CGP Eden Basin Case study

• The Eden Basin is in Cumbria
• The water cycle causes a lot of water to be thrown at the Eden Basin
• The water cycle means the Eden Basin is wet and just wants to make sure it stays hydrated, but it does cause issues
• The River Eden

  Flows through Cumbria
• The Eden drainage basin


  • In north-west England, between the mountains of the Lake District and the Pennines
  • The river drains the north-east Lake District fells and the north-west Pennines
• The River Eden's source

  In the Pennine hills in south Cumbria
• The River Eden


  1. Flows north-west through Appleby-in-Westmorland and Carlisle

  2. Its mouth is in the Solway Firth at the Scottish border
• The river basin


  • Largely rural, although the River Eden does flow through the city of Carlisle
• The upland areas that drain into the River Eden

  • Experience extreme weather that can cause flooding downstream
  • Carlisle is particularly vulnerable as it's at the confluence of the Eden, Petteril and Caldew rivers, and is fairly low-lying
• Rainfall is higher than the national average in the Eden Basin, because of the relief of the area-the mountainous main encourages orographic rainfall
• High rainfall means that lots of water enters the river channels
• The Eden Basin


  • Long and relatively narrow, which increases lag time
  • The slopes within the basin are steep, which reduces lag time and increases peak discharge
  • Made up of a number of different types of rock
• The highest ground, to the west of the basin


  • Made of igneous rocks, which are impermeable - water won't soak into them, so infiltration is very slow and surface runoff is high in these areas, reducing lag time
• Much of the basin

  • Made up of limestone and sandstone, which are permeable - when precipitation falls in these areas, infiltration is quick and there is little surface runoff, increasing lag time, and the amount of water in ground stores increases
• Land use changes in the Eden Basin have affected the drainage basin's water cycle and increased flood risk
• Farming

  • More intense farming has caused soils to become compacted, eg by heavy machinery or trampling by livestock - this reduces infiltration, so surface runoff is higher, meaning water levels in rivers rise quickly during heavy rainfall, increasing the risk of flooding
  • Grazing in upland areas, eg hill farming of sheep, has also reduced the amount of vegetation that can intercept rainfall, resulting in more water reaching rivers
• Construction


  • Although the majority of the Eden Basin is rural, built-up areas have increased - many new housing estates have been built in and around Carlisle, and there are plans to develop a huge garden village to the south of the city, including up to 10,000 new homes
  • Surfaces in built-up areas tend to be impermeable, which reduces the size of infiltration flows and greatly increases the size and speed of surface runoff flows
  • Some new developments, particularly near Carlisle, have been built on floodplains, creating a flood risk to property and requiring the construction of flood defences to protect homes - building on floodplains can cause flooding downstream as water that would naturally infiltrate on the floodplains flows downstream instead
• Deforestation


  • Has taken place in the basin for thousands of years, eg to provide timber and land for farming - much of the original forest cover in the Eden Basin has now been removed, giving way to large areas of open grassland and heathland
  • Trees increase infiltration and decrease runoff, so deforestation means more rapid and flashier flood hydrographs and a greater risk of flooding
• Climate change is predicted to change rainfall patterns in the UK - parts of the western UK could get up to 39% more winter rainfall by 2080, which would increase runoff and flood risk in the Eden Basin
• Storm Desmond


  • Caused devastating flooding in Cumbria in December 2015, with some of the worst flooding occurring in the Eden Basin
  • In some areas of Cumbria, there was record rainfall - in Shap, a village in the Eden Basin, 262.6 mm of rain fell in 48 hours between the 4th and 6th December, nearly 50% more than the average rainfall for the whole of December
  • Appleby-in-Westmorland and Carlisle were particularly badly affected, with more than 2,000 properties flooded in Carlisle alone, leaving many people homeless
  • The hydrograph shows the River Eden's response to Storm Desmond, with the gauging station that recorded this information located at Linstock, just upstream of Carlisle
• There are loads of different things you could investigate in a convenient drainage basin, such as factors affecting flows and stores in the water cycle, or how rock type and land use affect flows within a drainage basin
• You could measure the response of a river to precipitation, using primary or secondary data - in England, the Environment Agency regularly publishes river flow readings from its gauges on its website
• Changes in the water cycle have affected flood risk or sustainable water supply in the Eden Basin