Ettalong Point recedes seven metres

The beach at Ettalong Point has receded by up to seven metres in the last two years, according to information provided by Gosford Council.

Council's natural open space coordinator Mr Larry Melican claimed last week that this information was unlikely to be useful for the long-term management of the beach.

However, he did concede that Ocean Beach was "much slower" to replenish than "open coastal beaches" because of its position and orientation.

The beach erosion information was collected as part of a study to update the Broken Bay and Open Coast Beaches Coastal Management Plans which will be amalgamated into one plan for all beaches in the Gosford local government area.

Mr Melican said: "While it is interesting to collect this information ... it essentially provides a snapshot of [just part of] a much longer-term beach erosion-accretion cycle."

While listing a range of influences, including swells, storms and the "southern oscillation" cycle, he avoided the mention of "climate change", which is expected to result in more frequent and intense storms and a rise in sea level.

The State Government contributed $150,000 to the study in 2009 amid concerns about the impact of climate change on local beaches.

"Delays [in the preparation of coastal management plans] are no longer an option when storms are becoming more destructive and the CSIRO tells us sea levels will rise by up to 40cm by 2050," the then Minister for Climate Change and the Environment Mr John Robertson said at the time.

Mr Melican told Peninsula News last week: "Sandy beaches are dynamic sedimentary systems that naturally experience phases of erosion and accretion that operate over a range of time intervals.

"All of the Central Coast beaches have been very dynamic over the past two years with a number of significant erosion events observed across most beaches.

"This has been most pronounced on Wamberal and Ocean Beaches.

"Ocean Beach is exposed to a long southerly fetch and as such is subject to infrequent, but very high energy south swells which originate in the southern ocean and can cause significant erosion as can be observed at Ettalong Point.

"Unlike the open coastal beaches, Ocean Beach is less exposed to more frequent average swell waves from the east and north east which deliver sediment back to the shoreline and as such the recovery of this beach from an erosion event is much slower than on the open coast.

"It should be noted that it can take several years for a beach to return to its pre-storm condition after one major storm or several smaller storms in quick succession.

"Longer erosional phases are linked to climatic cycles such as the Southern Oscillation.

"For example, erosional phases are correlated with La Nina events (as experienced over eastern Australia for the past two years), which are years when there is a higher frequency of storms along the east coast of Australia.

"Alternatively, phases of positive sediment budget, when there is a lower frequency of coastal storms, are linked to the El Nino events.

"Fluctuations in beach morphology, from erosional to accretional forms, also operate over longer time intervals because the frequency of El Nino and La Nina events fluctuates over decadal periods.

"Long term trends in beach morphology are also related to changes in sea level, which can induce phases of erosion (rising sea level) and accretion (falling sea level)," he said.

Mr Melican said the management plans were expected to provide holistic and long-term guidance to the management of the coast line.

In the meantime, the council would continue to work towards establishing and improving dune vegetation along Ocean and Umina Beaches, he said.

He said the erosion at Ettalong Point, Ocean Beach, had been monitored closely since June 2009 with three monitoring points established within the dune system.

An initial measurement was taken from each point to the active erosion scarp and subsequent measurements were taken fortnightly for the first three months and biannually thereafter.

"This monitoring provides an indication of the amount of dune being eroded across the beach," said Mr Melican.

"To date the dune has receded up to seven metres in some locations."

Media Statement, 13 Apr 2012

Larry Melican, Gosford Council