ShoreZone is a mapping program that acquires obliqueaerial images at low altitude during the lowest daylighttides of the year to inventory alongshore and across-shoregeomorphological and biological features of thePacific Northwestintertidal shoreline.Habitat attributes are interpreted from the aerial images and categorized in ageographic database. Themapping program was first developed as anoil spill response tool forBritish Columbia, and now ShoreZone extends fromOregon toAlaska. Other uses of the spatial data includeecological studies,marine conservation planning, shoreline erosion monitoring,coastal flooding and vulnerability assessments, developingclimate change adaptation strategies, andcommunity education.[2][3]
A ShoreZone imaging and mapping prototype was originally developed by Dr. Ed Owens and demonstrated onSalt Spring Island,British Columbia in 1979.[4] A decade of further development resulted in the first protocols for the Physical Shore-zone Mapping System published by theBritish Columbia Ministry of Environment and Climate Change Strategy.[5] A compatiblebiological classification was developed in the early 1990s and the fully integrated biophysical mapping system was first applied toGwaii Haanas National Park and the remainder of British Columbia imaged and mapped from 1991 to 2007. The State ofWashington was imaged and mapped between 1994 and 2000,[6] and the coast ofOregon was imaged in 2011 and mapped in 2013.[7] The Alaska program began in 2001 when theCook Inlet Regional Citizens Advisory Council contracted Coastal and Ocean Resources Inc. to image and mapCook Inlet, and as of 2022 the Alaska program is on-going (see map). The spatially contiguous database of imagery and habitat attributes now includes over 100,000 km of shoreline.[8] In 2014, Dr. Carl Schoch of Coastwise Science pioneered the use ofStructure From Motion usingMicrosoft Photosynth to orthorectify ShoreZone oblique aerial imagery and to generate a point cloud of photographed objects used to produce a three-dimensional model of the shoreline. The concept was derived from theArgus Coastal Monitoring Systems that observe and quantitatively document the coastal environment. These systems typically employ a group of fixed digital video cameras mounted with overlapping fields of view taking consistently timed images of the nearshore zone that are merged and orthorectified in post-processing.[9][10] The digital post-processing of the ShoreZone imagery using Structure From Motion allows for quantitative measurements of shoreline unit dimensions, percent cover ofsubstrate, percent cover of macro epiflora and epifauna, and time series assessments of shoreline change. In areas where a temporal sequence of imagery exists, such as in Cook Inlet, Alaska, and the north coast of British Columbia, the time series are analyzed to quantify shorelineerosion oraccretion, vulnerability to flooding in the context ofsea level rise, and changing wave dynamics. Since 2016, commercial software is used to digitally process the aerial images to createorthophotomosaics and shoreline elevation models.[11] The ShoreZone imaging and mapping protocols were revised in 2016 to utilize thesenew technologies. The Alaska portion of the ShoreZone database is now part of theAlaska Ocean Observing System and theIntegrated Ocean Observing System.
The ShoreZone mapping program is maintained by a unique consortium with no binding agreement. The consortium currently consists of over 50 local, regional, and national partners including First Nations, various commercial industries, non-profits, state, provincial, and federal governments. This partnership won the 2009 Coastal America Spirit Award that recognizes "exceptional projects that demonstrate the 'spirit' of teamwork for group efforts that are poised to address our challenging coastal issues.”[12] In the United States, theOregon ShoreZone program is supported by theOregon Department of Fish and Wildlife and theOregon Coastal Management Program. TheWashington ShoreZone program is supported by theWashington Department of Natural Resources. The Alaska ShoreZone program has on-going support from theNational Marine Fisheries Service (NMFS) of theNational Oceanic and Atmospheric Administration (NOAA) that also manages and distributes the imagery and data.[13] In Canada, the British Columbia ShoreZone data is distributed by GeoBC.[14]The Nature Conservancy coordinated the program until 2016.[15]
Coastal resource managers need an inventory of habitats and associated biota that are threatened by increasing development and encroachment along coastal areas, as well as indirect effects of human activities. Coastal mapping efforts, such as ShoreZone, to a large extent fulfill these needs by providing physical and biological characterizations of the shoreline. The ShoreZone imagery and maps were originally intended as an oil spill response tool, and notably the data have been used in several emergency situations including the grounding in 2012 of the drilling bargeKulluk nearKodiak, Alaska.[16] Although the majority of users access only the imagery, the regional scale habitat attribute data have been used forecological modelling andmarine conservation planning.[17][18] More recently the data are benefitingNOAAclimate resilience studies.[19] Recent improvements in quantifying habitat attributes allow for analytical studies such as estimating potentialBlue Carbon resources ofsalt marshes.[20] The imagery also has aesthetic appeal and is used for educational content,[21] art exhibits,[22] exploring,[23] books,[24] and story maps.[25]
Over 450 ground stations were established to inform the mapping process and to evaluate the accuracy of the interpreted aerialimagery. The utility of ShoreZone maps for change detection was assessed by independent reviewers in 2009 and 2011, and findings include: 1) the NOAA Coast63 digital shoreline used by ShoreZone in Alaska poorly resolves features less than 50 meters, i.e., many small scale features are not represented and thus cannot be accurately described; 2) ShoreZone has no explicit minimum or maximum mapping unit resulting in inconsistent placement of unit breaks among mappers; 3) the combination of 1 & 2 contributes to the lack of repeatable unit breaks leading to potential false positive and false negative indications of change at the scale of individual shore units; and 4) users must be cognizant of the limitations imposed by qualitative mapping protocols used prior to the2016 revisions.[26][27][28]