with flooded reservoirs that has led to bioaccumulation of mercury in aquatic species, particularly higher trophic level fish that may be consumed by people. Thank you for your consideration of my question. Regards Charity

    Charity asked almost 2 years ago

    There is no known source of methyl mercury in the catchment of Clarrie Hall Dam.  The soils in the catchment area have never been tested for methyl mercury and it has never been raised as a concern.  Council has referred your question to a number of experts and none of them could provide comment on methyl mercury being an issue.  

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    Obviously I am aware that what I am about to ask here will in no way be a priority for the Council for this project and my expectation is that the answer will be that it is not on the radar at all. But...is there any opportunity here at all to build or allow to be built public use nature trails? What I have in mind here is a trail that skirts the entire circumference of the dam. This area is a fantastic natural resource and I believe it should be made available in ways for the community to enjoy. For example, the Hinze dam just up the road has a number of mountain bike trails that are free to enjoy. Thanks for your time.

    Warwick asked 12 months ago

    Council is to develop a master plan for the catchment lands in Council ownership.  The primary purpose of the catchment is to maintain water quality in the dam.  Notwithstanding there are a range of activities that could be undertaken in the catchment that would not impact on water quality.  These include things like walking trails/nature walks.

    At this stage we are mapping the features within the land Council owns so we can determine how best to develop the catchment to provide amenity and recreational opportunities to the public.

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    why hasn't the new dam been started that the weed Shire bought the land for many years ago we need more water storage in the Tweed our population is rising fast. We have just seen the water shortage devastation so now is the time for that new dam to be built ready for the next drought that will happen and it will.

    ronbar asked about 1 year ago

    In 2009/2010 Council engaged consultants MWH to prepare a series of reports to inform a Community Working Group and assist Council in determining a preferred option for the augmentation of the Tweed District Water Supply.

    In 2014 there were reviews of:

    ·  Secure yields based on 1 degree warming by 2030;

    ·  Demand projections;

    ·  Options; and

    ·  Costs.

    The reviews indicated the need for an augmented water supply by 2026.

    Based on the information available, on 10 December 2015, Council resolved in part:

    1.  Based on the information currently available, Council adopts the raising of the wall of the Clarrie Hall Dam as the preferred option for future water security and proceeds with the planning approval and land acquisitions phase for the project.

    Council has been proceeding with the implementation of this Resolution. 

    Council has now engaged Eco Logical Australia to prepare the Environmental Impact Statement for raising Clarrie Hall Dam.  The EIS is due to be completed by the end of this year.

    Raising Clarrie Hall Dam by 8.5 metres as proposed, the secure yield of the dam will treble, ensuring sufficient water for the Tweed until about 2046.

    The alternative of building a dam at Byrrill Creek would have cost more and would not have provided such longevity.