Top News

RUSSELL WANGERSKY: No runaround, just dam statistics

Barnard-Penecon JV, Ltd. was the successful bidder in a tender to construct the north and south dams at the Muskrat Falls site. They won the contract over two other bidders, including Astaldi Canada, the contractor currently responsible for the construction of the powerhouse and spillway on site.
Muskrat Falls hydroelectricity dam construction site. — SaltWire Network file photo

I apologize in advance if this column is like inside baseball — that is, mostly about the business of news, rather than news itself.

But part of this story so impressed me that I thought I should point it out.

Two weeks ago, I was looking at plan filed by Nova Scotia Power at the Nova Scotia Utility and Review Board.

The topic? The power company there wants to refurbish one of its hydroelectric dams, the Tusket Main Dam, built in 1929. The repair will cost over $18 million and is needed to bring the facility up to Canadian Dam Association dam safety guidelines — not only that, the new dam is being designed and built to meet any concerns from a 1:1000 year flooding event. In other words, the thousand-year flood.

And I wondered about dams in this province, particularly those run by our biggest power producing provincial utility, Newfoundland and Labrador Hydro. Do they meet the 1:1000 standard? Do they even have to?

(This in itself is an interesting part of journalism: there are hundreds of things every year that look like they might be stories, but they just don’t pan out. Contrary to popular opinion, most journalists don’t wander around saying “Let’s see who we can embarrass this week.” Many of us find things that interest us and search out more detail. Sometimes, it becomes a story, and sometimes the cake just will not bake.)

Now, anyone who’s in the media, or knows a lot about it, knows that the relationship between the media and communications staff can be fractious.

Now, anyone who’s in the media, or knows a lot about it, knows that the relationship between the media and communications staff can be fractious. We have different goals; the media looks for information, while communications staff want to present one side — their side — accurately but in the best light. Lately, there have been many cases where it seems like fencing; we ask one thing, and get a huffy response that doesn’t even answer the question.

But when I asked Hydro about dams, I received one of the best, most complete answers I have ever gotten.

“Hydro implements a dam safety management program, and as part of this program, we regularly carry out a number of measures focused on ensuring the ongoing safe, responsible operation and maintenance of our dams. … Hydro follows the Canadian Dam Association (CDA) guidelines, which are considered best industry practice in Canada. It is worth noting that the CDA guidelines provide recommendations and guidance on best industry practice to utilities in Canada, and are not considered requirements or standards.

“A 1:1000 flood, in more general terms, is a reference to one of many possible design floods. Each dam is designed to a specific design flood based on its hazard classification (also known as dam classification in the CDA guidelines). There are five dam classifications outlined in the CDA guidelines and each has a corresponding design flood to which the dam should be designed, as noted below.

Class                 Design Flood
Low                   1/100
Significant         between 1/100 and 1/1000
High                  1/3 between the 1/1000 and the Probable Maximum Flood (PMF)
Very High          2/3 between the 1/1000 and the PMF
Extreme            PMF

“There are approximately 94 Newfoundland and Labrador Hydro-owned dam structures in the province. Of the 94 dams, 89 meet all CDA criteria, and five dams (4 at Snook’s Arm, 1 at Roddickton) meet most of the CDA design criteria. (These five are all smaller structures (4 metres or less in height)). All structures are monitored and managed for safe operation in accordance with CDA guidelines for management, whether or not they currently meet all CDA design criteria. All of our dams are classified using the methodology outlined in the CDA guidelines. Currently, there are 34 dams with a Low dam class, 30 with Significant, 19 with High, 9 with Very High and 2 with Extreme.

“Regarding your question if Hydro’s dams meet the 1:1000 year design flood — as required by the CDA, all of our High, Very High and Extreme dam classification dams exceed the 1:1000 (year) design flood, with some of our Significant classification dams also exceeding the 1:1000 (year) design flood (i.e. exceeding the CDA recommendation).”

A great, clear answer — and proof that every single thing doesn’t have to be a battle.

Russell Wangersky can be reached at [email protected] — Twitter: @wangersky.


Recent columns by this author

Recent Stories