Agricultural water demand management: is the glass 20% full or 80% empty?

This piece nicely summarises the situation faced by many countries, and the inadequacy of the "solutions" that have dominated investment since the time when aquifer overdraft became affordable, with the availability of cheap submersible pumps in the 1970s.

Wada et al (Wada Y, van Beek L P H and Bierkens M F P 2012 Nonsustainable groundwater sustaining irrigation: a global assessment Water Resour. Res. 48 W00L06) estimate that 18% of irrigation water consumption (I use that word with care) is supported by aquifer depletion. Hence the title ob my contribution.

So the problem is to take water away from existing users who have built livelihoods and businesses and careers on unsustainable water consumption. Politically, this is toxic--and readers of Richard Beasley's account of how this is going in Australia, reviewed elsewhere on this website, may despair that even a country that can afford to manage its resources properly is failing so miserably.

Water is the tragedy of the commons write large. That issue is most successfully addressed by quantifying the asset and assigning rights to its use--rights defined carefully on the basis of actual water, not "invented water", as François correctly concludes. Absent those foundations, donors must refuse to fund, politicians must refuse to subsidise, and academics must report the truth.

Chris Perry

I agree in general that modernisation cannot solve a problem and the need to use water balances at basin/aquifer level as a tool to control overabstraction. Situation of world aquifers is serious.
Besides modernisation, (just to enlarge the debate), the last trending topic is 'wastewater reuse' and poliy makers does not undrestand the hydrological cycle when making nice numbers of 'new resources' whe using UWWTP (many of them were already commited if they consider the cycle).. so the problem is nbot the technology nor the farmers nor the agronomist... is to understand the water cycle, the basin...

Governance, and sound policy.

It's always a bit difficult to adequately address a complex issue within a few paragraphs. But here are a few points:
1. There is no question about the overdrafting of groundwater basins.
2 There remains tremendous confusion between local (e.g., on-farm) irrigation efficiency versus basin irrigation efficiency. We were talking about that decades ago (Allen, R.G., C.M. Burt, A.J. Clemmens, and L.S. Willardson. June 1996. Water Conservation Definitions from a Hydrologic Viewpoint. Proceedings of the ASCE North American Water and Environment Congress '96. Held in Anaheim, CA. (CD-ROM) and (Burt, C.M., A.J. Clemmens, T.S. Strelkoff, K. Solomon, R.D. Bliesner, L.A. Hardy, T.A. Howell and D.E. Eisenhauer. 1997. Irrigation Performance Measures - Efficiency and Uniformity. Journal of Irrigation and Drainage Engineering. ASCE 123(6):423-442. doi:10.1061/(ASCE)0733-9437(1997)123:6(423)).
3. There are many unrealistic "solutions" such as irrigating only during the night. That is very complex because it incorrectly assumes a huge evaporative loss with sprinklers (please see http://www.itrc.org/reports/evaporationca.htm), does not recognize that for large-scale agriculture it would require twice the pump, pipe, filter, etc. size (as compared to 24 hours), and does not recognize the fact that for most canal systems we cannot just switch on/off. Many of the numbers regarding sprinkler evaporation were developed with single sprinkler evaporation, which does not represent the physical systems that are used. With Center Pivot sprinklers, with more modern sprinkler packages (widely used for 20 years now), the primary cause of non-beneficial evaporation is very fast rotation of the pivots around the field.
4. The perceived reduction in evaporation and transpiration with drip/micro is an error. Just look at the photo at the beginning of this blog. A careful look will show that there is a pattern of water running down the furrows. It appears that the soil surface in the furrows is wet, plus there is tremendous vegetation in the furrows. But beyond those simplistic observations, the facts are (at least in the western US) that a well designed and operated drip/micro system provides a better distribution uniformity (DU) and better control of the depths of water application. Yields/acre are tremendously higher for some crops, and about the same for others. BUT...the devil is in the details. Because of better DU and better control of depths, the plant growth throughout the field is much more uniform, there are no bare spots, and there is no stress (unless intended). All of these factors absolutely result in a higher ET/acre. This is not a mind-boggling concept. If there are more, healthy plants without stress......mmmm.....there is less ET??????? The confusion, of course, is when one compares the volume applied before and after to a FIELD.
5. And then there is the need to leach salts that accumulate at the fringes of the wetted patterns with drip. Minor detail, since the Leaching Requirement equations and principles don't apply for anything but vertical flow. This is a Reclamation Leaching problem, which requires additional water applications (not ET, but applications).....except that the soil surface needs to be wet, which temporarily increases ET.

But where I disagree with the discussion is at the level of IRRIGATION MODERNIZATION. I started out as an agronomist, and gradually evolved to on-farm irrigation. What brought me into irrigation modernization was the very simple realization that on-farm irrigation could not be properly managed with inflexible water deliveries to the farm. When we look around the world, the water delivery service to fields is horrible - typically some type of undependable rotation delivery. So just forget any concepts of good on-farm management, soil moisture sensors, applying water based on ET, deficit irrigation, and on and on. Those are all theoretical if the water is not controllable by the end user. But it's more than that - good water delivery control is absolutely essential if we need to manage return flows and groundwater. In California this has gone way past the theoretical stage in many areas. I'm heavily involved with a number of our irrigation districts that are effectively dealing with this extremely complex matter of salinity, groundwater levels, quality and quantity of return flows to rivers, changing cropping patterns, climate change, conversion to better on-farm irrigation methods, and so on. For sure, I can guarantee everyone that it's a huge jump from forums and conferences to getting the job done......and the only way you can seriously deal with these complex, inter-related issues is to have good control of the water movement throughout an area (e.g., irrigation district) on a real-time basis (not just looking at monthly theoretical allocations). This is the essence of irrigation modernization. The vast majority of irrigation modernization in the western US is definitely focused on canals, by the way. Certainly we use a lot of pipelines also, but once you get up to 35 CFS (cusecs), or about 1 CMS, the cost of pipes is huge.
6. The theoretical benefits of deficit irrigation is, in my opinion, incorrectly exaggerated. First, the concept assumes that irrigation water is actually manageable. I just stated that it rarely is. Second, if one looks at the actual Distribution Uniformities (DU) of water throughout a field, one realizes that the problem is not deficit irrigation (or lack of it) - the DU is so bad that finely tuned concepts such as deficit irrigation by 5% or 10% are completely theoretical and worthless. Third, once there is actually good control of irrigation water and a good DU, I really don't know any sane farmer that deliberately practices deficit irrigation to save water. Rather, it is a standard practice on many crops to maximize yield or quality of yield. Processing tomatoes need to be stressed before harvest to increase the % solids. Cotton needs to be stressed (both chemically and with water deficit) at key stages to prevent excess vegetative growth. Wine grapes need selective stress to produce high quality, and to minimize berry damage. Other crops, such as stone fruit (e.g., peaches and nectarines) need the opposite - they need very readily available water during fruit filling. But almonds need to be stressed before harvest to prevent disease and to eliminate damage to the bark during harvest. On other hand, almonds cannot be stressed too much or they have stick-tights (nuts that aren't harvested) which then attract navel orange-worms. And the list goes on. Bottom line: There is a huge difference between experiments in the lab on deficit irrigation, versus what farmers need to do.
7. Finally, is there any hope? Yes - I'm very optimistic. But many more people will first suffer because of the numerous points of confusion, before things are solved. Just look at the Murray-Darling basin, groundwater overdraft everywhere, etc. It will get worse before it gets better. Meanwhile, here's why I am optimistic:
a. First, there may be a movement away from red meat. I'm love red meat, but it appears to be a growing trend. We all know how much ET is required to provide a kg of red meat versus a kg of other foods.
b. But this is where I disagree with the pessimists - they look at FAO publications and say there there is a linear relationship (or similar) between ET and yield. So yield cannot be increased without increasing ET. WRONG. VERY WRONG. That research just says that if you decrease ET by 80%, you get an 80% decrease in yield (for a classic vegetative crop such as alfalfa). And the big thing that is missing is that those relationships only dealt with experiments that varied ONE variable - ET. The facts are these:
i. In California, I've seen average tomato yields move from about 35 tons/acre to about 70 tons/acre - with the same ET. Why? numerous agronomic reasons that I don't have time to discuss.
ii. Almonds - when I started, a good yield was about 1200 lb/acre. Now 4000 lb/acre is common. This has come with about 15% increase in ET. But the Y/ET factor is very favorable.
iii. Peppers - the same thing as tomatoes.
and so on.
iv. Corn yields? They have gone way up, but the ET is about the same per acre?

