[00:00:22] Bridget Scanlon: I'm pleased to welcome Wolfgang Kinzelbach to the podcast. Wolfgang is a Professor Emeritus of Hydromechanics at ETH in Zurich where he served from 1996 until his retirement in 2014. Wolfgang mentioned to me the other day, that he's currently working on reviewing aspects of the radioactive waste disposal program in Switzerland. So, he is still very active.
Wolfgang has worked in many different aspects of hydrogeology during his career, including water quantity issues and water quality issues. And today, I think Wolfgang, we are going to focus on water quantity aspects and a little bit about water quality concerns talking about the North China Plain and the Tarim River basin in China, and various policies.
Thank you so much for joining me, Wolfgang.
[00:01:12] Wolfgang Kinzelbach: Well, thank you for your interest in my work.
[00:01:17] Bridget Scanlon: Wolfgang, you spent a lot of time in China, I really appreciate the work you've been doing there. The book that you published titled "Groundwater overexploitation in the North China Plain: A path to sustainability" I found it extremely interesting. I like how you describe how the water issues evolved over time. You indicate that up to 2020, groundwater depletion in the North China Plain was one of the global hotspots with declines of about up to a meter a year in some regions corresponding to about 48 cubic kilometers per year. For context, Texas uses about 20 cubic kilometers of water a year. And of course that had impacts on subsidence.
But the main aspect of the book that I really appreciated is how you work with stakeholders and farmers to develop solutions and work with policy makers. So maybe, Wolfgang, you can describe a little bit about how you got started with the book, and then we can go through the different aspects stepwise.
[00:02:21] Wolfgang Kinzelbach: Okay. This Sino-Swiss groundwater project started in 2012 and it lasted till 2020. It was funded by the Swiss Agency for Development and Cooperation, the Chinese Ministry of Water Resources, the Chinese Academy of Sciences and the Geological Survey of China. And from the beginning our idea was to try and stop depletion in order to preserve a sufficiently large buffer of groundwater for times of prolonged drought. The resilience of a water management scheme against hydrological variability is determined by its storage capacity. Aquifers are the largest reservoirs which can bridge years, if not decades, while surface reservoirs are operating on a yearly or at most two-yearly basis.
Now, the two things most people will agree about is that climate change, as we already experience it, is associated with higher temperatures and more frequent extremes. And to adapt to the latter, we need more storage. That's one of the big motivations we had in our project.
Now the location was one particular county in Hebei province, Guantao. There we worked for these eight years. Maybe I should just say a few words why groundwater became so important in the North China Plain.
In the 1970s, the first time I was in China, irrigation was largely done with surface water. And I remember that Hebei province was complaining about water logging and salinization. The terrain is so flat that the water applied to the fields just does not drain away easily. But with the electrification, and the increase in crop production, more water was required and then people tapped groundwater.
Within a short time, the whole problem of water logging was gone because the groundwater table was going down. Which was very beneficial, I must say, at that point. People liked the groundwater. It was easily controlled. No big infrastructure was needed. You just switch the pump on and off You had to pay, of course, for electric energy, but you were still better off for your individual needs and schedule of irrigation. The crop, which really led to the over pumping, that means the continuous draw down of water levels, was winter wheat.
The region has a scheme of double cropping. It's winter wheat from October to May, and corn from June to September. The corn is growing in the rainy season, so it needs only one irrigation in wet years even none.
But winter wheat grows in the dry season, and it has to be irrigated three to four times. In this season, surface water is also rare. Releases by reservoirs do not reach far, and the natural low flow of rivers, if there's any left at all, is basically wastewater. In summer, water is abundant. The question is how to store it. Efforts are ongoing to build smaller storage basins in the plain or store water underground.
Yeah, I would say that was the situation. And now the question is how to stop water tables from going further down. You cannot look at the aquifer system very naively as one big pot. The North China Plain aquifer is a diverse system. It has shallow aquifer parts, and the deep aquifer and they're very different.
The shallow aquifer is the main source for agricultural irrigation. But it is not of good quality. It has three to five grams per liter of dissolved solids. The lower confined aquifer is of much better quality. It's drinking water quality. It's used for drinking water, but it's also used for irrigation in places where the shallow phreatic aquifer is too saline for irrigation.
So, actually it looks like a paradox. The major drawdown is in the confined aquifer below, although the water drawn from it is much less than that drawn from the phreatic aquifer. And it's clear it has to do with the storage coefficient. This confined aquifer can store only a little water. So a little abstraction already makes a big drawdown, whereas the phreatic aquifer is not that sensitive to pumping.
