Soil Erosion
"Soil erosion (land degradation) is primarily caused by human activity and once started is impossible to reverse." Discuss the validity of this statement drawing on examples from different region worldwide. T he above statement states that soil erosion is impossible to reverse. Personally, I think that there is a solution to almost everything nowadays. Look at how technology is advancing and how information is open to almost anyone. There is a distinction in soil erosion caused by human activity and soil erosion caused by natural processes. To start with, an explanation of 'Soil Erosion'. Basically, soil erosion is the removal of the valuable top layer of soil. If you take a look at the image on the right (topsoil), you can see what is meant with the top layer. As a reader, a possible question might be: why is this top layer of soil so valuable? This top layer is the horizon that contains the vast majority of nutrients and minerals from the decomposing organic matter (humus). These nutrients are recycled between the top soil and the plant matter growing on the surface. While you move down, on the image on the right, you can see subsoil. The further you go down the less nutrients and minerals there are available in the soil and this process is called 'leeching'. Subsequently, I will explain the two different types of naturally-caused soil erosion. The first one is soil
Soil Erosion.
Introduction: Soil erosion is a gradual process that occurs when the actions of water, wind, and other factors eat away and wear down the land, causing the soil to deteriorate or disappear completely. Soil deterioration and low quality of water due to erosion and run off has often become a severe problem around South Africa. Many times the problems become so severe that the land can no longer be cultivated and is abandoned. Problems: > The loss of topsoil reduces the country's soil fertility, hence the ability to grow food. More fertilizers will have to be used as a substitute for the lost soil, therefore a raise in food costs. > The hydrology of river systems is affected, as there is less infiltration and more runoff and therefore reducing the amount of water in the soil for new vegetation to use next season. Seeds struggle to germinate in bare exposed soil. > Dams become silted up and there storage capacity is reduced. > Floods become an increased hazard, because of the increased runoff. Causes: > Overgrazing causes the destruction of plant cover, which would otherwise protect the soil; therefore instead of the rain soaking through the soil, it washes it away. > Ploughing of soil vertically with a slope, increases runoff and accelerates soil erosion. > Destruction of forests is also a major cause, as well as footpaths used for domestic purposes, which turn into
Soil erosion
"The increase in human population to a present day level of over six billion is having an impact on the biosphere that is greater than ever before". The vast amount of impact is greatly due to three major activities including agriculture, industrialization, and urbanisation. Agriculture being one of the major activities contributing to the impact on the biosphere, is the clearing of natural habitat, which most of our ancestors did when they settled in Australia, and consequently without the knowledge of the side effects of clearing forests, cultivating the soil, repeatedly harvesting crops, as well as today's humans who still continue, can lead to dryland salinity and soil erosion, which both accordingly lead to land degradation. Although the seriousness of the agriculture is getting worse, it can be combated. Humans have been obliterating forests all over the world for reasons like, timber, firewood, settlement and agricultural purposes. The benefit for agriculture is almost pointless because the soil in tropical rainforests is of poor nutrients, although the land often becomes productive after a couple of years after the clearing but when there is a limited supply of nutrients in the soil, which is rapidly used up, the crop just declines. Accordingly the farmers leave the land and move onto some where more productive. As a result of this the top soil either washes away or
What is Beach Erosion?
Erosion is the large-scale name for the processes that turn rock into sediment and carry it from high elevations to lower elevations. Erosion is responsible for the shape of the land around us not just things like the Grand Canyon. Erosion is what fills the rivers with silt and piles up the beaches with sand. Erosion is the very reason that streams exist and why the government spends billions of dollars dredging mud from the world's shipping channels. But the main focus of this paper is the persistent eroding of beaches. (Hanley, 1998) What is Beach Erosion? Most people do not know what beach erosion is nor do they care much about it. But erosion has a huge impact on the beach and therefore will affect humans as well. Erosion is the wearing away, or corrosion, by which materials are taken away from the earth's surface. Beach erosion is a global problem that depends and fluctuates depending on the local conditions in a particular area. Erosion has become one of the most alarming threats to regional, national, and international beaches. As humans have built permanent structures on coastlines, coastal protection has become necessary to protect buildings and industry, while preserving features such as beaches and inlets. (Griffin, 1992) What Causes Beach Erosion? Beach erosion is caused by a number of factors. The ubiquitous desire to live near the sea, tropical
Coastal Erosion and Protection.
Geography Homework By Max Hesketh Part 1 – Explain why some coastlines are eroded more quickly than others The main factors that affect the rate of coastal erosion is the geology the coast, direction of the prevailing winds, type of waves surrounding the coast, the coastal management strategy and its likelihood of being prone to sub aerial weathering. All these aspects will determine and test the coastlines overall durability. When situated in a real life situation it becomes clearer to understand why some coastlines erode faster than others. For example, the geology the happisburgh coast is very weak, as it includes sandstone layered onto clay. As sandstone is permeable, rainfall infiltrates it, adding weight to the cliff and lubricating it. A slip lane is created. Soon after the sandstone moves and collapses of the clay and ultimately crumbles the cliff. However, other factors cause erosion. Prevailing winds are also a vital asset on natures behalf as they control the direction of the waves, which are needed to erode a shoreline. Happisburgh's prevailing winds are being blown from the Antarctic, which are harsh, fierce winds which therefore ensures the wave type to be destructive. This is an example of how a coastline can erode quicker than others. Part 2 – My view on: 'The British coastline should be better protected
Sediment Mobilization Coastal Erosion.
