Examine the factors influencing the movement of glaciers.
Examine the factors influencing the movement of glaciers. Glacier is defined as, 'a mass or river of ice moving very slowly'. Glaciers range in size considerably, Antarctica being the largest ice mass at 12.5 million km and a smaller ice mass of 12km existing in Africa. Glaciers move due to the force of gravity from areas of high altitude to lower areas. There are different mechanisms of glacial movement depending on the type of glacier. Cold (polar) glaciers are frozen to the underlying rock surface. These are found in high-latitude locations where the relief is low and basal temperatures are below the pressure melting point. Cold glaciers have very slow rates of movement, e.g. The Meserve glacier in Antarctica moves only 3-4 metres per year. Warm (temperate) glaciers on the other hand are not frozen to their bed. This type of glacier is found in high-altitude locations where the relief is steep and basal temperatures are at or near the pressure melting point. Temperate glaciers move very rapidly, e.g. The Franz Josef glacier in New Zealand moves approximately 300m per year. It is the basal temperature that determines the mechanism of movement. In what follows I will explain the factors influencing different mechanisms of movement. Temperate glaciers move mainly by basal sliding. If the basal temperature is at or above pressure melting point, a thin layer of meltwater
Explain where and why depositional landforms occur along the course of a river.
Explain where and why depositional landforms occur along the course of a river. Rivers have three courses. The course is the journey the river makes to reach the sea. Rivers never have a straight course from source to mouth. Their course is always irregular. Along this course depositional landforms can occur. Landforms can be formed from the deposition of weathered and eroded surface materials. On occasion, these deposits can be compressed, altered by pressure, heat and chemical processes to become sedimentary rocks. This includes landforms with some of the following geomorphic features: beaches, deltas, floodplains, and glacial moraines. The upper course is found in the mountains and hills where the river rises from its source and often waterfalls and rapids are also found in this course. The river is usually fast flowing in the upper course; also there are lots of stones and boulders for the water to flow over. Furthermore, the river starts as a stream in the upper course and flows through valleys. The middle course, however, is where the river starts to become wider and deeper. The land, which the river flows over, is becoming flatter and this is where the river starts to meander or bend in the middle course. The lower course is where the river becomes its widest and deepest. This course is found closest to the sea where the river has its mouth. The flat area of land by
Discus to the extent to which you believe Carlisle floods 2005 were the result of intense rainfall rather than the physical characteristics of the drainage basin
Discus to the extent to which you believe Carlisle floods 2005 were the result of intense rainfall rather than the physical characteristics of the drainage basin January 2005 was a major even for Carlisle, as there was a major event. The rainfall was immensely high from the 6th to the 8th of January, during which two months of rainfall, although the previous days had high rainfall. During the flood, the rivers such as Eden, Kent and Derwent were the highest on record. The flood peaked in the upper parts of the Eden and Derwent catchments in the early hours of January 8th. In Carlisle, the River Eden peaked at an estimated 1520 m3/s at the Sheepmount Gauging Station at 140hrs on the 8th of January. This flow had returned again after approximately 175 years. Many geologists and people could say that the floods were cause by human impact, but in reality, that would be unlikely, but not impossible. It would not have been one of the major factors that cause the floods in Carlisle. However for example if, the vegetation in the river or around the river basin was removed or cut down, for the use of more land, or materialistic things, this could have affected the velocity of the river, as vegetation such as trees, act as an interception in the river causing its velocity to slow down. Also the land around the river basin is grassland and arable farming, especially in the valleys, so
Assess the costs and benefits of one river management scheme you have studied
