[00:00:00] Bridget Scanlon: I would like to welcome Ricardo Hirata to the podcast. Ricardo is a professor at the Institute of Geosciences at the University of Sao Paulo, and also the Director of the Groundwater Research Center there. Previously, Ricardo served as a consultant to UNESCO, the Pan American Health Organization, and the International Atomic Energy Agency, and he was a longtime member of the Groundwater Management Advisory Team (GW-MATE) of the World Bank and Ricardo invited me to a conference last fall in Sao Paulo, and I really enjoyed it. It focused all on aquifers, and it was great. So today we're going to focus our discussion on the importance of groundwater for water resources in Brazil and, with an emphasis on urban areas and drought and, related topics.
Thank you so much, Ricardo, for joining me today.
[00:00:57] Ricardo Hirata: thank you, Bridget, for your invitation. It's a really great pleasure to talk a little bit more about the Brazilian situation, the groundwater, especially groundwater, but not just in Brazil. I think that there is many experience in Brazil that is the same or you can understand Brazil in the focus of South America too.
[00:01:20] Bridget Scanlon: Ricardo, you guys, recently came out of a drought. I guess it extended from 2023 to 2024. And, your droughts, in Brazil are linked to El Nino conditions. And, I was reading, online reports 140, 000, fires in the Amazon and previous and the previous year, 100,000 fires from the International Space Agency in Brazil.
Maybe you can describe a little bit about that drought and, how it impacted groundwater and surface water in Brazil.
[00:01:57] Ricardo Hirata: Yeah, I was speaking about Amazon, the problem in the Amazon that is the largest equatorial forest the planet it's fantastic because it's 2.5 million square kilometers and 70 percent of this forest is in Brazil. It means that, we have a lot of responsibility on the management, of good management of the area.
The problem here is a very complex due to its geography, accessibility is another problem. and the various associated social and economic problems. Recently we have been experiencing pressures due to global climate change, and according to the climate simulation models, clearly show reduced, rainfall, increased temperature.
It means that less water, more evaporation, et cetera, that's affected the water availability in general. But not just for people, but for the whole ecology, The areas drought and fire problems that you mentioned, according to our Institute for that monitoring the situation of fire in Brazil. human activities, including agriculture and mining is causing deforestation which is the base of the many of this problems. I'm speaking about of illegal. Because you have to recognize that, we have, many legal, properties, many legal activities occurring in this vast area, but,there is a lot of, illegal activities. And also, this problem is increasing very fast in the area affecting the problem. the forest cover, gigantic areas, as I mentioned, it's a challenge to control illicit occupation.
It's really difficult to access sometimes the area you have just by helicopters, sometimes, planes, but it's really difficult to find people and find illegal activities in this area. We also had a president, Jair Bolsonaro, who was a climate change denier, in his last administration from 2019 and to 2023, he deconstructed, the monitoring structure and actions, of the police responsible for the region to control illicit activities. It, of course, increased the legality of these activities and by extension, the fire. Another problem in the region of the Amazon is that environmentalists worry that forest loses in the Amazon are causing us the approach of a period of no return, which means that the forest can no longer regenerate by itself.
This would be a very catastrophic, it would be catastrophic not just for the world, but particularly for South America. And, for the country that is, our economy is primarily based on agriculture. No, that's affected the water circulation change completely the climate system in the region, including that in my city is just as is important to mention that the problem is not just related to Amazon, the city that I live in Sao Paulo is 2700 kilometers from the center of the Amazon is really far away. Thanks to the from the Amazon that's traveled through the South America in the south direction. Here in Sao Paulo, it's not a desert where just below the tropical Capricorn and the normally below tropics, you have large desert in the Chilean side you have that the Atacama and the other side in Africa you have in Namibia and Australia.
No, but here in Sao Paulo is very green, humid because of the humidity that we received from the Amazon. It means that it's really linked what we understand the cause but illegal activity is getting worse because now you have people associated with the drug dealers and also, This much more professional activities, not just for the agriculture or just for the pasture to more area.
That's a very complex situation.
[00:06:33] Bridget Scanlon: That's really interesting. so it seems like the legal, aspects become much more organized and professional. And the sheer extent of the Amazon's just very difficult to manage and to police. So during the drought also really impacted river discharge in the Amazon and its tributaries.
