Setting up the first monitoring station

All five moisture sensors are inserted into the section of a posthole at Hovland - ready for in-situ measurements Foto: Petra Schneidhofer

How we set up our first monitoring station at Hovland and why duct tape was of the essence!

The covid-19 pandemic has also impacted our project. As a consequence, we had to wait a little longer for our monitoring equipment to arrive before we could start the installation process, plus we had to conduct the set-up all by ourselves. Luckily, this was no problem due to the great help we received from our equipment supplier Vincent VanWalt and his team at VanWalt Ltd, who prepared and set up the different components of the monitoring systems in the UK before shipping it to Norway and - once everything had arrived - assisted us via skype and phone.

The first monitoring station was set up over a large building structure at Hovland, close to Tjøllingvollen. The site was discovered only last year during one of our GPR autumn campaigns, after we had been tipped off by dedicated metal detectorist Sverre Næsheim, who found a rare Gullblikk at the site. We thus knew relatively little about its subsurface structures and preservation status.

 

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One half of the posthole exposed at Hovland Foto: Petra Schneidhofer

 

With permission from the Norwegian Directorate for Cultural Heritage, we excavated a section of one of the postholes, which revealed backfill consisting of multiple layers and large rounded stones. We were able to recover two charcoal samples, which are currently on their way to the laboratory for radiocarbon dating. Once the section was exposed, we installed five soil moisture sensors - three targeting the main backfill layers of the posthole and two of them just outside of it to capture the contrast between archaeological structure and its surrounding subsurface material. We spend considerable time to rodent-proof the cables connecting the buried sensors to the data hub using sturdy water hoses and tons of duct tape to make it as difficult as possible for the little critters to kill our sensors and thus sabotage the project. We also installed a rain gauge to accurately measure the precipitation at the site.

 

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Christer mounts the rain gauge at Hovland. Foto: Petra Schneidhofer

 

The installation went relatively smooth, but was interrupted by a series of heavy rain showers; not the best conditions for setting up electronics and also somewhat ironic given the fact that we were installing moisture sensors – but this is Norway and partly why we are doing this project.

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We test the sensors before we start backfilling the trench. Foto: Petra Schneidhofer

The set-up of Hovland’s station took us several days from starting to shovel until we could see the first data come in on our PC’s back at the office. Luckily, the three remaining stations at Lunde, Heimdal and Odberg proved a little less time-consuming, not least because we got help from Knut Paasche, head of department at our partners NIKU, who enjoyed a day in the field with us at Heimdal. A special thanks goes to reference group member Steinar Kristensen and his colleague Magne Samdal from KHM who visited us in Odberg, provided us with drone pictures and helped us out with a much needed extra role of the one and only duct tape.

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Knut Paasche came out to Heimdal for a sunny field day. Foto: Petra Schneidhofer

 

Publisert:

30.11.2020

Oppdatert:

08.12.2020 kl.16.26


Emneord:

Geofysikk