Guest Post by David Vardy
The North Spur Remains Unresolved and Urgent
Muskrat Falls is the only hydroelectric project in the world which relies on a large natural dam, underlain by sensitive glacial clays, and raising major concerns for local communities. Experts from the Geological Survey of Canada documented the extensive presence of glacial marine clays in the Lower Churchill in their testimony to the joint federal-provincial environmental panel.
The Labrador Land Protectors presented a petition to government on May 9, 2017 calling for the appointment of an independent expert panel on the North Spur. It was signed by more than 1000 people. There has been no response. Since that time the urgency of the panel has been raised. It has been raised by new research conducted in Sweden as well as by revelations flowing from the SNC risk assessment report released by the Premier.
The recently disclosed and disturbing SNC Lavalin risk assessment report of April 2013, released by the Premier on June 23, 2017, refers to the need for further geo-scientific information to guide remedial measures and assess overall safety and stability. SNC Lavalin rated the risk as “very high.” Whether Nalcor has successfully remediated these risks over the period from April 2013 to the present is as yet unknown. It will take the work of an independent expert panel to measure whether risks have been reduced or indeed whether they can be mitigated or eliminated.
On January 16, 2017 Ron Penney and I wrote the Chair of the Muskrat Falls Oversight Committee to call for urgent action on the North Spur. We had given up on Nalcor, having made strong representations in person and in writing for appointment of an independent review panel without success. Our letter was supported by a list of 20 major concerns with the safety of the North Spur, compiled by Jim Gordon along with Maurice Adams and other colleagues.
We approached the Oversight Committee out of desperation in our efforts to convince Nalcor that they should embrace our call for an independent review. On July 17, 2017, more than six months later, we received a response from Nalcor to the 20 questions, having been informed by the Oversight Committee that they had referred our concerns to Nalcor and asked them to respond. So much for independent oversight by the Oversight Committee, which deferred to Nalcor rather than dealing with our questions independently!
A copy of our letter to the Chair of the Oversight Committee is attached as Annex A (found at the end of this Post).
Annex B contains Jim Gordon’s original list of issues. A brief list of the issues follows and the reader can look to Annex B for the full statement of the issue, Nalcor’s response and replies compiled by Jim Gordon.
1. This is the first use of a “natural dam” containing quick clay in a hydro facility and this concern remains valid, notwithstanding Nalcor’s arguments to the contrary.
2. The safety criteria applied to a natural dam should be higher than those which apply to an engineered, constructed structure. There has to be a difference in the safety factor in natural dams, formed with a heterogeneous mixture of sand, silt and clay, as opposed to a constructed dam with homogeneous sections of carefully placed and compacted gravel, sand, and clay.
3. Canadian Dam Association Guidelines are simply guidelines which apply mainly to the operation of dams rather than to their construction. They apply primarily to constructed dams rather than natural dams.
4. Unlike a constructed dam, the strata of the North Spur are all sloping slightly downstream.
5. The more modern methodology used by Dr. Stig Bernander is more appropriate in assessing stability of the remediated North Spur than the limit equilibrium analysis which has been employed by Nalcor. Robin Dury has applied Bernander’s methodology and concluded that the North Spur is unsafe. These conclusions should prompt government to commission an independent geo-technical review panel.
6. Dr. Bernander has advised that Nalcor’s use of cut-off walls to remediate the North Spur may have a detrimental effect on its stability and needs to be investigated.
7. The upstream slope is too steep and requires further investigation.
8. Small landslides encountered upstream during construction should be recognized in calculating the stability of the North Spur. Such recognition should result in flatter slopes.
9. There is a deep hole downstream of the North Spur and its west slope is very steep. It should be investigated further by an independent expert panel.
10. The upstream slope below the low-drawdown reservoir level is too steep and reduces the safety factor. This requires independent assessment.
11. It is essential that there is no connection between the lower aquifer and the upstream reservoir. Further testing is needed to verify that water cannot flow from the reservoir into the aquifer.
12. A drill casing dropped under its own weight through very soft clay in several holes. This is very troubling. Does the dropping of a drill casing indicate the need for more testing, in the areas where the dropping occurred?
13. Geotechnical investigations need to be verified and retested using Dr. Bernander’s methodology. In addition additional testing is needed because linear relationships are not applicable at higher stress levels.
