River Landscapes » The River Tees and Flood Risk

Why we study an example river

You now know how rivers shape the land. The exam also asks you to use an example of a river valley in the UK to identify its major landforms of erosion and deposition. In this lesson the example is the River Tees in northern England.

The Tees starts high in the North Pennines, near Cross Fell, and flows about 137 km east to the North Sea near Middlesbrough. Along the way it passes through almost every landform you have met. You can follow it from the hills to the coast.

Key terms:

• Flood risk: how likely it is that a flood will happen and how much damage it could do.
• Precipitation: all water falling from the sky, such as rain, snow, sleet and hail.
• Geology: the type and structure of the rocks in an area.
• Relief: the height and steepness of the land.
• Impermeable: does not let water pass through. Permeable rock does.
• Land use: what the land is used for, such as farming, forest or housing.

The upper course: landforms of erosion

Near its source the Tees is small, steep and fast. It cuts down into the land with vertical erosion, so the valley is narrow and V shaped. Here you find the landforms of erosion.

Further upstream, the river tumbles over a steep rocky stretch at Cauldron Snout. Interlocking spurs are also found in the upper valley, where the river winds around them.

The middle and lower course: landforms of erosion and deposition

As the Tees flows east, the valley opens out and the land flattens. The river carries more water and has more load. Sideways erosion becomes more important than downward erosion.

• Meanders: large bends develop in the lower valley. A well known example is the meander around the town of Yarm, where the river almost loops back on itself. The river erodes the outside of each bend and deposits sediment on the inside.
• Flood plain: the wide, flat valley floor that floods when the river overflows. Rich silt left behind makes good farmland, so it is often used for farming.
• Levees: when the river floods, the coarser material drops first beside the channel and builds up natural banks.
• Estuary: at the mouth the river widens as it meets the North Sea. The Tees estuary has wide mud flats where fine silt is deposited. It is also an important place for wading birds.

What is flood risk?

A flood happens when a river carries more water than its channel can hold, and the water spills onto the flood plain. Flood risk depends on how likely a flood is and how many people and buildings are in the way.

The Tees valley contains towns such as Barnard Castle, Darlington, Yarm, Stockton and Middlesbrough. Most are on or near the flood plain, so flood risk matters to many people. Two sets of factors decide how risky a river is: physical factors and human factors.

Physical factors affecting flood risk

The upper Tees has high rainfall and steep slopes, and much of the upland soil and rock does not let water through easily, so water reaches the river fast. A flood in the hills can then travel downstream to the towns on the flood plain.

Human factors affecting flood risk

People can make flooding more likely through land use.

• Urban areas: roads, roofs and pavements are impermeable. Water cannot soak in, so it flows into drains and then into the river very quickly.
• Deforestation: trees catch rain on their leaves and take up water through their roots. With fewer trees, more water reaches the river faster.
• Farming: bare ploughed fields or soil packed down by animals let water run off the surface instead of soaking in.

Building houses on the flood plain also increases flood risk, because more people and buildings are in the path of the water.

Exam-style question

(a) Name one landform of erosion on the River Tees and describe where it is found. [2 marks]

(b) Explain how land use can increase the flood risk of a river. [3 marks]