1. Watersheds and Stream Order

2. Watershed Watershed: The land drained by a river or stream and
all of its tributaries.
Also known as a
Drainage Basin.
Watershed boundaries,
or divides, are typically
defined by the highest
elevation that drains
a stream.

3. Watersheds The rate at which water travels
through a watershed is determined
by factors such as:
its size (total surface area)
topography (flat or steep)
amount and type of vegetation
human development
The total amount of water that collects in
a river that drains the watershed is called
its Discharge.
Discharge is measured in meters3/second.
Total Discharge

4. Drainage Patterns Drainage patterns depend mostly on: (1) topography;
and (2)the type of
rock over which
streams flow.

5. Stream Order Stream Order: a system of classifying
streams and rivers based on their
relationship or position in the drainage
network.
Streams at the beginning of the system are called
first-order streams. First order streams receive water directly from a source such as a spring, lake,
melting snow, etc.
When two first order streams join, the resulting stream
is now classified as a second-order stream.

6. Stream Order Note: the stream order will increase only
when two like streams
join.

7. Slide 1: Stream Order Identify the proper stream order for each
of the following locations. 1 3 2 4

8. Slide #2 Lackawanna River Watershed Name the mountains that
act as the boundary/divide on
the eastern portion of the
Lackawanna River watershed.
How many counties
comprise the Lackawanna
River watershed?
The Lackawanna River
eventually flows into which
larger river?
Which type of drainage
pattern is dominant in the
Lackawanna River watershed?

9. Slide 3: Stream Gradient1 2 3
Place in order from fastest stream velocity to slowest the three locations
in the above diagram.
Which number would best illustrate a youthful stream?
Which number would best illustrate a mature stream?
Which number would carry the largest sediments (pebbles, cobbles, boulders)?
Which location is most likely to have extensive meandering?
Small sediments like sand and silt will be most likely found at which location?

10. Slide 4: Mississippi Watershed
Name the mountains
that cause the divide
on the western boundary
of the watershed.
2. Name the mountains
on the eastern boundary

11. Slide 5: PA’s Major Watersheds
1. Name the bodies of water that each watershed eventually drains into.
2. Which watershed includes the
Lackawanna River watershed?

12. Drainage Patterns Slide #6#B
Slide #6
Identify the type of
drainage pattern for
each example and;
Discuss how,
geologically, each
pattern forms. #C #D

13. Watershed Questions
1. Describe the relationship between stream order and the size of a watershed. 2. Describe how humans can affect a watershed. Give specific examples. 3. Describe how increased human development will affect how surface water travels through a watershed. 4. Compare a saturated and unsaturated geosphere and how each will influence the rate of surface water flow and discharge of a watershed.

14. Watershed Dynamics
All of the following watersheds are equal in surface area and receive equal rainfall. Compare and contrast each of the following watersheds: Discuss specifically, a. the rate of surface water flow through each watersheds (faster or slower) b. possible disruptions to flow. Give specifics! c. final discharge (more or less) 5. Flat (slope) terrain vs. steep (slope) terrain 6. Agricultural vs. forested land 7. Rural development vs. urban development