Erosive water level regime and climatic variability forcing of beach-dune systems on south-western Vancouver Island, British Columbia, Canada

Derek K. Heathfield, Ian Walker, David E. Atkinson

Research output: Contribution to journalArticle

13 Citations (Scopus)

Abstract

Increases in the frequency and magnitude of extreme water levels and storm surges are correlated with known indices of climatic variability (CV), including the El Niño Southern Oscillation (ENSO) and the Pacific Decadal Oscillation (PDO), along some areas of the British Columbia coast. Since a shift to a positive PDO regime in 1977, the effects of ENSO events have been more frequent, persistent, and intense. Teleconnected impacts include more frequent storms, higher surges, and enhanced coastal erosion. The response of oceanographic forcing mechanisms (i.e. tide, surge, wave height, wave period) to CV events and their role in coastal erosion remain unclear, particularly in western Canada. As a first step in exploring the interactions between ocean-atmosphere forcing and beach-dune responses, this paper assembles the historic erosive total water level (TWL) regime and explores relations with observed high magnitude storms that have occurred in the Tofino-Ucluelet region (Wickaninnish Bay) on the west coast of Vancouver Island, British Columbia, Canada. Extreme events where TWL exceeded an erosional threshold (i.e. elevation of the beach-foredune junction) of 5·5m aCD are examined to identify dominant forcing mechanisms and to classify a regime that describes erosive events driven principally by wave conditions (61·5%), followed by surge (21·8%), and tidal (16·7%) effects. Furthermore, teleconnections between regional CV phenomena, extreme storm events and, by association, coastal erosion, are explored. Despite regional sea level rise (eustatic and steric), rapid crustal uplift rates have resulted in a falling relative sea level and, in some sedimentary systems, shoreline progradation at rates approaching +1·5m a-1 over recent decades. Foredune erosion occurs locally with a recurrence interval of approximately 1·53years followed by rapid rebuilding due to high onshore sand supply and often in the presence of large woody debris and rapidly colonizing vegetation in the backshore.

Original languageEnglish (US)
Pages (from-to)751-762
Number of pages12
JournalEarth Surface Processes and Landforms
Volume38
Issue number7
DOIs
StatePublished - Jun 15 2013
Externally publishedYes

Fingerprint

coastal erosion
dune
Pacific Decadal Oscillation
water level
beach
Southern Oscillation
regime
Canada
erosion
water
event
woody debris
recurrence interval
coast
teleconnection
storm surge
progradation
extreme event
wave height
shoreline

Keywords

  • Beach
  • Climatic variability
  • Coastal erosion
  • El Niño Southern Oscillation (ENSO)
  • Environmental forcing
  • Foredune
  • Pacific Decadal Oscillation (PDO)

ASJC Scopus subject areas

  • Earth and Planetary Sciences (miscellaneous)
  • Earth-Surface Processes
  • Geography, Planning and Development

Cite this

Erosive water level regime and climatic variability forcing of beach-dune systems on south-western Vancouver Island, British Columbia, Canada. / Heathfield, Derek K.; Walker, Ian; Atkinson, David E.

In: Earth Surface Processes and Landforms, Vol. 38, No. 7, 15.06.2013, p. 751-762.

Research output: Contribution to journalArticle

@article{9dfca59c5cdb40978738b6d14dbc32dc,
title = "Erosive water level regime and climatic variability forcing of beach-dune systems on south-western Vancouver Island, British Columbia, Canada",
abstract = "Increases in the frequency and magnitude of extreme water levels and storm surges are correlated with known indices of climatic variability (CV), including the El Ni{\~n}o Southern Oscillation (ENSO) and the Pacific Decadal Oscillation (PDO), along some areas of the British Columbia coast. Since a shift to a positive PDO regime in 1977, the effects of ENSO events have been more frequent, persistent, and intense. Teleconnected impacts include more frequent storms, higher surges, and enhanced coastal erosion. The response of oceanographic forcing mechanisms (i.e. tide, surge, wave height, wave period) to CV events and their role in coastal erosion remain unclear, particularly in western Canada. As a first step in exploring the interactions between ocean-atmosphere forcing and beach-dune responses, this paper assembles the historic erosive total water level (TWL) regime and explores relations with observed high magnitude storms that have occurred in the Tofino-Ucluelet region (Wickaninnish Bay) on the west coast of Vancouver Island, British Columbia, Canada. Extreme events where TWL exceeded an erosional threshold (i.e. elevation of the beach-foredune junction) of 5·5m aCD are examined to identify dominant forcing mechanisms and to classify a regime that describes erosive events driven principally by wave conditions (61·5{\%}), followed by surge (21·8{\%}), and tidal (16·7{\%}) effects. Furthermore, teleconnections between regional CV phenomena, extreme storm events and, by association, coastal erosion, are explored. Despite regional sea level rise (eustatic and steric), rapid crustal uplift rates have resulted in a falling relative sea level and, in some sedimentary systems, shoreline progradation at rates approaching +1·5m a-1 over recent decades. Foredune erosion occurs locally with a recurrence interval of approximately 1·53years followed by rapid rebuilding due to high onshore sand supply and often in the presence of large woody debris and rapidly colonizing vegetation in the backshore.",
keywords = "Beach, Climatic variability, Coastal erosion, El Ni{\~n}o Southern Oscillation (ENSO), Environmental forcing, Foredune, Pacific Decadal Oscillation (PDO)",
author = "Heathfield, {Derek K.} and Ian Walker and Atkinson, {David E.}",
year = "2013",
month = "6",
day = "15",
doi = "10.1002/esp.3350",
language = "English (US)",
volume = "38",
pages = "751--762",
journal = "Earth Surface Processes and Landforms",
issn = "0197-9337",
publisher = "John Wiley and Sons Ltd",
number = "7",

