Protect Wooli

Protect Wooli From Coastal Erosion

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Waves and Currents

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One of the most important parts of developing numerical models of the coast is good  wave and current data.

Effective data collection will involve deployment of wave/current meters (also records water levels (i.e. tides)) at 3 sites  with sediment traps (3 heights) attached.

The instruments will be deployed for 8 weeks.

At this stage it is unknown if local wind data is available. These data will be collected using an onsite system (e.g. a windbird) if no data exists.

CCPA plans to conduct this research as early in 2012 as feasible.

Results will be published on this website.

Underwater Topography

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One of the most important parts of developing numerical models of the coast is good underwater topography (or  bathymetry) data.

At this stage it is unknown whether the Wooli area is scheduled for a multibeam  survey (there has been mention of the NSW Government undertaking this for the whole  coast). A bathymetry survey of the area using a single beam system has been costed into this  study in the meantime,

Effective data collection will involve:

1. Deployment of wave/current meters (also records water levels (i.e. tides)) at 3 sites  with sediment traps (3 heights) attached.

2. Bathymetry survey of the embayment out to 15-20 m deep

3. Drop-camera video survey.

4. Grab sampling.

Following the deployment of the wave/current meters, topography and bathymetry survey will  be undertaken. Small sediment samples of the beach and seabed material will also be  collected for grain size analysis for development of a sediment size map and input into  sediment transport modelling.

The instruments will be deployed for 8 weeks.

At this stage it is unknown is local wind data is available. These data will be collected using an onsite system (e.g. a windbird) if no data exists.

CCPA plans to undertake this work as early in 2012 as feasible.

Results will be published on this website.

Photography

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Taking hourly images is a very effective method of beach data collection.

Commercial systems such as the ARGUS system (e.g. as used at the Gold Coast Reef) have been in operation for more than a decade. Cameras are positioned in a stable location as high as possible above the beach (e.g. the water tower at Wooli), and images are collected and either stored or sent to a web-site. Images can then be analysed to develop a quantified understanding of beach response and trends. With today ‘s technology there are many inexpensive options such as an HD video camera in a housing using a smart-phone to transmit images, or a HD webcam sending images straight to the internet (as with many of the surfing forecast sites worldwide). It works well as long as the images are of high enough resolution and the camera location and elevation along with sufficient image control points are known.

For example, ASR runs a very simple automated system at its technical headquarters in Raglan, New Zealand. Hourly images from high above the beach and harbour entrance are posted on  www.snow.co.nz which are automatically downloaded to ASR ‘s server, automatically rectified  and added to an archive tool that allows the user to visually assess the data, fit  curves and trend lines to the harbour delta, match images of any period of time to  the coincident wave and wind data, etc   These rectified images provide a great deal of information on beach processes with respect to the surf-zone, which can be used to infer bars, rip-cells, etc.

CCPA is in discussion with the Council to gain access to the water tower so that cameras can be mounted there. We are also working with CVC to cost the system with a view to applying for public funding if necessary.

Once the system is operational its results will be posted on this website for members information

Historical Evidence

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There is an untapped resource in Wooli with the potential to contribute substantially to our understanding of what has shaped the beach and river over past years and decades:  the collective knowledge, records and observations of the community. Our research contacts at University of Queensland and at ASR Ltd emphasised the value of this type of data.  It is clear from meetings and informal discussions that there are many photographic records and opinions about what happens on the beach and why, supporting evidence and ideas about improving the beach protection strategy.

We are conducting an exercise to  gather the photos, observations and ideas of the Wooli community which will then be collated and made available to potential researches, and other stakeholders.

Tim Heldt will facilitate the process with support from Daryl and Marlene Harper.  Juliet Thommason will make sure we get good quality copies of the material loaned to us. But the vital people are those in the Wooli community who have seen and photographed the changing face of the river and beach.

 

If you can contribute stories or photos or just ideas, contact  Tim Heldt at wild-ash@bigpond.net.au, Daryl Harper at daryl.h@optusnet.com.au or see Bruce at the Post Office. Please identify photos and documents with your name or better still, copy or scan them so that irreplaceable originals don’t get lost.  All originals will be scanned and returned and the results of the study will go up on the Protect Wooli website.


Beach Surveys

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There is little data available with respect to trends for Wooli Beach, which has been  impacted by the training of the river entrance at the southern end and other human  developments. Collection of times series data of beach state/position provides very important information with respect to long-term trends and beach response (erosion or accretion) to  different types of events.

Our initial survey will establish bench marks for each profile along the full length of the beach. Once this is done regular surveys are a relatively easy and cost effective method of recording beach changes using standard land survey equipment (e.g. a total station). While the more data the more often is always best, bimonthly or quarterly surveys would be adequate, with the addition of post-storm surveys if possible. Profiles positioned 200 m apart along the length of the Wooli settlement, with wider spacings (400-500 m) along the other parts of the beach would be more than sufficient.

CCPA is very fortunate to have Brian Saye as one of its Members as he is a professional surveyor and has agreed to lead the team to undertake the surveys. Brian is in regular contact with Council surveyors to ensure the data coming from our surveys is suitable for use in developing the long term protection strategy for Wooli beach.

The results of the surveys will be published here as they become available in early 2012