Tidal Power and Migratory Ice in the Minas Region of the Bay of Fundy, Canada

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THE VIEW FROM SPACE of the Inter-Tidal Mudflats in the Minas Region of the Bay of Fundy, Where Thousands of 10 to 100 Tonne Cakes of Ice Migrate From the Mudflats into the Tidal Currents Each Winter
PHOTOS: MASSTOWN, Nova Scotia, of Sediment-Laden Ice
PHOTOS: SHUBENACADIE, Nova Scotia, of Sediment-Laden Ice
PHOTOS: MAITLAND, Nova Scotia, of Sediment-Laden Ice
PHOTOS: SUMMERVILLE, Nova Scotia, of Sediment-Laden Ice
PHOTOS: PARRSBORO, Nova Scotia, of Sediment-Laden Ice (Under Construction)
PUBLICATION 2011: SUMMARY OF IMPACT OF ICE ON THE HARVEST OF TIDAL ELECTRICITY IN THE BAY OF FUNDY, CANADA 2006-2011
PUBLICATION 2010: OpEd
2009 TESTING BUOYANCY of Samples of Sediment-Laden Cakes of Ice Grounded on the Inter-Tidal Mudflats of the Minas Region of the Bay of Fundy
PUBLICATION 2008: REVIEW OF EVIDENCE for Sub-Surface Ice in the Bay of Fundy
PUBLICATION 2008: ENGINEERING ISSUES IN THE HARVEST OF TIDAL POWER
PUBLICATION 2007: SUMMARY AND UPDATE of Surface Ice in the Bay of Fundy
PUBLICATION 2006: DOCUMENTATION of Surface Ice in the Bay of Fundy

 

'Easterlies Over Minas Ice Ebbing,

Tidal Turbines Take Warning' 

  

Copyright © 2008-2016 by 

Richard Sanders

Contact: resourcemanage@eastlink.ca

 

NO REPRODUCTION OF PHOTOGRAPHS  OR VIDEOS WITHOUT WRITTEN PERMISSION

 

 

VIDEOS of MINAS ICE

 
 
 
 
PHOTO SUMMARY of
MINAS ICE.  
 
 
1. Ice in the Minas Basin

258-1.jpg

vast floe of ice is forced into the
eastern end of the Minas Basin
by the flood tide.  
Floes of pack ice can reciprocate through
the Minas Passage with each tidal cycle
from December to April,

 
 
2. Ice in the Minas Passage: Western View.

1208-2.jpg

 Cape Split is located at the western entrance
to the Minas Passage,
the most powerful tidal resource
in North America below the 60th parallel, ice extends from the Minas
Basin through the Minas Passage
towards the Gulf of Maine.  
In the photo above thousands of ice blocks
are compressed into a vast ice floe
by the tidal currents in the Minas Passage.
Incoming tide is flowing from right to left.

 
 
 
3. Ice in the Minas Passage: Eastern View.

1151-3.jpg

Cape Blomidon marks the eastern entrance
to the Minas Passage.
This photo and the photo of Cape Split
(photo 2, above) capture most of the
Minas Passage,
where hundreds of tidal current
harvesting devices are to be installed
[Nova Scotia Department of Energy:downloaded from www.gov.ns.ca/energy  (November, 2010)].  
The approximate location of the test site
for prototype devices is indicated by
the white arrow in photo 3 (above).  
Cape Split is to the right of the test site.
For much of the 2015 Minas Ice Season
(December 21, 2014-April 1, 2015), ice
moved back and forth through
the Minas Passage.
Captured in this March 10, 2015, photo,
a floe of pack ice is migrating through
the Minas Passage into the  Minas Basin,
driven by the flood tide.  
As documented elsewhere, this pattern of
Minas Ice accumulation is common.

 
 
 
 
4. The Dimensions of Ice Blocks

RClark.jpg
Photo of R. Clark by M. Clark. Used with permission.

The size of a pack ice component
becomes apparent when it is grounded
by retreating tides.  
In the photo above, a man (barely visible at tip of white arrow) is standing next to
a large ice block grounded on the 
intertidal mudflats of the Minas Basin
at Summerville, Nova Scotia.  
Note the brown sediment accumulation
in the large ice block.
 
 
 
5. Sediment incorporation reduces ice block buoyancy.
 
IMG_0790.jpg

render ice blocks 
Neutrally or negatively buoyant ice
blocks, migrating at any depth
in the water column
or tumbling along the ocean floor,  
would be carried by tidal currents
toward tidal current harvesting devices.  
Contact between neutrally buoyant
ice blocks and tidal devices
may result in accelerated depreciation
or catastrophic failure.

 
 
 
 
 
Sediment-Laden Ice Blocks
Pose a Danger to
Tidal Electricity Devices 
 
 
As can be see from the photos on this site
ice blocks frequently incorporate sediment from the
intertidal zone during cycles of grounding/freezing
and re-floating, and sediment incorporation
reduces the buoyancy of ice.
 
 
Thousands of sediment-laden cakes of ice of
unkonwn buoyancy migrate each winter
(for photos, see this site) from the 
of the Minas Basin in the Bay of Fundy
into the tidal streams which are to be used
to generate electricity in Nova Scotia's Minas Passage

I am concerned that some of these sediment-laden cakes
are not positively buoyant but will nonetheless
be propelled beneath the water's surface
to the Minas Passage  to make contact
with the hundreds of tidal current harvesting
devices to be installed in this narrow channel, whose
If one knew the number of large sediment-laden
ice blocks transiting the Minas Passage
per ice season, the probability of
ice block-tidal device collisions
could be calculated, using the size of each device
and the number of installed devices.
 
For example, if no sediment-laden ice blocks
traverse the Minas Passage per year,
the collision risk for all installed tidal turbines is zero.  
 
On the other hand, if 1,000 large sediment-laden
neutrally or negatively buoyant ice cakes
reciprocate back and forth through the Minas Passage
during Minas Ice Season, then the possibility
of collision damage to some fraction of the
installed tidal devices may be significant.
 
The frequency of large submerged ice blocks
traversing the Minas Passage
should be determined to quantify
the risk to tidal devices.
Thfff
 The Government of Nova Scotia  should
conduct a year-long census of the
 sub-surface traffic 
through the Minas Passage 
. 

 Actually the situation is more comples.