Tuk Adaptation

  • Baird Erosion Mitigation

    At the April 11, 2022 Community meeting, Baird presented their design for erosion mitigation on Tuk Island and the coast of town. The animation of the design can be found by clicking the link below.

    Animation

Since the 1970s, a variety of strategies to slow erosion on Tuktoyaktuk's west shore have been tested, to limited success. Many reports have been produced over the years concerning past shoreline protection strategies and the recommended next step.

Below is a timeline of the actions that have been taken.

Featured
1972: Department of Public Works assessment
1972: Department of Public Works assessment

Upon request from the Government of the Northwest Territories, the federal Department of Public Works (DPW) [6] conducted a borehole campaign and erosion assessment for Tuktoyaktuk, specifically to advise on shoreline protection for the school. The primary mechanism of erosion was identified as thaw subsidence, and that any shoreline protection strategy should address ground ice thaw.

Photo of shoreline with longard tubes.
1976 – 1981: Longard tubes

Sand-filled synthetic fibre tubes installed in front of the old school to protect the shore and slow longshore transport. They were weakened by vandalism and waves, and eventually destroyed in 1981 [3].

1986: Aveco report – Shoreline erosion protection, Tuktoyaktuk

To determine the most effective shoreline protection strategies, Aveco Infrastructure Consultants [3] first assessed the relative contributions of longshore transport, offshore transport, and thermal action to total erosion on Tuktoyaktuk’s shoreline.

They concluded that further use of groynes (longshore interception structures) would have little effect. Beach nourishment was recommended as a relatively low-cost method of insulating the permafrost to mitigate thaw and protect the shoreline. [3]

1987 – 1993: Beach nourishment

Beach nourishment replaces eroded sand and gravel on the beach, providing a limited buffer by "feeding the ocean" and preventing erosion from the natural slope [8]. The beach nourishment was reported as having failed in 1993.

Photo of shoreline with sandbags.
1986 – 1997: Sandbags

Sandbags were placed behind the cemetery to protect the beach nourishment area, and provided their own slow-leak beach nourishment as they broke open. In 1997, following years of minimal maintenance, a severe storm removed the sandbags from half of their original shoreline extent when waves washed over the sandbags and eroded the shore from behind [9].

1994: UMA report – Tuktoyaktuk Shoreline Protection Study

UMA [8] adopted the annual average shoreline change reported by Public Works, 1.8 meters per year, as a conservative estimate of erosion in unprotected sections, and concluded that without action the peninsula would lose road access by the year 2040.

Several possible solutions were proposed, including the least-cost option of gradual relocation of buildings and cultural sites off the peninsula, or a phased approach of protecting vulnerable test sections first. The community opted not to relocate, and instead to continue reinforcing the shoreline.

At that time, the community identified priority areas for protection (in order of most to least importance): the cemetery, residential housing, the school, industrial buildings, and commercial buildings.

Photo of man on shoreline with tilted concrete footings and sandbags.
1996 – 1997: Concrete footings

Concrete blocks measuring 1 m x 1 m x 0.25 m were placed on the shore behind the cemetery, along with the sandbags. They were undermined the following year by storms [4,10].

Photo of large riprap on the point.
1996 – present: Quarry stone / riprap

Graded quarry stone was placed on the coast in 1996 and 1997, although was damaged in the same year due to insufficient size and quantity for the wave exposure [4, 11]. More riprap has sporadically been added to over the years. The riprap currently in place varies in size and in some sections has been displaced from its original location [4].

1997: Trillium report - Tuktoyaktuk erosion control using monolithic concrete slabs

In preparation to install monolithic concrete slabs which had been offered to the community [9], Trillium Engineering and Hydrographics Inc. [11] suggested a design to install the slabs that would protect the underlying permafrost from thawing and shifting, and would prevent undermining the structure. They also examined the existing riprap protection, and suggested reconstruction of shoreline protection in sectors where the sandbags had been washed away.

Photo of shoreline showing concrete slabs.
1998 – present: Monolithic concrete slabs

Concrete slabs measuring 2.5 m x 10 m x 0.5 m were installed along approximately 100 meters beginning at Flagpole Point, along with a rip rap apron and splash pad [11]. The slabs continue to be effective, although Trillium reported that they would likely be overtopped during a 100-year storm event [6,11].

To date, erosion continues to create challenges for the community. Erosion mitigation efforts are one part of an adaptation pathway, providing the community with time to decide what the next step in the adaptation process will be.

References

[1]Aré. 1988. Thermal abrasion of sea coasts. Polar Geography and Geology, 12, p.1-157.

[2]Wolfe et al. 1998. Coastal permafrost investigations along a rapidly eroding shoreline, Tuktoyaktuk, N.W.T. In: Lewkowicz & Allard (eds.) Proceedings of the 7th International Conference on Permafrost, p. 1125-1131.

[3]Aveco. 1986. Shoreline erosion protection Tuktoyaktuk. Report for the Government of the Northwest Territories, Public Works and Highways.

[4] Tarin Resource Services. 2010. Aerial imagery of Tuktoyaktuk and surrounding areas.

[5] USGS / USGov. 2006. Longshore. https://commons.wikimedia.org/wiki/File:Longshore_i18n.png

[6] Baird. 2019. Tuktoyaktuk Coastal Erosion Study. Report for the Government of the Northwest Territories, Municipal and Community Affairs.

[7] Public Works Canada. 1976. Shore erosion and protection study, Tuktoyaktuk, Stage 2 Report Volume 1. Report for the Government of the Northwest Territories.

[8] UMA Engineering Ltd. 1994. Tuktoyaktuk shoreline protection studies, phases ii and iii, interim report no. 2. Report for the Government of the Northwest Territories, Department of Municipal and Community Affairs.

[9] Solomon & Covill. 1995. Impacts of the September 1993 storm of the Beaufort Sea. In: Proceedings of the 1995 Canadian Coastal Conference, Vol. 2

[10] Solomon. 2001. Tuktoyaktuk risk assessment 2001. Appendix A of Hamlet of Tuktoyaktuk Shoreline Erosion Progression and Community Impact Study (UMA 2002).

[11] Trillium Engineering and Hydrographics Inc. 1997. Tuktoyaktuk erosion control using monolithic concrete slabs. Prepared for Hamlet of Tuktoyaktuk.

[12] Baird. 2021. Tuktoyaktuk Erosion Mitigation. Report for the Hamlet of Tuktoyaktuk and the Inuvialuit Regional Corporation.

[13] Barnhart et al. 2014. The effect of changing sea ice on physical vulnerability of Arctic coasts. The Cryosphere, 9. doi: 10.5194/tc-8-1777-2014

[14] Dallimore et al. 1996. Deep-seated creep of massive ground ice, Tuktoyaktuk, NWT, Canada. Permafrost and Periglacial Processes, 7, pp. 337-347.

[15] Héquette & Barnes. 1990. Coastal retreat and shoreface profile variations in the Canadian Beaufort Sea. Marine Geology. 91. doi: 10.1016/0025-3227(90)90136-8

[16] Thomson & Rogers. 2014. Swell and sea in the emerging Arctic Ocean. Geophysical Research Letters. doi: 10.1002/2014GL059983