Paper 1 section A - UK Weather Hazards – Flooding caused by extreme rainfall Key Facts of the Example – Somerset levels flood Where are the ‘County of Somerset, Low lying farmland between the Mendip Hills to the north, the Quantocks to the west and the Bristol Channel. The area contains the Somerset River Parrett, River Tone, River Axe and the River Brue. All flow out to the Bristol Channel. Much of the area lies at or below sea level and has been flooded for Levels? centuries. It was drained in the 17th century to make farmland. The grass growing here is rich in nutrients due to flooding and produces excellent beef and lamb. Crops are rarely grown due to flooding Natural cause Wettest January since records began. Series of depressions (low air pressure) from the Atlantic resulted in 350mm of in January and February 2014 – of 2014 floods 100mm above average. High tides and storm surges from the Bristol Channel stopped river water from reaching the sea. It spilled over the river banks onto the low lying land. Rivers had not been dredge for 20 years. The heavy rainfall caused fast surface runoff from the Mendips and the Quantocks into the drainage basin creating the flooding. Because the land is so flat, the floodwater cannot drain away. It saturates the soil. Human causes Rivers had not been dredged for over 20 years. This meant silt had built up on the river bed reducing the capacity of the river channel Social impact 600 homes flooded and 16 farms abandoned, Moorland and Muchelney were cut off with no one getting in or out – business couldn’t be supplied and kids couldn’t get to school and people couldn’t get shopping or got to the doctors. Residents evacuated for months in temporary housing. Electricity cut off. Economic Somerset County Council stated a £10,000,000 repair cost which came from tax payers money – money that could be used on local services, 14,000 hectares of Impact land under water for nearly 4 weeks – no farming production in this time so farmers lost money, 1000 cows and sheep evacuated, local roads and Bristol – Taunton railway line closed at Bridgewater – this affected commuters as they couldn’t get to work. Insurance costs showed a steep increase for homeowners and businesses Environmental Floodwater heavily contaminated with sewage, oil and chemicals which harmed the wildlife and ecosystem. Also there was a risk to drinking water meaning impact that bottled water had to be bought for weeks after the flood. A huge amount of debris needed clearing and disposing of. Stagnant surface water had to be re- oxygenated before returning to the river – this had to be done by the Environment Agency Responses Residents of Muchelney and Burrowbridge had to use rowing boats to visit local shops. 2014 £20 million action plan between SCC and the Environment Agency launched to reduce future flood risk. Dredging of the Rivers Tone and Parrett increase river capacity, road levels raised above flood plain, Burrowbridge and Muchelney villagers provided with home flood defence. Pumping stations built on the Huntspill River banks raised and reinforced with a planned 2024 tidal barrier at Bridgwater. Areas of low lying farmland allowed to flood to ease river discharge near the urban areas of Bridgewater and Glastonbury.

Map of the Somerset Levels Key terms Somerset County Council, Environment Agency, dredging, river capacity, pumping The dark areas show the stations, Quantock and Mendip Hills, Bristol Channel, Storm surge, high tide flooded areas

The Parrett flows to the , blizzards, , prolonged rainfall, heatwave, heavy snow and Bristol Channel. High/Storm extreme cold, strong winds, tide forces the river water back up stream. Atmospheric pressure, Atlantic depressions

The proposed barrier at Successes, since the flooding in 2013 and 2014 following EXTREME rainfall, there has Bridgwater will stop this from happening been no widespread flooding on the Somerset levels, despite heavy rainfall and high amounts of runoff from the Mendip, Blackdown and Quantock hills. Dredging has Muchelney was cut off increased the channel size. More water can be drained away from the Levels.

This has resulted in lowering insurance costs, farmers not losing money during the floods and local businesses being able to trade throughout the year

Paper 1 – Extreme weather hazards Thunderstorms Prolonged rainfall Drought and heatwaves Heavy Snow and Extreme Cold In July 2014 dramatic electrical storms Extended periods of rainfall lead to rivers The UK has experienced long dry spells and Long periods of severe winter weather have resulted in 3000 lightning strikes across flooding. The ground becomes saturated hot weather which leads to drought. In become less common in recent years, but southern Britain. This followed an extended (cannot hold more water – think of a 2003, 2000 people died across with there are occasions when heavy snow and period of raised temperature or heatwave. sponge). When the water cannot drain the UK recording the highest temperatures severe cold can cause a great hardship to away, it stays as surface water and floods. on record with 38.5°C in Kent. The 2006 people particularly in the north of the UK These powerful thunderstorms can also The 2014 Somerset floods resulted from drought in the UK was due to a sequence of result in flash floods such as the 2004 350mm of rainfall in one month. It generally extremely dry summer – freezing winter In 2009 parts of the south west and the Boscastle flood. happens during the late winter, and the with low rainfall – extremely dry summer. south east were affected by heavy snow when the snow melts in the mountains in with 20cm falling in London Flash floods occur when there is a short the early spring. Other examples are 2009 Heatwaves affect the elderly and sick, and period of extremely torrential rain landing Cockermouth, Lake District when record can kill, affect the natural In 2010 much of the UK was hit by heavy on a steep gradient or no porous rainfall fell in November. Summer 2007 environment, reducing water levels in lakes snow in December. Northern rock/surface. The rain quickly fills the river affected Hull, Sheffield and Gloucestershire and rivers, which reduces oxygen levels. recorded a record low temperature of - channel causing a violent torrent flood. – loss of life, 2008 – south west and north 18.7°C. Winds came from the north and west England and Christmas 2015 following Water supplies become lower in quality and north east to create these conditions This happened in Lancashire at Christmas in the warmest and wettest December since can be undrinkable with many areas having 2015 also – Mr Bone was there and saw it records began. mains water to homes cut off. Generally first hand! caused by southerly winds Extreme weather Evidence of increased extremity Strong winds Weather describes the day to day atmospheric conditions. It includes termperature, clouds, There was a gap from 2003 – 2007 with no The UK gets extremely strong winds from rainfall, strength and direction of wind. Weather hazards are extreme events, and even notable extreme weather events. time to time. They are not hurricanes as it though the UK has a moderate (mild) climate, it has a fair share of extreme events. The is not possible to get them in the UK. weather in the UK is mainly driven by the SW prevailing wind from the Atlantic. It is warm From 2007 – 2016 there were extreme Winds though can and have reached and moist bringing strong wind and plenty of rainfall. Think of the UK as a roundabout or events every year with 2014 the most active 100mph. In February 2014, winds travelling meeting place of winds. Wind directions can change from SW to NE and bring different year with floods, high winds, and record from the Caribbean battered South Wales, snowfall ripping up trees, leaving 21000 without conditions. There is evidence that the extreme events are becoming more frequent, partly power, with huge waves battering the due to , but also because our weather patterns are becoming stuck. This Records have been broken 3 times since south west of the UK. Clifton suspension when the jet streams change direction or latitude (N or S). 2007. 2014 had 100mm more rain than bridge needed to be closed for the first Significant events are Heatwave, Heavy Snow and Floods caused by powerful storms. average, 2015 wettest December in history, time ever, as did the Severn bridge. 2003 had the hottest recorded temperature 38.5°C

Linked to climate change tentatively