The Flow of Freshwater

1. The Flow of Freshwater

2. How is the Earth’s Water Distributed?

3. How does this freshwater flow across the surface of the earth?

4. RIVERS • Rivers? Streams? Creeks? They are all names for water flowing on the Earth's surface • Where does the water come from to fill these?

5. The Water Cycle • The continuous movement of water from the ocean to the atmosphere to the land and back to the ocean.

7. Model of river running from the mountains to the sea.

8. Parts of a River System

9. Continental divide of the United States • River systems are divided into regions called watersheds or drainage basins • This is the area of land that is drained by a water system. • River systems are separated from each other by areas of higher ground called a divide.

10. Drainage of river systems

11. Cross section of a River

12. Definitions • Tributary: a stream that flows into a lake or into a larger stream • Channel: the path that a stream follows • Bed: the bottom of the stream • Load: the materials carried by the stream • Bed load: the materials carried along the bottom of the stream • Suspended load: materials carried in suspension (floating in the water) • Dissolved load: materials carried in solution, they usually cannot be seen.

13. Bed flow and direction

14. How do these rivers form? • Erosion: the process by which soil and sediment are transported from one location to another. • It can be transported by wind, water, ice or gravity.

15. What is this and how did it form?

16. The Grand Canyon and it was all formed by EROSION !!

17. STREAM EROSION • As a stream forms it erodes soil and rock to make a channel. • When it first forms, it is usually narrow and steep. Over time, the stream transports more rock and soil downstream and makes the channel wider and deeper. • When streams become longer and wider they are called rivers.

18. Factors that influence a stream’s ability to erode • Gradient: measure of the change in elevation over a certain distance (how steep it is) • Discharge: amount of water that a stream or river carries in a given amount of time. • Load: the materials carried by the stream.

19. 3 stages of a River • Youthful River • Mature River • Old River • Rejuvenated River

20. Characteristics of a Youthful River • Channel is eroded deeper rather than wider • Water flows quickly because it has a steep gradient • Has rapids and waterfalls • Have very few tributaries • HIGH erosive energy

21. Youthful RiverYosemite National Park

22. Characteristics of a Mature River • Erodes channel wider rather than deeper • Does not have a steep gradient • Few rapids or waterfalls • Has many tributaries • Has more discharge than a youthful river • Has meanders

23. Meandering Stream • Mature rivers curve back and forth. The bends in the river are called meanders.

24. Mature River

25. Characteristics of an Old River • Low gradient and low erosive energy • Instead of widening and deepening its banks, the river deposits its soils in and along its channel • Have wide flat flood plains (valleys) • Has few tributaries

26. Old River

27. Rejuvenated River • A river whose gradient (steepness) has been raised by tectonic activity (movement of the crust of the earth).