BC Hydro update #5: Fraser River Transmission Infrastructure
3 p.m. PDT; Wednesday, July 6
VANCOUVER – BC Hydro is making steady progress in ensuring the stability of transmission towers and repairing damage caused by the fall of a 230-kilovolt transmission tower in the Fraser River in Surrey on Monday night, with public and employee safety and reliability remaining key priorities.
Immediate priorities:
- Monitoring the potential impact of high water flows on the 500-kilovolt transmission line and further stabilizing the two towers holding the line on both sides of the Fraser River.
- Reconstruction of the foundation of the south side 500-kilovolt transmission tower.
- Developing a plan to reconstruct the 230-kilovolt circuit.
Stabilizing, monitoring and repairs on the Fraser River
500-kilovolt tower – south side
- BC Hydro is monitoring the foundation of the 500-kilovolt tower on the south side of the river with specialized equipment around-the-clock. Surveying crews are continuing to conduct level surveys on the foundation multiple times a day using laser technology and are also continuing with daily underwater marine surveys to measure the level of the river bed. Crews have not observed additional erosion since Monday.
- Today, BC Hydro crews are installing guy wires on the transmission tower on the south side of the river, as a precautionary measure, by attaching cables to the top of the tower and securing them to the ground to create extra tension and stability.
- Crews are also re-positioning two existing guy wires on the south tower to improve stability.
- BC Hydro is continuing its plan of reinforcing the 500-kilovolt transmission tower with riprap (loose boulders) to increase stability and prevent further erosion. A barge shipment of riprap is expected later today to be placed Thursday along the riverbed and bank closest to the foundation of the tower.
- External specialists, including hydrologists and engineers are engaged to help monitor the situation and provide additional expertise.
500-kilovolt tower – north side
- Yesterday, crews installed two guy wires (support wires) on the tower on the north side of the river as a precautionary measure. This activity further enhances safety and prevents potential disruption to the public should the tower on the south side fall.
230-kilovolt tower (fallen tower)
- BC Hydro crews are building a detailed plan to remove the nearly 60-year-old fallen tower from the Fraser River. The tower is not impeding marine traffic or affecting the operations of other businesses or industry. The transmission lines that were attached to the fallen tower were removed from the river on Tuesday afternoon.
Monitoring of transmission towers
- In addition to regular hazard monitoring, BC Hydro has initiated immediate re-inspections of other transmission towers throughout the province that are built in or near rivers that have higher than normal water volumes this summer. No problems or issues have been identified at these sites to date.
- There are 47 transmission crossings across the full-length of the Fraser River, with six crossings on the lower mainland and through the Fraser Valley. All of these six crossings have been re-inspected and are all structurally sound. Only two of the six towers have footings in the Fraser River.
Power restoration complete
- Power was restored to nearly all of the 25,000 affected customers within 45 minutes, however a small group of about 30 customers remained without power on Tuesday afternoon. Power was restored to all of those customers on Tuesday evening.
Public Report on Tower Fall
- BC Hydro is commencing a full review of the incident and will report its findings publicly to the British Columbia Utilities Commission within 30 days.
For more information:
BC Hydro Media Relations
p. 604.928.6468