On 3 January 2020 Penrith was the hottest place on earth recording a temperature of 48.9 degrees at 3pm. Those who live in this area rely on air-conditioning and shopping malls to stay cool when temperatures become unbearable. There is minimal tree cover to cool the environment. Tree loss is continuing at an unabated rate to make way for more homes to deal with NSW's population pressures and to expand roads to deal with traffic congestion. This is not hyperbole but reality. One needs to look no further than the Oran Park development and the planned expansion of Mulgoa Road near the M4 intersection to find the necessary proof.

The NSW Government's proposal to raise the Warragamba Dam wall in direct response to these pressures is unforgivable. It is wilfully disregarding its international responsibility to protect the unique culturally and ecologically rich Greater Blue Mountains World Heritage Area from the significant threat urban expansion poses.

A decision to proceed with the raising of the dam wall will put at risk over 1,500 identified First Nations’ cultural heritage sites and wilderness areas valued by all Australians and international visitors. It will result in the inundation of 65 kilometres of declared wilderness rivers and 1,300 hectares of National Parks within the WHA and another 4,400 hectares in National Parks outside the WHA. The richly diverse eucalypt forests that give the Greater Blue Mountains WHA its Outstanding Universal Value will be threatened including the already endangered Grassy Box woodlands and the Camden White Gum. The critically endangered Regent Honey Eater and Sydney's last Emu population may be driven to local extinction.

The EIS is fundamentally flawed. It fails to consider the impact of the devastating 2019/20 summer fires. Threatened species surveys do not meet guideline requirements. Alternative flood risk mitigation strategies are not comprehensively assessed and there is no modelling of the stated flood and economic benefits of the dam wall raising contained in the EIS.

The proposal to raise the dam wall is being progressed without the free, prior and informed consent of the Gundungurra Traditional Owners. The Aboriginal Cultural Heritage Report (part of the EIS) is subject of serious criticism by the Commonwealth Department of the Environment and International Council on Monuments and Sites. Only 27% of the impact area was assessed for Aboriginal Cultural Heritage.

With on average 45% of floodwaters being sourced from areas outside upstream of the Warragamba Dam catchment, no matter how high the dam wall is constructed it will not prevent flooding in the Hawkesbury-Nepean Valley. Further housing development downstream of the dam wall will exacerbate flooding due to increased storm water run-off from paving and roads.

Rather than raising the dam wall, the NSW Government should end development on the Cumberland flood plain while also returning existing housing and commercial areas to farmland. This approach, supported by the Insurance Council of Australia, has been adopted successfully in the Netherlands and there is no reason it couldn't and shouldn’t happen in the case of Western Sydney.

I oppose the raising of the Warragamba Dam wall.

I oppose the dam raising because of its impact on world heritage listed areas and the Regent Honeyeater)! THE EXTINCTION RATES IN AUSTRALIA ARE ALREADY HISTORICALLY BAD - AND ABOUT TO GET MUCH WORSE. DO YOU REALLY WANT OUR FLORA AND FAUNA TO DISAPPEAR FOREVER - BECAUSE AT THE MOMENT AUSTRALIA HAS ONE OF THE HIGHEST EXTINCTION RATES IN THE WORLD.

To whom it may concern,
Think beyond short term goals.. do not ruin this world heritage area for everyone, animals and plants included.

To whom it may concern
As a long-term resident of Greater Western Sydney and a concerned citizen of NSW, I strongly object to the proposal to raise the Warragamba Dam wall. I believe this is an ill-considered plan which will do enormous damage, without providing the posited advantages.

First and foremost, the proposal does not have the approval of the traditional custodians, the Gundungurra people. This should actually be the end of the story! No doubt the custodians were horrified to learn more than 1500 cultural heritage sites would be inundated, and thus damaged or lost, were the wall to be raised (and that’s just the number of sites identified to date, with reportedly only 27% of the impacted area assessed for cultural heritage). I understand the relevant Aboriginal Cultural Heritage Assessment Report has been criticised by the Australian Department of Environment and the International Council on Monuments and Sites due to its inadequacies. Unless the traditional custodians have been fully involved and informed, the whole area has been assessed, and the custodians have agreed, the proposal should not proceed.

