River Flooding Case Study and Management

This lesson examines a major UK flood event in detail and then explores the full range of flood management strategies — both hard engineering and soft engineering — available to reduce flood risk. Understanding these strategies and the conflicts they create is essential for the Edexcel B exam.

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UK Flood Case Study: The Somerset Levels, Winter 2013-14

The Somerset Levels in south-west England experienced the most severe and prolonged flooding in living memory during the winter of 2013-14. The floods lasted for over three months, making it one of the most significant flood events in recent UK history.

Background: The Somerset Levels

Feature	Detail
Location	Somerset, south-west England
Landscape	Extremely flat, low-lying land — much of it at or below sea level
Land use	Mainly pastoral farming (cattle grazing); some nature reserves (e.g., RSPB Ham Wall)
Drainage	Relies on a network of artificial drainage channels (called rhynes, drains, and pumping stations) to keep the land dry
Rivers	The River Parrett and River Tone are the main rivers; they are tidal in their lower reaches
Soil	Peat and clay — holds water; slow to drain

Causes of the 2013-14 Floods

Cause	Detail
Extreme rainfall	The winter of 2013-14 was the wettest on record in England. From December to February, some areas received over 400 mm of rain — more than double the average.
Prolonged storms	A succession of Atlantic storms brought 12 major storm events between mid-December and mid-February.
High tides	High tides in the Bristol Channel prevented the rivers from draining to the sea, causing water to back up.
Flat, low-lying land	Water could not drain naturally — it pooled on the flat, low-lying terrain.
Clay and peat soils	These soils became quickly saturated and could not absorb further rainfall.
Lack of river dredging	The Environment Agency had reduced dredging of the River Parrett and River Tone since the mid-1990s, allowing sediment to build up and reducing channel capacity. This became a major political controversy.
Existing drainage infrastructure	Pumping stations and drainage channels could not cope with the sheer volume of water.

Effects of the Floods

Category	Effects
Social	Over 600 homes flooded; some people displaced for over a year. Villages including Muchelney and Thorney were cut off for weeks — accessible only by boat. Mental health impacts: anxiety, depression, community stress. Schools closed.
Economic	Approximately 17,000 hectares of farmland flooded. Livestock had to be evacuated. Estimated agricultural losses of over £10 million. Damage to roads and infrastructure — the A361 was closed for weeks. Total estimated cost: £100-150 million. Business disruption in local towns.
Environmental	Pollution from sewage, agricultural chemicals, and oil spread across the floodplain. Some wildlife habitats damaged. However, the floods also created temporary wetland habitats that benefited bird populations. Fertile silt deposited on farmland.

Exam Tip: The Somerset Levels case study is powerful because it combines physical causes (extreme rainfall, flat land, clay soils) with human factors (lack of dredging, drainage infrastructure, land management decisions). In your exam answer, make sure you discuss both types of cause to show balanced understanding.

The Dredging Controversy

The floods sparked a fierce public debate about river dredging:

Viewpoint	Argument
In favour of dredging	Dredging the Rivers Parrett and Tone would increase their capacity, allowing them to carry more water. Local farmers and residents blamed the Environment Agency for stopping dredging.
Against dredging	The Environment Agency argued that dredging has limited effectiveness in such extreme events, is expensive (ongoing cost), and can damage riverbank habitats. Dredging was eventually carried out in 2014 (8 km of river dredged at a cost of £6 million), but experts debated whether it would have prevented the flooding.

Response to the Floods

• The Somerset Levels and Moors Flood Action Plan (2014) was created, committing £100 million to improved flood management.
• 8 km of the Rivers Parrett and Tone were dredged.
• A tidal barrier on the River Parrett at Bridgwater was planned (completed 2024).
• Pumping capacity was increased.
• Road levels were raised.
• Upstream storage areas were created.

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Flood Management Strategies

Flood management strategies are divided into hard engineering (structural, built solutions) and soft engineering (working with natural processes).

Hard Engineering Strategies

Strategy	Description	Advantages	Disadvantages
Dams and reservoirs	A dam is built across a river valley. The reservoir behind it stores water during heavy rain, releasing it slowly.	Controls flood peaks very effectively; the reservoir can also supply water, generate hydroelectricity, and provide recreation	Very expensive (tens of millions of pounds); valley behind the dam is flooded (destroying habitats, farmland, sometimes villages); sediment is trapped behind the dam, reducing downstream supply; alters the natural river regime
Channel straightening	Removing meanders to create a straighter, shorter channel. Water flows faster through the straightened section.	Moves flood water through the area more quickly; reduces local flood risk	Transfers the problem downstream — flood water arrives faster at the next settlement; destroys meander habitats; can cause bank erosion
Flood walls and embankments	Concrete walls or earth banks built alongside the river channel to increase its capacity.	Protects specific areas effectively; can be combined with other measures	Expensive to build and maintain; can look ugly; if overtopped, water is trapped behind them; give a false sense of security
Channel deepening and widening	Dredging or mechanically enlarging the river channel to increase its capacity.	Allows the river to carry more water without overflowing	Expensive; needs repeating regularly as sediment builds up; can damage riverbed habitats
Diversion channels (flood relief channels)	An artificial channel built to divert excess water away from a vulnerable area.	Very effective at reducing flood risk in specific locations; water can be diverted to a safe area	Expensive to build; transfers flood risk to the area where the water is diverted; land required for the channel

Soft Engineering Strategies

Strategy	Description	Advantages	Disadvantages
Afforestation	Planting trees in the upper catchment. Trees intercept rainfall, increase infiltration (roots create channels in the soil), and absorb water through uptake.	Cheap; natural; reduces run-off; provides habitat; carbon sequestration; long-term sustainable solution	Slow — trees take years to grow and become effective; less effective during winter when deciduous trees have no leaves; land must be taken out of farming
Washlands / flood storage areas	Designated areas of land (usually farmland) that are deliberately allowed to flood during high-discharge events, absorbing excess water and protecting settlements downstream.	Relatively cheap; creates wildlife habitats; effectively reduces peak discharge downstream	Farmland is lost during flood events (farmers may need compensation); land is not available for development
Floodplain zoning	Planning regulations that restrict or prevent development on floodplains. High-risk areas near the river are left as open space; development is only allowed further from the river.	Prevents people and property being put at risk in the first place; no construction costs; cheap	Politically unpopular — restricts development and reduces land values; does not help people already living on floodplains; difficult to enforce in areas with housing shortages
Sustainable drainage systems (SuDS)	Features designed to slow the flow of surface water in urban areas: permeable paving, green roofs, swales (shallow channels), detention basins, rain gardens.	Reduces urban run-off; relatively cheap to install in new developments; improves water quality; enhances green space	Expensive to retrofit to existing development; requires maintenance; limited effectiveness during extreme events
River restoration	Returning a river to its natural state — removing artificial straightening, reinstating meanders, reconnecting the river to its floodplain.	Restores natural flood attenuation; creates habitats; improves water quality; sustainable long-term	Can increase flood risk locally (more flooding of the floodplain); land required; may conflict with agricultural use
Flood warning systems	The Environment Agency issues flood warnings via text, email, TV, and its website. Warning levels: Flood Alert → Flood Warning → Severe Flood Warning.	Gives people time to prepare (move valuables, evacuate); saves lives; relatively cheap to operate	Does not prevent flooding — only reduces its impacts; not everyone receives or acts on warnings; limited effectiveness for flash floods