portions of the lesson from “What goes on Down
Under”, a lesson available in The Water Sourcebook;
more information available at http://www.wef.org
Modified by Rachel Hughes and Karen Munroe for the PULSE
||4 - 5
of various sizes
Plastic shoe containers
Soap dispenser pumps
Lemon powder or citric acid
2 small buckets per group
2 500ml paper cups or small watering cans per group
In the previous lesson students explored
watersheds as they tracked where their water came from.
In this lesson students further explore groundwater
systems specifically and explain how ground water moves
through a watershed and how it can become contaminated.
Students build groundwater models and then explain
a mystery contamination determining point source and
non-point source contamination.
1. evaluate the effects of point and non-point sources
of water pollution using a model
2. assess human impact on water quality
3. build a model which represents an aspect of the hydrosphere
and compare their model with the environment that they
Science Education Standards
Content Area D: Earth and Space Science
Most of us rely upon drinking water that comes from
two major sources: groundwater and surface water.
Groundwater is thought to make up the majority of
the fresh water that is potable and is an important
source of water for much of the U.S. population.
Groundwater is any subsurface water that occurs beneath
the water table in soil. Surface water is water that “occurs
in lakes, rivers, streams, or other fresh water sources
used for drinking water supplies.” While most
drinking water in the United States is withdrawn
from groundwater sources, surface water remains a
significant water resource.
Each water source has a unique set of contaminants;
groundwater stores pesticide chemicals and nitrate
while surface water contains most bacteria and other
microorganisms. Because of the interconnectedness
of groundwater and surface water, these contaminants
may be shared between the two sources. Neither water
source can ever be entirely free from water contaminants.
Due to the cycle of water (hydrology), the two sources
of drinking water feed each other, sharing contaminants.
Groundwater is generally stored in aqueducts, underground
layers of porous rocks that are saturated with water.
These aqueducts receive water as soil becomes saturated
with precipitation or through stream and river runoff.
As the aqueducts exceed their capacity for water
storage, they will bleed water back into streams
or rivers. The aqueducts maintain a natural balance
of water, alternately receiving or giving water as
their saturation levels oscillate. Throughout this
process, water constantly moves between surface and
groundwater sources, sharing contaminants.
and Resource Websites
Groundwater Models - Arizona Department of Water Resources
Dependent on how much time the teacher wishes to spend
on creating the models, they may wish to assemble
some portions of the models before hand to shorten
class time. In addition, it may be necessary
to stagger the use of the models to allow for
Making the Groundwater models:
Groundwater models can be bought from scientific education
suppliers and some water utility company outreach departments
may have some available to borrow. However, buying multiple
models is often an expensive option beyond the reach
of the classroom; having students build models gives
an opportunity to really explore the nature of groundwater
and specifically reflect the groundwater system in their
- Previously students have explored watersheds in their local
area and dependent on the area they live in,
they may see active streams and rivers. Most
of them will
rely to a great degree on groundwater for their
drinking water. Reflect with students what they have learned
about watersheds. Does all the water that they
onto the watershed model flow along the surface?
They should have noticed that water does seep through the
landform model in addition to going over the surface.
Ask students where their drinking water comes
For much of the population it comes from groundwater.
Try to direct students to identify wells as a
source. In an area like Arizona the lack of large water
aids in targeting groundwater and wells as a source
of water. Ask where the water that feeds the well
comes from. Identify that water percolates through
and rock. If students use terms like groundwater,
water table and saturation write these on the
that in the next few days the students will be building
models to explain how much
of the water
that they drink comes from subsurface sources
and why protection of those sources is important.
- Ask students to reflect back, again, to their watershed
landform models from previous lessons.
water flowed through as well as on top of
the landform. In
the real world what factors would affect how
much water flowed on top or became part of
the soil and
Direct students to think about areas near
their home or school; what happens to water that
bare ground, vegetation, sloped, or flat surfaces?
Once students have addressed surface cover,
push them to
identify soil texture, porosity, rock formations,
etc. Explain that they will be building a
model cross section
of an area of land. They will have to include
different materials to reflect the different
make up the subsurface landscape.
- Explain what groundwater is, not underground lakes and
rivers, but water held in between
cracks and holes
in the rock. Aquifers are rock units that
have lots of open spaces, and are very porous,
to flow through them. There may be multiple
aquifers that are not connected within the
same area. Ask students
how that might occur. Ask a volunteer to
draw a cross section that would show how multiple
occur in the same piece of land, but not
- Explain that even where there are lots of open water sources,
people often choose
water source. Ask students to suggest
reasons why. This can be something that they research
Students should also try to find out how
much their water supply is reliant on
What is positive
about this? What might be problematic?
- Students should construct a model of an aquifer.
a. Using gravel of various sizes students
should construct subsoil aquifers
in a plastic container
(a see through
shoe box would be appropriate). They
should try to create, not a flat surface,
something with a few
structures and a valley area in the
middle. This will represent a river.
gravel with sod except
in the valley where the river will
flow. Once they are sure where they want the
go and have
you their model, they should pierce
the plastic box at the beginning and
above the valley floor and just below
the top of the box. These are overflow
the flood waters if too much water
gets into the box. Each group should have
to handle overflow.
b. Students should pierce the base
of 2, 500ml, cups with tiny holes.
be used to
into the system. Small watering cans
might also be useful.
c. Using the pierced paper
cups students ‘rain’ a
measured amount of water
onto their landscape.
They should note how the
water infiltrates the
become ground water. Students
should note what happens
to the water falling on
d. After pouring one cup of water
onto the system, the students should
a wax pencil
the water level
around the container. This is the
water table. Ask students what occurs
the water table
the base of
the valley. They should see a river
or pond. How does that relate to the
in? In an arid area
like Arizona, do they ever see evidence
of the water table rising?
e. Students should insert a pump into
one of the hills down toward the groundwater.
the water into a paper cup (without
holes). What happens to the water
to the pond or river?
f. After modeling the water table,
students should reconstruct it using
of soil and gravel
samples from their
environment. They should describe
the layers within their landscape
as to what will
happen. How does this compare to the
original model? How would they explain
would they test their
g. Discuss point and non-point
pollution with students.
What do they think
those terms mean?
think of examples of point
and non-point pollution?
As a class
make a list of these examples.
Explain to students that
they are going to
point or non-point
source in their aquifer.
Ask them as a class what
types of pollution
of the well, contamination
within the rocks, etc.
They are to reconstruct
and using citric acid
powder as the
contaminant, place it
somewhere within the system
it will get into
the water supply. They
should mark down where
they placed it and then
pH paper to test the water,
should come up with a
plan to assess the watershed
to determine where the
and whether it is point
or non-point. Students
write a report
where they think the contamination
is within the watershed
responses to where the water table is along with responses
as to what happens to the water table when it is pumped
allows for assessment of basic understanding about
the aquifer. Descriptions of their local material groundwater
system and their predictions as to how it will respond
to different water levels may used to assess their
understanding of material differences within the watershed.
The final report provides an opportunity for assessment
of their ability to design a test, use data to draw
conclusions and the ability to correctly use conceptual
terms about groundwater.