Carlisle Floods 2005

Carlisle Floods 2005

1. Impacts

   • Affected 2,700 homes
   • 3 people died
   • Cost of damage estimated to be £400 million
   • Flooded services such as fire stations and police stations

2. Causes of flooding

   • Vegetation
     • Mixed arable and grassland in valleys and rough hill pasture on uplands
       • Due to the floods taking place in January, there is less vegetation, decreasing interception making peak discharge higher. Farmland means more compacting soil reducing infiltration
   • Geology
     • Includes impermeable slate and volcanic rocks in Skiddaw area and sandstone and limestone in the Vale of Eden
       • Due to Carlisle lying on impermeable rock, the water is not absorbed into the soil properly, meaning the water reaches the river more quickly
   • Soils
     • Thin soils on much of the upland area, deeper soils and alluvium in the valleys
       • Thin soils means difficult infiltration as they can't cope with the water volume
   • Rainfall
     • Intense rainfall 201,286,000m^3 leading to a 73% runoff of 147,205,000m^3
       • Heavy rainfall on soil which is saturated from a previous period creates over flooding. The intensity and duration also effects this as the infiltration capacity of the soil is exceeded
   • Relief
     • Significant areas of upland with steep slopes characterise much of the upper basin. Much lower gradients around Carlisle
       • Water will not infiltrate if on a steep slope as all of the water will want to go down the hill
   • Urbanisation
     • Limited in upland regions, increasing spread of towns and villages in valley areas
       • There is an increase on the rate o impermeable rock which decreases the amounts of soil. Water is drained and pumped back into the river
   • Basin shape and size
     • The rivers Caldew, Petteril and Birthing have a confluence with the Eden just before or in Carlisle itself
       • Carlisle is built on a confluence meaning there is water from two river

3. Key Facts

   • Carlisle is situated on the floodplain of the River Eden with three river meeting in the city
     • Eden
     • Petteril
     • Irthing
   • The catchment is mainly rural which covers 2,400km^2
   • It is home to 244,000 people