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Wednesday, September 19, 2007

The Cataract River is dying. The George's River is dead.

Day 2 of the Southern Coalfields Inquiry was held today. They started with formal hearings in the morning, and then moved on to a Field Trip to the Cataract and Georges rivers.

Well, having gone down to the Cataract Gorge today, I can say that the Cataract River is in a very poor state, but it appears not to be dead. Not quite, anyway. But it is in a serious state. Certainly one would not want one's kids swimming in it.

The condition of the River is a result of cracking of the rock base of the rivers, as a result of subsidence, as a result of coal mining, by Longwall Mining techniques.
For readers less than familiar with the fine print on maps of NSW, we are talking about two of the rivers in the southern catchment for Sydney's drinking water. The Nepean River is the longest of these rivers, and it rises near Robertson (as you will know).
It flows down through the sandstone plateau north of Kangaloon, and, in the habit of Australian rivers, it meanders around, on its way towards Sydney. Then it goes past Camden (south from Sydney), and suddenly it goes in a huge loop, skirting around the base of the Blue Mountains, (passing west of Sydney) through Penrith, Richmond, Windsor. It becomes the Hawkesbury River, where upon it flows north to Wiseman's ferry, and then flows east, towards Gosford, and Woy Woy, and enters the Pacific Ocean, at Broken Bay - half way between Sydney and Newcastle. There are a number of smaller rivers, the Cataract, the Cordeaux and the Avon which all are tributaries of the Nepean River, which rise on the Illawarra (Woronora) Plateau. It is these Rivers which we have mostly been dealing with in the hearings of the Southern Coalfields Inquiry, this week. Then there is the Georges river, which rises close to the Cataract river, but takes a "short cut" to the ocean, by flowing past Campbelltown, then Liverpool, and suddenly it arcs eastwards, and flows into Botany Bay on the southern side of Sydney.
Cataract River - Douglas Park, 19 September 2007.
The water I saw with my own eyes, today, in the Cataract River today, is a greenish-grey colour, in most places, and there is sludge on may of the shallower pools. The water is quite opaque. It must be remembered that this river was in flood 2 months ago, so much of the algal blooms and bacterial "floc" (mats of floating iron oxide stained material) has been washed downstream by those floods. We were walking over dried, dead algae on the rocks. The river clearly has been much, much higher in the past. In fact that is the main thing I noticed - the "high tide" marks on the rocks, (clearly visible on the taller rocks beyond the pool, in the photo above) indicating the levels at which the water used be - back in the days before mining cracked the Cataract River, and allowed most of the water to escape down into the bedrock below (somewhere).
Methane Gas bubbles emerging
(in this case, occasional large bubbles making an audible "Glubb" sound).

And, of course, water being water, there is always a two-way flow with gas bubbles emerging from the coal seams some 350 metres below the surface of the rock. And, also iron and other minerals (exposed by water dissolving minerals from below, as a result of the cracking), as a result of the mining having caused subsidence. This all contaminates the streams.
A fine stream of tiny bubbles rises to the surface,
then the bubbles float downstream.
Here is Caroline Graham, one of the long-term campaigners for the health of the rivers, and a foundation member of Rivers SOS - a voluntary body of some 30 member organisations across NSW, including the Hunter Valley region, which is currently facing so much stress from mining. Caroline was responding to an Illawarra Coal representative, who had been making a presentation of what he claimed was a highly successful "remediation" effort at "Marhynes Hole" on the George's river, near Appin. Amongst the claims made by this representative of the coal mining company responsible for the damage in these two rivers, was that in this case they had been able to preempt damage to the river, by installing a "grouting curtain" - a series of deep drill-holes, which were then filed with a cement and bentonite grouting. This process is intended to release pressure in the bedrock. Judging by the evidence of fallen rock in an area in the river where a rock ledge forms a kind of natural barrier, their attempts were not very successful (despite the claims made for the merits of this system).

The paper Caroline is holding says "Missing River", referring to a time when this part of the George's River had dried up entirely. It was flowing today, but not very much, as we could easily step across the river in a few steps from rock to rock. Its flow is not that of a "river" - it is reduced to just a small stream.

One part of the presentation from the man from Illawarra Coal annoyed me intensely. He showed us a particular graph which purported to show that prior to "remediation", the flow of water in this section of the George's River was much lower than it is now (after remediation). I asked what the input flow rates were in the River, for the various data in the graphs. His answer was that the two sets of data were both collected at times of "low flow".

What the bloody hell does that mean?

For a graph purporting to measure river flow loss, this graph is a nonsense, and is not worth the paper it is printed on - and I said so, publicly.

I was quickly shut down by one of the members of the Panel (Drew), who said it was not appropriate for me to cross-examine the man from the mining company like that. I subsequently (privately) pointed out to Drew that as Garry was making claims, in public, which were not supported by facts, I would have been irresponsible of me to not to have challenged his claims.

I spoke privately with Garry after that interrupted exchange. I commented that, as a former bureaucrat I was not impressed with "pretty graphs" which meant nothing, because there was no factual data to back the graphic presentation. His response was: "Some people like pretty graphs".

I found his presentation intellectually dishonest, and demeaning, from the point of view of the company which he apparently represents.

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