[00:06:37] Bridget Scanlon: I think the trajectory that you described for the North China Plain, Wolfgang, is similar to what the British Geological Survey have described for Northwest India and in Pakistan. They were using surface water a lot in the early and mid 1900's. Then they had salinization and water logging issues in Pakistan. To counteract that, they had this SCARP program and installing wells, but then they over exploited the groundwater in Pakistan. And now they have Recharge Pakistan, so they're trying to recharge the aquifer. So it seemed like we overcorrect and groundwater is very easy to use as you say and you don't have to wait for the canal supplies, and you have more control of it individually.
Wolfgang you mentioned double cropping of wheat and maize. The wheat being really the issue because it's grown in the dry season in the winter and then requiring a lot of irrigation water.
And I was reading and talking to colleagues. It seems China imports a lot of food now. But you corrected me that it's soybeans and meat and stuff. Still, they're growing a lot of wheat, and maybe you can describe the food policy in the North China Plain and how you see that evolving.
[00:07:53] Wolfgang Kinzelbach: The food policy is still very strict for the grains; rice, wheat, and corn. 95% of wheat and corn and 99% of rice are produced in the country and not imported. This is quite an important policy, which is also one of the reasons why it's difficult to stop the overpumping. But in general overpumping is a hard problem to solve.
Why? Because the crisis comes in the long term. And in the short term, you have the gain. So It's short term gain versus long term cost, and these problems are always difficult to solve. The administrator says, I will just pass it on to my successor, and the farmers cannot stop. It is for their livelihood that they are pumping, so you cannot ask them just to stop. And that's why it is difficult to solve.
My friend in China said if people would just die from it, it would've been solved a long time ago, but that's not how it works. It's a very gradual thing and nobody dies from it immediately. You have to get into a certain crisis to wake up and to do something. And I think China has reached that point and something has been done and we see the results already.
So everybody says, all the aquifers in the world are going down, we are in groundwater bankruptcy mode et cetera. That's rubbish. There are fossil aquifers, which can be pumped for another 300 years without any problem. And there are problems in aquifers, where the water table goes down too low and you get to the economic limit of pumping water.
But China, I would say is the first big scale example, which tells you something can be done. The over pumping can be stopped. Of course, small scale examples, we have quite a few. We have the Orange County and Monterey Bay in California. So, it can be done, but on a large scale, we have not seen it, and we now see it in China.
[00:09:42] Bridget Scanlon: When we chatted the other day, Wolfgang, you were describing the context of the North China Plain and the types of farms, the demographics, the age of the farmers, and things like that. Maybe you can describe that a little bit, these very small farms.
[00:09:55] Wolfgang Kinzelbach: Yeah, it's mainly small holders. They have about, I would say a third of a hectare. I don’t know how to calculate that in acres, but you can do the calculation for me
[00:10:05] Bridget Scanlon: Well, a hectare is two and a half acres.
[00:10:09] Wolfgang Kinzelbach: Okay, so we have a fraction of the two and a half acres- maybe a third or a fifth. That’s very little. You cannot get rich on that. What you produce on this land over the year, it cannot make you rich, never. So this is a real problem for farming, this style of farming. And this has to change and it is in a big process of change.
Change from these small farms which are not viable economically to something bigger, to bigger units. When you go to these villages, you look at the farms then you see only old people. The young people notice that they cannot become rich and they go to the city to work.
Old people are there and they're getting older because of China's over aging problem. Does this have a future? It has no future already due to the age of the people. So, what will happen? I have seen some indications of that.
We have also some big farms and it happens the following way: the farmers are allowed to rent out their land for a certain amount, which is fixed to other farmers. This is done sometimes on a very informal basis, sometimes on a formal basis. I know a village where the whole village put the land together to make one big commercial enterprise, and that's also something which is starting to happen.
I have seen these family farms where you go for eating, et cetera on the weekend. They also take land of others so that they become self-sufficient and they can serve food and people can play on that land. So that's something which works and which made income, a viable farming. Now, the farm I would like to describe to you is a farm where they produce seed maize for the whole county.
That's also a big farm, which is put together like a mosaic by renting land from other farmers. This is the one farm where I saw really a young man working with his father. They are using a lot of machinery. They use drones to do pesticide application. They use sprinkler irrigation. They were the ones who were really interested in our project by asking us, "please measure how much we pump. We want to know whether we can save."
