How Natural Processes Operate at Coastal Geographic Environment

Any rainfall increases fluvial erosion. When rain does fall, this creates ephemeral streams causing water erosion due to fast forces of water. Flash floods are possible as well creating even more erosion.

Wind and waves affect Glenelg as they set up a northward drift of sand along the coast and this type of sand movement is known as littoral drift. During coastal storms, huge quantities of sand are eroded and this does damage to near shore, beach and sand dune areas. Glenelg is not considered to be a stable as beach as many others are. Seagrass loss and seabed instability that affect Glenelg is that a third of seagrass meadows along the coasts of Glenelg has died since 1950 and poor water quality resulting from the stormwater runoff and effluent disposal has most likely been the initial cause. When there are gaps in the seagrass meadows the sand below the meadow edge can be eroded by the waves and this will in turn increase the rate of seagrass loss and make it difficult for plants to recolonise the seafloor, even though the water quality has been improved. Sea levels affect Glenelg as parts of Glenelg are being subsided as a result of climate change and a relative sea level rise of one to two millimetres per year has been recorded for Glenelg. “As a result of the loss of sand from the seabed, the level of the seabed has steadily become up to one metre deeper and the wave energy reaching our beaches has increased.” (Adelaide’s Living Beaches Strategies,

Sand nourishment refers to the replacement of sediment on beaches that has previously been lost, generally through natural processes. It is a commonly used practice in coastal management. Collaroy Beach uses sand nourishment as longshore drift has moved sand, which cannot be replenished as there are rock formations preventing sediment from refilling the beach. Collaroy Beach also does not have an established dune system, and cannot trap sand.

Beach nourishment is the physical transfer of sand from an area of excess to where it is being eroded. This often involves dredging and transport of sand by truck or through pipeline. Because of the cost involved, beach nourishment is only used where other strategies prove to be ineffective.

* The Skillion, mainly the headland and rock platform, which is part of a preserved area of land known as “the Haven” which also contains the rugby oval. The man type of erosion that affects this is from the sea.

Longshore drift is movement of sediment along the coastline. The prevailing wind blows waves carrying sediment into the beach at an angle, the waves break on the shore and as the water runs back into the sea it carries the sediment back down the beach, perpendicular to the angle. This will lead to a zigzag motion (/\/\/\/\/) as

tides. There are also many programs which help to ensure the stabilization of dunes, these include the planting of new vegetation to combat erosion, fencing and designated

There are six different types of water erosion: splash erosion, sheet erosion, rill erosion, gully erosion, valley or stream erosion, and bank erosion. Splash erosion is when raindrops hit soil and small soil particles are displaced. Sheet erosion is when raindrops remove soil in thin layers. During rill erosion, small concentrated flow paths are created. “These paths create a sediment source and delivery system for hillslope erosion. Areas where precipitation rates exceed soil infiltration rates are more prone to this type of erosion. During gully erosion, water flows in narrow channels during or after heavy rains or melting snow. The gullies can erode to considerable depths. Valley or stream erosion is created by water flowing alongside land. It extends downward, deepening a valley, and extending the valley into the hillside. This occurs more frequently

Long Island is famous for its sandy ocean beaches. Between the barrier beach and the main coast is the Great South Bay. The beaches and dunes have very different characteristics. The sandy beach is the junction of land and ocean. The sandy beach consists of two zones, the swash zone and the drift line. The swash zone is the area of wet sand, caused by the incoming wave. The drift line is formed by the dead seaweed and other aquatic plants. Behind the sandy beach is the primary dune. The primary dune's main function is to absorb the force of the ocean and protect the great south bay and the island's main coast. In some cases secondary dunes form. These dunes are behind the primary dune and are therefor protected from the ocean. This provides the stability necessary for plant growth. Many time a maritime forests will form on secondary dunes.

Thusly, chronic coastal erosion is beginning to become a huge problem along a majority of the U.S. coast, exclusively on Hawaiian Islands (Romine and Fletcher, 2013). “Kona” storms, with southerly winds and waves, can trigger momentary erosional events to south and west exposed beaches on the coast (Romine and Fletcher, 2013). Erosional events are undoubtedly proving to control most shoreline changes throughout the state Hawaii, let alone Kauai. Romine and Fletcher’s studies of historical shorelines on major Hawaiian Islands, including Kauai, have proven that shoreline changes on the islands are displaying a dominant trend of being caused by erosion (2013) on the leeward and windward sides of the

8. What are different ways that earth materials are moved around in the oceans? Surf is a powerful force. It causes erosion and moves sediment from one location to another. Currents are another manner in which materials are transported through the ocean system. There is a longshore current and a beach drift responsible for disturbing and transporting materials.

In coastal flooding the coastal areas are flooded due to storm activity at sea. The waves break through coastal defenses and submerge the area.

It is this soft sand and clay which is easily eroded by the action of waves, as the ocean slowly claims back the region it used to occupy. There are

Runoff and Pollution: Storm generated precipitation can rapidly dilute ocean water and runoff can carry pollution bleaching near-shores corals.

The Effects of Human Activity on Coastal Landforms Human activities add another layer of complexity to the natural processes of coastal lands and materials. These activities may have direct or indirect effects on our changing coastlines. They may effect sources of new sediment to the coast and the movement of sediment within the coastal environment. Sediment starvation caused by river and coastal management is one effect of human activities on the coast. For some coastal regions, such as the Pacific coast, a large part of their sediment is supplied by rivers.