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Learning About Watersheds Using ArcGIS Online
Your Name: _____________________
Summary
This activity uses ArcGIS Online, a Webbased Geographic Information System
(GIS) (www.arcgis.com) as a tool for
analyzing the geography and science of
water from a spatial perspective. This
activity focuses on watersheds.
Detail
This activity is written for upper
secondary/university level but can be
used at the lower secondary level, and
can even be modified for primary levels.
It can be used in formal or informal
educational settings and in an
independent or whole-class format.
Time estimated: 1 class period of 50
Map of watersheds of the USA as determined by the EPA in
minutes. No previous experience with
ArcGIS Online. This is one of the investigations included in
GIS is necessary but (1) the geographic
this activity.
perspective is important, and (2) a
background in the topic investigated
would be helpful; at a minimum, a short discussion on the processes and phenomenon studied in each
investigation should be held at the beginning; such as “What are watersheds? Why are they important?
What influences the shape of a watershed? What in the cultural and physical environment has an
impact on watersheds, and how to watersheds impact people?“
Computer requirements: Web browser, Internet connection. Can be run in a computer lab setting, with
dedicated lab computers or students bringing their own tablets/laptops/devices, or with 1 computer in
front of the class with a projector.
Introduction
Water is a spatial subject: It can occur in solid, liquid, and gas phases on our planet and can easily move
between these three states. It moves through oceans, rivers, wetlands, and glaciers, and through the
hydrologic cycle at different rates. It is affected by long-term climate, everyday weather, hurricanes,
landforms, and air pressure. It has been channeled into settling ponds, water treatment plants, fields,
irrigation ditches, drainage ditches, canals, reservoirs, and through many other means by humans. It
acts as a change agent above, on, and below the surface of the Earth, affecting such phenomena as crop
Learning About Watersheds Using ArcGIS Online - Page 1 of 3
Author: Joseph J. Kerski – [email protected]
Copyright © 2012, Esri. http://edcommunity.esri.com
yields, aquifers, erosion, floods, stream sediment, soil chemistry, weathering, and much more. It
operates on a scale from local to global. Because water exists, moves, and acts at different scales and
affects so many other phenomena, the geographic perspective is critical to understanding it. And, GIS is
a very useful tool in which to study water in all of its forms, processes, and aspects.
Watch the movie “geographic reflections on water”: http://youtu.be/ntJvY4LixqQ
Name 3 connections between water and geography.
Because of these and a whole host of other factors, the geographic perspective is critical to
understanding water. GIS allows the geographic perspective to be applied to the study of water, and
ArcGIS Online provides a toolkit and rich set of data that allows you to study water right away.
ArcGIS Online Investigation
This investigation uses ArcGIS Online, on http://www.arcgis.com.
Investigating Watersheds
Do some background research and answer the following questions:
What is a watershed?
Why are watersheds important to the environment?
Why are watersheds important to people?
At ArcGIS Online (www.arcgis.com), click on “map.” Find and add the map “EPA Watershed Boundaries
NAD 83”. Expand the map layer to see the hierarchy of watershed details.
Note the nesting process: Subwatersheds nest within watersheds, watersheds nest within subbasins,
and so on.
What is the finest, most detailed watershed unit called? What is the largest watershed unit called?
The finer detailed watershed units do not draw until you zoom in to certain map scales. Enable the
popups for each of these watershed units and click on the map to complete the following questions:
In what region is Denver, Colorado?
In what subbasin is Ames, Iowa?
In what watershed is your own community?
Name at least two subbasins that have unusual shapes. Why do they have the shapes that they have?
Learning About Watersheds Using ArcGIS Online - Page 2 of 3
Author: Joseph J. Kerski – [email protected]
Copyright © 2012, Esri. http://edcommunity.esri.com
Be sure that topographic is your basemap. Rivers are one of the features in this basemap. Examine the
relationship of rivers to watershed boundaries. What is the relationship between rivers and
watersheds?
Some watershed region boundaries are prominent ridges and mountain ranges. Name two ridges or
mountain ranges that are also watershed boundaries. Give the location of these ridges (state, area
within the state, and nearby cities), and the regions that they divide.
Find the continental divide that divides the drainage of the Atlantic Ocean and the drainage of the
Pacific Ocean. Follow it from Montana to New Mexico. Is the continental divide also a watershed
boundary? How did you determine your answer?
Other watershed boundaries are more subtle on the landscape, and may not even be noticeable if you
were walking across the landscape in that area. Give the location of two of these “subtle” types of
watershed boundaries (name the state, area within the state, and nearby cities), and the watersheds
that they divide.
Zoom to Iowa. What two main rivers, that form the western (river A) and eastern boundaries (river B) of
the state, are the rivers that all of the streams in Iowa eventually drain into?
Approximately what percentage of Iowa drains into the river on the western side of the state?
Approximately what percentage of Iowa drains into the river on the eastern side of the state?
Identify the towns near the drainage boundary between river A and river B, from north to south, in
Iowa.
Synthesis
Name three things you have learned about watersheds through any of the above investigations.
Name three things you have learned about GIS through these investigations.
How has the spatial perspective about watersheds influenced your understanding of them?
If time permits, use the presentation mode in ArcGIS Explorer Online to create a presentation of your
own choosing where you explain what you have learned about a specific aspect about watersheds. Give
your presentation to your peers, save it, and share it with others.
Additional Explorations
You have explored a few aspects of watersheds from a spatial perspective, but much more could be
done. Write your own question about watersheds, investigate it, and answer it! 
Learning About Watersheds Using ArcGIS Online - Page 3 of 3
Author: Joseph J. Kerski – [email protected]
Copyright © 2012, Esri. http://edcommunity.esri.com