Abstract Manager

In November 2021, an atmospheric river brought an unprecedented amount of rain resulting in a series of devastating floods and landslides that severed several of BC’s major highway routes. A provincial state of emergency was declared.

As part of the province’s efforts to restore vital rail and road connections, the Ministry retained McElhanney to prepare a Corridor Traffic Management Plan (TMP) along a 36 km stretch of Highway 1 through the Fraser Canyon.

The subject corridor is mostly an undivided two-lane facility with a posted speed limit of 80-100km/hr, large proportion of heavy trucks, and curvilinear alignment with numerous curve speed advisories, with a river on one side, and rock on the other.

Below is an overview of the most critical sites with challenging mountainous terrain, potential rockfall and avalanche zones, and other unique challenges and constraints:

1. Jackass Mountain – a large section of road and a culvert were wiped out in a landslide here. A temporary single lane bridge structure was installed. Due to steep grades and geohazards, locations for safe staging of traffic were identified 6 km apart; hence the project included a 6 km single lane alternating traffic (SLAT) segment. The long SLAT segment with mid-block accesses required pilot vehicles, custom signage, and extensive public communication. The temporary bridge had a load restriction; could only manage one truck on the bridge at a time, and so innovative solutions were needed to ensure safe passage of traffic and workers safety.
2. Tank Hill - complete washout of a stretch of the highway at the Tank Hill underpass destroyed existing road and Canadian Pacific Kansas City rail infrastructure. An interim at-grade railroad crossing was implemented. A new temporary traffic signals with rail pre-emption were also employed so traffic could be safely stopped at the top of the hill during train crossing events.
3. Nicomen Bridge – erosion of the riverbank undermined the footings of the pier causing the bridge structure to settle. A detour with a temporary single lane bridge was implemented to restore traffic flow.

The Ministry and McElhanney worked collaboratively with multiple contractors on site, local communities, WorkSafe BC, trucking association, Drive BC, etc. and expedited the development and preparation of innovative TMP strategies to help safely reopen Highway 1 to the public under detour conditions within two months, in January 2022. Movement of people and goods and connection of communities were restored.