Year 7 Geography- Rivers (B and P groups) Lesson 5 – Explain how a meander and an oxbow lake are formed Success criteria: I can define meander and oxbow lake I can explain how a meander is formed I can explain how a meander becomes an oxbow lake I can draw and label a series of diagrams showing meander formation Do now: 1. Rivers are used in agriculture for I… 2. When water is heated and rises into the air, it is called e… 3. Deposition (dropping material) happens when a river loses e… 4. What is formed when a waterfall retreats (moves backwards) upstream? 5. Name a job in the tertiary sector 6. Challenge: abrasion is when… Meanders: Start by watching this video: https://www.bbc.co.uk/bitesize/clips/zvm3cdm A meander is a bend in a river It starts with a slight bend. The The fast water erodes the Continued erosion and water moves faster on the outside of the bend. The deposition makes the bend outside of the bend and slower slower water deposits material bigger. on the inside of the bend. on the inside of the bend. Complete the sentences below: A meander is __________________________________________________________________________________ A meander starts with a……………… The fast water…………….……………… Continued e…………………………….on …………………………………………………... Water moves the……………………………of the bend the……………………………of the bend and fastest…………………..………………………………………... d………………………………..on the Water moves slowest……………………………………... The slow water…………….……………. material on …………………………………of the bend the………………………….. of the bend makes………………………………………... Challenge: suggest two types of erosion that occur on the outside of the bend ________________________________________________________________________ ________________________________________________________________________ Oxbow lakes: Start by watching this video: https://www.bbc.co.uk/bitesize/clips/zrhc87h An oxbow lake is a U shaped lake near a river Over time, erosion makes the Eventually the neck of the As less water is flowing through meander bend larger and larger. meander breaks through and the the meander, the energy is The neck of the meander water takes the most direct reduced. Material is deposited, narrows. route, avoiding the meander. blocking off the meander and creating an oxbow lake. Complete the sentence starters on the next page. An oxbow lake is _______________________________________________________________________________ Continued…………………………makes the Eventually the……………….…..of the meander As no water is flowing through the meander, bend…………………………………….. As a result breaks through and the water takes the the energy……………. the……………………of the meander most direct route avoiding …………………………………………………... gets…………………………… the……………………………….. As a result material is…………………. ………………………………………………….., blocking off the………………………….. and creating an………………………….. ………………………………………………….. Exit ticket: What is the name of the landform in the picture? ____________________________ What is going to happen to that landform over time? ____________________________ Does water flow fastest on the inside or the outside of the bend? _____________________________ Where is material dropped (deposited), the inside or the outside of the bend? ______________________________ Challenge: On paper, and without looking at your notes, draw and label the three stages of meander formation. .