Evaluating the Coastal Erosion and Climate Risks to Historical Antarctic Monuments

Golder, now a member of WSP, was engaged by the Trust to complete a geotechnical assessment of the area around Scott’s Discovery Hut (built in 1902) and Vince’s Cross (erected in 1904), which are important heritage structures located on Hut Point Peninsula, near McMurdo Station and Scott Base, Ross Island.

These physical testimonials to the Heroic Age of Antarctic exploration have previously been included on the World Monuments Watch list by the World Monuments Fund (WMF). Both historical structures are monitored by the Trust as part of an ongoing programme of care which tracks environmental factors and trends, and carries out preservation interventions as required.

The Trust monitors local geotechnical conditions including coastal erosion of adjacent slopes and fretting or shoreline erosion and local ground and building level surveys are performed regularly to assess any subtle changes in the local topography.

Our geotechnical assessment team visited the site in November 2019 to observe the geological setting and to identify any geomorphological evidence for instability or active erosional processes. We also carried out a ground-penetrating radar (GPR) survey around Discovery Hut to identify the extent and layering of ice and rock beneath the structure and calibrated the data against observations from our client’s previous excavations.

Vince’s Cross is situated a short distance from Discovery Hut, at the edge of Hut Point Peninsula looking out over McMurdo Sound. The bluff face adjacent to it has some areas which are erosion prone. Using a semi-quantitative risk assessment approach, we estimated the likelihood and consequence of a slope failure affecting Vince’s Cross in order of magnitude scales and combined these values as a risk score. The event could be expected to occur within an approximately one-hundred-year period under normal conditions but is unlikely to occur within the next few years, except under unusually adverse circumstances.

We recommended that the Trust consider potential mitigation strategies that could be implemented to reduce the coastal erosion risk to Vince’s Cross. Monitoring the slope is already in process and we recommended some technical options for refining this. Slope protection is technically possible but practically infeasible, so other recommendations centre around options for re-location, should monitoring detect an increased risk of erosion.

Our GPR survey at Discovery Hut confirmed an ice layer of up to one metre, underneath and between scoria, but deeper conditions remain unknown. Current monitoring shows hut levels are stable and have been so for many years. We recommended continuing to monitor the floor levels of the hut to identify any trends in movement that would indicate instability of the slope or foundations. We also recommended further subsurface investigation to confirm foundation conditions and installing thermistor strings to measure seasonal changes in ground temperature.
Due to our involvement, the Antarctic Heritage Trust now has greater insight into the current conditions of these heritage structures, the risks posed to the structures by local environmental change and coastal erosion, and a range of potential mitigation options to protect these important historical structures for future generations.

At the time of the project, work was contracted to Golder, which was later acquired by WSP