A beach is a narrow gently sloping strip of land that borders a body of water. It can be made of sand, rocks, cobbles, pebbles or shells. They vary in size and shape, depending on the wave conditions and materials. Some beaches have man-made structures such as shacks or changing rooms. Alternatively, they may be protected by seawalls.
Besides wind and waves, ocean currents play a big part in shaping a beach. They transport sediment and other debris along the coastline and out to sea. The material accumulates on the beach during periods of accretion. These periods of accumulation can last several years. Ocean currents carry sediment hundreds of kilometers from the coast. This means that beach beds can be changed every day.
During storm seasons, wave energy is increased, and the period between breaking waves is shorter. This increases the number of fine-grained sand particles that travel offshore. At the same time, the average height of waves is higher on the beach. This enables the waves to move the fine-grained material up the beach more quickly, into deeper waters. In addition, the water is turbid, increasing the density of the particles and the fluid’s erosive power.
During periods of erosion, the beach is swept away by the waves. This process can lead to the collapse of the overburden and the destruction of flora and fauna. For example, if a large sand crab population has been displaced, it will not repopulate the beach until the following year. The sand crab larvae may drift with the ocean currents for a year or two before returning to the beach. However, the beach will be less eroded if the sediment is compacted.
Beaches can be quite long, extending hundreds of kilometers. In addition, they can be wide or narrow. While the beach is not stable, it can be easily modified by man-made structures such as seawalls. Seawalls can be built of concrete or rock.
If a beach is eroded by a high-wind event, it may expose the less resistant soils. It could also introduce foreign flora and fauna. Additionally, unwashed sediments, such as sewage and toxic chemicals, may cause problems for humans. To keep the beach clean, visitors should never throw anything into the ocean or leave trash on the beach.
Depending on the beach’s geographic location, it can be flooded during a major storm. This is especially true in tropical regions. Sediment can also be washed into the ocean from swamps and rivers. Eventually, this waste may wash out to sea and become hazardous for humans. So, to prevent the destruction of beaches, it is important to monitor pollution.
On the other hand, if the beach is protected from coastal erosion, it can be a great recreational area. Many sandy beaches are home to hotels and lifeguard posts, and offer changing rooms. But a beach can be polluted by sewage, toxic chemicals, and other debris. Not only do these wastes harm wildlife, but they can also destroy beaches.