Habitats: Can We Keep the Lake Clean?
Connections to the curriculum:
Geography, earth science, environmental studies
Connections to the Canadian National Standards for Geography:
Environment and Society
One to two hours
• Blackboard or whiteboard
• Colored chalk (or erasable markers if you are using a whiteboard)
• Blank white paper
• Drawing materials
• Rulers (optional)
Suggested Grade Level: K - 3
This lesson introduces students to the water cycle by having them help draw a picture of a lake ecosystem,
adding human impacts that affect water quality. Students will help fill in the components of a drawing of a water system.
They will conclude by creating their own illustrations of human-induced changes to the freshwater habitat of a lake ecosystem.
- help draw a picture of a lake ecosystem;
- discuss the water cycle and the reasons why lakes
- describe how humans can impact the water cycle; and
- draw pictures illustrating a scenario involving human-induced
changes to a lake ecosystem.
- Acquiring Geographic Information
- Organizing Geographic Information
- Analyzing Geographic Information
On the board, draw a picture of a lake with a river
flowing into it. Draw some mountains in the distance
where the river originates. Have students take turns
adding the following features to the drawing: trees,
fish, animals, houses, farms, and people doing activities
related to the things they have drawn (e.g., fishing
Ask students to look at the picture and think about
why the river and lake water is important to everything
else pictured. What do the plants, animals, and people
in the picture use the water for? Why is it important
that this water be kept clean and plentiful?
Tell students that the water in the river and lake initially
comes from the sky in the form of rain or snow. When
it rains in the mountains or anywhere upstream, the water
flows downhill through the river channel and eventually
into the lake. Similarly, when snow melts in the mountains,
it turns liquid and flows down the river into the lake.
Have they ever seen evidence of these phenomena in their
Introduce students to the process of evaporation by
explaining that, as water travels down the river and
into the lake, it slowly evaporates and returns to the
air. The river and lake will not become empty, however,
because rainwater and snowmelt will replenish them.
Canadian Geographic For Kids!
Geographic: Geography Action—Habitats
Geographic: Geography Action—Rivers 2001
Learning: The Water Cycle
Environmental Protection Agency: The Water Cycle at
Ask students to imagine that some of the people in the
drawing have decided to increase their farmland and build
new houses and other buildings. Add these changes to
the illustration on the board. Ask students to describe
the reasons why these activities will require additional
water, and ask them to explain where the water will originate
from (rain or snowmelt). How will the people get the
extra water for their farms or houses?
Draw an irrigation channel with water pipes that extend
to the farms and homes. Ask students to explain what
might happen to the river and the lake if these irrigation
channels are built. They should state that, eventually,
the water levels will decrease as more water goes to
the farms and homes.
Add to the illustration some runoff from the farm and
homes. Will this water be clean? Explain to students
that this water is likely to contain such substances
as soap, farm fertilizing chemicals, and even car oil
or gasoline. These chemicals are not healthy for the
fish and plants that live in the water. You or your students
can draw this water as brown or gray to depict water
that is not clean.
Ask students to look at the illustration and think about
what they have seen. Discuss the changes that have been
made to the drawing.
Suggested Student Assessment
Give each student a large piece of white construction
paper and help them divide the page into six equal sections
using a pencil and ruler. Or, give students two pieces
of white letter-size paper and help them make a six-page
As you read each of the following scenarios, have students
draw pictures illustrating what you have stated in each
of the six sections of their paper or booklets. As they
draw successive pictures, they should modify the size
and appearance of the water and the number of fish in
the lake to reflect the changes that are occurring.
Seven fish swim happily in a clean lake.
A person decides to clear land and develop a farm near
A person decides to build a house by the lake.
Three more people decide to build houses by the lake.
Extending the Lesson
Have students plan and perform short skits depicting
the water cycle. They can take on the roles of raindrops,
clouds, the sun, soil, and other physical features involved
in the water cycle.
Habitats: Can We Keep the Lake Clean? (Adobe PDF document)