As the Murray Basin gets another “summit” for it’s troubles it is timely to take a good hard look at the facts behind the last river to get the “can do” swagger from our politicians and environmental saviours. In October 2000 the Feds, NSW and Victorian governments gave us another “milestone” in the great pantheon of environmental achievements. They agreed to return 21 per cent of the Snowy River’s water that has hitherto been captured in the dam system and sent down to the Murray irrigators.
The hype merchants and word molesters were out in force. They had “saved an Aussie icon” and “restored the mighty river to its former glory”. There was no room at all for the fact that these custodians of the public good had just seriously impaired the contributive value and efficiency of a public asset, the dam system and related power generating capacity.
But that is only small beer compared to the character, scale and extent of the gross misrepresentation of facts that had been introduced into the policy process, without any apparent challenge by the professional officers involved, leading up to this decision.
A good grasp of the kind of arguments put by the self-appointed saviours of the Snowy River, prepared by East Gippsland Independent State MLA, Craig Ingram, can be seen here. If this MP has made similar representations to the Victorian Parliament then there are grounds to investigate whether he has engaged in grossly misleading and deceptive conduct.
He informed us that:
“The value of the Snowy River to the Australian people is beyond calculation. Right now, this national icon lies at death’s door. The once mighty Snowy River has been reduced to a series of small, stagnant pools, choked with weeds and sand. Seawater is intruding upstream and native fish are fast disappearing”.
Note the clear implication that river flow is negligible and that this condition is present over the entire length of the river system. This perception was reinforced under the heading “a matter of equity” with the claim that “Australians are asking for 28 per cent of the original flow to be returned to the Snowy River”. And who, one may ask, could possibly argue against an apparent restoration of a river from 0 per cent to 28 per cent of its former flow?
But let’s put this into perspective. This 28 per cent amounts to about 330,000 megalitres or 1.3 times the total volume used each year by the 1.5 million residents of greater Brisbane. It was followed by the claim that, “the water needed for the Snowy can come from efficiency savings in irrigation”.
They quoted Professor John Lovering, former Chairman of the Murray Darling Basin Commission, as saying, “just a 10 per cent improvement in irrigation and farm management practices could deliver one million megalitres of extra water to irrigators”. And then implied that a simple, unstated, back-door, tax-in-kind, of 33 per cent of the farmer’s gross, hard won, efficiency gains, on top of all their existing tax obligations, was all that was needed to fix this “matter of equity”.
No one asked if any other segment of the broader community was being asked to hand over a full third of their gross efficiency gains over more than the next decade. Per capita productivity gains in Australia are generally in the order of 1per cent per annum and those gains are already taxed at between 30 and 45 per cent. But the parties to this water agreement, both Liberal and Labor, thought nothing of taking the first 33 per cent as water tax, oblivious to the fact that the farmers would subsequently be taxed another 30 to 45 per cent on the remainder. The effective tax on these farmers productivity gains would be 55 to 60 per cent.
In blissful ignorance, it was such a simple, seductive concept that it was easily taken up by otherwise intelligent departmental officers, who lacked either the time or inclination to think the matter through.
The Alliance lists as references:
1994 scoping report commissioned by NSW and Victorian Governments. Recognises 28 per cent of the Snowy’s original flow is needed to reinstate the ecological function of the river;
1996 expert panel of scientists conclude that insufficient water is released from Jindabyne Dam to maintain a healthy ecosystem. They recommended 28 per cent;
1998 Scientific Reference Panel of the Snowy Water Inquiry conducted by NSW and Victorian Governments supports a minimum of 28 per cent.
The ACT Environment Commission also gets into the act with the narrow perspective of the Snowy River Shire when it claims, “The scheme diverted close to 99 per cent, or 520 gigalitres each year, of the Snowy River flow into the Murrumbidgee and Murray River system. This left the Snowy River with only 1 per cent, or nine gigalitres, of its average annual flow. A decision in 2002 saw this environmental flow increased to 38 gigalitres each year, or 6 per cent of the total flow.”
But it then includes a very important rider, stating, “No estimate of the volume of water that escapes the Shire in the various river systems, where that water is not captured by the scheme, is available”.
You see, all the claims about absent flows, and so on, have been in relation to the minor portion of the river system immediately below the dams. And both the public, and the policy process, has been encouraged to assume that this applies to the entire river system. But as each additional tributary joins the river on its way to the sea the more “healthy” the river becomes.
