1. Surface Water Movement

2. Hydrologic Cycle
Earth’s water supply is recycled in a continuous process

3. Hydrologic Cycle
Evaporation-Movement of water from Earth’s surface to atmosphere
Condensation- Movement from water vapor to clouds
Precipitation- water falls back on Earth
Infiltration- Water soaking into the Earth
Runoff- water on earth’s surface that flows downslope into lakes, streams, rivers, oceans, or puddles
Transpiration- water vapor from plants; Similar to evaporation

4. Runoff
A number of conditions determine whether water on Earth’s surface will infiltrate the ground or become runoff.
Vegetation
causes the soil to hold more water
water flows slower down plants allowing the ground to soak in more
Rate of Precipitation-
More water enters ground if rainfall is gentle
During heavy downpours , the rate of precipitation may exceed the rate of infiltration

5. Runoff Soil Composition: Determines how much water soil can hold
Slope: the steeper the slope, the less water is allowed to soak into the ground

6. Stream Systems Stream System- Large river and all of its tributaries
Water flows downslope to lower elevations
Can flow into lakes, oceans and other streams

7. Stream Systems Tributaries Rivers that flow into other streams
Example: Missouri river is a tributary for the Mississippi

8. Stream Systems Watersheds
All of the land whose water drains into a stream
Divide
A high land that separates one watershed from another

9. Stream Systems Stream Load: the material that a stream carries.
Stream load is carried in 3 ways:
solution: material dissolved in water
2. suspension: particles small enough to be held up by the turbulence of moving water (silt, sand, clay)
3. bed load: sand pebbles and cobbles that are rolled and pushed along the stream bed by water

10. Stream Velocity and Carrying Power
Carrying power: streams ability to transport material; this is dependent on stream velocity and volume
Stream velocity: effected by slope, depth, width of the stream
Discharge: width x depth x velocity
When discharge increases, carrying power increases
Increases during heavy rain, rapid snowmelt, and flooding

11. Floodplains
Flood- water spills over the sides of stream banks and onto adjacent lands
Floodplain- the area of land covered with stream water during times of floods
When water recedes off the floodplain, sediments are deposited on the land making the soil very fertile

12. Floods
Upstream flood: the flooding of a small area (localized) caused by a sudden rainstorm dropping large amounts of time (flashflood); short-term events.

13. Floods
Downstream flood: heavy accumulation of excess water due to prolonged rain or extensive snowmelt; longer lasting.

14. Streams, Wetlands, and Lakes

15. Stream Development Stream formation relies on adequate water supply
As a stream develops it changes width and size, and shapes the land over which it flows

16. Formation of Stream Valleys
Driving force of a stream- gravity
Stream actively erodes a path through the sediment or rock, a V-shaped channel develops

17. Meander
As stream channels develop into broader valleys , the volume of water and sediment that they can carry increases.
Sometimes the water begins to erode the sides of the channel in such a way that the overall path starts to bend and wind.
A bend or curve is called a meander.

18. Meander

19. Origins of Lakes Lakes can form from many different sources
Stream flows become blocked
Glacial origins (melted glaciers)
Dissolving of limestone cavern
Water from precipitation , runoff, and underground sources can maintain a lake’s water supply

20. A stream meander that no longer has access to water and eventually dries up.
Oxbow Lake

21. Lakes Undergo Change
Eutrophication: when a watershed enriches bodies of water with nutrients that stimulate excessive plant growth
Can be positive or negative

22. Wetlands
Wetland: low lying area that is periodically saturated with water and support a specific plant species
Areas include bogs, marshes, or swamps