Types of erosion 

• Hydraulic action 

  • The water that sashes against the river banks

  • Air becomes trapped in the cracks of the banks and bed 

  • This causes the rock to break apart 

• Abrasion 

  • Pebbles grind along the river bank and bed 

  • Sand papering effect 

• Attrition

  • When the rocks that are going downstream knock against each other

  • They break apart and become smaller and rounder

• Solution 

  • Water dissolves certain types of rocks 

  • eg . limestone 

Types of Transportation 

• Traction 

  • Large heavy pebbles roll along the riverbed

  • Common near the source of river as load is larger 

• Salutation 

  • Pebbles bounce along the riverbed 

  • Common near source 

• Suspension 

  • Lighter sediment is suspended within the current 

  • Common near mouth

• Solution

  • Movement of dissolved chemicals 

  • Varies along the river

  • Depends on the presence of soluble rocks 

Deposition 

• When the river loses its energy 

• It drops any material it has been carrying 

  • In shallow waters 

  • At the end of the rivers journey, The mouth

  • When the volume of water decreases

Drainage basins 

• River’s water can fluctuate over time

• It's the hydrological cycle that explains why the amount of water in the river fluctuates 

• A drainage basin is the land around the river is drained by the river and its tributaries

• Tributaries

  • A small river that joins the main river channel

• Watershed 

  • The area of high land forming at the edge of a river basin

• Source 

  • The river begins 

• Mouth 

  • The river meets the sea 

• Confluence 

  • The point at which two rivers meet 

• Channel

  • This is where the river flows 

River Profile 

• Long profile 

  • Is a line representing the river from its source to its mouth.

  • How the river changes over its course

  • Can show Upper course to lower course 

    • Upper course 

      • Where the river starts 

      • Often upland area 

      • River load is larger as it hasn’t eroded yet

    • Lower course

      • Flatter land 

      • Rivers load is fine sediment as erosion has broken down the rocks  

• Cross profile 

  • Shows the cross section of a rivers channel and valley at a certain point along the rivers course 

  • Shows the different features of the river

  • So you can see the difference between upper, middle and lower course 

    • Upper course

      • Vertical erosion 

      • Shallow and narrow channel

    • Middle course

      • Some vertical erosion but mostly lateral erosion 

      • Channel is wider and deeper 

    • Lower course 

      • Less erosion but only lateral erosion 

      • Channel is at its widest and deepest