And I think when we chatted briefly recently, you were mentioning the impact on transportation and, communities being isolated because they couldn't, move up and down the tributaries. And I was reading, Madeira, which is a big tributary of the Amazon. It dropped from 3.3 meters level 0.5 meters. And, another one Rio Negro, dropped from 24 meters to 13 meters and around the city of Manauss. Maybe you can describe that a little bit, Ricardo.
[00:07:26] Ricardo Hirata: Yes, the impact is very, is really, big issues for us. The level of the river, we must remember that, in the Amazon region, rivers are essential, to the lives, of the poorest population. We, it's a, it's an area that, is more, the population is the poorest population the country
but the rivers, they, serve as transportation routes and provide water and sanitation. and also irrigate crops. That's water, rivers, actually population is really linked with the water. They live together with river, they protect the rivers, but also it really need much more than us, actually.
And a drop of the water level of more than 10, 20 meters, sometimes you have this figures, no, in such a very flat area, because you have to understand that when you decrease the water level of the river, it's a very flat, it means that affect a very large area, in area, in, speaking about surface, no, And that means that the river is far from the home, the people, because people live together of the river, because they fish, they use the water directly, impacted entirely social and the economic chain, and you have to consider that this area is, is area of low infrastructure.
Exactly. Exactly.
[00:08:58] Bridget Scanlon: And so I, I was reading that up to half a million people were isolated, because of the declining water levels in the rivers and stuff. And that's a really interesting point that you make, Ricardo, that in this very flat landscape, then you drop the river level and everything drops.
And the large boats that you use for transportation of goods. fuel, everything is transported by boats and the boat cannot get to the area limited the, not the transportation for the people, but also for, transportation of goods and materials, pharmaceutics, et cetera. or even hospitals, because there is pretty common to have boats that work as service hospitals, Right, and as you mentioned then, with those declining water levels in the rivers, you can also, there was a recent paper that I saw was the impact of Groundwater and El Nino on forest fires in the Amazon. And, maybe you can,talk about that a little bit. Ricardo did that amplify the effects of the drought and result in expanded, fires and stuff because the groundwater levels had also dropped.
[00:10:08] Ricardo Hirata: Yeah, this is a very intriguing discovery, in this paper, that was published the, science of the total environment, this year. Yeah. This research was led by Professor Bruno Kelli. That is one research of our group who, the group or our group identify a relationship in the Amazon Zone, the whole Amazon where when you lower the aquifer level now, the lower aquifer level, there's a correlation with the increased fire in areas with more intensive El Nino oscillation events. It means that it is not just, okay, you have the deforestation, I'll have the. the occupation of the tropical occupation that provoked deforestation.
But also, there is this component of the groundwater because people look like the rain basically, but not from the below that the groundwater, and that there is a very good correlation between the level of the groundwater, the water table, and the health of the vegetation. Because, actually, there is a very intriguing result because part of the water that's a adult tree, takes from the soil It's not exactly the soil. A soil when it's humid because of the rain, but during the drought period, the trees go to the aquifer and they use a lot of water of the aquifer. No, and it means that if you lower the water level, it means that you provoke the vegetation. is becoming more vulnerable for fire.
It means that not just the, and also the big trees also transport water from belowand there is the humidity in the soil is related to this. Flux of the water from the trees from the below to the surface. It means that is really, it's much more complicated the relationship between rain, soil, humidity, river, and also aquifer in this equation about the vulnerability of the fire in the Amazon.
And that's the correlation that we discovered, we established that we are still studying, but it's really interesting about the aquifer is important for the health or for the well developing of one forest. when it's interesting also, because we have studied a lot of eucalyptus trees.
Now, here in the southwest, in the center south of Brazil, Brazil is the second largest producer of eucalyptus, and eucalyptus extracts a lot of water. And one adult eucalyptus can extract 200 liters of water per day. And you have to consider that a plantation of eucalyptus is very dense, All big trees have a lot of evapotranspiration, but the situation of eucalyptus that is really fast, the growing is very fast.
