November 5, 2001 GSA Release No. 01-46

Seawall Erosion: Are Some Walls Okay?

Owners of beach property have built seawalls to protect their property from storm damage. But these walls are controversial because they accelerate erosion near the walls themselves. Taking a fresh look at beach survey data collected over eight years in California's Monterey Bay in the vicinity of a seawall has provided geologists with some new insights to the long-term impacts of seawalls on the beach.

"Long-term changes in beach width and volume in front of a seawall that is regularly hit with winter storm waves was not significantly different than the long-term changes measured on adjacent beaches without seawalls," explained James Tait, a geologist at Southern Connecticut State University. Depending on various factors, "a seawall may have no significant long-term effect on beach behavior even though it may cause active erosion during storms. The reasons for this is that rebuilding of the beach during the summer months of fair weather waves allows the beach in front of the wall to recover completely."

Before decisions regarding permitting and construction of seawalls are made, planners need to consider geologic factors such as sediment supply sources, sediment transport rates, and whether or not the beach is presently eroding, e.g., due to sea level rise.

"It is these factors that may determine whether the effects of waves hitting the wall during storms causes net long-term erosion," Tait said.

Tait will present his research on Monday, November 5, at the Geological Society of America's annual meeting, A Geo-Odyssey, in Boston, Massachusetts.

— Written by Kara LeBeau (GSA Staff Writer)
with James Tait

CONTACT INFORMATION

During the GSA Annual Meeting, November 4-8, contact Ann Cairns or Christa Stratton at the GSA Newsroom in the Hynes Convention Center, Boston, Massachusetts, for assistance and to arrange for interviews: (617) 954-3214.

The abstract for this presentation is available at: http://gsa.confex.com/gsa/2001AM/finalprogram/abstract_27491.htm

Post-meeting contact information:

James Tait

Department of Earth Sciences

Southern Connecticut State University

501 Crescent Street

New Haven, CT 06515

E-mail: tait@southernct.edu

Phone: 203-392-5838

Ann Cairns

Director of Communications

Geological Society of America

Phone: 303-357-1056

Fax: 303-357-1074

E-mail: acairns@geosociety.org

For more information about GSA please browse our Web site.

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