This is the future. And the future is even looking a bit more, I would say technological. The modern farmer, in Switzerland or in the US, is a guy who is an engineer. He has not this image of a guy who stands in the field and digs in the mud, right?
He looks at the weather report. He has it in his computer. From the computer, he steers his center pivot irrigation. Maybe he does even better practising what we call precision agriculture. He only puts the pesticides where he can notice with his drone that the bugs are eating the leaves. There are even sensors, which tell you how much nitrate you have in the soil, and then you will only fertilize in the places which are deficient.
So, this is the future where you don't need this let's say farmer who only works according to his experience, but a farmer who is becoming more of an engineer and does it in a more scientific and economic way. This is where things are going. And there are farms in China, which are already of that type, but not in Hebei province so much. But in the Northern province of Heilongjiang or in Xinjiang, big state farms already use this kind of techniques.
[00:13:32] Bridget Scanlon: It's fascinating. I grew up in Southwest Ireland and visiting there last fall with some farmers. They were taking photos of some health problems they had with some cattle and looking up on AI to figure out what was wrong with them and everything.
I think this image of a farmer needs to change and maybe we will get more people into farming. We call it big ag here in the US and I've been to conferences in Nebraska, the Daugherty Water for Food Institute. They bring in farmers to talk about this big economic enterprise, and so they have the big tractors steered by GPS and they can be watching videos or listening to books or whatever while they go through the fields and all of this sort of thing
[00:14:11] Wolfgang Kinzelbach:Yeah, and the automatization is also necessary because of the lack of young people, the lack of workers in the future years. Automatization and robots come at the right time, I would say.
[00:14:21] Bridget Scanlon: In your book you describe, one of the things that you needed to know to manage the groundwater was how much they were already pumping to do the accounting of the water budget. Maybe you can describe how you were able to get the farmers to monitor how much they were pumping.
[00:14:40] Wolfgang Kinzelbach: Yeah. To really understand the water balance in an aquifer, you need to measure not only the water tables, but also the extraction. How much water you take out. The measurement of water tables has been done, not in a very dense way. There is a certain number of stations by the geological survey in Hebei province, which are even equipped with automatic data transmission, et cetera. But then this network had to be densified for our purposes in the county. That was done by our colleagues in the geological survey. Yeah, that is one side.
The other side is, as you say, we want to know how much is pumped and how can you get that number. Now, of course, you can put equipment like a flow meter into every pump, et cetera, et cetera.
This turned out to be difficult. We have done it in other places. We have done it in Gansu province in a place called Luotuocheng, where all the wells were equipped with a smart water meter. Now what is this? This is a thing which is produced in China in large quantities, and it goes on a well, and you operate it with a swipe card.
You get your water allowance on the swipe card and then you pump and then each time you pump and you close down the pump, it is subtracted from your total water right These single smart meters on the wells, they are connected via the internet to a central server so the server can see whether it's operating or not.
It's very critical that this infrastructure is working. If the meter doesn't work and you cannot pump, then the farmers will just kick it away and pump in the usual way, right? They have to repair it immediately. It's not enough just to install that system, but also you have to maintain it over time.
And that was done in that particular place in a very good way. It works up to today, more than 10 years without problems. Why did it work? Number one, it was a private enterprise who put in that system and their income was depending on the system to work, because with the working system the water fee comes in, and then from the water fee, they can do the maintenance.
Now, why did the water fee work, which is not working in other parts of China? The water fee worked because the farms there are not as small as in North China Plain. They're much bigger and several families use one well together. And then for this well, there is the smart meter and they pay apart from the electricity, a water fee, which is bearable. They can do it, it's not too much for them because they have a higher income from their fields. They can pay a water fee and they pay it from the first cubic meter on. Now this is the crux in North China Plain. Number one, the wells are in effect 10 times smaller in pumping rate than in the Gansu province. That's the first thing.
The second thing is these wells are usually so primitive, they're not really equipped to put on this smart meter. They tried to put in smart meters. They put in about 2000 smart meters just the year before we arrived. After three years, only six of those were still working. The Chinese government is very willing to invest in infrastructure, but it is not willing to invest into the maintenance.
The maintenance they leave to the local people, and if they can't do it, the system breaks down. This is the problem and why did it break down? Because it didn't spawn money for maintenance. And the way it didn't spawn money for maintenance is because they could not charge the farmers money.
