Environmental Sensitivity mapping for
Oil Spill Contingency Planning and Response
Coastlines are at risk during marine oil spills
because of the high likelihood of direct contact with oil when floating
slicks reach the shoreline. Oil fate and impacts vary significantly
depending on shoreline type and biological resources. There are also
frequently human-use, economic, and aesthetic issues in coastal areas that
must be considered as well.
The Environmental Sensitivity Index (ESI) system is
an international scheme that classifies and ranks the overall sensitivity
of different coastal habitats to oil spills. Several
factors are used to determine the sensitivity of the coast including:
substrate type (sand, mud, rock, mixed, etc.), exposure to wave action,
slope of the shore, general biological productivity and ease of cleanup. Key to the rankings is an understanding of the relationships
among physical processes, substrate type and associated biota that produce
predictable patterns in oil behavior, persistence and biological impact.
ESI are usually determined using a combination of
topographic maps, aerial photographs and/or other remote sensing data. The
ESI classification is verified in the field and supplemented with other relevant
information. The ESI classifications are normally
presented on maps at a scale appropriate for response and cleanup activities. In addition these maps show:
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Natural Resources (sensitive or rare animals, plants and habitats)
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Human-Use Resources (recreational beaches, parks, marine
sanctuaries, fish farms, water intakes, quarries, archaeological sites,
etc.)
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Recommended shoreline protection techniques and
counter-measures
The key requirement of the ESI map is to convey to
non-specialists an instant message regarding the relative sensitivity of
coastal habitats in an impact area. In so doing, the ESI maps can be used
by policy administrators, decision-makers, response organizations, and
scientists.
The information contained in ESI maps is essential
for:
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Setting protection priorities in contingency planning and emergency
response procedures,
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Selecting cleanup strategies and procedures in case oil does reach
the shore and
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Providing input data for Environmental Impact Assessments (EIA)
and Environmental Risk Assessments (ERA).
Because of its simplicity, flexibility and wide
applicability, ESI mapping is now accepted as the defacto world-wide standard for coastal resource sensitivity
analysis in relation to oil spills.
Akvaplan-niva is the only organization in
Scandinavia conducting shoreline mapping following globally accepted ESI
principles and other national procedures. During the process, we draw
upon in-house expertise in coastal ecology, EIA/ERA, image analysis and
interpretation, and our GIS and mapping department to provide an
integrated (digital) environmental atlas of maps.
Other related activities carried out be
Akvaplan-niva include the development of the Norwegian national
beach-cleanup guidelines prepared for the State Pollution Control
Authority, coastal resource surveys, baseline and environmental monitoring
surveys, and oil spill reconnaissance surveys.
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