The natural action of waves and wind erodes away beaches. This process is greatly speeded up by human activity, such as removing protective vegetation, dredging, reclaiming land, farming and development. Climate change and rising sea levels also play a part. How you combat coastal beach erosion depends on the severity of the problem, and sometimes, more than one method is needed.
Replanting Native Vegetation
Coastal vegetation, ranging from seaweeds and marsh grasses in the subtidal zone to trees much farther up the beach, naturally prevents erosion. The roots hold the sand and rocks together, stopping them from being blown away or washed out to see. Replanting is the most sustainable and environmentally-friendly way to combat erosion in the long-term.
Physical barriers near the shore are essential when the erosion is expected to be severe. Groynes are usually wooden or concrete structures that reach from the beach straight out to sea, trapping sediment, and slowing down currents.
Unlike groynes, seawalls run parallel along the coast. Seawalls protect the land further inland, although not the beach, from the action of strong waves. They are most commonly made of reinforced concrete or other very tough materials.
Offshore Breakers and Artificial Reefs
Offshore breakers work in a similar way to seawalls by interrupting wave action but just off rather than on the shore. Artificial reefs are submerged breakers. Sometimes they provide temporary protection from wave action until mangroves and marsh grasses grow back. Once the natural vegetation has recovered, offshore breakers are usually no longer necessary.
When a beach has already been seriously eroded, it must be restored by physically replacing the materials lost to the sea. Beach restoration or nourishment involves bringing new sand to a beach by pipes or trucks. It is not a permanent solution and must be periodically redone unless other solutions to erosion are also implemented.
- Food and Agricultural Organization of the United Nations: Protection From Coastal Erosion
- National Oceanic and Atmospheric Administration: Living Shoreline Planning and Implementation
- Texas General Land Office: Coastal Erosion
- U.S. Army Corps of Engineers, Coastal and Hydraulics Laboratory: Seawalls