Coastal erosion may be a rapid process wherever the coastline consists of
unconsolidated material, and is a geological hazard when development occurs as well.
Coastal erosion commonly involves the destabilization of cliffs following wave
impact during storms, but may also include ground- or surface-water effects
from development adjacent to the coast.
| Active Coastal Erosion.
The images above show the active erosion of a beach and embankment
along the shores of Chamberlains, Conception Bay. They were taken shortly
before and after a series of storms in 1992.
Both images reproduced by permission of Martin Goebel © 1992.
Point Verde consists of a gravel peninsula at the entrance to Placentia Road,
southwest of Placentia, Avalon Peninsula. The peninsula protects Placentia from
some of the effects of major storms, and hosts a few houses, a gravel-pit operation,
and a light station. The peninsula is joined to the mainland by barrier beaches. The
sea cliff is eroding at a rate estimated between 0.5 and 2 m/year, based on aerial
photograph analysis and monitoring sites. Several structures relating to the
light-station have been lost. Further cliff erosion combined with extraction of
gravel may result in the loss of the gravel-pit operation, and increase the flood
risk in the communities of Point Verde and Placentia.
Kippens-Port au Port East
The stretch of coast lying between Stephenville and the Port au Port Peninsula
has seen increased development in the last few years. The coastline in this area
consists of steep (up to 30 m) cliffs of sand and gravel that are retreating at an
unknown rate. Encroachment of house construction into the cliff edge area has
resulted in increasing concerns regarding property loss. The provincial
Geological Survey has visited the site in recent years at the request of the local
council. The Atlantic Geoscience Centre of the Geological Survey of Canada
contracted a detailed photogrammetric survey of this area to evaluate erosion rates.
Following a period of heavy rain in May 1994 rapid forward expansion of a gully
occurred at Port au Port East.
|Eroding Coastal Cliffs.
Landslide in coastal cliffs at Port au Port East that occurred in May 1994.
Reproduced by permission of Martin Batterson © 1994.
information (38 kb).
The slide area measured about 150 by 200 by
30 m, and ended about 50 m from the nearest structure. A large debris fan was formed
on the beach. Two smaller failures also occurred during the same storm, 500 m and
1300 m west of the main failure.
Images and text reproduced by permission of M. Batterson, D.G.E.
Liverman, J. Ryan and D. Taylor, The Assessment of Geological Hazards
and Disasters in Newfoundland: An Update. (St. John's: Government of
Newfoundland and Labrador, Department of Mines and Energy, Geological
Survey, © 1999) unless otherwise noted.