Assess the costs and benefits of one river management scheme (15 Marks) There are various arguments for and against the management of the Mississippi and in particular the method of hard engineering used. The Mississippi drains approximately one third of the USA and is a major transport route therefore it is essential that the river is managed efficiently in order to protect jobs, businesses and homes. Although the management failed in 1993 the volume of water was not accounted for, the sporadic volume was not designed to be matched by the management. In effect the budget was set out to prevent specifically flood of a lower volume of water, it can be argued that up until the 1993 floods it was working perfectly. In addition an argument against the management of Mississippi that floods have gotten worse was proved false as records at the time were inaccurate. It was also suggested that some levee's breaking may have saved towns further upstream. Furthermore the jobs created by the construction of levees, flood walls and wing dykes and other management techniques have boosted the economy. There was also extremely hazardous antecendent conditions that could not be predicted, there was 200% more rain than usual for the particular time of year and people were unprepared in the west were flooding is uncommon, this could not be accounted for when managing the floods for the
Analyse How the Inputs and Outputs from a River Basin Can Vary Over Time
Analyse How the Inputs and Outputs from a River Basin Can Vary Over Time Both the inputs to and outputs from a river basin can vary both spatially (in different areas) and temporally (over time), due to daily, seasonal and annual occurrences. Precipitation mainly reaches the grounds surface from the atmosphere as snow and rain. Heavy snow is often intercepted and stored on the tops of hills and mountains and may lead to a decrease in river levels. Some rainfall may fall directly into the stream or river and some may fall onto the land and flow into the river basin through a variety of routes including throughflow, stemflow and overland flow. The intensity and duration of precipitation has a short term but regular effect upon both the inputs and outputs of a river basin due to the weather patterns. Over a short period of time, for example a week, the precipitation levels over the river basin can significantly vary, as on some days of the week the total precipitation can be extremely high and the next it could be virtually zero. Long periods of rainfall are the main cause of flooding as the soil has become saturated it reaches its infiltration capacity and infiltration is reduced, therefore increasing the frequency of surface run off and the risk of flooding. In addition to the weather having a large impact on the inputs over a short period of time in and around the
"Glaciated Uplands are landscapes of erosion: glaciated lowlands are landscapes of deposition" examine the validity of this statement with reference to glaciated areas you have studied
"Glaciated Uplands are landscapes of erosion: glaciated lowlands are landscapes of deposition" examine the validity of this statement with reference to glaciated areas you have studied Arran is an ideal place to look at when examining the validity of the statement. During the Devensian Glacial, the ice sheet covering Britain reached its furthest extent, totally covering Arran. This helped to shape the landscape. In around 11,000BP the Loch Lomond Readvance occurred. This time Arran was not covered by an ice sheet but its valley glaciers grew. This formed many of the features still clearly seen on the island today. They show fresh and visible signs of the glacial erosion and deposition that once occurred. Glacial erosion is caused by ice movement combined with material within it. One type of erosion is abrasion. This occurs when pieces of rock held within the ice rub against other pieces of rock wearing them down. Another type of erosion is plucking. This occurs when ice freezes onto a piece of rock on the valley side. When the glacier moves away it may then be broken off. For these processes to occur it helps to have a steep gradient, as this will lead to ice flow. A harsh climate is also needed, which is cold, to encourage ice formation and accumulation. These conditions are often found in upland areas. Glacial deposition is caused by melting when material is dumped in
How does the Efficiency and Cross-Sectional Area of a River Change Down Stream?
