Presentation is loading. Please wait.

Presentation is loading. Please wait.

Vincent Raeburn Linlithgow Academy Malcolm McDonald Bathgate Academy Linlithgow Academy.

Similar presentations


Presentation on theme: "Vincent Raeburn Linlithgow Academy Malcolm McDonald Bathgate Academy Linlithgow Academy."— Presentation transcript:

1 Vincent Raeburn Linlithgow Academy Malcolm McDonald Bathgate Academy Linlithgow Academy

2 How rivers erode HYDRAULIC ACTION The force of the water weakens and breaks up the rocks ABRASION The material carried in the river wears away the river bed ATTRITION As the pebbles carried by the river crash into each other,they become smaller and rounder SOLUTION The water in the river dissolves the minerals in the rocks

3 How rivers transport Rolling stones along the river bed.( needs lots of energy) TractionSuspension Clay sized particles are carried along by the river flow Saltation Sand sized particles bounce along the riverbed Solution Some minerals are dissolved by the riverwater river flow

4 River Basin Source of River Aye Confluence of River Aye and tributary Tributary of River Aye Flood plain Mouth of River Aye Sea Estuary of River Aye Watershed of River Aye (boundary between basins)

5 Source of river Upper Course Middle Course Lower Course

6 FEATURES OF THE UPPER COURSE V-SHAPED VALLEYS WITH INTERLOCKING SPURS POT HOLES ON RIVER BED WATERFALLS AND RAPIDS

7 Formation of a waterfall Soft rock Hard rock Steep sides ( gorge ) Vertical erosion Forms plunge pool Undercutting erodes the softer rock forming an overhang The overhang Eventually collapses The process starts again Eroded rock Waterfall Retreats upstream

8 PLUNGE POOL UNDERCUTTING OF SOFT ROCK OVERHANG WATERFALL RETREATS.. UPSTREAM..

9 The River Avon has smoothed off parts of this hard igneous rock... What is this process called?

10 MEANDERS Flood plain Meanders © Used with the permission of the Geological Survey of Canada, Natural Resources Canada Available at – Terrain Science Divisionhttp://sts.gsc.nrcan.gc.ca Most erosion on the outside of the bend.. Fastest flow Possible break through point Possible ox-bow lake

11 Fastest currentslowest current Outer bank Is undercut Slip off slope ( river beach ) Deposition of Sand and shingle Deepest part of the river Bank will collapse Small river cliff River bend

12 Formation of an ox-bow lake The meanders change shape through time At the bends the river flows faster at the outside The bends migrate Sideways leaving deposits on the inside Of the bend The erosion makes the Meanders more pronounced Small river cliff is formed Most erosion Most deposition (Slip off slope) Some bends get closer and closer The neck gets narrower and narrower Eventually during a period of heavy river flow it cuts through The river now follows the new route The old meander Is left as a small lake (OX - BOW lake) © Used with the permission of the Geological Survey of Canada, Natural Resources Canada Available at – Terrain Science Division

13 Want to see that again ?

14 NARROW MEANDER NECK FUTURE OX-BOW LAKE

15 Gentle valley sides Flat floodplain Layers of silt Deposited during floods Coarse material Forms natural levees River is actually flowing above The floodplain !! Levees is often artificially strengthened

16 CharacteristicsUpper CourseMiddle CourseLower Course Slope Width Depth Straightness Load Main work Valley width Type of load usually steep narrow shallow winding little large/small angular erosion transportation quite steep quite wide quite deep meandering some medium/small rounded Transportation narrow gentle quite wide wide deep big meanders lots small+ rounded transportation deposition wide

17 Reproduced with kind permission of Ordnance Survey © Crown Copyright NC/03/18990 tributaries ox-bow lake meander V shaped valley Steep Valley sides Flood plain


Download ppt "Vincent Raeburn Linlithgow Academy Malcolm McDonald Bathgate Academy Linlithgow Academy."

Similar presentations


Ads by Google