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Investigation 1 – PreLab









Watershed coordinators monitor industrial pollution, habitat destruction, and excessive diversion within local watersheds. They then develop and lead efforts to keep the local watershed and its ecosystems healthy for years to come.


This Investigation is designed to help you to answer the following Focus Question:

  • How do the abiotic factors of water velocity and discharge affect a watershed?

Note: This question is located in your SDR at the beginning and end of the Investigation.



As a class, read the Background(s) in the Investigation.  When finished, discuss the following concepts as a class:

  • One of the abiotic (non-living) factors that is important to the structure and function of watersheds is water velocity.
  • Velocity is distance per time and is usually measured in meters per second (m/s).
  • A second abiotic factor that affects watersheds is discharge.
  • The discharge of a stream or river is the amount (volume) of water that passes a point in a certain amount of time.
  • When scientists measure water velocity, they cannot measure it directly. Instead, they measure a distance on a stream and determine the amount of time that it takes an object to travel (float) that distance.



The following list includes Key Terms that are introduced in the Investigation Background(s). They should be used, as appropriate, by teachers and students during everyday classroom discourse.

  • Watershed
  • Velocity
  • Discharge

Note: Additional words may be bolded within the Background(s). These words are not Key Terms and are strictly emphasized for exposure at this time.


  • Complete the Recall section in your SDR.
  • What is velocity?
  • What happens when water velocity in a stream increases?
  • What could make water velocity increase?
  • Play the video below. Remember to follow along with your SDR and make any notes that you think might be helpful.
  • After the video, divide into lab groups to discuss strategy for the lab. For example, you may assign certain group members to perform specific functions during the lab.

Note: The purpose of the video is to allow you to anticipate the laboratory experience you will soon encounter. You should leave this PreLab session with a firm idea of what to expect and how to perform in the lab.

Note: Homework is posted below the video.



You should review the Investigation and video in preparation for the Lab.