River Wye

• Floodplains?

  • lateral erosion = widens river - deposition of fine sediment in storms
  • river floods + flows outwards from channel = less energy = deposits material it can't carry - heavy near river channel
  • many floods = build up of sediment either side = levees
• river Wye location?

  • starts in North-West Wales in Plynlimon and ends in South-East in Chepstow
  • mouth meets with river ~Severn in Bristol channel
  • travels through Hay-on-Wye in Wales and Hereford in England
  • 5th longest river in UK - over 210km (130 miles)
• flooding causes 7?

  • intense precipitation
  • really hard or frozen soil
  • really wet saturated soils
  • Steep valley slopes
  • melting snow
  • buildings with concrete and glass - urbanisation
  • deforestation
• intense precipitation?

  • physical cause
  • river is unable to hold all the water = burst banks and overflows
• hard or frozen soils?

  • physical cause
  • impermeable surface = water runs off at higher rate to reach rivers = causes flooding from extra water
• wet saturated soils?

  • physical cause
  • no more water can be absorbed = more surface runoff
  • water reaches river quicker = flooding
• steep valley slopes?

  • physical cause
  • due to gravity = quick runoff
  • river cannot hold extra water = bursts banks and overflows
• melting snow?

  • physical cause
  • happens mostly in spring - when temps increase
  • snow melts and increases volume of water = banks burst and overflow from high volume
• urbanisation?

  • human cause
  • materials are impermeable = quick runoff to rivers
  • water gets to drains and pipes = increases speed of water reaching river
  • river has too much water = floods
• deforestation?

  • human cause
  • less trees = less interception = increases surface runoff
  • rivers can't hold extra water = banks burst and flood
• geology summary of river Wye?

  • Near Hereford there is: limestone, shales and sandstone
  • Southern river: mudstones and sandstones (red soils) - where meanders occur
  • The steepest part (the gorge): limestone
  • Symonds Yat: meanders - mixture of limestone = steep cliffs, and sandstone = eroded