Let’s hear from a real expert

The Telegram
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I would like to comment on points raised in James McLeod’s interview with Gilbert Bennett of Nalcor in The Weekend Telegram, Aug. 23.

1. Rather, than talk about landslides downstream of Muskrat Dam being “no big deal,” I suggest it would have been more enlightening to note that the behaviour of alluvial rivers, such as the Lower Churchill, involves the continual evolution of their channels via erosion and deposition and that landslips along the banks are perfectly natural consequences of this process.

2. The presence of sensitive marine clays underlying the North Spur is a very serious problem. This material, when disturbed, can liquefy and cause massive landslides. One has only to recall the disaster at Saint Jean-Vianney, Que., in 1971 where 31 lives were lost. There have been many other incidents of this type, particularly in Quebec where sensitive marine clays are common.

On the question of the stabilization of the North Spur, the article cites engineer Regis Bouchard, who states that the North Spur stabilization design is unique but that solutions applying proven technology will fix the problem.

The Telegram article mentions building a “concrete and bromide” wall. I presume that “bromide” was a typographical error and that “bentonite” was intended. Given the challenges of stabilizing the North Spur/natural dam, I expect that Nalcor would have engaged world-class experts to advise them on this question.

The article notes that the  (unnamed) engineer engaged to provide project oversight has signed off on the proposed design. As a member of the public, I will not be satisfied that Nalcor has properly dealt with this problem until a real expert comes forward to discuss this issue in public. It is not good enough to get a second-hand opinion on such an important issue from Bennett, who is clearly not an expert on the subject, when presumably real experts are available.

3. A related issue concerns the risk of landslide generated water waves in the reservoir that could be produced by a major landslide into Muskrat Reservoir upstream of the dam. It would be interesting for the public to know how the dam design has been adapted to protect against this threat.

P.C. Helwig, consulting engineer

St. John’s

Geographic location: Quebec

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Recent comments

  • Too Funny
    September 05, 2014 - 16:17

    That's funny. Issue a call for real experts and you quickly hear from the... well, non-experts.

  • Here here
    September 05, 2014 - 14:35

    I agree. Lets here from the REAL experts. Not the self appointed ones flooding the Telegram with letters and comments.

    • Tony Rockel
      September 06, 2014 - 07:41

      Oh yes, as though you'd be able to recognize one!

    • Here here
      September 08, 2014 - 10:39

      I probably wouldn't recognize a real expert but it's easy to spot the self-appointed ones from miles away. They look like you. I doubt if you're an expert in anything other than posting moronic comments. Good luck with that. Cheers.

  • Anthony Rockel
    September 05, 2014 - 13:27

    So here we have a consulting engineer voicing, in part 3 of his letter, the same concerns I expressed in my letter of Sept 02. But of course the Nalcorholics will continue to bury their heads in the sand and blunder on until the truth is finally inescapable.

  • Cyril Rogers
    September 05, 2014 - 10:53

    Muskrat falls is a fiscal nightmare on the basis of its business case…..without the added threat of the dam giving away….and the loss of life that would likely ensue from such a collapse. The glib assurances of NALCOR notwithstanding, the North Spur is a potential catastrophe in the making , and only adds to the possible fiscal nightmare the people of the province will be forced to endure for decades. I profess to no engineering expertise…and they may very well engineer a solution that works…but at what cost? The "solution" has the potential to add exponentially to the overall cost of the project…yet, NALCOR continues to propagandize this untenable project, while the provincial government supports it for nefarious reasons.

  • J
    September 05, 2014 - 08:52

    I'm sure Nalcor would be lost without the letter writer and the anti-MF commentator from the comments performing backseat engineering.

    • Anthony Rockel
      September 05, 2014 - 09:27

      Nalcor was lost LONG ago.

    • Maurice E. Adams
      September 05, 2014 - 09:43

      To "J's" comment and the writer's point #3:------- If Nalcor has done such expert work, why not provide the public with the study that addresses the writer's 3rd issue.----- 1. upstream horizontal trust/water pressure on the reservoir's bank will increase exponentially with the expected 3-4 fold increase in the water depth, 2. the resulting distance between the 39 metre reservoir elevation and the downward slope leading to the approx. 28 metre elevation of the middle Kettle Lake/1000 metre long valley/gorge to the downstream 3 metre river elevation level, is less than the 600 metre distance between the upstream/downstream sides of the North Spur itself, 3. there are 2 (upper) quick clay layers beneath this shorter, high risk area, 4. with the higher elevation of the reservoir, both these quick clay layers will then be either totally or partially BELOW the reservoir level, 5. Nalcor's proposed North Spur design fix excludes this area, 6. Nalcor's proposed design fix will increase the water pressure in this area, 7. earlier stratigraphic interpretations described a layer below these upper clay layers as the more stable 'intermediate sand', while later interpretations now describe that layer as intermediate silty/sandy or sandy/silt (silt being the very next category adjacent to 'quick clay').-------- So, will the North Spur fix create an even higher risk by way of a possible breach through the Kettle Lakes area?

  • Maurice E. Adams
    September 05, 2014 - 06:30

    I think (but stand to be corrected if in error) that MCLeod's article said only that the 'independent' engineer had approved of the the "design APPROACH", not the design itself (and as I understand it, the design had not even been done at the time that the engineer approved of the "approach" ---- again, more incomplete and/or misleading information from Nalcor.