Do you get the
groundwater picture yet?
What is an “aquifer”?
An underground formation that is
capable of storing AND
transmitting water
Some aquifers cover 100’s of
square miles and be 100’s of
square feet thick. Others may
only cover a few square miles and
be a few feet thick.
Water quality and water quantity
vary from aquifer to aquifer, even
vary sometimes within the same
aquifer! (how can this happen?)
Some aquifers yield millions of
gallons of water per day and
maintain their water levels, while
others may only be able to
produce small amounts of water
each day.
The rate of movement of ground
water varies based on the rock
material in the formation through
which the water is moving. After
water percolates down to the
water table, it becomes ground
water & starts to move slowly
down gradient.
Water movement responds to
differences in energy levels. The
energies that cause ground water
to flow are expressed as
gravitational energy & pressure
energy (both are forms of
mechanical energy).
Gravitational energy comes from
the difference in elevation
between the recharge area (where
water enters the ground water
system) and discharge area
(where water leaves the system).
Pressure energy (hydraulic head)
comes from the weight of
overlying water and earth
materials.
Drilling wells is the best way to
get the ground water picture!
You have a well log for 25
different wells.
You are to illustrate your well
data on a strip of paper.
USE PENCIL FOR THIS
Mark off 1” sections on your strip
of paper.
Using your well data, draw the
boundary lines for each substrate.
Fill in the substrate sections with
the appropriate markings.
We must all use the same colors:
black line for the water table
yellow – fine sand
orange- medium sand
red – coarse sand
green – sandstone
clay- brown
dark blue – gravel
purple - granite
If the horizontal scale of the cross section is 1 inch
= 1 mile, and the vertical scale is 1 inch = 50
feet
How many miles are horizontally represented in
the cross section?

25 miles

How many feet are vertically represented in the
cross section?

600 feet


How many feet below the surface is the water
table?
(yes, I know it varies, but from what depth to
what depth??????????????)

12.5 to 250 feet

Imagine a drop of water falling on the surface
near well #8. What type of pollutants might
enter the groundwater there?

Fertilizers, pesticides, tractor fuel and POO
POO!!!!!!!!
Through which layer(s) would a drop of water
move the fastest?

GRAVEL

Which layer would take the longest for a drop of
water to get through?

CLAY
Got a calculator? Get it out. If the groundwater
has a flow rate of 100 feet per day, how long
would it take the water in the sandstone
formation to move from well #1 to well #15?

792 days or a bit over 2 years

How deep is the zone of aeration at well #11?

150 feet

How deep is the zone of saturation at well #6?

About 325 feet

Last question: Where would you label a “cone of
depression” on the class chart?

Between well #11 and well #19

Are you “water-logged” yet???
 Get it? Ha, Ha, Ha