2022
Sufficient water in the Meuse but is it clean enough
Sufficient water in the Meuse, but is it clean enough?
Can we expect increasing water shortages in the future? Drinking water utility Evides asked Deltares to investigate the situation in the Meuse. For Evides, the quantity does not appear to be the problem, but Jeroen Daniëls, source protection consultant states: "Dry periods and therefore less water in the Meuse do affect the water quality."
For the work of Jeroen Daniëls, source protection consultant at Evides, sufficient water of good quality is essential. "My colleagues and I conduct research, provide advice and check whether our water sources are indeed future-proof," he says.
Evides abstracts around 86% of its water from the Meuse, 10% comes from groundwater and 4% from dune water. In total, 2.5 million consumers and businesses make use of our drinking water, in the south-west of Zuid-Holland, the province Zeeland and the south-west of Noord-Brabant.
“Rapid action is needed to prevent a shortage of drinking water in 2030”, this noted the RIVM in a report in April 2023. The research indicates that due to climate change and contamination, the supply of reliable sources for the production of drinking water are under pressure, and regional shortages are already arising.
Evides wanted to know what this means for the Meuse, and particularly for the Bergsche Maas. This is the location of the water company’s abstraction pumping station for filling the storage basins in the Biesbosch in Brabant. Evides asked knowledge institute Deltares to investigate this in 2022. Deltares was already working on a study into the ‘flow rate', the amount of water running past at a given time, at various locations on the Meuse.
For this, Deltares uses the RIBASIM software developed previously by the Institute. The RIBASIM MAAS model was developed specifically for the Meuse river basin in 2022, commissioned by RIWA-Meuse. The water consumption and water demand of drinking water companies and also industry, the energy sector, shipping and agriculture are included in the model as well. Insofar as the data is known, the amount of water they consume or need is included.
The models helps in assessing the situation. "In periods of drought, you might have to use less water," explains Daniëls. "Say a business needs 10 cubic metres per second and there is only 5 cubic metres. With this model, we can initiate the discussion about the sticking points and jointly look for solutions." This is exactly what the tool was made for.
The model has been used to look at a period of 40 years: from 1980 to 2020. Data from this period has been used to calculate climate projections for 2050 and 2085, explains Daniëls. Based on the climate scenarios from the KNMI, predictions have been made for precipitation, temperature and evaporation, and how much water is expected to flow in the river. "The further ahead you look, the more uncertain it becomes," adds Daniëls. Moreover, the KNMI’s climate scenarios date from 2014. "So we have mainly looked at the hot scenarios, because these correlate somewhat better with the latest insights." This year there will be new forecasts, which will probably be more extreme.
Deltares compared how much water actually flowed past the four monitoring points in the Meuse river basin with the estimates from the model. The measured and calculated flows largely corresponded, so the model is usable for forecasts. It emerged from the research that the probability of a low flow in the Meuse increases in all the climate scenarios.
Probability of low Meuse flow rates
Evides has now obtained a better picture of the probability of low flow rates in the Meuse river at the the Bergsche Maas pumping station. This situation naturally arises mainly in the summer, but the model also calculates how often this probability of low flow happens and how much water there is available. Daniëls: “We wanted to know whether the current infrastructural set-up is adequate to have sufficient water in the coming decades."
Evides also asked Deltares to investigate the impact of very low flow rates in the Meuse. The Bergsche Maas abstraction point lies at a favourable location, Daniëls explains. The abstraction point lies in the delta, guaranteeing a minimum quantity of water: the Haringvliet, the Hollands Diep, the Rhine and the North Sea, at Hoek van Holland, all affect the water level. As a result, Evides basically can always abstract water, based on the amount of water in the river. "The tide causes flow in an inland direction, but the risk that seawater flows past our abstraction point actually proves to be zero with the current sea level."
In case the flow rate of the Meuse becomes very low, water from the Rhine will reach the abstraction point. Thanks to this, the water level at this abstraction point will never be too low. Daniëls: "So even if the Meuse has a low flow rate, enough water will remain available to allow abstraction." The quantity is therefore not a problem at this abstraction station.
The situation is different at other upstream places. Other Evides abstraction points are situated further down the Delta, so closer to the sea, and so other challenges exist here, states Daniëls. Research into the availability of fresh water will be done here at a later time.
