Canadian Dam Association Bulletin - Summer 2017 - 31

Figure 8: Discharge at Lawn during Hurricane Igor

Operations staff was based out of a
small local office on the same property and were easily able to respond
with minimal risk of being stranded,
but the high water levels did wash out
the access road to the powerhouse
property. Temporary access was
gained through an adjacent property.
Operations staff responsible for
the Lawn, West Brook and Fall Pond
development is based out of a local
office approximately forty (40) kilometres from the Lawn development,
making access significantly more difficult. As a result of the access challenges, in some cases the latest available
information was being received though
media reports. This was the case with
the Fall Pond Dam, Newfoundland
Power became aware of waves overtopping the Fall Pond concrete gravity
structure via media reports.
Newfoundland Power's engineering staff are centrally located in St.
John's, over 300 km from both sites.
In addition to dam safety, the team
provides civil support to the company.
Engineering staff were not deployed
in advance of the storm as there was
uncertainty in storm track and most
of Newfoundland Powers dam infrastructures, including most of its higher
consequence structures, are located
near St. John's.
The damage to the road infrastructure was unprecedented and
unforeseen. Transportation was
limited due to washout of numerous stream crossing. Newfoundland
Power was unable to visit the Lawn
Canadian Dam Association * Summer 2017

Figure 9: Flooding at Port Union During Hurricane Igor; Whirl Pond (left) and Powerhouse (right)

and Port Union developments to survey the damage until September 24th
using a helicopter. The delay was a
result of helicopter resources being
used for aid operations, and resources the company could access being
used to restore key components of
the electrical system. After the storm,
road transportation on the Burin
and Bonavista Peninsulas was limited due to the washout of numerous
stream crossings.
Hurricane Igor highlighted the
weakness of transportation systems
in the event of a major hurricane event.
Newfoundland Power's Dam Safety
Emergency Preparedness Plan provided details on access routes, location
of off-road vehicles and provision for
air transport via helicopter however at
the peak of the storm and immediately
following, transportation was nearly
impossible. As a result, Newfoundland
Power had limited ability to provide
any physical response and had the
damage progressed, response would
have been limited to communication.
The incident highlighted the importance of good communication and
timely dispatch of employees tasked
with observation.
The event also highlighted the
fact that any emergency planning
and preparation should consider the
effects of storms beyond the IDF of the
dam in question, particularly when
considering structures with lower
IDFs. The breakdown of the road and
communication networks is plausible
at these higher flood frequency's.

4.1 Port Union Development
At Port Union, the plant was inundated by approximately two (2) metres
of water causing extensive damage to
the generators, switchgear, doors and
windows. The flooding caused the
Whirl Pond Dam to be overtopped
by approximately 0.3m causing significant erosion of the filter and
semi-impervious layers exposing the
corrugated steel core in places. Two
freeboard dams on Whirl Pond were
significantly damaged while one other
was damaged. The dam and Long Pond
was overtopped with minor damage
occurring on the timber structure
but significant erosion occurring on
one abutment.
Newfoundland Power was able to
secure a contractor to complete the
work during the Month of November.
The design crest of Whirl Pond Dam
was increased by 300mm to at least
provide for a crest adequate for
another hurricane similar to Igor.
This was achieved by adding an additional 300mm of semi-impervious fill
in place of the existing 300mm filter
than adding a top layer of 300mm
of rockfill. A 300mm riprap parapet was to be than added on top for
freeboard protection.
Because of the short construction window Newfoundland Power
elected to reuse the existing filter
where possible, supplementing it
where necessary with additional
material instead of the rock fill. The
freeboard dams were found to be
slightly lower than the crest at Whirl
31



Table of Contents for the Digital Edition of Canadian Dam Association Bulletin - Summer 2017