Indeed, the East Gippsland Catchment Management Authority provides the first glimmer of evidence that the Snowy system is not quite as bad as it has been made out to be. It has a map showing entirely unmodified tributaries (listed for their heritage values) and a photo of what looks like a very healthy river.
It is not until we go to the Australian Natural Resource Atlas that we get closer to the real story on the Snowy River.
Total catchment area = 1,589,600 hectares
NSW catchment area = 894,000 ha
Victoria catchment area = 685,600 ha
NSW mean annual runoff = 1,317,000 megalitres of which 513,000Ml is captured in dams.
Victoria mean annual runoff = 863,000Ml plus 804,000Ml from NSW.
And this tells us that about 1,664,000 megalitres out of total catchment runoff of 2.18 million still makes it to the sea at Marlo. So we have a river system which has numerous tributaries that still exhibit zero disturbance in normal flows and allow the lower river to still deliver 76.3 per cent of total runoff into the sea.
The claimed requirement for another 330,000Ml, deemed by the above mentioned “expert panels” as the minimum required to restore the ecological function of the river, would send 91.5 per cent (1.99 million Ml) of total runoff into the sea.
Note that there is some discrepancy in the Alliance’s maths. If 330,000Ml is 28 per cent of flow then total flow would only be 1.18 million Ml not the 1.317 million Ml reported by ANRA as the NSW share of the runoff. What we do know with absolute certainty is that no mandate would have been given by the public to undermine the efficiency of expensive infrastructure for the dubious benefits of lifting river flow from 76.3 per cent to 91.5 per cent.
But wait, there is more. The Victorian part of the catchment is still largely timbered so we can assume that the runoff volumes from the Victorian portion are close to the original pre-settlement volumes. The same cannot be said about the NSW portion where, outside of the National Parks and reserves, extensive clearing has increased the runoff volume from pre-settlement volumes.
The Australian Natural Resource Atlas has good, but apparently limited access, data on the extent and type of original vegetation and the extent of subsequent clearing. An exact area is not available but by visual estimate about 66 per cent of this part of the catchment has been cleared. And from this we can make a reasonable “guestimate” at the change in runoff volumes since settlement.
We also know the mean annual rainfall at Bombala is 645mm which is quite evenly distributed throughout the year. This even distribution is also present at Nimmitabel with mean annual rainfall of 690mm. And from the work on 21 Victorian catchments by Holmes and Sinclair in 1986, as reported in Vertessy et al, 1998, “Predicting water yield from Mountain Ash catchments”, we can determine the changes in yield with some accuracy.
Where there is an annual rainfall of 700mm a forest will use 650mm while 50mm is runoff. If you clear that forest to pasture and, assuming it is not overgrazed, it will use 545mm of rain with 155mm of runoff, an increase in yield of 210 per cent.
So when we look at the catchment below the dams and above the state border we find 1/3rd uncleared land that produces 100 per cent of presettlement water yield and 2/3rds cleared land that produces 310 per cent of pre-settlement water yield. And this means that the current runoff of 804,000Ml represents (1x 0.333 + 3.1 x 0.666 = 2.4) 2.4 times the original pre-settlement flows.
Hence, the total pre-settlement flow from both cleared and uncleared land was 335,000Ml while the cleared land now delivers an additional 469,000Ml to the Victorian part of the river.
This tells us that the original pre-settlement flows at the mouth of the Snowy River consisted of;
863,000Ml from the Victorian portion;
335,000Ml from the NSW portion below the dams; and
513,000Ml from above the dams,
for a total flow of 1.711 million Ml.
And that means that the current mean annual flow of 1.644 million Ml is actually 96 per cent of the pre-settlement flow. In effect, all but 44,000Ml of the 513,000Ml that is diverted from the Snowy to the Murray is already compensated for by the increased runoff from clearing in the NSW portion.
But the downstream observers in Victoria only have visual and anecdotal references to river flows that have occurred after the upstream clearing activity has increased flows. And it is this man-made increase in river flows that they are now seeking to convert to some sort of baseline for an environmental duty of care to minimise harm. But if they succeed in getting the existing agreement implemented they will lock in an entirely unwarranted ecological surplus at the expense of the Murray system and the communities that depend on it.
