The High Water Line as Shoreline Indicator

摘要: Beach erosion rates are often determined by delineating historical shoreline positions from maps and aerial photographs more recently global positioning systems (GPS). The high water line is usually selected as the indicator for mapping purposes; it defined wet ted bound "markings left on beach last tide." that acquired field determination or photogrammetric means assumed to represent mean position year, but studies have shown its variable because of changes in level due waves, wind, tides, other factors. This study investigated short-term variability location over tidal cycles, days, months through observations interpretation videotape data. Studies, undertaken at Assateague Island National Seashore Maryland Field Research Facility Duck, North Carolina, indicated a useful within certain limits. GPS shorelines based actual identification deemed accurate than photo-interpreted coastal management.