Board of Directors
President's Message
Roller Compacted Concrete Buttress at the Site C Clean Energy Project
Hurricane Igor's Impact on Newfoundland Power's Small Hydro
CDA Conference Heads to Kelowna!
CDA Directors & Officers - Call for Nominations
2017 CDA Awards - Call for Nominations
CDA Developing New Ways to Distribute Guidelines
Notice of Annual General Meeting
Time to Renew Your Membership
Buyers' Guide and Trade List
Canadian Dam Association Bulletin - Summer 2017 - intro
Canadian Dam Association Bulletin - Summer 2017 - 1
Canadian Dam Association Bulletin - Summer 2017 - 2
Canadian Dam Association Bulletin - Summer 2017 - 3
Canadian Dam Association Bulletin - Summer 2017 - 4
Canadian Dam Association Bulletin - Summer 2017 - 5
Canadian Dam Association Bulletin - Summer 2017 - 6
Canadian Dam Association Bulletin - Summer 2017 - Board of Directors
Canadian Dam Association Bulletin - Summer 2017 - 8
Canadian Dam Association Bulletin - Summer 2017 - President's Message
Canadian Dam Association Bulletin - Summer 2017 - 10
Canadian Dam Association Bulletin - Summer 2017 - 11
Canadian Dam Association Bulletin - Summer 2017 - Roller Compacted Concrete Buttress at the Site C Clean Energy Project
Canadian Dam Association Bulletin - Summer 2017 - 13
Canadian Dam Association Bulletin - Summer 2017 - 14
Canadian Dam Association Bulletin - Summer 2017 - 15
Canadian Dam Association Bulletin - Summer 2017 - 16
Canadian Dam Association Bulletin - Summer 2017 - 17
Canadian Dam Association Bulletin - Summer 2017 - 18
Canadian Dam Association Bulletin - Summer 2017 - 19
Canadian Dam Association Bulletin - Summer 2017 - 20
Canadian Dam Association Bulletin - Summer 2017 - 21
Canadian Dam Association Bulletin - Summer 2017 - 22
Canadian Dam Association Bulletin - Summer 2017 - 23
Canadian Dam Association Bulletin - Summer 2017 - Hurricane Igor's Impact on Newfoundland Power's Small Hydro
Canadian Dam Association Bulletin - Summer 2017 - 25
Canadian Dam Association Bulletin - Summer 2017 - 26
Canadian Dam Association Bulletin - Summer 2017 - 27
Canadian Dam Association Bulletin - Summer 2017 - 28
Canadian Dam Association Bulletin - Summer 2017 - 29
Canadian Dam Association Bulletin - Summer 2017 - 30
Canadian Dam Association Bulletin - Summer 2017 - 31
Canadian Dam Association Bulletin - Summer 2017 - 32
Canadian Dam Association Bulletin - Summer 2017 - 33
Canadian Dam Association Bulletin - Summer 2017 - 34
Canadian Dam Association Bulletin - Summer 2017 - 35
Canadian Dam Association Bulletin - Summer 2017 - CDA Conference Heads to Kelowna!
Canadian Dam Association Bulletin - Summer 2017 - 37
Canadian Dam Association Bulletin - Summer 2017 - 38
Canadian Dam Association Bulletin - Summer 2017 - 39
Canadian Dam Association Bulletin - Summer 2017 - 40
Canadian Dam Association Bulletin - Summer 2017 - 41
Canadian Dam Association Bulletin - Summer 2017 - 42
Canadian Dam Association Bulletin - Summer 2017 - 43
Canadian Dam Association Bulletin - Summer 2017 - 44
Canadian Dam Association Bulletin - Summer 2017 - 45
Canadian Dam Association Bulletin - Summer 2017 - CDA Directors & Officers - Call for Nominations
Canadian Dam Association Bulletin - Summer 2017 - 47
Canadian Dam Association Bulletin - Summer 2017 - 2017 CDA Awards - Call for Nominations
Canadian Dam Association Bulletin - Summer 2017 - 49
Canadian Dam Association Bulletin - Summer 2017 - CDA Developing New Ways to Distribute Guidelines
Canadian Dam Association Bulletin - Summer 2017 - 51
Canadian Dam Association Bulletin - Summer 2017 - 52
Canadian Dam Association Bulletin - Summer 2017 - Notice of Annual General Meeting
Canadian Dam Association Bulletin - Summer 2017 - Time to Renew Your Membership
Canadian Dam Association Bulletin - Summer 2017 - Buyers' Guide and Trade List
Canadian Dam Association Bulletin - Summer 2017 - 56
Canadian Dam Association Bulletin - Summer 2017 - 57
Canadian Dam Association Bulletin - Summer 2017 - 58
Canadian Dam Association Bulletin - Summer 2017 - 59
Canadian Dam Association Bulletin - Summer 2017 - 60
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