They drew up a lot of regulations, how to calculate a fee, et cetera, et cetera. But the fee was only for water, which goes above the water right. The water right was already a bit too high for sustainability one must say. And then you go a bit above that. You're still too high for sustainability, but the difference is so small that when you calculate the fee, it was not even worthwhile to go and collect it.
That is why up to today, no water fees are collected. But what is done is the monitoring. And when we found out all these gadgets don't really work, we switched to using energy as a proxy. But if you just use energy, of course, you're not very fair to the farmer who has a deeper water table or a farmer who has less transmissivity or who has an older pump.
To get to the water, we connected the amount of kilowatt hours to the amount of cubic meters by doing pumping tests at individual wells. This was done by my postdoc, Lu Wang who is from the region and who did admirable work in the field, collecting all these data and calibrating the wells by pumping tests.
In the end, we were so far that we had at least in every village or in every well group, at least one test pumping to get from electricity to cubic meters. So this is the first time that we really knew how much the people were pumping. That is what you have to know in order to determine how much you have to reduce.
You cannot reduce without knowing what is really pumped. My biggest success, I would say in this whole project was that the province, the whole province of Hebei liked this approach. They took it up. They even developed a box where you can, at the same time measure the flow and the electricity at the well, and made this whole test pumping much faster.
And this is now the practice done overall. I'm a bit proud of that.
[00:20:20] Bridget Scanlon: I can imagine that's amazing, because you highlight a big issue, it seems like governments and state agencies they're quite willing to put up the capital to install different things or do different projects. They're very slow to provide any long-term funding for maintenance or operations.
We saw it with USAID in Africa and even in the US with the infrastructure law, there was all money for installation and purchasing and all this sort of thing. But no funding for operation. So I think that's a general issue in many regions.
[00:20:56] Wolfgang Kinzelbach: Let me just add one sentence maybe, because what was also happening and which was very positive for the development, is that the electricity firms- , the utilities introduced smart electricity meters. They did it on every well actually.
We know the electricity use very well, even in six hour intervals. We could even look over the day at these data. China is very advanced in all these electrical gadgets. The well looks like Stone Age, but then you have an electric pump in it, and the moment you have that, you are in space age. That is something I have seen a lot in China now. These automatic systems which all work with big data, et cetera, are quite beneficial for the scaling up of observation of, let's say pumping. .
[00:21:45] Bridget Scanlon: Wolfgang, you recently visiting Shijiazhuang, it's agricultural research center where you have a lot of colleagues. It's really interesting all the work they are doing looking at groundwater use and crop production. With all of the monitoring data that you've been collecting within this program, what was one of the biggest surprises that you had? From looking at the monitoring data and how much they're pumping?
[00:22:11] Wolfgang Kinzelbach: Okay. Let me first say if people usually have this idea that these farmers waste water, or even fertilizer. That's not true. In North China Plain, if you put enough water or too much water on the field, it usually trickles down and becomes groundwater recharge. There's very little lost. We only talk about this non utilized or non-beneficial water, which evaporates without going through the plant, which is a waste. It is little.
Also they do deficit irrigation, naturally. If you do the full irrigation you get the maximum yield, if you just reduce by 20%, the yield does not go down 20%. It goes down a little. That is what you call deficit irrigation. And they do this naturally. So we have already farmers who want to save money on the electricity fees and don't exaggerate. So this is what one has to keep in mind. You cannot do much more in saving.
Now the water is already rising in the upper aquifer and it's going down much slower in the lower aquifer. Why? I can tell you there are three components which lead to this rise.
Number one is a very bold scheme, that is the south north water transfer. The south north water transfer solves this problem mainly in Beijing and around Beijing.
Hebei is not taking too much of it, but in Hebei they replace the drinking water wells in the lower aquifer by water from this canal, from the south north water transfer. They put this water for treatment into a water factory. And then this factory supplies the drinking water. So this water is not pumped from groundwater anymore. That is number one.
The second component was measures in the villages. And one was to not plant winter wheat. So there was for a certain amount of fields, not too much because of this demand to stay self-sufficient, right? There was a subsidy. You get that much money if you don't plant winter wheat. This was accepted very positively by farmers because they hardly earn anything from wheat. Usually they cross-subsidize the winter wheat with the gain from the summer maize. So, they switched off this and they took that money instead.