Evidence provided to the recent NSW Parliamentary Inquiry into the wall-raising proposal uncovered serious concerns about the integrity and accuracy of the Environmental Impact Statement (EIS) prepared on behalf of Water NSW. Expert ecologists’ advice on adverse impacts was minimised and/or selectively edited, with one resigning rather than have her name included in the statement. Threatened species surveys did not comply with guideline requirements. Some field surveys did not even include expert reports. And seemingly there was no modelling of the stated flood and economic benefits. At the same time, alternative options were not fully assessed.

The environmental and ecological damage caused by raising the wall would be significant, with many hectares of national parks and kilometres of wilderness rivers affected. “Threatened Ecological Communities” and “Critically Endangered Species” would be severely impacted. The beautiful Regent Honeyeater, of which there may only be around 350 in the wild, would lose foraging and breeding habitat. Sydney’s last emu population could also be at risk. Although so much of the Blue Mountains flora was destroyed in the 2019-20 bushfires, I gather there have been no field surveys since, which is a clear lack.

Given that around a quarter of affected area is within the Greater Blue Mountains World Heritage area makes it even more important to protect it, rather than destroy and damage parts of it for nebulous benefit. The area, with its unique eucalypts and rare and threatened flora and fauna, has been internationally acknowledged as a treasure and this should be respected. Of course, it is also a major tourist attraction, with all the attendant benefits of that.

In addition to the traditional custodians, multiple experts and numerous organisations have expressed grave reservations or opposition to the proposal, including for example Heritage NSW, the Insurance Council of Australia, the UNESCO World Heritage Committee, the National Parks Association of NSW, the Colong Foundation and local councils. The chair of the Parliamentary Inquiry Committee Justin Field wrote: “It is unequivocal that the project will have significant, if not devastating, impacts on upstream biodiversity, including on critically endangered species like the Regent Honeyeater and pristine wild rivers like the Kowmung” (reported in the Sydney Morning Herald, 5/10/21). Once this is done, it cannot be undone.

Of course, no one wants towns and suburbs to be flooded either. It would’ve been better if housing and other developments hadn’t been put in a flood-prone areas in the first place. (And certainly, more should not be allowed.) But raising the dam wall will not mitigate the risk. I understand that nearly half of the floodwaters potentially affecting the Hawkesbury-Nepean Valley would come from upstream of the dam. And during or after major rain events, the dam could still flood anyway. Even Liberal and National Party members of the Parliamentary Committee have supported examination of alternative flood mitigation options (also reported in the Herald article quoted above).

No doubt, many expert submissions will be made addressing the problems with the wall-raising proposal and the EIS in greater detail. Public opposition to the proposal is gaining momentum as its implications become more widely known. It would be better not to raise the wall, and I hope intelligence will prevail in that regard.

Yours sincerely
Anne McLean
15 December 2021

Warragamba Dam Wall Raising


I wish to register my objections to the proposed raising of the Warragamba Dam wall.

My primary reason for objecting is the impact on the Greater Blue Mountains World Heritage Area, in particular the wilderness area of the Kowmung River. Any damage to this area is akin to destroying Lake Pedder in Tasmania or the Juukan Gorge caves.

I am also concerned about the taxpayer funding for the flood mitigation works will just serve to benefit downstream landowners and developers. Any financial benefits from the scheme should flow back to taxpayers.

The Need for Dam Wall Raising

Warragamba Dam was built for potable water capture and storage. Although the construction of the dam caused significant environmental impacts at that time, the need for a water supply for Sydney and the technology available at that time led to the current existing dam.

The proposal to raise the dam level to use the augmented storage for flood retention and prevention of downstream flooding will cause significant further impacts.

I understand that there is no need for structural works on the dam to ensure dam safety.

I understand that there is currently no intention of using the augment dam capacity for addition water storage for Sydney’s water supply.

The entire rationale for the dam raising of the dam is to reduce flooding of downstream areas. It is noted that much of the flooding comes from other than the Warragamba catchment.

Environmental Impacts

When any development is proposed, the environmental impacts must be considered.

