Artesian water is some of the purest and highest quality water in the world, so for Káraný this is a precious source, even though it is its least abundant (producing about 50 l/s). This groundwater lies stored at great depths, ranging from around fifty to as much as several hundred metres, where it slowly percolates through pores in the sandstone and conglomerate layers that have held it for thousands of years, enriching itself with minerals along the way. Dating by hydrologists and hydrochemists indicates a very surprising age for this artesian groundwater – it is estimated to date back to the end of the Upper Palaeolithic, 14–15,000 years ago. It is safe to say that this groundwater has never come into contact with human civilization, and nothing on the surface can have contaminated it.
In total, seven wells are used here, with depths of between 60 and 80 metres, and abstraction of this water must be regulated to prevent the depletion of this valuable resource.
Despite its prized quality, artesian water also contains large amounts of dissolved iron, and we need to get rid of that. This is accomplished by a process of intense aeration, followed by removal of the precipitated minerals using sand filters. Along with its supply to the distribution network, artesian water is also packaged in bags for use in emergencies, which is a unique service provided by PVK in the event of drinking water supply failures or disruptions.
Artesian water is unique because of the way it is geologically stored, enclosed in a layer of permeable rock that is sealed from above and below by impermeable layers. When we drill down through the impermeable layer, the water rises up to a level where it is discharged. This type of well got its name from the former county of Artois in northern France, where this phenomenon was first recorded, but wells for artesian water were already known in ancient Egypt, and can be found almost all over the world. A number of spa towns in the Polabí region along the Labe (Elbe) River use artesian water (e.g. Poděbrady and Toušeň).
...artesian water is so ancient that it contains no micropollutants from human activities?
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