Post on 20-Jun-2020
Antoine BoissonCentre d’études nordiques
Université Laval, Québec, Canada
antoine.boisson.1@ulaval.ca
Coastal Classification of Nunavik &
Dynamics of the Arctic/Subarctic coastal environments
Michel Allardmichel.allard@cen.ulaval.ca
Background
≈ 10,000 km (CanVec)
4 % of Canada’s coastline
Nunavik’s coastline
Eastern coast of Hudson Bay
Southern coast of Hudson Strait
Coast of Ungava Bay
Inhabited by 14 Inuit communities & 1 Cree community
Context of global warming
Permafrost thaw, hydrodynamic changes, etc.
Context of high economical potential
Mines, port infrastructures
Emerging coasts; Sea level fall
Hydrodynamic conditions
HB: wave-dominated
HS-UB: tide-dominated
Sea ice is a defining seasonal feature of this coastline.
3
Post-glacial marine transgression (D’Iberville)
Post-glacial marine transgression (Tyrrell)
Marine limit (m)
Vincent, 1989
Ungava
Bay
Hudson Bay
James
Bay
Nunavik is influenced by ongoing glacio-isostatic
uplift, with current emergence rates of about 5 to
13 mm/yr, counterbalancing the rising relative sea-
level in the context of climate change.
Background
4
James et al., 2014
Kuujjuaq, QC
0.8 mm/yr
Inuvik, NT Iqaluit, NUInukjuak, QCKuujjuarapik, QC
1.37 mm/yr 1.05 mm/yr
Where the land is rising rapidly, due to postglacial
rebound, sea level is projected to continue to fall.
The total expected sea level change over the period 1995-2100 is
more than 1 m for Kuujjuarapik and Inukjuak; 80 cm for Kuujjuaq.
Background
Post-glacial marine transgression (D’Iberville)
Post-glacial marine transgression (Tyrrell)
Marine limit (m)
Vincent, 1989
Ungava
Bay
Hudson Bay
James
Bay
Main questions
What are the different types of coast?
Are they in erosion? In progradation? Why?
What are the coastal hazards? & which communities are the most vulnerable?
Objective
To collect audio descriptions, photos and videos of the coastal zone in order to help to
interpret the shoreline type and create a digital shoreline database.
Material
Bell Helicopter 206 Long Ranger
JVC Pro GY-HM100U video camera
Nikon D7100 camera
VMS 333 (Video Mapping System)
6
VMS-333
GPS
Microphone
Camera
VMS-333
battery
eSPACE: emergency Spatial Pre-SCAT for Arctic Coastal Ecosystems.
SCAT: Shoreline Cleanup Assessment Technique.
In 2009, Environment Canada initiated a national project in the Canadian Arctic to improve emergency
preparedness and response related to potential oil spills and their impact on coastal ecosystems.
Geotagged shoreline videography and photography by helicopter
7
Wynja et al., 2015
Geotagged shoreline videography and photography by helicopter
Flight characteristics
Spatially referenced: video with x, y coordinates
Low altitude: around 90-120 m
Close to shore: 100-150 m
Oblique video: 45°
Web Map
National Wildlife Research Center
Carleton University
Environment Canada
Geotagged shoreline videography and photography by helicopter
45h of video recordings & 37,000 photos (7,200 km)
Wynja et al., 2015
Coastal segmentation and classification
Shoreline database
Mapping procedure is based on
shoreline segmentation defined by
the eSPACE project.
Descriptive attributes (substrate,
slope, shore type, exposure) are
input into a custom data entry
form for each shore segment to
describe both the alongshore
segment and the cross-shore
morphology (intertidal, supratidal
and backshore zones).
SCAT: Shoreline Cleanup Assessment Technique.
