2. Catchment The area from which water drains into a particular drainage basin. Tributary A river which joins a larger river. Confluence The point at which two rivers join. Watershed The boundary dividing one drainage basin from another- a ridge of high land. What is a drainage basin? Source The upland area where the river begins. Mouth Where the river flows into the sea, or sometimes a lake.
4. The Long Profile of a River Changes in the river as it goes downstream from source to mouth.
5.
6. Valley & Channel Cross-Sections A Upper Course B Middle Course C Lower Course
7. What are the main features of a river? The fastest section of the river, as the channel is widest, with very smooth sides, and the greatest volume of water. The water has increased in speed as the channel widens and becomes smoother. Some boulders cause friction to slow it down a little. Relatively slow moving. Despite areas of fast flowing water, the large amount of material on the river channel bed means that friction will slow the water down. Velocity Deltas; flood plains; levees; meanders; ox-bow lakes Meanders; slip-off slopes; ox-bow lakes Interlocking spurs; waterfalls; V-shaped valley; gorges Features Mainly suspension and solution. Saltation, suspension and solution Traction and saltation Transportation Primarily cuts laterally as it has almost reached base level. The erosive energy of the river is almost totally concentrated on cutting sideways. Much deposition occurs. Continues to cut vertically. But it also begins to cut laterally as it gets closer to base level. Deposition occurs in the slower moving insides of meanders. Primarily vertical erosion, through attrition, abrasion and hydraulic action. Large boulders deposited and eroded in situ. Erosion & Deposition Wide, shallow valley, with large flood plains and meanders. The river channel is wide, deep and smooth sided. v-shaped valley remains with a wider valley floor and the river begins to meander across it. The river channel begins to widen and become deeper. Steep sided v-shaped valley. Thin river channel, deep in places Cross Profile Almost at sea level, very gently sloping towards its mouth Shallow slopes towards the mouth of the river Steeply sloping towards the lower sections of the river Long Profile Lower Course Middle Course Upper Course
8.
9. What processes occur in a river? There are 3 processes taking place in every river. These are: Erosion Transportation Deposition (The wearing away of the land) (The movement of eroded material) (The laying down of eroded material) There are also two other processes that shape the river valley. These are weathering and mass movement.
10.
11. Weathering & Mass Movement. The 3 main types of weathering are show below in the wrong order. Sort the statements out into the right order and copy these onto your sheet. Underneath copy out a definition of mass movement.
12.
13. Erosion Processes Match up the key word with the definition. Abrasion (Corrasion) is when the river is loaded with material in suspension and scours away at the river banks. (Sandpaper effect) Hydraulic Action is the shear force of the river impacting on the sides of the river banks. Corrosion is substances carried in solution such as acids. They dissolve rocks away over long periods of time. Attrition is when bed load collides into each other with the current flow and breaks down into smaller particles.
19. Upper valley characteristics “ V”shape valley, vertical erosion dominant Interlocking spurs Slumping and landslides - very active hill slopes Narrow, shallow channel, low velocity and discharge Large bed load derived from upstream and from valley sides
20. Narrow Channel Lots of tributaries High land so source of river Contour lines close together – steep valley sides Steep river gradient – contours close together Direction of flow shown by lower land No flood plain and V-shaped valley
22. Interlocking spurs A typical upper course V-Shaped valley with interlocking spurs , steep valley sides and active slope processes. The diagram below shows the formation of interlocking spurs.
23. Can you draw an annotated sketch of this valley to show how it is formed?
24. River load in upper course Boulders are large and semi-rounded, due to attrition within the load and abrasion with the stream bed and banks Why are they rounded?
31. Can you put the labels below into the correct place on he diagram?
32.
33. High Force waterfall, R. Tees Waterfalls create a gorge upstream as they recede, This is a steep sided valley with no floodplain.
34. Upper Course of a River Land use: Few settlements, Recreation, Farming, Forestry Steep valley sides Evidence of tributaries Reservoir High land Narrow channel and no floodplain
37. This is a picture of a river in its middle course. Can you recognise and explain the differences between the upper and middle course of a river?
38. Erosion is still an important process. The river is now flowing over flatter land and so the dominant direction of erosion is lateral (from side to side). The river has a greater discharge and so has more energy to transport material. Material that is transported by a river is called its load . Deposition is also an important process and occurs when the velocity of the river decreases or if the discharge falls due to a dry spell of weather. Processes operating in the middle course of a river
39.
40. A meander = a bend in a river Can you match up the characteristics below? There is little frictional drag from the bed and bank at this point and so the river can flow at this speed. Slowest flow Maximum depth of the channel. (Note the asymmetrical cross-profile) Fastest flow Because of the gentle slope, there is a lot of frictional drag and so therefore the river flows at this speed River cliff Formed on the outside bend of the meander due to erosion. Slip off slope A gently sloping area of land on the inside of a meander Deep water
42. Floodplain Deposits on the inner meander bend where there is low energy Erosion on the outer bend where there is faster flow. It creates a river cliff Slip-Off Slope Direction of meander migration
43. Can you match up the labels to the correct place on the diagram?
47. More gentle sloping valley sides Evidence of meanders Land use changes – more urban areas. Small floodplain begins to develop on either side of the river,
48. The Lower Course of a River Learning Objectives: To be able to describe and explain the formation of a flood plain, levees, delta and estuary.
53. This is a cross section of a floodplain. Can you draw a simple sketch of the diagram and the labels below and then annotate it to explain how it is formed? How a floodplain is formed leve é s clays and silts sands
54.
55.
56. Estuaries There are no large deltas around the coasts of the UK, instead the tidal mouth of a UK river is typically characterised with an estuary. Estuaries are wide river valleys flooded daily by the tide. At low tide, large expanses of mud and sandflats are exposed which are mostly composed of material deposited by the river, e.g Thames, Humber, Severn. Thames Estuary