Why? - better varieties, better nutrition, better germination/emergence, closer plant spacings, etc. etc.

So I do NOT think that yield/ET is static. That is completely contrary to what I have seen over the years.

Regards

Francois - Yes, I'm quite familiar with the Egyptian story, and have seen your work on the subject. The plan is to "save water" to expand irrigated acreage. And, of course, the water balances do not consider the groundwater overdraft. It's the same story over and over again, and maybe this blog will help a tiny bit in that regard.

Regarding the question of "can you save water by increasing ET?" Obviously that appears to be a ridiculous proposition at first glance. The answer is: It all depends.

First, I think we all agree that "water consumption" should include 3 things: (1) ET, (2) loss of water to saline bodies or (3) loss of water to locations from which it is unretrievable.

Then there is the question of production per unit of ET.

So I'll ramble a bit:
1. Let's assume that the goal is to produce 1000 kg of some crop. If you can have proper timing of irrigation to avoid stress when needed, but stress when needed, and you also use the proper crop varieties, seedbed preparation, disease control, and fertility mix (it's not just water), then it is entirely possible to harvest 1000 kg with less ET.
BUT...there was likely more ET/ha (not per unit of production), but maybe in the 10-15% range.
So, if we start to think about this as a demand for so many units of production, and we can see that less acres need to be irrigated. If you buy into that argument, you can indeed "save water".

That is exactly where we are headed in California, I think. It's not a deliberate policy of the state or federal government, that's for sure. But we need to fallow about 1 million acres in the San Joaquin Valley in the next 5 years or so because of groundwater overdraft. Each groundwater basin has its own local management plan, but ITRC is working with several to develop the concept of allocating water by ET, not by acre. The focus will gradually shift to production per unit of ET, rather than production per acre.

On the loss of water to saline bodies - this is not a minor issue. Currently we don't have the desalination facilities to adequately treat agricultural drainage water. In California there have been many attempts, but only a few successes. Everything depends upon the salinity of the original irrigation water, and the crop salinity tolerances. But as we move to more high-value crops, those crops tend to be more salt-sensitive. There are a few exceptions such as pistachios in the US. There becomes a point where any deep percolation (regardless of the leaching fraction) is unusable because it would require so much fresh water to dilute.
What this means is that yes, higher on-farm irrigation efficiencies create a more saline leachate (deep percolation). But if any deep percolation is lost because it enters a "salt sink" (not as salty as the ocean, but still not re-usable), if you can minimize that deep percolation it represents a true water savings for agriculture, at least.

Deep percolation with traditional irrigation techniques can be considerable. Let's say (grab any number) it's 50% of the applied water (let's say applied = 1 meter). That 50% is degraded when it deep percolates. Now let's say that you have a good irrigation system and good management and the deep percolation drops to 13%, and ET increases by 15%
Original applied = 1 meter
Original ET = 50% x 1 meter = 500 mm

New ET = 500 mm x 1.15 = 575 mm
New gross applied = 575 mm/(1-.13) = 661 mm

Water available for other fields = 1000 mm - 661 mm = 339 mm

You can arrange the numbers any way you want, but the point is that with degrading groundwater quality we are starting to really focus on keeping as much water on top of the ground (or within the root zone) as possible.

There are also huge issues here regarding in-stream flows. Those aren't even considered in Egypt and other countries. We have serious regulations regarding qualities and quantities of in-stream flows. So efficient first-time use is important in reducing diversions, to maintain in-stream flows. No water savings - just a variation in where the water shows up.

Along with this, there are also many locations in the western US in which the parent material of the irrigated soils has nasty stuff like boron, general salts, and selenium. Any deep percolation from fields will leach this salt out so that return drainage flows have a much higher salt load than what would be computed by just considering the concentration from ET. And the types of salt such as boron and selenium have serious negative environmental consequences. So improving first-time irrigation efficiency is no longer a simple case of just looking at a water balance. It must combine that very true issue with the salinity (water quality) aspects. I could go on and on about the selenium and boron issues in return flows, but I just want to emphasize that those do not originate in the irrigation water. We have numerous examples of successful programs of improving on-farm irrigation efficiency to mitigate these problems - such as the Exchange Contractors in the San Joaquin Valley, and the Grand Valley and Uncompaghre Valley in Colorado. In all these cases, the parent material is old marine layers.

These are truly cases where the ET can be increased while simultaneously reducing total "consumption" if one considers the water quality aspect.

So it all ends up together in that excellent water control at all levels (canals, pipelines, on-farm) is necessary to deal with these complex, interwoven issues.

Dear François. Very interesting article and comments.

Complementary points that came to my mind after reading.
1- In numerous places, and in particular in southern Europe, the perspective of the Climate change already affecting our agriculture will see a switch from traditionally rainfed crops to supplemental irrigation and then with time continuous irrigation. This is currently happening in France where for example a large part of Vineyards now require access to water. So, all this means Increase of ET, Variability and diminution of Precipitation and very often Increase of Irrigation. In this situation, several choices can be operated: let the agriculture economy die (unlikely), adapt and be resilient (semantically popular) with water related and non-water related options as mentioned in the article. But the economic, cultural and political pressure will always push to provide access to water to this agriculture. Of course this will be done with the “more crop per drop” mantra and in the framework of the latest WDM techniques. But this will affect the part of the 20% full of your glass in numerous parts of the world in the next decades.
2- Developments are ongoing to tackle crop water stress and ET from Remote sensing using thermal infra-red sensors. This is only available at large scale with MODIS and Landsat satellites but will come to a 60m scale with the Trishna satellite in 2023. This does not limit ET, but it might lead to adjust the estimation of the water needs and increase again the water use efficiency. These applications will be available to only a few, but with time this technology could be made available to more and more. Coupled to Big Data AI this is one of the next instruments of the WDM toolkit.

But as you say, all this will not invent new water. Shall the major water savings be looked into the Food Chain efficiency?

