Wednesday, December 24, 2008
I had known for a long time that one of these little gullies (which head off towards Sydney, from the northern edge of the Robertson district) was the actual head of the Nepean, but apparently this is it.
The light was suitable, in the late afternoon for photographing the local valley, which I had ascertained from some other friends, was indeed the head of the Nepean River. Emma confirmed it for me.
Looking westward, and uphill, you can see the boundary of this catchment. Just over this hilltop, in the westerly direction, one comes to Robertson proper, and the headwaters of Caalang Creek, the start of the Wingecarribee River system- which runs to the Wollondilly River and hence to Warragamba Dam. So, over the hill lies a different catchment.
Click on these images to enlarge them (to make reading the labels easier).You can see where there is a very small farm dam, which I have marked (above) and the line of a soak which leads down to the first properly formed creek line - the true start of the Nepean River valley.This lovely scene shows the real start of the Nepean River - as a recognisable creek.And to put it all into the picture, this image shows the start of the Kangaloon forested area which is the start of the Sydney Catchment "Special Area". In the far distance is the Kangaloon Aquifer area, and the main part of the "Catchment".
Once the Nepean River crosses "Tourist Road" (about 3 kilometres below this point) it enters the true "Catchment" it becomes a classic river on a sandstone rock base (having started up here in the basalt "red soil" country). Once within the sandstone area, it quickly starts to form a series of canyons and gorges.
The Nepean River merges with the Hawkesbury River, at the base of the Blue Mountains. The Hawkesbury-Nepean River system defines the "Sydney Basin". This giant river then enters the ocean at Broken Bay, north of Lion Island, just north of Palm Beach (north from Sydney).
The Hawkesbury is the major river which one crosses on the way north to Newcastle. Gosford is located on the northen side of the River, as it enters "Broken Bay".
Very few people, (especially few Sydneysiders) realise that the mighty Hakesbury-Nepean River system starts right here, on the edge of Robertson. Silly them!
Thursday, October 09, 2008
Longwall Mining under rivers and aquifers is totally unsustainable, and against the best interests of society as we know it.
Humans have not evolved to drink coal – we need water.
What is Longwall Mining?
Longwall Mining is an underground mining technique using a huge rotary cutter (“shearer”), on a rail system, which extracts coal from a seam in continuous “faces” up to 300 metres wide. Each “panel” of removed coal may be as long as 2 kilometres. The height of the “shearer” is adjusted to the coal seam being extracted, but in the Illawarra region it averages approximately 2-3 metres high.
Longwall Mining machine, with "shearer" and rails.
In effect it cuts out an underground “room” as wide as 3 football fields are long, and extending for 2 kilometres in length. That is for each single panel. Panels are normally laid out in series, separated by walls of coal, known as “chain pillars”, which vary in thickness from 20 to 50 metres wide.
As mining progresses, the roof of the excavated area is allowed to collapse into the void (known as a “goaf”) behind where the shearer has been working. A collapse zone is formed above the extracted area. Above the collapse zone is a fractured zone where the permeability is increased to a lesser extent than in the collapse zone. Above this level, the surface strata will crack as a result of bending strains, with the cracks varying in size according to the level of strain, thickness of the overlying rock stratum and frequency of natural joints or planes of weakness the strata (Holla and Barclay 2000). The principal surface impact of underground coal mining is subsidence (lowering of the surface above areas that are mined).
Diagram of Longwall Mining - BHP.
(Click to enlarge - there is a tiny figure of a miner there - for scale).
The following notes have been extracted from the NSW Scientific Committee’s declaration of Longwall Mining as a Key Threatening Process under Schedule 3 of the NSW Threatened Species Conservation Act 1995.
1. Longwall mining occurs in the Northern, Southern and Western Coalfields of NSW. The Northern Coalfields are centred on the Newcastle-Hunter region. The Southern Coalfield lies principally beneath the Woronora, Nepean and Georges River catchments approximately 80-120 km SSW of Sydney. Coalmines in the Western Coalfield occur along the western margin of the Sydney Basin. Virtually all coal mining in the Southern and Western Coalfields is underground mining.
