Kangaloon Aquifer Issues

Tuesday, July 04, 2006

First CRG Meeting

The inaugural meeting of the CRG occurred last night (Monday 3/7/06) and it was an opportunity to meet with the other community representatives and those people representing Wingecarribee Shire Council, NSW Farmers Association and the Hawkesbury-Nepean Catchment Management Authority.

The meeting was spent familiarising ourselves with a lot of the technical detail behind the borefield development proposal, and following introductions, Graeme Head, the CEO of the SCA, gave a brief overview of the Metropolitan Water Plan (2006) and explained how the Kangaloon (Upper Nepean) groundwater proposal was a severe drought contingency measure. The actual trigger point for pumping from the aquifer has yet to be determined, but figures being quoted are when the total water storage reaches between 30-35%.

John Ross (SCA) gave an in-depth look at the pilot studies undertaken at Kangaloon and there are two reports available on the SCA website, the Groundwater Investigations Report and the Technical Overview Report, both published June 2006. I felt that there were many questions raised by the Groundwater Investigations Report, and I will post these questions, and any answers that I find soon.

You can HAVE YOUR SAY about the groundwater extraction proposal and these preliminary studies, up until 18 August 2006.

Many issues were raised during the meeting, and some questions were answered by SCA staff, however there was little time for discussion by members of the CRG. The next meeting is planned in 3 weeks.


One of the main concerns is that many of the local rivers rely on base flows from the aquifer during prolonged drought. Which of these rivers and streams, including the Nepean, Kangaroo, Shoalhaven, and Macquarie Rivulet will be affected is a huge issue. The Groundwater Investigations Report p17 states that the aquifer generally flows from the south to the north, and that while streams near to (~2 km away) will be affected by the drawdown effects of pumping the aquifer for 2 years, that the impact would be negligible further downstream on the rivers flowing to the north (eg Nepean) further downstream.

To recharge the aquifer (fill the hole) the water would be pulled along the gradient mainly from the south, so the question is, will the south flowing sandstone gorge rivers, eg Kangaroo, be eventually impacted by the extraction of groundwater, and is there any risk to the Wingecarribee Swamp, only a few km away from the borefield?
(There are monitoring bores in Wingecarribee Swamp and I was told at the meeting that the data from these bores would be integrated into the study, but how and when were not provided).

Community members are very concerned about the impact of the proposed borefield on surface springs and wetlands, as they understand that there must be some interconnectedness between the deep aquifer and surface aquifers (as the pressure of water from above pushes water through the sandstone layers). The report claims that there is no connectivity between the groundwater found in the basalt, a surface aquifer, and the deep sandstone aquifer that has been monitored and tested along Tourist Rd. The water chemistry, including salinity levels, shows the water from the two sources to be different. In addition, the assumption is that the Wianamatta Shale, which underlies the Tertiary Basalt, is impermeable to groundwater so the water moves laterally along the top of the shale layer rather than permeating through it, so where the basalt meets the shale, springs are found. However, even if this is the case, it is likely that there will be a drawdown effect on surface aquifers, which are sandstone, due to their interconnectedness, and this may include sandstone swamps such as Stockyard Swamp.

Q. Will there be an impact on surface springs, soaks and wetlands in the basalt formation due to a lowering of the zone of saturation in the sandstone, and the fact that less water will travel further because it will be pulled into the dryer sandstone rather than running off into a creek? Can the SCA/DNR show evidence to the contrary?


  • Hi Karen.

    Thanks for posting such a comprehensive report of the meeting. I hope that you can analyse some of the papers for your readers.

    My main query is to ask what input the Dept of Environment and Conservation is having in this whole aquifer exploitation process. We know there are endangered species and "endangered ecological communities" and even a RAMSAR site (Butler's Swamp) directly within the immediate area of exploration, and proposed exploitation of the aquifer.

    Part of the DEC website says:

    "The Threatened Species Legislation Amendment Act 2004, passed by Parliament in November 2004, signals the NSW Government’s commitment to further integrating conservation with mainstream decision-making about how we use land and build our economy.

    The new reforms are aimed at establishing better frameworks and processes so that landholders, developers, farmers, community groups and government agencies can more effectively contribute to protecting the State’s biodiversity."

    What is D.E.C. doing to fulfil its obligations under its own Act?

    After all, is SCA not part of the same Ministry?

    Denis Wilson

    By Blogger Denis Wilson, at 6:42 AM  

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