Courses of a river

Courses of a river

1. Upper course

   • Fast flowing, narrow river
   • SOURCE - start of a river (BOGGY LAND)
   • V shaped valley
   • Interlocking Spur - edges of hills
   • Formation of a waterfall
     • 1. A river flows over hard rock with a band of softer rock below.
     • 2. The softer rock is undercut and the hard rock is left overhanging.
     • 3. A plunge pool is formed by HYDRAULIC ACTION and ABRASION
     • 4. The hard rock collapses and the plunge pool is deepened by ATTRITION
     • The rock continues to erode and the waterfall retreats toward the source forming a GORGE

2. Middle Course

   • River channel getting wider
   • MEANDERS form as the river slows
   • U shaped valley
   • Wide, flat, fertile FLOODPLAIN
   • Formation of a MEANDER
     • 1. The river flows faster on the OUTSIDE of thereunder, ERODING (hydraulic action and abrasion) and forming a RIVER CLIFF
     • 2. The river flows more slowly on the INSIDE of the river and deposits it's load forming a SLIP OIFF SLOPE/RIVER BEECH.

3. Lower Course

   • The river flows across a FLAT, FERTILE FLOODPLAIN in the middle and lower courses.
   • The water is flowing slowly and deposits SILT (alluvium) on the river bed
   • The build up of silt raises the river above the FLOODPLAIN
   • FLOODING continues a build up of SILT on the sides of the river
     • These are often called LEVEES (natural embankments) which can then protect against further flooding