The facts are that the current 4 per cent reduction in river flows is almost statistically irrelevant in terms of the normal range of variation in rainfall and runoff. For example, the 1st decile event for Bombala is only 457mm (71% of mean) and the 9th decile event is 866mm (134% of mean) for a natural range of 66 per cent of mean.
This is not to say that the 30 to 40km of river below the dam is not significantly diminished, it obviously is. But pouring $50 million worth of valuable water into the ocean is a very silly, indeed, incompetent way of fixing the problem. There is a much better way – based on the fact that the one type of water use that is most suited to recycling is water used for environmental flows.
The Snowy River itself does a great deal to assist in the recycling of its environmental flows. It traces a large, 95km, bend in the section concerned that ends only 27km away from where it starts. So the construction of a short pipeline and pumping system would enable the release of just a single day’s worth of environmental flow which could then be pumped back to the starting point (recycled) to do the same job each day for the next 364 days each year.
This would take place before the steep drop onto the Victorian lowlands and the countryside that the pipeline would need to cross is already cleared with comparatively mild undulation that is well suited to pumping and syphoning.
The key to the feasibility of this sort of recycling of environmental flows is; can we pump a megalitre of water along a 27km pipe with modest head for less than the price that a farmer would pay for the same megalitre? Clearly, the answer is an unambiguous “Yes”.
Adelaide pumps its water 170km from the Murray River, and over a hill, presumably at an acceptable wholesale price.
Farmers in the Brisbane Valley are eager to pay for recycled Brisbane sewerage that will be pumped more than 60km.
The plan to reintroduce recycled water into Wivenhoe Dam will involve a lift of more than 100 metres and more than 40km of pipeline and be reintroduced to the urban water system at a profitable margin on a wholesale price of $170 per Ml.
So even if there was a sound case for restoring flows to the Snowy River then taking good water out of the dams is not the best option. The Greens’ target of 330,000Ml in water savings could be ploughed back into more production that will inject $132 million into towns on the Murray each year. A modest pumping load of 100Ml a day would deliver 36,500Ml of river flow to the actual section of river that needs it while leaving 36,400Ml for farmers to add $15 million worth of crop value to the remainder.
For the moment, the most inefficient water users, and those most reluctant to adopt new ideas, technology and innovations, are the Green movement and their captive departmental minions. Unlike sewerage or storm water recycling, water that is released for environmental flows needs no expensive processing to enable it to be used again, and again. And this capacity for multiple recycling gives it an entire order of magnitude greater priority than all other water efficiency options. We all need to get a lot smarter with our use of water but our self appointed environmental guardians have a lot further to go than anyone else.
More importantly, neither the federal government, nor any of the state governments would be complying with our well defined principles of “proper exercise of power” if they continue to try to develop catchment wide water allocation policies without taking the highly relevant factors of clearing induced changes in water yield, and the potential for recycling environmental flows, into account.
To continue to do so in the face of such overwhelming scientific evidence would not only be grossly negligent but may also constitute criminal conspiracy. It has to stop.
Ian Mott,
Byron Hinterland
Australia
———————–
Ian Mott is a third generation native forest owner, miller and regenerator from the Byron hinterland.
A former Sydney and Brisbane Executive Recruiter with his own agency, his interest in the family property has seen him evolve, over the past decade, into a property rights activist and consultant. He is secretary of the Landholders Institute Inc and has held a number of positions on national, state and regional level policy and planning bodies.
A version of this article was first published at On Line Opinion on 23rd November 2006.
Jennifer Marohasy BSc PhD is a critical thinker with expertise in the scientific method.
Only question I have is the amount of clearing done post 1788 in NSW.
Captain Mark Currie RN, who was on the first European expedition to the South of the Colony, report back to the Gov that the “Maneroo Plains” were rolling hills and downs with rich grass, strangely treeless.
One of the reasons for early settlement of the area was that the squatters didnt have to clear the land.
This has been put down to cold air pooling in the valleys ie frost hollows, which kills off any native tree seedling.
Try http://www.cooma.nsw.gov.au/culturemap/
Like the idea of recycling environmental flows.
Could always power it by a wind farm or two on the ridges above Paupong and Ingebirah
Ian – a prodigious outing for your envelope.
Let me say at the outset that if people don’t care about the health of the Snowy River, consider impacts are over-rated, or think it’s cost effective to let it languish for Murray River production purposes then discount what I’m about to say.
A bit of research on the Snowy has turned up with this potted summary .. .. ..
