A very complex article from the native forest logging industry. What's it like to fell red cedar? How much does felling a 400 year old tree yield?

"The facts are that a 4 per cent reduction in river flows is almost statistically irrelevant in terms of the normal range of variation in rainfall and runoff. This is not to say that the 30 to 40km of river below the dam is not significantly diminished, it obviously is. "

Which tends to demolish your extensive statistical argument. LOL

"But pouring $50 million worth of valuable water into the ocean is a very silly, indeed, incompetent way of fixing the problem..."

Still don't get this 'environment' thing at all, do you? The increase in volume of water going down the river aids native fish, reduces toxic algae, improves water quality for downstream users, flushes estuaries and feeds fisheries.

Just because you can't find such entries on your accountants spreadsheet (tip: they're not in the My Profits column, and are not usefully quantified in $) doesn't mean they aren't real. It just demonstrates why accountants make very bad scientists and policy makers (but kudos for going through the numbers in public anyway).

PS. I support the call on your Landholders Institute Inc page for re-establishment of perennial native grasses, but you might want to update your climate change denial link (Lord Monkton is popular just now). Just FOI, is the Landholders Institute Inc still nestling in the IPA's pocket with the Australian Environment Foundation?

The author ignores that pre-settlement the Snowy River received significant inflows from the annual spring snow melt (high run-off, high volume), which came from the mountains, where annual precipitation exceeds 2000mm. This annual flush of water created a unique river ecology. Lake Jindabyne largely eliminated that flow – a much larger and more reliable one than run-off from the down stream catchment (which lies in a rain shadow with notoriously sporadic rainfall) – so altering the river ecology. Nonetheless, the Snowy River has been starved of its pre-settlement flow for so long that the ecology we see now is endemic.

My main query is, "Why is it that the Snowy flats at Orbost do not seem to have had a significant flood in recent years since the dam at Jindabyne was built?" Perhaps the previous post is the answer. There seems to be a problem with the arithmetic somewhere.

Robg, Your claim that the Author, ignores pre-settlement spring snow melt (high run-off, high volume), suggests you have some sort of retention deficit. He specifically measures this 513,000 megalitres and points out that subsequent land clearing below the dam has delivered almost enough water to replace this volume.

And the article does recognise that the annual flush has been limited but your claim that the down stream runoff is "notoriously sporadic" is in direct contradiction to the rainfall data at both Bomballa and Nimitabell which shows an even distribution.

And you appear to have missed the key point, that any flows that are required in the upper part of the river can be provided by a much smaller volume of water that can be continually repumped back to the starting point below the dam.

As long as the cost of pumping the water is below the market cost of that water then any volume of water can be recycled in this way at a profit.

So for Liam et al, let me spell it out for Ian. If a megalitre of water that a farmer currently buys for $100 can be recycled by pumping at a cost of only $60/Ml then the community is best served by continually recycling a small volume and continuing to sell the rest of the water to the farmer.

And if it is determined that the upper part of the river needs an annual flush of 300,000 megalitres over a period of 100 days during spring/summer then that need can be delivered with only 3,000 megalitres that is recycled 100 times.

And that 300,000 megalitres of benefit will be delivered at a cost that is, in the above example, $40/Ml (40%) cheaper than the dumbest option of sending the farmer's livelihood down the great gurgler to the sea. It is a win for the farmers, a win for the environment, and a win for the continued efficient operation of the snowy system.

Perseus,

the point I tried to make relates to the flow distribution and flow rate of water, not the total volume. Much of the 513,000ML pre-settlement would have been delivered over a period less than 3 months (October to early December snow melt). This is not the same as releasing and pumping back 1405ML per day over a year. Neither does the present downstream catchment compensate for a flow of this nature. Regarding the downstream catchment area rainfall: though the average monthly rainfall is even, it doesn’t mean that amount falls every month every year. That is, it tells nothing about rainfall variability, which happens to be high compared to precipitation in the alps (see http://www.bom.gov.au/cgi-bin/climate/cgi_bin_scripts/variability.cgi ). But really, the benefits of the Snowy Scheme in terms of power production and food production are great compared to a river ecology that has been irreversibly changed anyway.