The challenge of Evides with the Meuse in the coming years will be more about the quality, states Daniëls. The RIBASIM MAAS model can provide insight here too. You can look at where exactly the water comes from, and based on these locations, make an estimate of the water quality risks, explains Daniëls.
If for example, at a certain location, there is a company that uses water and discharges waste water, there could be contaminants in this. “Or the water is used for cooling and the temperature can possibly increase. If water comes from an urban waste water treatment plant, it could contain pharmaceutical residues and other contaminants. Pesticides could end up in the water from agricultural businesses. You enter all this information into the model, and in this way, you gain a picture of the risks."
If it has only rained a little for a long period of time, the flow rate of the Meuse will lower. "When the water consumption and waste water discharges remain the same the Meuse will consist largely of purified waste water," observes Daniëls. "To put it briefly, low flow rates affect the water quality: contamination will be less diluted. Especially substances with PMT (persistent, mobile and toxic) characteristics will negatively impact the production of drinking water.
It is difficult to predict the water quality, nevertheless, Evides tries to do so, Daniëls adds. "Discharges change over time. Making it difficult to predict incidents in advance. But as a result of climate change, dry periods are likely to increase and therefore the effect on the water quality does seem to be clear."
Using basin stocks during abstraction stops
On average, there are currently around 30 days of abstraction stops annually at the Bergsche Maas, distributed throughout the year. The quality of the Meuse is then too poor to let water into the Biesbosch basins. With a stock of around two months to produce drinking water from, the system can bridge over this kind of abstraction stop, and Evides uses the stock in the basin to produce drinking water.
"An abstraction stop occurs for example when a company discharges substances that we don't want in our tap water," explains Daniëls, "but it could also be due to a fire or a leaking boat. Also, if the waterlevel is very high and the river runs fast and sediment is stirred up, an abstraction stop could be necessary."
Particularly from 2017 onwards, there have been a number of quite dry periods in the Netherlands. Daniëls: "In the case of a low flow situation, meaning little water runs through the Meuse, even a small discharge from a factory can lead to problems. With little water in the system, the effect on the water quality is much greater."
In the meantime, RIVM health guidelines are becoming ever stricter, Daniëls confirms: the allowed concentrations of harmful substances are steadily being reduced for drinking water. This is of course a good thing for health, but Daniëls observes: "For drinking water companies it is becoming increasingly challenging to have the whole system for water production function properly. Especially when you face more frequent abstraction stops that result from a deteriorating quality of the river." He adds to this: "Discharges of undesirable and harmful substances into the surface water must stop. The governments that issue and must enforce the permits for this play a major role in this matter. An idea could be to immediately test existing discharge permits against the current, stricter discharge requirements. The enforcement of existing discharge permits must also come higher up the priority list. Its quite simple, substances that do not enter the water system do not have to be removed in order to make drinking water."
Even if there is enough water in the river Meuse, Daniëls adds: "the general demand for fresh water is increasing. We all want to have drinking water, use products and of course consume food. Industry and agriculture also use fresh water. And at the same time, we can see all kinds of developments on the way: climate change, the rising sea level, more salt water in the coastal areas."
What doesn't help here is the way we have shaped our country, he continues. "Due to the fact that we had abundant water in the past, the Dutch watersystem is more oriented on drainage than it is on storing water, resulting in water shortage starting in spring. We need to organize our water system in such a way that we are able to withstand both drought and flooding, because the latter still occurs of course. He reminds us of the 2021 floods in Limburg, Belgium and Germany. "So it makes sense to allow more space for water in the river basin and retain as much water as possible rather than draining it straight out to sea."
Looking at our water footprint, we are all scarcely aware of how much water we presently consume, emphasises Daniëls. In the Netherlands we use around 120 litres of drinking water per person per day. Whilst our actual water consumption is in fact a great deal more: around 4,000 litres per day. This includes everything we eat and the products we use. For example, to make just 100 grams of chocolate, 1,700 litres of water are needed.
"This is often not mentioned, and it's also quite complex to map out our actual consumption in the water chain properly, because a proportion of these products are produced abroad or go abroad." But, he concludes: "If you want to save water and keep water available for the future, you need to start acting now."