Just in four years you have an adult tree that you have to cut down. And that's it. But the root goes really deep in the aquifer. We found sometimes eight meters below the water table. Eight meters. It's amazing, no? It's eight meters. And it means that they are really using the groundwater for the, for, to supply the tree during the drought. But, It's something that you have to study more to relate and to calculate how important is the aquifer in the total water balance of the green areas or in forest.
[00:14:01] Bridget Scanlon: You raise an important point, many important points there. The compounding impacts of different things. So you have the deforestation. and when I was reading about it, they said, normally when they would deforest an area, And then they burn, they fell the trees and then they burn them. But normally it's humid enough that the fire would be self contained or whatever.
But then during a drought, then it expands much more because the trees surrounding trees are dry and it's not wet around there. And then I guess you've got the intense El Nino events and the deforestation and now recognizing the importance of groundwater and declining groundwater levels.
So as you get all these data, then you have a better understanding and may be able to manage these situations a little bit better in the future, understanding all of the driving forces of these things.
[00:14:55] Ricardo Hirata: Oh, yes. Yeah, I really think that is really important. to incorporate groundwater in this way, because, if you cut off the trees now, it means that you are not just removing the evaporation, et cetera, but also the protection of the forest against the fire. No.
[00:15:16] Bridget Scanlon: And we normally talk about humans with wells pumping groundwater, but when I was visiting Sao Paulo last September and looking at the eucalyptus plantations, it really, I said, these are just the same as the wells that we use for humans. these trees are just pumping it at, at such a high rate and, but we don't usually view them in that way, but we should,
Riccardo, you live in Sao Paulo and the drought we were just talking about was 2023 to 2024, but you experienced a much longer term drought from about 2014 to 2017, that really impacted, I guess about half of the cities in Brazil and, and Sao Paulo was severely impacted because you were so dependent on surface reservoirs and, they dropped off a cliff.
So maybe you can describe that situation and the water sources and how you guys managed the drought and the role of groundwater during that drought.
[00:16:18] Ricardo Hirata: Yeah. It's a very interesting question. And I always like to give an example about how groundwater is important for cities in Brazil. And I mentioned the metropolitan region of Sao Paulo, the cities that I live. Actually, I myself and the 22 million people is very large. Of course, it's a very large area and here the city of the metropolitan area is supply almost 100 percent by surface water. Okay. It means that when you saw the the plans for water security, everything. Groundwater is just a small description of what kind of groundwater you have here, what type of aquifer. But it's just for, it's just literature. It's nothing practical. But actually, our group, say 10, 15 years ago, was invited to participate in one of these plans.
And say, perhaps groundwater can play a better role in this situation. And, and I started to study about groundwater here. Sao Paulo, as I mentioned, supplied very complex system of rivers and reservoirs. Also,we have transfer water from one. two, three actually, three other watersheds to this watershed.
It means that's a very complex, very nice, and provide water for a hundred percent of the population. The service is pretty nice, the quality is nice too, and it works pretty well not during the drought. When we have this very strong, the worst situation in a hundred years, that affect a lot. On the other hand, we the, the total system supply 63-64 cubic meters per second (~ 2 km3/yr).
That's a lot of work. But it should be not that. we have here 10 to 12 thousand private wells is private. Okay. which the other problem is 60 percent of the wells are irregular. It's illegal. It means that they don't have permission to extract. Sometimes you don't have any, we don't have any clue about where the wells are.
And it means that it's really complicated in terms of management, but it's another question or another answer, but okay. Consider that you have it to 10,000 to 12,000 private wells. And that in total, we extract 10 cubic meters per second. That's a lot of water to know it's a huge amount.
It means that the total them region. Actually, the demand is the total demand of water is about 74 cubic meters per second (2.3 km3/yr). Okay. But during the drought that this the drought that you mentioned that worse that you had this, water supply 25% of all our needs. It means that we jump from 1% of groundwater to 25% of groundwater.
It means that, okay, 1% is not so important in terms of big policy, discussion, but 25%. And you have to consider that 60 percent of these wells are illegal, which means that you don't control and also is much more vulnerable because we're speaking about unconfined aquifer and below a very large city industrialized a lot of service gas station, etc.
But it means that the city is on the hands off private wells. it, and also is a very important numbers that the self supply provide. In total, the country, Brazil is supplied, when we speak about the, public water supply, Groundwater is not so important compared to surface water.