How does the Efficiency and Cross-Sectional Area of a River Change Down Stream? For my investigation I will be looking at the cross-sectional area of a river and how this affects efficiency in the river of Little Beck as the stream moves downstream from the source to nearer the mouth. To do this I will be taking measurements of the cross sectional area and the efficiency at 12 different sites along the river (See fig. 2 for map of river and 12 sites). The source of May Beck is approximately at a height of 280m on Fylingdales Moor in the North Yorkshire Moor National Park. The river flows south to join the Parsley beck, and the combined flow of these two rivers, now called the Little Beck, becomes tributary of the much larger river, River Esk, which reaches the sea at Whitby. During my investigation, I will be comparing my results to that of the Bradshaw Model. The Bradshaw Model is a model of an ideal stream (see fig. 1). By using this I can compare my results with the model to see how ideal Little Beck is. According to the Bradshaw model, at the source of the stream the cross-sectional area and efficiency are low at the source but as you move down stream they increase. Three key questions I have constructed to help me with my investigation are: . How does efficiency change as you go down stream compared to the predictions of the Bradshaw Model? 2. How does
An Investigation of Channel and Stream Characteristics For Streams on the Isle of Arran
An Investigation of Channel and Stream Characteristics For Streams on the Isle of Arran Aims To investigate hypothesis associated with increasing distance down stream for streams on the Isle of Arron. Objectives To set up and test hypothesis To investigate how channel characteristics change with increasing stream order. Hypothesis . As the river progresses downstream the bedload decreases in size. 2. The bedload becomes rounder in shape downsream. 3. The width will increase in size as the river goes downstream towards the mouth of the river. 4. The velocity of the river will decrease as it goes downstream. 5. The depth will increase in size as it goes downstream. 6. The discharge will also increase as it goes downstream. Theory There are three processes by which material is transported from land to the sea (via rivers) these are: i) Weathering-physical and chemical breakdown of rocks. ii) The slope-the products of wethering are moved down the gravity gradient in mass movements by the slope wash processes. iii) Fluid transfer-water, air and ice. The load, carried by natural streams, can be separated into three compounds. The material carried by the river is called the rivers load. It comes from river erosion and weathering of the river banks. Especially when the river is bankfull, considerable quantities of load can be carried. The total amount
Upper Porter Valley in Sheffield - source related study.
History Around Us By Philip Jacobs Introduction On Tuesday 10th June 2003 and Wednesday 18th June 2003 I visited the upper Porter Valley in Sheffield. The purpose of these visits was to give me an understanding and provide evidence to aid me in answering the following questions. a) Would your visit to Shepherd Wheel give you enough evidence to support what is said in Sources A, B and C? b) Consider all the sites you have visited to help you answer the following question b) i) How useful are the various sites in the Upper Porter Valley for learning about water powered sites and the cutlery industry before 1850? b) ii) Is there sufficient evidence in the valley to provide a good understanding of Porter Valley's water powered sites and cutlery making industry? a) Would your visit to Shepherd Wheel give you enough evidence to support what is said in Sources A, B and C? Source A - The heyday of the water mill in Sheffield was in the late 1700s when the streams were often so crowded that the tail goit of one mill fed the dam of the next. The Forge and the Wheel - J G Timmins Source A says that "the heyday of the water mill in Sheffield was in the late 1700s". At Shepherd Wheel there is little evidence to support this claim. Though a small, modern plaque outside the workshop says that a Mr. Shepherd employed 10 men to work for him in 1794. This can be seen in figure
Describe and explain the physical and human causes of flooding and the possible solutions that may be undertaken to prevent flooding and to deal with it.
Flooding Essay. Describe and explain the physical and human causes of flooding and the possible solutions that may be undertaken to prevent flooding and to deal with it. There are many factors that contribute to the causes of flooding. These causes can either be human, (things that happen due to human life and civilisation) or physical, (things that happen naturally to cause flooding). Physical causes: The drainage basin is the area of which the river drains its water from. The boundaries are marked by the watershed. There are many different ways of which water can enter the river channel. Some ways are quicker that others. The quickest are examples like surface run-off. This happens when the rate of precipitation exceeds the rate of infiltration, so it flows over the top of the surface and into the river. The slowest ways for water to travel are groundwater flow. Precipitation has to infiltrate through the soil then pass horizontally through permeable rock and into the river. These can increase the risk of flooding as the water is getting to the river quicker. This will cause a mass excess of water to run into the river and flood its banks. Groundwater flow will stop water getting to the river channel quicker but it will eventually get there. Also if storage of water is held somewhere this can increase the risk of flooding. For example surface storage occurs when the