COLLIERY DAMS TECHNICAL COMMITTEE
Mandate of Technical Committee:
On October 21, 2013 the City of Nanaimo struck the Technical Committee with a mandate to focus
on outcomes that only involve remediating the existing dams, using the following phased approach:
• Phase 1: Review the existing data and direct additional data collection as necessary.
• Phase 2: Develop option(s) for remediating the existing dams that will satisfy the
requirements of the Dam Safety Section of the Ministry of Forests, Lands and Natural Resources.
• Develop plans for short-term physical alterations to the dams in 2014 to provide the
necessary time to carry out the long-term strategy (if required).
Composition of Technical Committee:
The Committee is comprised of representatives of the City; Snuneymuxw First Nation; the Colliery
Dams Park Preservation Society; and engineering firm Golder Associates. Committee facilitator
Katherine Gordon was appointed on November 26. Both Golder Associates and Gordon were
appointed by the Committee after review of a number of candidates.
Katherine Gordon will act as the contact person in relation to any questions about these updates or
the work of the Committee.
Role of Technical Committee:
The Committee is tasked with making viable recommendations on rehabilitation options to be
reviewed by the City, Snuneymuxw First Nation and the Dam Safety Section. Those
recommendations are to be made by February 28 2014 to the Executive Committee, which is
comprised of City senior staff and Snuneymuxw advisors directed by the Chief. The Executive
Committee oversees the Technical Committee and if necessary provides guidance and advice to the
In due course the Executive Committee will provide commentary and recommendations to the
Policy Group (Mayor and Council/Snuneymuxw Chief and Council) for consideration and discussion.
As owner of the dams, City Council must make the final decision on which rehabilitation option to
pursue and any short-term mitigation options required before permanent remediation takes place.
The parties involved at the table agree that this is a fair, credible process to follow.
Meetings of the Technical Committee
The Technical Committee has met twice, on December 5 and 13, and three meetings are scheduled
for January to discuss communications and risk assessment approaches and technical options being
developed by Golder Associates for committee consideration. Representatives of the Dam Safety
Section attend meetings in order to ensure they are fully informed and are able to contribute to the
progress of technical discussions.
Objective of the Technical Committee
The Committee has agreed on the following overarching objective for its work:
Development of an environmentally minimally invasive, cost- and time-effective solution while
satisfying required safety standards - i.e. a solution that addresses:
• The safety of downstream residents and workers;
• Dam Safety Section requirements;
• The respective objectives of the City, Snuneymuxw First Nation, the Colliery Dam Park
Preservation Society and the community;
• Environmental concerns, including fisheries habitat and ecology;
• Cost-effectiveness; and
• Having a timely permanent solution in place in 2014 if possible, but no later than 2015, with
shorter term mitigation in place if required in 2014.
Approach to Development of Rehabilitation Options
The Committee is combining work on Phases 1 and 2 of its assigned tasks. Golder Associates is in the
process of reviewing the existing data and collecting additional data as required. The Committee has
provided Golder with copies of historical and other relevant documents and reports and City staff are
working with Golder to provide whatever support is required in order to conduct any additional physical
site investigation of the Lower and Middle Dams.
The physical site investigation involves a limited geophysical examination of the two dams that will take
place during the week of January 13. This is a non-invasive way to survey a large area of the dams with
hand-held equipment that can be used in areas that are difficult to access with conventional drilling
equipment and minimize disturbance to the dams and watercourses.
The objectives include providing information related to the internal dam fill zoning of the two dams,
gathering information about the water table, underlying foundations and reinforcement (such as rebar)
within the concrete wall, collect information which may help to establish whether a low-level-outlet may
exist, and gather any other geophysical information, including seismic velocities, that will help in
developing suitable remediation options.
The work will be carried out on land, is non-invasive and is not expected to have adverse
environmental impacts as the radar and seismic signal sources are all very low energy. However, it
may be necessary, during one day of seismic surveying, to limit public access in order to minimize
vibration noise during the seismic recordings. If this is the case, notices will be posted at entrances
to the Colliery Dams Park and on the City of Nanaimo website, as well in local newspapers.
A second phase of site investigation will likely take place in the first half of February and involve
investigative drilling in the embankments and concrete core of the dams. The geophysics work may
provide information that will influence the scope of the drilling.
At the same time, Golder has adopted an approach which includes the revised (2013) Canadian Dam
Association Dam Safety Guidelines to satisfy Dam Safety Section requirements. This approach applies a
risk assessment methodology to the development of satisfactory rehabilitation options. Dam Safety
Section staff have indicated that they are willing to work with this new approach. It is an approach that
both governments and industry are increasingly moving towards in developing cost-effective strategies
to address risk issues.
Over the next few weeks, Golder will be undertaking a risk assessment of the dams and concurrently
developing technical remediation options. The preliminary work will be presented to the Committee in