I appreciate very much, Charles' and Francois' very well worded and written descriptions. I agree with nearly everything stated. Well said. As described by Lecollinet, the impetus is on us technical ET developers to get all of the remote sensing of ET ducks lined up and made dependable and available. Some of this is happening through the OpenET project in the USA, with other efforts around the globe. For example, tomorrow morning is the inauguration webiner in a series on remote sensing of ET (RSET) in North Africa and the Middle East, developed by Pasquale Steduto and hosted by FAO. The webinar will describe a number of operational RSET models with east Mediterranean applications. OpenET will be described during a later webinar in the series.
The web site for registering and reviewing the program is at:
https://urldefense.com/v3/__http://www.fao.org/index.php?id=110705__;!!JYXjzlvb!zAUlx5rZi_Pep4zLvN-TcCPOzSaFgdG7IXblznlrFDuLLOAW8ZIjMKZ2pocgJms$

If this link does not work, you can probably google it. Unfortunately, the time is 1 pm Cairo time, which, by my calculations, is 4 am Pacific time (sorry Charles (!!)).

Francois, I hope that the contributions above, and those that follow, can be captured into a publication in some way, perhaps in Nature or Science, etc. to reach up into some of the higher policy setting levels. As we know, impacts of "water saving programs" rank right up there with impacts of climate change, both in regard to injury to global populations and in regard to stranger-than-life misunderstandings.

Rick Allen, University of Idaho

Dear François (congrats on your excellent piece) and dear all,

The case of l'Albufera de València (Spain) is really complex and is probably a good reflection of a transition, barely begun, in the paradigm of irrigation modernization. I'll try to sum it up, sacrificing quite a few details.

L'Albufera is a freshwater wetland (Ramsar site) dependent on the cultivation of rice and the irrigation surpluses of a large area dedicated to the cultivation of fruits, irrigated mainly by the Acequia Real.
The Acequia Real began a modernization process financed by the government at the beginning of the 20th century, whose main objective was the liberation of flows to meet other water demands of the basin and the transfer of resources to the neighbouring Vinalopó basin. This was stipulated in the official planning documents of 1998. So far, the works have transformed 40% of the irrigable area of this canal, but only a small part is connected to l'Albufera, since half of the irrigable area returns the irrigation surpluses on the river Júcar. Consequently, during the first two decades of the century, it has been possible to cause a moderated decrease in the surface and underground contributions of the wetland.

The Basin Authority has estimated that until 2015, the modernization works have generated a "saving" of 60 Mm3, of which it can be assumed that a small part has been obtained at the expense of the Albufera inputs and another, larger, on return flows that are returned to the river. This institution also argues that these 60 Mm3 have been used to cover the global deficit of the basin and that they have been used by other users, among which are now also the irrigators of the Vinalopó.

However, since 2015 there has been a change in management criteria. The Basin Authority, pressured by environmental NGOs and by scientific evidence of the rebound effect, has shifted this policy. The 2015 Basin Water Plan obliges to withdraw from the water rights of the Acequia Real the savings generated by any modernization action, and this same volume of water must be directly introduced into l'Albufera. The new planning cycle (2022-2027), whose preliminary documents have already passed the allegations phase, contemplates a forecast of savings of 38 Mm3, which as they are generated, will be withdrawn from the water rights of the Acequia Real and sent to l'Albufera. In fact, this winter 12 Mm3 have been sent, in coordination with local environmental administrations.

In short, it seems that little by little, and still in a pioneering way, formulas are being opened that leave behind the empty part of the glass and are oriented towards the full part of the glass. It is early to know, in this case, if it is 20-80% or 50-50%!

Investments in irrigation efficiency have political ramifications that extend beyond their technical features and may explain their preeminence in water management discourses. I would like to offer the example of the 50 000 hectares Crau Plain in Southeast France, which is irrigated via several centuries-old irrigation canals sourcing water from the Durance River (and may present some similarities with the Albufera case). Farmers have developed agro-pastoralist systems for centuries with irrigated grasslands (15 000 ha) and about 80 000 sheep. The semi-arid steppe ('Dry Crau', or non-irrigated grasslands) is a protected 'natural area' where flora and fauna species depend on sheep grazing.

Crops consume about 20% of irrigation water, whereas return flows make up 70% of the recharge of the Crau aquifer (with a total volume of ~550 Mm3; Symcrau, 2020). The latter 1) serves as a drinking water reservoir for 270 000 people, 2) is intimately connected to multiple local wetlands (one of them is a national protected area and Ramsar site), and 3) contributes to keeping saline intrusion at bay.

Despite those well-studied environmental and socio-economic benefits, Water Users Associations that need public subsidies from the Water Agency (alongside with European and regional funds) to keep up their open canals are asked to achieve substantial water savings and increase efficiency. Indeed, following its environmental objectives, the Water Agency can only subsidize interventions if they generate water savings, in this case benefitting the Durance River basin aquatic ecosystems. Such conditions might jeopardize –if water savings are not forthcoming– WUAs' access to subsidies and their capacity to maintain Crau's ancient canals, and thus the complex social and ecological system that depends on them.

As shown in the case of drip irrigation (Venot et al., 2017), water-saving policies are not neutral, but instead anchored in specific cognitive frameworks and cultural backgrounds, as well as political struggles over water access, and vary greatly between different contexts. This may explain the fixation on a narrow idea of 'efficiency' that displaces a broader ecological viewpoint.

In our example, irrigation modernization for environmental purposes rests on a 'modern rational' where society and nature have been considered as two different realms in policy interventions. Ecological benefits of return flows are disregarded because there are not 'natural', and gravity-fed canals belong to the engineering realm, where interventions are based on calculation, optimization and modernization. Marshes that are 'artificially' alimented by the Crau aquifer are not valued as much as 'natural water bodies' for which specific management objectives have been set according to European regulations (2000 Water Framework Directive).

It would be of great value to analyze modernization irrigation projects under those multiples facets, to better understand how and why such technologies are proposed and pushed for (if not imposed), even where they seem flatly inappropriate when water resources are considered through their multiple pathways, uses and functions.

Symcrau (2020). Etude Sinergi. Sensibilité de la nappe aux conditions de prélèvement et de recharge. 168 pages.
Venot, J., Kuper, M., & Zwarteveen, M. (2017). Drip Irrigation for Agriculture: Untold Stories of Efficiency, Innovation and Development. Routledge.

Overall, for those familiar with the concepts of the hydrological cycle and closed river basins, it is not that hard to grasp the falsification of optimistic justifications usually associated with WDM projects to save water. But what is the problem with the governments that are willing to cover this vivid truth? Don't they understand what they are doing?! Maybe they didn't have an idea a few years ago, but I think for sure they do now. I have witnessed many times in my country, Iran, that several well-respected hydrologists gathered acknowledging the truth behind the typical WDM-labeled projects to policymakers, based on their own national experiences and the facts revealed in a few international reports. But still, significant investments for the sake of agricultural water management are going into projects like lining canals, replacing canals with pipes, modernization of irrigation systems, and so on. I don't want to say the situation now is the same as before when these projects had no critics. Yes, there are now some voices calling for change. But the show must go on!