Hudson Strait
Mixed & Coarse
Sediment Tidal Flat
++++
Bedrock Cliff/Vertical ++++
Bedrock Sloping/Ramp ++++
Boulder Beach ++++
Pebble/Cobble Beach +++
Mixed Sediment Beach ++
Sand Beach +
Sand Tidal Flat +
Mud Tidal Flat – Marsh +
Bedrock Platform +
Man-Made +
Ungava Bay
Bedrock Sloping/Ramp ++++
Mixed & Coarse
Sediment Tidal Flat
++++
Boulder Beach ++++
Mud Tidal Flat – Marsh ++++
Bedrock Platform +++
Sand Tidal Flat ++
Mixed Sediment Beach ++
Bedrock Cliff/Vertical ++
Pebble/Cobble Beach ++
Man-Made +
Sand Beach +
Hudson Bay
Pebble/Cobble Beach ++++
Bedrock Sloping/Ramp ++++
Bedrock Platform +++
Boulder Beach +++
Mixed Sediment Beach +++
Sand Beach ++
Mixed & Coarse
Sediment Tidal Flat
++
Mud Tidal Flat – Marsh +
Bedrock Cliff/Vertical +
Sand Tidal Flat +
Man-Made +
Coastal segmentation and classification
Rocky coasts
Key points
Mosaic of rocky coasts.
Continually affected by frost-weathering
processes since the withdrawal of the
Laurentide Ice Sheet and following
emergence from the postglacial sea.
No coastal retreat, except cliff stretches.
Fjords and talus cones between Ivujivik and Salluit, Hudson Strait
Mosaic of beaches
Key points
A general progradation of sedimentary environments (beaches, sand spits, tombolos, tidal flats, deltas).
Few eroded coastlines.
Development of dunes, wetlands, lacustrine environments.
Raised beaches.
Emerging De Geer moraines between Akulivik and Ivujivik, Kovik Bay
21
Components of a De Geer
moraine (DGM) coastline
along the Kovik River valley.
A prograding coast.
A “gridded pattern” of De Geer
moraines, drumlinoid ridges,
eskers, and inter-moraine
depressions structures the
coastal system into short
beaches and spits, tombolos,
small bays and pocket coastal
marshes.
De Geer moraine
coastlines
Tidal flats
Key points
Mostly in Ungava Bay
A general progradation
Boulder-strewn tidal flats, 7 km northwest of Tasiujaq, Leaf Basin, Ungava Bay
25
Permafrost coasts
An eroding permafrost coastline with ice-wedge polygons, 10 km southwest of Salluit, Sugluk Fjord
26
Permafrost coasts
An eroding permafrost coastline with a micro-cliff and thermokarst lakes, 55 km north of Puvirnituq
27
Permafrost coasts
Key points
Few eroded permafrost coastlines.
Thermo-erosion gullies, thermokarst lakes.
Aggradation of permafrost in intertidal and
supratidal zones.
Eroding permafrost bluff on the bank of permafrost plateau in Manitounuk Strait, 40 km northeast of Kuujjuarapik
28
Storm surge flooding risk
Storm surge
Temporary difference between theexpected water level and that experiencedat a location due to extreme meteorologicalconditions such as low atmosphericpressure and strong onshore winds.
Positive storm surges (surcotes) will be
more numerous and stronger on all the
coasts of Nunavik (Massé and Gallant,
2016).
Negative storm surges (decotes) will be
more numerous and/or stronger on the
coast of HB, but fewer on the coasts of HS
and UB (Massé and Gallant, 2016).
Storm surge flooding in Salluit
NOAA
30
Aubé Michaud et al., 2017The risk of storm surge flooding is very high. Five newly built houses
could be flooded in the case of a positive storm surge of 1.2 m.
Akulivik
Storm surge flooding risk
31
Au
bé
Mic
hau
d e
t al., 2
01
7S
torm
su
rge f
loo
din
g r
isk
Quaqtaq
IvujivikPuvirnituq
Kangiqsujuaq
32
In the context of climate change, this coastal
hazard should be better understood and
managed in the next few years.
Makeshift seawall in Salluit
Eroded coastline in Umiujaq
Storm surge flooding risk
33Clerc et al., 2012
Ice pushes
Bleau (2012)
Lateral pressure caused by the
extension of ice on bays, straits
and lakes. Sea ice is forced by
waves and strong onshore
winds to lie upon the coast.
Once on the banks, the ice
pushes and scours beach
sediments to form bulges below
and above the high tide zone.
35
The erosion and leveling of emerging rocky coasts; No coastal retreat, except
cliffs.
The erosion and the reworking of sediments of emerging landforms such as De
Geer moraines and drumlinoid ridges;
The progradation of sedimentary environments such as beaches, dunes (nebkhas,
embryo dunes), spits, tidal flats;
The aggradation of permafrost in intertidal and supratidal zones; Few eroded
permafrost coasts;
Some coastal risks.
Key points