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Explain one reason why a stream is found at base of chalk on top of clay
Water flows through the permeable chalk and comes to the surface when it reaches the clay .
Explain one way in which destructive waves can increase the rate of coastal erosion
Destructive waves have a stronger backwash which means they remove more beach material .
Explain one reason why river velocity usually increases with distance downstream.
Tributaries join the main channel which means that there is more water in the river .
Explain one way in which farming affects the landscape.
Farming clears the natural surface vegetation/trees , which can result in a mono-culture and/or artificial landscape
Explain one way rip rap helps protect coastal landscapes.
Large (manmade) boulders are placed along the cliff line which protect the coast by acting as a sea wall
Explain one way channelisation helps manage river landscapes.
Making the channel wider or deeper increasing the capacity of the river to hold water
Weathering is a process that can alter the landscape. State one other example of a physical process that affects the landscape.
erosion, transportation, deposition or mass movement
Explain one way in which mechanical weathering affects the landscape.
Rocks expand when hot and contract when cold , which can result in cracks forming and/or pieces of rock breaking off if a rock is heated and cooled many times
Explain how one human activity increases the chance of coastal flooding.
Reclaimed land is built on which is easily flooded as it is often below sea level/low lying and flat
Explain one way the weather and climate can affect river erosion.
Seasonal variations in rainfall/temperature, which increases discharge during winter months/reduces erosion during summer months
Describe the features of a granite landscape.
High altitude, steep rocky slopes with thin soil. Lots of streams. Rocky outcrops called tors. Little human activity
Describe the features of a limestone landscape
Fairly high, limestone pavements with clints and grykes, stream which disappear into pot holes. Can be steep with thin soild. Little human activity - possibly sheep farming and forestry
Describe the features of a chalk and clay landscape
Higher chalk and low lying clay. Gentle dip slopes and steep scarp slopes. Cattle grazing and sheep farming on hills
Describe how settlement can affect the landscape
Woodland and fields can be changed and replaced by tarmac and concrete leaving more impermeable surfaces and less plants
Describe how agriculture can affect the landscape
Woodlands and hedgerows can be chopped down for fields for crops and animals. Planting one type of crop and ploughing fields can change the look of the land.
Describe how the valley shape changes from source to mouth
At the source in the upper course the valley sides are very steep and the valley floor is very narrow. Towards the middle course the valley sides get less steep, not as high and the floor begins to widen. In the lower course, the floodplain, flat valley floor can extend for several km with smaller, gentler slopes at either side.
Describe how the river channel and discharge changes from source to mouth
In the upper course, near the source the river channel is narrow and shallow, with an irregular floor and there is little water in the streams. As you go down into the lower course the river channel becomes deeper and wider carrying a lot more water and more streams join it.
Describe how the river landscape changes from source to mouth
Rivers tend to begin on steep hills or moorlands with v-shaped valleys and interlocking spurs. Waterfalls and gorges can be found as you start to move down stream. In the middle course you may find small meanders. In the lower course you find much larger meanders, sometimes turning into oxbow lakes as they migrate across the wide flooplain. Levees can be foud at the side of the river banks.
Describe how river processes change from source to mouth
In the upper course, vertical erosion is key as the river cut into to land with all types of transportation. Deposition of large angular rocks. In the middle course the rocks become smaller and more rounded due to abrasion and attrition and lateral and vertical erosion widen the valley floor. In the lower course, lateral erosion is dominant and sediment is much smaller and rounder.
Describe how human activity changes from source to mouth.
In the upper course, in the hills, there is little human activity other than recreation and possible sheep grazing and forestry on more sheltered slopes. Towards the middle course you may find smaller settlements and more transports link with sheep famring on the hills and cattle grazing and some crops in the valley floor. In the lower course there are larger settlements and industrial estates on the flatter land. More road and rail links as it is easier to build on.
Explain hard engineering can reduce river flooding
Channeling can widen, straighten and deepen rivers so the river can hold more water and make it faster to reduce flooding. Flood walls are built to keep water in the river and prevant homes flooding. Dams can be built to control the amount of water flowing in the river.
Explain how soft engineering can reduce the impacts of river flooding.