Now you also have a problem of how to monitor this and this we also solved. We solved it by satellite observation. In spring the only thing which is green is the wheat fields, right? You can see them so easily. And of course, you have smog and fog sometimes. But then we use the radar satellites to see the scatter from these little leaves. We had very good monitoring and we even compared, whether it's really the fields which have been subsidized, whether they really have switched off the wheat planting. So this worked and this also a component.
This is interesting in China, before doing a policy, they make experiments. This is societal experimentation. They say these villages do that, and those villages do that. In the end, they compare what worked.
Now, how do you make a farmer save water without letting him pay for the water? They're so poor. You cannot take money out of a naked man's pocket, right? What they did is they gave the farmers in the beginning of the irrigation season a certain amount of money. From that money, the farmer had to pay the water with a normal water fee. And what was left over was the farmers’. So he had an incentive to irrigate less, right? This was an interesting way of introducing a fee without having a financial load on the farmer. So many of these things were tried out. This worked in some villages, it didn't work in others. There's also a mixed reaction, but I think it's a very good idea to do this kind of testing what will work with the farmers in the region.
I talked about the first component, the water transfer. The second component is these many measures, which also included storage basins, yeah? That you have a storage basin, which is filled in the rainy season, and then it gradually trickles down. It's a kind of managed aquifer recharge. We measure these ponds and you find out half of the water is evaporated, but half is going into the aquifer. And also they can be pumped directly by the adjacent fields like a little reservoir. And this was done more and more. I would say it has effects in two ways, right?
You have water, but on the other hand, it takes land area. And this land area is not planted, so it's also not irrigated, right? So irrigated land has been lost to infrastructure that also reduces the area on which you can plant winter wheat, of course. So these things all helped in the direction that water tables are going up.
And the last thing, I think, is the Chinese weather God. he saw that people were doing so well in all their efforts that he said, "Now I will give you a present." And he put on a few big rains in the last years. So I would say one third, one third, one third, is the contribution of these three items to the rising of groundwater tables in the shallow aquifer and further reduction of pumping in the lower aquifer.
There is one thing though, that is unintended consequences, there are houses now which have been built in the time of very low water tables. Now the water table comes up and then the cellar is in the water. These things also happen. I have seen this also in Germany, by the way.
[00:27:46] Bridget Scanlon: Yeah. That's really interesting and I really like that approach where they give the farmers the money at the beginning and then that encourages them to save water. Any money that's left over, then they have it. That's really cool.
And I think another thing you mentioned the other day, you talk about double cropping wheat and maize. One policy to produce enough wheat for the country, but then another policy to reduce wheat production to save ground water.
[00:28:12] Wolfgang Kinzelbach: This policy of subsidies is a bit contradictory. On one hand you introduce a subsidy not to plant winter wheat. On the other hand, you give a subsidy to plant wheat because otherwise you don't have enough wheat, and then there is a subsidy on electricity. I told them, "Why do we do all this measuring? Just make the electricity more expensive then people will use less water!"
But that was taboo, because I'll tell you why the electricity firm was against it. They say, "We want to sell electricity." This is when you have different independent kingdoms within the same country who are opposing each other.
And that is when something has to be said from the very top.
[00:28:53] Bridget Scanlon: And I really like how you described, how you were able to monitor the winter wheat production. So If they say they're not going to grow it, you can see it with the satellites, then if they do or they don't. So that's fascinating. But another aspect that you mentioned Wolfgang was the greenhouses.
I noticed when I took the train from Wuhan to Beijing one time- I couldn't believe all of the greenhouses on the way! And it's not double cropping. I don't know how many times they harvest those vegetables and stuff.
[00:29:20] Wolfgang Kinzelbach: You are right. This is when you asked about surprises I had, this was one of the surprises. I was not surprised at the general pumping rate. That was in the order of magnitude of what you estimate just by plant use. The usual formula, but the greenhouses, yeah, that's a lot.
The greenhouse is conserving water because it reduces the evaporation. Of course, you cannot close the greenhouse. You have to let something out because you have to let CO2 in. Sometimes the farmers have greenhouses where in winter they warm it. The off gas with the CO2 is led into the greenhouse as a fertilizer, right?
Then you would not have to open it to exchange water. Then you can conserve the water. This is nice on one hand but on the other hand, you can grow at any time of the year practically. And that means as you said, it's not only double cropping, it's triple or quadruple cropping.