14. There is an anomaly in the relationship between tested shear strength and the liquidity index, as discovered by Maurice Adams. The relationship is well outside the normal range, indicating that one or the other is incorrect, but not both.
15. Engineering design work included remediation of the deep downstream hole, including a downstream berm extending out into the water and infilling of the deep downstream hole. Is there a need for such a berm and/or flattening the slope of the Spur as it extends to the bottom of the hole? Further study of the stability of the hole and the effect of erosion on the downstream shoreline of the Spur is required.
16. The new hydrogeological model Nalcor has used to examine the impact of impounding the dam on the water table needs further testing to ensure the North Spur is safe.
17. Quick clay has been found at two locations on the downstream slope but the geographical extent has yet to be determined. Further testing and additional boreholes will be needed.
18. Despite earlier reports that independent reviews have been conducted it is unclear if any such independent review has been undertaken by experts or consulting engineers who have not had prior involvement in the Muskrat Falls project. Review of the geotechnical design is still required and should be undertaken by a panel of independent experts and not by an engineering consulting firm.
19. The Independent Engineers appointed by the Federal government have not been mandated to conduct an independent review of the research into the stability of the North Spur.
20. Is there risk that the insurer of the North Spur will deny payment on any claim arising from failure of the dam, since this was a known and acceptable risk undertaken by Nalcor?
Robin Dury, in his recent Master’s Thesis at the Lulea University of Technology, has applied the more modern dynamic modelling that Dr. Bernander considers necessary to evaluate the North Spur. He concludes that the rise in the water level from 17 m to 39 m may trigger a landslide and that the “North Spur does not form a safe and reliable part of the impoundment wall.” This confirms Dr. Bernander’s conclusion that further study, including field investigations, are needed to ensure that the Muskrat Falls project can rely upon the safety and stability of the North Spur. The critical load bearing capacity of the natural dam will not be able to stand up to the pressure, which could exceed twice the capacity, which means the North Spur could fail when the reservoir is filled, based on Dury’s research.
It is essential that the engineering design be reviewed by a panel of geo-technical experts as proposed by Grand Riverkeepers of Labrador and Labrador Land Protectors who presented a petition signed by over 1000 people to the government of NL on May 9, 2017 to which no reply has yet been forthcoming.
Letter to the Chair of the Muskrat Falls Oversight Committee January 16, 2017
Chair, Muskrat Falls Oversight Committee and Clerk of the Executive Council
Executive Council Office
Government of Newfoundland and Labrador
We are writing to you in your capacity as Chair of the Oversight Committee to request that you consider the attached list of issues relating to the North Spur, compiled by retired engineer Jim Gordon, in collaboration with the undersigned and with other colleagues.
The North Spur is a hill 1,000m long which comprises part of the natural dam at Muskrat Falls, a dam which is both an advantage of the site, as well as its Achilles Heel. When the Muskrat reservoir is filled, this hill will form a natural dam containing the reservoir. The hill consists of two layers of sand, and two layers of quick clay, sloping downstream, on a deep foundation of quick clay, extending down to far below tidewater. Quick clay is similar to quicksand. It liquefies when disturbed or when it becomes saturated with water. There are numerous quick clay slides on the North shore upstream and downstream of Muskrat, including three large slides on the downstream slope of the North Spur.
NALCOR intends to increase these factors by flattening the slopes, adding a downstream berm, adding pump wells, placing an upstream impervious blanket to close off the upper sand layer, and building a cut-off wall filled with an impervious material to close off the lower sand layer. This means that the two layers of quick clay will remain within the body of the dam. To our knowledge, quick clay has never before been used to form part of a dam structure, nor has a dam been built on a quick clay foundation.
If the North Spur dam fails, there is a risk of loss of life in Goose Bay and Happy Valley. If the North Spur fails, the Muskrat Hydro facility would be left high and dry, and become a stranded asset, with a repair cost well over several billions. Power would be interrupted for several years. Since the design of the North Spur dam is without precedent, it is imperative to have the design reviewed by an independent panel of experts – a Review Board, to provide added assurance that the design is safe.
There has been no public forum for reviewing the North Spur and to test the research and remedial measures advanced by Nalcor’s geo-technical experts. The engineering design work had not been completed when the joint panel undertook its review so the panel could not test the effectiveness of the remedial measures that have been taken since the panel’s report of August 2011.
