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.