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SLOVAK CITIES BENEFIT FROM USING RAINWATER (Slovakia)
All cities and towns will face the need to reduce the negative impacts of climate change by sustainably using precipitation. A green roof at a school, a fountain in the city, or a raingarden — these are just a few examples of how rainwater is used in Slovak cities. For municipalities, the economics can also be a motivation.
We all pay for rainwater drainage, or sewerage, whether we use it or not. In Slovakia the use of rainwater is more a matter of ecological understanding than an economic issue. “Water prices are regulated, which means that people pay to drain water from paved areas. However, the amount paid still too small to motivate people to think about how to use this water,” said Martina Paulíková, program manager of the Water Competition at the Ekopolis Foundation.
While for single-family homes and apartments, the amount is in the tens of euros, municipalities and large companies pay much more for this levy. That’s when the use of rainwater starts to get a little more interesting. According to Paulíková, the city of Zvolen should pay 150,000 euros a year for water running off its paved areas, such as sidewalks, roads, and roofs. Figuratively, this money goes down the sewer along with the water. We know better uses for it, whether as a household, municipality, or company.
Even though Slovakia does not yet have a shortage of drinking water, the use of rainwater as an alternative in cities is reasonable. Climate change is slowly making this a matter of course. The city of Levoča is looking at this reality and has created a project to collect precipitation. “The construction of water-collection measures will mitigate the negative impacts of climate change in the environmental, social, economic and security spheres,” said Zuzana Beregházy, project manager from the Levoča Municipal Office.
NO WASTING DRINKING WATER
The project will be carried out around the hospital where there is currently no storm drain, and the water is being diverted into the public canalization. The project report states that “part of the rainwater may be used for the maintenance of the greenery around the hospital. In addition to capturing rainwater in a collection tank, a rain garden will be built on the hospital premises”.
The capture of rainwater relieves pressure not only on the consumption of drinking water, but also on the pipes and wastewater treatment plants in cities. In Slovakia, we have a common, unified sewer system for rain water and for the so-called “black” sewage. When there is more rain, the sewer system simply cannot keep up. It is designed for a certain population and a certain amount of water. “With torrential rains, water engulfs the sewers and can wash out the treatment plant. It washes out the bacteria that break down the sewage and it thus becomes dysfunctional,” Paulíková said.
That is why so-called relief chambers are used in cities. These are tanks that discharge water directly into the river, but also with all the sewage, such as toilet paper. This scenario is also not ideal, and that is why steps are being taken to use rainwater. “The capacity and flow of wastewater treatment plants, as well as public sewers, is limited, and according to statements of the PVPS, this has to be addressed by customers or producers in a different way,” said Richard Friga, head of Customer Service at the Podtatranska Water Operations Company (PVPS).
RAIN GARDENS IN SCHOOLS
One option is the retention of water in the form of a rain garden. Such projects can be implemented to good effect on school grounds, where the educational dimension is also realized. It increases land with permeable soil, drainage, and plants to capture rainfall that flows from paved impermeable surfaces such as roofs, pavements or playgrounds.
The Technical academy in Spisska Nove Ves has such a garden already — it captures water directly from the roof of the gym. According to the project report, the garden is able to capture more than 11 m3 of water and the rest is drained by a safety overflow to the sewer.
This was a pilot project, but they plan to continue using precipitation water in other ways in 2021. The plan was made clear by Peter Malučký, deputy director of the Technical Academy: “The water will be captured by the vegetation on the roof itself. During times when there is more precipitation, it will be captured in retaining tanks and used during drier periods to maintain vegetation on the roof as well as the school park.”
As advantages of the project, he mentions the cultivation of the environment, the pedagogical dimension, the economy, and reducing the burden of diverting rainwater into the public sewer system. The disadvantage might be demanding maintenance of the precipitation capture system.
WATER FOR FOUNTAINS OR FOR IRRIGATING GREENERY
The city of Spisska Nova Ves does not have such water capture measures. There are several reasons. One of them is the extensive historical area, where underground facilities cannot be housed. Another reason was clarified by Tomáš Hamráček, Head of Municipal Service, MsÚ: “The town of Spišská Nová Ves participates in PVPS and therefore has significant relief from sewage payments. So from an economic point of view, it’s not that interesting for the city.” However, for watering urban greenery and sprinkling road surfaces, the city uses water from the Hornád River. The pump station is set up on Sadová Street, from where the water is pumped if necessary.
Although the city does not directly use rainwater, it supports projects in the surrounding area. “The city provided land it owns for free to Hnilec County, creating good conditions for their implementation of water-capture interventions,” said Darina Paveleková, head of City Development. In the words of Hamráček, the city is not standing in the way of future projects for the capture and use of rainwater in suitable locations.
The use of precipitation water has several advantages. Its retention positively affects the local microclimate, supports the small (local) water cycle, and helps combat drought. In addition to environmental benefits, it saves water and sewage costs. The fact that it reduces the consumption of drinking water, which is becoming increasingly precious due to climate change, is significant.
