1. 8th Grade The Dynamic Earth (Module E)
Unit 1 Lesson 3 Erosion and Deposition by Water

2. Flowing water changes Earth’s surface
Unit 1 Lesson 3 Erosion and Deposition by Water
Flowing water changes Earth’s surface
Erosion is the process by which sediment and other materials are MOVED from one place to another.
Sediment: tiny grains of broken-down rock.
Deposition is the process by which eroded material is DROPPED. (usually downstream)
Happens when pull of gravity is more than force of flowing water or wind
Copyright © Houghton Mifflin Harcourt Publishing Company 2

3. https://s3. amazonaws. com/ck12bg. ck12

4. 1. Gradient – change in elevation over a certain distance
Unit 1 Lesson 3 Erosion and Deposition by Water
Factors that control how much sediment a stream moves -
1. Gradient – change in elevation over a certain distance
“Steepness” or “slope”
Steep gradient = more energy to carry soil
Copyright © Houghton Mifflin Harcourt Publishing Company 4

5. 2. Load - the materials carried by a stream.
Unit 1 Lesson 3 Erosion and Deposition by Water
2. Load - the materials carried by a stream.
The size of the particles in a stream’s load is affected by the stream’s speed.
Fast-moving streams = large particles and high erosion rate.
Slow-moving streams = smaller particles and low erosion rate.
Copyright © Houghton Mifflin Harcourt Publishing Company 5

6. 3. Discharge - amount of water that a stream carries
Unit 1 Lesson 3 Erosion and Deposition by Water
3. Discharge - amount of water that a stream carries
Increases after large storms and rapid snow melts.
As a stream’s discharge increases, its erosive energy, speed, and load increase.
Do the math! Page 31
Copyright © Houghton Mifflin Harcourt Publishing Company 6

7. What do you think? – read pg. 32-33
Unit 1 Lesson 3 Erosion and Deposition by Water
What landforms can streams create?
What do you think? – read pg
channel - the path that a stream follows
canyons and valleys
Copyright © Houghton Mifflin Harcourt Publishing Company 7

8. When rivers flood, sediments get deposited over flooded land
Unit 1 Lesson 3 Erosion and Deposition by Water
When rivers flood, sediments get deposited over flooded land
floodplain - flat area formed from many layers of deposited sediment. (Deposition!)
often very fertile – sediment contains nutrients
Meander video demo with sand -
Copyright © Houghton Mifflin Harcourt Publishing Company 8

9. Curves and bends in a stream channel are called meanders.
Moving water erodes the outside banks and deposits sediment along the inside banks.

10. sometimes a meander can be cut off, forming an oxbow lake.

11. - Water Erosion
Watch Grand Canyon formation video – Science Fusion History Channel resources

12. delta -fan-shaped pattern of deposited sediment IN WATER
Unit 1 Lesson 3 Erosion and Deposition by Water
When a stream empties into another body of water, its current slows and it deposits its load.
delta -fan-shaped pattern of deposited sediment IN WATER
Copyright © Houghton Mifflin Harcourt Publishing Company 12

13. alluvial fan - fan-shaped deposit that forms ON DRY LAND.
Unit 1 Lesson 3 Erosion and Deposition by Water
alluvial fan - fan-shaped deposit that forms ON DRY LAND.
Svalbard, in the Norwegian Arctic
Copyright © Houghton Mifflin Harcourt Publishing Company 13

16. What landforms can streams create?
Unit 1 Lesson 3 Erosion and Deposition by Water
What landforms can streams create?
What landforms can you identify in the image below? Explain how each type of landform formed.
Copyright © Houghton Mifflin Harcourt Publishing Company 16

17. Landforms made by groundwater erosion
Unit 1 Lesson 3 Erosion and Deposition by Water
Groundwater - water located within the rocks below Earth’s surface
-Acidic groundwater dissolves rock, forms caves
Sinkhole - circular depression when cave roof collapses
Stalactites and stalagmites - icicle-shaped deposits from water dripping from cracks in cave’s ceiling
Do digital lesson #9
Discovery education cave formation Mammoth Cave (7:51)-
Cool Cave formation and glaciers BBC -
Copyright © Houghton Mifflin Harcourt Publishing Company 17

18. What forces shape a shoreline?
Unit 1 Lesson 3 Erosion and Deposition by Water
shoreline - place where land and a body of water meet.
Ocean waves and currents, or streamlike movements of water, can erode and deposit materials.
Waves slow down as they approach a shoreline.
Copyright © Houghton Mifflin Harcourt Publishing Company 18

19. Waves strike headlands (pieces of land that project into the water) with MORE energy (=more erosion)
Waves striking
areas between
headlands have
less energy so
deposit materials.
Unit 1 Lesson 3 Erosion and Deposition by Water
Copyright © Houghton Mifflin Harcourt Publishing Company 19

20. Longshore currents
Unit 1 Lesson 3 Erosion and Deposition by Water
Currents that travel almost parallel to the shoreline very near shore.
-Caused by waves hitting the shore at an angle.
-As sand moves down a beach…
-upcurrent end is
eroded away
-downcurrent
end is built up
Longshore drift animation -
Copyright © Houghton Mifflin Harcourt Publishing Company 20

21. What forces shape a shoreline?
Unit 1 Lesson 3 Erosion and Deposition by Water
What forces shape a shoreline?
What might this beach area look like in the future?
Copyright © Houghton Mifflin Harcourt Publishing Company 21

22. Coastal landforms made by erosion
Unit 1 Lesson 3 Erosion and Deposition by Water
The rate at which rock erodes depends on the hardness of the rock and the energy of the waves.
Gentle waves - little erosion, strong waves (from storms) - increase rate of erosion.
Harder rock slows the rate of erosion - takes more wave energy to break the rock.
Soft rock erodes more rapidly.
Copyright © Houghton Mifflin Harcourt Publishing Company 22

23. Some landforms (p. 36 picture)
Unit 1 Lesson 3 Erosion and Deposition by Water
Some landforms (p. 36 picture)
sea cliff - waves erode and undercut rock to make steep slopes.
As a sea cliff erodes above the waterline, a bench of rock, called a wave-cut platform, can remain below the waterline.
sea caves – waves cut holes into weak or fractured rock
More erosion on sea caves makes sea arches and sea stacks.
Copyright © Houghton Mifflin Harcourt Publishing Company 23

24. What coastal landforms are made by erosion?
Unit 1 Lesson 3 Erosion and Deposition by Water
What coastal landforms are made by erosion?
What landforms can you identify in the image below? How did each landform form?
Copyright © Houghton Mifflin Harcourt Publishing Company 24

25. Coastal landforms made by deposition
Unit 1 Lesson 3 Erosion and Deposition by Water
beach -made up of material deposited by waves and currents.
The size and shape of materials on a beach depend on how far the material has traveled, the type of material, and how it is eroded.
sandbar - underwater or exposed ridge of sand, gravel, or shell material.
barrier island - long, narrow island, (usually made of sand) that forms parallel to the shoreline a short distance offshore.
Copyright © Houghton Mifflin Harcourt Publishing Company 25

26. Living on the Edge – read pg. 39
Unit 1 Lesson 3 Erosion and Deposition by Water
Living on the Edge – read pg. 39
Barrier islands are found all over the world.
Barrier islands can change shape and be eroded away by tides and large storms.
Barrier island erosion can be slowed down by using sandbags and other anti-erosion techniques.
Copyright © Houghton Mifflin Harcourt Publishing Company 26