We think you have liked this presentation. If you wish to download it, please recommend it to your friends in any social system. Share buttons are a little bit lower. Thank you!
Presentation is loading. Please wait.
Published byRory Kimball
Modified over 2 years ago
© Boardworks Ltd 2005 1 of 34 These icons indicate that teachers notes or useful web addresses are available in the Notes Page. This icon indicates the slide contains activities created in Flash. These activities are not editable. For more detailed instructions, see the Getting Started presentation. 1 of 34 © Boardworks Ltd 2005 The Middle and Lower Course of a River
© Boardworks Ltd 2005 2 of 34 What are the main processes that operate in the middle and lower course of a river? What landforms are found in the middle and lower course of a river? How are these landforms created? Learning objectives
© Boardworks Ltd 2005 3 of 34 What are the main processes that operate in the middle and lower course of a river? 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. Why do you think that a river in the middle and lower course has a higher discharge than near the source?
© Boardworks Ltd 2005 4 of 34 How is material transported downstream?
© Boardworks Ltd 2005 5 of 34 How is material transported downstream? SaltationSolutionTraction Suspension Boulders and pebbles are rolled along the river bed at times of high discharge. Sand sized particles are bounced along the river bed by the flow of water. Fine clay and sand particles are carried along within the water even at low discharges. Some minerals dissolve in water such as calcium carbonate. This requires very little energy.
© Boardworks Ltd 2005 6 of 34 How is material transported downstream?
© Boardworks Ltd 2005 7 of 34 How is material transported downstream?
© Boardworks Ltd 2005 8 of 34 Do you know the difference between erosion and transport?
© Boardworks Ltd 2005 9 of 34 The River Conwy has deposited material in this section of its course. Suggest reasons why this has happened. Deposition
© Boardworks Ltd 2005 10 of 34 What are the main processes that operate in the middle and lower course of a river? What landforms are found in the middle and lower course of a river? How are these landforms created? Learning objectives
© Boardworks Ltd 2005 11 of 34 What landforms are found in the middle and lower course? 1)Meanders 2)Oxbow Lakes 3)Flood plains and Leveés 4)Deltas DEPOSITION created these landforms DEPOSITION and EROSION create these landforms
© Boardworks Ltd 2005 12 of 34 What are the main processes that operate in the middle and lower course of a river? What landforms are found in the middle and lower course of a river? How are these landforms created? Learning objectives
© Boardworks Ltd 2005 13 of 34 Meander = a bend in a river
© Boardworks Ltd 2005 14 of 34 Water is pushed to the outer bend. This reduces friction with the bed and banks. So the river has more energy for transporting material which can erode the outside bank via abrasion. Meanders As the course of a river approaches its middle stages it flows over flatter land. Lateral erosion dominates as the river swings in large bends known as meanders. Meanders constantly change their shape and position.
© Boardworks Ltd 2005 15 of 34 Explain the following hypotheses: The fastest current is always on the outer bend. All meanders have river cliffs and slip-off slopes. Meanders
© Boardworks Ltd 2005 16 of 34 A cross section through a meander
© Boardworks Ltd 2005 17 of 34 A cross section through a meander
© Boardworks Ltd 2005 18 of 34 Meander bend on the River Conwy A B Explain why there is more deposition at A rather than at B. A cross section through a meander
© Boardworks Ltd 2005 19 of 34 Oxbow lakes
© Boardworks Ltd 2005 20 of 34 Meander neck becomes smaller new course of the river oxbow lake When the river floods it breaks through the thin meander neck and the river takes the easier, straight course. This leaves the meander loop cut off as an oxbow lake. Over time, the oxbow lake will become colonised by vegetation. Explain the formation of an oxbow lake
© Boardworks Ltd 2005 21 of 34 Explain the formation of an oxbow lake
© Boardworks Ltd 2005 22 of 34 Floodplains
© Boardworks Ltd 2005 23 of 34 Floodplains and leveés are formed by deposition in times of river flood. The rivers load is composed of different sized particles. When a river floods it deposits the heaviest of these particles first. The larger particles, often pebble-sized, form the leveés. The sands, silts and clays are similarly sorted with the sands being deposited next, then the silts and finally the lightest clays. Every time the river floods deposition builds up the floodplain. Floodplain formation
© Boardworks Ltd 2005 24 of 34 This is a cross section of a floodplain. Draw a simple sketch of the diagram and annotate with the following labels: leveésclays and silts sands Floodplain formation
© Boardworks Ltd 2005 25 of 34 Deltas are found at the mouth of a river, where the river meets the sea. At this point the river is carrying too much load for its velocity and so deposition occurs. The top of the delta is a fairly flat surface. This is where the coarsest river load is dropped. The finer particles are carried into deeper water. The silt is dropped to form a steep slope on the edge of the delta while the clay stays in suspension until it reaches the deeper water. Delta formation
© Boardworks Ltd 2005 26 of 34 Delta formation
© Boardworks Ltd 2005 27 of 34 The Grand Rhône The mouth of the Rhône
© Boardworks Ltd 2005 28 of 34 The area of the Rhônes delta is known as the Camargue. It is an example of an arcuate or fan delta. It has been created because of the vast amounts of sediment deposited over the years and the low tidal range of the Mediterranean. The Rhônes delta – the Camargue Draw and label a diagram of the Rhône delta and explain its formation.
