Did you know that even rivers have their own days? Since 2004, 29 June has been known as Danube Day. The International Commission for the Protection of the Danube River (ICPDR) and the European Union both support this special occasion. This river is the second-longest river in Europe and the longest one in the European Union, flowing through the territory of ten countries, including Slovakia.
International Danube Day
Máte problém s prehrávaním? Nahláste nám chybu v prehrávači.
The Slovak Hydrometeorological Institute, with Czech and Austrian experts, prepared a joint measurement of the river's flow. Mariana Palková met Daniel Košt'ál, a hydrometeorologist, at the gauging station below Devín Castle. What does such a measurement look like?
We use ultrasonic equipment to study the flow of water. We want to find out the relationship between the height and the amount of water. Since we are not yet able to monitor the volume of water separately in this area, it is essential for us to map the relationship between these two parameters. We will then study the hydraulic regime at the gauging stations.
I also experienced the whole metering process with the ultrasound machines on the boats. However, the tourist ships to Vienna also cause problems with the readings. To ensure accuracy, the staff at the meteorological institute have set a point from which the monitoring starts.
The instruments simplified the procedure. They work on the principle of tracing, so we know the exact position. The device goes from one bank to the other. But we have to make several rounds. Based on this, we take an average of the measurement. That's how you get the final number.
There are a total of 417 water gauging stations in Slovakia. According to experts, the station in Devín is the most important. As Daniel Košt'ál says, other forecasts depend on the data from this area, especially for the ships that regularly use this route.
One of the factors that is closely monitored is shipping traffic. It has its own rules about the height of the lowest or highest navigation level. The Danube is an economically important river, so we have to take careful measurements. As a result, other transport or energy planning is also conducted.
The meteorological service also frequently issues flood warnings. Heavy rainfall a few weeks ago caused significant problems in Slovakia. In several municipalities in the northeast, mayors declared a third level of flood activity. That's when cooperation with international centers is essential, says Daniel Košt'ál.
In Bratislava, flood protection is currently good. However, we cooperate closely with colleagues in neighboring countries. In case of heavy storms, we can see in real-time how much water will reach us. It is important to note that rainfall in Slovakia does not affect the Danube. Bigger problems are caused by melting glaciers, landslides in the Alps or spring thunderstorms.
The floods on the Slovak section of the Danube originated in the Alpine tributaries of the Bavarian and Austrian Danube. The biggest flood in the last 500 years occurred in Bratislava in August 1501. Bratislava now has good protection against flooding, but this was not possible in the past, so the river regularly caused problems in the city.
Historic Bratislava had almost no flood protection. The level of the Danube regularly rose and overflowed into the city. Residents faced the risk of floods directly into the town centre. Especially in spring and summer. The last major flood in Bratislava was in 2013 when we measured more than 10,500 cubic metres of water per second, which is a lot.
The opposite problem is excessive drought. Hydrometeorologists distinguish between different types of aridity. However, they consider the intensity of the dry season as the key fact.
There are different scenarios of how scarcity will affect people's lives. Experts are not worried that drought will lead to widespread drying up of waterways. However, water should be valued and treated as a treasure.
But how do we treat this treasure? The Ministry of the Environment is responding to the amount of plastic found in rivers. According to the latest research by the University of Vienna, the Danube washes more than four tonnes of plastic into the Black Sea every day. In addition, for several years, there has been more plastic in the Danube than fish spawning. The ministry adds that this has an impact on the entire ecosystem and human health. Up to 75% of the world's population consumes and absorbs protein from aquatic animals, which can ultimately lead to a range of health problems. Barbora Micajová, a surface water quality specialist, points out that the situation has improved in recent years. According to the annual monitoring of stream pollution in Slovakia, the Danube is in good condition.
The water quality in the Danube, especially here above the city, is comparable to drinking water. Of course, this does not mean that we should drink it. The Danube has a large flow, and therefore the pollution is diluted by the huge amount of water. Nevertheless, water pollution is still a significant issue and should not be underestimated. We also have to bear in mind that any traffic accident can happen and cause huge contamination.
Especially municipalities in Slovakia are struggling with the drying up of smaller streams. But they also have a second problem: high levels of chemicals in the rivers. Barbora Micajová recalls her research in a small village in the Trenčín region.
I once investigated the water quality in the village of Vršacké Podhradie, a very beautiful hilly area. You would think what a lovely place. But the stream that ran through the village was in very bad condition. I didn't expect that. It was a small creek that could be polluted very quickly. As the locals had no public sewerage system, they poured whatever they could into the water, and the contamination was enormous.
Among Slovakia's major rivers, the Nitra is the worst off, according to researcher Barbora Micajová. It has long been one of the most polluted waterways in Slovakia. Most of it is in the upper reaches and its tributaries.
This is a very agricultural area, so we regularly find high levels of nitrates and phosphorus. Its quality is greatly affected by the use of fertilisers and chemicals.
She also points out that it is forbidden to dump waste in rivers in Slovakia, especially for the locals in the villages.
If you do not have a permit, you are not allowed to release anything into the adjacent water. This is an issue that should be addressed by the state. Urban drainage is a priority in this topic. At the same time, we also need to keep the countryside around us clean; this should be the role of education," concludes Barbora Micajová.
Concludes Barbora Micajová.