Impacts on the Environment

Impacts on the environment – Balgowlah


An access road is planned for Balgowlah Golf course, requiring new traffic lights to be installed in the middle of Burnt Bridge Creek Deviation, and at Sydney Rd / Maretimo St. Whilst the government promise to re-build sports fields after construction, the green space will be smaller, golf course gone, and over 400 established trees removed, including a large fig tree approximately 150 years old.

The construction will involve diverting diverting a section of Burnt Bridge Creek, removing the lake, and removing surrounding vegetation and habitat that is a valuable green corridor for animals, birds and aquatic life. Critically endangered plant species growing on the site are the Seaforth Mintbush and Magenta Lilly Pilly, and endangered birds such as the Australasian Bittern and Red Knot also visit the site. Recent sightings of small mammals have included bandicoots and echidnas in the area.


The EIS states that Burnt Bridge Creek is “a vital ecological corridor of regenerated habitat that provides a range of important habitats for a diversity of local flora and fauna”(9). Despite describing the creek as “vital”, the construction and tunnelling activities are projected to reduce the natural water flow of the creek by 79%. This will have a devastating effect on the plants and animals that currently rely on the creek. As part of construction, approximately 400,000 litres of wastewater per day will be discharged into the creek from the site that will run into Queenscliff lagoon.

The site is categorised as flood-prone, and it is unacceptable for any waste water, pollutants or contamination by construction soils to enter the creek system and impact all catchment areas downstream.


The site is also in close proximity to the threatened Grey-Headed Flying Fox colony in Balgowlah, and any disturbance by construction noise, destruction of significant numbers of trees they feed on, or polluted sediment in the creek system poses a severe risk to these threatened animals.

The EIS has summised that, whilst only 120 metres from the construction footprint,  the flying fox colony is within an urban environment so an “increase in noise and vibration is not expected to have a significant impact”(3). This is despite predicted noise levels exceeding 75dB(A) and the awakening reaction level for people at nearby residences, particularly during night roadworks.

An expert in flying fox behaviour is required to asses the colony periodically during the breeding season, with powers to temporarily stop work if construction causes harm, but the point at which this is triggered is unknown.


The community is concerned with the overall loss of green space, in a region that is already flagged as having insufficient community green space. As it is public land, the golf course is not just used by golfers; it has a popular shared walkway/cycleway alongside the course, and the course itself is used by many residents for exercising their dogs or walking on a daily basis. More sports fields are needed on the Northern Beaches, but they are needed further north in larger population centres, not in the Balgowlah region where we are well served by Tania and Kierle Parks, Seaforth Oval, and Nolans, Millers, David Thomas and Passmore Reserves.

The NSW government claims that 90% of the site will be returned after construction as public green space, however this is only achieved by the acquisition of 34 homes on Dudley St, and the community questions how usable this green space will be next to large roads and an unfiltered exhaust stack.


Sections of Burnt Bridge Creek and Balgowlah golf course that will be destroyed with the planned tunnel

Impacts on the environment – Seaforth and Manly Dam

Construction is planned to widen the full length of the Wakehurst Parkway from Warringah Rd to 4 lanes, and a tunnelling site near Kirkwood St, Seaforth. This area covers a section of the Duffys Forest Ecological Community, a site with many highly endangered plant species, and a type of native bushland that is near extinct due to land clearing, development and weed infestation(1).

The EIS reveals that 1979 mature trees will be removed in Garigal National Park / Bantry Bay and Manly Dam Reserve(5) with replacement planting for only 339(6), replacing mature trees with only young saplings.


The site is also within the Manly Dam Catchment zone. Many years of construction run-off is a significant risk to the creeks and riparian zones near waterways that flow into Manly Dam, into Burnt Bridge Creek and into Manly Lagoon, a catchment already under considerable strain.


Fauna assessed in the area include numerous threatened species – including the Eastern Pygmy-possum, Powerful Owl, Rosenberg’s Goanna, Large-eared Pied Bat, Grey-headed Flying-fox, Red-crowned Toadlet, and the rare Galaxias brevipinnis, a climbing fish that is unchanged by evolution since the Gondwana era 60 million years ago.

The EIS states “Fauna can be sensitive to elevated noise, changing their behaviour and impacting their physiology… Fauna may initially desert the immediate area at the start of excavation activities due to increased noise and vibration levels… However, due to the extent of adjoining habitat, the initial displacement from the immediate area could become permanent. For less mobile species or breeding individuals, the effects of the high noise levels may be more acute.”(4).

In other words, more mobile species would most likely stay away from the area – but the assumption that there is plenty of surrounding bushland without competiton for territory or resources with other animals is contentious. It is also an injustice that less mobile and breeding animals unable to move are left to suffer destruction of habitat, noise, vibration, lighting at night, dust and potentially contaminated run-off water.

Eastern pygmy-possum and Grey-headed flying fox


Also impacted by the construction at Seaforth are numerous ancient Aboriginal rock carvings and middens. A government blueprint warned that the tunnel project would lead to some destruction that “cannot be avoided” and that “it will be difficult to justify major impacts” to the sites of high cultural significance to indigenous people. At these sites, the blueprint suggests excavating and removing the objects – an option unacceptable to indigenous leaders(2).

The EIS states “The Wakehurst Parkway landscape region is particularly significant because of the Hawkesbury Sandstone and its association with known Aboriginal rock engravings”(7). Within 50 metres of the footprint of the project, there are 11 sites of Aboriginal cultural heritage including rock art, engravings and rock shelters that are vulnerable to vibration impacts.


The reason these areas have not been developed in the past is because we used to value our natural and indigenous heritage, and protect endangered flora and fauna – do we still value these things?


A video produced by Save Manly Dam Bushland, shows the full extent of what is at risk by the tunnel project.

It can be viewed here:


Impacts on the environment – Middle Harbour


Construction in Middle Harbour involves the construction of 2 cofferdams, and laying immersed tunnel tubes either into the sediment or on small stilts on the harbour bed (dependent upon depth).

There is significant risk to the marine environment from disturbance of sediment, increased turbidity and potential fuel/oil leaks and spills during construction. Sediment samples revealed levels above safe guidelines of heavy metals, mercury, lead and pesticides(8). If released during dredging, these would have devastating impacts upon the seagrass, aquatic life including endangered marine species such as the White’s seahorse, and people enjoying swimming, boating and fishing in the surrounding areas of the Spit, Clontarf, Beauty Point and Sailors Bay.

1) NSW Office of Environment & Heritage – Duffys Forest Ecological Community Final Determination

2) Beaches Link tollway construction threatens to destroy ancient aboriginal rock art (ABC news, December 17, 2018)

3) Beaches Link EIS, Chapter 19 Biodiversity, page 63
4) Beaches Link EIS, Chapter 19 Biodiversity, page 64

5) Beaches Link EIS, Appendix W Arboricultural impact assessment – Part 1, page 16
6) Beaches Link EIS, Appendix W Arboricultural impact assessment – Part 1, page 24

7) Beaches Link EIS, Chapter 15 Aboriginal Cultural Heritage, page 7

8) Beaches Link EIS, Appendix Q Marine Water Quality, page 51

9) Beaches Link EIS, Appendix O, page 45