2. Longwall mining involves removing a panel of coal by working a face of up to 300 m in width and up to two km long. Longwall panels are laid side by side with coal pillars, referred to as "chain pillars" separating the adjacent panels. Chain pillars generally vary in width from 20-50 m wide (Holla and Barclay 2000). The roof of the working face is temporarily held up by supports that are repositioned as the mine face advances (Karaman et al. 2001). The roof immediately above the coal seam then collapses into the void (also known as the goaf) and a collapse zone is formed above the extracted area. This zone is highly fractured and permeable and normally extends above the seam to a height of five times the extracted seam thickness (typical extracted seam thickness is approximately 2-3.5 m) (ACARP 2002). Above the collapse zone is a fractured zone where the permeability is increased to a lesser extent than in the collapse zone. The fractured zone extends to a height above the seam of approximately 20 times the seam thickness, though in weaker strata this can be as high as 30 times the seam thickness (ACARP 2002). Above this level, the surface strata will crack as a result of bending strains, with the cracks varying in size according to the level of strain, thickness of the overlying rock stratum and frequency of natural joints or planes of weakness in the strata (Holla and Barclay 2000).
3. The principal surface impact of underground coal mining is subsidence (lowering of the surface above areas that are mined)
Damage to some creek systems in the Hunter Valley has been associated with subsidence due to longwall mining. Affected creeks include Eui Creek, Wambo Creek, Bowmans Creek, Fishery Creek and Black Creek. Damage has occurred as a result of loss of stability, with consequent release of sediment into the downstream environment, loss of stream flow, death of fringing vegetation, and release of iron rich and occasionally highly acidic leachate. In the Southern Coalfields substantial surface cracking has occurred in watercourses within the Upper Nepean, Avon, Cordeaux, Cataract, Bargo, Georges and Woronora catchments, including Flying Fox Creek, Wongawilli Creek, Native Dog Creek and Waratah Rivulet. The usual sequence of events has been subsidence-induced cracking within the streambed, followed by significant dewatering of permanent pools and in some cases complete absence of surface flow.
Subsidence associated with longwall mining has contributed to adverse effects (see below) on upland swamps. These effects have been examined in most detail on the Woronora Plateau (e.g. Young 1982, Gibbins 2003, Sydney Catchment Authority, in lit.), although functionally similar swamps exist in the Blue Mountains and on Newnes Plateau and are likely to be affected by the same processes. These swamps occur in the headwaters of the Woronora River and O'Hares Creek, both major tributaries of the Georges River, as well as major tributaries of the Nepean River, including the Cataract and Cordeaux Rivers. The swamps are exceptionally species rich with up to 70 plant species in 15 m2 (Keith and Myerscough 1993) and are habitats of particular conservation significance for their biota.
Flora and fauna may also be affected by activities associated with longwall mining in addition to the direct impacts of subsidence. These activities include clearing of native vegetation and removal of bush rock for surface facilities such as roads and coal wash emplacement and discharge of mine water into swamps and streams. Weed invasion, erosion and siltation may occur following vegetation clearing or enrichment by mine water.
Source: “Alteration of habitat following subsidence due to longwall mining as a KEY THREATENING PROCESS” NSW Scientific Committee
The Dept of Environment and Climate Change (formerly DEC) has done the right thing (in making this declaration), but it is an appalling indictment of the decision makers in the NSW Government, and particularly the Mining Department and the Department of Planning, that they have allowed, indeed promoted, the use of these disastrous mining techniques under the Rivers which are the catchment for Sydney's water supply.
When the estimated 91% of the Illawarra Catchment has been undermined (estimated at some 20 years), what will Sydney do for water, then?
This map shows coal leases under the Illawarra Catchment 5 dams and rivers (Source: NSW Dept of Planning)
The DECC as a "Toothless Tiger".
Don't get me wrong, I support what they have written. But have they really exercised their full powers under the Threatened Species Act to actually prevent damage being incurred? Or have they just issued a "determination" - and left it at that?
These are just some of the powers available to be exercised by DECC:
Interim Protection Order: Minister for the Environment may make an interim protection order for a period of up to two years over an area of land that has natural, scientific or cultural significance. The Minister may also make an interim protection order on land where the DEC Director-General intends to exercise functions relating to threatened species, critical habitat, or declared critical habitat under the NP&W or TSC Acts.
Stop Work Order: The Director-General of DEC may make a stop work order for a period of 40 days if an action is being, or is about to be carried out that would harm a threatened species, population or ecological community or it’s habitat. These orders can be renewed for 40-day periods as required.
I haven't heard of any such powers being used to stop Longwall Mining by BHP Billiton (or their subsidiaries) or their international mining conglomerate allies, such as Metropolitan (Peabody Pacific Pty Ltd) or Gujarat NRE.
Monday, April 28, 2008
THAT WAS DONE AT THE INSTIGATION OF THE LEGAL COUNSEL FOR PARSONS BRINCKERHOFF.
THEIR REASONS ARE STATED BELOW.THIS BLOG RESERVES THE RIGHT TO EXPLORE ISSUES OF PUBLIC ACCOUNTABILITY.