Land use zoning means activities such as cattle grazing and sports fields are closest to the river whereas homes and expensive buildings are placed further away, higher up so they are not affected by the flood water. Wetland restoration allows areas to flood and plants more vegetation to absorb the water to reduce the flow lower downstream.
Explain how v-shaped valleys and interloking spurs are formed.
In the upper course of the river, vertical erosion cuts down into the land creating deep channels. Mass movement means the sides collpase and material is transported away leaving the v-shaped sides. Sometimes areas of harder rock cannot be eroded so water flows around it leaving interlocking spurs.
Explain how waterfalls and gorges are formed
There are areas of hard rock lying on top of a softer rock. The softer rock is more easily eroded by hydraulic action and abrasion, forming an undercut which leaves the harder rock above unsupported. Over time this collpases in to the plunge pool and the waterfall retreats upstream. This repeats until and steep sided gorge is left with the waterfall at one end.
Explain how meanders and oxbox lakes are formed
Faster flowing water on the outside of the bend causes lateral erosion forming river cliffs and moves the river sideways. Water flows more slowly on the inside leading to deposition which forms a slip off slope. Over time the neck of the meander gets narrower under two side joins. The river takes the straighter path, cutting off the old meander leaving an oxbow lake behind.
Explain how floodplains and levees are formed.
Lateral erosion over long periods widens the valley floor as meanders migrate acroos the land. In times of flood, water rushes over the banks of the river, depositing the largest material first, next to the river, which over time forms natural embankments called levees. The smaller sediment of silt flows over the land, being deposited to make the level of the land higher.
Describe the features of constructive waves
Longer wave length, lower height, stronger swash, deposits material up the beach. Created in calmer conditions
Describe the features of destructive waves
Shorter wave length, taller height, stronger backwash, removes material from the beach, created in storm condition
State the four main processes of erosion
hydraulic action, abrasion, attrition, solution
State the main types of transportation.
traction, saltation, suspension, solution, longshore drift
State the 3 main types of weathering
Mechanical, chemical, biological
State 2 types of mechanical weathering
Freeze thaw and exfoliation
State 2 types of mass movement
Land slide and soil creep
Describe the features of a concordant coastline
Rocks are parallel to the coast often forming coves
Describe the features of a discordant coastline
Rocks are at angles to the coast often leading to headlands and bays. Bays often have crescent shaped beaches in them
Explain the formation of cliffs and wave cut platforms
Waves erode the base of the cliff forming a wave cut notch at the base. This gets bigger over time leaving the cliff above unsupported. Weathering can weaken the cliff leading to mass movement and the cliff collapses retreating in land. The repeats over time and a flat, rocky shelf is left behind at the low tide line call a wave cut platform.
Explain the formation of stacks
There are weaknesses and faults in the rock in a headland. Hydraulic action and abrasion make this cracks bigger until they become caves. Erosion continues to make these caves bigger until the erode all the way through the headland forming an arch. Weathering weakens the rock above the arch until it collpases through mass movement leaving a rocky outcrop called a stack. Erosion continues on the stack until it collpases leaving a stump.
Explain the formation of spits and bars
Material in transported along the coast by longshore in the direction of the prevailing winds and waves. As the coastlin change direction, water becomes more sheltered and has less energy so material is deposited on the seafloor. This builds up over time to become above sea-level and extends further out in to the bay. A river may stop the spit growing further to join the coast further on and river sediment can be depotied behind the spit creating a saltmarsh. If the is no river a bar can form, joining two headlands with a lagoon fromed behind it.
Explain 3 types of coastal hard engineering
Sea walls are large concrete barriers designed to reflect wave energy to reduce erosion and stop flooding. Rip rap are large boulders placed at the foot of cliffs to absorb wave energy and reduce erosion. Groynes are rock or wooden structures which go out to sea to stop lonogshore drift, This creates bigger beaches which help to reduce wave energy at the cliff face.
Explain 2 types of coastal soft engineering
Beach replenishment is pumping sand onto beaches from offshore to create a bigger beach to absorb mre of the waves energy. Offshore reefs are piles of large boulders place out to sea to absorb the wave energy before they reach the coastline.