1. Surface Water
Chapter 9

2. Surface water movement: Water (Hydrologic) Cycle
Earths water supply is constantly recycled

3. The Water Cycle The Sun provides energy for the water cycle.
Radiation from the Sun causes water to change to a gas called water vapor.
The process of water vapor changing to a fluid is called condensation.

4. Precipitation falls to Earth’s surface in the form of rain, snow, sleet, or hail.
Water then flows downslope along Earth’s surface which is called Runoff.

5. Runoff may reach a stream, river, or lake, may evaporate
or may accumulate into puddles and eventually seep into
the ground.

6. Water that seeps into the ground becomes groundwater.
For water to enter the ground, there has to be large pores or spaces in the ground.

7. Fate of water: Run off or Seep
Certain characteristics will determine whether not water will either seep into or become runoff
1) Vegetation
Vegetation allows for loose soil
Loose soil allows water to enter ground

8. Fate of water 2) Rate of precipitation Heavy: Light:
Water falls too quickly and becomes runoff
Light:
allows water to gently slide through

9. Fate of Water 3) Soil Composition Effects the waters holding capacity
Decayed organic matter (humus)
Creates the pores in soil which retains water
Minerals
Clay – fine mineral which clump together
Few Spaces
Sand – large pores-allows water to move through it.

10. Fate of Water
4) Slopes
Steep: allows for high runoff & little absorption
Little: low runoff and high absorption

11. Formation of Stream systems
Precipitation that does not enter the ground usually runs off the surface quickly.
Surface water flows in thin sheets and eventually collects in small channels
Runoff increases, channels widen and become deeper and longer
Channels fill up again each time with rain
Channel can become a stream

12. Streams Some streams flow into lakes and oceans.
Tributaries flow into other streams.

13. Streams
A large stream = River. All of it’s tributaries make up a stream or river system.
Small streams are called brooks or creeks.

14. Water sheds (Drainage Basin):
Land where all water drains into a stream
Divide
High land area that separates watersheds

15. Stream Load All the materials that the stream carries
There are 3 ways that a stream carries a load:
Solution
Suspension
Bed Load

16. Stream Load
Solution
Material is carried in solution after it becomes dissolved in a stream’s water.

17. Stream Load Suspension
All particles small enough to be held up by the turbulence of a stream’s moving water are carried in suspension.
Silt, Clay, Sand

18. Stream Load
Bed Load
Large sediments that are too heavy to be held up by turbulent water.
Consists of sand, pebbles, and cobbles that the stream rolls and pushes along the bed of the stream.

19. Stream Load
Bed Load
As the particles move, they rub, scrape, and grind against one another or against solid rock of the streambed in a process called abrasion.
This causes the rocks to be polished and round.

21. Stream velocity and carrying capacity
The ability of a stream to transport material is called the carrying capacity.
Discharge = The measure of the volume of stream water that flows over a particular location within a given period of time.
Expressed in cubic meters per second (m3/s)

22. Stream Velocity & Carrying Capacity
Discharge = width x depth x velocity (m) (m) (m/s)
As discharge increases so does carrying capacity

23. Floodplains
Floods occur when water spills over the sides of a stream’s banks onto the adjacent land.
Floodplain: broad flat area of land that extends out from streams for excess flooding

25. Floods
Flood stage = level where a stream overflows its banks and the crest of the stream is at max height
Upstream flood = the flooding of a small area. They are localized and cause damage within a short period of time.

27. Downstream floods
Heavy accumulation of excess water from large regional drainage systems.
Causes extensive damage.

29. Flood monitoring and Warnings