WHAT IS A RIVER SYSTEM?
Every river is part of a larger system-a watershed, which is the land drained by a river and its
tributaries. Rivers are large natural streams of water flowing in channels and emptying into
larger bodies of water. This diagram shows some common characteristics of a river system.
Every river is different, however, so not all rivers may look exactly like this illustration.
The river source, also called the
headwaters, is the beginning of a
river. Often located in mountains, the
source may be fed by an underground spring, or by runoff from rain,
snowmelt, or glacial melt.
The river mouth is the place where a
river flows into a larger body of water,
such as another river, a lake, or an
ocean.
Upstream is in the direction of or
nearer to the source of a river.
Downstream is in the direction of or
nearer to the mouth of a river.
Wetlands are low-lying areas
saturated with water for long enough
periods to support vegetation
adapted to wet conditions. Wetlands
help maintain river quality by filtering
out pollutants and sediments, and
regulating nutrient flow.
A fully-developed floodplain is relatively flat land stretching from either side of a river, which
may flood during heavy rain or snowmelt. Built of materials deposited by a river, floodplain soil is
often rich in nutrients and ideal for growing food.
A tributary is a smaller stream or river that joins a larger stream or main river.
A watershed boundary, also called a drainage divide, marks the outer- most limit of a
watershed. A watershed is a tract of land drained by a river and its tributaries. Anything that
affects a watershed may eventually impact its tributaries and river as well as the water body at
the mouth of the river. People's actions within a watershed can affect the overall quality of its
rivers.
The main river is the primary channel and course of a river.
A meander is a loop in a river channel. A meandering river winds back and forth, rather than
following a straight course.
You can find an interactive version of this river system at www.NationalGeographic.com/geographyaction
“HUMAN RIVER” activity
Grade level: K-4 (Approximate age range: 5-9 years old)
Objectives: Through this activity, students will understand that rivers can be polluted and that
students' actions can make a difference in the water quality of rivers.
Relevant: U.S.
National Geography Standards: 14, 16, 18 (See table, below)
Materials
Photocopy of the River System Diagram (above)
Procedure
Show students the river system diagram and discuss the different components. Ask them where
they think they are located within a river system. Ask students to define litter. Have them name
items of litter. List the items on the blackboard. Ask, “What eventually happens to litter?” Help
students define "pollutants" and name different pollutants. Where have students seen litter?
Could litter or pollutants pose a problem for rivers?
Now, turn your class into a "human river." Have each student select one article (paper, book,
pencil, etc.) to represent a pollutant. Arrange students in a river pattern. "Tributary" students
lead into a line of "river" students, with an "ocean" student at the end of the line. Beginning with
students at the "source," have students pass their article to the next student, and so on, until the
"ocean" student holds everything. Students could say things such as, "I'm a dairy farmer, and
my fertilizer pollutes the river," or "I’m a power plant, and I'm heating the river water." How did
the students toward the middle and end of the river feel?
Remind students that pollution comes in different forms and from different places, but it could all
end up down a drain, where it threatens your river. Encourage students to get involved in
keeping rivers clean.
“USER FRIENDLY RIVERS” activity
Grade level: 5-8 (Approximate age range: 10-13 years old)
Objective: Students will understand their connection to rivers through watersheds. (This activity
will take one or two class periods.)
Relevant: U.S.
National Geography Standards: 1, 7, 15 (See table, below)
Materials
Photocopies of the River System Diagram (on the back of this poster) Students will break into
three groups. Each group will need:
- Blue enamel paint
- Miniature objects to simulate a model river system: e.g., Monopoly houses or hotels, small
plastic animals, trees, boats, cars
- Modeling clay
- Tempera paint
- Toothpicks and construction paper
- Sheet of plywood, or plastic or metal trays
- Water
Procedure: DAY ONE With students, examine the river system diagram. Have students
speculate where they are located in their own watershed. Where is the nearest river? The
nearest tributary? Remind students that the drawing is a generic representation of elements of
rivers, and that every river system is unique. Does a local river resemble the river in the
diagram?
Explain that rivers connect to land, and that people connect to rivers either directly or indirectly,
via their watershed. Ask, “How do people use rivers?” (drinking water, other fresh-water needs,
agriculture, industry, manufacturing, power, transportation, recreation) How does wildlife use
rivers? (food, habitat) Write students' answers on the board.
Now, divide students into three groups. Each group will build a model watershed from clay,
either on a sheet of plywood, or on a plastic or metal tray. Have students label parts of the river:
source, tributary, floodplain, meander, wetland, main river, mouth. Students should then paint
"river" areas with blue enamel paint and paint the "land" with tempera paint. Have students
place miniature objects on the model to simulate a model river system, or make figures from
construction paper and back them with toothpicks.
DAY TWO
Allow the model to dry overnight. The next day, have students pour a slow, steady stream of
water from the top of the mountain. As students pour water, discuss flooding and drought.
End by reminding students that what people put into the water, and how people use the water
available to them, is very likely to affect the quality of the water-and the quality of life of its
users-both locally and in other areas of a watershed.