You have to consider that Brazil is a very humid country, rain a lot, and, that's the main reason. And, but also engineering decision makers is much more training. In surface water than groundwater. Groundwater for them is a secondary solution, is a poor solution. When I mentioned that, Germany uses 80% of public water supply, based on groundwater, the people say, oh, I don't believe you, because they think that the groundwater is a small, poor solution, is not a well.
Tech, et cetera, that it is, and, but, here, we have a just but the 20 percent of the population is supplied in the public service by groundwater. And perhaps it's one reason that the groundwater actually is not on the hands on the table of the decision makers, because it normally is much more for a small population, small cities, when you go to the percentage of the cities supplied by groundwater, the number, is changed, the number of chains, because, 50 percent of the cities in Brazil is supplied by totally or partially by groundwater. It means that the groundwater serve as a good source for small, normally poor cities, and that's really, important to mention the social,value that groundwater has.
Because we're speaking about a system that is really easy, the well, is easy to use, Normally they work almost in an autonomous way, no? And the cost is not so expensive. And you can train a very fast person for that. It's totally different from a big plant to extract the water from the river, treat the water et cetera.
It means that is the important, but it's not visible for the policy makers and for decision makers. And that's one reason. But the groundwater is also important in this way because, when we had this problem of drought, in this period, we had the, sorry, we had the, that affect 50% of our cities.
50 percent of cities declared crisis, water crisis, just the cities just supplied by surface water was double affected by groundwater. It means that the groundwater was much more resilient than surface water because of the clear reason that we are using a lot of storage. And that's, but it's changing a little bit, but much more for the private sector than for the government, for the public water supply.
[00:23:11] Bridget Scanlon: Right, and you know what you're describing, Ricardo, is similar to what I'd heard when I spoke with the people in Cape Town with the Cape Town drought in day zero, they were 100 percent reliant on a surface reservoir network. And then when the drought hit, they hadn't developed the groundwater system, but everybody and their brother were out drilling wells, with the license or not. And, developing groundwater during the Cape Town drought also. And I guess, you and Stephen Foster from British Geological Survey, you've written a lot of papers about urban water issues and this groundwater supplies. And I guess what you term we use sometimes is non-revenue water. So if the wells aren't permitted and they're not paying for the water, so then the utility the water utilities don't get any funds to develop infrastructure and then you have all that waste is generated that needs to be managed.
So it's a very complicated system to think about,I really enjoyed, and I only got it recently. Your, Portuguese reports and thank goodness for Google Translate
[00:24:25] Ricardo Hirata: Sorry for that.
[00:24:26] Bridget Scanlon: book. Yes. that you published in, 2019, about, groundwater and its importance for socioeconomic aspects in Brazil. And there I think you highlighted, 80% surface water, 20% groundwater. And you mentioned, I think, about two and a half million wells have been drilled for self supply of groundwater in Brazil. and that amounts to, 90 percent of the exploited groundwater is captured through private wells.
And that's about seven and a half billion cubic meters of water (7.5 km3). And in the U. S. we oftentimes use the, the units of million acre feet and, cubic kilometer is similar to one cubic, 1.2 cubic kilometers per million acre feet. Texas uses about all that amount of water, 17 million acre feet. So just to try to give context to these numbers.
so that's, the huge impact on water resources. Then maybe you can describe a little bit how that is divided up among the different sectors, domestic agriculture and things like that. and what role it plays in Brazil.
[00:25:36] Ricardo Hirata: Yeah. One, one limitation that we have, as I mentioned, we have a lot of illegal or irregular wells. Actually, it's one, it's a very difficult to establish or to get, actually good numbers about it. in this study that, you mentioned that we provide one institute here that, Contractors to try to understand the importance of groundwater for Brazil.
You try to use the official statistic, but even, of course, illegal wells are not in official statistics, but even that, with the projections and, a lot of some magic, good magic statistics, but some magic statistics. we established the importance of groundwater. Actually,that's the numbers, sounds and our perception in terms of economy, our perception of when you speak about the sector of a drilling sector, because they are working a lot to drilling wells across the country. And actually, we couldn't see this numbers in more official statistics, but based on the one statistic about the how many farms or how many, who are all, lands using groundwater as the main source. That's a lot. This is 1. 5 million wells. I'm not speaking about dug wells, I'm speaking about drilling large wells, and that will change a little bit the numbers and based on this statistic we change the proportion of the wells because we use much more wells in cities than in the rural areas.
