Rivers. Learning Intention. How people use rivers? Why is water and rivers important? Why study rivers? What is the hydrological cycle?. Starter. Write down 5 words that come to mind when I say the next word Rivers. What good are rivers?. Why study rivers?. Water. Effect on man.
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Learning Intention • How people use rivers? • Why is water and rivers important? • Why study rivers? • What is the hydrological cycle?
Starter Write down 5 words that come to mind when I say the next word Rivers
Why study rivers? Water Effect on man In the news Rivers Damage Deaths Food
Rivers • Water is an important resource we all need to live and survive. 70% of our bodies are water. • We see water all around us in the sea, lakes, ponds and rivers. • We are now going to take you on a journey to find where our water comes from and how rivers affect our lives.
List of Water Uses • In pairs discuss each persons list of uses for rivers • Has people’s reliance on rivers changed? How?
Washing Wash hands Drinking water Swimming Bath Cooking Fishing Water sports Dams Electricity (HEP) Crops Transport (move things and people) eg boats Sprinklers Factories Bread Water golf courses Uses of riversMake a spider diagram
Top uses of water Put list of uses for rivers in order of importance for: • Today • The past
Past uses of water • No washing machines/ dish washers– wash by hand • More travel by boat, few went by plane • More baths, less showers • No sprinklers • Less swimming pools – more swims in the lake • No automated car washes • Fewer golf courses – use a lot of water
Write an account Write an account of your group discussion. Write about how our use of rivers has changed over time.
The River’s journey • Write an account of the river’s journey from its beginning (source) to its end (mouth) • Use Video
3 courses Boulders Shallow Waterfalls V shaped valley Narrow, wider, very wide Shallow Floodplain, Tributary, Meanders, Ox-bow lakes, Pebbles Source, Mouth Erosion Transport Deposition Floodplains Points from Video
1. Source: the point at which the river starts. • 2. Interlocking spurs: where the river winds between ridges. • 3. Gorge: deep valley caused by wearing back of a waterfall. • 4. Waterfall: often where the river crosses a band of harder rock. • 5. 'V' shaped valley: produced in upper course because the river cuts down more quickly than the surrounding slopes are eroded.
6. Meander: the river starts to erode from side to side. • 7. River cliff: the river moves faster on the outside of the bend and cuts into the valley side. The erosion undercuts the ground causing it to collapse, leaving a cliff. • 8. River beach (Slip-off slope): the river moves more slowly on the inside of the bend. It cannot carry the larger pebbles and these are dropped here.
9. Ox-bow lake: during floods the river cuts through the neck of a large meander. The outside bend is left as a shallow lake. • 10. Flood plain: the river is flowing in a very wide, flat valley. When it floods, it spreads over the flood plain. • 11. Levée: during floods the overflowing river is slowed as it leaves its bed. Silt is deposited along the banks first. Over the years the deposits build up into high ridges. • 12. Estuary: the open mouth of the river, where it meets the sea.
River channel • A river is fresh water flowing across the surface of the land, usually to the sea. It flows in a channel. The bottom of the channel is called the bed and the sides of the channel are called the banks.
River terms Source - The source is the beginning of a stream or river. Mouth - The mouth is the end of a river, where it empties into a large body of water. Tributary - A tributary is a river or stream that flows into another stream, river, or lake. Confluence – to the point where a tributary joins a larger river. Drainage basin – the area drained by a river and its tributaries. Watershed – the boundary of the drainage basin which is usually a ridge of high land.
Fill in the spaces putting in the missing terms and the missing definitions
Shaping the land • The river works to shape the land. It does it in 3 ways: • Erosion – wears away the land • Transportation – moves the material from one place to another • Deposition – drops the material and builds new landforms
What is erosion? • Erosion is the wearing away of the land (like sandpaper) • Weathering breaks up and weakens the surface of the rocks while erosion wears away and removes the loosened material
Processes of erosion http://www.bbc.co.uk/schools/gcsebitesize/geography/riverswater/river_processesrev1.shtml
Processes of Erosion Erosion involves the wearing away of rock and soil found along the river bed and banks. Erosion also involves the breaking down of the rock particles being carried downstream by the river. There are four main forms of river erosion: • Hydraulic action - river wears away the river bank from underneath (force of the water against river banks) • Attrition - rocks being carried by the river smash together and break into smaller particles. • Abrasion - rocks carried along by the river wear down the river bed and banks • Solution - smaller particles are dissolved into the river. • http://www.bbc.co.uk/schools/gcsebitesize/geography/
Transport Rivers pick up and carry material as they flow downstream. A river may transport material in four different ways: • Solution - minerals are dissolved in the water and carried along in solution. • Suspension - fine light material is carried along in the water. • Saltation - small pebbles and stones are bounced along the river bed. • Traction - large boulders and rocks are rolled along the river bed.
Rivers need energy to transport material, and levels of energy change as the river moves from source to mouth. • When energy levels are very high, large rocks and boulders can be transported. Energy levels are usually higher near a river's source, when its course is steep and its valley narrow. Energy levels rise even higher in times of flood. • When energy levels are low, only small particles can be transported (if any). Energy levels are lowest when velocity drops as a river enters a lake or sea (at the mouth).
Deposition When a river loses energy, it will drop or deposit some of the material it is carrying. Deposition may take place when a river enters shallow water or when the amount of water decreases - for example, after a flood or during times of drought. Deposition is common towards the end of a river's journey, at the mouth. Deposition at the mouth of a river can form deltas - for example, the Mississippi Delta
The rivers course Small pebbles in river. River at its widest and deepest. Large rocks in the river. River getting wider and deeper Large boulders in the river. River narrow and shallow
3 stages of the river The journey of river from source (where the river begins) to mouth (where the river ends) is sometimes called the course of the river. The course of a river can be divided into three main sections: • upper course • middle course • lower course