Andernach Geyser

On a wooded peninsula in the Rhine, a column of water shoots up to 50 or 60 metres with no heat behind it at all. The Andernach Geyser, on the Namedyer Werth nature reserve near the town of Andernach in Rhineland-Palatinate, is the highest cold-water geyser in the world, a record entered by Guinness World Records in 2008. Its power comes from carbon dioxide, which works much like the gas in a shaken bottle of mineral water.

The Eifel and the Neuwied basin around Andernach are a volcanic landscape that has gone quiet but not cold. Deep magma chambers that once fed volcanoes still release carbon dioxide, which rises through faults in the rock and dissolves in groundwater. At Andernach that water fills a borehole about 350 metres deep. As it climbs the shaft, the pressure falls and the dissolved gas comes out of solution in growing bubbles, until the gas-charged column becomes light enough to be hurled out of the top. An eruption lasts roughly a quarter of an hour, and the well then needs about two hours to refill before the next one.

The geyser is a human discovery rather than an ancient spring. In 1903 a well was drilled on the peninsula to tap carbon dioxide and mineral water, after gas bubbles had been seen rising in an old arm of the Rhine. The drill struck a gas-rich aquifer and the water leapt about 40 metres into the air. The mineral water bottled here and the fountain itself both went by the name Namedyer Sprudel, and the jet became a local landmark. Today the geyser is one of the sights of the Vulkanpark in the Mayen-Koblenz district and of the national Geopark Laacher See. Andernach, one of the oldest towns in Germany, grew from a Roman fort on the Rhine and keeps parts of its medieval walls and its round tower.

Getting there

The geyser is on the Namedy peninsula, about 3 km from the centre of Andernach, on the left bank of the Rhine. The Geysir Museum lies on the riverbank in Andernach about 2 km south-east of the geyser, and a passenger boat runs from its landing stage to the peninsula. Andernach station is on the Left Rhine railway between Koblenz and Bonn. Cologne Bonn Airport (CGN) is about 49 km away.