Use your learning from your lesson on V-shaped valleys and interlocking spurs formation to complete this short quiz.

A narrow, steep-sided valley formed as a result of rapid erosion by a stream or river is known as a...

V-shaped valleys are created by...

The material transported by a river is known as its...

Ridges of high ground that project into V-shaped valleys. They occur on alternative sides of a valley and fit together rather like the teeth of a zip fastener, are known as...

In the upper course, rivers do not have enough power to...

V-shaped valleys and interlocking spurs - quiz

﻿Hello, it's Mr, Burton. Welcome to this lesson in the rivers unit of work. In today's lesson, we are focusing our attention on the upper course, and we are going to look at the spectacular landforms of waterfalls and how they form. So you need, as ever, a pen, a pencil, and something to write on or a laptop. And when you're ready and somewhere quiet where you can focus, hit play and we will start property. Hi, my name is Mr. Burton. Welcome to this lesson in the rivers unit of work. In today's lesson, we will be learning about waterfalls and gorges and their formation in the upper course of rivers. So for today's lesson, as ever, you will need a pen, a pencil, and then either an exercise book or a piece of paper to write on, so please pause the video now to gather together those materials so you are ready fully for the lesson and hit play when you're ready to begin. So if you remember, in terms of a river's long profile, it's split into three, three courses or three sections, and they're named the upper course, the middle course, and the lower course. In the upper course, we have landforms formed by erosion, in the middle course, we have landforms formed by erosion and deposition, and in the lower course, we have landforms formed just by deposition. We're going to look at waterfalls and gorges today, which are found in the upper course and are therefore formed by erosion. So the first key term for you to write down is waterfall, which is a sudden fall of water over a steep drop, so please pause the video here to note down that key term. So a waterfall occurs as water drops from a height when a river or stream flows over a steep drop, and there's an image on the right of quite a small waterfall. I imagine lots of you have seen waterfalls in a real life. They range from a small drop to a drop of hundreds of metres. So the first mini task I'd like to do, please pause the video here, have a look at this OS map extract. You need to give three bits of evidence to show that this is the upper course of a river, so this map extract comes from the upper course of a river. Please pause the video here and note down three bits of evidence which give away the fact that it's from the upper course of a river. Pause the video here. Okay, here are three things I think you could have said. So the contour lines are very close together, which shows this is an area of steep slopes, and therefore in the upper course, or you could have said spot heights show that this area is up to 382 metres high and therefore typical of an upland upper course area. Also, many waterfalls are marked on the map, which again are typical features of an upper course of a river, so please pause the video here to correct your work. So two more bits of key terminology for you today to write down, please. So undercut, to cut or wear away the part below a rock, leaving it unsupported. A gorge is a steep sided valley left behind when a waterfall retreats upstream. So if you could pause the video here, please, to note down both of those key bits of terminology. I'm going to explain how a waterfall forms in four stages. The first time around, I suggest you just listen and watch the explanation, but then I suggest that you rewind it and draw your own mini sketch diagrams to explain what's happening at each stage. So stage one, we've got waterfalls forming in the upper course where the river flows over hard and soft rock, and you can see that in the image on the right hand side. In stage two, soft rock erodes quicker than hard rock, often by hydraulic action, which creates a plunge pool because some of the soft rock has been carved out and you can see the soft rock there. This undercuts the hard rock and the hard rock now overhangs, so you can see in the image, there's a slight overhang. Phase three, as the overhang is left unsupported, it will eventually collapse, and you can see that from the image. The rocks fall into the plunge pool and act to erode the plunge pool further by abrasion, and you can see some of the fallen rocks stay in the plunge pool, carving out the plunge pool to make it even bigger. Step four, over time the sequence and processes repeat and more erosion and undercutting causes further collapse. The waterfall retreats, that means moves backwards, upstream, leaving a steep sided gorge, so you can see the direction of retreat there on the diagram. A gorge sometimes is a bit hard to picture, so I've given you a slightly different view now using a different image to show you that as that waterfall retreats, it leaves behind this very narrow, steep sided valley, which is known as a gorge, and gorges can take thousands of years to form. Here is an image of a very famous waterfall in the UK. This is High Force on the River Tees. As a quick check, can you put the following statements into the correct order? So read the statements A, B, C, D, and then order them into the correct sequence, so please pause the video here to have a go at that. Okay, here is the correct order. Let's go through it. So first one is B, a river flows over hard and soft rock. The next one is D, soft rock erodes quicker than hard rock, creating a plunge pool and an overhang. Thirdly, we've got A, the overhang collapses and the plunge pool gets bigger. Finally, number four, we have C, the process repeats and the waterfall retreats upstream to leave a gorge. Well done if you got all of those correct. Though your final task today is an extended written one, you need to explain the formation of a waterfall and a gorge for four marks, and you've got two bits of success criteria. All the key terms from the box below are included in your answer and the answer is in the correct order or sequence. And the words that I want you to include are as follows, hard rock, soft rock, quicker, hydraulic action, plunge pool, undercuts, overhangs, unsupported, collapse, repeats, upstream, and gorge, so please pause the video here to explain the formation of a waterfall and gorge using the instructions on screen now. Here is a teacher model. You can use this perfect answer to mark your own response. So firstly, there was soft rock on top of hard rock. The soft rock erodes quicker due to the sheer force of the water as it falls, which is called hydraulic action. This creates a plunge pool in the soft rock. This undercuts the hard rock, so the hard rock overhangs. As a result, the hard rock is unsupported, so it collapses. The process repeats and the waterfall retreats upstream, leaving behind a gorge. So please use this now to mark and improve your own response. That brings us to the end of today's lesson, so well done for the fantastic learning you have achieved. Before you close this lesson, make sure you have completed the exit quiz to test and consolidate your learning. Next lesson, you will be looking at some landforms which form in the middle course of a river. I hope you join us for that.

