River Landforms in the UK

How rivers shape distinctive landforms

A river landform is a recognisable feature created by river processes. Some features, such as waterfalls, result mainly from erosion. Others, such as meanders, develop through both erosion and deposition. Flood plains and levées accumulate sediment deposited by floodwater.

Two directions of erosion help explain the pattern. Vertical erosion cuts downwards into the riverbed; lateral erosion wears away the banks and widens the channel and valley. Vertical erosion generally dominates in the upper course, while lateral erosion becomes more important downstream. These are tendencies, not rigid boundaries: local rock type and relief also influence which landforms develop.

Interlocking spurs: a river winding around hillsides

In an upland valley, ridges of land can project from alternate sides, rather like fingers reaching towards one another. These are interlocking spurs. The river winds between them along a narrow valley floor, much of which may be occupied by the channel.

The upper-course river mainly cuts downwards through hydraulic action—the force of flowing water—and abrasion, where transported sediment scrapes the bed. It does not erode sideways enough to remove the resistant projecting ridges, so it follows a route around them.

Meanwhile, weathering breaks up rock on the valley sides, and mass movement carries loosened material downhill. The river removes this material. Together, downward river erosion and the breakdown of the valley sides produce a steep-sided, V-shaped valley with interlocking spurs. These bends around hillsides are different from the large meanders that migrate across broad flood plains downstream.

Waterfalls and gorges: erosion followed by collapse

A waterfall is a sudden drop in a river’s bed. A common explanation for its formation involves resistant rock overlying less resistant rock. ‘Hard’ and ‘soft’ here describe their relative resistance to erosion.

The softer rock wears away more quickly through hydraulic action and abrasion, creating a drop. Falling water and swirling rock fragments deepen a plunge pool at its foot. Erosion also removes softer rock beneath the resistant layer, undercutting it and leaving an overhang.

Eventually, the unsupported overhang collapses. Fallen rock fragments provide more material for abrasion in the plunge pool. Undercutting and collapse repeat, moving the waterfall upstream. This retreat leaves a narrow, steep-sided gorge downstream of the waterfall’s new position.

The waterfall and gorge are therefore connected stages of the same process: the waterfall retreats, and the gorge marks the route it has left behind.

Meanders: erosion and deposition on opposite banks

A meander is a winding bend in a river. In a meandering channel, the fastest flow is towards the outside of the bend. Hydraulic action and abrasion erode this bank, undercutting it. Bank collapse creates a steep river cliff and shifts the outside edge of the bend outwards.

Water flows more slowly on the inside of the bend. It cannot carry as much sediment, so sand and gravel are deposited along the inner bank, building a gently sloping slip-off slope that extends into the channel.

Picture a cross-section across the bend: a steep, eroding outer bank faces a gently sloping, depositional inner bank. Because erosion removes material from one side while deposition adds it to the other, the bend grows and shifts across the valley floor. This movement is called meander migration.

Ox-bow lakes: a bend becomes disconnected

As a meander grows, erosion on its outer banks can bring neighbouring parts of the channel closer together. The strip of land between them—the meander neck—becomes narrower.

During a flood, the river can cut through this neck. Water takes the shorter, straighter route rather than travelling around the old bend. Flow into the abandoned bend slows, encouraging deposition at its entrances. Sediment eventually seals both ends, leaving a curved ox-bow lake separated from the main channel.

The complete sequence needs both processes: erosion narrows and breaches the neck, while deposition cuts off the former bend.

Flood plains and levées: the deposits left by floods

A flood plain is the broad, relatively flat land beside a river. Lateral erosion and meander migration help widen the valley floor. Repeated flooding then deposits sediment across it, building up layers of alluvium—river-deposited material.

When a river overflows its banks, water spreads across the surrounding land. Contact with the land surface increases friction and slows the water, reducing its ability to carry sediment. Material is deposited across the flood plain.

The larger, heavier particles settle first, close to the channel. Finer particles travel farther before settling. Repeated floods therefore build raised banks beside the river, called natural levées, while finer sediment accumulates farther away. In cross-section, the levées stand above the surrounding flood plain. They are natural deposits, not constructed flood defences.

Estuaries: deposition where rivers meet the sea

An estuary is a tidal river mouth where freshwater meets seawater. It is influenced by both river flow and tides, rather than being shaped by the river alone.

The river carries sediment towards its mouth, and incoming tides can bring in additional material. Where the incoming tide slows river flow, deposition occurs. Sediment accumulates to form mudflats, which may be exposed at low tide. Vegetation can eventually colonise suitable mudflats, helping sediment build up into salt marshes.

Tides also redistribute sediment, so estuarine deposits change over time. Deposition creates features within the estuary; it does not mean that the entire river mouth is permanently filled with sediment.

A UK example: the River Tees

The River Tees, in north-east England, flows approximately 137 km from Cross Fell in the Pennines eastwards to Teesmouth on the North Sea. Its valley connects the processes above to named places.

In upper Teesdale, near Cauldron Snout, the river winds around interlocking spurs within a steep-sided valley. These identify an upland landscape where downward erosion is important.

High Force, west of Barnard Castle, is a waterfall associated with the resistant Whin Sill, made of the igneous rock dolerite, locally called whinstone. It overlies less resistant sedimentary rocks, including sandstone, shale and limestone. Faster erosion of the underlying rocks undercuts the resistant layer. Repeated collapse and upstream retreat have left a steep-sided gorge.

Farther downstream, meanders occur around Barnard Castle and south-east of Darlington. These illustrate the combination of outer-bank erosion and inner-bank deposition on lower, gentler terrain.

The lower Tees has a wide flood plain, particularly around Yarm and towards Stockton-on-Tees. Repeated flooding deposits sediment and builds natural levées beside the channel.

At Teesmouth, near Middlesbrough and Redcar, the river enters a large estuary. Deposition forms mudflats and sandbanks, while tidal action redistributes their sediment. The Tees therefore provides named examples of upland erosion, meander development and lower-course deposition.

Erosional landforms

• Interlocking spurs: upper-course river cuts downwards and winds around resistant ridges projecting from alternate valley sides. Weathering and mass movement help create the V-shaped valley.
• Waterfall: resistant rock overlies softer rock → differential erosion → plunge pool and undercutting → overhang → collapse.
• Gorge: repeated undercutting and collapse cause upstream waterfall retreat, leaving a narrow, steep-sided valley.