UK Landscape Case Studies: Environmental Influences and Human Management

Landscapes change through interacting processes

The Dorset coast and the River Tees basin show how physical conditions and human decisions combine to shape UK landscapes. Geomorphic processes are the natural processes that change the shape of the land. Weathering weakens rock where it lies; erosion removes material; transport moves it; and deposition leaves it behind. Gravity also moves material downslope through rockfalls, slides and slumps.

These processes operate at different spatial and timescales. A wave may remove material from one cliff face, while longshore drift transfers sediment between stretches of beach. Rain falling across a drainage basin can affect river flow far downstream. Some changes happen during one storm; others accumulate over decades or longer. Management can therefore have effects beyond the place where a defence is built.

Dorset: geology controls where erosion is fastest

The Dorset coast forms part of the Jurassic Coast, which extends for about 155 km from Exmouth in Devon to Poole in Dorset. Its sedimentary rocks include relatively resistant limestone and chalk, alongside less resistant clay. Both the resistance of the rocks and the arrangement of their bands influence the coastline.

At Lulworth Cove, waves breached the resistant limestone band at the coast. Once water reached the softer clay behind it, erosion widened the sheltered bay much more rapidly than it widened the limestone entrance. This is differential erosion: neighbouring rocks are worn away at different rates. It explains why a small-scale opening can lead to a much larger coastal landform.

Around Swanage and Studland, softer sandstone and clay occur behind the bays, while the more resistant chalk of The Foreland forms a headland between them. Geology therefore helps explain contrasts across a whole stretch of coast, not just the shape of an individual feature.

Weathering and erosion also work together. Chemical weathering weakens chalk, while vegetation can contribute to biological weathering. Wave erosion then removes weakened material. Where cliffs become unstable, mass movement can cause sudden retreat rather than a steady, gradual loss.

Dorset: everyday conditions and exceptional storms

Waves repeatedly erode cliffs and move beach sediment. At Swanage, longshore drift carries beach material mainly from south to north. The beach is a store of sediment, but it also protects the land behind it by absorbing wave energy. Losing beach material can therefore increase the exposure of the coast to erosion.

An extreme event can produce much faster change. On 14 February 2014, a major storm brought winds of up to 80 mph and waves over 30 feet high to the coast. Waves moved shingle from Chesil Beach into streets behind the seafront, and parts of the beach were lost. At West Bay, cliff collapses caused retreat of a few metres. These examples show how one event can rapidly reshape a beach or cliff that has developed over a much longer period.

The storm was a weather event, whereas climate describes longer-term conditions. Rainfall influences weathering and cliff stability: water entering and saturating cliff material can encourage slides and slumps. Climate change also raises coastal risk through sea-level rise, caused by warming seawater expanding and the melting of land ice. A higher sea level allows waves and flooding to reach farther inland, especially on low-lying coasts. This does not mean that every stretch of coast changes at the same rate: geology, height above sea level and protection still matter.

Swanage: protecting one beach changes sediment movement

At Swanage, management alters the same processes that naturally shape the coast. Timber groynes installed in 2005–06 trap sediment moving by longshore drift. Retaining sediment creates a wider beach, which absorbs more wave energy and reduces erosion behind it.

However, trapped sediment no longer travels as freely along the coast. Beaches farther along the drift route can receive less material, become narrower and provide less protection. The benefit at one location can therefore create a disadvantage elsewhere.

Recurved concrete sea walls protect much of Swanage’s beachfront by reflecting waves away from the land. They protect buildings and infrastructure, but reflected water can remove sediment from the beach and scour beneath the wall. Preventing erosion also reduces the local supply of new sediment from the protected land. A defence can therefore protect the shoreline while contributing to a lower beach in front of it.

Beach replenishment supports these structures by replacing lost sediment. In winter 2005–06, sand and shingle dredged from the seabed at Poole Harbour were added to parts of upper Swanage Bay. The wider beach reduced wave energy reaching the cliffs and properties. The scheme cost about £5 million and requires repetition approximately every 20 years.

This combination shows why management needs evaluation rather than a simple judgement that it is ‘good’ or ‘bad’. Groynes and sea walls provide protection, while replenishment maintains the beach’s natural protective role. Yet sediment losses, effects farther along the coast and repeated spending remain important. Decisions need to consider a connected coastline rather than each defence in isolation.

Dorset: tourism and extraction also affect processes

Not all human impacts are deliberate attempts to protect the coast. Along the Jurassic Coast, visitors wear down footpaths and trample cliff-top vegetation. Removing vegetation exposes soil and rock to weathering and erosion and can contribute to cliff instability.

Limestone quarrying on Portland exposes rock surfaces to weathering and erosion. Commercial shingle extraction from Chesil Beach continued until the 1960s. Material was removed faster than natural processes could replace it, damaging the landform. Here, human activity changed the balance between sediment removal and replenishment.

The Tees: climate and geology create a rapid river response

The River Tees basin provides a contrasting river landscape. Its upper course includes open moorland and rough grazing; farming occupies fertile floodplains farther downstream; and the lower course becomes increasingly urban and industrial around the estuary.

Annual rainfall in the upper course exceeds 2,000 mm. Much of its bedrock is impermeable, and the peat is saturated for more than six months of the year. Impermeable rock limits water passing down into the ground, while already saturated peat has little capacity to store additional rainfall. More water therefore flows over the surface and reaches river channels quickly.

These conditions produce a short lag time and a ‘flashy’ response: river discharge can rise rapidly after heavy rain. The sudden rise is sometimes called the Tees roll or Tees wave; the river level can rise by about one metre in 15 minutes.

This connects basin-scale conditions to channel-scale processes. Rainfall over the uplands supplies water to the river; the resulting higher flow can increase its ability to erode and transport sediment. When flow loses energy, deposition becomes more likely. Seasonal and year-to-year changes in rainfall therefore influence how actively the river reshapes its channel and floodplain.

The Tees: people regulate water and reshape the channel

Reservoirs built in the upper and middle courses during the 1960s and 1970s met growing demand for water. Cow Green Reservoir, completed in 1971, holds about 40,000 million litres and regulates flow downstream. Holding back water changes the timing and amount of water entering the river below the dam, so rainfall and downstream discharge are no longer linked entirely by natural drainage processes.

People have also directly altered the channel. During the nineteenth century, meanders towards Stockton-on-Tees were removed to improve navigation. Removing the Mandale loop shortened the river route by about 4 km, reducing the distance travelled by boats. This was a direct reshaping of the river landscape for transport, rather than a landform produced solely by erosion and deposition.

At Yarm, flood gates and gabions provide local protection. Gabions are stone-filled wire cages that help protect vulnerable banks from erosion. Downstream from Middlesbrough, embankments help contain high river levels, restricting the river’s natural tendency to spread onto its floodplain.

The Tees Barrage, completed in 1995, reduces the risk of flooding from a storm surge entering from the sea. This is a different source of flood risk from heavy rainfall in the uplands: managing a river basin also means considering its connection to the coast.

Judging the combined effects

In both landscapes, human activity changes the operation of natural processes rather than removing them. Swanage’s groynes interrupt sediment transport; Cow Green regulates water flow; and embankments restrict where floodwater can spread.

A useful evaluation asks three connected questions: what is protected, which process is altered, and where or when might a disadvantage occur? Swanage’s wider beach protects property but reduces sediment movement farther along the coast. Tees management supports water supply, navigation and flood protection, but also creates a more controlled and physically modified river. The landscape that results reflects both natural conditions and human priorities.