The fact is that while the false promises of typical WDM projects sound like an insult to our understandings and identity, for the network of power constellated around these usually expensive projects, this is only a word that helps them to present and pack their plans better. It took a long time for this network to shape; now, we cannot expect to break it with some truth-seeking scientific reports or articles. This network contains a large scattered number of folks from top to down who don't (sometimes can't) bother themselves listening to our challenging claims. High-profile politicians, technicians, consulting firms, a considerable number of academicians, and more importantly, a vast number of helpless water users seeking a solution to come up with the ongoing water scarcity are all among this network.

The most important thing that we all have to worry about is the false promise of WDM (vast potentials of water-saving) which is "stealing our thunders." Our thunders are all about changing the development path and looking for innovative, socially-driven solutions instead of technical magics. As Francois and several contributors emphasized, WDM projects have significant agronomic impacts; but the main problem is that the discourse built upon WDM-labeled projects is stealing our thunders. Unfortunately, the powerful discourse of saving water through WDM projects has hijacked barely appearing initiatives for rethinking water management and development. It somehow works as the water supply options/solutions that can ruin the efforts targeted for sustainable societal change. A real change will be time-consuming and full of conflicts, but the painless promise of WDM is charming and unavoidable for water users and politicians.

An example of a hijacked initiative in Iran is Lake Urmia Restoration Program. The lake (an endemic hyper-saline Ramsar wetland) has witnessed continuous shrinkage in the last two decades due to the over-developed agricultural sector. Seven years ago, after a lengthy debate over the solutions and causes, the political will for restoring the lake made possible the initiation of a national program to restore the lake. For the first time, the president and his cabinet had accepted the role of over-development in the shrinkage of the lake. But the flow of water management finally trapped into a narrow-minded approach with technical projects including dredging the rivers, flushing the dams during winter to the lake, diverting the treated wastewater of large cities directly to the lake, modernization of irrigation systems, and so on. It could have been appropriated as an opportunity for rethinking water management, but unfortunately, it finally rendered into a simplistic plan for adding water to the lake without abating the crisis's roots. The idea that we can save water from the agricultural sector for our more precious/vital demands with the implementation of a few technical projects (without harming the agricultural sector) is very charming for politicians. And this is exactly what now the managers of this program pump into the public media!

Dear Francois,

Thank you.

Mostly dichotomies promote flaws. Supply side or demand side? Consumptive water or non-consumptive? Technology or traditional? … I say both to all such questions.

On the other hand, the conceptual frameworks are wrong. For example, for decades we know that the Classical Efficiency (CE) and Water Productivity (WP) are erroneous. Yet, in 2021, US, Europe, China, India… all use these two indicators in their water policies and designs. So, most of the WDM (if not all) produce flawed policies because of being based on at least one of these two erroneous concepts. It is rather perplexing that experts give all sorts of names and symbols to these two concepts to get away from it.

Having said these, among others, you write that "demand management appears as a … cheaper and greener option". Having in mind that WDM must be based on a learning approach, I would like to suggest, as Peter Loucks and others do, that it is mostly more expensive. This becomes doubly true if management becomes comprehensive.

Regards,
Naim
https://sites.google.com/view/naimhaie5

Thanks for raising this interesting and vexing issue.
Like so many others in this discussion, I have also spent a lifetime trying to get policy makers and heads of ministries see the simple (childs play) arithmetic of a mass balance.....what goes in equals what comes out, plus or minus storage. So, when there ain't no more water (for extending canals, irrigation command areas) - there ain't no more water. Creating it out of some magic based simulation routine with lots of fancy bits and bobs, stuck in as variables gives the result "42" - being the answer that Deep Thought provided after 7.5 millions years of contemplation (with apologies to Hitch-Hikers).
What my experience has told me that there is financial corruption in bucketful's (in extending channels, extending command areas, etc) - which is plain to understand (though not accept). Worse, and much worse, its accompanied by intellectual corruption too. Some of the latter comes packed under the guise of high ranking academia 'thoughts' sitting in ivory towers. As many have said above - 'tis time to point out the emperor with no clothes on. Mind, time is short, though.

The irrigation modernization process in Spain is a textbook example of the various paradoxes associated with irrigation technification, described in (Perry & Steduto, P. 2017) (Grafton et al., 2018) and other recent documents already mentioned in the opening post raised by Molle.

Some figures of this Spanish process:

Since the start of the intensive modernization process in 2000, more than 1.5 million ha have been modernized (about 50% of the initial irrigated area in 2020). Free surface water conveyance and water application systems on-plot have been replaced by pressurized water distribution networks and sprinkler and drip irrigation systems.

Public funding has been generous, in practice it represents between 75-65% of the costs of the collective pressurized distribution networks. In some cases, on-plot water application facilities have also been subsidized. The argument to justify these subsidies to the taxpayer has been to achieve “water savings thanks to increased efficiency”, in an environment of growing scarcity of resources. The total costs of modernization (collective network and facilities on the plot) are in the range of 8,000 -10,000 euros / ha

The survey carried out by the National Institute of Statistics INE (1) on the annual use of water as declared by the WUAs in the period 2000-2018, proudly exhibits a reduction in use from 16,900 hm3 to 15,500 hm3, - 8.3% (optimistically -12.6% considering a linear regression for the whole period). These hypothetical declines in the use of used water are widely publicized by stakeholders, WUA and policy makers, as a sign of the success of the investments dedicated to increasing “irrigation efficiency”. But when these results are aired to the public, they confuse the concept, intentionally or not, and refer to them not as "descrease of water use", but as a "decrease of water consumption" and "water saving".

In parallel, the irrigated surface, (surface that had remained relatively stable from 1990 to 2000,) has experienced constant growth in the period 2004-2018 from 3.3 Mha to 3.8 Mha (15% increase). A large part of this growth has occurred in the south of Spain, where the availability of water is lower.

The coincidence between the start of the modernization processes, and the growth of the irrigated surface (without the entry into service of new regulation dams), leaves little doubt : these increases in irrigated surface have been the destination of an important part of the volumes of water not used after modernization. Thus the modernization has bring the fuel that has allowed the increasing of irrigated surface, inducing the final increase in water consumption.

At the same time, production increases have been achieved as modernization makes possible suppress water stress, shift crops, intensify planting pattern and implement double annual harvest s. It is obvious that all this has increased the productivity of the water used in terms of kg useful biomass / m3 water used.

But the inherent questions still are there… has water consumption decreased over this 20-year period of large efforts? There have been a savings of water available for basin management, or not? Despite the academia and NGO have repeatedly demanded answers to this relevant questions, no data (neither systematic nor occasional) form agriculture or water authorities has been provided based on real measures of the returns decrease or on the variation in water consumption (ET ). This lack of interest in measuring and getting precise answers is by itself highly suspicious, being in mid that direct ET measures can be easily obtained from satellite observations available form long ago.

EU Common Agriculture Policy (CAP), that heavily funds these investments, does not control the water consume results, and only introduces testimonial requirements of effective 2.5 to 12.5% reduction on "water use”, not always, but only in some conditions with declared water scarcity on the basin, conditions that are easily cheated. The infamous article 46.4 about Investments in irrigation in the “Regulation No 1305/2013 on support for rural development by the European Agricultural Fund for Rural Development”, is a master piece of deliberately confuse redaction (4).

Only a few academic and NGO studies have directly measured the effects in specific cases through field studies and / or aerial / satellite observations from NDVI.