The massive hype surrounding the Snowy, environmental flows and economic impacts are once again seemingly being assessed and acted upon by those who have overlooked certain obvious parts of the Snowy Mountains Hydro schemes inception. All the information that seems to be available is that the Jindabyne dam was created to facilitate electricity production, along the way , irrigation became fashionable to those along the Murray system and the increased usage of the drawn off water for agricultural production to the West has seen a dramatic reduction in the Snowy River quality. There are farmers and producers who use / used the water from the Snowy but their numbers are declining in line with the decreased viability of irrigation availability from the lower river reaches. Anyone who wishes may visit our house at the ocean mouth of the Snowy and sit and watch it once again silt closed.

So, Achis, are you claiming that the National Land and Water Audit data is wrong?

This anecdotal stuff about the mouth being silted up is really dishonest. Given the nature of the catchment and the nature of the rainfall in most of it, there is not the slightest doubt that the mouth of the Snowy was always silted up for part of the year in presettlement times.

Those times would certainly include late November after the spring melt is over. So what you people have been saying about silted river mouth is downright fraudulent.

What I would like to see from the proponents of this Snowy "restoration" scam is a list of all the aquatic species that are found, or were found, in the Snowy or Mitchell rivers. And then please identify the species that have actually died out in the Snowy after 40 years of captured snow melt but still remain in the Mitchell.

Come on folks, give us some real data to work with?

What a drongo you are Perseus, its only industry funded front groups have the resources for that sort of research! Why do you think the Federal government has been defunding CSIRO L&W and the ENGO's for ten years, but to stem the flow of inconvenient facts.

Incidentally, do you run cover for ALL the Institute for Public Affairs offshoots that post to OLO? Your expertise on climate change, hydrology, forestry and engineering is indeed impressive (chortle).

Gee Perseus, when contributing an opinion to this forum, i hardly expected such vitriol, but never the less, I will take it on board. I am not, as some may assume, a member of any conservation , farming or industry group. I do not earn a living from agriculture, or in any particular way gain anything from the Snowy River other than catching the occasional fish for a meal and relaxing along its banks and tributaries. All I know as far as the history of the Snowy goes is that there used to be shallow draught, sea going vessels navigating its reaches to near Orbost, some 15 klms upstream of the mouth, from anything I have read or seen in photographs, this activity used to be a year round occurrence, with the mouth only ever closing over in years of extreme drought. These days the degredation of the river has lead to frequent closures and even at the best of times in the terms of river flow it is near impossible to get my 3.8 m boat much further than 1/2 way to Orbost. Given that my personal experiences of the river go back to the early 70's, I refuse to be told that people are manufacturing claims about the health of the river for nothing other than personal gain, I have seen many changes occur and they are of a whole, totally in line with the claims being made about the river health.

So tell me, Achis, what, exactly, in my previous post would you describe as vitriole? Describing something as a scam? Surely you wouldn't be trying to defame me by anny chance?

I could name you a number of rivers without major dams that used to be navigable a lot further than they are today. In those days they had the good sense to go up with the tide and use local knowledge of seasonal conditions. Even the Darling River once had a port at Burke, NSW but they ceased using it long before any dams were built.

So is your little anecdote based on high tide or low? And best check your facts on the time of the year when this navigation took place. And your implied claim to have no vested interest is a bit rich. You just want all that water to landscape your front/back yard.

So much detailed research and vitriol being expended on head-butting absolutely anything with a hint of green about it ! We are witnessing a number of extraordinary outbursts against all forms of conservation of our environment on this web site - don't know if the same is happening on others as well, don't have time to do the survey but someone should.

Wonder who's paying ? and what vested interests might be behind a lengthy critique of one small effort to restore just one iconic river in this country. Anyway the obvious increase in temperatures which we are experiencing will cause further desiccation of catchments and river systems in our poor dry continent - wonder if that is taken into account by I. Mott & co. ?

And Kang, so little of substance in reply by yourself and others. Can I assume then that you do not doubt the official stats on water flows in the snowy catchment? Good, at least we are one step up from a flat earth.

And Liam can't do any better than a bit of abuse. Being called a drongo by the Kangs and Liams of this planet could only be regarded as a badge of honour amongst reasonable men and women. And no fellas, I am not even a member of the IPA so if you really want to treat your paranoia you should put your bong away and stop smoking the hydro.

