FRESHWATER
EARTH'S WATER
97% Saltwater---3% Freshwater
Oceans
Contain Salt Water
Pacific, Atlantic, Indian, Arctic
Ice
Sheets of freshwater
Cover Antarctica, Greenland
They break and melt as they reach warmer water
Most of the freshwater is found here
Rivers & Lakes
Sources of freshwater for humans
Contain very little of the earth's freshwater
Groundwater
Fills cracks and sapces in soil
More freshwater here than in rivers and lakes
Water Cycle
Continuous process where water moves from the earth's surface to the atmosphereand back
3 Continuous Steps
Evaporation
Liquid water heats up and changes to gas (Water Vapor)
Plants release water into the air through their leaves (Transpiration)
Condensation
Warm air carries the water vapor up where it cools
Drops of water clump together to form clouds
Precipitation
Water droplets grow larger
Cloud can't hold large drops so it falls to the ground
Surface Water
Rivers
Snow Melts in the mountains, water drains off....rivers form
Tributaries: Smaller rrs and streams that feed the main river
Remember---a river system is the river and it's tributaries
Watersheds
Areas that providewater for the river...
also known as Drainage Basins
Divides
Ridges of land that separate watersheds
Continental Divide:
The longest in N. America--Follows the Rocky Mountains
Ponds
Small, Shallow areas of standing Water...
Form when water collects in depressions or low areas
LAKES
Deeper/Bigger than ponds---Sunlight doesn't reach the bottom
Reservoirs--Lakes that hold human water supplies
Wetlands
Areas that stay wet most of the year
3 types
1. Marshes: Grassy, covered by shallow water
2. Swamps: Flooded Forest with trees & Shrubs, mostly in warm, humid climates
3. Bogs: Cooler areas left from melting ice sheets....lots of moss here
Water Underground
Comes from Precipitation---soaks into the ground with gravity---fills up spaces between particles &
cracks.
Permeable vs. Impermeable
Permeable---large pores allow water to pass through
Impemeable: Don't allow water through
How does this relate to groundwater???
Saturated vs. Unsaturated
Saturated Zone: Totally filled (saturated) with water...
Top: Water Table
Unsaturated zone: Area above the water table where more water can be absorbed
Groundwater to Surface
Springs: groundwater flows from bubbles and cracks deep in the land
Aquifers: Underground layers of rock that hold water
Wells: Areas where aquifer has been drilled to bring water to the surface.
Pumps
Used to bring groundwater up---easier than a crank and bucket
Pumping water too fast can cause the well to dry up...
If pump goes out, you have to use other means to get the water to the surface
Wells
Artesian Wells: Pressure in the aquifer causes water to rise on it's own with no pump
Regular Wells: Require outside force to bring up water...
Springs & Geysers
Springs flow easily from cracks in the surface
Geysers: Hot sprinere water "erupts" from the surface from the pressure in the hot water...
Ice