Two examples:

The case described in this forum in a previous comment by our colleague Carles Sanchís, meets all the conditions for the modernization to achieve favorable productive and environmental effects simultaneously: the behavior of 5 plots surface irrigated and 6 provided whit drip irrigation in the same irrigation district are compared throughout an irrigation season . It is concluded that with the technification, production has notably increased, while maintaining ET (in this case of traditional citrus cultivation with large tree spacing, the increase in T is offset by the decrease in E), and obviously reducing as well the use of water. In this study case, after the modernization, the crops and planting pattern were maintained, the irrigated area did not increase, and the unused water is planed to be used entirely to improve the flows and water quality of the basin that flows into the Albufera estuary . The pressurization of the distribution network is realized by gravity, regardless of energy. This is a showcase case that indicates how to do things well. But this success story ... is it the exception or the rule?

In (Jiménez-Aguirre &. Isidoro, 2018) (2) another case is described in detail: a large system of 4,000 ha has been studied over 20 years, with numerous data before and after modernization. Surface irrigation has been transform in to sprinkler irrigation. Pressurization is achieved through pumping stations, with significant energy costs. After modernization, previous crops (cereals, corn and alfalfa) remains, but they are intensified and double harvest are introduced. In this case, both E and T increase, and therefore the water consumed increases, although the reduction in returns is greater than the increase in consumption, and the water use still is reduced. However, the saved-not used water, which is not now being withdrawn for this WUA, is not destinated d to improve the environmental flow conditions or the quality of the Gállego river that feeds the system, but is still being withdrawn and destined towards other irrigation districts downstream the canal from which this WUA is fed. Conclusion: The basin has lost water returns, and water consumption has increased, both in the initial WUA and in the destination districts were such volumes will flow. Finally, although the exported masses of pollutants (nitrates, salts) are reduced, the water volume in returns flows are reduced even lower, making the concentration of pollutants, increases or remains as high as before the technification, which already exceeded the limits of the European directives . This case of marked rebound effects in quantity and quality… is the exception or the rule?

In my experience, the second type of case is the most frequent, being the first nearly exceptional. Whether they are sprinkler or drip systems is not very relevant in the bottom line. The absence of governance is much more important to contain the pressures of regional politicians and farmers' associations installed in the thought that the continuous expansion and intensification of irrigation to infinity, and beyond, is possible.

As this personal perception could be biased, there are a series of direct and direct indicators that give the clue (they are the smoking guns) to conclude that in the overall balance, although the use of water may has reduced as a result of modernization, water consumption has increased.

This observation, apart from delegitimizing the justification used to grant public funds, can have serious implications in a context of non-compliance with the commitments established by the Water Framework Directive 2000/60 / ec in the EU, and especially in the perspective of the enormous impact that the climate change is foreseen in Mediterranean coastal countries with large installed irrigated areas (see 2018 report from the Joint Research European Commission, ref 3) whose implications seriously threaten the survival of irrigation (and a large part of agriculture).

As my contribution at this point as been extended too much, I will leave these aspects to be developed perhaps in a second comment if they are of interest.
NOTE AND REF

(1) Survey based on statements from a WUA sample, not direct measurements from an independent entity. It does not include estimates of unauthorized uses, which WWF estimates at 3,400 hm3 / year mostly through illegal wells.

(2) (2018) JIMÉNEZ-AGUIRRE, M.; ISIDORO, D. :” Hydrosaline Balance in and Nitrogen Loads from an irrigation district before and after modernization” Agricultural Water Management 208 (2018) 163–175. https://doi.org/10.1016/j.agwat.2018.06.008

(3) (2018) BISSELINK B; BERNHARD J.;GELATI E.;ADAMOVIC M.;GUENTHER S.;MENTASCHI L.; DE ROO A.“Impact of a changing climate, land use, and water usage on Europe’s water resources: A model simulation study”. JRC Thecnical Report. European Commission
https://ec.europa.eu/jrc/en/publication/impact-changingclimate-land-use-and-water-usage-europe-s-water-resources-model-simulation-study.


(4) REGULATION (EU) No 1305/2013 OF THE EUROPEAN PARLIAMENT AND OF THE COUNCIL of 17 december 2013 on support for rural development by the European Agricultural Fund for Rural Development (EAFRD) and repealing Council Regulation (EC) No 1698/2005.
https://eur-lex.europa.eu/legal-content/EN/TXT/PDF/?uri=CELEX:32013R1305&from=ES

WDM of agricultural water is theoretically very attractive for reducing over-consumption of irrigated water. For example, in Euro-Med as well as in South and East Med countries agriculture consumes about 85% of total water withdrawals. However practically, WDM is not popular among politicians and farmers, mainly because, in contrast to WSM, it is more time-consuming, economically expansive, and asking for a change of human behavior.
Two years ago as secretary of state responsible for water resources management in Greece, I created in the ministry a special unit for WDM. To promote an “integrated environmental management”, the new government that came out after the last election has moved the management of water without a WDM, to a new department for forestry, water and biodiversity. This is to show how an “integrated systems approach” can mislead the meaning of the Integrated Water Resources Management (IWRM) paradigm.
WDM in agriculture could be efficient as part of the IWRM process. In Europe, the IWRM model has been used as the background of the EU-WFD 2000/60 policy regulation, emphasizing water quality, while including quantitative issues.
Unfortunately, its fitness check reported by the EU-Commission in 2019 has demonstrated its failure to include agriculture in a cross-sectoral integration. 20 years after its implementation, the EU-WFD has produced mixed results and I think it is now time for its revision.
In the meantime as an alternative, the Water-Food-Nexus application in agriculture can save water in parallel with the WDM. The idea is to examine only alternative solutions of food production and energy use that respect water security. For example, saving energy costs can recover possible loss of farmer’s revenue due to a decrease in irrigation water. For more details see:https://www.femise.org/wp-content/uploads/2021/03/FEMISE-MEDBRIEF-31-final.pdf

Thanks to Francois, Charles, Ricardo and others for their very pertinent comments.
Based on our work in India, China, the US and Brazil, I would like to add the following observations:
1) Improper crop choice relative to the climatology or rainfall is a significant contributor to groundwater use and depletion. Rice grown in semi-arid regions in India, and procured at a guaranteed price by the government, with "unlimited" electricity supplied for a fixed annual connection charge, is the poster child of this situation. However, crop choice shifts that emerged in the US after the subsidized crop insurance programs were introduced, and subsequently the requirements to include biofuels were added provide a similar example. Even in California and in the Western USA, the prior water rights doctrine, and the interest in feed for cattle promotes high water usage with low economic return. Our modeling of the Indian situation shows that aggregate net farm revenue in India could increase with dramatically reduced water usage and reversal of depletion in the key areas, if the government just shifted where they procure rice and wheat -- they would need to support those farmers by procuring traditional crops that were grown in those areas before the government programs changed the cropping pattern.
2) As noted by others, agronomic and irrigation practices can lead to significant yield increases, without a proportional ET increase -- reducing ET is feasible without impacting yield. Our experiments with farmers in Punjab, India demonstrated this quite effectively. However, getting farmers to maintain these practices in the absence of reforms in procurement and electricity pricing is not easy. The point that water saved will be used to simply increase irrigated area or intensity has been made by a lot of people. Ultimately, the costs and benefits for the farmer will have to see a tradeoff, and at the very least if the farmer starts realizing substantially higher productivity and income from the same amount of water, that is at least a strike for efficiency. Higher productivity in many areas comes with lower prices especially if the demand is locally limited due to transportation costs and duties. So, there are feedbacks that can signal a general equilibrium regionally -- it is not just about WDM, but managing the farm economics in a regionally balanced way.
3) Farmers are inherently risk averse, but they are also interested in innovation and in better economics, so WDM and policy levers attached to IWRM fall flat unless they approach the problem from an economic and farmer decision making perspective.
We have no shortage of people in the field who make significant policy statements on water and other areas. It is good to have these ideas discussed, but at some point we have to think about the "decades" over which these kind of statements have been made, and what steps can practically be implemented to effect improvements, as well as what we mean by short and long term improvements - from the perspective of the people who are actually using the water.
Several of the points made in previous posts are actually right on as to the practical difficulties in achieving WDM, and clearly hint at aspects of access and reliability that need to be addressed to even have a shot at making a change.

