Water for crops and water for urban areas. Those are the two global challenges that Professor Nick van de Giesen sees for water management. ‘More and more people are moving to cities, and those cities need water, that much is clear. But what few people realise is that for every kilo of food, you need a thousand litres of water.’
So if you want food, you need water, and with the population of the world growing at its current rate, the demand for water is growing very rapidly too. Van de Giesen: ‘Estimates vary, but by around 2050, we will need to grow between 50% and 100% more food than now. That is rather a lot.’ But Van de Giesen is optimistic that it will be possible. ‘I don’t see that as an insurmountable problem, but we will need to work hard on it, and it does represent the main challenge in my field.’
Nevertheless, agricultural production is feeling the pressure in many places, partly due to urbanization and growing incomes. ‘Even though food prices are very high compared to recent decades, in the Netherlands it’s still difficult to make a decent living as a farmer. At the same time, we can still afford to choose nature rather than agriculture.’ The other options include increasing productivity and expanding agricultural areas. ‘In a country like the USA, you cannot grow twice as much on the same area of land - efficiency is already high.’ Van de Giesen sees two regions where there are still plenty of opportunities. ‘Africa and Latin America will become the food producers of the future.’ But this does not mean that we should destroy major natural areas in the Congo Basin and the Amazon to grow food, he warns. Those areas are important for biodiversity. The surrounding areas of savannah are suitable for farming, however. ‘There is a reasonable climate, reasonable soil and relatively few people live there,’ says Van de Giesen.
When you think of water for food, you immediately think of irrigation, but that is deceptive according to Van de Giesen. ‘Most crops get enough water from rainfall. With better weather forecasts, you can work out the best time to sow seed or harvest your crops. But if you do need to irrigate your crops, you will need to know where to find water reserves and whether you can safely use surface water, for example.’ That knowledge is often lacking. ‘Billions of money will soon be going to Africa to prepare the communities there for climate change. That is strange, because we know almost nothing about how the climate works, so we don’t know what is going to change.’ The problem lies in the lack of data. ‘You can make beautiful hydrological models, but a model makes sense only if you feed data into it and that sometimes gets forgotten.’
The TAHMO project will change all that. TAHMO stands for Trans-African Hydro- Meteorological Observatory - a joint initiative by TU Delft and the Oregon State University.
The aim is to build a network of 20,000 small hydro-meteorological stations in Sub- Saharan Africa. The measurements from these ground stations will be combined with satellite images of the earth in order to build up a comprehensive picture of the hydrology in Africa.
The ground stations need to be robust and affordable, however. That’s why one of the components used in the weather stations is the Disdro, an acoustic rain gauge that costs only a fraction of the price of a commercial rain gauge. The secret lies in the use of an inexpensive piezoelectric sensor, the kind that you find in musical greetings cards.
That idea came from a student five years ago, but the path from idea to finished product is a long one. ‘A proof of concept is only ten percent of the work, that’s what they told us. But even that was probably optimistic,’ sighs Van de Giesen. ‘It depends on electronic circuits; China is the cheapest place to have those produced, but then you have no guarantee of quality. You can also have it done in the Netherlands, but then it is too expensive. And once you have a supplier, you need to test what they have done each time, and often there are months in between. How can you do that for all the components? At TU Delft, we do a lot of research into digital manufacturing, and hopefully that will speed up these processes. We hope that production can soon take place on campus.’
Affordable or not, the weather stations will ultimately need to be financed. Van de Giesen has strong opinions about that.
‘You can make an initial investment as part of your research project, but eventually the weather stations need to be able to sustain themselves.’ One of the goals of the pilot projects recently launched in Ghana and Kenya is to find out how that might be done. But there is money to be made in weather data, Van de Giesen is sure of that. ‘Weather data has tremendous economic value; in the US that value is estimated at over $30 billion annually. So in Africa we must also be talking about billions.’ But this value is a little diffuse, Van de Giesen admits: ‘For us it means, for example - should I cycle to work today or not? Everyone can get something out of that information worth a few euros, but you can’t go around collecting the money from everyone. So here, weather forecasts are typically part of the work of the government. In Africa that’s different.’
So how could you extract that monetary value there? In Kenya, there is ‘Index-Based Weather Insurance’, which allows farmers to insure themselves against drought or floods. ‘The insurance company has a network of weather stations and if no rain is recorded for ten days at a critical point during corn cultivation, the farmers will be compensated for the money they spent on seed,’ says Van de Giesen. ‘As weather stations are not their core business, they could do the same thing using our stations, so that they would not need to worry about maintaining them anymore. That could be done for the same price initially, and if we find more customers who want the same data, that price will go down.’