“The Snowy River originates on the slopes of Mount Kosciusko in south-east NSW and falls steeply for about 30 km to the Monaro Tablelands where the river has cut a deep valley. The river then enters gorge country until reaching the river flats and mouth at the Victorian coastline. It is approximately 500 km long with a catchment area of about 15,500 km2. The climate is alpine in the north-west, coastal in the Victorian flats and cool temperate elsewhere. Mean annual rainfall varies considerably over the catchment with up to 2,000 mm in the Snowy Mountains to less than 500 mm in rainshadow affected areas around Dalgety.
Most of the alpine country in NSW and Victoria is national park. The parks provide for a wide range of recreational activities, support the majority of Australia’s ski industry and include significant declared wilderness areas. Summer grazing of alpine areas has been progressively withdrawn due to environmental and water quality concerns, and was excluded from Kosciusko National Park in 1969. Grazing dominates land use on the tablelands, much of which has been cleared of the original dominant snow gum woodland vegetation. There has been little pasture improvement as agricultural production is limited by the cold winter climate and, in much of the region, poor soils. Forestry occurs in both native and plantation forests in the eastern area of the catchment and the rich alluvial flats in the south of the catchment support intensive cultivation.
Prior to the Snowy Mountains Scheme, flow conditions in the Snowy River were characterised by peak discharges in spring due to melting snow. The river experienced highly variable flows and rapid fluctuations in levels due to high precipitation, intense rainfall events, low evaporative losses and steep rocky terrain. Floodwaters moved rapidly down the catchment with relatively little attenuation due to the gorge nature of much of the stream valley. The rainshadow effect in the tablelands results in this section of the catchment being largely dependent on the alpine areas for river flow.
The development of the Snowy Mountains Hydro-electric Scheme during the 1950s and 1960s has had a profound impact on the hydrology of the Snowy River catchment.
The major visual impacts of the changed flow regime can be found in the channel of the Snowy River between Jindabyne Dam and the junction of the Delegate River. The channel has dramatically contracted in size and has become overgrown by vegetation, mainly exotic blackberries and willows (Finlayson et al. 1994). This complete change in channel morphology and external input can change the composition of the entire aquatic community in this reach of the river.
There have been numerous reports of increased salinity in the lower catchment both in the main channel and on the flood plain at the mouth of the river. Irrigators and land holders estimate that the saline wedge associated with the river mouth has progressed from approximately 10 km to 17 km upstream as a result of the increased frequency of low flows. The Snowy River Interstate Catchment Coordination Committee (SRICCC 1993) reports that increased salinity in the lower Snowy is affecting about 550 ha of farm land causing a loss in agricultural production in the order of $4M annually.
SRICCC (1993) reports that reduced frequency of flushing flows has increased sediment in the lower Snowy River and reduced the number and depth of water holes thought to be critical to breeding for Australian bass, though there is conflicting evidence about sedimentation characteristics since the construction of the scheme.” .. ..
So (a) the river ecology and morphology has changed dramatically since the construction of the scheme not matter what envelopes say
(b) it’s not about averages – it’s about peak events – these peak events seem to have been provided by the Snowy Mountains area, snow melt, and high rainfall events. Not by the entire catchment. Your flushes were coming from the now captured Snowy Mountains part of the catchment.
(c) having a nice like recycled canal isn’t going to restore river ecology, channel features, nor address salt issues – it will simply be a just a nice garden water feature.
(d) Monaro tablelands have been drought central over last decade – hope your averages are AGW proof.
(e) if you want to convince any ecologists you’ll have to work through to number of peak flow flushing events
(f) I’m not convinced how much soil depth you’ve got to distinguish between grass and trees hydrology responses over those areas – but I don’t have the numbers either
Nice try though – have another go considering the essential elements needed for the river ecology. Of course if the attitude is bugger the river – production is more important than what greenies want (add spivs, scum etc to flavour as per taste) then don’t bother. I can appreciate the argument.
Readers will have to excuse Luke for his comprehension deficits. Even his own posting recognised that the most affected area is upstream from Delegate but then seeks to imply that the entire river is stuffed. The further down stream one goes the more the clearing induced water yield compensates for diversions into the dams.
More interesting is his blatant hypocrisy. He has previously provided links to well tested models like REALM on water yields in victorian catchments, by Weeks et al from the CRC for Catchment Hydrology, but starts ducking and jiving when the same methodology is applied to a green sacred cow.
