Digging a Hole in the Harbour !

A proposed new harbour crossing included in the WestConnex plans differs from the usual method of using boring machines to work underground to bring it to fruition.   This crossing will take the form of a trench dug in the sea floor under the harbour and the tunnel casing constructed on shore and later lowered into that trench.

The tentative plans call for it to extend from the WestConnex at Rozelle to the Warringah  freeway at North Sydney and so far there have been 1450 submissions lodged against it.  The objections relate to both the placement of ventilation stacks and their proximity to schools and houses and the handling of highly contaminated spoil from that trench excavation.

The plans call for most of the spoil excavated for this tunnel to be  dumped at sea but the 142,500 cubic metres from the top layer of the sea bed will have to be treated onshore before it is carted away to landfills.  It is proposed that this be carried out at White Bay, just 150 metres from existing housing and apartments.

This is an entirely new method of tunnel construction and the extent of the harbour floor penetration is not yet determined.  There is no clarity in the purification methods to be used nor is the type of contamination fully known.  There is a danger that even with adequate regulations and the best intentions  there is a chance of an unforeseen spill or accidental event.

Nearby residents contend that they bought their houses and apartments in good faith, with no warning from the state government about " such adverse impacts ".   Even with good luck preventing accidents they will have to live for a period of time with an unsightly vista and unpleasant odours which will impact on dwelling prices.

Then there is the issue of those ventilation stacks.  Concern has arisen about Glyphosate which is an ingredient in the weed killer - Roundup, and some scientists have suggested that this could be the trigger for autism.  It seems that Glyphosate is small quantities in also added to car fuel and it could be dispersed wherever these ventilation stacks are located.  If this contention is correct it will certainly compound objections to stack placement.

When construction methods change it is always a trip into the unknown.  It is inevitable that some of this spoil will be dispersed in the harbour and the quantity involved will necessitate major truck movements taking it to landfill.  The government will need to lay out the process in fine detail
 if it hopes to convince residents of its safety  !