When public health and safety are at issue such critical independent assessment must be in public view, through a fully transparent process and conducted by a panel of geo-technical experts. It must be fully independent of the proponents and its engineering consultants. The “precautionary principle” requires that when a project imposes a potential risk to the public and the environment, and there is no demonstrated scientific consensus to refute such risk, then the proponent must provide evidence that the project will not be harmful. This applies in particular where extensive scientific knowledge on the matter is lacking. There is a social responsibility to protect the public from exposure to harm. The exercise of the principle calls for further scientific research and inquiry to provide sound evidence that no harm will result.
I am sure you share our concern that every measure possible must be taken to reduce risk, following the precautionary principle, even if it leads to an excess of caution over incaution by the project proponent. Not only is a huge financial investment at stake but, more importantly, failure of the dam has the potential to place people and communities at risk, through life-threatening unpredictable events! Better to err on the side of safety, when lives are in the balance!
We have been told that Nalcor has mitigated all the risks and that we should trust Nalcor to do the right thing. Is there any basis on which the public can have trust that Nalcor has left no stone unturned in its quest to maximize public safety and to minimize the risk of a devastating dam failure or earth slide? Sadly we do not think there is!
We are all familiar with the egregious cost overruns which have increased estimated project cost from $6.2 billion in 2011 to $11.7 billion in 2017. We are all familiar with the delay for full power from 2017 to the second quarter of 2020.
We are all familiar with egregious lapses in quality control on this project, including the leaking coffer dam, the “popped” transmission strand and the collapsing concrete cribbing. These lapses, and others, make it clear that quality control has been weak and, furthermore, that Nalcor is not capable of being its own project manager.
The performance of Nalcor is far from exemplary and provides no basis for trust that everything has been executed in accordance with the highest quality standards. It is not clear to us that the new CEO has instigated a “root and branch” transformation which will make Nalcor more open, transparent and accountable. From the outside there is little evidence of structural change, other than the separation of generation from transmission, and little change in senior personnel. In our opinion major changes in structure and senior personnel are essential. We are disappointed that the new CEO has chosen not to initiate an independent review of the design plan for remediation. We believe government must undertake such an independent review and that it should be expedited.
The undersigned wrote to your predecessor, Julia Mullaly, and to the Deputy Minister of Environment and Conservation, Jamie Chippett, on November 22, 2014, providing a copy of the PowerPoint presentation made by Dr. Stig Bernander at the LSPU Hall on October 30, 2014.
In our covering letter we made the following statements:
If Dr. Bernander is correct and the right engineering research and associated mitigation measures are not undertaken, assuming that mitigation is even possible, the risks of a catastrophic failure of the North Spur, which include the loss of the project and downstream flooding, are significant.
The Joint Environmental Panel concluded that the loss of the Muskrat Falls dam would result in the "inundation" of Mud Lake and the lower part of Happy Valley Goose Bay, with only two hours of notice, causing immense property damage. Two hours’ notice would not provide sufficient time to evacuate all those who would be in the path of a wall of water and there would likely be loss of life.
If we were in your position we would want to know that we took all necessary measures to ensure that the risks of such an eventuality are reduced to the extent possible and urge you both to exercise your responsibilities by getting the best independent advice possible.
The attached list provides a compelling case for the appointment of such a review panel independent of Nalcor. It delineates the risks which remain outstanding and complements the work done by Dr. Stig Bernander, whose most recent research has been presented to the Public Utilities Board and can be viewed at http://www.pub.nl.ca/applications/IslandInterconnectedSystem/phasetwo/chronologically_grandriverkeeper.php .
Jim Gordon concludes as follows: It is essential that the dam design be reviewed by a panel of geotechnical experts. It is not too late to undertake such a review, since any changes resulting from the review can still be built. If there are no changes required, then there is the added assurance that the dam is safe.
An independent review of the geo-technical research and remediation for the North Spur should be embraced openly as a prudent course of action. This review should be initiated by government, given Nalcor’s defensive posture and its failure to take action on its own.
The undersigned would be pleased to meet with you to discuss this matter. We also recommend that you invite Jim Gordon to meet with your committee to explore his concerns, along with options to deal with this major problem.
You are now the most senior official in the government. Because of our own personal experience we know what an immense responsibility that is. You have both the opportunity and the responsibility to recommend that government take the prudent steps we suggest. We look forward to your response.
David Vardy and Ron Penney