His point ‘b’ claiming ‘it is all about peaks, not averages is further evidence of poor retention skills. He ignores the key point that peak flows can be delivered to a section of river just as economically as average flows.
AS LONG AS THE WATER CAN BE PUMPED ALONG THE RETURN PIPE FOR LESS THAN A FARMER OR OTHER USER WOULD BE WILLING TO PAY FOR THE SAME VOLUME, THEN ECOLOGICAL FLOWS CAN BE RECYCLED FOR A WIN/WIN RESULT.
And in answer to your point ‘c’, restored flow volumes will most certainly restore channel features and river ecology to the part of the river it operates on.
The question then becomes one of, is 500 hectares of salinity creep at the river mouth worth 500,000 megalitres or $300 million a year in lost production to maintain? That is, $600,000/ha/year?
These sorts of river mouth impacts are routinely painted as a drastic and permanent loss of habitat when, in fact, it is nothing more fearful than the movement of the boundary between two ecosystems. And in most cases that boundary between saline and fresh water ecosystems has always moved up and down the river depending on whether the year has been a 1st decile or 9th decile rainfall year.
The best example is the fact that the generally modest but intermittently mighty Murray used to be tidal at Morgan SA. But ever since the Barrage was put in place, that never actually delivered any decent water to Adelaide, that entire stretch of river is now treated as an ecosystem that must be RESTORED TO SOME ENTIRELY IMAGINARY PRISTINE FRESH WATER CONDITION.
So we are seriously expected to cry tears of blood for a partial, seasonal salinisation of 10km at the mouth of the Snowy River while a 200km stretch of the Murray has been converted to fresh water by the same water managers.
But of course, any excuse to shaft a farmer in the middle will do, won’t it?
Readers will note Ian’s typical groin-kick style as way of saying hello. Readers might also note this is why Ian doesn’t do well in discussions with guvmint anymore as extreme rudeness doesn’t make a good basis for discussions. Although some people are probably immune by now. Instead of doing the nana coz you know I’v made some reasonable points try a discussion for a change.
I have said at the outset if one values the irrigation dollars more than the Snowy well stop at that now. As for the Murray – it’s essentially an irrigation ditch.
I’m know about trees and catchment hydrology and the section (a substantial section) of the river being discussed. Yes the salinity issue is small economic beer as comapared to the value of the water. I’m not hiding or denying any of the priors.
The point remains that the source of the flushes are from the Snowy area and from shallow soils not as you describe it. You have not addressed the ecological needs for peak flow type flushes. Having a nice little recycling pump and converting a stretch of river into the lower Yarra is not what the watercourse is about.
Anyway I have made my observations. You are not going to think about it. So typical of this blog nobody changes their views or attempts to build an agreed debated position. It’s just all or nothing.
But why not simply say the economics of the value of the irrigation water overwhelm the needs of the Snowy River. It simply ain’t worth it. Easier than playing pseudo-ecologists and terra-formers.
(Try not saying scum or spiv when you’re convincing the relevant authorities Ian – it may detract somewhat from your message).
Luke, there have been two posts on this thread that have included the words scum and spiv, BOTH OF THEM YOURS. Most observers would conclude that your first post was an attempt at goading me into using invective. They would also conclude that your second post was an attempt at implying that I already had.
But still so little of substance from you, Luke.
On the issue of seasonal peaks, you would discover, if you thought about it for a moment, that snow does not completely melt on the first day of spring. It does not all flow away in a week or even a month. It can take more than three months before the last snow on shaded south facing slopes has melted. And this means that the seasonal flushing of the river system also takes this long.
And that means a single days flow volume can generally be recycled about 90 times each year to achieve the required seasonal volume.
Your unsubstantiated doubts on the soil characteristics in the catchment and the concentration of snowfall in the national park are green herrings. The catchment where the landuse change has taken place is what you called the Monaro Plateau. So what grounds would you have for concluding that this plateau has the sort of thin soils that would render the yield models invalid?
Furthermore, the area of the park is also small when compared to the rest of the NSW part of the catchment. The NSW portion is 894,000ha with 513,000Ml from above the dams and 804,000Ml from below. So if parts of the Park above the dam is getting a 2000mm annual snow/rain fall then the net runoff is likely to be about 15Ml/ha which would come from only 34,000 hectares.
