4 Results
4.1 Active Headwall Analysis
4.1.1 Headwall Properties s and Retreat Rate Variations
The average HWR rate increased from 12.5 m from 2016 to 2017, to 13.9 m from 2017 to 2018, with an average of 13.2 m from 2016 to 2018. The east and middle sections (Figure 4) experienced HWR rates of 7.3 m and 11.4 m respectively between 2016 and 2017, reducing to 3.3 m and 9.9 m respectively for 2017 to 2018. In contrast, the west recorded a mean HWR of 16.7 m for 2016 to 2017, increasing to 23.8 m for the 2017 to 2018 period. The HWR rates over the two years along individual transects ranged from 1.6 m a-1 to 41.9 m a-1. Changes in the headwall properties followed a similar pattern to the HWR rates. The IT and PI values decreased overall in the east and middle segments, while increasing in the west. The opposite is true of OT, which increased in the east and middle, and decreased in the west (Table 1).
Table 1:Overall stats in terms of Headwall Retreat (HWR), Ice Thickness (IT) Overburden Thickness (OT) and Proportion of Ice (PI) in headwall exposures on Peninsula Point in 2016, 2017 and 2018. HWR values are for 2016-2017 (2017), 2017 to 2018 (2018) and the 2016-2018 m (note that HWR rates are not available for 2016 as it was the first year of measurement)