Of course, you let the soil rest in between, and that is also in the rainy season when you open the whole thing and you let the direct rain from above come down to be stored in the soil.
[00:30:25] Bridget Scanlon: The greenhouses they have there, they're not hugely sophisticated. But possibly, you said they could accommodate. They could use drip irrigation, plastic mulch and other things.
[00:30:34] Wolfgang Kinzelbach: There are very primitive ones. Which are made temporarily from the mud in the field, and then you put this plastic sheet over it. But there are very sophisticated ones too, where all the opening of the aeration et cetera, is done automatically. And there is experimenting. This is a special thing in China, and you have it of course in most developing countries that you have the stone age next to space age, right?
So you have all the spectrum of things one beside the other. And they have very sophisticated greenhouses also hydroponics. I visited such hydroponic farms just recently and they are very good, but they are still twice as expensive as the market outside. The cost is still the limiting thing for that, yeah.
I think in China in general, one must say the food is too cheap. It is too cheap. But it must be cheap. Otherwise the people in the city will make a revolution and the Chinese government is most afraid of that. The farmers have to suffer because they want quiet people in the city. Right?
[00:31:42] Bridget Scanlon: You mentioned in the US we have this community supported agriculture. They talk about farm to table. and subscriptions or share farm's harvest, and I forget the term. I won't try to pronounce the word that you used describing that in China.
So colleagues, your friends in Beijing do that to make sure that maybe no pesticides are used in the food or different things for food security. So maybe you can describe that a little bit.
[00:32:06] Wolfgang Kinzelbach: Yeah, I would say it's an avantgarde. Intellectual people who are mainly worried that their children are getting these pesticides and it's bad for their health. And so, I know some families who are together and they buy from a farmer in the outskirts of Beijing and he guarantees that he does not use pesticides and does organic farming. And then they get the fresh produce inside the city.
I think we have that in Switzerland too. Maybe there is not so much the pesticide problem, but we want to have locally produced food, which is not transported all over Europe, causing a lot of emissions by this transport, right? I think it is a nice thing, but of course you always have to look at the quantity to say whether something is good or helping or not.
This is an avantgarde. It's still a marginal thing in the complete market, but you need the avantgarde to push things in a certain direction. And this is what I sometimes lack in China, that the avantgarde is allowed to speak out. They are too cautious, right? You need these early sensors, which look where the tendencies are and which direction things are going. They could inform you a lot about where to go. For some things it works.
[00:33:20] Bridget Scanlon: It's a pilot testing proof of concept. And so when I was at a conference in Lubbock last year, there were farmers. They're talking about growing vegetables and they didn't have enough water to support a large farm growing wheat or maize or corn, whatever.
So they're growing small plots of vegetables, selling them in the local market. And even the Huffington foundation, we have funding from them. They're, doing this in Colorado, so I agree. small and it's a bit like managed aquifer recharge. These are not huge things but maybe they help. And, they're not probably scalable to a large scale.
Wolfgang, you gave a nice description of the aquifer system in the North China Plain unit, the shallow system, a confining unit, and a deeper confined system. Now the water levels are rising in the shallow aquifer.
Are there any concerns about water quality issues?
[00:34:12] Wolfgang Kinzelbach: Yes, definitely. I would say in 10 years from now nobody's going to talk about this water level decline anymore. The thing is over. It's being solved.
But what happens when the lower aquifer has a larger depression in piezometric surface than the upper aquifer. So the difference in head between the two aquifers has become large. Because the lower one went down faster than the upper upper, so the difference is large. Now, the lower is stagnant or still going down a little, and the upper one is going up. So the difference becomes even larger, and it's this difference which drives vertical water flow. It's little, but over the area it drives water from the upper to the lower aquifer. Now the lower aquifer is drinking water. The upper aquifer is not very good water, not for drinking, it's just barely suited for agriculture. Then these clay layers in between these confined layers, they have even higher salinity.
This would be pushed down into the lower aquifer. So there is this danger, that this wonderful reserve, which should be really reserved for strategic reasons as a drinking water resource, that this may over time be impaired in its quality. So this is definitely something one should watch out for in the future.
That is the next step after solving the quantity problem. Yeah.
[00:35:33] Bridget Scanlon: You mentioned in the shallow aquifer the salt concentrations about three to five grams per liter. We usually talk about milligram per liter, so that's 3000 to 5,000--from gram to liter. Milligrams per liter. Yeah. And so there is concern then to bring that down into the deeper aquifer.
