1. Unit 3
The Hydrosphere

2. Where does our water come from??
71% of the Earth’s surface is covered with water
97% of water is in the oceans
3% is freshwater
2 % is in glaciers and ice
0.4% is in rivers, streams, lakes, and the atmosphere
0.6% is in groundwater (and available for human consumption)

4. Hydrologic Cycle Evaporation Liquid changing to a gas (vapor)
Water at the surface of lakes, rivers, oceans, etc. evaporates due to energy from the sun.

5. Hydrologic Cycle Transpiration Water evaporating from plants.
Plants lose water through their leaves, stems, and roots.

6. Hydrologic Cycle Condensation
When water vapor changes into a liquid form.
Water vapor rises in the air and cools and small water droplets are formed – this creates clouds.

7. Hydrologic Cycle Precipitation
When water is released from a cloud in the form of rain, snow, sleet, freezing rain, etc.
Precipitation is the primary way water enters the atmosphere.

8. Hydrologic Cycle Infiltration
The process by which water gets absorbed into the ground

9. Hydrologic Cycle Runoff
Water that doesn’t get absorbed by the ground or evaporated becomes runoff.

10. Do bed load worksheet

11. Watersheds
Land area that contributes to a stream, lake, or other body of water
Imaginary Line called a divide separates a drainage basin
Divides usually along ridges

13. River Basins
River basin – portion of land drained by a river and its tributaries
Tributary – a river/stream flowing into a larger river or lake

14. What is the difference between a river basin and a watershed?
Both river basins and watersheds are areas of land that drain to a particular body of water (lake, stream, river, estuary)
River basins … all water drains to a large river
Watershed … a smaller area of land that drains to a smaller stream, lake, or wetland
There are many smaller watersheds within a river basin.

15. Groundwater
Groundwater is where our potable water (safe for human consumption) comes from.

16. Groundwater The importance of groundwater Consumption
Recharge/discharge of lakes and rivers
Pollution/Contaminates
Slope Stability and Subsidence

17. Porosity
Porosity is the amount of pore space in a rock, or the open spaces between the grains.
a. High porosity – beach sand
b. Low porosity – well-cemented sandstone

18. Permeability
Permeability is the ease with which the fluids flow through a rock or sediment.

19. Porosity and Permeability
Permeability depends on:
Porosity – the higher the porosity the higher the permeability.
Larger Sediments are more permeable than finer grained sediments because the pores between the grains are larger.
Sorting or arranging of pores.
Connectivity of grains.
Packing. (Controls pore size)

20. The Water Table
Infiltration – when it rains, some of the water percolates, or soaks, into the ground.
Some of the water is held in the soil because it clings to the soil particles
Some may evaporate from the soil
Zone of aeration – may be used by plants

21. Water Table
Excess water penetrates downward until it reaches the water table.
zone of saturation – below the water table, all of the pore spaces are filled with water.
The water table is the top of the zone of saturation.

23. Water Table
The water table is not flat. It mimics the topography. It stands somewhat higher under hills, and lower under valleys.

24. Water Table
Springs, lakes, swamps, or rivers are present where the water table intersects (or lies above) the ground surface
If a well is drilled, the water level in the well is at the water table.

25. Water Table
Think about when you went to the seashore and dug a hole in the sand near the sea. What happened?

26. Aquifers
An aquifer is a water-bearing rock.
Aquifers have high porosity and high permeability.

28. Wells
How much water can a well yield?
An average figure is about 5 gallons per minute.

29. Artesian Well
A deep well that passes through impermeable rock and reaches water that is held under pressure between the impermeable rock layers