Eden Basin Flashcards
1
Q
- Where is the Eden basin?
- Where is the source of the River Eden?
- Where does the River Eden flow?
- Where is the mouth of the River Eden?
A
- North-west England between mountains of the Lake District and the Pennines.
- In the Pennine hills in south Cumbria.
- North-west through Appleby-in-Westmoreland and Carlisle.
- In the Solway Firth at the Scottish border.
2
Q
- What is Hell Gill Force?
- How has it formed?
- What is there below it?
A
- A waterfall near the source of the River Eden.
- It has formed where there is a change in the rock type from hard limestone to soft sandstone. The water has eroded the soft rock, forming a step in the river channel.
- A steep-sided gorge, left behind as the waterfall has retreated up the valley.
3
Q
- Fill in the blanks: many streams ____ down the _____ ______ of the hillsides at the ____ of the basin from about ___m above sea level.
- What 3 processes have caused V-shaped valleys to form?
- Give a place where this has occurred.
A
- Many streams flow down the steep slopes of the hillsides at the edge of the basin from about 600m above sea level.
- Weathering (by freeze-thaw); transportation (by traction); and erosion (by abrasion).
- The north-east lake district.
4
Q
- What happens as more tributaries join a river?
- What happens to the river valley in the lower course?
- Give a place where this has occurred.
- What landforms have been created over time as a result of this?
- How have these landforms been created?
- Give a place where this has occurred.
A
- The river gets bigger, giving it more power to erode the river channel sideways.
- It becomes wider and flatter, and meanders form on the valley floor.
- Near Salkeld.
- Ox-bow lakes.
- Erosion causes the outside bends of a meander to move get closer until only a small bit of land remains (the neck). The river breaks through this land, usually during a flood and the river flows along the shortest course. Deposition eventually cuts off the meander, forming an ox-bow lake.
- Where Briggle Beck joins the Eden near Salkeld.
5
Q
Fill in the blanks:
* ________ is built on the _________ of the River Eden. Here the land is ___-_____ and quite ____ (less than 100m above sea level).
* As _______ have ________ across the valley floor, the __________ has become _____.
* ________ has also been _________ when the river has _______, which has _____ __ the __________.
A
- Carlisle is built on the floodplain of the River Eden. Here the land is low-lying and quite flat (less than 100m above sea level).
- As meanders have migrated across the valley floor, the floodplain has become wider.
- Sediment has also been deposited when the river has flooded, which has built up the floodplain.
6
Q
- Where is Cumbria?
- What’s its climate like?
A
- The west coast of the UK, facing the south-westerly prevailing winds.
- It’s one of the wettest parts of the UK, and frequently experiences periods of intense rainfall. The area normally has cool summers and mild winters.
7
Q
- Where is it coldest on the River Eden floodplain?
- Why do landslides occur on the River Eden?
- What happens to the material from the landslides?
A
- On higher ground, such as near the source of the River Eden. In winter, this ground can freeze.
- During cold periods, freeze-thaw weathering slowly breaks up the exposed rock of the valley sides in the upper course of the river. When the valley sides are weakened, sudden mass movement becomes more likely.
- It’s added to the river’s load, increasing the erosive power of the river through abrasion.
8
Q
- What happens to the ground during periods of intense rainfall?
- What 2 things does this cause?
- What does a higher volume of water in a river do?
A
- It becomes saturated, making it less stable.
- The river bank can slide or slump into the river channel; and rain can flow quickly over the surface and into the river, increasing the volume of water.
- It increases the power of the river to erode: by hydraulic action as there is more water; and transportation increases so abrasion is caused (particularly in the river’s upper course).
9
Q
- What types of rock are found at the high ground and why?
- What can limestone be vulnerable to?
- What rock type found in the west of the basin tend to be impermeable?
- How does this cause V-shaped valleys to form?
A
- Harder rocks around the edge of the basin as they are more resistant to erosion.
- Carbonation weathering.
- Igneous rocks.
- As the water can’t soak into the ground, high rainfall causes lots of surface streams to form, which have a lot of power to erode vertically, created steep-sided V-shaped valleys.
10
Q
- Through the rivers middle and lower courses, what is the river valley made up of?
- What does the river’s increasing volume in its lower course cause?
A
- Sandstone
- It increases the energy of the river so that there is lots of lateral erosion of the sandstone. This widens the river channel, forming meanders and steep river cliffs.
11
Q
- How many km of flood defences (flood walls and embankments) have been built and where?
- What are they designed to do?
- In what 2 ways do they affect the natural processes of the river?
A
- 10km along the Rivers Eden and Caldew in Carlisle.
- To contain the water within the river channel, so that the floodplain can be built on.
- They can prevent the natural formation of meanders; and they can prevent the deposition of sediment on the floodplain.
12
Q
- What has happened to Castle Carrock Beck, a stream to the south-east of Carlisle?
- In what 4 ways do reservoirs affect a river?
A
- It has been dammed to create a reservoir.
- They limit the natural flow of water downstream; material carried by the river is deposited in the reservoir and not along the river’s natural course; this can then increase erosion downstream; and reduces the natural buildup of the floodplain in the lower course of the river.
13
Q
- Near Dalston (which is south of Carlisle), how has the landscape been changed?
- Why has this been done?
- What is a side effect of this?
A
- 1000 trees have been planted.
- To reduced flooding and to reduce erosion by stabilising the soil.
- Trees intercept rainfall, reducing surface runoff, which in turn prevents rapid increases the river’s volume because it takes longer to reach the channel. As a result of this, the river will have less energy, reducing erosion and meaning that meanders may take longer to form.
14
Q
- In the past, how was the landscape of the River Eden changed?
- What did this cause?
- What has happened more recently?
- Give one place where this has happened.
- What do meanders cause?
A
- It was changed by channel straightening. Many sections of the river were diverted into artificial channels to try and reduce flooding.
- It allowed the water to flow more quickly than it normally would, increasing erosion and reducing deposition.
- Some areas of the basin have been restored to their original state by having artificial meanders put in.
- On the River Lyvennet to the south-west of Appleby.
- They slow the river’s flow, increasing deposition. This encourages the river to meander more naturally, allowing the natural build up of the floodplain.
15
Q
- What has been cleared by humans in the upland of the Eden Basin?
- What has this caused?
A
- Natural woodland and heathland has been cleared from many areas.
- This has increased surface runoff when it rains, and means that more water ends up in river channels more quickly. The volume increase gives rivers more energy for erosion, and can cause sliding and slumping of the river banks.