When you have the south to north diversion, then it's really the municipalities and people in towns and stuff that can afford that water. But then by getting them off of the groundwater, that helps the situation.
[00:36:03] Wolfgang Kinzelbach: Yeah. that is why they use this water to replace drinking water, because for drinking water, you can pay more than for irrigation water. But that also limits the scope of how much you can take from the north south water transfer. In the recent years, they had too much water. So what did they do?
They took this water and put it in old river beds. you have these river beds which are dry because all the water has been, stored in reservoirs in the close by mountains. The river bed is the place where you have hydraulic conductivities, which allow the water to go down.
Usually you have fields which on top have a very rich clay soil. It's not so easy for water to go down. It still goes down. Of course, you still have areal recharge in the fields which is quite sizable, But in the coarser sediments it would be preferentially going down. And that is why they put it in these river beds.
And the result was they saw the groundwater tables coming up close to the river. So for the farms close to the river this helps. They can get their groundwater now directly close to the river, but then you're not everywhere close to that river. It doesn't work for the whole area, but it is a contribution.
it's this problem where you don't have what the Chinese called one knife to cut everything, right? It's something where you have to make a mosaic of many different things to solve the problem as a whole.
[00:37:28] Bridget Scanlon: I think sometimes use the expression one size fits nobody.
[00:37:32] Wolfgang Kinzelbach: Yeah. The Chinese saying means one knife. You cut everything with one knife.
[00:37:42] Bridget Scanlon: For resilience then, having a portfolio of things that you can use is good. Some people say if all irrigation was drip irrigation it would be beneficial. But in California now, in other places they're using what they call it flood managed aquifer recharge or ag managed aquifer recharge.
So they flood the fields in the winter when they have the water and then they recharge the aquifer.
[00:38:02] Wolfgang Kinzelbach: Yeah. Excellent.
I mean this happened in China in these big rains inadvertently, and that helped with groundwater recharge. The Japanese are doing this also a lot. Yeah. a good practice and it's not yet that popular in China. Only when they're forced by a really heavy rain. yeah, I agree.
[00:38:21] Bridget Scanlon: One of the other areas that you've done quite a bit of work is in the Tarim Basin in the Western part of China.
[00:38:26] Wolfgang Kinzelbach: Yeah, we worked in the Yanqi-Basin around lake Bosten, which is the biggest lake in Xinjiang. In that place the problem was salinization, we have very high evaporation. You have much natural potential evaporation, very little rain, and then you have to irrigate a hundred percent everything.
The irrigation water was from reservoirs in the mountains. And if you irrigate in a desert area, what happens is the water table comes up. It comes within one or two meters, where the capillary rise will then bring the water up and then you get this potash and salt crusts on the fields, and then they become sterile after a while.
So that is what happened there. They developed a lot of things to leak out the soils by having canals with this different water levels. You feed water in one and you take water out of the other one to flush through the soil and all these things. Then it was proposed, (and I was among those people who were in favor), that we use groundwater.
There is this amount of water which comes up, and it's called phreatic evaporation directly from groundwater. This is a resource which you can use if you push the groundwater table down. We said, okay, "You have to push the groundwater table down." The wells were installed and people loved it.
They loved it. Why? Because you can switch on and off. You can do drip irrigation. If you do drip irrigation with the water from the mountains, it has a lot of sediment. You have to get rid of the sediment in some centrifuge before you can put it in your drippers. Otherwise, they clog all the time.
The groundwater was fantastic. You want to irrigate with surface water, you have to call the dispatcher at the reservoir in the mountains. Then the water comes in big quantities. You don't know what to do with it. You cannot do this more precise irrigation. So that is why they loved the groundwater, and it spread all over the place.
Then of course they overdid it. They did not only use this part of the resource, which is phreatic evaporation, they use more. People say the North China Plain now is almost solved, but the big problems are now there in Xinjiang the over pumping. Yeah. What can one do?
We had a suggestion. In earlier times there was a big movement to insulate to make the canals water tight so that water does not infiltrate before coming to the field. I suggested now together with my friend, "Just tear that out! With the water from the mountains, do groundwater recharge so that people have something to pump."
It's just the opposite of what one has done before. We will see. They have to get into a real crisis so that they will solve things. I think groundwater is this problem where you have to get in a crisis, then you solve it. It's not the problem where people fall down and die. It's the problem where in the end you run into a wall and then you solve it.