And 2. 5 million. Now, perhaps 3 million and the good thing that now our national agency for that control of water, they use our number and establish the policy based on 3 million wells. That's much more consistent with the reality and the put the ground water in another lab in terms of importance, because we speak about a lot of money to because another thing is how What's the value of this water for the society for, of course, not having this water, what's the impact of that.
And, It means that, particularly, but particularly there are some states that use much more water than others. And the state of Sao Paulo is the most dependent, in terms of water, groundwater in the world. But, another, it means that in general terms today, we can speak that urban uses is much more important, or in terms of volume, this is much more important. And, than in rural areas. But Brazil is a very large agriculture. The agribusiness here is very strong. There's a lot, they are a lot of money and they can go to deeper aquifers like Guarani Aquifer. Guarani is one of the largest aquifers in the world. I think it's one of the biggest 10 aquifers in the world.
It's a very large one. One of the most important in South America, but the, it's a very confined system. It means that in 19 percent is confined. You'll have the Guarani is below,basalt that's confined the system. And. Above this, you have the Cretaceous, sediment that's the Bauru, that's another sediment that's covered the Guarani.
It means that sometimes one well in the Guarani has more than 1, 000 meters there. It means that it's very expensive to get water. You have a good water, good quality of water, low salinity. It's amazing because you are speaking about water that's a fossil water. But the quality of water is impressive. It is a very good for potable water.
And, but the people from the agro business agro, activity, they need water, not just for irrigation, because Brazil has a lot of water and issue use a lot except for orange, for particularly some type of crops. But, they use it for the industrial part, to produce alcohol, sugar and et cetera.
The agro industry or industry associated to the agro, chain that's used also water. And they starting pumping groundwater, and of course it start, we starting getting some conflicts with urban uses of water. It means that the situation Brazil is changing because our economy, of course is growing.
That's nice. But you have to regulate a little bit more, because of the legality, regularity, and also people have to be educated. I'm not speaking about the citizenship, but I'm speaking about the people that takes decision. Like the, in the water authorities, watershed authorities. they have to be educated.
They are much more training to understand surface water than the ground water and actually they are not, they are losing opportunities in a way because you have a still have a lot of water. Of course, you have some problems, local problems of overexploitation, but actually we are use a little water compared to the, our capacity to provide water in ground water.
When you go to places like Sao Paulo, Rio de Janeiro, Belo Horizonte, and the other more metropolitan area, you speak about the surface water are totally contaminated, and you have to provide or treat this water. Okay, but also groundwater is also a good solution. But for me, I think that even for big cities, you have to diversify the system of supply and, the idea of the classical model that the water provide to my home or to my condo is just one provider. No, that's the water company that's, there's just one company that provide water for me. And, my building can have, their own well and use the well, legal well, control the well, but, we can use the groundwater.
You can, reuse the water, from the rain. And it's not necessary to have a very pure water for everything, to wash things, to, to gardening, etc. You can use different waters for different, for flush toilets. No, and I think that for the future you have to put together all the options because the water is getting more and more costly, it's getting really expensive to get water and because you need to treat the water.
It means that I think that you have to change our idea about the water supply, but of course, when you go to groundwater, it means that you transfer part of the responsibility for the users. And also it's necessary to educate these people. That is right. They have the right to use groundwater according to our law, but they need to use in a good way, not just for themselves, because the quality of the, depend on the, partially depend on the well, the quality of the construction, but also the quality of the security for the neighborhoods, because one bad wells or bad use of the ground or contamination of this aquifer can affect the whole community.
That's. It means that's a new time, but it's necessary for, and I think that the university has a lot of responsibility in this equation.
[00:33:33] Bridget Scanlon: I think that's fascinating. And, you mentioned the Guarani aquifer and I think most people, associate, Brazil with the Guarani aquifer and a huge aquifer, 30,000 cubic kilometers of water storage. And as you emphasize, it's predominantly storage because, the recharge area is a very small percentage of the total area of the aquifer, and a lot of that water is extremely old. Trying to manage a sustainably can be challenging is very challenging.
