1. Running Water and Ground Water
Chapter 6
Running Water and Ground Water

2. 6.1 Running Water
The unending circulation of Earth’s water supply is the water cycle
Water changes states (solid, liquid, gas) readily at temperatures and pressure common on Earth
The cycle is powered by the sun
Water evaporates to the atmosphere, it is transported by winds, condenses into precipitation (falling to Earth)

3. 6.1 Running Water
Infiltration is the movement of surface water into rock or soil through cracks and pore spaces
Seeps into lakes, streams, or oceans
If it isn’t absorbed into the ground, it creates runoff
Plants absorb water and it returns to the atmosphere by transpiration

4. Water Cycle

5. 6.1 Running Water
Balance in the water cycle means that the average annual precipitation over Earth is equal to the amount that evaporates
Local imbalances exist
If the overall cycle wasn’t balanced, we would notice a drastic change in the oceans’ level

6. 6.1 Running Water Streams/rivers flow downhill due to gravity
The ability of streams to erode and transport material depends on its velocity
A steeper gradient (steepness) provides more energy to the stream as it flows downhill
The shape, size, and roughness of the stream channel (course it follows) affect the friction, which slows the water
Discharge is the volume of water passing a point in the stream (affect size and velocity of the stream)

7. 6.1 Running Water
The gradient decreases between a stream’s headwaters and mouth, while the discharge increases
More tributaries (stream that empties into another stream) enter the main channel
Typically a mountain stream has a lower velocity than at the mouth of a river
Friction affects mountain streams more (boulders and smaller channel)
Channel usually smoother downstream

8. Stream Profile

9. 6.1 Running Water
The base level is the lowest point to which a stream can erode its channel
It is the level at which the mouth of the stream enters the ocean
Sea level is the ultimate base level
Temporary base levels include lakes, resistant layers or rock, and main streams
A stream in a broad, flat-bottomed valley near its base level meanders (has many bends)

10. Meander

11. Incised Meander