Bath is a spa town, built by the Romans around its hot spring waters around 2,000 years ago. For centuries this natural phenomenon has attracted visitors to Bath, and resulted in a unique historic urban environment, beautiful Georgian architecture and resulted in Bath becoming the UK’s first World Heritage City.
The thermal waters rise from a depth of about 3000m at a rate l.l million litres/day and a constant temperature of around 46C. These waters originated as rainwater which fell on the Mendip Hills between 10— 80,000 years ago. They reach the surface in three places in the city centre, and baths have been built over each one. The water is heated by geothermal action and these springs in Bath emerge at the highest temperature of any water in the UK.
The Saxons and Normans made use of the hot mineral waters for curative purposes. By the late 16th century there were baths attracting the poor and leprous to the city’s hospitals and almshouses in search of healing and relief from discomfort. Visits to the city’s baths by members of the royal family and the court during the 17th century helped establish Bath as a fashionable watering place. The "Pump Rooms" were the Victorians' addition to the Roman Baths. The Victorians re-discovered the Roman Baths and they have since been restored to a magnificent condition.
You can pay to walk round the baths in the Roman Baths Museum, the entrance is on the opposite side of this building. This is an excellent museum which we have visited recently and is suitable for all ages. You don’t have to enter to complete this Earthcache but it is highly recommended. More details are on this website www.romanbaths.co.uk/.
You can bathe in the hot spring water at the Thermae Bath Spa. These impressive baths are a lovely experience but are rather expensive, details here. www.thermaebathspa.com/ Booking is essential.
Rainwater falls in the Mendip hills around Bath which are composed mostly of Carboniferous Limestone. As the water travels through the rock it dissolves minerals from those limestone rocks giving the waters the mineral content which has so many claims about it’s benefits. The water has been analysed and contains 42 different minerals and trace elements.
Over thousands of years this water reaches depths of around 2.5km below the earth’s surface where the temperatures are much higher. This variation of temperature from surface to deep inside the Earth is known as the geothermal gradient (which is approximately 26C / km depth) and the water is thought to reach temperatures of around 64-96C.
As the water temperature rises this causes it’s pressure to also rise. The high pressure pushes the water back up a local geological fault in the rocks called the Pennyquick Fault. The hot water emerges in three places in the city at a temperature of around 46C.
Bath Abbey finished an innovative project in 2021 to use this geothermal energy to heat the building (which was built in 1611). Excess hot water is channeled from the Roman Baths through the “Roman Great Drain” to the River Avon. The water in the Great Drain at this point is around 35-37C. Some of the energy from this hot water is used in underfloor heating of Bath Abbey through a closed loop heat exchanger.
In order to log this Earthcache please send the following answers to me through the message system:
- At GZ in the side street there is a stone plaque on the wall. What does the plaque say about the first use of these Hot Springs?
- What physical processes do you think cause the hot spring water to cool in the Roman Baths? Remember that the Baths have a fairly steady bathing temperature of around 34C whilst the hot water feeding the Baths emerges at a temperature of 46C. List as many physical processes as you can (there are four main processes, not including the human designed mechanisms which regulate the temperature of the baths). Hint for the main cooling process: the Roman Baths are outside and sometimes you can observe a major factor from GZ (the colder the air temperature, the more obvious this is).
Feel free to log this Earthcache after you have sent your answers, please attach a photo to your log with shows the entrance to the Roman Baths on the other side of the building with EITHER:
- Yourself - a Selfie OR
- Something showing your caching name (eg written on paper)
Do NOT post a photo of the plaque or answers to the above questions in your log. Any logs with this information will be deleted to prevent cheating.
Top tip: You can pay to drink the spring water in the Pump Rooms Tea room.
Don’t.
It’s foul.