Louis was perhaps somewhat baffled by my recent post on salinity. A reader of this weblog who lives closer to the issue sent in this comment from ‘The Ringer’, Download file. It perhaps provides an additional perspective.
The Ringer suggests the random red splotches on that map are just as controversial and costly to tax payers as the National Gallery’s Blue Poles.
And all this reminds me of the ‘National Land & Water Resources Audit Australian Dryland Salinity Assessment 2000’ which appears to provide detailed statistics on the extent and magnitude of our salinity problem. But on careful analysis it is evident that the document always presents a prediction – even when data is presented for 1998. The entire document is concerned with ‘hazard’ and ‘high risk’ without providing a single statistic indicating the actual measured extent of dryland salinity.
And then there is the ‘National Land and Water Resources Audit Australian Water Resources Assessment 2000’ which is also meant to provide salinity information. However, without presenting a single trend line for any water quality indicator, the report purports to provide, “the first overview of Australia’s declining surface water quality with salinity, nutrients and turbidity issues revealed across most of the intensively used basins”.
Jennifer Marohasy BSc PhD is a critical thinker with expertise in the scientific method.
Jen has simply noted, as a scientist trained in the Pre-Whitlam era, I am lexically and conceptioally challenged by the post modernism dominating science these days.
Aw come on guys. WA is not that far away. Come over here and we will give an eyeful of salinity and I’m sure a number of hydrologists would be prepared to let you look at their data. They’ll also probably give you the impression that the situation is highly variable and very complex, and the possible solutions are many, varied and contentious.
I don’t know if maps covered in red are useful predictors of future expressions of salinity or not. Prediction is always complex and mathematical modellers in all fields seem to end up thinking their models are the world, instead of models being useful tools to help understand the world. A mathematical model of gravity may not be perfect, but you can’t deny the existence of gravity itself.
I suspect the reason why a lot of borehole data doesn’t make it into these “state of the nation” reports is that the data was published, discussed and interpreted decades ago. It’s good that you want to see it; scientific review is healthy, but it just doesn’t seem to rise to the lofty heights of Canberra-level reports any more.
Analogy; a discussion about the effect of speed on road fatalities doesn’t review the physics of mass and acceleration behind the understanding that hitting an oncoming laden triple-trailer road train at a combined speed of 210kph is more damaging than hitting an oncoming frog at a combined speed of 115kph. Unless you happen to be the frog.
If you want that level of detail, you need to ferret out the data for yourself. None of the journals would now bother with a paper that goes back so far. Scientists can’t be expected to review the history of 80 years of data and analysis every time they write up their current research. The first recorded example of water table rise and secondary salinity in WA was in the 1920s, when a railway engineer investigated the corrosion of locomotive boilers or something like that. And Mundaring Weir, which supplies Kalgoorlie with fresh water from the hills behind Perth, was partially cleared in the 1920s to increase streamflow. The river went saline, they let the forest recover and the river became fresh again. The Middle East is full of somewhat older examples. We’ve been over this before, at least twice.
Secondary salinity is like gravity, it happens. It’s not some global warming prediction that may or may not come to pass for any number of partially understood reasons. Salinity’s real and expanding. Maybe the Murray Darling Basin is not the same as the WA wheatbelt, but you had better hope it is quite very very extremely different if you want to argue that salinity is another government scientist propagated conspiracy.
Ahhhhrrrrrrrr! Slam!!! Jeez f…….. Christ! You must get out more! Now look! You’ve made me punch my monitor!
Rick,
well put.
And where does the salt come from?
Rick, Not denying your problem in WA. But that doesn’t mean SW Queensland is going to go the same way. Indeed you a dealing with a different rainfall pattern, geology and hydrology – though there is definately lots of salt in the profile.
If you look at the earlier post and Tunstall and Jone’s work they suggest the rising bucket model is not necessarily applicable everywhere in the MDB.
And why make predictions about how it was and not then check that prediction – and how can a definitive work on water quality provide no data.
Is your salt problem still getting worse?
BTW I would have thought an audit was the opportunity to review 80 years of data.
The salt primarily comes from rainfall – the ocean. The average saltfall is a few kg per hectare per year, multiplied by the period since the last ice age and you have thousands of tonnes of salt per hectare in a large proportion of the landscape. In the pre-european state of equilibrium there was commonly a balance between saltfall and salt export via streamflow.
My hissy fit is just frustration. While we have the problem before us, and getting worse, the national debate about the likelyhood of salinity becoming a threat is a waste of our time. Maybe not a waste of time in other environments, but we want to get on with it. Meantime Canberra plays politics, trades of states one against another and so on. It’s weakness of our federal system, that serious problems in one area are not percieved to be a problem until its demonstrated to be relevant to the rest of the nation.