Monday, March 31, 2008
OK - Good thing to close an unsafe bridge, you might say.
The interesting thing is that this local road, in the Douglas Park area, is in a direct line with the seriously compromised Twin Bridges, on the F5 Freeway (Hume Highway). I say "seriously compromised" but the RTA officials would dispute that. They are entitled to their point of view. I should just settle for saying these Bridges have been "seriously reinforced - at the expense of BHP Billiton".So why did BHP Billiton pay for that bridge repair? Because clearly the RTA was concerned to protect the Twin Bridges from possible damage, because of subsidence, caused by coal mining by BHP Billiton just to the north of the Twin Bridges.
And that takes us back to the Morton Park Drive bridge. It is just north of the Twin Bridges - in a direct line. The Wollondilly Council has closed the bridge on Morton Park Road, because it says it cannot afford to pay to repair it. Why does it not send the bill to BHP Billiton, as the RTA has done?
And this is not the only case of a bridge in that area which has been closed. There is an historic bridge, called the Maldon Suspension Bridge, which is now closed. It is partially dismantled. The official story of this bridge is as follows:"Spanning the picturesque Nepean Gorge, the Maldon Suspension Bridge is one of only a few true suspension bridges in New South Wales. It was built in 1903 to replace Harvey’s Crossing, a stone causeway situated a couple of hundred metres upstream.
The Maldon bridge differs from the normal suspension bridge in that the main cables leading from the towers are carried upwards to an anchorage in the sandstone cliffs above the bridge instead of downwards to ground level. It also has unique curved timber approaches. A bushfire in January 1939 severely damaged the bridge and the original timber towers were replaced with identical steel ones. Maldon Suspension Bridge was closed to vehicle traffic with the opening of the F5 Freeway and the new Picton Road from Wilton in 1980." Macarthur Tourism website.
Saturday, February 02, 2008
After the video, we then went down to the Nepean, north-east of the Twin Bridges at Douglas Park, to where the gas was known to be leaking from the cracked base of the river.
The morning started badly though when I heard a "grab" on the ABC news of Premier Morris Iemma talking about the gas leaks in the Nepean River, we will investigate this, and "if it is real, we will fix it". What an insult: If it is real - indeed.
Pray tell, Mr Premier how you propose to "fix" a gas leak coming through 300 metres of crack rockbase? The man has no idea, and is just mouthing 5 seconds of platitudes, to try and satisfy a journalist's inquiry.
John Kaye MLC (a Greens member of the Upper House) spoke with the Rivers SOS group, and was well received.
Pru Goward, MLA, Member for Goulburn, joined the members of the Rivers SOS group, and Maurice, Julie and myself took Pru down to inspect the area of the Nepean River where the gas is obviously leaking out. Pru made the point that we can only tell that the gas is leaking out through the river bed, because we can see the bubbles. It is quite possible that it is coming out all though this area, along the river bank, though the sand, but we cannot tell. Quite a scary thought, that. Dave Burgess, an environmental campaigner with the Total Environment Centre, was the hero of the day, as the Illawarra mercury carried a page 1 story based largely upon Dave's work to document the cracking of the Catchment around the Dendrobium mine - another BHP Billiton mine.
I took this photo of Dave holding the Page 4 photo of himself lying down, looking into a metre-wide crack in the soil caused by subsidence above the Dendrobium mine. You may read the story here.
Tuesday, January 29, 2008
Caroline Graham of the Rivers SOS group has sent out photos which she took two days ago, of methane gas bubbling out of the Nepean River. This is occurring just near the "Twin Bridges" on the way to Sydney. The gas is coming from the coal seams hundreds of metres underneath the sandstone rock layers.
The gas is naturally occurring (released by the coal seams, but it normally stays trapped by hundreds of metres of sandstone rock), but:
ITS RELEASE IS DEFINITELY NOT NORMAL.
- BHP Billiton, in a press release of 18.1.08, have admitted that the first of their four underground longwall coal mines at this site has caused “minor releases of gas at the surface of the
”. Nepean River
- Methane gas vents on this scale show that the river bed has been extensively cracked and fractured as a result of the current mining operation carried out by BHP Billiton, which is extracting coal here at an offset distance of a mere 180m from the river.
- BHP Billiton indicated in their Environmental Impact Statement that, in their opinion, an offset distance of 500m would be safe for the
, but that this was “not economically feasible.” (This from a company that made $14 billion in profits last financial year). Nepean
So, in effect, BHP has decided that the River can be cracked, and poisoned, because making profits from coal is more important than the health of the Nepean River. It is as simple as that.