I would like to talk a little bit about the SACRE project when we went out to the field, when I visited last fall, I saw a lot of the aspects of the SACRE project and, it's, I guess it's defined as integrated water solutions for resilient cities, of course, in Portuguese.
I'm not going to try to say it in Portuguese. And you were focusing on the city of Bauru, and you have both surface water and groundwater, and I really enjoyed learning about what you're doing there, 30 people involved, students, postdocs, government people, and everything. I think it's fantastic. so maybe you can describe that project a little bit, Ricardo.
[00:34:48] Ricardo Hirata: Yes, the SACRE project is a multidisciplinary project now that's involved a lot of areas that is really a very, say, many areas together working for the project, and that it's a multi project that the address the development of original research even, and also in the field experiment is not a theoretical one, but you install many pilot studies, in the field and, training, high level human resource.
Because I understand that, this technology has to be incorporated in the industry. And the party is educated the students for that. And, but also it's important for us social communication. So it's in this way that the SACRE project, it's a scientific, the background is really scientific one, the development of technology, using a numerical model, using isotope, using everything that is possible to not just here, but we have a good relation with the universities in Canada and Japan.
That provide us also with other new tech that we don't have access here in Brazil. It means that is a real, scientific project. But also, we are together to try to establish or create our public policies. It means that is a scientific project in X sense, but,to support public policies, through pilot studies, training, high, human resources, and the social communication means that the SACRE is sustained.
In the four pillars that scientific, technology development, public policy training and communication diffusion. It means that, and also I think that the novelty for us in this project that we invite all the institutions that work with water in my state of Sao Paulo. And to join the project.
It means that we are not producing from the university something theoretical or practical. Doesn't matter, but something that's useful. But you are involving people to create together this policy, to create together this technology. No, because they are involved directly in this. It means that, that's really nice.
The secretary of environment that's in our case responsible for the total environment, the agency of, environment agency, the agency responsible for the, permission of the use of water, et cetera. They are here in our project. Of course, the universities Not just in Brazil, but also universities in abroad, Canada and Japan, and also, of course, is involving people from the geological survey of the state of Sao Paulo and geological survey of, federal, geological survey means that, it's a very interesting, experience because,there is a lot of problems,for the different institutions first to work together, because it's amazing that, groundwater is it actually in, in, in a different way in different institutions, like for example, environmental agency, looks like soil and water in terms of impact caused by human activities is contamination vulnerability in not as a source of water and, and vice versa. It means that you have the land occupation. And also one interesting thing that we have people from the hydro economy people know because everything has cost value and cost and that you have to put together sociologists and also people from communication.
That's also important. It means that. We try to get this type of arrangements and also create situations that invite people to stay with us and to participate in this project. For example, at the end of this year of the month of March, the next March culminate in the day of the International Day of War water, 22nd March.
we have a week it is this, Sao Paulo groundwater, international groundwater, week. And, we have a very practical course that you invite people to see, to manage, to touch the experience, ask. about this, about the efficiency in the field directly, discuss this, invite people from,U.
So, we invited people from Canada, Germany, and to discuss best, good solutions in that countries here, and also some political events that invite the major, The presidents of the water authorities, and that's the idea. it's a very challenging one way, but it's a fantastic experience.
And I really enjoyed this type of things. And that's Yeah,it's an ongoing project that we still have three years more, but, we really like to, it's really fun in one terms, speaking about, I'm in research, I'm working for more than 40 years in groundwater, but it's nice, to see the people handing concepts of groundwater put together with the eucalyptus tree or concern about the contamination.
That's really nice.
[00:40:42] Bridget Scanlon: Yeah, I thought the city of Bauru was a really nice field lab, to do this study. population of about, 380, 000 people and they use both, groundwater from the Bauru Aquifer, which overrides the Guarani, and also the Batalha River. And so they use both surface water and groundwater.
And, your studies were showing, nitrate contamination penetrating to depths of about 60 meters. And it was, impressive to see the pilot projects and the students involved in, installing equipment, monitoring, remote monitoring, and all of that. I don't, that is time consuming and expensive that a lot of colleges don't emphasize the field aspect.
