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UK physical (rivers) - Coggle Diagram
UK physical (rivers)
key words
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surface storage - water held in puddles, ponds and lakes
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hydrological cycle - continuous cycle between air, water and land
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Somerset levels
Effects
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as storms continue, military assistance is needed
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Human causes - dredging is a hard management method which has deepened drainage ditches, and the rivers Parrett and Tone. The deeper the river, the more water the channel holds, reducing flood risk.
Dredging Adv - reduced flooding, deepens channel to hold more water, levees created on the river bank
Dredging Dis - expensive, sediment soon builds up again
Physical causes - jet streams are high level atmospheric winds at around 8-10km altitude and these go across the Atlantic to the UK and drive low pressure systems. The jet streams have caused 12 major storms, most rainfall since 1766, high river discharge and storm surges
Location - The somerset levels are a broad system of flat low-lying land between Taunton and Glastonbury in Somerset, South-West England. The rivers Parrett and Tone can cause floods as their confluence is near the moorlands, which flow to the Bristol channel. This area is one of the UK's lowest lying areas with the highest point 8m above sea level. The soils here are fertile from alluvium and are good for summer grazing
Soft management
by allowing areas to flood, the somerset levels, which are a man made landscape for farming, can save other areas and create wildlife sanctuaries
future risks - climate change will bring more rainfall, storms and a rise in sea level. Severe flooding will be more likely in the UK. In order to make a difference, river management is needed to reduce flood risks
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2007 Sheffield floods
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Sheffield has a population of 577,800 people
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river processes
transportation
the movement of material down the river, occurs along the whole of the rivers long profile
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river courses
middle
the river is wide, deep and flat. The valley is flatter and wider. It contains smoother, smaller material. Features of erosion and deposition are meanders and oxbow lakes. It also has lots of lateral erosion
lower
the river is wide and deep. The valley is flatter and wider. Features f flood plains are levees and deltas
upper
the river is narrow and shallow. It contains large, angular material. Features of erosion are v-shaped valleys, waterfalls and gorges
the river profile is the long profile that shows the gradient of a river as it journeys from source to mouth (where it reaches the sea). It spans the source of a river to the mouth
the river is split into three courses - upper, middle and lower
rivers flow downhill. The start of a river is known as the source, and here the water is shallow, slow moving and the land is high. As the channel gets closer to its end, which is called the mouth the water is deep. The land is less steep here
discharge - the volume of water flowing in a river, measured in cubic meters per second. It is measured by area x velocity
velocity - the speed of the river, measured by meters per second
levees - these are a natural bank which is built up either side of the river through deposition over time, to create a barrier and prevent the river from overflowing and flooding
Deltas occur when the river has a high load which is deposited hwen the river slows down. It then builds up when the waves are weaker
distributaries - where the sediment blocks th river so it has to divide up into lots of different channels, called distributaries