The Iemma Government is complicit in this, as it approves the Mine Subsidence Plans which BHP submits in advance of any mining. And, let us not forget that "fees" the companies pay via the Part 3A process under the Environment Planning and Assessment (EP&A) Act 1979, and the "royalties" the Government receives.
Tell everybody you can who cares about this iconic river. After all the Hawkesbury/Nepean basin defines the Sydney Basin (region), and it is the fresh food "basket" for Sydney, and these rivers supply all the water for the entire population of Sydney and Wollongong.
Ring your local Member of Parliament, or ring Illawarra Coal directly.
- Pru Goward MP, the Member for Goulburn in the NSW Parliament, is our local Member in the Southern Highlands. She should know about this already, as I have emailed her directly. Her electorate includes the Nepean Dam (the main reservoir on this river, although the damage is occurring just below that point, and therefore is just outside her electorate.
- Phillip Costa MP is the Member for Wollondilly - and is the State local Member for the area where the damage is occurring.
- Col Bloomfield, President of Illawarra Coal might be prepared to talk to you - you never know your luck!
Iron Oxide staining, algae and bacterial mats
George's River, Marhnyes Hole. 2005
Tuesday, November 20, 2007
This story is a follow up to my blog article of 17 July 2007, where I reported on the problems being created for the Twin Bridges, (and potentially for the huge amount of road traffic which uses this main arterial highway) because of Longwall Mining close to these bridges, by BHP Billiton ("Illawarra Coal").
and single lane traffic, on 17 July 2007.
These restrictions were in place for several months.
I have just had an interview with Nick Rheinberger on ABC Illawarra (following Professor Pells), where I put it to them that Prof Pells is being a bit disingenuous with the audience of ABC Illawarra. Professor Pells stressed that there was a problem in 2005, but some distance away, not under the bridge. If that is the case, why was his company taking core samples directly under the bridge, in July 2007? He could put this issue to rest by publishing the drilling logs taken by his company on 17 July 2007 and the results of a second drilling test done after 17 July 2007, if he maintains that there is no problem under the bridge (as he said on radio this morning). I know what I saw (the cracked core samples).
According to a journalist friend, Professor Pells had acknowledged that there was a problem with the original core samples (possibly they were damaged in handling?).
(DJW comment: Yeah, ... Right!).
Apparently PSM re-did the core samples, and the new ones were fine.
Maybe. But I know what I saw.
It would be simple for Professor Pells to publish the dates and depths and condition reports of the second lot of drilling logs. Without those logs being published then this Blog author stands by the evidence of his own eyes.
I stand ready to correct the record when Professor Pells provides documentary evidence of further core samples at the depths of 18 to 22 metres deep, taken on a later date, having come out solid and not cracked.
Friday, November 09, 2007
Rivers have died. I have seen this with my own eyes.
Tonight Julie and Caroline showed us pictures from the Nepean, Cataract, Georges Rivers and the Waratah Rivulet (part of the Woronora River catchment). They also showed us the short film "Rivers of Shame".This whole issue has recently been debated in front of an "Inquiry into the Southern Coalfields"
Lets hope something useful comes about, as a result of their deliberations.
It is an appalling indictment of the NSW Government, and particularly the Mining Department and the Department of Planning, which have approved these disastrous mining techniques to be used, under the Rivers which are the catchment for Sydney's water supply.
When the estimated 91% of the Catchment has been undermined (estimated at some 20 years), what will Sydney do for water, then?It is crazy to trade off short term profits (from coal) for perpetual loss of water. In every sense it is uneconomical, and environmentally irresponsible.
It has taken some 400 million years to develop the Woronora (Illawarra) Plateau which we know as the Sydney Water Catchment. We are trading this off, for 20 years of profit. How stupid is that?
Monday, November 05, 2007
Yesterday, while I was at Tourist Road, looking for Greenhood Orchids, or other Orchids which appear to favour wet areas, I realised I was being watched by a Japanese Snipe, sitting about 40 metres from the road, right on the edge of a swamp in private farming land, beside Tourist Road. This bird was nearly hidden in long pasture grass, beside the small creek which flows under Tourist Road, across another patch of farming land, and then joins the Nepean River, in the SCA Catchment. We are less than 500 metres from the Nepean River crossing, where I saw this species, last year.This bird was quite nervous, and flew away, once it realise I was trying to photograph it. For all it knew, I might have been wanting to shoot it. Little does it know, I have been working to protect it.
There was at least one other Japanese Snipe about 150 metres away from me, on the near edge of the swamp (in a further distant section). The bird was clearly visible, but the photos are overly pixellated to be good quality, but they are recognisable. They show the bird actively feeding on the edge of the swamp.