And I think, the students gain a lot, from, on the ground experience. And then we also saw that, the direct discharge of sewage and the impact on surface water quality. and I really liked, the economists being involved and, you're looking at a number of different potential solutions.
You're dealing with infrastructure that was installed a long time ago. But what are the trade offs in different solutions? And what are the costs? What's economically feasible? So it's an amazing project. So my hat's off to you for coordinating all of that and then getting all the agencies
[00:42:06] Ricardo Hirata: Yeah.
[00:42:06] Bridget Scanlon: to participate. So one of the things that you do also, Ricardo, is you look at solutions to these problems and one of them I've seen you write about is managed aquifer recharge in Sao Paulo. and there are some studies using satellites and stuff saying some of these aquifers are being depleted, they are acquired and, Bauru, or Acuia, they mentioned in this one study 30 cubic kilometers of depletion.
And so that's a subsurface reservoir then that you could store excess surface water in the ground and help to replenish the groundwater. And other cities like you mentioned in that report to Ribeiro Preto, 100 percent reliant on the Guarani. And and depletion being an issue, and that's a pretty large city, 700, 000 people.
so I think, managed aquifer recharge and other approaches then to trying to manage the groundwater are very important.
[00:43:05] Ricardo Hirata: Oh, yes. And also, I think that our situation, speaking about Sao Paulo, no, but a large part of Brazil. We have a lot of rain during the summer. Summer for us is a lot of water that has a lot of problems with the, in cities also, floodings, this type of things. But also, I, as a hydrogeologist,I, I see this as an opportunity.
Actually, you have to recharge the aquifer and also is possible. But in the case of the cities like Bauru particularly, we have the Guarani aquifer below the base, and you have the basement and you have the Guarani, that's 400 meters thick, and covered by basalt, 100 meters or 50 to 100 meters, and above that you have the, cretaceous, Bauru,aquifer, no?
And that's the package. The city supplies 65 percent from the Guarani, but 25 percent is from the river, from the Batalha river that suffers a lot. It is a small river. Watershed is not so large, but also there's a large, a big competition for water because you have a very, you have eucalyptus, you have a sugarcane plantations that use a lot of water and people, Actually, we run the models and, actually during the drought, you don't during the not drought, but during the period of, no rain, or it means that, winter for us, we don't have water enough and actually the city that is the, at the end of this line, they extract a hundred percent of the river. Actually, when you see after, ah, you saw, no water after. It means that the totally dry river, that's against the law, but, the city needs water. This is the scenario that we are working. But, very challenging because the gu, I need nice source of water, but it's dropping the potentiometric level is falling, Down like one or two meters per year. But the same situation you can find in the Ribeirão Preto, the another city of São José do Rio Preto, large cities or medium large cities that use a lot of groundwater. They put the wells in the center. Of the city or in the urban area more in the central part, and you have a lot of interference because we're speaking about the aquifer that is a have a very large transmissivity means that the cone of depression goes everywhere.
And they'll have of course costs that increase, and also the problems of level. This is one.
Bauru is contaminated by nitrate because not, the city doesn't treat the sewage. but the city, collected the effluent, urban effluent, a hundred percent of the cities is a large coverage in this way.
But it's an old system, low maintenance. It means that we, calculate in 10%, there is a leakage, okay, the total volume that provoked the contamination of nitrate, not just nitrate, now we're speaking about pharmaceuticals, we are speaking about the microplastic that we detect microplastic in, in aquifer too. but the 10 percent of the water, but not from the water supply company. private wells again. We have a 500 private wells that supply additionally the water. When we speak about cities that have problem, has problem, have problem of the shortage of water, it's important people try to use private wells.
But again, we don't regulate the private wells, just part of them. And, work with this, the risk of the contamination of the private wells using a fossil aquifer and, surface water that, provide water and also is the most, the system is not integrated. It means that you have a systems that is provided by groundwater, never has any problem, but is not linked with the areas that's just supplied by surface water because of investment.
The problem water crisis that's affected Bauru is caused by three things that happen together. You have to have three things, not just one. Dropped, of course, is one, but not just dropped. If you don't invest in infrastructure, it means lack of investment or lack of infrastructure is another second phenomenon.
