Chapter 9 - Water
Water Cycle
Water Budget
The World’s Water
• Oceans, lakes, rivers,
groundwater, atmosphere, living
things, glaciers, and more…
• Water is measured by volume.
“How much space it takes up.”
• 97 % is in the oceans
The World’s Water
• Less than 3% is fresh!!!
–2/3 is frozen in ice caps
–Rest is fresh (usable) water
–Works out to be less than
1/2 of 1%
OCEANS 97.2%
ICE CAPS 2%
GROUNDWATER 0.78%
LAKES 0.013%
SOIL 0.006%
ATMOSPHERE 0.0007%
RUNNING 0.0002%
BIOSPHERE 0.0001%
Where is the fresh water?
• Tiny part is flowing on the
surface of Earth (rivers,
streams)
• 100 times that is stored in lakes,
swamps, etc.
• 50 times that is stored in the
ground as groundwater.
Water Cycle
• Again like all matter, water is
recycled.
• Simple water cycle (Magnificent
7):
Evaporation-liquid to gas
Transpiration-liquid to gas in
plants
Water Cycle
Condensation–Gas to liquidclouds
Precipitation-gas to
liquid/solid
Runoff-running water on
surface
Groundwater-soil moisture,
Water Budget
•Compares the input
(water you get) and
output (water you use) of
water in a specific region.
Water Budget
• Controlled by many different
climate factors
–Air temperature
–Humidity
(Season
Extremes)
–Rainfall amount
–Soil Type
Water Budget Graphs
• A comparison between
Moisture supply (precip) and
Moisture demand (evap)
• A water budget has 4 parts:
usage, recharge, surplus,
and deficit
Water Budget Graphs
• Usage – When plants,
humans, sun is taking water
out of the system.
• Recharge - When the ground
water is being filled back up
Water Budget Graphs
• Surplus - Rainfall is greater than
the need. Soil is moist.
• Deficit - Need for moisture is
greater than the rainfall coming
into the system. Soil is dry
Rocks Holding Water??
Porosity – Volume of space in
between rocks/soil that can hold
water
Permeability – The rate at which
water can pass through the pore
spaces of rock/soil
Rocks Holding Water??
Rocks Holding Water??
• Impermeable – Water cannot
pass through the pore space.
• Capillary – Ability of water to
“stick” to its surroundings by its
surface tension
Rocks Holding Water??
Water Table
Water Table
• Ground becomes saturated with
water. This is the ground water
that we have been talking about.
• Water Table – The top portion of
the “zone of groundwater
saturation”
Water Table
• Zone of Aeration – Water and
air mixed with the rocks and soil
• Capillary fringe – Border
between air/water and just
water. Right above the water
table (pg. 154)
• Zone of Saturation – Just water
in the soil and no air
Wells and Springs
• Ordinary well - A hole dug or
drilled down below the water table.
( water must be pumped out)
• Spring - Place where the water
table is at the surface.
• Artesian well - A well that is
pressurized. (water will not have to
be pumped out)
Aquifers
• Are permeable materials that
contain and carry groundwater
–Best are - Sand, gravel, and porous
sandstone
Link to Page About Water
Resources