Snipes are short-legged Wading birds, with very long bills, which they use to probe soft mud to collect aquatic creatures, worms and crustaceans. They have been long regarded as a "sporting bird" (from the point of view of hunters). They fly very quickly, rising suddenly from cover, flying for a relatively short distance, then dropping suddenly back into deep cover of long grass or rushes and reeds. Once they have landed, they then settle down, and cautiously resume browsing for feed.
As can be seen in these photographs, (even the distant photos) these birds have very large eyes. Furthermore, their eyes are placed on the side of their head - giving them approximately 320 degree vision, perfect for birds which are subject to predation by other birds, animals, and modern homo sapiens hunters. This bird is now protected in Australia and Japan, but as a migrant it has to survive travelling via Indonesia and the Philippines before it returns to Japan and China and Korea, to breed.
Its a dangerous world out there, for Snipes. The long migratory journey itself is a huge challenge, especially in swamps and rivers which are under pressure from industrial pollution. That fact alone reduces their reliable food supplies.
Wednesday, September 19, 2007
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.
(in this case, occasional large bubbles making an audible "Glubb" sound).
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.
Tuesday, July 17, 2007
If so, then the likely cause is longwall mining in the nearby coal mines.
Douglas Park Bridge - northbound
Douglas Park Bridge - southbound
Drilling Rig - in situ,
under the Twin Bridges
Official Job Number and description
Core Sample - trays - various marked depths
As you can see, the RTA has hired a drilling company to test the rock base under these Twin Bridges, at Douglas Park. Why?
Well, there has already been longwall mining conducted in the area. There is further longwall mining likely to commence in several months time. So, it would appear that they are checking to see if fracturing of the bedrock foundations of the Bridge has already occurred. Has it? I understand that it is very likely that it has occurred - but I am not an engineer.
Alternatively, they are assessing the risk of future fracturing of the bedrock foundations, once the new longwall mining commences.
Meanwhile, from what you can see, in today's traffic flow restrictions, it is reasonable to assume that the RTA is sufficiently worried about its Douglas Park Bridges to limit the traffic loading on the Twin Bridges.
Let us hope that they can exert enough influence on the mining companies to prevent longwall mining in the area. For subsidence, should it occur, could render this bridge unsafe. The social, physical and economic costs of these Bridges, should they need to be to be closed for repairs could be extraordinary. These bridges are an enormously critical part of the Australian road infrastructure.
Do you think I am kidding? You do the sums on how much freight goes over these Twin Bridges, each day, going to and from Sydney from Melbourne and Canberra, and other parts of the country.
Further damage to the Twin Bridges is surely preventable. It just requires the NSW Minister for Transport to step in to prevent further mining in the area. He just needs the balls to stand up to Frank Sartor, Minister for Planning, who is the guy who authorises these longwall mining activities. No worries.
These Twin Bridges span the Nepean River, at Douglas Park. The Nepean River rises at Kangaloon, just south of Robertson
Friday, June 29, 2007
the amount of iron
contamination left by
4 months of pumping.
The SCA has temporarily stopped pumping from the Kangaloon Aquifer. They did this last last Wednesday 20 June 2007. We have not commented on this up until now, as we did not know quite what the SCA was "up to". Here is a photo taken by a "research assistant", showing pump outlet no longer running. The rust staining is clearly evident. It is iron contamination from the water in the Aquifer.
What a crock ...???
First day of pumping.
The reality is that the Nepean Dam is full, (confirmed by SCA's Bulk Water Supply website reports). Therefore, to continue to pump water down the Nepean River would be to waste precious Groundwater.
The Nepean River was in flood over the weekend of 16, 17 June 2007, but the SCA was still pumping water from the Kangaloon Aquifer.
Nepean River running high,
after the flood peak had passed.
Bernard Eddy protested this scandalous waste, directly to the SCA's Bulk Water Manager, Mr Ian Tanner. He also raised this scandalous waste of precious water in public (via radio in Sydney and the Illawarra and Southern Highlands) on Monday 18 January. Finally they stopped the pumping on the Wednesday, (20 June).
For them to claim that they have stopped pumping "to monitor how the Kangaloon Aquifer recharges" is purely Public Relations "spin". As I mentioned above, to use the vernacular: What a crock....???
If the SCA could guarantee to get two "one in ten year" rainfall events, as we have had this season, then, hardly anyone would object to limited pumping of the Kangaloon Aquifer. But, to use this year's rainfall events (and any recharge figures they might produce as a result) as justification for pumping to be "safe" would be totally meaningless.
Accordingly, in accordance with their management of the Upper Nepean Borefield project, so far, I expect that they will make exactly such a claim in the near future.