The Evolution of Beaches

Beach Formation

• To understand beach evolution, it's important first to know how beaches originally form. Over time, waves and tides interact with the earth at the shoreline, both above and below the waterline. The constant movement of this water breaks up this earth. It also breaks up shells and coral located near the coast.

  The fragments and particles that result combine and form sand. Coarser fragments end up settling closer to the coast, while fine pieces wash out and settle further away from shore. This sand settles on bedrock that slopes down and away from the coast. When enough sand settles, a beach forms.

Beach Erosion

• Beach erosion diminishes coastlines over time. Typically, when it erodes a beach and it disappears, it is gone for good. This is a natural process that occurs across the globe but hits some places harder than others. Louisiana, for example, is one of the places hardest hit by beach erosion. The state loses about 50 feet of beach every year. Other places may only lose a few inches or fewer. Global warming, which causes a rise in sea levels, could result in the quicker erosion of beaches.

Severe Storm Erosion

• While casual beach erosion is episodic and usually slow (Louisiana being an exception to the rule). a beach can be radically reshaped over a short period of time. This occurs during major coastal storms, like hurricanes or tsunamis. Hurricane Andrew, in 1992, drastically overwhelmed and altered the beaches in Florida and Louisiana. Trinity Island in Louisiana, for example, had such severe beach erosion that it unearthed old pier pilings covered by beach sands in the process.

Beach Nourishment

• The best example of human interaction that evolves beaches is through beach nourishment. This is a process that involves dredging up sand elsewhere offshore and dumping it onto existing beaches to add to the existing stretch of beach or to replace what was lost through natural erosion processes. Beach nourishment can protect structures, located just behind the beach, from constant erosion effects and restore recreational beaches but it can affect the local environment by radically changing the geography of the land.