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Water
as a natural resource
A study of watersheds can be introduced by
analyzing the importance of water as a natural resource. Discuss the hydrological cycle (water cycle)
and pose the question: “Do we ever get
new water?” Your students may be
surprised to learn that the answer to that question is no! Our water is in a continuous cycle, and
though it may take a variety of forms, it is the same water used over and over.
Water is used by plants and animals, evaporates, condenses and falls as precipitation. This cycle has been happening for billions of
years.
Students can undertake an analysis of
water use, either individually or as a class.
Keep water journals and document every time students use water. Calculate estimations of water used in daily
activities (an average flush of a toilet uses 5 gallons of water). Students can brainstorm ways to conserve
water and implement a class “water watcher” conservation activity. Perhaps students can teach family members or
other classes about methods to conserve water.
Identifying
watershed components
If possible, go outside to identify key
features around the school that contribute to the watershed. Examples might include smaller tributaries or
changes in the shape of the land. As you
identify these features students can describe or sketch them. This information can also be presented with a
photocopied map of the watershed that students use to identify and map critical
areas and land uses. Students can work
in a group to identify water features and use a blue marker to highlight each
of the features. In addition to water
features, groups can look for land uses near the river, such as farms,
wastewater treatment facilities and sources of erosion. You might choose to focus on the entire
watershed or perhaps a smaller area that is relevant to your school. Groups of students can also develop a key for
their maps.
Students can demonstrate their
understanding of some of the concepts presented herein by “becoming” drops of
water. Students can personify the study
of water by writing descriptions of the experiences of a water drop. Students can choose the specific location of
the drop and describe a sample day in the life of the water drop: What
conditions do they come across? Do they
ever change form?
Make
a model surface watershed
There are several different variations of
models that can be used to observe how surface waters interact in a
watershed. One of the more basic models
is to use a plastic box (like a dishpan or a sweater box) as the boundary. Your
students can create “mountains” and other landforms in this box. These landforms will be covered, so
miscellaneous items of varying heights can be used. Depending on the level of your class, you may
also simply choose to use crumpled paper to represent hills and mountains.
Once landforms are in place, cover them
with something water repellant, such as butcher paper or a plastic bag, and
tuck the edges into the bin. Where do
students think water will collect?
Why? You may see students
attempting to create waterfalls or lakes in their landforms. You can extend this activity and have
students use something to represent a house and decide on a location so that it
will be on dry land when it “rains”.
When they have predicted what will happen, provide spray bottles so
groups can create a gentle rain on land.
Where does the water go? What
happens when it rains harder? Do
students notice paths the water is taking? Introduce the concept of point
source pollution by “polluting” a small section of the watershed and observing
where the pollution travels to once it has rained. Examples of items to represent pollutants are
powdered drink mixes or vegetable oil.
Watershed
history
Students
may research the history of a particular piece of the watershed. One place to begin finding such information
are local newspaper files. Such files
may provide factual evidence of development along waterways, issues with
pollution, etc. Another source of
information is historical maps that can indicate changes in farming,
recreation, industry and housing. One
source of aerial maps that document historical changes is the USDA NRCS in
Students can trace the development of
towns and cities along the river.
Population clusters occur near rivers, and this can be traced back to
the Indians. For example,
Watershed health
Introduce the concept of “health” of a
watershed. There are numerous activities
on pages 17-23 that analyze the
health of water. What does it mean if a
watershed is “healthy”? What criteria do
students think can be used to consider the health of the watershed? Often times students will think that if
water is clear it is healthy, and if it is cloudy it is unhealthy. Whereas cloudiness is certainly a factor to
consider when discussing water quality, there are many more indicators that can
be examined and evaluated.
The boundaries of a watershed are determined
by the topography (the shape of the land surface). Examine topographical maps of the area to
locate any flowing water near your school.
Try to locate where they might originate and to determine where they
might flow to (eventually they should lead into the Housatonic River). Point out the variances in elevation as shown
on the map and notice the different thickness in the lines that represent
water. The thicker lines represent more
water flowing and are usually a lower elevation. This is because the water at a
lower elevation is moving more slowly on level ground, as the water moving
downhill tends to move more quickly (and in a thinner stream) as it is assisted
by the force of gravity more than the water flowing through a flatter area.
Students can investigate the use of
topographical (or “contour”) maps by creating a three-dimensional paper model
using topography. One way to do this is
to use the simplified version of the Housatonic River watershed and the
contours that are attached at the end of this guide as Appendix 1. You may want to copy the contour pieces on
card stock so that they are sturdier.
Provide students with the watershed map and look for any landmarks that
your students may know. Begin creating
your 3-D maps by coloring the bodies of water blue. Students can cut out the various contours and
layer them on top of the map. (A small
piece of clay between each piece is preferable to glue because it raises the
elevation).
Once students have an understanding of topographic
maps, you can try to get a USGS topographic map of the location of your school
and do the same activity. (They are
readily available at sporting goods stores because people going hiking use
them.) Correlate this activity with an
outdoor experience. Can your students
find the changes in elevation on a walk?
“Water is the most critical resource
issue of our lifetime, and our children’s lifetime. The health of our waters is the principal
measure of how we live on the land.”
Luna Leopold