Petition to the Legislative Assembly of NSW – please stop mining under Woronora Dam

In-principle approval for at least 10 longwall mines which are expected to pass below Woronora Reservoir has been granted.

Rob Stokes, the Minister for Planning and Public Spaces, is currently considering whether to grant final approval for several of these to go ahead. We have been advised the decision is likely to be made early in 2020. Two of the mines under consideration, LW306 and 307, will run directly under Wororona Reservoir.

Whatever your political leanings or position on coal we believe this is a matter that goes beyond politics. Our water supply is simply too important to compromise.

The Woronora ‘Special Area’ catchment delivers a significant proportion of the Sutherland Shire’s drinking water. Over the last few months Sutherland Shire Environment Centre has been collecting a petition in hard copy paper format – petitions with over 10,000 signatures can be presented for debate in the NSW Parliament. Maintaining the integrity of our water supply is important – and should be given public consideration.

In February 2020 we submitted the petition with 10,690 signatures to state parliament. The matter has now been set down for debate on 26 March 2020.

Despite the petition, public sentiment has not registered with many of the politicians who will be making decisions about whether to protect our water. Many seem more concerned about how this reflects on their party’s overall position on coal. Telling them it’s about water not coal doesn’t make a difference.

So many people we’ve spoken to are appalled at what is taking place. Mining under a major water supply makes no sense. A recent freedom of information request found Cataract and Cordeaux dams breached recommended iron levels 90 times in three years due to mining related activity. We do not want that to happen to Woronora.

We are now asking everyone concerned about this issue for your help – even a short email to your local State MPs – this may be the one that makes a difference. Please ask them to protect our water in the coming debate, and to encourage other members of parliament to step up and take a stance. We have included some contact emails for them at the bottom of this page.

The photo to the left here is of the Eastern Tributary of the Waratah Rivulet. It was taken in July 2019, and shows heavy iron oxidising bacteria growth and iron oxyhydroxide floc contamination.

This water all runs directly toward Woronora dam.

Water in this area is supposed to be pristine, and the water clean, filtered through natural streams and swamps – the water has changed to this rust colour because it drained underground through cracks caused by subsidence from longwall mining, and has come out again contaminated.


The Woronora Dam catchment is classified as a ‘Special Area’ – permission is required to enter. Fines for entering without permission can be up to $44,000.

The photos you see on this page were taken on the few occasions permission was granted. People are not normally allowed into the area in case they cause damage, or pollute the water.

Waratah Rivulet is a significant tributary leading to Woronora dam. The photo here shows a streambed that has cracked due to mining related subsidence – compressive forces have caused “upsidence” where the creek bed bulges. All surface flow has been lost.

(image: Julie Sheppard – for more images please see the Protect our Water Alliance website)

Cumulative impacts could have serious negative consequences for reservoir water quality

The Wororona ‘Special Area’ is covered with larger rivulets, streams and swamps.  Swamps play a critical role in filtering and purifying our water.  In the mine plan map here, the swamps are depicted in brown.  A recent independent expert panel looking into mining in the catchment has noted that damage to swamps from mining can be irreversible.  Their Report states mining should not be allowed on the basis that remediating swamps is possible.   

According to WaterNSW at least two swamps in this area have already dried out due to mining related activity. They have said that mining in the Woronora Special Area catchment has resulted in ‘environmental consequences [that] have caused (or are likely to cause) breaches in conditions in the relevant development consents, including performance criteria to protect watercourses and Sydney’s drinking water catchment.’ 

They also say ‘that there are numerous deficiencies in the manner that analysis and modelling is currently being used to support mining applications in the catchment.’

The independent Expert Panel similarly noted predictions of impacts have proven unreliable. Their final report states that water returning to the surface from mine workings can ‘leach metals’ and this ‘needs increased attention in mining proposals, especially in the Special Areas where ‘cumulative impacts could have serious negative consequences for reservoir water quality‘.


Pool N

The video below shows ‘pool N’, which was a 150m long permanent pool of water, part of the Waratah Rivulet that flows into Woronora dam. It remained full during the 2006-7 Millennium drought. This video was taken in 2014 when it drained dry due to cracks in the bedrock.

If the water reemerges from these cracks it can be leached through with chemical contaminants including iron, aluminium and manganese, lithium, strontium, barium, titanium, zinc and nickel. Even trace amounts of zinc and nickel are toxic. Whether such contaminants are accumulating on the floor of the Woronora reservoir is unknown.

The Independent Expert Panel report also states there is a limited understanding of the extent to which water is entering old mine workings, and notes the danger of the ‘permanent diversion of catchment water into mine workings.’ The report states this raises the question of the reliability of estimates of how much water is being diverted from the catchment. 

Further reading –

A recent report with data obtained by the ABC under freedom of information law, has found samples from Cataract and Cordeaux dams have exceeded acceptable limits more than 90 times in three years: ‘Shocking’ metallic sludge contaminating Sydney dams that supply drinking water’.

In late July 2019 The Sydney Morning Herald published an article with drone footage showing streams filled with more red and soupy green discoloured water: ‘Shocking’: Mining damage in Sydney’s catchment prompts calls for halt‘.









Members of parliament to contact and ask for assistance to protect our water –

Lee Evans MP
Mark Speakman
Eleni Petinos MP
Rob Stokes
Matt Kean MP
Melinda Pavey
Jodi McKay MP
Clayton Barr MP, Member for Cessnock
Kate Washington MP
Mark Buttigieg MLC
Ryan Park for Keira
Jamie Parker MP


Independent Expert Panel for Mining in the Catchment Submissions and Reports

The final recommendations in this report suggest mining in Woronora be allowed to continue subject to increased monitoring.   The original terms of reference for this review focused on identifying how to “strengthen monitoring networks”, and “undertaking further scientific research” – the terms of reference ensured the report focused on monitoring, rather than the question of whether mining should be allowed at all. This made the final recommendations a foregone conclusion.

We do not view continued mining with increased monitoring of increasing damage as a solution.  Mining induced subsidence can continue even 20 years after it initially occurs – the damage is ongoing, and will get worse over time, even after the mining company has left.


The Water NSW Act 2014 states WaterNSW has a statutory obligation ‘to protect and enhance the quality and quantity of water in declared catchment areas’.

The Woronora Special Area catchment is a critical public asset, part of our water supply infrastructure.  The Act also requires WaterNSW to act ‘in accordance with sound commercial principles’, and ‘to maximise the net worth of the State’s investment’.

Our water supply ‘Special Area’ catchments were set up originally so that if one failed the others could stand in as reserves.  In 1998, extreme rain and flooding filled the drought-affected Warragamba Dam in just a few days. This triggered the Cryptosporidium crisis.  Woronora was not affected.  In 2015 the desalination plant was damaged by a typhoon and took a few years to properly repair.

Our ‘Special area’ catchments are meant to be protected for a reason.


Image: Julie Sheppard –

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