Thank you, Manu, for this comment: "The point that water saved will be used to simply increase irrigated area or intensity has been made by a lot of people." Yes it has! And I for one am growing quite weary of hearing it!

The failures in implementing water-saving programs due to expansion of acreage or increasing crop productivity are ubiquitous and these failures do need to be made continuously with policy-makers. Thank you to those of you that have tirelessly attempted to communicate this point to politicians and water managers. However, as a hydrological scientist I would very much like to see our internal debates focus more acutely on two simple questions: (1) is it possible to reduce consumptive water use -- and under what conditions -- while maintaining the same crop yield? and (2) is it possible to increase farm revenue while not increasing consumptive use?

I personally believe the answer to (1) is yes, and our 2017 paper was an earnest attempt to inventory credible field studies that met the criterion of controlling for increases in crop productivity or acreage. However, I am increasingly dubious that many of the technological and other agronomic advances required to save water at a meaningful scale using the strategies we summarized can be practically implemented, due to the immense political and administrative challenges that many of you have articulated here (the Murray-Darling being one of the most telling illustrations of these challenges).

I therefore think that (2) might be the more important question for us to address. Some farmers in the Lower Colorado River Basin in California and Arizona appear to have been able to reduce their consumptive water use while increasing their incomes through crop shifting. It would be great to learn of other cases. Farmers in other areas of the Colorado River Basin have been able to increase their income by accepting compensatory payments to fallow (see Richter and others 2020 in Nature Sustainability, supplementary information). I would like to see other carefully-scrutinized cases that examine the potential for improving farmer incomes while legitimately saving water (and reallocating it back to the environment).

At the end of the day, in so many basins around the world, regional economies and ecologies are going to be repeatedly or chronically devastated if we cannot provide clear instructions for reducing consumptive water use in farming. I continue to retain hope that we can do that.

Richter, B.D., D. Bartak, P. Caldwell, K.F. Davis, P. Debaere, A. Y. Hoekstra, T. Li, L. Marston, R. McManamay, M.M. Mekonnen, B. Ruddell, R.R. Rushforth, and T.J. Troy. 2019. Beef production is leading contributor to water scarcity and fish imperilment. Nature Sustainability, https://doi.org/10.1038/S41893-020-0483-Z

A consensus that is not enough.

Although the reflection that has opened the topic asks about the effectiveness of WDM measures in irrigation systems in basins where water scarcity is manifest, during the comments we have focused mainly on measures related to modernization. This is not surprising given that it is the most frequent and most visualized proposal in medium and large-scale state projects. It is a good example of the politically correct "tripod of measures" that public institutions like to promote in facing any problem (not only related to water use):

- Infrastructures building.
- Technology introduction / development.
- Adoption of good practices.

These types of measures are traditionally welcomed by producer and political agents, and are also liked by companies and researchers, since they put money on the table for everyone, and generate agreement that diverts (or postpones) social and economic conflict, avoiding adopting unpopular measures. They also feed back on the perception that any dysfunction can be overcome by means of some technology that does not require the change of long standing tendencies or redefine benefits.

However, when there is a high degree of water overexploitation, or quality degradation, this "standard action tripod" has proven insufficient (even when trying to avoid perverse rebound effects) to achieve palpable results.

The elephant in the room.

I believe that there has been a coincidence in all the interventions that modernizing irrigation alone is not a measure to save water consumption or improve water mases quality, if it is not accompanied in parallel and simultaneously by other measures rigorously applied, apart from avoiding the increase of irrigated surface.

For example, in the case of irrigated crops with large water needs destined to animal feed or biofuel production (1), modernization should simultaneously implement a program including :

a) The shifting of crops cultivated to other with higher added value and profitability (human consumption) per unit of ET (taking advantage of agronomic technology that supplies the most appropriate varieties and management).

b) The reduction of irrigated area, a least in the plots where the shift occurs.

c) The maintenance of a part of the herbaceous crops acting as a fuse for cases of persistent drought (compensated with insurance covering).

In this way it is possible to achieve reduced final water consumption, sustaining or increasing of the benefit of the farmers who adopt the change. The permanent (or perverse) subsidies that in many cases in EU support the economically deficient productions (1) of herbaceous under irrigation, can perfectly be redirected to finance the support for the transition on cultivated crops, which has important collateral and adaptation costs. The greatest difficulties to be found in many cases are not so much the climatological or edaphological limitations, but the inertia of the productive structure and the conditions of the market for the yield commercialization. In these types of situations the process is not trivial, but it is feasible, especially if the subsidies are redirected in the right direction. It can work even if modernization has already occurred (which will make it easier to undertake the crop shift).

However, in regions where modernization has already been carried out, the changes have materialized and the best agronomic and control technologies (2) are being applied,.. but in parallel there was an expansion of irrigated area that canceled the potential savings of water consumed,… the only solution that remains is to reduce irrigation surfaces, possibly spreading the impact between traditional and modernized sectors.

Therefore, in both extreme cases, the reduction of the irrigated area enters the equation, and yet it is the measure that is least formulated in the WDM alternatives, being certainly effective, althought traumatic ... It is the elephant in the WDM room.

This reduction in irrigated areas in stressed basins, places us in the opposite direction of the current of decades or centuries of expansion. It will inevitably happen in the territories where, as a consequence of the worsening of the Climate Change, a high Water Exploitation Index + (WEI+) (3) increases further more. In case this worsening continue, even if the situation becomes not as crude as the predictions announce, it is necessary to initiate a rational, gradual, negotiated and fair reconversion measures for the distribution of the social and economical burdens associated to closing irrigated surface . Otherwise we will witness a chaotic and destructive implosion where small/medium-scale irrigators will be ruined and expelled from their activity.




NOTES & REFERENCES

(1) Many of these irrigated crops would not survive without direct CAP subsidies

(2) I.e.: woody crops with water allocation as low as 1,500 to 2,500 m3 / ha per year can hardly reduce their water use with any technology or management in arid conditions .

