CGRG Bibliography of Canadian Geomorphology
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Author : Forbes, D.L.; Parkes, G.; Manson, G.K.; Ketch, L .; and Solomon, S.M.
Date : 2001.
Title : Shoreline retreat and coastal storms in the southern Gulf of St. Lawrence.
Publication : 2001 AGU Spring Meeting, May 29 - June 2, 2001, Massachusetts, Boston.
Issue :
Page(s) :
Abstract
Submerged fluvial channels and estuarine facies seaward of the sandy North Shore of Prince Edward Island (Canada) attest to long-term mean relative sea-level rise >2.5 mm/a driving coastal retreat at mean rates >0.5 m/a over the past six thousand years. The shoreface, nearshore multiple bar complexes, and beaches are sand-limited and sand is transferred landward into multidecadal to century-scale storage in coastal dune and flood-tidal delta sinks. Stringent quality control of tide-gauge records for Charlottetown (PEI) indicates mean relative sea-level rise of 3.2 mm/a since 1911. When differenced from tidal predictions, this record provides a decadal sequence of storm surge occurrence for comparison with wind, wave hindcast, and sea-ice data for the southern Gulf over the past several decades. Soft photogrammetric digital rectification of vertical air photographs (1935, 1958, 1968, 1980/1981, 1990) and ground surveys (1989-2001) show large spatial and temporal variance in coastal recession rates, poorly correlated with the overall storm record, in part because of wave suppression by sea ice. Retreat of low sandstone-till cliffs at $<$1 m/a shows no statistically significant decadal variance. Other sites with shoreline retreat rates typically between 0.5 and 1.5 m/a show localized acceleration after 1980, reflecting a combination of storm impacts, morphodynamic change and sand loss to adjacent tidal inlets. Individual large storms cause localized rapid erosion, from which recovery depends in part on local sand supply. Some barrier shores with dunes show high longshore and interdecadal variance, and extensive multidecadal healing of former inlet and washover gaps. In some areas, at least, this reflects recovery from an episode of widespread washover predating the 1935 photography.
Bibliography of Canadian Geomorphology