Coastal Engineering
Beach Protection

Seawalls, revetments and groins are generally used to protect valuable waterfront property from the water's erosive powers. There are millions of kilometres of shorelines, rivers and streams in the world. These areas have great economic, social, and environmental value providing recreational areas, transportation, and habitats for aquatic and land plants and animals.

Seawalls and revetments normally run parallel to the shoreline.

The classical "hard engineered" shore protection solutions use stone, concrete, and steel sheet pile facings and retaining walls.

Earth filled beach protection - France

Stone beach protection - Tel Aviv

Masonry seawall used as beach protection along the Rhine, France
Concrete beach protection - Hong Kong

Concrete seawall used to protect a parking lot and a small marina on Maui.

Lava rock seawall protecting the town of Lahaina, Maui.

Use of lava rock to protect the shore on Maui.

Beach protection at Hilo, Hawaii - this breakwater was credited for decreasing the damage caused by a tsunami in the early 1960's.

Revetments

The hamlet of Runswick Bay before construction. The old seawall in front of the parking lot was sliding into the sea. There was a fear of an avalanche occurring.

Disaster Given the Slip: 11/11/1999 issue of the New Civil Engineer

photos scanned, with permission from NCE

A rock armour revetment now replaces the seawall. The hillside was stabilized and the high pressure groundwater flows relieved.

Groins are low rubble-mound structures oriented roughly perpendicular to shore to protect against erosion by trapping sediment.


Unfortunately studies are now showing that classical "hard engineered" shore protections like these are causing significant damage to the natural habitats of both plants and animals. Civil engineers are now starting to study and implement natural or bioengineered shore protection techniques. Soil bioengineering uses living plants and other organic products to help stabilize the banks and control erosion. This also helps to enhance habitats and to purify and filter the overland runoff.

Submerged wave filters may be used as artificial reefs for coastal protection. They are invisible from the shore, make it possible for water to circulate, require less space than the old traditional "hard" shore protection and have a wide operating range.


Associated Sites:

Canadian Hydraulic Centre

    

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