Your arguments, are to my way of thinking, a distraction because they are local discussions that occupy the national stage. They are valid debates for you to have in SW Qld, but the nature of national politics (this blog being part of that national debate) means WA has to wait patiently until Lake Burley Griffin goes saline.
I am not deeply involved in the literature and I don’t know the details of Tunstall and Jones’ work, nor have I closely studied the audit. My strongest recollection of it is that, in WA, areas that had the most borehole data (i.e. the southern WA wheatbelt) had the most dire predictions for the next 50 years. Is that because more bores have gone in where the problem first expressed itself? Or would the east and northern WA wheatbelt be covered in more red if there was more borehole data? The catastrophe has been unleashed. 10% of the landscape is salt affected already, predicted to rise to about 30% in 50 years, before many water tables have stopped rising. What about the 200 year forecast? What does it matter if its 27% or 33%? Even 10% is too much. All our rivers that arise in agricultural areas have become unusable due to salinity. If you are confident this won’t happen to the Murray/Darling, fine, but the MDB is not Australia, it’s one corner of it.
In broad terms, you often promote the argument that the government scientists form a club driven by a communal self interest, whereas a private scientist with a product to promote in the emerging salinity marketplace is credible because he/she is not a corrupt government scientist. We all have vested interests, including the pecuniary ones. All scientists should be subjected to the same level of scepticism.
If there is a conspiracy amongst the government scientists, why don’t I hear a uniform opinion amongst them about how to tackle the problem? There are quite strong, even bitter, debates within the government “salinity industry”. This is not the sign of a very effective conspiracy.
Rick,
Sounds like you are applying the same rules that the ‘believers’ apply to the ‘climate change’ discussion – if you question you are into conspiracy theories and/or denial.
What about some discussion about the specifics. Why is it that the situation is getting worse in WA – and how much worse? Why isn’t there a problem in SW Queensland despite the predictions? What should be done that isn’t being done in WA?
The salt comes from rainfall?
I use rainwater exclusively in the bush for drinking- but there is liitle to no salt in rainwater, so this explanation fails. (The means by which we obtain distilled water is to evaporate it, leaving the salts behind).
So where does the salt come from? Clearly the subsurface or below the soil. Has anyone performed a rigourous study of salt distribution in the regolith on a continental scale? I doubt it because the eco-nazis would prohibit any ground disturbing activities, thus hampering scientific efforts.
It is physically impossible to evaporate salts with water and rainwater does not contain salt.
There is no doubt that salinity research costing $100M’s over the past 15 years has been a monumental failure because public scientists are locked into a groundwater rising model that is fundamentally flawed. This is the great science tragedy of the past 50 years in Australia.
Research by my company, ERIC, concluded that increasing salinity was caused by soil degradation. Many other scientists (eg. Christine Jones in the Great Salinity Debate, Australian Farm Journal, in 2000) and farmers have come to the same conclusion. This degradation takes on many forms including compaction or hardpans that degrade soil structure, loss of soil organic matter and carbon, loss of soil biology and native perennial grasses. This degradation reduces deep soil water percolation and increases lateral flows and the ponding of water, often in low-lying areas. Also, the loss of soil health and buffering mobilises salt in lateral flows that concentrates salt in natural pathways. This change in soil health and hydrology is at the root cause of salinity, not rising groundwater as promoted by public agencies. This is why public agency solutions are not adequately addressing the cause of salinity, only symptoms.
ERIC has developed a soil salinity mapping technique using radiometric data and applied it successfully in many states of Australia. Information on this technology is at http://www.eric.com.au/html/product_assessment.html under the heading Dryland Salinity. This provides the evidence that salinity is a soil issue and that salt moves laterally through natural pathways. Soil degradation has exacerbated this flow by increasing the inputs of salt that is normally tied to clays in soil.
The Commonwealth Department of Agriculture, Fisheries and Forestry (DAFF) has recently released a 2005 Spies and Woodgate Report on salinity mapping methods and an ERIC evaluation of the science in this report is at http://www.eric.com.au/html/news.html
In response to posts by Rick, there are a number of his assumptions that need to be challenged. Other issues are addressed below. Firstly, the piezometer bores are a waste of time as most pierce the clay layers or aquitards that stop deeper saline groundwater from rising. Any bore drilled through clay layers or rock will present a raised head, often within 10m of the surface, even though the groundwater was first encountered many 10’s of metres below this level. Piezometer bores are an artefact of the groundwater rising model and irrelevant to salinity assessment. I suggest that Rick read Sally Paulin’s book on Harry Whittington, a WA farmer who proved in the 1950’s that the rising groundwater model was flawed for WA salinity.
The key climate issue for salinity is not rainfall but the windblown sands of the last ice age that redistributed or reworked massive amounts of soil materials (sands, parna and salt) across southern Australia, where most of the saline areas now exist (ie, pre European). If rainfall was an issue we would have high salinity on the coastal zones of eastern Australia.
