the eden basin Flashcards
where does the river Eden flow
1) Eden Drainage basin is in North west England between LAKE DISTRICT —> PENNINES.
2) SOURCE is in the Pennine Hills in South Cumbria. Flows through a Appleby-in-Westmorland and Carlisle. MOUTH is in Solway firth at the Scottish Border
3) Largely rural drainage basin, although the flows through the city of Carlisle
4) Uplands —> experience extreme weather could cause flooding down stream. Carlisle is particularly vulnerable as it’s at the confluence of EDEN, PETTERIL and CALDEW rivers, and is low lying
what are the characteristics of the Eden basin that affect the water cycle
1) Rainfall higher than national average in Eden Basin. The mountainous terrain encourages OROGRAPHIC rainfall (precipitation produced when moist air is lifted as it moves over a mountain range)
2) Basin is relatively long and narrow, which increases lag time
3) slopes are steep —> reduces LAG TIME and increases PEAK DISCHARGE
4) highest ground made of igneous rock (impermeable - decreases lag time)
However most of the basin made up of LIMESTONE and SANDSTONE which are (permeable - increases lag time)
how has Farming increased flooding
1) soils become more compacted by heave machinery or trampling by liver stock, between 2000/09 -> 30% increase in cattle in Eden valley.
2) compaction of soil reduces INFILTRATION, so surface runoff is higher = water levels in rivers rise quickly during heavy rainfall, increasing risk of floods
3) Grazing in uplands areas (eg: hill farming of sheep) –> has also reduced the amount of vegetation that can intercept rainfall –> more water reaching rivers
How has construction increased the risk of flooding
1) Built up (housing estates) areas have increased eg: Huge garden village development to the south of the city, including up to 10000 new Homes.
2) Surfaces will most likely be impermeable, which reduced the size of infiltration flows and greatly increases the size of surface runoff flows
3) New developments have been built on new floodplains which has created flood risk to property and has required the construction of flood defences to protect homes —> flood defences can cause flooding down stream as water that would naturally infiltrate on the floodplains flows downstream instead.
how has deforestation increased risk of flooding
1) Deforestation occurred to provide timber and land for farming. much of original forest has been removed, giving way to large areas of open grassland and heathland
2) Trees increase infiltration and decrease runoff and decrease Throughfall as no interception = flashier floods
Storm Desmond on EDEN BASIN
1) December 2015, devastating floods in Cumbria
2) some areas of Cumbria has record rainfall. In Shap, a village in the Eden Basin, 262.6 mm of rain fell in 48hours —> that’s nearly 50mm more than the average month of December.
3) Appleby-in-Westmorland and Carlisle were particularly badly affected
-> more than 2000 properties flooded
-> many homeless
Fieldwork opportunities in the river basin
-investigate rock type and land use affect flows within a drainage basin
-measure soil saturation in different parts of the drainage basin with different rock types
-response of a river to precipitation
