Beach erosion: an alternative view

As a counterbalance to an article in our last edition, the Kiama Greens have been in touch to present an alternative view:

Jones Beach Response

Aftermath of the 1974 storm surge at Jones Beach

Aftermath of the 1974 storm surge at Jones Beach

Kiama Greens, along with support from the local residents and the local community are concerned by BeachCare Kiama’s claims regarding modification of Jones Beach dune structure and vegetation and the impacts of sand dune vegetation on beach safety. Beaches are dynamic and ever changing, and a beaches current condition depends entirely upon current storms. While it is unfortunate that storm damage can leave a beach less usable for surfers and swimmers until it repairs itself over time, that is not a reason to remove vegetation and dunes to create a perfect flat sandy surf beach.

Warren Holder Spokesperson for Kiama Greens said “The pressures to modify dune vegetation at these beaches by the Beach Care group and supported by Councillor Mark Way is highly contentious”.

At the heart of the conflict over the future of this dune vegetation are a number of “vested interests,” including: views of the ocean impacted by the dune vegetation and the quality of waves required for a quality surfing experience.

It’s important to understand the role this vegetation plays in protecting resident’s homes and providing ecosystem services.  Shrubs and trees build the dunes by collecting windblown sand, and the plant roots then stabilise this sand.  Reforming the dune by removing vegetation at the front of the scarped dune at Jones Beach to reinstate low growing spinifex, as suggest by Beach Care, could change the dune structure and contribute to dune retreat.

These grasses are ephemeral and normally occupy the frontal incipient dune area that has been temporarily washed away. It would be wiser to replant these grasses when this area re-establishes itself naturally. Unfortunately, there is little opportunity to mimic a natural beach vegetation sequence because the zone between the beach and residents at Jones Beach is limited.

The storm surges last year actually demonstrate how well the current dune vegetation has done its job, the beach area washed away but the vegetated dune held firm.

Before actions to modify this vegetation are considered by Council or local land care groups we need to be patient and understand the cyclic nature of beach sand movement and replenishment and wait to see if the sand returns as it usually does. We don’t really know what role sea level rise will play in this process over time so we need to be very cautious in our response.

An informative ABC Bush Telegraph in 2014 (attached) related the potential loss of residential properties to beach erosion at Old Barr (Taree Council)[1] and raised the very real spectre of a possible 100 metre beach retreat for every 1 metre of sea level rise (the Bruun rule). So understanding beach hydraulics in the context of rising sea levels should inform planning before we allow headstrong residents and Councillors to intervene in such dynamic beach systems.

The CSIRO informs us that sea levels have already risen by over 200 mm and are currently rising at around 2.5 mm a year. They also tell us that this increase amplifies the effects of high tides and storm surges[2].  So clearly the sea is rising and threatening our coastline and this community dispute may well be the first of many climate change related conflicts that we need to resolve in an informed and rational way.

Kiama Council initiated the dune revegetation program at Werri and Jones Beaches more than 25 years ago to stabilise the dunes and protect properties against ocean surges. It has worked effectively and is even more relevant today as we experience climate change impacts.

Regrettably Council has no plan to respond to sea level rise and the current state government has let them off the hook by relaxing sea level planning requirements.  We urge Council to address its obligation to undertake a coastal zone risk management plan that considers impacts of sea level rise before making decisions that could increase coastal risks for residents. Otherwise these conflicts will be driven by uninformed opinions and ad hoc solutions while storms increase in intensity and frequency and the ocean continues to rise and threaten beach ecosystems and residential properties.

When asked about claims by the Beach Care Group of the increased chances of rips on beaches due to sand dunes Warren Holder said: “I personally can’t see any connection at all between any increase in rips due to the dunes on any beach. If for one of many reasons waves wash up against a vertical wall of sand the waves will be reflected as backwash. Backwash is not a rip and it does not behave like a rip.”

More information at: www.saveourdunes.kiamagreens.org.au

[1] Professor McDonald – ABC Bush Telegraph program April 2014  http://www.abc.net.au/radionational/programs/bushtelegraph/coastal-planning/5364818

[2] CSIRO/ Bureau of Meteorology State of the Climate Report 2016

 

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