1. Surface Water
Chapter 9

2. Surface Water Movement
Earth’s water supply is recycled

3. Surface Water Movement
Runoff- water flowing down slope on earth’s surface
Vegetation allows for greater infiltration of water into the ground.
Rate of precipitation can influence infiltration and runoff rates
Soil with high amounts of humus allow for greater infiltration.

4. Surface water movement
Open soil pores and compaction will influence infiltration rates
Gradual slopes allow for greater infiltration

5. Stream Systems
Precipitation that does not enter the ground usually flows quickly across the ground and eventually collects into small channels. As the amount of run off increases the channels widen, deepen, and become longer.

6. Watersheds and Divides
Watershed- all the land area whose water drains into a stream system.
Divide- high land area that separates watersheds

7. Stream Load Stream load- all the materials carried by a stream
Solution- dissolved material carried by water.

8. Stream Load
Suspension- particles held up by the turbulence of moving water.
Varies with volume and velocity

9. Steam Load
Bed Load- consist of sand, pebbles, cobbles that are too heavy to be suspended in the stream load. These materials may be “rolled” along the stream bed.

10. Stream Velocity
The ability of a stream to move material is dependent on the volume and velocity of water.
Discharge is a measure of the volume of water in a stream
Discharge = width x depth x velocity

11. Stream Velocity

12. Floodplain
Floods occur when water spills over the sides of a stream channel.
Floodplain- the broad flat area that extends out from a stream’s bank and is covered by water during flooding.

13. Stream Development
Swift fast-moving water at high elevations carve a narrow pathway called a stream channel.
The channel widens and deepens and is held in by the stream bank.

14. Stream Development
Stream activity erodes a path through sediment or rock.
A “v-shaped” valley forms and the stream cuts down until it reaches base level- the level at which it enters another stream or body of water.
After the stream cuts down then it starts to erode the sides of the stream bank and the valley becomes wider.

15. Stream Development

16. Stream Development
Meandering streams-form in gradually sloped wide u-shaped valleys. As the stream passes through this valley it will erode the sides of the stream bank and start to meander (bend or curve).
Water on the outside of a meander will flow quickly (erosion) and water on the inside of the meander will flow slowly (deposition).

17. Meandering

18. Ox Bow Lakes

19. Stream Deposition
Alluvial fan- fan shaped deposition feature when rapidly moving water suddenly slows down
Delta- triangular deposits that form as a stream enters a large body of water.

20. Stream Deposition

21. Stream Development
Rejuvenation- stream activity resumes down cutting because of uplift or base level lowering.

22. Lakes and Freshwater Wetland
Lakes- a depression in the surface materials of a landscape that collects and holds water.
Fill with water from streams, runoff, precipitation, and springs
Form from the movement of rivers (ox bow lakes), streams that become blocked, glacial remains.

23. Lakes undergo change
Lakes will fill with sediment over time and become part of the local landscape because of deposition.

24. Lakes undergo change
Eutrophication- process of lakes becoming rich in nutrients from the surrounding watershed changing the life that lives in the lake.

25. Freshwater Wetlands
Wetland- an area covered with water for a large part of the year.
Bog- not stream fed, rich in moss, acidic soil,

26. Wetlands
Marsh- occur along the mouth of streams and where extensive deltas occur, lush grasses, encourage wildlife

27. Wetlands
Swamps- low lying areas near streams, shrubs and trees

28. Wetlands Importance of wetlands Destruction of wetlands
Improve water quality
Habitat for migratory birds
Destruction of wetlands
Filled in for agriculture and urban growth
From the US lost 50% of its wetlands to development