1. Chapter 6.1
Running Water

2. Water is very important on Earth – 97. 2% is in oceans, 2
Water is very important on Earth – 97.2% is in oceans, 2.15% in ice sheets and glaciers, and 0.65% in lakes, streams, groundwater, and the atmosphere.
Water moves through the oceans, atmosphere, solid Earth, and the biosphere. This is called the water cycle.
The Water Cycle

3. 1. Water evaporates into the atmosphere from the ocean.
2. Winds move the moisture-rich air until the moisture condenses into clouds.
3. Precipitation – rain, snow, sleet, and hail – then falls to Earth.
4. Water that falls on land must make it back to the ocean to start the cycle over again.
The Water Cycle

4. When precipitation falls on land some of that soaks into the ground through infiltration – this is the movement of surface water into rock or soil through cracks and pores.
This water eventually ends of in lakes, streams, or oceans.
When the Earth cannot soak up the water it flows over the surface to lakes and streams as runoff.
Plants also release water into the atmosphere by transpiration.
In very cold areas water may becomes part of a glacier. Glaciers store large amounts of water on land.
Precipitation on Land

5. For the water cycle to be in balance, the average precipitation must equal the amount of evaporation.
In small areas this may not be the case, like there is more evaporation than precipitation in the ocean, but the level of the oceans aren’t changing so that indicates a balance.
Earth’s Water Balance

6. Gravity is a big factor in the way that water makes it to the ocean
Gravity is a big factor in the way that water makes it to the ocean. Streams and rivers carry it downhill from land to sea.
Velocity, the distance that water travels in a period of time, differs for different streams and rivers.
Fastest moving water is along straight stretches in the center of the channel, just below the surface.
The velocity also determines the rate of erosion and transportation of materials by a stream.
Factors that affect a streams velocity are: the shape, size, and roughness of the channel, and its discharge.
Streamflow

7. Gradient Gradient is the slope or steepness of a stream channel.
Gradient is the vertical drop of a stream over a certain distance.
The steeper the gradient the more energy the stream has as it flows downhill.
Gradient

8. Channel Characteristics
A stream channel is the course the water in a stream follows.
Water will experience friction from the sides and bottom of its channel.
Friction slows its forward movement.
Smooth channels and large channels have faster moving waters.
Channel Characteristics

9. The discharge of a stream is the volume of water flowing past a certain point in a given unit of time, measured in cubic meters per second.
Discharge

10. Changes from Upstream to Downstream
A profile of a stream is the cross-sectional view of a stream from its source (headwaters) to its mouth (where it empties into another body of water).
Gradient decreases between a stream’s headwaters and mouth, discharge increases. This is because more tributaries enter the main channel as it moves downstream.
Tributary is a stream that empties into another stream.
Changes from Upstream to Downstream

11. Base level is the lowest point to which a stream can erode its channel.
This is the level where the mouth of the stream enters the ocean, a lake, or another stream.
2 types of base level – ultimate base level (sea level) and temporary base level (lakes, streams)
A stream is a broad, flat bottomed valley that tis near its base level and has many bends (called meanders).
Base Level