The principles of dealing with impacts are:-

1. avoid the impacts
2. unavoidable impacts should be mitigated
3. offset impacts

To avoid the impacts on the upstream areas, the raising of the Warragamba wall should not proceed. This would mean that properties and infrastructure downstream would still be subject to flooding. Since most of these works should not have been built in the first place (going back to Governor Macquarie), I have no problems with this. I suspect, however, that the political imperatives will govern, and the works on the dam wall raising will proceed.

Consideration must therefore be given to the mitigation of the impacts.


Mitigation of Impacts on Wilderness Areas (Kowmung River)

Vegetation permanently inundated will eventually die. The proposal is to only use the additional dam storage as a temporary measure, so with proper management the native vegetation should be able to be saved, especially for those areas inundated in the most extreme events.

Key areas of the wilderness areas should be given remedial works after any flooding event. This would certainly be for any parts of the Kowmung River that may be flooded, and possibly the Cox’s River. Any areas that become damaged by flooding must be reinstated by planting appropriate native vegetation, and any exotic weed species that are likely to establish in cleared and vulnerable flood affected areas must be eliminated.

There are a number of National Park, Council and Landcare Groups which would be capable of carrying out such remedial works when required. Compared to the capital costs of the scheme, ongoing and infrequent maintenance and regeneration works would be minimal.

The critical areas requiring consideration for ongoing treatment after flooding must be identified prior to completion of any wall raising works. A number of creeks and rivers feeding into the dam should be so treated, though the Kowmung River would be considered the most important.

Ensuring no loss of existing vegetation will minimize erosion problems and subsequent increase of sediment within the dam.

Additional offsets to (e.g. extra land added to National Parks) have been proposed, and these should still proceed, as even with remedial works after flooding, the overall loss of vegetation could be significant.


Mitigation of Impacts on Indigenous Heritage

I am not an expert in these matters, but I understand that there could be significant sites within the affected areas.

Before any works commence there must be a complete survey of the entire affected area. Any resulting action can be determined at that time, but we can not allow destruction or damage without a full understanding of what is likely to be affected.


Floodplain Development

The proposal to raise Warragamba Dam wall is to protect downstream infrastructure in the floodplain, particularly around Windsor and Richmond. Current development has occurred over many years, guided by a variety of (generally inadequate) rules on flooding likelihood and flood levels. This has resulted in much development that should not have occurred, but has meant some people with vulnerable properties were unaware of the extent of the risks. I therefore do understand the aims of the Government to resolve these issues.

Currently undeveloped land within the floodplain should not be developed as a result of mitigation works resulting from the Warragamba Dam raising. Any beneficial gains from development of land, which is currently unsuitable because of potential flooding, should flow to the government of NSW. Ideally, any additional land could be used as recreational land (including national parks) to further offset upstream losses and to provide additional recreational land in an area of Sydney which is rapidly expanding and losing such areas.


Summary

Ideally, no raising of the dam wall.

If dam wall is raised:-

• Never use the additional dam capacity for permanent water storage.

• Provide addition areas of National Parks as offsets

• Carry out rehabilitation works in critical upstream areas after each flooding event.

• Carry out a full investigation of all impacts on indigenous heritage

• Carry out no further development in current flood prone areas



Geoff Bowmaker

To whom it may concern,
I do not agree with the raising of the Warragamba Dam wall. I do not want to see any more threatened species or indigenous sites destroyed as a result of an inadequate, floored and misleading EIS. Please do not do this.

To whom it may concern,
I am very worried about the effect this dam will have on the World Heritage listing and cultural sites.
I also worry about builing more reidences on a known flood plain.
No matter how high the dam wall is constructed, it will not be able to prevent flooding in the Hawkesbury-Nepean Valley downstream.

To whom it may concern,
I fail to see the point of raising the dam wall as a flood mitigation measure, apparently it would have dellayed toe onset of the recent Hawkesbury floods by about 12 hours, and that delay is of no use to anyone, and is not worth destroying the Greater Blue Mountains World Heritage Area for such an insignificant delay.
Further, as an engineer, I an greatly concerned at the ability of a dam built in 1960 and increased in height in 2006 to take an additional 17 metres without endangering the security of the dam.
This whole proposal appears to be anti environment. amto First Australian and will only appraise Hawkesburt Valley developers.