© Boardworks Ltd 2005 29 of 34 Name the river landform shown in this aerial photograph. What else can you identify? How can you tell that this is not the upper course of a river? Techniques – interpreting aerial photographs
© Boardworks Ltd 2005 30 of 34 Examination question A B C Study the photograph below: Name the 3 features labelled A, B and C (3) Choose one of the features and explain its formation. You may use diagrams to help you.(6)
© Boardworks Ltd 2005 31 of 34 The landforms of a river Which landforms are missing? Why?
© Boardworks Ltd 2005 32 of 34 Landforms are primarily caused by: processes of erosion processes of deposition a mixture of erosion and deposition deltasmeandersfloodplains waterfalls leveés oxbow lakes rapids v-shaped valleys interlocking spurs Which of the following landforms are the result of a mixture of erosion and deposition? The landforms of a river
© Boardworks Ltd 2005 33 of 34 How much do you know about rivers?
© Boardworks Ltd 2005 34 of 34 Key ideas Processes of erosion, transport and deposition operate to create the landforms of the middle and lower course of a river. There are four types of transport: traction, saltation, suspension and solution. The main direction of erosion is lateral. Erosion and deposition contribute to the formation of meanders and ox-bow lakes. Deposition is the main process contributing to the formation of flood plains, leveés and deltas.
© Boardworks Ltd of 34 River landforms in the Middle and Lower course Aim: To understand how meanders form in the middle section and ox bow lakes,
The lower course of the river LO: I can describe and explain he formation of ox bow lakes. I can describe and explain he formation of flood plains. I can.
The middle course of the river Learning objective To be able to explain the characteristics of the middle course of the river To be able to able landforms.
TRACTION SALTATION SUSPENSION SOLUTION Particles of rock are dissolved in the water and carried along without being seen. Large boulders and rocks are.
1. TarmacConcreteGrass 2. Planting trees Dam building Heavy Rain 3. LakeVegetationDeforestation 4. Evaporation Condensation Urbanisation.
The Middle and Lower Course of a River Starter: 1.Draw a simple diagram of the river cross section at the following areas: Upper course Middle course 2.Now.
Rivers. Long Profile Height above sea level in meters Distance from sea in Kms. Source. Upland stream. Lowland.
Aim: To develop a knowledge and understanding of Rivers in the landscape By the end of the lesson I should know: New terminology for important parts of.
River landscapes and processes Geography CCEA GCSE 2009.
What is the long river profile? The gradient is less steep than in the upper course. The valley gets wider and flatter. Erosion is more lateral (or.
© Boardworks Ltd of 42 The River Conwy has deposited material in this section of its course. Suggest reasons why this has happened.
Rivers. Common River Terms Source – The place where a river begins. Course – The route the river takes to the sea Tributary – A small river that joins.
1 River features? Are facial features the same thing for rivers?
Erosion and Deposition. Running Water is the most effective agent of erosion. Erosion is the process by which earth materials are moved by natural agents.
Objectives Describe how surface water can move weathered materials. Explain how a stream carries its load. Describe how a floodplain develops. Surface.
