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Big Bar landslide response information bulletin

February 22 2021

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-40 C and chilly

Temperatures were cold but a successful ‘trim blast’ stirred things up at Big Bar this week. On February 13, the team was smiling after a successful blast of the canyon wall to straighten the future path of the permanent fishway. On February 14, crews also completed additional blasting of the Razorback and began excavating various grades of rock required for construction.

Other work included finalizing the grade of the embankment on which the structure will be built.

Winter conditions at Big Bar

Temperatures at site reached -40 C with heavy snowfall and freezing rain causing periodic shutdowns. These interruptions have affected the timeline for some of the cliff stabilization work and the upcoming pile driving for the north end of the fishway. To make up time, the prime contractor, Peter Kiewit Sons ULC, has added double shifts in some areas.

Water levels vary considerably in the Fraser River throughout the year. However, the levels have consistently dropped since December and crews have been able to access the river bed and perform in-river work necessary to build the fishway. The brief, critical window between December and April allow crews to finish the winter work before the snow melts and freshet occurs again. Operations will then shift to assisted transport of the early migrating fish that will be blocked by the slide.

Commencing and continuing construction on the permanent fishway during the winter low water remains essential to improving the survival of early migrating salmon stocks.

Roadwork contract awarded to Prime Quality Construction

On January 21, the BC Ministry of Forests, Lands, Natural Resource Operations and Rural Development (FLNR) awarded a road upgrade contract to Prime Quality Construction Inc. (PQC) following a competitive bid. PQC is an Indigenous owned company operated by a member of the High Bar First Nation.

In the coming months, based on a FLNR design, PQC will widen and realign the Chinook Main road that connects Beach One to the French Bar Creek area (see map). The improved road will be safer for crews and allow trucks carrying custom 17,000-litre fish tanks to pass during the critical fish “trap and transport” operations. PQC will also install radio communications towers at regular intervals along the road so truck drivers can coordinate during fish transport operations.

Rock sorting is underway here and this material will then be used on the road to French Bar Creek to re-slope cut banks, widen the road and create pullout areas for work trucks. In some areas, vertical walls made from soil, fabric and wire frames, also known as Geosynthetic Reinforced Soil Walls (GRS), will be used to support the road instead of the rock fill. The GRS will provide additional stability by containing the material below the road as their vertical orientation uses space more efficiently than rock fills, which need to be sloped.

Current images of work being done at the landslide site

Cold temperatures have resulted in significant ice buildup in the Fraser River, including just south of the Big Bar landslide.
Cold temperatures have resulted in significant ice buildup in the Fraser River, including just south of the Big Bar landslide. Click to enlarge.
Road grade work on the East Razorback, where crews have been quarrying rip rap.
Road grade work on the East Razorback, where crews have been quarrying rip rap. Click to enlarge.
The rock face, after blasting occurred to remove rock from along the path of the permanent fishway for a straighter alignment.
The rock face, after blasting occurred to remove rock from along the path of the permanent fishway for a straighter alignment. Click to enlarge.
Water levels were exceptionally high, 6,640 m3/s at Big Bar on July 6, 2020.
Water levels were exceptionally high, 6,640 m3/s at Big Bar on July 6, 2020. (Photo: Northwest Hydraulic Consultants) Click to enlarge.
Moderate water levels at Big Bar, 3,750 m3/s at Big Bar on May 6, 2020.
Moderate water levels at Big Bar, 3,750 m3/s at Big Bar on May 6, 2020. (Photo: Northwest Hydraulic Consultants) Click to enlarge.
On Feb 16, 2021, water levels were 620 m3/s, facilitating winter works.
On Feb 16, 2021, water levels were 620 m3/s, facilitating winter works. (Photo: Northwest Hydraulic Consultants) Click to enlarge.
The pile installation rig being set-up on the West Beach will be used to drive piles necessary to support the fishway.
The pile installation rig being set-up on the West Beach will be used to drive piles necessary to support the fishway. Click to enlarge.

Additional images of the work underway as part of our response efforts can be seen on the Government of BC’s Flickr channel.

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