The Kangaloon Aquifer - The SCA's pamphlet

Here is a link to a pamphlet about the Kangaloon Aquifer, which the SCA was handing out at the Robertson Show on Saturday. This document is extremely vague in its assertions on two critical issues: The age of the groundwater, and whether it is linked to the groundwater that feeds the springs in Robertson and the Kangaloon Range, and other basalt hills in the Southern Highlands.

Is this a separate resource to others in the
Southern Highlands?
The high volumes of available groundwater and very low salinity suggest that the groundwater resource in the Upper Nepean sandstones is separate to the other areas to the south, south west and west of Kangaloon.

Hmmm, “Interesting”. The salinity issue is related to the presence of the Wianamatta Shale in the region, for (apparently) if there is leakage of groundwater through the shale layer, it can increase salinity in the Aquifer. (So I have read elsewhere in the SCA website.) But I am puzzled by the reference to high volumes indicating that the Kangaloon Aquifer is not related to the basalt-based springs in the Robertson and Kangaloon hills. After all, we are in the highest rainfall area in the State.

Will my springs and bores be affected?
Most groundwater users in the area access springs for their water. Springs occur in the higher basalt areas of the catchment and are not connected to groundwater in the sandstone. They will therefore not be affected by SCA
production bores and borefield pumping.

Hang on! In half a page, they have moved from claiming that indications “suggest that the groundwater resource … is separate …” to “Springs occur in the higher basalt areas of the catchment and are not connected to groundwater in the sandstone.”

A categorical statement, to support their proposal, without a scrap of evidence! Worse, it is contradicted by earlier Government studies.

It is my understanding that the basalt rocks which form the hills of Robertson and Kangaloon and many of the typical green hills of the Southern Highlands, were extruded up (in a volcanic process) through the older Sandstone layers (which one sees on the escarpment), and through the Wianamatta Shale layer. The basalt is heavily fractured rock, and so it is permeable, allowing water which falls as rain in the local area to seep down through the basalt, through the shale and into the sandstone layers.

I am not a geologist, but in April 1998, the (then) Dept of Land and Water Conservation produced a paper: “Aquifer Risk Assessment Report”. On P6, there is a table “Sydney South Coast Region”. Within that table there is a category “Medium Risk Aquifers”. It lists:

Southern Highlands Fractured Rock (aquifer) (approx. Wingecarribee Shire LGA boundary).

I am more persuaded by the DLWC scientific assessment of all of the aquifers in NSW than the self-serving propaganda put out by the SCA, to justify a political decision by the Government of the day to drain the Kangaloon Aquifer, and in so doing, let itself off the hook with the proposed Desalination Plant at Kurnell.

More about the age of the groundwater later.