}

TY - JOUR

T1 - Erosive water level regime and climatic variability forcing of beach-dune systems on south-western Vancouver Island, British Columbia, Canada

AU - Heathfield, Derek K.

AU - Walker, Ian

AU - Atkinson, David E.

PY - 2013/6/15

Y1 - 2013/6/15

N2 - Increases in the frequency and magnitude of extreme water levels and storm surges are correlated with known indices of climatic variability (CV), including the El Niño Southern Oscillation (ENSO) and the Pacific Decadal Oscillation (PDO), along some areas of the British Columbia coast. Since a shift to a positive PDO regime in 1977, the effects of ENSO events have been more frequent, persistent, and intense. Teleconnected impacts include more frequent storms, higher surges, and enhanced coastal erosion. The response of oceanographic forcing mechanisms (i.e. tide, surge, wave height, wave period) to CV events and their role in coastal erosion remain unclear, particularly in western Canada. As a first step in exploring the interactions between ocean-atmosphere forcing and beach-dune responses, this paper assembles the historic erosive total water level (TWL) regime and explores relations with observed high magnitude storms that have occurred in the Tofino-Ucluelet region (Wickaninnish Bay) on the west coast of Vancouver Island, British Columbia, Canada. Extreme events where TWL exceeded an erosional threshold (i.e. elevation of the beach-foredune junction) of 5·5m aCD are examined to identify dominant forcing mechanisms and to classify a regime that describes erosive events driven principally by wave conditions (61·5%), followed by surge (21·8%), and tidal (16·7%) effects. Furthermore, teleconnections between regional CV phenomena, extreme storm events and, by association, coastal erosion, are explored. Despite regional sea level rise (eustatic and steric), rapid crustal uplift rates have resulted in a falling relative sea level and, in some sedimentary systems, shoreline progradation at rates approaching +1·5m a-1 over recent decades. Foredune erosion occurs locally with a recurrence interval of approximately 1·53years followed by rapid rebuilding due to high onshore sand supply and often in the presence of large woody debris and rapidly colonizing vegetation in the backshore.

AB - Increases in the frequency and magnitude of extreme water levels and storm surges are correlated with known indices of climatic variability (CV), including the El Niño Southern Oscillation (ENSO) and the Pacific Decadal Oscillation (PDO), along some areas of the British Columbia coast. Since a shift to a positive PDO regime in 1977, the effects of ENSO events have been more frequent, persistent, and intense. Teleconnected impacts include more frequent storms, higher surges, and enhanced coastal erosion. The response of oceanographic forcing mechanisms (i.e. tide, surge, wave height, wave period) to CV events and their role in coastal erosion remain unclear, particularly in western Canada. As a first step in exploring the interactions between ocean-atmosphere forcing and beach-dune responses, this paper assembles the historic erosive total water level (TWL) regime and explores relations with observed high magnitude storms that have occurred in the Tofino-Ucluelet region (Wickaninnish Bay) on the west coast of Vancouver Island, British Columbia, Canada. Extreme events where TWL exceeded an erosional threshold (i.e. elevation of the beach-foredune junction) of 5·5m aCD are examined to identify dominant forcing mechanisms and to classify a regime that describes erosive events driven principally by wave conditions (61·5%), followed by surge (21·8%), and tidal (16·7%) effects. Furthermore, teleconnections between regional CV phenomena, extreme storm events and, by association, coastal erosion, are explored. Despite regional sea level rise (eustatic and steric), rapid crustal uplift rates have resulted in a falling relative sea level and, in some sedimentary systems, shoreline progradation at rates approaching +1·5m a-1 over recent decades. Foredune erosion occurs locally with a recurrence interval of approximately 1·53years followed by rapid rebuilding due to high onshore sand supply and often in the presence of large woody debris and rapidly colonizing vegetation in the backshore.

KW - Beach

KW - Climatic variability

KW - Coastal erosion

KW - El Niño Southern Oscillation (ENSO)

KW - Environmental forcing

KW - Foredune

KW - Pacific Decadal Oscillation (PDO)

UR - http://www.scopus.com/inward/record.url?scp=84878850950&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84878850950&partnerID=8YFLogxK

U2 - 10.1002/esp.3350

DO - 10.1002/esp.3350

M3 - Article

AN - SCOPUS:84878850950

VL - 38

SP - 751

EP - 762

JO - Earth Surface Processes and Landforms

JF - Earth Surface Processes and Landforms

SN - 0197-9337

IS - 7

ER -