Colliery Dams: many unanswered questions

Colliery Dams was on the agenda at the Monday July 6, 2015 special council meeting. There were seven speakers.

The following is the presentation made by Geraldine Collins to Nanaimo council on Monday night.  She raised many questions that still have not been answered despite millions spent on studies.

We don’t know the following (about the Colliery Dams):

  • Spillway capacity – let us see the numbers
  • Water Distribution – where does the water go?
  • Auxiliary Spillway – without the studies we do not know what we need
  • Can the concrete wall survive the design flood?
  • Is the concrete strong enough?
  • What are the dimensions and geometry of the concrete wall?
  • Will the concrete fracture or erode?

If the concrete wall will not survive:

Do we need more rock to support it?
How much water will flow over the dam in the flood according to the model?
What is the lateral dissipation of the water once the spillway has reached capacity?

We can then then determine what upgrades we need.

Do we support the dam wall?
Do we protect from overtopping?
Do we redirect the water?

What happens to Nanaimo in a hypothetical 34,000 year flood?

Happens over time-days
Evacuation occurs downstream before dams crests
Flood damage throughout Nanaimo has occurred
Possible dam failure damage is incremental to widespread existing flood damage

City maintains that risk remains severe from a 34,000 year flood event
Risk Assessment is ignored
We do not know what will happen; pure speculation

We have spent $3 million and we still do not know:

  • The dimensions of the lower dam
  • Is the concrete strong enough to resist erosion?
  • Will it fail if overtopped?
  • The technical information regarding spillway capacity
  • Spillway measurements over high rainfall season
  • Dam dimensions and make up of concrete and rock buttressing

There is absolutely no urgency:

  • Insufficient data on record to support proposed option
  • Water level has never exceeded half of measuring board
  • Important to maintain realistic surveillance and emergency planning
  • Compile data for best solution

The Dam Safety Section has a history of accepting flawed studies:
“Time to do it right. Defy this order and stand up for what is right.”

There was another presentation by Louise Gilfoy which quoted the Nanaimo Mayor stating:
“While there’s 40 people perhaps that are actively involved in the Colliery Dam issue,
88,000 people live in Nanaimo” (June 29th quote from Nanaimo New Bulletin).

How many people are interested in the Colliery Dams issue? All taxpayers are interested in the Colliery Dams issue. Especially when it was first proposed and was going to cost  $30 million.

Presently, Nanaimo Council is split. Four say we must do as we are told and fix the dams immediately. Five say we must listen to the concerns of the taxpayers and get answers.

Highlights from the council meeting:

Councillor Kipp: “this whole process is so flawed…I am tired of all these threats…we still haven’t done any studies on what will happen downstream…the affidavits to DSS are false (and we know it).

Councillor Bestwick: “…people can sue me, I’ve got nothing in my name anymore…”

Councillor Pratt: “we can’t just do nothing…I agree with Councillor Thorpe…”

Councillor Yoachim: “doing nothing was never stated…” (everyone wants a solution).

Councillor Thorpe: “I know many people think I don’t care but I do…time has run out…I have listened to [the experts]…”

Councillor Brennan: “…they’ve given us a deadline…”

Councillor Fuller: “I will chain myself to a tree…stop laughing at me [to Brennan]…we don’t have any overtopping studies…”

Councillor Yoachim: “can we relax the hazard levels?…” (Golder Engineer replies yes)…

Swabey: “Golder likely doesn’t know what we are talking about…”

Counciller Hong: “how much snow and rain is required to fill the dams…”

Mayor McKay: heavy sigh… [time for new strategies]

Colliery Dams group has a new website.

Many people concerned about Colliery Dams
More than 40 people are concerned about Colliery Dams (photo from presentation to council by Louise Gilfoy)