ShoreZone Verification in Preparation for Marine Oil Spills

July 01, 2016

Unconsolidated segments of shoreline, including sand, pebble and boulder beaches, increase
marine biodiversity by providing habitat variation in intertidal and subtidal environments. Small
pocket beaches are of particular ecological importance, especial

Unconsolidated segments of shoreline, including sand, pebble and boulder beaches, increase
marine biodiversity by providing habitat variation in intertidal and subtidal environments. Small
pocket beaches are of particular ecological importance, especially in bedrock-dominated fjord
environments, as they provide hydrodynamic refuge and high quality feeding grounds for
juvenile fish, including salmon. These areas, however, are also particularly sensitive to marine
oil spills, as the interstitial spaces between the sediment particles can trap oils and allow for
resuspension on subsequent tides. Unconsolidated beaches also cause complications for marine
response teams, as the sediments must often be completely removed if contaminated. Accurate
knowledge of both the location and area of sensitive beach habitats is therefore critical,
particularly in areas of heavy tanker traffic. We collected ground-truth GPS points at all
segments of unconsolidated shoreline for six islands in the Douglas Channel, British Columbia,
to quantify the accuracy of ShoreZone, an available and widely used shoreline database. We
found that, due largely to its coarse spatial resolution, ShoreZone greatly overestimates the total
amount of unconsolidated beach on these islands, while failing to identify important pocket
beaches. Further, the ShoreZone database does not provide reasonable estimates of beach area.
We explored other possible methods to develop accurate physical shoreline data for the British
Columbia coastline, including the use of terrestrial laser scanning data and satellite and aerial
imagery. Our results highlight the need for improvements in physical shoreline classification, as
well as the importance of accuracy assessments of large datasets.

Last updated by Alaska Regional Office on 05/15/2018

ShoreZone Habitat Conservation