(3) Water Exploitation Index + https://www.eea.europa.eu/data-and-maps/indicators/use-of-freshwater-resources-3/assessment-4

Thanks a lot Upmanu, Brian and Ricardo for the excellent points made. Before I turn to them, I am glad to see that Brian agrees with the limited scope for not-easily scalable plot-level solutions. As to the repeated efforts made to debunk 'bad good-ideas' it is certainly comforting that most hydrologists have understood the point but, as you're well aware, the story at the policy level is a different one. This certainly begs the question of what should be done to avoid the repetition of environmental devastation. I am not sure that merely turning to other issues will do the job.
You point to two other options. The first one is straightforward: temporary land fallowing programmes: in the North China Plain the Seasonal Land Fallowing Policy (SLFP) has fallowed 133,300 ha in 2019 (our forthcoming Water Alternatives issue will include a paper on that experience). Charles Burt referred to the fallowing of about 1 million acres in the San Joaquin Valley in the next 5 years (I am not sure this is planned or a proposal). We have seen other examples in the Imperial Valley District, in Spain and other countries. I do believe this will develop and is a solution in countries which can offer financial compensations. Ricardo's 'fuse' in the form of herbaceous crops is interesting (note that in many cases the opposite is incentivized: fruit trees, with a rigid water demand). The permanent version of this is the buyback of rights: a generally costly option which only makes sense if enforcement is strong and if we can make sure farmers will not shift to another resources (e.g. groundwater), or harvest/store more water on-farm, etc.
The second option is therefore to elicit drastic changes in cropping patterns through changes in incentive structures or procurement. For some odd reason crops with good economic returns tend to be quite thirsty (though pistachio indeed is an exception!) but in any case if such a crop (better return, less water) was available, farmers would probably have chosen it in the first place. If the market has water or energy implications that are deemed unacceptable (eg fodder crop grown in Arizona shipped to the Emirates) it needs to be redressed through incentives. This may take us beyond the topic of this post but, indeed (Ricardo), subsidies are often perverse rather than ameliorating, and as always such interventions have systemic affects that requires 'managing the farm economics in a regionally balanced way', as Upmanu emphasized.

The discussion certainly generates a lot of thoughtful comments and examples. Excellent--thanks to all!

We can agree on the fundamentals: in many areas, GW use is mining a resource that will become unusable. Option one is to control the mining so that GW remains as a limited "renewable", high productivity contribution to agriculture. Option two is to allow depletion so that GW is no longer locally available as a high productivity “buffer”. Those are the only two options—and option two will be much more damaging to local economies than option one.

Optimistic, feasible scenarios that will maintain production at lower levels of water consumption must address the primary challenge: how to transition to that nirvana without actually making things worse in the interim. Nirvana requires (a) control of consumption; (b) better technology for precise water control; (c) improved system management; (d) crops that generate more $/drop… and perhaps (e, f, g) better extension services, marketing facilities ant other supporting infrastructure.

Commonly, interventions focus on everything except (a), on the assumption that if some elements of (b)-(g) are in place farmers will magically demand less water. Wrong—they will want just as much, if not more, or the now-more-valuable input!

Alternatively, if we do (a), slowly and progressively, farmers, and the market, will figure out which elements of (b) onwards are desirable. And they will be good at it.

I recall some modelling work about California exploring how incomes would be affected by enforced reductions in water consumption. (If Alvar Escriva-Bou is reading, perhaps he will confirm/correct). A 12% reduction in water consumption led to a 6% fall in gross value of ag production and a 3% fall in farm incomes—and that was “current technology”, excluding the additional positive potential for all the innovations that such pressures would induce!

So I agree with the optimists (Brian Richter, Charles Burt, etc)—more with less is possible.

But I remain a pessimist: the politics of that route are beyond most democracies. From this perspective, Australia is a failed state. California will be fascinating.

A day or two ago I put up a link to my upcoming Zoom presentation in mid-May for IAIA 2021, which is the annual conf of the primary professional society for impact assessment consultants and enviro planners worldwide. The topic was perfectly germane to this thread, i.e., Thailand's plan to alleviate the worsening subsidence of metro Bangkok caused by groundwater overdraft, in the face of the dry season discharge of that country's heartland river, the Chaophraya, being essentially reduced to nearly zero, as a result of double- and triple-cropping rice upbasin above Ayuthaya. A significant reduction in export-oriented riziculture there is essentially unthinkable. The proposed remedy is an inter-basin transfer (IBT) scheme to divert ~300 cumecs from the Salween (or Thanlwin in Burmese) for the three driest months. This is a profoundly controversial issue bound up in ethnic minority politics inside Myanmar, including armed resistance, and is exacerbated by that the preferred solution to the enormous energy demand of the prospective IBT, which would most efficiently be met by constructing the first mainstem dam on the Salween/Thanlwin, which is SE Asian's. largest free-running river. Of course the military coup by the Tatmadaw on 1st February radically complicated the situation. Here again is that URL...

Apologies for being so late to the party with this contribution.

This has been an interesting discussion, and we are grateful for the opportunity to contribute based on the Australian experience.

If we can summarize a few of the relevant points mentioned in the posts above:
- Australia is failing miserably to achieve water savings despite billions of dollars in investment
- Any savings that are made will likely not flow to the environment as hoped
- Despite repeated demands for evidence, no government agency has ever supplied numbers in support of the program/policy choices
- Buyback is a generally costly option that, without enforcement, will simply see expansions in groundwater extraction
- Subsidies are perverse and we should be looking to a ‘farm economic management model based on regional balance objectives
- Rather than adaptation we are heading toward growing vulnerability in our systems

Let’s try to address these with examples from the Murray-Darling Basin (MDB) experience which many of you have referenced.

In the MDB we have a goal of recovering 2750GL (gigalitres, or billion litres) of water for the environment. This target could be reduced by ~650GL if it could be proved that there would be no socio-economic harm or if we could also achieve the same ecosystem benefits with less water (akin to increased yield from ET savings in the ag sector). For more information see https://www.mdba.gov.au/basin-plan-roll-out/sustainable-diversion-limits/sdlam

As at December 31st 2020, total recovery for the environment was 2106GL, comprised of 1231GL (or 67%) from buybacks and 690GL (or 33%) from WUE (see https://www.mdba.gov.au/progress-water-recovery). But the additional benefits and expected outcomes in support of allowing the 650GL reduction have not materialized, and thus we predict the current policy will eventually fail (Adamson and Loch, 2018) and we will need to ramp up our recovery efforts again.

In that instance, as in the past, to recover water the government will use its two strategies: a buy-back of rights from willing sellers (which has been capped for now based on public ‘backlash’ – despite no evidence of this anywhere); and the subsidization of efficiency measures to generate ‘savings’ as always.
The buyback has always been cheaper; we have absolute evidence of this (Loch et al., 2014) where efficiency can be up to 15 times the per/ML (megalitre or million litres - or 0.81 acre-feet) cost in some cases. In general, efficiency is at least 2-3 times more expensive per/ML. But since folk analytics have prevailed (thank you Glyn Wittwer for this term) buybacks have halted in favor of WUE investments.

The efficiency program was rolled out across irrigation networks (off-farm works), across on-farm technology adoption or practice changes, and across (new) environmental assets such as wetland watering devices. For irrigation networks and farmers, the objective was to subsidize the costs and share 50/50 the water savings, with that 50% of saving being converted to a new right and going to the environment. Ultimately, this water is given to an environmental manager to act in the common good (basically the theory of common property).
In the absence of data (i.e. we didn’t know how much water we were losing and where we were losing it) many heroic assumptions were made on water savings! Further, those who claimed they had the leakiest systems, and therefore provided the best return on the investment, received the most subsidies (again recalling that the cost per ML via this approach may be up to 15 times greater than the buyback). This approach then penalized farmers who had already invested in their own technology.

