Changes in River Characteristics (Edexcel IGCSE Geography)

Remember valley shape and river shape are not the same thing. If you are asked to describe valley shape you should focus on the gradient and shape of the land either side of the river channel.

• Location - North-East England

• Drainage basin - 1830km²

• Source - Cross Fell, Pennines 754m above sea level

• Length - 137km

• Mouth - Tees Estuary, North Sea

• The direction of flow is from west to east

Features of the River Tees

Upper course

• The land use in the upper course is moorland, with peat soil

• The land is mainly used for sheep grazing

• It has an average annual precipitation of over 2000mm

• The geology of the area is primarily limestone and sandstone

• The river channel in the upper course:

  • is narrow and shallow

  • has large angular bedload

  • has high levels of friction

  • is dominated by vertical erosion

  • has a steep gradient

• Landforms in the upper course include:

  • High Force waterfall where hard rock (dolerite also known as whinstone) overlies softer rock (limestone and sandstone)

  • a steep-sided gorge which is left behind as the waterfall retreats upstream

  • rapids

  • v-shaped valleys created by vertical erosion

  • interlocking spurs

• Human activity in the upper course includes:

  • Several dams and reservoirs, including Cow Green, built to supply the urban areas to the east

  • The dams also help to control discharge downstream

Middle course

• The land use in the middle course is mainly farmland as the river valley widens

• The number and size of settlements increase including Barnard Castle

• The geology continues to be dominated by limestone and sandstone

• Average annual rainfall decreases to approximately 1000mm

• The river channel:

  • increases in width and depth

  • gradient is more gentle

  • bedload is smaller and more rounded

  • experiences decreasing friction as less of the water is in contact with the banks and bed

  • is dominated by lateral erosion

• Landforms in the middle course include:

  • meanders which develop due to the increase in lateral erosion

Lower course

• The land use in the lower course includes:

  • arable farming

  • increasingly large settlements such as Middlesborough and Stockton on Tees

  • industrial areas

• Annual average rainfall decreases further to approximately 773mm

• The river channel:

  • increases in width and depth

  • gradient is very gentle

  • bedload is now small sediment

  • is dominated by lateral erosion and then deposition nearer to the mouth where the river becomes tidal

• Landforms in the lower course include:

  • large meanders

  • ox-bow lakes

  • levees

  • floodplains

• There is lots of human activity in the lower course impacting the river channel and the surrounding landscape

  • Flood prevention schemes in Yarm and other settlements

  • The Tees Barrage which was built to prevent flooding at high tides

  • River straightening downstream of Stockton to allow easier navigation further up the river

    • The Mandale Loop was a meander which was cut off to reduce the distance ships had to travel by 4km

  • Industrial developments on the floodplains close to the estuary