Eden Basin Flashcards
Where is the Eden basin?
NW England between the mountains of the Lake District and Pennines.
Where is the Source?
Pennine hills in South Cumbria
Where does the basin flow?
NW through Carlisle
Where is it’s mouth?
Solway Firth at Scottish border.
What do the upland areas that drain into the River Eden experience?
Extreme weather that can cause flooding
Why is Carlisle vulnerable?
Its at the confluence of the Eden, Petteril and Caldew rivers and its low-lying.
What is the rainfall like?
Higher than national average because of the relief.
What kind of rainfall does the basin have?
Orographic rainfall - higher than average
What is the landscape of the basin like?
What does this cause?
Long and narrow. Causes a increase in lag time.
What is the gradient of the slopes like?
What does this cause?
Steep.
Reduces lag time and increases peak discharge.
What is the highest part of the ground made of?
Igneous rocks - impermeable
What does igneous rocks cause?
Infiltration to be very slow and surface runoff to be high which reduces lag time.
What is the rest of the basin made of?
Permeable rocks - limestone & sandstone
What does permeable rocks cause?
Infiltration to be quick and little runoff increasing lag time.
Why has farming increased the risk of flooding at the Eden Basin?
2 reasons
Soil to be compacted - reduces infiltration so runoff is higher.
Grazing which reduces vegetation and interception.
Why has urbanisation increased the risk of flooding at the Eden Basin?
2 reasons
Impermeable surfaces - increased runoff speed and flow and reduced infiltration.
Built on floodplains - can cause flooding downstream.
Why has deforestation increased risk of flooding at the Eden Basin?
Fewer trees - increase in runoff and flashy hydrographs
What happened in 2015?
Storm Desmond
What did the storm do to some areas of Cumbria?
Increased rainfall - a record
How much rain (mm) fell in 48 hours in the Eden Basin?
262.6mm
How many properties were badly flooded in Carlisle?
Over 2000
What does an increase in rainfall do to the basin?
Lots of water enters the river channels.
What is the geology of the basin?
Underlain by sandstone and limestone
What does tree cover being loss reduce by deforestation?
Interception and runoff.
What are people’s predictions about flood risk?
That it will worsen over the 21st century
What does every 1C of temperature change increase?
Rainfall by 15%
What does the temperature change mean for seasons??
Winters will have wetter weather and summers will be drier
As a percentage how wetter has 2011-2020 been compared to 1961-1990?
9% wetter
What are 3 scenarios that links to emissions and flood risk?
If emissions continue to increase - flood risk gets worse
If emissions stabilise - flood risk stays the same or worse
If emissions reduce - flood risk decreases
What was deforestation like at the Eden Basin?
No forest cover so more run-off and flashier hydrographs
How much of Cumbria is forested?
17% in 2020
What was the percentage of cattle soil compaction between 2000 and 2009?
30%
What does grazing in upland areas reduce?
The vegetation and therefore reduces interception
What else has been a human factor linking to the potential of increased precipitation?
Anthropogenic climate change
How much can the rainfall increase by 2080?
35% or more by 2080
Why may precipitation increase?
As increased evaporation occurs in the Atlantic and Irish Sea
