Preventing Beach Loss
A beach is usually a gently sloped, flat strip of land which lies along either the shoreline of an inland river, lake or ocean or within an inland wetland area. Beach materials such as pebbles, sands, rocks, and other seahells cover many beaches. Most beach materials have been the products of natural erosion and weathering. Beach can also be used to refer to a particular type of sea shore, such as a beach within the territorial waters of a country such as the United States or Canada. The majority of beaches consist of sands that are fine enough to allow swimming but not soft enough to support a strong tide.
Erosion of beaches occurs when the beach moves with the sea, the waves carrying with them whatever they can along to fill in the gap between sand dunes. Sand is very buoyant and adds weight to the beach as it rushes to fill the space between. As a result, the beach may gradually erode away from the sea level as the tide continually pushed against it. When an area of sand has completely disappeared from an ocean floor, it is referred to as a “sea bed”. Other types of erosion include river erosion, continental drift and the folding of sand dunes by wind, ice, or the rising and falling tides.
Ocean currents can also move beaches from their current positions. These movements can sometimes push a beach into an entirely new direction, even perpendicular to its original direction. The amount of current which can move a beach can have an effect on the amount of beach that can be transported to a new location, as well as the strength and speed of the tide which moves across it. Ocean currents do not affect all beaches equally, as certain areas will see stronger or weaker waves depending upon the meridian crossing the beach.
Waves can cause erosion of sandy beaches in many unique ways. The breaking and shifting of waves can carve large holes, exposing the sand beneath and making it more accessible for further movement. The greatest threat to beaches from strong surfacing waves is when the wave overwhelms the beach. The larger the wave, the greater the damage. Wave heights can reach more than six feet when they are coming toward a beach. The break or damage created by a large wave can be compounded or spread over a much larger area than the original area damaged by the wave.
Intertidal zones can sometimes appear on a beach where the surrounding area experiences steep slopes, like those found in many deserts. When the beach appears in a low slope area, it is possible for erosion from the slopes to impact the beach. This is known as the beach berm, and the formation of a beach berm can protect a beach from becoming damaged by waves, edging, and other impacts from the slopes.
Coastal erosion can occur due to the interaction of changing water levels with the slopes. Storm surges, tides, rains, snow storms, and high winds can all cause beach loss. In some cases, estuaries and creeks may be forced into unnatural channels due to rising water levels or other natural factors. In these cases, the beach will lose more sand than the surrounding area, which can add additional burden to beach reclamation projects.