So yes, we have failed miserably in our efforts to generate water savings in support of the environment, where arguably a lot of the water that was originally flowing (freely) to support ecosystem functions may now be intercepted and consumed providing a total reduction in environmental supply (Adamson and Loch, 2014).
That fact is, we just don’t know either way – there is no baseline or evaluation data.

Further, as (like many of the examples provided above) we manage our systems at a more and more ‘tightened’ level we are certainly increasing our future vulnerability to shocks (Loch et al., 2019). Just recently, we visited almond growers in our Riverland to hear similar stories of using water management to increase yields to record highs, manage pest and disease pressure, and control total growth across the orchard. But as this becomes the norm across perennial industries any return to drought (where by 2050 we are expected to have a 75% chance of dry conditions in any one year!) these systems will be decimated.

We are not (yet) looking at effective adaptation, and without such work we are in serious trouble.
However, the water recovered has been good. Our environmental program is unique. The environmental manager is slowly learning how to manage its assets (environment) with a set of water rights that have temporal and spatial reliability issues; since the amount of water they have to use by location and year is highly variable. Their water rights directly determine the environmental outputs (wetlands, birds, fish, trees, water quality, river morphology, etc i.e. natural capital) they can produce, the assets they can save (in drought) or the systems they can improve (in good years). As they progress their knowledge, and adapt to these seasons, they knowledge is increasing significantly.

But as a sign that some sense may be making itself known, on the 3 March 2021 the Federal Water Minister Keith Pitt announced an end to on-farm WUE programs citing limited or no data in support of benefits from the program—despite millions of dollars now being invested in that space. Subsequent, funding will now focus solely on off-farm investments, see https://www.agriculture.gov.au/water/mdb/programs/basin-wide/water-efficiency.

If you follow the above links we find that buyback is indeed on the table again, supporting the prediction in Loch et al. (2020). Further, the off farm efficiency program is expected to face on-going hurdles on the supply side (delivery networks and dams) according to a recent PC report (https://www.pc.gov.au/inquiries/current/water-reform-2020#report) highlighting the net cost these programs have for society. This may limit what governments can do in that space in future, which again is somewhat promising.

With the current minister an engineer, and with a government mantra of “jobs or bust”, we predict that future efforts to make the environment more efficient will come via bulldozer and environmental irrigation systems. This will end in failure. If this eventuates, then Australia (like elsewhere) will be continuing its pursuit of spin over substance.

The outcome of this spin in the MDB (with the second most variable inflows in the world) will be large scale irreversible capital loss. This capital loss will be financial (on-farm), off-farm (irrigation network suppliers), natural (death of the ecosystems), cultural and social. And the taxpayer will end up paying (again) for it all.

So, as a concluding view and call to action, throughout the world we seem to be in a discussion loop of:
1. WUE doesn’t work,
2. here is an example,
3. we need to stop this approach,
4. Go to 1

We have been working with a range of international experts to try and stop this cycle of spin over substance. A key part requires us to find an alternative to the current mantra of WUE. The problem is that implementation of a new idea only generally occurs when the system collapses. So get your ideas ready to change the processes, yes there will be pain but if there is there is no alternative we hit repeat again.
Finally, we LOVE Richard’s idea about taking all of this and attempting a Nature or Science submission. There is great value in that, if we get it right. And the material here is evidence of great minds/thinking in the space.

References:
ADAMSON, D. & LOCH, A. 2014. Possible negative feedbacks from ‘gold-plating’ irrigation infrastructure. Agricultural Water Management, 145, 134-144.
ADAMSON, D. & LOCH, A. 2018. Achieving environmental flows where buyback is constrained. The Australian Journal of Agricultural & Resource Economics, 62, 83-102.
LOCH, A., ADAMSON, D. & AURICHT, C. 2019. (g)etting to the point: the problem with water risk and uncertainty. Water Resources and Economics, 32, 100154.
LOCH, A., ADAMSON, D. & DUMBRELL, N. P. 2020. The Fifth Stage in Water Management: Policy Lessons for Water Governance. Water Resources Research, 56, e2019WR026714.
LOCH, A., WHEELER, S., BOXALL, P., HATTON-MACDONALD, D., ADAMOWICZ, W. & BJORNLUND, H. 2014. Irrigator preferences for water recovery budget expenditure in the Murray-Darling Basin. Land Use Policy, 36, 396–404.

Thanks for the question François,

In regards to the terminal point of the system the Coorong Wetlands (an optimistic name) the Basin Plan guarantees 650GL of water to the Coorong every year. This is a huge management mistake. As Adam said, it's the Basin with the second most variable inflows, and a fixed environmental target implies that something else must be sacrificed to meet its needs. It's something I argued strongly about when I was commissioned to model flow variability during the development of the Basin Plan.

As Adam said I have a paper I need to finish on all of this but in a nutshell.

• There are 3 levels of property rights in the MDB,
• each catchment has a combination of each right,
• the reliability of each right alters by catchment by state of nature (drought, wet or normal).

In closing, I would like to thanks all contributors for sharing their experience and thoughts on the limits of conventional WDM interventions, and draw a few general conclusions.

While unproductive 'losses' at the plot level should, of course, be reduced as much as possible, and situations of return flows to saline water bodies call for a reduction of these flows, we should acknowledge the implications of the fact that reducing overexploitation and environmental degradation will have to come with a reduction in ET. And this at a time when in many places, such as the Mediterranean Basin, higher climatic irregularity pushes farmers to develop irrigation as an insurance against climatic risk (typical vineyards). The crux of the matter is therefore to regain volumetric control over water consumption and any drastic imbalance will require direct tools such as land fallowing or water rights buybacks. They will, hopefully, gain traction as it becomes increasingly clear that the old panaceas, water pricing and water-saving technology – although they may have benefits (e.g. cost recovery, or raising water productivity) – are not going to do the job. But remember the 2000 World Water Vision: "This Commission has pinpointed two areas that need to be given immediate and high priority if the world is to escape the doom of the current water arithmetic. These are full-cost pricing of water, coupled with innovative approaches to subsidies, and technological innovation." Have we really moved beyond this statement in policy discourses?

As the diversity of water regimes and societal contexts, but also the unforgiving nature of the mass balance, make the upscaling of local solutions problematic, it is tempting to abandon the nuts and bolts of managing water across waterscapes to invest our faith in macro-level economic/market incentives. Indeed change in diets might have an impact (but no country is actively working to boost such shifts and the trend in diets rather runs in the opposite direction), subsidies could support crops with lower water requirements (but it is hard to go against the opposite logic of the markets and state policies that promote high-value crops that are, more often than not, thirsty crops).

Whether such direct responses can be implemented in time seems to be very much a question of faith… very much like our attitude towards climate change. 'Too little too late' vs 'we must and can adapt successfully' ; the 'inconvenient truth' vs the 'many ten percent solutions'. (Who said 'Optimists are always wrong but very much needed; pessimists are always right but are a pain in the neck'?)…