A real-time underground environment monitoring system for sustainable tourism of caves

In this paper, a real-time monitoring system is presented to be used for environmental parameters measurement in tourist caves that can be employed for getting a sustainable tourism. The system allows the registration of a lot of metadata (temperature, relative humidity, wind speed and direction, CO2, atmospheric pressure, rain, presence and visitor count) and it shows them via the Internet in real time anywhere. The system reports the data registered and stored as metadata in a database online. In the "El Soplao" Cave in the North of Spain, this system, permits a high level of control and security of the influence of visitors on a day to day and the temporal evolution to medium and long term. These measurements allow developing a sustainable and profitable system where heritage management and tourism exploitation acquire a subordinate commitment to the welfare of the natural asset (Cave-Mine "El Soplao"); the alteration of the fragile microclimate inside the cave can damage or destroy the specific geologic formations that make the touristic cave. After the visits, the company managing the cave takes in charge monitoring the environmental parameters of the cave to regulate future visits. The temperature in the cave has ranges between 11 and 13.5 degrees C, a seasonal quasi-periodic maximum variation of +/- 0.5 degrees C and depending on the temperature outside the cave and number of visitors; it is difficult to associate one with another because both happen in the same month. The relative humidity is around 70-95%, it has no correlation with the number of visitors accessing the cavity. The CO2 concentration in air is around 400 -1000 ppm; it has a clear correlation with the number of visitors and cave area (the deepest present's higher level CO2). In conclusion, a cave is visited as long as its microclimate is maintained, thus the realtime system developed has been conceptualized for monitoring over time the relationship between the cave environment and a sustainable tourism. Monitoring can help to preserve the specific geologic formation and therefore to keep the touristic interest of the cave. (C) 2016 Elsevier Ltd. All rights reserved.