1. Water Above and Below Ground
Sources and Significance

2. Water Above Ground Lakes, ponds and wetlands Streams and rivers
Ground water
Glaciers
Drainage basins

3. Water Distribution

4. Only 3% of the Earth’s water is fresh water (no salt).
2/3 of this water is frozen in ice sheets.
Therefore only 1% of the fresh water on Earth is available.

5. Ground water...
Precipitation that falls on land and sinks out of sight.
Sinks through pores in rocks until it reaches bedrock where it pools.
Drilling to these pools make wells.

6. Groundwater Systems

7. Review of Groundwater Systems
Underground water:
Most of Earth’s fresh water that is not locked up in glaciers or trapped as vapour in the atmosphere can be found underneath the ground
There is more fresh water underground that there is in all the lakes and rivers combined
Underground water flows through a series of canals or streams and only comes to the surface as springs
Humans have tapped into underground water supplies for thousands of years by digging wells

8. Zone of saturation:
Beneath the surface of the ground, the soil contains a permeable layer with numerous pores
When water is absorbed into the ground, it fills these pores much the same way a sponge is filled
This layer of porous soil is referred to as the zone of saturation when all the pores are filled

9. Water table: The top of the zone of saturation
The depth changes depending on how full the zone of saturation is
When humans dig wells, they tap into the zone of saturation
If the zone dries up, the water table lowers and may become lower than the bottom of the well

10. Aquifer:
Water moves through the zone of saturation through a series of channels or canals, continuing toward the lowest point
These channels and canals are known as aquifers

11. Wells and Springs:
Water in aquifers is brought to the surface through springs or wells
Wells are made by drilling a hole through the soil and rock to a point below the water table. Water is then pumped up to the surface
Springs are made when groundwater flows naturally out onto the surface. This usually happens on hillsides or gullies where the water table is exposed by a dip in the land
Hot springs are groundwater that has been heated by rocks that come in contact with molten material under Earth’s surface