Sediment Mobilization Coastal Erosion Coastal erosion occurs when sediments from upstream fail to replenish shore sediments. The latter are constantly eroded by wave action and, thus, coast lines undergo dramatic change. Reduction of sediments is primarily due to the construction of structures for hydrological modifications and diversions, in particular dams. The effect of dams on the relative ecology of an area is a subject which has been studied in detail. This is due to the dramatic consequences seen in all rivers once large-scale dams have been constructed. Given below is a detailed account of the effects of dams on aquatic habitats. Dams are constructed for various reasons and very few are built for a single purpose. Agriculture may be viewed as a primary factor, however, as it is responsible for the majority of water abstracted from reservoirs created by dam construction. The effect of damming a waterway is to effectively halt the transport of sediment from upstream of the dam as it settles within the reservoir. This sediment accumulation has a negative effect on the reservoir as over time it dramatically reduces the volume of water that can be stored, thereby reducing the dam's effectiveness. The 'flushing' of sediments from the dam sometimes controls this but can result in a sudden flush of anoxic water and sediments with detrimental results as they smother
Managing coastal erosion, Holderness
Coasts-Case studies Managing coastal erosion, Holderness The Holderness coast lies between Flamborough Head and Spurn Head and is one of the fastest eroding coastlines in Europe. The average rate of erosion is 2 metres per year. Over 30 villages and 26 towns have fallen into the sea since roman times. There are lots of erosion features along the Holderness coast. The coastline is made of soft clay which experiences rapid erosion. In addition, longshore drift moves south along the coastline so there is little opportunity for beaches to become established in front of the cliffs The erosional landforms evident along the coastline are varied. There is a wave-cut notch and a wave cut platform at Flamborough Head. Flamborough Head is a headland and along the same coastline are caves, arches and stacks. Towns and villages are constantly under threat from the sea. The coast needs to be managed to protect the settlements. During the cource Hornsea Hornsea is a town on the Holderness coastline that has nearly 3km of shoreline fronting the town. The coastline's position has been fixed since the coastal defences were put up which was in 1990s. A concrete sea wall protects the town from flooding. Groynes ensure that the sand and shingle beach is not washed away by long shore drift. Mappleton Mappleton is a village 3km south of Hornsea. The village has been exposed to rapid
Swanage and Coastal Erosion
Sketch Map of Swanage showing Coastal Features Coastal Erosion A coast is a long narrow zone where land and sea meet. The sea erodes the coast in four ways: * Hydraulic Action Lots of sea and water crashes against the land, and air and water are trapped and compressed in rock surface cracks. When the sea moves again the air expands explosivel weakening the rocks, enlarging the cracks and breaking pieces off. * Corrasion (abrasion) This is very effective and is caused by brocken rock fragments hitting the land, cliffs etc.. and breaking off other pieces of rocks. * Attrition This occurs when rock fragments grind against each other down into smaller and smoother pebbles and shingle and finally sand which is later deposited as beaches etc... * Corrosion This involves chemical action of sea on rock. If the rock is limestone, it dissolves in the sea water - some salts can also react with certain rocks and cause them to rot. Swanage Bay Swanage Bay is made up of a less dense rock called clay. For this feature it is wealden clay. Swanage Bay can be found between 043,787 and 047,812 on the map. This type of rock is non-permeable therefore it is easily eroded. Wave refraction, deposition and corrosion forms bays. Deposition is when sediments such and sand and shingle are washes onto the shore. If there are alternate bands of hard and softer rocks in the coastline, the
Erosion, Weathering, and Mass Movement
Erosion, Weathering, and Mass Movement Erosion is the break-down of rock and transportation of this material away. Weathering is a form of erosion involving elements of the weather, e.g. chemical weathering like corrosion of limestone, and mechanical weathering like exfoliation in deserts and freeze thaw (frost shattering) in colder areas. MASS MOVEMENT When large amounts of rock become unstable they will collapse. The contributing factors are rock type and excess water. (a) Slumping - large amount of rock will collapse along a line of weakness if the ground is saturated. (b) Land-slide - unstable rock collapses (usually in sections) (c) Rotational slip - rock slides along a slip
Pre-modern causes of erosion theories.
Erosion of the Sphinx The Sphinx was created by carving it from a single block of bedrock limestone measuring at 73 meters long by 20 meters high. The dates to witch archeologists determine the age of the monument to be is a mystery. Some suggest that the sphinx was crafted in the 4th dynasty while others think it was under repair during that time. It is even suggested that the sphinx was created before human kind walked the earth. The date that the sphinx was sculpted plays a very large role to determine the types of erosion to occur on the sphinx. This is due to the fact that different periods of time, different climates existed. This difference in humidity and temperature could lead to an increase in either mechanical or chemical weathering or any one particular type of weathering to take place. Pre-modern causes of erosion theories Sand: Almost all of the theories as to how the sphinx was eroded have reference to sand being a contributing factor. This is mainly due to that most archeologists agree that most of the sphinxes life, it has been covered in sand. Also sand has been around the sphinx for almost all of its life increasing the chance of sand being picked up and thrown into the sphinx by the wind. Ground water erosion: From looking at the paws of the Sphinx archeologists believe that ground water caused some erosion to the sphinx. A theory was proposed that
