16The Work of Rivers Processes of erosion: Hydraulic Action The force of the moving water causes erosion of the river bed and the banks of the river. The greater the speed and amount of water the greater the force.
17The Work of Rivers Processes of erosion: 2. Abrasion The rivers load is bounced and dragged along the river bed causing it to scrape and deepen the course of the river.
18The Work of Rivers Processes of erosion: 3. Attrition The rivers load is constantly colliding in the moving river water causing the load to break down into smaller pieces.
19The Work of Rivers Processes of erosion: 4. Cavitation As a river flows over the uneven river bed air bubbles travel up to the top of the river, pop and send ripples out towards the river banks. These ripples gently erode the rivers banks.
20The Work of Rivers Processes of erosion: 5. Solution Chemicals in the rivers water and rocks along the river course change the river chemically which reacts with and erodes various rocks along the way.
25Describing a feature F.E.E.D F: Feature (Name, erosion or deposition, stage it is found)E: Explain with at least one or two processes explainedE: Three examples, one IrishD: Clear 1/2/3 diagram/s to show how the feature is formed.
26Three features we will study Youth Stage = WaterfallsMature Stage = Meanders and Oxbow LakesOld age Stage = Deltas
27Features of the Youth Stage V – Shaped ValleysInterlocking SpursWaterfalls
28Interlocking spursA 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.
31Feature of Erosion Name Found Processes involved WaterfallYouth StageHydraulic ActionAbrasion
32WaterfallsfWaterfalls are features of erosion usually found in the upper course (youth stage) of a river.They are found in areas where a river is flowing over bands of hard and soft rock. The hard rock is slower to break down but the river can erode the soft rock much quicker. A band of hard rock lies on an area of soft rock. The river erodes the soft rock by the processes of hydraulic action (the force of the moving water) and abrasion (the scraping of the rivers load against the banks and bed). This causes a small notch to be formed into the soft rock which is eroded further into a drop over which the water falls. As the water falls over the drop there is a greater rate of hydraulic action and the rivers load also scrapes and deepens a hole in the bottom of the waterfall. This hole is called a Plunge Pool. The hard rock is slowly eroded and hangs over the edge called a Overhang. This is eventually worn down by the river and is carried away as the rivers load.e
33e d Examples of waterfalls include: 1 2 3 Diagram of a waterfall being formedd
34Victoria Falls, Zimbabwe Torc Waterfall, Killarney, Kerry ExamplesAngel Falls, VenezeulaVictoria Falls, ZimbabweTorc Waterfall, Killarney, Kerry
38Waterfall foe/sor= Feature of erosion….stage of river pp@bow= Weu=Waterfall erodes upstream(e) px2=Erosion, Process are hydrualic action and abrasionAoh/sr srw=Areas of hard/soft rock, soft rock weakerUcipp=Undercut collapses into plunge poolWaterfallNeisr=Notch eroded in soft rockPlunge pool at base of waterfallRfovd=River falls over vertical drop
39Can you put the labels below into the correct place on he diagram?
45Describing a feature F.E.E.D F: Feature (Name, erosion or deposition, stage it is found)E: Explain with at least one or two processes explainedE: Three examples, one IrishD: Clear 1/2/3 diagram/s to show how the feature is formed.
50Describing a feature F.E.E.D F: Feature (Name, erosion or deposition, stage it is found)E: Explain with at least one or two processes explainedE: Three examples, one IrishD: Clear 1/2/3 diagram/s to show how the feature is formed.
64Read Page 38-39 Name the river and the city of this case study? The city is between two physical areas…what are they?How is the city protected from flooding?What did the President do to the amount of money available for protection of the land?When did the disaster strike?What was the name of the hurricane?How many poor people could not leave the area?How many people drowned in this disaster?
65HEP: Hydro Electric Power Electricity made by the power of moving water