A watershed is defined as the land area that drains into a particular water body. During rainstorms, water flows over land as runoff and collects in streams, rivers, and other channels, with the entire land area draining into these waterways comprising the watershed. Watersheds resemble branching tree patterns as tributaries flow into streams and streams join together to form larger rivers. Pollutants from cities, factories, roads, and other sources are carried by runoff during rainstorms and drain into waterways, mixing together as they flow through the watershed from higher to lower elevations.

1. Watersheds

2. What is a watershed?
The land area that drains into a
particular water body. All land is in a
watershed and everybody lives in a
watershed.
During a rainstorm, the water that flows
over the land as runoff collects in channels
such as streams, canals, rivers, etc. The
land area that drains water is called a
watershed.

3. From an aerial view, drainage patterns in a
watershed resemble a network similar to the
branching pattern of a tree.
Tributaries, flow into streams.
Streams eventually empty into a
large rivers. Like other branching
patterns (e.g. road maps,
veins in a leaf, the human nervous
system), the drainage
pattern consists of smaller channels
merging into larger ones.

5. So why do we worry about water so much?

6. 1. Divide the paper into 4 parts. Each student will draw
a town in their quadrant. Connect the towns with
roads and railways.
Add one lake.
towns are
red/orange/pink
train tracks are
brown
roads are black
lake is blue

7. 2. Take the sheet of paper and crumple it.
3. Next, partially smooth it out. It should look like a
model of hills, some ridges and mountains. This
represents your watershed.
towns are
red/orange/pink
train tracks are
brown
roads are black

8. 4. Use the markers to color along the edge of the
creases. You may want to use different colors to
represent a variety of pollutants, such as fertilizer, oil,
pesticides, litter, etc.
5. Lay the paper out on the plastic and shape it so that
it looks like a watershed.
6. Use the creased lines
to show elevated land
areas.
Use the skittles to place factories
on your map. Place them near a
road or railroad.

9. 7. Write your hypothesis.
What do you think will happen in your watershed
when it begins to rain?
If it begins to rain in my watershed, then …..
Be specific!
8. Use the bottle of water and
gently spray the top of the
watershed. Keep spraying the
paper until the colors begin
to flow.

10. Pre-AP – Write at least 5-7 sentences in your paragraph.
Science I – Write at least 3-5 sentences in your paragraph.
9. Describe what happened at the lowest point of the
watershed.
Did your pollutants remain separated?
What happened near the towns, factories, roads, etc.
Did the different pollutants mix together?
If so, where did this happen in the watershed?
Where would you want to build a house in this watershed?
Where would you want it to be in relationship to your
factory and cities?

13. Areas of higher elevation called divides
separate watersheds from each other.
Water flows through a series of channels
and eventually it collects in a wide river
that empties into a body of water such as
an ocean or lake.
Water flows
from areas of
higher elevation
to lower elevatio

14. How do pollutants
enter the water supply?
Urban development removes
vegetation and replaces it with
buildings, streets, walkways, and
driveways, thus preventing water
from infiltrating the soil.