Pilot area activities – #6 Groundwater monitoring in Girona, Catalonia, Spain

Installation of new monitoring networks to assess shallow geothermal energy resources  

Shallow geothermal energy for heating and cooling in Catalonia has been growing fast for the last 5 years. The city of Girona (NE of Catalonia, Spain) is an example of an urban area with high potential for its deployment but up to now, the market is poorly developed. In order to assess and map shallow geothermal potential for open and closes loop systems, the Geological Survey of Catalonia (Institut Cartogràfic i Geològic de Catalunya, ICGC) is working in the area to characterize the geological, hydrogeological and thermal baseline conditions. A monitoring program has been set up defining two networks with a total of 22 observational points:

a) The primary network consists of 11 newly drilled boreholes 100 m deep, which are instrumented and equipped with telemetry. In all boreholes, line-string temperatures sensors measure the underground temperature at different depths (18 sensors per borehole). 6 boreholes act as open piezometers with water level and temperature sensors, to gather information about the groundwater. The other 5 are equipped with simple U geothermal probes, 32 mm in diameter. Thermal response tests (TRTs) will be carried out between January and February 2020 in these borehole heat exchangers.

b) The secondary network corresponds to 11 piezometers and water wells with installed water level and temperature sensors for automatic measurements. Additionally, temperature profiles are measured manually throughout the length of the wells on a regular basis.

All data provided by the networks will allow characterization, modeling and mapping the shallow geothermal resources within the existing aquifers in the pilot area.

For more information about the survey, please contact:
Ignasi Herms, ignasi.herms@icgc.cat

Left: Map with the location of the networks. Right: Drilling the new boreholes.
Left: Groundwater temperature measurements (December 2019). Right: In situ semi-distributed thermal response tests (January 2020)
Monitored temperature trend along a semi-distributed thermal response tests (January 2020)

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