How Natural Processes Operate at Coastal Geographic Environment
Natural Processes are actions or events that have natural causes, which result in natural events. The three main coastal environment processes that operate at Muriwai are Coastal Erosion, Coastal Transportation and Coastal Deposition.
The elements that interact to produce natural processes are wind, waves and tides. Each phenomenon at Muriwai's coastal geographic environment has been produced by interaction.
Coastal Erosion is a process at Muriwai that gradually wears away the rock particles of the earth's surface, transporting them to another location. There are many types of processes that cause erosion at Muriwai such as wave erosion, wind erosion and wave refraction.
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These types of erosion have caused the formation of several phenomena at Muriwai.
Motutara Island (stack) was produced by the formation of two caves on either side of the headland -- forming an arch and the roof slowly eroding away due to vertical erosion.
Fisherman's Rock was produced by cliff retreat when undercutting stones are thrust at the cliff by wave action.
The blowhole was formed by vertical, hydraulic and mechanical erosion causing the cracks and fissures to enlarge over time to produce this hole.
Types of wave erosion operating on the headland have produced the cave.
Wave Refraction is an important process as it influences wave erosion on Otakamiro headland and on the beach at Muriwai (refer to Diagram 1). Wave Transportation (Longshore Drift) varies spatially due to wave refraction. It is the process by which waves alter their course as they interact in shallow water with the seabed along the coastline. This process produces wave erosion, which focuses its energy on Otakamiro Point.
Diagram 1
Constructive, Destructive and Dissipative are the types of waves that operate at Muriwai that cause erosion.
Dissipative waves are the waves usually found at Muriwai -- they lose their energy before they reach the shore as they usually break on the offshore bar. Constructive waves are long waves with little height that leave material at the top of the beach, building it up.
Destructive waves are erosive
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
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.
At Nudgee Beach, erosion was found to have occurred on the edges of the mangrove forest and along the mudflat shorelines. Erosion is typically influenced by natural factors and occurs when pieces of weathered rock or soil are moved – typically by wind and water – from one place to another. Shorelines with lots of sediment and sand are more inclined to be effected by erosional progression. Erosion may also be provoked and accelerated by human interference. For example, if the decision to clear trees and plants from an area is made, erosion is likely to occur as the root systems of plants work to hold the soil in place. If these root systems are removed and erosion does occur, environmental conditions – such as; landslides and flooding – are more likely to take place. Erosion may also cause other plants to tip over, have their underground roots exposed and damaged and contribute to the pollution of local waters; as a result of mud and soil runoff [26]. Erosion at Nudgee Beach was likely to have been influenced by natural factors; however, the development and extension of the Kedron Brook golfing course may contribute to the acceleration of erosional processes and further damage the mangrove
period of time have increased the size of the beach. Enviromental organisations have tried there best to limit the amount of man made deveoplment on coastal lads and many schools
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
The erosion of shorelines is a natural process that can have beneficial or adverse impacts on the creation and maintenance of habitats. Sands and gravels eroded from the shores of coastal bays maintain the beach as a natural barrier between the open water and coastal wetlands. Beaches move back and forth onshore, offshore and along shore with changing wave conditions. The finer-grained silts and clays derived from the erosion of shorelines are sorted and carried as far as the waters of wetlands or tidal flats, where benefits are derived from addition of the new material. However, excessively high sediment loads can smother submerged aquatic vegetation beds, cover shellfish beds and tidal flats, fill in riffle
Erosion is mainly caused by two main natural forces: water and wind. In Southwest Louisiana, erosion by water is one of the main issues we have as a coastal state. There are different factors that must be considered when looking at water erosion
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 the upper corer of the topo map, it shows the same feature that was observed in figure 6, figure 7 and figure 8, where the ancient shoreline of the Salton Sea once resided. Southwest of the topo map is shows contours lines evenly space-out and directional flow of small channels which is evident of flash flooding. So, that area is a flood plain or a sheet flow that has eroded the base of the alluvial fan. The alluvial fan is very distinctive in the topo map where the active channel flows downstream through a laterally confined mountainous valley that cuts through the alluvial fan, ancient shoreline and bleeds to a non-confined lowland of the flood
meters of vertical loss. Waves than eroded the face of the dunes that caused dune
In our society education is so often overlooked; children sometimes don’t want to go to school and almost everyone has the opportunity to get a proper education. But as shown in Parvana education in Afghanistan is controlled and oppressed, only to be taught to some members of society and even then it is only taught in a way that the Taliban sees fit. In the book Parvana, she reads letters to people who are unable to for themselves, her father gets dragged away for having a foreign education and they banned education for girls. Because of all this the Taliban have been able to control their society easily.
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.
The wave normals were closer at the rocky point, indicating that wave energy was higher in that location. If we take into account only wave energy, this location should have the highest rate of erosion. The difference between the wave normals in the idealized rocky point and the wave normals in the field is the direction of the approaching waves. In the field, the waves were approached the coastline at an angle from the south. In the idealized rocky point, the waves direction of approach is parallel to the coastline. As a result, the wave normals in the field had a greater curvature in the left side than in the right side.
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The weather also has a large influence. Often there are winter storm surges producing higher waves, and higher sea levels, meaning higher energy erosion. In addition is increased sub-aerial denudation brought about by the heavy rain and strong winds. This often leads to increased slumping and