Download Water Underground - Northwest ISD Moodle

Write all the information on all the slides. If there is a
picture on the slide, it must be drawn as well.
You may choose the format for your notes:
• regular
• c-note style.
Groundwater
Where does it come from?
 It comes from precipitation that
soaks into the ground!
 There are spaces between the soil
or rock particles and the water
trickles through these spaces.
Porosity & Permeability
Porosity: the space between rock in a given
volume of soil; it is usually expressed as a
percentage (pore space)
“The soil has a porosity of 26%”. This means if
you have 100 mL of soil, 26 mL will be “open”
pore space.
Permeability: how easily water flows through a
soil; usually given as a rate (mL/sec or mL/min)
Material that water cannot pass through is called
IMPERMEABLE. Clay and granite are examples
of impermeable materials.
Porosity
Permeability
Increasingly impermeable
Water Zones
 Once water reaches an impermeable layer, water
is trapped and water begins to fill up the spaces
above the impermeable layer. The area that
becomes totally filled with water is called the
SATURATED ZONE.
 The top of the saturated zone is called the
WATER TABLE.
Bringing Up Groundwater
 Springs: where the water table meets the
surface of the ground
Aquifers
 Aquifer: Any layer of soil/rock that holds
water. They can small or as large as several
states! There are confined and unconfined
aquifers.
Ogallala Aquifer
Wells
 Wells – holes that are drilled to reach the
aquifer; must be drilled below the water table!
 The bottom of the well should be in the
saturated zone.
Artesian Wells
 Water rises in this type of well because there is
pressure within the aquifer. Water is trapped
between impermeable layers and when it is
punctured the pressure sends water upward!
Watershed
 An area of land
where the surface
water and
groundwater drains
into a particular
body of water
separated from
each other by
drainage divides