The British Dam Society Lesson 1 - A new dam A new dam | Lesson 1 – Slide 1

What do you know about dams? A dam is a structure built to collect, retain and store water. Most UK dams store water to secure its supply and manage variations in availability across the seasons, or to provide large or small-scale flood management. While some include hydroelectric power, this currently only contributes around 1% of UK electricity consumption.   Most new UK dams are small, built to manage water at a local level for flood alleviation. What is a dam? What are they for? Where are they found? A new dam | Lesson 1 – Slide 2

2000 years ago Why did the Romans need to control water here? Image source: http://commons.wikimedia.org/wiki/File:Harbaqa_Dam,_Syria._Pic_01.jpg This is the Harbaqa dam in Syria. It was built by the Romans in around 200 AD. The Middle East is very dry, so it is difficult to irrigate fields for crops. Rainfall is unpredictable, so farmer’s don’t know exactly when good rains might come. The Romans built this dam 365 m long and 21 m high, to store water to irrigate the fields that supplied crops to the city of Palmyra. This is an example of a dam used to control and store water for irrigation. Why did the Romans need to control water here? A new dam | Lesson 1 – Slide 3

2000 years ago Image source: http://commons.wikimedia.org/wiki/File:Barragem_romana_Belas1.JPG These are Roman waterworks at Belas, near Lisbon in Portugal. The Romans built large cities across their Empire. People in these cities needed water for drinking, cooking, washing and other uses. The Romans built dams and waterworks to divert water and bring it to where people needed it most. This is an example of a dam used to secure a water supply for people to use. Why did the Romans use dams here to divert the flow of water? A new dam | Lesson 1 – Slide 4

1000 years ago What lived in the water behind this dam in England? Image source: http://www.geograph.org.uk/photo/962494 This is a medieval pond bay at Quainton in Buckinghamshire. Simple earthworks created a dam across a stream and when built, the dam had in its centre a sluice to control the level of water behind it. Dams like these were used to create fish ponds where fish for eating, such as carp, were farmed. Larger dams provided a store of water to power waterwheels for milling grains. This is an example of a dam linked to food supply. What lived in the water behind this dam in England? A new dam | Lesson 1 – Slide 5

200 years ago What revolution took place? From around 1750 the Industrial Revolution, which began in the Midlands, transformed how we use water – and how much we need. Dams were created to supply water to the growing industrial towns where it was used mainly for industry: to power watermills used in manufacturing textiles, steel and pottery, and to move goods from place to place through canals. Little of this water made it into peoples homes, which for many years lacked clean water and sanitation. Here, dams support industry. What revolution took place? Why did people need more water? A new dam | Lesson 1 – Slide 6

Today How do we use dams today? A new dam | Lesson 1 – Slide 7 Image sources: BDS photo competition These dams provide a water supply and hydroelectric power. How do we use dams today? A new dam | Lesson 1 – Slide 7

Today dams give us Water supply for living and working Flood control for safety Irrigation to help feed us Navigation for people and goods Power for homes and industry Dams don’t just include the giant ones that are most famous. Dams can be almost any size, from controlling streams to the huge Three Gorges Dam in China, the largest in the world. And many are even invisible: some reservoirs are underground, and many flood control dams stay empty most of the year, and just look like a field with earthworks in it. Dams are all around us, and are very much part of modern life. A new dam | Lesson 1 – Slide 8

What about tomorrow? Why might dams become more important? 1 2 3 4 5 6 7 8 Temperature Increase (oC) 2070-2100 Prediction vs. 1960-1990 Average Image source: http://commons.wikimedia.org/wiki/File:Global_Warming_Predictions_Map.jpg What changes might global warming bring to the UK and elsewhere? Why might these changes make dams an even more important part of life in the future? Consider: - Drought - Severe rain and extreme weather events - Rising population - The need for renewable energy - Rising sea levels Why might dams become more important? A new dam | Lesson 1 – Slide 9

A new dam Why might this town need a new dam? Use this when introducing the scenario in ‘A new dam’. Students should use the key provided on their printed copy of the map. Why might this town need a new dam? Where should you locate it? A new dam | Lesson 1 – Slide 10