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.
Conclusion
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.
David Vardy
______________________________
Annex A
Letter to the Chair of the Muskrat Falls Oversight
Committee January 16, 2017
Bernard Coffey
Chair, Muskrat Falls Oversight Committee and Clerk
of the Executive Council
Executive Council Office
Government of Newfoundland and Labrador
Dear Sir:
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.
Respectfully,
David Vardy and Ron Penney
Annex B
