Kangaloon Aquifer Issues

Thursday, August 17, 2006

Key Points from Dr O’Loughlin’s Talk at a meeting of the National Parks Association, Moss Vale on Tuesday 1st August 2006

Dr Emmett O’Loughlin, a retired catchment hydrologist, initially explained where the water in the aquifer comes from, and described recharge as “throttled” rainfall. The aquifer dips down 1.3% to the North-East and the water travels through the coarse rock mass and the crumbled fault zones. The highest recharge zone occurs close to Tourist Road, at the proposed borefield site, and is estimated that 5% of the rainfall that falls onto the exposed sandstone reaches the aquifer.

The hydrogeological model that processes input data and forms the basis for many decisions was summarily discussed. According to the expert review, the main error sources in the model were listed as:
Properties of the aquifer
Boundary conditions
Connections between aquifers
Recharge rates

While recharge rates are essentially “unknowable”, estimates can be improved by improving inputs into the model. Significant improvements to the model can be made with further data and Dr O’Loughlin stated that we need 5 years to understand the configuration of the aquifer and to gather sufficient field data and real time data. The current model has been based on 18 months of data. The main improvements to be made include:
Installation of gauging stations in permanent streams.
Transient calibration runs, preferably with a meteorological station on site for actual rainfall records.
Boundary conditions must be improved by obtaining known ground levels along permanent streams and the escarpment. Unless these are known the model will lack credibility. These data could be obtained by a small survey team of 2-3 people over 3 weeks. This was considered a major data gap and weakness in the model.

Negative uncertainties that need to be considered, in relation to recharge, include climate change and afforestation. Despite the pessimistic rainfall decile 10 being used, Dr O’Louhglin felt that the negative consequences of climate change should suggest that a lower estimate be run in the model. Positive uncertainties include bushfire (increases recharge), and technical uncertainties included recharge rates and aquifer properties.

According to Dr O’Loughlin, one of the main advantages of aquifer water supply is the savings in losses from evaporation, which occurs from the surface area of large dams. Approximately 1 GL/yr is lost from the surface of 1 km2 over 1 year. For an example, Wingecarribee Reservoir would lose approximately 7 GL/yr. However this advantage is not available in the Kangaloon aquifer scheme as the water will be lost during transit to and in storage prior to distribution.
Another advantage is flexibility, given that the cost per bore is around $100 000, and the overall cost of this scheme is around $40-50 million. Nothing about the scheme is irreversible, and bores can be excluded or included as required. The community reflected the concern that once the infrastructure was in place it was very unlikely that the SCA would “turn off” any bores.

Question Time
This was the first opportunity for public consultation with members of the CRG. State MP Peta Seaton, and two Wingecarribee Shire Councillors were present. Following the presentation questions were invited from Dr O’Loughlin and CRG members, Ray Nolan, Leon Hall, Mim Merrick and Karen Guymer.

One audience member requested that the SCA sample water from the springs and compare it with the aquifer water to test the assumption that these water sources are separate. A five-year moratorium was requested so that more comprehensive testing and improvements to the model could be made. Community members were very concerned about the possibility of greater amounts than 15 GL/yr being extracted.


  • Dr O'Loughlin's talk was excellent. You have given a good report here.


    By Blogger Denis Wilson, at 4:58 AM  

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