Generally, there are several issues that are being confused by the public science rhetoric. These issues can be posed as questions:
1. Is dryland salinity associated with changes to soil water regimes (due to soil degradation)?
2. Are changes to soil water regimes necessarily associated with changes to water tables?
3. Does rising groundwater bring salt to the surface?
4. Is rising groundwater the cause of dryland salinity?
One
Definitely YES as salt movement occurs as a solution in water.
Two
Definitely NO. Many systems susceptible to dryland salinity do not have watertables. An unreported CSIRO salinity study by senior scientists with ‘reputations’ in salinity involved the installation of piezometers in a system where the closest groundwater was more than 300m down. The piezometers never contained water.
Three
The general model has rising groundwater bringing sub-surface salt stores to the surface through upward movement of water. A simple analysis can demonstrate that while the groundwater level rises the net vertical movement of water is downwards. Salt cannot move upwards against the flow, hence the increase in height of the water table CANNOT bring salt to the surface.
The model applied to dryland salinity by those that understand hydrology assumes a confined aquifer whereby pressure from water percolating into the hills forces water vertically upwards on the plains. This model can be applicable but is by no means general. Moreover, it application has been simplistic in neglecting percolation of water on the slopes and plains.
The simple answer is NO, except in specific circumstances.
Four
Dryland salinity is caused by changes to the soil health (eg. loss of soil carbon, microbes and soil structure) and vegetation cover (eg. loss of perennial native grasses). The effect of these changes remote from the point of impact can be mediated through groundwater flows. Groundwater is associated, as it is the means by which changes are mediated, but is not causal. Groundwater is a carrier that affects outcomes, but it does not drive the process.
Solutions for WA
Firstly, WA scientists need to adopt an open mind and study the other intelligence on salinity offered by industry and community scientists. They need to let go of their egos and salinity belief systems, and step down from the pedestals. It would also help by reinventing WA Dept of Ag that lost the plot on salinity in the 1950’s.
Secondly, governments need to map the soil salinity pathways as potential targets for remediation. Public scientists and bureaucrats will need to look to industry expertise to do this.
Thirdly, scientists need to closely examine the relationship between current agricultural practices, soil health and salinity.
Fourthly, farmers need to adopt practices that build soil health and increases soil carbon, microbes and structure through no-till, restoring native perennial pastures and growing crops into these pastures, etc. The limited use of inorganic fertilisers and insecticides/pesticides will go a long way to helping to rebuild soil fauna and plant nutrition. Fortunately, many farmers in Australia have already started this process (see http://www.amazingcarbon.com for evidence) and are pioneering a new and positive approach to sustainable agriculture that must have a huge potential market in Asia in the coming decades.
This is the primary way that WA will save its soil and agricultural base. However, it must be farmer and industry driven.
Jennifer
Yes, I do sound like those who criticise global warming sceptics. It’s what happens when you are concerned about a problem that you perceive to be real and other people deny the problem exists.
Is the salinity debate analogous to the global warming debate?
I don’t understand the global warming issue well and there is a lot of conflicting information. My observation is that GW is only predicted, though there are some signs that the models’ predictions are coming to pass. Another unknown is whether the apparent or predicted changes are human induced or part of natural long term cycles – should we be trying to control something which is indifferent to our presence?
Salinity in my experience is real. It is not a prediction, it is an observed phenomenon, so it is not the same debate as GW. Water table rise can be caused and reversed by clearing perennial vegetation and then replacing it. Logging forests can cause a temporary water table response and then the regrowth forest suppresses the water table again, often to a level below that which existed before logging. There have been paired forested catchments that have been studied before treatment, and then one catchment cleared and the other retained as a control. The watertable in the cleared catchment rises, streamflow increases and stored soil salt is mobilised into the stream, and the control catchment does not change. This experiment has been repeated, to my knowledge more than once in WA and also in Victoria. Decades ago.
WA provides the starkest examples because it is only up to 50-60 metres of soil over a huge slab of granite. Due to generally moderate relief, and the tilting of this granite slab, and hence disruption of the old rivers, much of the wheatbelt does not have a natural drainage outlet to the coast. The ancient river valleys have been refilled with sediment and the landscape has not changed significantly on the surface for 10’s of millions of years.
Cleared farmland in WA typically sees a water table response, and by typically I mean in every case to my knowledge, but I am sure there will be an exception out there somewhere. If a cleared farm catchment is fully reforested, the water table falls again. It is possible to lower the water table with less than full reforestation, but that required proportion of reforestation is a hotly debated topic. One of WA’s south coast catchments, I believe the Kent, has seen a rising water table reversed due to the widespread planting of bluegum plantations.
