The Beagle Editor, I was confronted this morning by the unofficial mayor of Dalmeny, Mr. Peter Bernard, with a story about Council’s plan to build a 100-million-dollar dam without any consideration of its own sea level rise policy. Peter apparently raised his concerns in open forum at this week’s council meeting.
I asked Peter if he really believed that a council, leading the pack in sea level rise policy development, would ignore its own sea level rise projections, on a project of this magnitude. He then proceeded to produce a swag of evidence that left me speechless.
An off-stream dam is proposed for the Tuross River between Bodalla and Eurobodalla (see figure 1).
It is planned to pump water from the Tuross River into this storage dam. Peter did not have the elevation of the river bed at the point of pumping, but figure 2, shows that it is only 2.3 kilometres upstream from the current tidal limit.
As a major infrastructure project, Peter believes that Council’s policy requires the dam to have a design life of at least 100 years. With the time needed for approvals, funding, and construction, 2030 is his estimated year for completion. So, by his calculation the dam must be planned to service the Eurobodalla community until the year 2130 or beyond.
Council has formally adopted a sea level rise projection of 1 metre plus from 2100 (see the extract from the ESC Interim sea level rise policy at figure 3).
Peter then concluded that this projection would increase to around 1.3 metres by 2030. I thought this was a fair assessment until Peter produced the latest scientific paper from the NSW Office of Environment and Heritage. That paper, “A regional scale approach to assessing current and potential future exposure to tidal inundation in different types of estuaries” was released in May 2018. It uses NOAA research from the US to support a credible sea level rise prediction of 2 to 2.7 metres by 2100. If this figure is accepted, Council will need to incorporate sea level rise of around 3.5 metres into its Bodalla Dam planning regime.
These latest projections may sound high, but as Peter pointed out, the paper was reviewed by Dr. John Church, a major contributor to the climate change assessment of the Intergovernmental Panel on Climate Change (IPCC), and Professor Bruce Thom, the head of the NSW Coastal Council, and reviewer of the Wharf Road Coastal Zone Management Plan. Who is Peter to dispute the endorsement of a report by these learned gentlemen?
Sea level rise as low as 20 centimetres, which Council expects to be exceeded by 2050, could see them pumping salt water into their new dam, unless a weir is built to prevent the salt water from contaminating the pumping grounds. This scenario introduces another set of environmental problems, but as Peter said, “why build an off-stream dam when you have to build and on-stream dam or weir anyway, to protect your fresh water resource?”
I told Peter that this was not the type of issue in which the NSW Coastal Alliance would normally become involved, but I agreed to write it up in the interests of the general community. We do not need a “dud” 100-million-dollar dam on the ESC assets register.
Ian Hitchcock
Eurobodalla Regional Coordinator
NSW Coastal Alliance