Use your learning from your lesson on waterfall formation to complete this short quiz.

A gorge is a...

The pool at the bottom of a waterfall is known as a...

When the bottom of a rock is worn away leaving it unsupported it is said to be...

A waterfall is typically found in the...

A waterfall is formed by...

How do waterfalls form? - quiz

In this lesson, we will learn about how erosional processes create waterfalls and gorges.

Geography

Y10 Geography

Key Stage 4

Year 10

Landforms of erosion: waterfalls and gorges

Rivers

UNIT

What are river long and cross profiles?

How do rivers erode, transport and deposit their load?

Landforms of erosion: V-shaped valleys and interlocking spurs

Landforms of erosion and deposition: meanders and oxbow lakes

Landforms of deposition: levees, floodplains and estuaries

Landforms in a UK river valley: The River Tees

How does the river drainage basin system work?

What are the human and physical factors that increase flood risk?

What are hydrographs and what do they show?

How can rivers be managed using hard engineering strategies?

Soft engineering river management (Part 1)

Soft engineering river management (Part 2)

A UK Flood Management Scheme: Oxford

Name the landform shown in this map.

Which course of the River Tees is being shown in this map?

Impermeable soils and rock...

Deforestation decreases...

A hydrograph shows...

The following question is about hydrographs

Lag time is...

Deforestation reduces...

The line of fastest flow in a river is called the...

Lateral erosion is...

In the upper course, the river is...

In the middle course, what is the dominant method of erosion?

As a river moves downstream, discharge...

Soft engineering is...

An advantage of flood warning and preparation is that...

Floodplain zoning is...

During the 2007 Oxford floods...

A negative, social issue about the flood management scheme in Oxford is...

Levees are...

Estuaries form at the...

Floodplains...

An advantage of planting more trees to help reduce the effect of flooding is that...

Lesson overview:Landforms of erosion: waterfalls and gorges

Rivers: