Unmanned Aircraft System-derived terrain information J. van der - PowerPoint PPT Presentation

Permafrost dynamics and infrastructure impacts revealed by Unmanned Aircraft System-derived terrain information J. van der Sluijs *, R. H. Fraser, S. Kokelj, J. Tunnicliffe, I. Olthof NWT Centre for Geomatics, Canada Centre for Mapping and Earth Observation, NWT Geological Survey, University of Auckland

Introduction Challenges Intensification of climate-driven • thermokarst Thaw-related infrastructure problems • Information gaps Understanding magnitudes of landscape • change Kokelj et al. (2015). Global and Planetary Change Need to bridge spatial/temporal gap • through flexible solution (1 ha to 1 km 2 ) Unmanned Aircraft System (UAS) Reveal information about processes • previously difficult or impossible to study: – Retrogressive thaw slumps – Quarry/borrow pits in permafrost – Injection ice along roads

GENERAL APPROACH: EQUIPMENT, DATA ACQUISITION, DATA PROCESSING Flight planning Bradatech - RX4-S Surveyor w. 20 MP Sony RX100 III Bradatech - Sky Hero PX8 Plus 1000 Octocopter with Sony A6000 DJI - Inspire Pro, Phantom 4 Pro, Phantom 3 Advanced, Phantom 2 Sensefly - eBee Plus RTK/PPK Structure-from-Motion Photogrammetry (Pix4D) into 3D pointclouds (+DSM, ortho) Acquisition of overlapping photos 3

UAS Monitoring of Retrogressive Thaw Slumps (Behaviour in space & time) Fill Debris Tongue Slumps Failure precursor Embankment Failure 2015 2016

UAS Monitoring of Retrogressive Thaw Slumps and Creep Behavior of Roadside Fill Daily repeat surveys Annual repeat surveys 0-20 cm movements 0-45 cm movements Slump: rapid daily movement due to Engineered slope: slope and saturation relatively stable yet continued annual creep * CosiCorr Image Correlation Change Detection (Leprince 2007 IEEE Trans. Geosci. Remote Sens )

UAS Monitoring of Retrogressive Thaw Slumps (Dynamics & volumes of earth flows) A B C D

UAS Monitoring of Retrogressive Thaw Slumps (Failure modes, morphological processes & geotechnical properties) Ice-face at the headwall Semi-stable headwall Drainage capture Saturated fine- grained tills, Undisturbed Quickly warming Ice-face riparian at the drainage headwall Peat Headwall retreat is concentrated • deposit in areas indicated by colder temperatures Drainage tracks Saturated materials warm quickly • New phenomenon: slump retreat of drainage areas; influencing trajectory of change •

UAS Monitoring of Quarry/Borrow Pit Stability Challenges Active thaw slump, flow slide Slope instabilities 2016 UAS to monitor compliance, change trajectories; inform mitigation and best practices 2017

UAS Monitoring of Injection Ice (Dempster Highway) Frost front 2016 2017 Permafrost table * Ground ice formed during active-layer freezeback, where confining aquifer is developed between permafrost table and downward frost front Inuvik-to-Tuktoyaktuk Hwy

Annual change (July 2016 & July 2017) Elevation Active Layer thickness

Conclusion UAS provide a flexible means for visualizing permafrost dynamics and • infrastructure impacts Strong potential of UAS time-series analyses to study thermal, • vegetative, hydrologic, and geomorphic processes and feedbacks

Acknowledgements Department of Environment and Natural Resources – • Cumulative Impact Monitoring Program Natural Resources Canada - Polar Continental Shelf Program • • Tetlit Gwich’in (logistical support, assistance) Inuvialuit Land Administration • Department of Infrastructure • Department of Lands •