1. Chapter 11
Rivers & Groundwater

2. 11.1 Notes – The Active River Water Cycle
water cycle – the continuous movement of water from water sources, into the air, on to land, into the ground, and back to water sources
evaporation – liquid water from water sources changes into water vapor in the air due to heat from the sun
condensation – water vapor in the air changes into liquid droplets, forming clouds

3. 11.1 Notes – The Active River Water Cycle
precipitation – rain, snow, sleet, or hail falls from the clouds on to the Earth’s surface
percolation – gravity pulls water that is already in the ground through the soil back to the water sources

4. 11.1 Notes – The Active River Water Cycle
runoff – water flows across the ground or falls from the clouds and collects in rivers or streams

5. 11.1 Notes – The Active River Water Cycle
What main source of energy drives Earth’s weather systems?
Solar radiation (from the sun)
What drives the water cycle?
The sun

6. weathering – the process by which sediment is broken off rock

7. erosion – the process by which sediment is picked up and moved to a new location

8. Erosion What are the 5 agents of erosion? Wind
Water (rivers, streams, ocean waves)
Ice (glaciers)
Precipitation (rain, snow, sleet, & hail)
Gravity (causes landslides)

9. Erosion How can erosion happen fast? How can erosion happen slowly?
A river overflowing leaving the side of the banks muddy
How can erosion happen slowly?
Grand Canyon – the river eroding the surface of the Earth slowly overtime

10. deposition – the process by which sediment is dropped due to lack of speed

11. Mountain Changes What can change the shape of a mountain?
Precipitation – rain, snow, sleet, and hail
Runoff – forming rivers and streams
Water flowing down hill can carry sediment because of gravity
Weathering, erosion, & deposition
What will form at the top of a mountain during precipitation?
A stream with a few bends

12. 11.1 Notes – The Active River
load – the rocks and soil (sediment) carried in a stream’s water
Why would a river carry more of a load?
Because it has more water, because it is flowing fast, because it is on a hill or mountain, because water in a river can rise during precipitation
3 types of loads:
bed load – large pieces of sediment like boulders and pebbles
suspended load – small pieces of sediment like small rocks and sand – this makes the water look muddy
dissolved load – dissolved material like sodium and calcium – this makes the water look clear

13. 11.1 Notes – The Active River
meander – a curve or bend in a river or stream
What happens at a meander?
On the outside of the curve the water speeds up and erodes sediment
On the inside of the curve the water slows down and deposits sediment
channel – the path that a stream follows

14. Characteristics of the 4 stages of a river
youthful river – fast, waterfalls, steep gradient, bedload, deep not wide, erosion happens quickly

15. Characteristics of the 4 stages of a river
mature river – deep, slow, wide, not very steep, meanders, suspended load

16. Characteristics of the 4 stages of a river
old river – slow, wide, shallow, floods, meanders, dissolved load, a lot of sediment deposits, many times forms oxbow lakes
oxbow lake – formed by an increase in the flow of water in a river causing the river to change course

17. Characteristics of the 4 stages of a river
rejuvenated river – land is raised by tectonic plates, steep cliffs above the river, river erodes valley floor

18. 11.1 Notes – The Active River
Why would one river have more sediment than another river?
More water = more sediment
What would give a river more water?
precipitation
What are two ways that beaches get sand?
Waves slow down and weather rocks depositing sand
Rivers end at the ocean creating a delta (deposited sediment)

19. 11.1 Notes – The Active River
Why does water flow downhill on a mountain?
Gravity – water always flows from higher elevations to lower elevations
How do you know if a river has recently flooded?
There is wet mud on the ground

20. 11.1 Notes – The Active River
How could two mountains with a small stream in between become flat 50 million years later?
precipitation
What happened to the sediment?
eroded by the stream and deposited in the ocean
Why would a river change course?
floods

21. 11.2 Stream and River Deposits
alluvial fan – fan shaped deposits that form on dry land when a river or stream loses speed
delta – fan shaped deposits that form at large bodies of water such as the ocean when a river or stream loses speed
This is one way beaches more sand.

22. 11.2 Stream and River Deposits
floodplains – an area along a river that forms from sediment deposited when a river overflows its banks
Where would you find a lot of floodplains?
On old rivers because they flood a lot