If you travel along the eastern edge of the forest in WA, which is the western edge of the wheatbelt, you can see water tables coming to the surface within less than 100 metres of the forest edge. Under the forest, if there is a water table, it will be more than 10m below the surface. If you have cleared land upstream from an area of forest, the watertables typically rise in the forested valley due to the cleared land higher in the catchment.
In high rainfall (>about 900mm) areas, there has always been an excess of water in the soil profile, so the incoming salt has not accumulated significantly. Clearing these catchments only increases streamflow but without salt mobilisation. The same would apply in many places east of the Great Divide.
Deep water tables in the wheatbelt have been observed to respond quickly (a few days) to single large rainfall events. This suggests there is significant vertical movement of water down through the profile via old tree root channels. One anecdote from a farmer who pumps his groundwater to protect his house and sheds – a jump of a metre in the water table following a cyclonic storm in summer. The soil profile fills up from the bottom in many situations.
Water tables are rising over the long term and in general. The occasional drop in response to a run of dry years is soon overrun by a thunderstorm or a wet winter like this one.
I could go on, but I think the model based upon filling of the soil profile with excess water is well established. There are of course many local variations, there are perched seasonal water tables, subsurface lateral flows and tightly confined aquifers. There are many examples of those confined aquifers bursting through to higher levels or even the to the surface without the insertion of piezometers.
The MDB is not all the same as WA, and I expect the MDB contains every imaginable variation, including sediments hundreds of metres deep. Maybe some/many of these sediments will never fill to the point where vegetation is affected. None of us know how it will pan out, but it appears the response time will be very long. Which means if it happens, it will be very slow to recover, if that is possible.
What do we need in WA? Money obviously, you expected that. It’s a very complex problem even in our comparatively simple landscape and though the basic process is well understood, the details are lacking and that makes it difficult to respond effectively with appropriate treatments. Revegetation is going to be part of the solution, but there will always be significant amounts of water that is not transpired and will end up in the deep water tables. Drainage and pumping are also being applied; there are several towns that are being protected by deep pumping.
The most destructive thing is politics. When money is so tight, there are always fights over the resources and that includes trying to destructively discredit other workers. Even though all the individuals probably recognise that everyone has a part to play. National politics, such as people in some other corner of the country who don’t have problem (yet?), who for some reason want to tell us that we’re imagining our predicament, can be the worst. Canberra wants to keep our dollars, as per normal, and so anyone who argues that there isn’t a problem (meaning “in my neck of the woods”) gives Canberra the opportunity to do less and play one interest group off against another.
Canberra is also deliberately driving wedges between State Govt agencies and the farmers by building a fourth layer of government, known as Regional Catchment Committees funded directly by the Feds. Interestingly, these RCCs are now turning to state agencies to conduct research for the RCCs. The useless waste of resources due to our federal-state relations is appalling. We deserve to fail as a nation because of it.
Rog and Louis, catch some rainwater and boil it away. There will be a trace of salt left. In WA, salt fall has been measured at about 70kg/ha/yr near the coast, and about 20kg/ha/yr a few hundred kms inland. In a 400mm rainfall zone, 4 million kg of rain falls on each hectare and contains 20kg of salt. Only 5 parts per million, so naturally you can’t taste it. Stand on the beach near sunset or sunrise with an onshore wind blowing. The faint haze that you see blowing inland is a demonstration of the mechanism.
Rob, I’m happy for you, but you’re not convincing to me. Farmers in WA started filling in their Harry Whittington “Wisalt” banks years ago. If it’s all about soil structure, why do we see the same response in forested catchments that were felled by hand in the good old days? Why does the water table fall again if the forest is left to recover? Soil structure is a major problem and potentially more important economically than salinity. But that is a different topic. However valid and important it is, it doesn’t explain much about salinity most of the time. Farmer and industry driven – yes yes & yes. the sooner we get it away from the politicians, the sooner something will be achieved. Govt should help develop economic solutions to the problem and then return to the house on the hill where they do less harm. (And I’m a public servant.)
All this is in general, the broad overview. There are exceptions, unique circumstances – maybe salinity without a water table is a problem in some areas. But for most of the southern Australian wheatbelt, the filling bucket model still stands, in my opinion.
You are right Rick, there are salts in rainwater.
http://www.publish.csiro.au/paper/SR9760319.htm
Ricks,
My reference to ‘believer’ and ‘climate change’ was perhaps too ambiguous. No one denies ‘climate change’ – but the ‘believers’ confuse it with ‘global warming’ which is contentious.
No one denies that salt is a problem (not even the Ringer) – but let us discuss the detail and potential causes openly.
And to this end I appreciate your long comment.
So Jen – on what basis (evidence) do you believe in “climate change”.
Tim Flannery also says that *science is about hypotheses, not truths, and no one can absolutely know the future.*
http://www.smh.com.au/news/world/civilisations-darkest-hour/2005/09/23/1126982230888.html
Phil,
science has nothing to do with belief – it is the data
Louis – indeed !