I don’t have the actual area of Park within the catchment but as a rough guestimate this would leave about 860,000ha that would only need to increase water yield by 0.6 of a megalitre to equal the runoff from the park. This outcome is well within the range of results for catchments with similar characteristics, especially snow fall etc, just over the border.
And it must also be pointed out that you appear to be assuming that very little of the annual runoff from the Monaro Plateau coincides with the snow melt. This area also includes other mountainous areas outside the park so are you implying that these mountains don’t ever get snow?
My purpose in posting this article on this blog was to ensure that it got a thorough testing. But that hardly seems the case to date. Perhaps you could ask someone else in your department to give it some thought? Preferably one capable of using a calculator.
Come on Iansy-weensy – don’t upset about scum and spiv – was just trying to be like you and make you feel at home. Humour – smile. My little homework above says most of the flushes come from the Snowy part of the catchment as peak discharge events (high rain and/or snow melt combos). And that the soils in these areas are poor. I didn’t say that the models are invalidated there – soil water store/availability is an issue that can affect the maths. So do some homework and invalidate my points and you have a case.
You also need to do some background on recent Monaro climatology given it seems to have become drought central. Of course if you don’t think “recent” matters so be it.
But we don’t want nice steady gurgle gurgle little stream – we want whooosh – a big flow event. Well that’s what the anecdotal history says. If you were scholarly (which we know persons with and envelope have no need for) you may have done some background reading first.
I don’t have to “invalidate your points”, as you claim, Luke, because all you have made are generalities with nothing specific that could be even examined, let alone validated.
And for the record, recently half of Australia “seems to have become drought central” as you put it, but that is no basis for disregarding the rainfall records as a basis for catchment water yield assessments, as you seem overly eager to do.
And spare us the pathetic “gurgles and whoosh”, if the water can be pumped 27km for less than the market price of that water then it can be recycled as either a gurgle or a whoosh.
The more pathetic your points become, Luke, the more you expose your ideological bias. Lets face it, you just can’t get your departmental brain around the idea of delivering ecological services with engineered solutions.
OK – well your idea is flawed then if your don’t address the fundamentals which are:
“Prior to the Snowy Mountains Scheme, flow conditions in the Snowy River were characterised by peak discharges in spring due to melting snow. The river experienced highly variable flows and rapid fluctuations in levels due to high precipitation, intense rainfall events, low evaporative losses and steep rocky terrain. Floodwaters moved rapidly down the catchment with relatively little attenuation due to the gorge nature of much of the stream valley.”
I don’t think you actually have the intellectual ability to reason with so last time I waste anytime on pompous windbags. As I have always said – get 100 votes in an election and we may look up briefly. Last comment.
Thanks for raising the pre-settlement vegetation issue, Allan. At this stage we can only go on the Land & Water Audit data that claims significant clearing. But even if most of the upper catchment was grassland there would still be an increase in runoff since settlement because the more intense grazing regimes would have reduced the leaf area index of the pasture itself.
Luke, such flood surges can be delivered by the simple addition of small on-stream or off-stream storages at top and bottom that would allow for up to a week of pumping for a sudden weekly release. This could then be captured in the same size storage at or near the collection point and returned to the top over the following week for the next release.
Your quoted post has no detail on the actual volumes in these flood events. You have discounted the idea when armed with nothing but generalities and have made no attempt to get close enough to the problem to actually understand the dynamics. Your little green vaudeville routine is looking a bit tawdry, don’t you think?
* As I have always said – get 100 votes in an election and we may look up briefly.*
Get a majority and you will stand to attention!
What is the point in having a big, circular stretch of water? That just means it’s not a river any more.
SJT, I understand your question but it is not a big circular stretch of water, it is a loop that involves part of the flow while other tributaries feed the rest of the river.
In the case of the Snowy, the loop starts about 45km up stream from the Delegate tributary and ends about 45km below it. So if the equivalent of the entire volume of flows from above the dam was recycled in a loop below the dam then the part below the Delegate junction would actually enjoy above normal flows. This would continue until the collection point where the loop would recycle it’s water and the Delegate water would continue downstream.
Most of the increased run-off from clearing is delivered to the river via the Delegate tributary and as this is almost the same volume as the captured volume up stream, the river flow into Victoria would remain close to the historical norm.
Recycling environmental flows is most effective in the river portions that are most affected by the Dams, ie, immediately below them.