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Unlock This CourseThe spec asks for one detailed example of the causes and impacts of a flood for a named river, and how it was managed. Our example is the flooding of the Somerset Levels in the winter of 2013-14. It is a good one because many of the ideas from Why Rivers Flood and What Floods Do and Managing River Floods show up in one place. Here we apply them rather than teach them again.
Location: the Somerset Levels and Moors are a large, flat, low-lying area in south-west England, in the county of Somerset. Two rivers drain the area: the River Parrett and its tributary the River Tone. The Parrett flows north through Bridgwater to the Bristol Channel. It is one of the lowest areas in the UK, and large parts of it lie below the height of the highest tides.
December 2013 to January 2014: storm after storm brings heavy rain and water builds up on the Levels.
January 2014: the Parrett and Tone overflow. Roads close and villages are surrounded by water.
Early February 2014: the flooding is at its worst. Muchelney is cut off, the Prince of Wales visits, and Royal Marines are sent to help.
February to March 2014: extra pumps are used, then dredging of the Parrett and Tone begins.
2014 onwards: the Somerset Levels and Moors Flood Action Plan is put into action.
Key figures (rounded): about 100 million cubic metres of floodwater covered about 65 square kilometres, and about 165 homes were flooded. In many places the water stayed for weeks.
Notice how the causes work together: heavy rain on saturated ground, flowing onto flat land, with the tide blocking the exit. It was this combination, not one single cause, that made the flood so serious and so long-lasting.
Sort impacts into social, economic and environmental.
| Type | Impacts |
|---|---|
| Social | About 165 homes flooded and people had to leave their homes. The village of Muchelney was cut off by floodwater for weeks. Roads were closed, which made it hard to reach work, shops and services. Many residents suffered stress and worry. |
| Economic | Farmland was flooded for weeks, so farmers lost grazing and crops and had to move or feed livestock. Businesses lost trade, and repairing homes and roads was costly. |
| Environmental | Fields and wetland habitats lay under water for weeks. This was far longer than normal winter flooding, so some wildlife was harmed. Floodwater also left silt on the land. |
The impacts were felt at different scales. Locally, villages and farms were hit hardest. Regionally, roads across Somerset were disrupted. Nationally, the flood drew a lot of attention, and the government came under pressure to act.
Remember that strategies are action plans and agreements, and techniques are the methods used.
For flooding, sustainable means reducing flood risk in a way that works in the long term and does not harm the environment or future generations.
| Technique | Strengths | Weaknesses |
|---|---|---|
| Pumping | Quick and moves a lot of water | Costs money and power to run, and does not tackle the cause |
| Dredging | Helps rivers carry more water | Must be repeated as silt builds up, can harm wildlife, and may not help in extreme floods |
| Raising roads | Keeps villages like Muchelney connected | Does not stop homes and fields flooding |
| Tidal barrier | Protects thousands of homes and businesses | Very expensive, and does not stop flooding from heavy rain upstream |
| Upstream land management | Sustainable, works with nature, helps wildlife | Slow to take effect, and works best for smaller floods |
Who benefits? The tidal barrier protects the town of Bridgwater and its businesses. Raised roads help villages like Muchelney and their residents. Upstream land management benefits the whole river catchment, and wildlife too. Dredging mainly helps farmers and residents beside the rivers.
Overall: about £80 million was spent on flood defence and risk management over the ten years after the flood. A mix of harder techniques (pumps, dredging, barrier) and softer ones (land management) is stronger than any single method. The hard techniques protect people quickly, but natural flood management is the most sustainable. Even so, no scheme can fully protect land this low and flat from another extreme winter.
Answer the questions about the flooding of the Somerset Levels in 2013-14.
(a) Identify two physical causes of the flooding. [2 marks]
(b) Describe two impacts of the flooding on people. [2 marks]
(c) Explain why dredging was only part of the solution. [3 marks]
(d) To what extent were the strategies and techniques used to manage the flooding sustainable? [6 marks]
(a) A very wet winter with a series of storms (1); low-lying, flat land that drains slowly (1).
(b) About 165 homes were flooded and people had to leave their homes (1); Muchelney was cut off for weeks and roads were closed (1).
(c) Dredging helps rivers carry more water (1), but the land is very flat and low (1), and high tides stopped water draining out to sea, so other techniques such as pumps and a tidal barrier were also needed (1).
(d) Top level (5-6 marks): Some of the management was sustainable but not all. Upstream land management, such as the Slow the Flow work, holds water back using trees and hedges, which works with nature and helps wildlife, so it is sustainable. Dredging and pumping are less sustainable because dredging must be repeated as silt builds up, and pumps need power and money to run. The tidal barrier at Bridgwater will protect about 11,300 homes, but it is very expensive and does not solve heavy rain upstream. The Flood Action Plan combines several methods over 20 years, which is a strength, and about £80 million has been spent, so cost is a weakness. Overall the plan was partly sustainable: the best long-term parts were the natural methods, but the harder techniques were needed to protect homes quickly.
In a "to what extent" question, give a judgement at the start and end, and support it with named techniques.