British Cave Monitoring Centre

The British Cave Research Association held its Spring Field Meeting at the British Cave Monitoring Centre, Poole’s Cavern, Buxton in Derbyshire. This was an interesting day looking at cave data logging and graphical analysis of a variety of data. The data collected included barometric pressure, CO2, Radon, air circulation, drip rates and temperature measurements.

There was a trip into the cave to see data loggers and collect data for examination in the afternoon. The session was run by Professor John Gunn and Dr Andi Smith.

They have both spent some time setting up the cave as a National Cave Monitoring Centre to be used by anyone who has an interest in collecting and analysing data from caves. They have the full support of Poole’s Cavern management and access to the site does not involve a caving trip as such as the cave is open to the general public with excellent safe walkways. It is also locked when not open to the public which allows data loggers to be left in situ for long lengths of time in a secure environment.

In the morning there were a series of talks about collecting data from caves, while the afternoon session was taken up by a trip into Poole’s Cavern show cave to view instrumentation and a session in front of the computer in the data collection centre.

Morning Session

John started off the morning with a brief introduction and then Andi gave a detailed talk on why monitoring caves is useful science in relation to climate change. Cave monitoring may be broken down into three main sections.

1. External climate: Rainfall amount / chemistry, air temperature, soil temperature and CO₂ concentration.

2. Cave climate: Air temperature, CO₂ concentration, humidity.

3. Karst and cave hydrology: flow paths, speleothem drip rates, water chemistry.

His talk was based around his PhD thesis conducted in a cave in Matienzo, Northern Spain. He collected a variety of data based on the three points above and had the help of a local ex-pat resident, who was able to collect data on a monthly basis for him. He showed a number of results and graphs of his findings related to past climates and stalagmite dating techniques using the Uranium-Thorium dating technique plus carbon isotopes from drip rates of stalactites.

One particularly interesting finding was that there was a big change in the level of carbon isotope at around a date corresponding to just before 1557. His hypothesis was that it was linked to a historical event. Until that time the Matienzo area was heavily wooded and the trees were cleared around that time to provide fuel in the ports to the north for the production of cannonballs for the Spanish navy (Spanish Armada).

The next session presented by John was on the limestone hydrology of the Buxton area. John showed a series of maps, photos and diagrams explaining this. There are a series of sinks to the west and south of Poole’s Cavern including Axe Hole, Plunge Hole and Leap Edge Swallet while the risings lie to the north at Dog Hole's, Otter Hole and Wye Head.

He explained how the underground hydrology relates to the local geology, especially the orientation of the syncline and anticline axes.

Andi and John discussed how cave monitoring has been covered across the world in a number of sites (see the Cave Monitoring Database website. https://cave-monitoring.org/) but the UK is poorly covered, although some work has been done in Mendip Caves and Stump Cross Cavern, Yorkshire. They went on to explain why we need a British cave monitoring centre:

1. Cave monitoring is fundamental to supporting a  range of cave based investigations: hydrology, palaeoclimate, biological….

2. The most robust cave science projects have long term "cave climate" data to support their findings.

3. It is becoming increasing difficult to set up and maintain cave sites due to funding restrictions.

4. There is a serious lack of continuous, long term data from British caves.

Funding for the monitoring centre has come from BCRA, Buxton Civic Association and Gemini Tinytag who have provided most of the loggers used in the cave. Tinytag data loggers are cheap, made in the UK and accurately monitor temperature, humidity, CO₂ and other environmental parameters. Separate stand-alone loggers provide information on air flow detection in caves especially in relation to understanding of gas concentrations. notably CO₂ and Radon (Rn). John discussed the use of various anemometers from relatively cheap Kestrel anemometers up to ultrasonic anemometers which are much more expensive. 

Afternoon Session

In the afternoon we split into two groups and swapped over between two activities.

1. Trip into Poole’s Cavern to see the location and setup of the various data loggers, while John downloaded some current data from stand-alone loggers. We also collected some data loggers designed by members of CREG that had been placed in the cave earlier in the day. This meant they were able to calibrate their equipment against the loggers already in the cave. The cave is well floored with flags and thoughtfully lit. It has mains power all the way to the end, which is useful for loggers although some use WiFi links to send data through a series of base stations.

2. Session in the data centre located next to the cave entrance. Here is the computer that collects and stores all the data logging information and we were able to look at this and download data. This data is available on the BCRA website.

Finally we all came back together for a discussion and downloaded the data from the CREG equipment and compared it with similar over the same time period from the Tinytag loggers. This showed up a few issues with the CREG loggers. 

A thoroughly enjoyable day. Thanks for organising John and Andi.

Andy Hall

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