© Boardworks Ltd of 26 These icons indicate that teacher’s notes or useful web addresses are available in the Notes Page. This icon indicates the.
Running water: The major force of erosion acting on Earth today. If it weren’t for the mountain- building activity of plate tectonics, Earth would be completely.
Landforms in the Lower Course Meanders and Ox-bow Lakes.
Rivers: Profiles & Landforms Higher Geography The Hydrosphere.
EROSION- The transport of weathered materials….
TRANSPORTATION & DEPOSITION in a Stream System.
Erosional and depositional river landscapes LS: Apply knowledge of Erosional processes to understand how erosion forms river landscapes. Describe the formation.
Unit 1.3B_4 River Landforms. Now you know a bout the processes that enable the river to change What does the river look like?
3. River Profiles and Processes WALT To understand the 3 main courses of a river and their characteristics. Understand the main processes which happen.
R IVER I NVESTIGATION – THE T HEORY !. W HAT IS A D RAINAGE B ASIN ? A drainage basin is an area of land drained by a river and its tributaries. Its boundary.
The Hydrological (Water) Cycle The River System – the drainage basin. A river system is an open system. An open system has inputs, processes and outputs.
Rivers Location Profiles Processes Landforms Thames Spey Clyde Shannon Tees Ouse Tay Severn Trent Forth Main UK.
Longitudinal profile Fluvial/River- Areas The path the river follows from its source to mouth is known as the river's course. When studying rivers we.
As you know from Chapter 2, weathering is the breakdown of rocks into smaller pieces. So what is erosion? Erosion is the movement of the broken or weathered.
The Global Hydrological Cycle. Inputs: Precipitation (eg. Rain, hail, snow, sleet, dew, fog) Flows: Throughflow, Groundwater Flow, Overland Flow.
Introduction to Rivers. Where the river begins… The start of a river is called its source. Large portions of the world's largest rivers begin in hollows.
WHAT CAN YOU REMEMBER? land ocean 4) _________ 5) __________ 1) ________ 2) _________ 3) _________ 6) ________.
River Transportation and Deposition. Load Suspended load Dissolved load Bed load Capacity Competency Sec Page Deposition.
Vincent Raeburn Linlithgow Academy Malcolm McDonald Bathgate Academy Linlithgow Academy.
Erosion The transport of earth materials from one place to another. AGENTS –Running water (MOST ACTIVE AGENT) –Moving air (Wind) –Glaciers FORCE driving.
What happens to rainfall when it hits earth???? Some evaporates Some evaporates Some is absorbed and becomes ground water Some is absorbed and becomes.
Water Erosion Chapter 3 Section 2. Standard S 6.2.a – Students know water running downhill is the dominant process in shaping the landscape S 6.2.a.
“Hurricane force winds batter the UK. “ (bbc, 12 feb) Why is this not a hurricane though?
From RegentsEarth.com win.
Stream Erosion and Transport Erosion: Hydraulic action – erosion caused by the movement of water against stream sediment Abrasion – erosion caused by particles.
The River Course Features of the Upper Course Potholes Waterfalls Rapids Features of the Middle Course Flood Plain Meanders Features of the Lower Course.
EXIT CHAPTER CHAPTER 13.1 Streams and Rivers 13.2 Stream Erosion and Deposition 13.3 River Valleys 13.4 Flood Plains and Floods CHAPTER OUTLINE Surface.
Water Erosion “We’re changing Earth’s Surface!” A. Stream Erosion 1. Running Water 2. Energy 3. The water cycle -Most effective agent in wearing down.
AIM: What is a stream/river? Do Now: Answer the following questions in your notebooks. Where does the water come from that fills streams and rivers? Where.
Potholes are formed due to stream or river erosion which initiates by simple plucking out at the riverbed by hydraulic action. These are variously.
What landforms and features are associated with the lower course of a river? LO: To investigate the main features in the lower course of the river.
Depositional Features. Deltas Deltas occur where a river that carries a large amount of sediment meets a lake or the sea. This meeting causes the river.
These two agents: erosion and deposition are the most important agents that affect weathered materials. Erosion involves the physical removal of weathered.
Module 1 : The Fluvial Environment Fluvial: Relating to or occurring in a river.
© 2017 SlidePlayer.com Inc. All rights reserved.