Colliery Dams Tech Committee public status update May 26
FOR IMMEDIATE RELEASE:
May 26 2014
RISK CLASSIFICATION OF COLLIERY DAMS REDUCED FOLLOWING PHASE ONE WORK OF TECHNICAL COMMITTEE
Work undertaken by Golder Associates on behalf of the Technical Committee during Phase One of its mandate included detailed site testing, analysis and risk assessment of the Colliery Dams. That technical analysis indicated that there is an extremely low risk of sudden or rapid failure of the dams in an earthquake that would cause a large wave of water or debris to impact the neighbourhood below the dams.
That work has been a significant factor contributing to the replacement of the “Extreme” consequence classification of the dams by lower classifications, as described in this public update.
Analysis is continuing to determine the best option to increase spillway capacity, which must be expanded to meet flow requirements in a prolonged heavy rainfall. A further report will be issued in approximately 4-6 weeks on the remediation work to be undertaken, the schedule, the status of signage in place, and the timing for release of the consultants’ reports.
Background:
- An update on the status of the Technical Committee’s work was last provided on March 24 2014.
This update provides information about the physical state of the dams that has emerged through Phase One of the work of the Committee.
- The mandate of the Committee is to focus on options for remediating the existing dams
that will satisfy the requirements of the BC Dam Safety Regulation, which is administered by Dam Safety Section (DSS) of the Ministry of Forests, Lands and Natural Resource Operations
- As part of Phase One of its work under that mandate, the Committee was tasked with reviewing existing data and collecting additional data with the objective, among other things, of “potentially reducing the hazard rating of the dams through better understanding of the dam structures, failure rates and methods/probability of events that would result in
failure of the dams.” (In the Regulation, the term used for “hazard rating” is “consequence classification.”)
Risk assessment approach:
- In its approach to the Phase One work, the Committee endorsed a “risk assessment” approach to assessing the physical state of the dams (engineers Golder Associates were selected by the Committee to undertake this work based on their high level of expertise in this area and their recommendation that a risk assessment approach be used to develop the most appropriate remediation options in due course).
- Why has the Committee taken this approach?
o Changes to the Canadian Dam Association Dam Safety Guidelines made in October 2013 provided the Technical Committee with the opportunity to employ this approach to evaluate the dams and their hazard rating (consequence classification), and develop the most appropriate remediation options to achieve acceptably low public safety risk.
The attached public information update is provided by the Colliery Dams Technical Committee. Inquiries may be directed to the Committee spokesperson, facilitator Katherine Gordon, at (250) 247-7285 or katherinegordon@shaw.ca.
