1. 2.3.2a Water Cycle, Surface Water, and Ground Water1

2. Water Cycle Water is EVERYWHERE About 97.2 % is in the oceans
About 2.15 % is in glaciers and ice sheets
About 0.65 % is freshwater in lakes, streams, groundwater, and the atmosphere
Water constantly moves among the oceans, the atmosphere, the solid Earth, and the biosphere. This unending circulation of Earth’s water supply is the water cycle. 2

3. Water Cycle

4. How much of our planets water is fresh?
Water Cycle
How much of our planets water is fresh?
How does that affect life on our planet? 4

5. Processes involved in the Water Cycle
Not in notes, just know
REALIZE: Running water starts as precipitation and either infiltrates the surface to flow under ground, or becomes runoff and creates streams and rivers

6. Water Beneath the Surface Distribution and Movement of Water Underground

7. Groundwater
Much of the water in soil seeps downward until it reaches the zone of saturation.
The zone of saturation is the area where water fills all of the open spaces in sediment and rock.
Groundwater is the water within this zone.
The water table is the upper level of the saturation zone of groundwater.

8. Groundwater
Movement
Groundwater moves by twisting and turning through interconnected small openings.
The groundwater moves more slowly when the pore spaces are smaller.
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9. Groundwater
The movement of water through the ground depends on 2 factors
Porosity:
The percentage of pore spaces
Determines how much water can be stored
Permeability:
The ability to transmit water through interconnected pore spaces

10. Groundwater Impermeable rock Groundwater Surfacewater Recharge Aquifer
Precipitation
Evaporation
Stream
Water table
Groundwater

11. Groundwater
Wells that are drilled into the zone of saturation are successful
Wells drilled into the zone of aeration (aka not deep enough) are not successful
Over-pumping a well can create a cone of depression

12. Groundwater

13. Aquifers
An aquifer is underground soil and/or rock through which water can easily move.
Groundwater is stored in aquifers

14. Aquifers Unconfined aquifer Confined aquifer
Has no barrier between its top layer and the surface of the ground
Water level rises and drops in response to precipitation infiltrating directly above
Confined aquifer
Sandwiched between two largely impenetrable layers (clay, shale, etc)
Recharges more slowly due to limited number of places through which rainfall can enter

15. Aquifers of NC

16. END OF PART I

17. Path of a drop of water…
Remember: A drop of water can either infiltrate into the ground (groundwater) or runoff the surface into a river or stream

18. Surface Water and Ground Water
Groundwater and surface water have a reciprocal relationship, regularly feeding each other. Most streams and rivers get about half their volume from groundwater.

19. Floods
During a flood, surplus surface water helps recharge groundwater.

20. Flood and Flood Control
A flood occurs when the discharge of a stream becomes so great that it exceeds the capacity of its channel and overflows its banks.

21. Flooding What are some things that cause flooding? Heavy Rain
Rapid Spring Snowmelt
Why are floods bad?

22. Flooding There are several methods used to help prevent flooding:
Artificial levees
Create Dams
Sandbags
Limit construction around areas known to flood
Mississippi Flooding
What caused the flood?
What caused the most damage during the Flood?

23. Drainage Basins
A drainage basin is the land area that contributes water to a stream.
A divide is an imaginary line that separates the drainage basins of one stream from another.

24. Drainage System Pattern formed by streams, rivers, and lakes
Depends on
Topography of the land (landforms)
Hard or soft rocks
Gradient of the land (how steep it is)
Divided from each other by topographic barriers (mountains/high points) called a watershed

25. Rivers Flow of a river or stream is due to GRAVITY.
Velocity of a river is due to the geology of the watershed
How steep, how narrow, much water, etc
Discharge (volume rate of water flow; or how much water is passing by) is measured by:
Width x Depth x Velocity