Transcript SENSITIVITY, EXPOSURE, AND VULNERABILITY TO PETROLEUM POLLUTION, GJOA HAVEN COASTLINE, NU A Contribution to ArcticNet Project 1.2 Norm Catto ([email protected]) and Stephanie.

SENSITIVITY, EXPOSURE, AND VULNERABILITY TO PETROLEUM POLLUTION, GJOA HAVEN COASTLINE, NU
A Contribution to ArcticNet Project 1.2
Norm Catto ([email protected]) and Stephanie Papadimitriou ([email protected])
Memorial University, St. John’s NL A1B 3X9 Canada
Study of sand and gravel beaches showed differences in
morphology, sedimentology, energy regime, and
sediment transport. These characteristics change the
fate and effect of petroleum contamination on each
beach. Beaches have been ranked on their sensitivity to
oil pollution based on their physical characteristics.
Gjoa Haven lies along the Northwest Passage. With
ongoing reductions in ice cover, interest in the use
of the Northwest Passage as a transportation route is
growing. The visit of a small cruise ship in summer
2006 also indicates that the potential exposure to
petroleum contamination from marine vessels is
increasing. The cultural and socio-economic
significance of coastal activity, coupled with the
potential for increased traffic and tourism, indicate
that the potential impact of petroleum
contamination is significant.
Gjoa Haven, looking west across the harbour. The shallow, restricted
harbour could be readily isolated from an offshore oil spill, if suitable
equipment was available. A spill within the harbour would present
significant difficulties in clean-up.
The Gjoa Haven beaches are sand and gravel
dominated. However, most of the sediment represents
relict deposition and reworked glaciomarine deposits,
rather than reflecting the present coastal dynamics.
Present wave activity is generally insufficient to move
clasts.
Petroleum contamination potentially can come from both
offshore and terrestrial sources. The degree of exposure to
potential petroleum contamination from both offshore and
terrestrial sources forms a basis for assessment of the risk
of contamination on each beach. At Gjoa Haven, only the
interior harbour is exposed to potential contamination from
terrestrial sources. The entire coastline could be affected by
an offshore event.
Low energy, dissipative beach system dominated by shore parallel
transport, western shoreline. This beach system would be exposed
to offshore petroleum contamination resulting from offshore traffic.
The movement of sediment and marine detritus in
the nearshore and beach environments provides
analogies for how oil will behave. Lower energy
beaches will not self-clean as well as high energy
reflective beaches, and are more sensitive to
pollution. Although the beaches in the Gjoa Haven
area are composed of sand and gravel, they are
effectively low energy dissipative systems, and
would not effectively self-clean. This increases the
sensitivity of the coast to petroleum contamination.
Seasonal ice shove influences substrate configuration and texture, which in
turn affects sensitivity to petroleum contamination.
Gravel-dominated system, southeast of Gjoa Haven harbour. The clasts
were deposited by glaciomarine processes. All clasts larger than coarse
pebbles are not mobilized by wave action.
Coarse clasts are
immobile under
wave action but are
moved by seasonal
ice shove.
Low energy
sandy
beaches
with organic
detritus are
particularly
vulnerable.
Consideration of the risk of contamination from all
sources, in combination with sensitivity analysis, will
allow a vulnerability assessment. Compilation is in
progress. The vulnerability assessment can be used as a
basis for planning and allocation of resources, to cope
with petroleum pollution and to promote an effective
response to a potential major event.