News Release

12:00 p.m. PDT – Thursday, July 7

VANCOUVER – As BC Hydro enters day three of 24-hour operations for the repair and stabilization of the transmission lines across the Fraser River near the Port Mann bridge, crews will focus on the following actions while maintaining public and employee safety and power reliability:

Immediate priorities:

• Stabilizing the 500-kilovolt towers
• Finalizing plans to remove the fallen 230-kilovolt tower from the Fraser River under challenging flow conditions
• Continued monitoring and assessment

Stabilizing the 500-kilovolt towers

This morning, crews will begin laying nearly 900 cubic metres of riprap – approximately 18 truckloads of boulders and rocks – along the riverbed and bank closest to the foundation of the 500-kilovolt transmission tower on the south side of the river to increase stability and prevent further erosion.

After the riprap has been installed and further erosion is prevented, crews will drive steel piles into the bed of the Fraser River that will surround the tower and provide extra support and stability.

On Wednesday, July 6, BC Hydro successfully installed additional guy wiring (support wiring) on the 500-kilovolt tower on the south side of the river, as a precautionary measure, and repositioned existing wiring to enhance stability.

Earlier in the week, crews installed guy wiring as a precautionary measure to the 500-kilovolt tower on the north side of the river. This was done to further enhance safety and prevent potential disruption to the public should the tower on the south side fall.

The 500-kilovolt transmission line was initially de-energized on June 30 and will remain out of service while work continues with no interruption of service to customers.

Planning for removal and rebuilding of the 230-kilovolt tower (fallen tower)

Today, experts continue to finalize plans for the removal of the fallen tower from the river, taking into consideration the changing water levels and the extremely fast tidal flow of the Fraser River. Before removal can begin crews need to ensure the 500-kilovolt tower on the south side is stable. The tower will remain anchored underwater and marked with a safety buoy. Underwater dive inspections will be done to assess the most practical and safe way to remove the tower, which will likely involve using a barge and a crane. The tower measures 90,700 kilograms in weight and 83 metres in length – the equivalent of a 20-storey building.

BC Hydro experts have also started looking at design options for the rebuild of the span crossing the Fraser River and the rebuild of the three smaller wooden H-frame structures that were brought down with the fall of the tower.

Public reporting

Today, BC Hydro filed an initial incident report outlining the events of the past several days, with the British Columbia Utilities Commission and will file a full review with the Commission within 30 days.

Daily monitoring and assessment and standard monitoring procedures

BC Hydro continues to monitor the stability of the 500-kilovolt towers 24-hours a day. Experts are also continuing with daily surveying using laser technology and have not detected any movement in the towers over the past 48 hours. In addition, underwater surveying using bathymetric tools – specialized mapping equipment that uses acoustic signals – has shown no changes to the foundation of the river bed. 

BC Hydro is also continuing with inspections of all the transmission towers in the province that cross rivers that are experiencing high flows this summer. This includes 47 transmission towers facilitating the crossing of lines across the Fraser River. The six crossings on the lower mainland and through the Fraser Valley have all been re-inspected and deemed structurally sound. Only two of the six towers have footings in the Fraser River.

BC Hydro uses a variety of inspection techniques to assess the integrity of transmission structures. Structures are inspected regularly and guidelines are used to identify the type of inspection required and frequency. In addition, each year a risk assessment is done on anticipated flow conditions during the high flow season and individualized inspections and actions are undertaken to mitigate as necessary. This year’s risk assessment did not warrant actions beyond the scheduled inspections.

A 2010 report published by the Centre of Energy Advancement through Technological Innovation International surveyed many utilities across the world and it verified BC Hydro’s inspection standards as industry leading. BC Hydro standards are rated as “best practices” compared to other Canadian utilities and in most cases better than utilities in the US. BC Hydro’s standards also benchmark well against Australian, New Zealand and European utilities.

The fallen 230-kilovolt transmission tower was inspected according to BC Hydro standards. Four key types of inspections were performed on the 230-kilovolt circuit:

• Overview inspection – performed three times a year. Involves a general visual inspection of the transmission circuit and right-of-way corridor completed by a trained professional via helicopter or vehicle. The inspection is performed by a specially-trained power line technician who finds and records obvious defects that may affect the safe and reliable operation of the transmission circuit. The focus is on conspicuous defects, right-of-way encroachments and natural hazard reviews. The technician uses high-powered binoculars, laser range finders, cameras and other tools for the inspection.

• Detailed inspection – performed in 2010. This on-the-ground inspection includes, but is not limited to, performing a condition assessment of each individual structure with a focus on the structure itself, the insulators, conductor and associated hardware and components and civil works. The inspector, a specially-trained power line technician, is suitably equipped with high-powered binoculars, laser range finders, and other tools in order to assess the upper (pole top) elements of each structure. The inspector assesses and records the condition of the critical overhead components at each structure.

•  Hazard review or specific inspection – performed in 2010. This inspection is completed by trained and certified geotechnical engineers. This extensive inspection allows the engineer to compare the natural hazards (hillside movement, river erosion, etc.) from previous inspections to current conditions. These inspections are scheduled based on BC Hydro’s historical knowledge of the hazards, expert opinion, in-year occurrences of natural situations and information from other agencies, ministries and private companies (i.e. railways or other utilities). This inspection is usually performed every six years.

• Climbing inspection – performed in 2003. This type of inspection is intended to augment the detailed inspection and provide the inspector an opportunity to view critical components up close and with the naked eye and with suitable live-line tools. This inspection is used to assess the condition of each individual structure, insulators, conductor and associated components. It is generally conducted every 10 years.

 For more information:

BC Hydro Media Relations

p. 604.928.6468