But the third one is management. The problem that you have with the watershed that supply the surface water that supply water for the city is the problem of management. It's much more management than, of course, infrastructure must, but it's management. You have to provide, you have to consider the city is the most important user of the water is mentions in one sense, control the land occupation control for station using eucalyptus that's use a lot of water you can change the crop for no intensively use water.
It means that it's a perfect lab as you mentioned. And this is a very challenging, but also you try using this pilot study using, for example, riverbank filtration system. That is not a common practice in Brazil. It's in the United States, a lot in Germany, a lot in India. But in Brazil, there is some resistance from the government to adopt one system that is, uses part surface, part groundwater, but we have one pilot study using,riverbank filtration.
And, we calculated that is possible to provide the same amount of water of one, deep well that cost a lot because it extracts water from very deep groundwater system. And if you put 10 small wells with 20 meters, very shallow wells, along of the river in the river bank is the same as the last cost a small treatment plant of course and you can provide water, cheaper water than a regular.
In this way we are also speaking about the value, about the cost, about the price of each of the solution. to provide,many solutions, and that the manager can use and establish the best correlation of the best, association of solutions to provide the water. As a big, large experience, we have more than 30, students, mastering, graduate students with, receiving scholarship.
That's also nice. No, it means that they are working a hundred percent for the project and that's a, it's a large group and, but it's pretty exciting in one way. And, yeah, it's
[00:50:28] Bridget Scanlon: Yeah, I was very impressed and with the field experience that the students were getting, the fact that they have full scholarships. So it seemed like Brazil invests a lot. in educating their students and, FAPESP in Sao Paulo and the government. And then also what's impressive is that they support, these students going overseas. We have hosted a couple of Brazilian students in the past. It's a great experience for them, to see other places and what's being done and the government supports that a lot. And you yourself, you spend time in Canada and that helps you network and you still using those networks and those connections inWaterloo, University of Waterloo and other places.
So I, it's really, it's really nice to see. I don't think we have time to, to talk about the World Bank work that you have done and the Groundwater MATE reports, but, I will include it in the website. So people can access them and, and really impressive work that you did with Stephen Foster, through the Groundwater Mate program on the Guarani Aquifer and urban water uses and many different topics.
[00:51:36] Ricardo Hirata: I, I thought they were really nice,easy to read, beautiful graphics and really summarized. I think they were our Wikipedia of the day, Yeah, that's Stephen Foster. He's a very special, guy, hydrogeologist, very well educated, a lot of experience around the world. And he has a very, it's a kind of capacity, it's a guy that, a guy that worked for the, previously for the British Geological Survey. He learned how to make good hydrogeology, but also now he's much more in the management and the strategic view of the groundwater.
He can produce good graphics, maps, and that is pretty easy to read. Not just for us, no, but for the decision makers. And this program of GW MATE of the World Bank was a very nice program that,in total, we were involving two billion U. S. dollars project of the World Bank. No, not, of course, unfortunately, not in groundwater, but the big projects like dams or systems.
And that's, And people in the World Bank, when they, identified some opportunities for groundwater, they call and, they contact us in the GWMATE coordinated by Stephen and that, that's a, we went there to try to get good lessons. And also we produce that publications. That a short text, oh, sometimes there's some books, but normally it is, 10 pages, eight pages focus on management, how to get better use of groundwater.
That is really, I know that some case studies are a little bit, not up to date, but, I think that is a very good literature for understanding, experience around the world.
[00:53:33] Bridget Scanlon: Yes, I definitely think so. And I think, Ricardo, we're recognizing the importance of communicating our science and trying to present it in ways that people can absorb it. and you're working more with journalists now and some of your students are journalists. and I saw that when I spoke with the people, in Jordan and stuff, they are working with journalists, young journalists, and trying to, train them and educate them, so that they can present the work to the public and, to decision makers and, planners and all of these different types of people.
So I think that's really important. so I'd like to thank you so much for, doing the podcast with me and, for Greatly appreciated the opportunity to visit Sao Paulo last fall. Thank you for the invitation and our guest today is Ricardo Hirata. He's a professor at the Institute of Geosciences at the University of Sao Paulo.
Thanks a lot, Ricardo.
[00:54:29] Ricardo Hirata: Oh, thank you, Bridget, for the splendid opportunity to talk a little bit and it's really interesting, a very passionate subject.
