In-situ monitoring of the environmental factors we are interested in, in particular soil moisture, is not as straight forward as one would think. We spent thus quite some time to research different types of sensor technologies and measurement systems that are currently on the market. In the end, we opted for soil moisture probes based on time-domain reflectometry technology to provide us with values for volumetric soil moisture, while also measuring electrical conductivity and temperature. A high-precision rain gauge delivers accurate readings for precipitation data at each of the test sites.
The soil moisture sensors will be targeting the contrast between archaeological features and their surrounding subsurface material, which will help us to understand how relevant environmental factors influence the data quality of each of our surveys. Sensors using time domain reflectometry technology consume quite some energy, which is provided by large solar panels. All sensors, including the rain gauge, are connected via cable to a data hub, which uploads the measurements collected roughly every six hours to a server in the United Kingdom. Through a web application we can monitor the measurements almost in real time, which helps us in deciding the most meaningful points in time for our surveys.