This Dam is Your Dam, This Dam Is My Dam, Part 5: Courting Catastrophe at North Spur

"Nothing short of proof will suffice any longer. The choice is between the burden of proof and the burden of a potential catastrophe, and so the choice could not be clearer."

Right off the top let me just say, if this piece sounds alarmist, it’s because I’m alarmed. Sounds foolish several months into researching and writing about Muskrat Falls, but only because the project is an established disaster from so many different perspectives.

Still, digging into the North Spur has genuinely scared the hell out of me. And that’s about enough of my feelings, I agree; I’m obliged to attempt to communicate the facts here as clearly as possible. All the more so since this is a situation where technical complexity too easily obscures the elementary brutality of what the geotechnical analyses of several experts have come to predict: the very high risk of collapse of the North Spur when the reservoir is filled in late 2019, or upon sustained strain sometime thereafter.

The North Spur is a landmass that juts out into the Churchill River at Muskrat Falls, acting as a natural dam in tandem with the concrete dams constructed by Nalcor that gap the Falls themselves. The Spur is thus foundational to the design of the project.

Back in 2011, experts from the Geological Survey of Canada in testimony to the joint Federal-Provincial environmental panel appointed to review the viability of Muskrat Falls (whose concerns, as noted in previous segments of this series, government and Nalcor have largely ignored), documented the presence of glaciomarine clays in the Lower Churchill.

This did not escape the attention of the Grand River keeper and Labrador Land Protectors, who, as they wrote in their submission to Commissioner LeBlanc, “for years now … we have been consistent in our requests, letters, media and submissions that we were not convinced that Nalcor had done all that was possible to ensure the North Spur would hold.” Accordingly, these local groups, comprised of people whose homes and possibly lives depend on the stability of the North Spur, reached out to Dr. Stig Bernander, one of the world’s leading experts in glaciomarine clays, to investigate the risk assessment methods applied by Nalcor and their contracted engineers, SNC-Lavlin.

Dr. Bernander’s findings, dense with technical detail, are simple enough in their devastating implications. The crux of the issue is that the quick clay of which the North Spur is primarily composed liquefies under pressure, and Dr. Bernander has found that Naclor’s design approach substantially overestimates the strength of these sensitive soils. The geotechnical models developed by Bernander and his team indicate that “full reservoir impoundment at the normal operating level of +39m above sea level will surpass the strain limit [of these soils] by a factor of 3,” as summarized by PlanetNL. The Spur is in fact composed of several overlapping layers of glaciomarine soils, all of which are angled downstream; and so even if Nalcor’s estimates do correctly apply to some of these layers, it will only take one single layer to be weaker than estimated and liquify into a sliding plane on which all layers stacked above will totter to trigger an enormous downhill landslide.

[Note: if the reader would like this explained in extensive detail by professionals, I urge seeking out Bernander’s full reports and Jim Gordon’s “final comments on the North Spur.”]

How exactly have Nalcor and SNC-Lavlin made such pivotal underestimations? Dr. Bernander’s report raises several highly technical flaws in the design approach, one of the most prominent being that the Project Engineers have employed a modeling type that fails to capture dynamic strain effects that can transform the clay into a liquid. The soil characteristics as represented in Nalcor’s models, according to Bernander, do not reflect the likely behaviour of those actually present in the North Spur.

Nalcor responded at the end of 2017 with the convening of a Geotechnical Peer Review Panel (GPRP), whose resulting report defended Naclor’s methodologies and dismissed Dr. Bernander’s findings. But hydroelectric consultant and retired engineer Jim Gordon, upon review of this report, was not convinced: “I still question whether the North Spur is safe, based on the lack of data and absence of geotechnical analysis in the GPRP report to support their conclusions.”

But it gets darker still. Mr. Gordon continues, “It is unfortunate and unusual that the GPRP did not consult Dr. Bernander, or give him any opportunity to respond to their concerns. Also, it is unfortunate that none of the staff within the Nalcor organization have the experience to discuss and question the GPRP findings. Nevertheless, in view of the recent revelation that Nalcor edited reports by the “Independent Engineer,” this inexperience may not have prevented Nalcor staff from ‘marking-up’ or ‘vetting’ the report of the GPRP or setting parameters/mandates that the GPRP had to follow which would only give the answer sought by Nalcor.”

The baffling details just keep bubbling to the surface. Upon investigation I found that sure enough, thanks to the diligence of Des Sullivan (aka Uncle Gnarly) in filling an ANTIPPA request for information, “evidence has now been uncovered showing that the “independence” expected of the Independent Engineer for the Muskrat Falls project, on behalf of the Government of Canada, was never established; that at the very beginning Nalcor was permitted to review, edit and redact the Reports before they became public.”

Whether or not the GPRP’s report was subject to the same treatment, the fundamental, extremely worrisome fact is that according to a foremost authority on glaciomarine soils, the stability of the North Spur remains unproven. Nalcor’s belief that this natural dam will not break, then, is founded on the wild hope that Dr. Bernander has simply misjudged the characteristics of soils he has spent a distinguished career studying.

Once again, Nalcor insists we take them at their word that everything will be fine. I don’t have to tell you where it’s gotten us, to have repeatedly taken Nalcor and government at their word; but this time, if they’re wrong again, the consequences will be mass destruction, flooding, and potential drowning downstream, and the neglect will be historic and criminal.

The provincial government must be made to appoint, in Jim Gordon’s urging, “an eminent panel of geophysical experts, completely independent of Nalcor, to assess the scientific evidence and undertake all necessary additional research.”

Nothing short of proof will suffice any longer. The choice is between the burden of proof and the burden of a potential catastrophe, and so the choice could not be clearer.

Written By
More from Greg Hewlett

This Dam is Your Dam, This Dam is My Dam, Part 1: Unpacking Muskrat Falls

Writing about Muskrat Falls comes from the urge to keep track, bear...
Read More

3 Comments

  • Here’s a link to Dr. Bernander’s report:

    https://www.scribd.com/document/366056653/Summing-Up-of-North-Spur-Stability-Issues-by-Dr-Stig-Bernander

    Here are Jim Gordon’s “final thoughts on the North Spur” including his list of recommendations for government:

    https://unclegnarley.blogspot.com/2018/07/jim-gordons-final-comments-on-north-spur.html

    “Recommendations:
    The government of NL should appoint an eminent panel of geophysical experts, completely independent of Nalcor, to assess the scientific evidence and undertake all necessary additional research, and undertake a comprehensive review of the safety and stability of the North Spur. The Panel’s work should include:

    1. Giving Dr. Bernander and his associate Dr. Elfgren the opportunity to respond to the GPRP report, and include their comments therein.
    2. Assessing the results of stress-strain tests on the various soils within the Spur, to demonstrate that the linear relationship and softening factors have been correctly determined and applied to the geotechnical calculations.
    3. Producing a three-dimensional computer model of the strength of the various soil layers within the spur, to demonstrate that there are no extensive layers having a strength below average strength, which could form a sliding plane.
    4. Undertake a reliability analysis of the safety of the Spur.
    5. Seeking precedents for the use of CDA dam safety factors in slope safety calculations in a natural dam.”

  • If anyone the sign off that the Dam is SAFE and it FAILS. GO STRAIGHT TO JAIL. It’s not a board game they are playing with here.
    Is that the ACTUALLY pic of North Spur? If So NALCOR is spending a LOT of Extra $$$ to fix the problem with the North Spur. It was to be a natural embankment

    • I couldn’t agree more with you but if the dam doesn’t fail then all the people that cost us 10’s of millions of dollars protesting should have to pay back every cent.

Leave a Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.