In Ghana, there is a plan to sell weather forecasts to farmers via their mobile phones. ‘It is often companies that finance that,’ says Van de Giesen. ‘Imagine that you are a large jeans manufacturer and you want to have Egyptian cotton. That is grown in a wide area from Egypt to Senegal. Usually, the harvest is paid for partly in advance. The company would want the farmers to have access to things like credit facilities and reliable weather information.’ The weather stations in Ghana and Kenya will be located next to schools. That will have a number of advantages. ‘They can be used for teaching, which lends some extra legitimacy to the project. And also they will be protected better than if you just placed them somewhere in the middle of nowhere.’
The situation in the Netherlands is very different, you might think, but that is not always the case. ‘Our cities are actually just like the Africa of the Netherlands, that’s how little weather data we have,’ says Van de Giesen. But there is an explanation for that. In accordance with the directions of the World Meteorological Organisation, all KNMI weather stations are sited in rural areas. This is supposed to ensure that comparable measurements are taken all over the world. Cities, however, have their own micro climates. ‘The weather at the front of a building can be different to the weather at the back. That means you have to take an awful lot of extra measurements,’ says Van de Giesen. ‘That doesn’t necessarily have to be done with rain gauges; you can also use radar.’
This happens as part of the European research programme RainGain, for example. Recent advances in radar technology mean that rain radar can measure precipitation on the right time and space scale for urban areas. This should lead to better protection against flooding, including early warning systems and higher storage capacity. ‘Actually, we have quite a strange attitude to water in the city,’ says Van de Giesen. ‘For our drinking water, we collect water in reservoirs in the Biesbosch, then we filter it in the dunes. But the water that falls directly onto the city, we try to get rid of that as quickly as possible using drains and pumps. If you have good rainwater falling, why would you not want to use it?’ But he focuses on the risk of flooding. ‘You want to avoid any damage from flooding because so much economic and human value is concentrated in the city.’
Just how destructive floods can be was shown clearly in Bangkok in 2011, when billions of dollars’ worth of damage was caused by flooding. The idea of the eWaterCycle - a detailed model of all the water on earth - was in part a response to those floods. TU Delft is currently developing the eWaterCycle with Utrecht University and The Netherlands eScience Center. The strength of the project is that it is the first global model that can make water predictions at least ten days in advance and to an accuracy of one square kilometre of land area. ‘We already have global weather forecasts, but no hydrological forecasts yet. You might also want to make predictions about water drainage.’ Governments could use that information to make decisions to limit damage, for example by evacuating people or even by breaking a dike in order to protect an urban area. ‘Some things are more difficult to predict than others, though,’ he adds. ‘Forecasting a tsunami event is very complex, for example, but there is much you can say about monsoon-driven events. And the areas where the monsoon occurs are very populous.’
One country that would definitely benefit from this is Myanmar. And that is a country where Nick van de Giesen can regularly be found these days. After years of isolation, the country has been catching up in many areas, including water management.
Myanmar has significant water resources, but it suffers from annual floods as well as having areas where there is not enough rainfall. In the 1970s and 1980s, many local water engineers were educated in Delft.
TU Delft has been working with Myanmar again since 2013. Van de Giesen: ‘It’s a very beautiful land full of water and the people are very eager to learn. The literacy rate is 93%.’ The long period of isolation has also had some advantages, he thinks. ‘There are a lot of things that they haven’t done wrongly yet.’ For example, much of the water is still untouched. If it chooses the right path forward, Myanmar could soon become one of the forerunners in the field of integrated water management.
Myanmar, Africa... Van de Giesen takes just as much pleasure in them both. He stresses that he really does not see his work as some kind of development aid. ‘Some people do research in the Arctic, for me it is in Africa. Of course, I get along well with the people there and I have my network of contacts, but I’m not going there to show them what to do.
Africa is capable of developing itself.’ On the contrary, there is mutual benefit in the work being done there, and that does not apply to food production alone. ‘There’s a lot there for us as a university too. Just remember the ‘battle of the brains’. Recently everyone has been going to countries like China and Brazil.
And TU Delft is out there too, setting up joint research centres, and that is positive. But there are almost as many people living on the African continent as there are in China. We might have to wait another 30 years until Africa reaches the same stage of development as China, but we could just as well start working with Africa today.’
Published: March 2016