Ian Mott has shown very clearly that if East Gippsland Independent State MLA, Craig Ingram, wants "...28 per cent of the original flow to be returned to the Snowy River” then his wish has already been granted. Mr Mott shows that "the current mean annual flow of 1.644 million Ml is actually 96 per cent of the pre-settlement flow". No one has shown any error in Mr Motts' calculations. It is not a question of being for or against the environment. It's a question of being able to add up.

Maybe Perseus can help me. I am having trouble understanding what an 'annual flush of 300,000 megalitres over a period of 100 days during spring/summer' is supposed to achieve. My simple-minded approach suggested to me that something is being 'flushed' through the river. However, if the flush is being achieved by 'only 3,000 megalitres that is recycled 100 times' then surely that last 3,000 megalitres is going to be something to behold?

Why dont we just build the rest of the Bradfield scheme the rest of the top end water projects.

Then we could send some extra down to the snowy.

It would be great work for the long term unemployed and immigrants.

I suppose he could have been a bit clearer, Eljayel.

What would happen in nature before the dams was that 513,000 megalitres from melting snow would take about 100 days in Spring and early Summer to melt and flow down the river. And this would average about 5,130 megalitres of flow each day.

So if the expert panels have decided that the part of the river below the dams, but above most of the tributories that still deliver water to the river, needs at least 300,000Ml of the original 513,000Ml to restore the flow of this part of the river for the normal 100 days when it used to flow, then that works out at 3,000Ml of flow each day.

But when a pipeline and pump is used to return each days flow to the starting point it means that the first days flow of 3,000Ml can flow back down on the second day and again every subsequent day until the 100th day when the total volume of 300,000Ml of flow has been achieved.

In reality, once the seasonal peak flow has been achieved the daily volume in circulation can be reduced to conform to the normal natural flow and continue to be recirculated for the remaining 265 days at 1,000Ml a day to bring the total volume of river flow to 565,000Ml (ie 265 days x 1000Ml + 100 days x 3000Ml = 565,000Ml).

In such a case, the total flow under recycling could actually exceed the pre-settlement flow volume but only require the actual use of 1,000Ml. All the rest of the water in the dams could then be used for urban or agricultural use.

As long as there is a willing buyer for all the water that is saved in this way, and the price they pay is high enough to cover the cost of the recycling pipeline and the cost of pumping, then there is no reason why a much higher portion of catchment flows can be captured in Dams for other use.

I don't want to be rude, Perseus, but did you actually read my post? I have read the article, and the posts. I asked about the purpose of the 'flush', i.e. What does the annual flush achieve? My worry is that, if it actually flushes something from the river, then I don't see how pumping the 'flushed material' around the same stretch of river 100 times achieves anything at all.

Eljayel, you appear to be taking a literal interpretation of the term "flush". A seasonal flush is merely a term for a seasonal increase in flow. So such an increased flow through recycling water numerous times will merely duplicate what the melted snow does.

Furthermore, the water is clean at the start and is generally just as clean, if not cleaner, when it is recaptured down stream. But if one tried to do this sort of recycling with certain third world rivers that are essentially used as open sewers, then I agree, the last cycle certainly would be something to behold, as you put it.

The Pearl River in Gwongdung, the Ganges at Varanasi, the one in Bangkok and some of the less salubrious reaches of the Parramatta and Yarra come to mind.

That is not the case with the Snowy River and it is highly unlikely that there would be many rivers, or parts of rivers, in Australia that would have pollution levels that would preclude this sort of recycling. And even if there was, the regular capture of the flow would facilitate the application of both active and passive filtration systems etc to the cycle prior to reintroducing the water to the river.

Generally, the flow of water in the upper reaches of river systems will actually improve oxygen levels as it drops over small falls etc.

thanks Perseus, that seems pretty simple. But if the flush does nothing, then why do it? It seems a huge waste of resources.
Of course, if it was necessary, then filtering would solve the problem of waste build-up. I suppose it is easy to filter 3000 megalitres a day.

The reason for the flush, Eljayel, is that some of the species that live in the river have evolved to complete part of their life cycle when the river is flowing well. Most can still get by on reduced water flows but if we can find ways to meet the needs of both wildlife and farmers at the same time then we certainly should consider it.