The history of thermal water
There is historical evidence to suggest that hot springs were discovered by the Romans and first used for medicinal purposes between 6 and 16 AD.
Wiesbaden is located on the southern slope of the richly wooded Taunus mountain range in a trough that opens out towards the Rhine and is sheltered from the wind. Around 276,000 people live in the City of Wiesbaden, which lies at an altitude of 100 to 200 m above sea level.
The city’s thermal water and hot sodium chloride springs run at a depth of around 2,000 m from the Vogelsberg mountains to the Taunus mountains via Wiesbaden and towards the Rhine / Rheingau. In Wiesbaden, the water flows through a crevice at a temperature of 67°C and runs through the Neroberg hills towards Taunusstraße, Kranzplatz and Platz der Deutschen Einheit. The last monitored borehole is in Assmannshausen, where the water still has a temperature of 22°C.
There is historical evidence to suggest that hot springs were discovered by the Romans and first used for medicinal purposes between 6 and 16 AD.
A Roman fortification was built around the hot springs with a settlement named “Aquae Mattiacorum”.
The springs of the Mattiaci tribe in Wiesbaden have become a globally recognised remedy ever since their great value was lauded by Roman naturalist and writer, Pliny the Elder, who was stationed as a soldier in Mainz around 50 AD, in the chapter of his encyclopaedia entitled “medicinae ex aquatilibus” (“Remedies in Water”).
The hot mineral springs actually comprise 21 secondary springs and 6 primary springs, some of which are privately owned. In 1952, some springs were freshly drilled to prevent major contamination to the thermal springs in the city centre. The boreholes are between 60 and 115 m deep.
The hot medicinal springs are located in a protected area, which is officially monitored by the municipal authorities in Darmstadt in cooperation with the Hessian Geological Office.
Every day, over a million litres of hot mineral water gush out of the 26 thermal springs in Wiesbaden. Geologists believe the springs to be at least 200,000 years old – but they might have been formed much earlier. What we do know is that they’re some of the hottest springs in Europe. The temperature of a 27th spring, the water of the Faulbrunnen fountain, is only 18°C due to the influx of groundwater. As a result, it is no longer counted as one of the city’s thermal springs. With a total of around 6 to 8 grams of dissolved mineral salts per litre of thermal water, the table salt content is around 4 to 6 grams. That’s why the thermal springs are often referred to as sodium chloride springs (table salt).
“mattiaqua: springs – pools – leisure”, an initiative launched by the City of Wiesbaden, is the largest holder of rights to the local springs and runs two thermal baths, Kaiser-Friedrich-Therme and Thermalbad Aukammtal, with thermal mineral water from the five main springs (Kochbrunnen, Salmquelle, Schützenhofquelle, Große Adlerquelle and Kleine Adlerquelle). mattiaqua owns 16 thermal springs, five of which have been removed and four have been decommissioned. It also operates drinking water points at the Kochbrunnen, Bäckerbrunnen, Schützenhoftrinkstelle and Faulbrunnen fountains. These fountains are subject to the Mineral and Table Water Regulation and are officially monitored by Darmstadt Regional Council. The water is classified as an over-the-counter medicine according to the German Medicinal Products Act (AMG) and the owner is obliged to conduct stringent microbiological examinations with the help of pharmaceutical specialists. The microbiological tests are carried out by “Hessenwasser”.
The water temperature
There is a steady rise in temperature from the surface of the earth to its core. It gets around 1°C warmer every 33 metres. According to geological calculations, the thermal water in Wiesbaden therefore comes from a depth of at least 2,000 m.
However, it is also conceivable that the hot rock zones located 30 to 40 km beneath the earth’s surface make a significant contribution to the constant warmth of the thermal springs.
The water is enriched with carbonic acid from magma chambers that are yet to fully solidify and are presumably found deep beneath the Taunus. Calcium, magnesium, strontium, iron and manganese are released from the rock.
Wiesbaden’s thermal water is very salty – although the reason for this high salt content is still a mystery. The thermal springs are the source of hundreds of kilograms of table salt.
Composition
Salinity: 4 to 6%.
Main constituents: sodium, calcium, iron, manganese, arsenic, anions, chloride, hydrogen carbonates.