It will also be solved there, but it takes still some time to make it hurt enough.
[00:41:30] Bridget Scanlon: and what you just described-- same thing in Pakistan. They were using surface water and they had the salinity problems and the water logging, and then they went to groundwater, but then they went too far.
[00:41:42] Wolfgang Kinzelbach: that's what happened in Xinjiang too. Uh-huh.
[00:41:44] Bridget Scanlon: The other thing that you described lining the canals, and not understanding that, that water recharges the aquifer. I think there are some examples in Murray-Darling Basin Precision agriculture; lining canals and everything, and didn't really take into account that they were losing that recharge.
[00:42:02] Bridget Scanlon: Some differences between North China Plain and Tarim Basin; you described very small farms less than an acre in the North China Plain. In the Tarim basin there are much bigger farms.
[00:42:15] Wolfgang Kinzelbach: These are big farms. You have the farms of the state. And then you have these more privately owned farms and they are also larger. To solve the problem in North China Plain is relatively easier.
Why? Everything which is under the plow is already under the plow. Eventually it's even reduced by infrastructural areas, which are cut away. Now in Xinjiang you have infinite area. It's an area which is perfectly utilizable for agriculture. The only thing it really lacks is water. If you irrigate, you can grow, and that is what is happening.
In year 2000 the Chinese government said it's illegal to turn wasteland into irrigated fields. And you look at the satellite maps, 2000, 2001, 2005, the green patches are growing and growing. So this is the real problem of water and sustainability in Xinjiang. It has taken over producing some things which formerly maybe were produced in North China Plain.
They produce more wheat now. They produce cotton, they produce maize, and they produce wheat. These are the biggest quantities. And of course, tomatoes and these hot peppers! I was standing in these huge fields of hot peppers-- and I asked the farmer," I said, Who can eat that hot food?"
They said " Oh no. This is not for food. This is industrial hot pepper, which is used for the red color of the lipsticks. The Koreans buy it." I said, "Oh, that brand is hopefully called Hot Kisses."
[00:43:49] Bridget Scanlon: How do you see the Tarim basin? You've got the mountains around it which are supplying water from glacier melt and surface water.
[00:43:59] Wolfgang Kinzelbach: There is this whole question of climate change. Yeah. What if the glaciers are not there? All the rivers except for small streams which come from the mountains, are dammed in the mountains. And the dam in the mountain makes sense because it has large depths, small surface area. The evaporative losses are relatively small.
But also we have in Xinjiang some areas some reservoirs in the plain. These will lose two meters, that's the potential evaporation. If they are five meters deep, you already lose almost a half just by evaporation. That is a bad thing. Now these mountain streams being dammed has the advantage that it doesn't matter whether it's rain, which is coming down in the mountain, or snow melt or glacier melt it's all captured in the dam.
Now, if the glaciers are no longer there, the snow is still coming. It is probably increasing. So there is some good prospect of climate change for Xinjiang in the sense that if the Indian ocean is warmer, it evaporates more and more will get across the Himalayas into the Tianshan mountains into Xinjiang and to the reservoirs. it could balance out. Of course, higher temperature means also more evaporation.
So we will see. how this develops. It will put a limit to the amount of area that can be planted. This constant extending of irrigated perimeters is not feasible. It's not sustainable. It has to stop or the area even has to be reduced. Maybe climate change will be the agent, which makes stops the extension.
[00:45:35] Bridget Scanlon:
It is really cool Wolfgang, that we can see so much from satellites these days. Winter wheat or you can see the irrigation expansion. When I was preparing for this, I looked at NASA images of all of the expansion of the greenhouses. These areas were green in the late 80's, 90's, and now they're just all plastic. So It's really fascinating. And I think China accounts for maybe 60% of global greenhouse production.
So anyway, I really appreciate that you spent so much time in China. You've worked with the farmers you get the picture, you're boots on the ground. It's amazing being able to monitor all of this . And how you guys develop that is absolutely fantastic. So people have an idea, we're always grappling with how to get data monitored and stuff like that. Seems like you have managed to do that and scale it up in the North China Plain. So thank you so much Wolfgang for talking with me today.
[00:46:47] Wolfgang Kinzelbach: I thank you for a lively conversation. Thanks a lot.
Our guest today is Wolfgang Kinzelbach and we will also provide the script and highlights and linkages to papers and to his book and all of these other things on the website. And he's professor emeritus at ETH Zurich in Switzerland.
