In Investigation One, you will explore the abiotic factors of water velocity and discharge that affect watersheds. During this Investigation, you will:

1. Create a model of the headwaters of a watershed.
2. Test the effect of water flowing at a slow, medium, and high velocity on discharge.
3. Calculate discharge using the following formula:

Discharge = Volume(ml) / Time(s)

In Investigation Two, you will further investigate watersheds and sedimentation. During this Investigation, you will:

1. Create a model of a watershed and test the amount of sedimentation and turbidity at various water velocities.
2. Use a spectrophotometer to measure the transmittance of light in water samples of varying water velocity and turbidity.

In Investigation Three, you will consider abiotic factors such as temperature, water velocity, and salinity in a watershed and how they affect dissolved oxygen levels. During this Investigation, you will:

1. Use an Oxygen Meter to measure the dissolved oxygen levels in water samples of varying temperatures.
2. Use an Oxygen Meter to measure the dissolved oxygen levels in water samples of varying salinity (salt concentrations).
3. Use an Oxygen Meter to measure the dissolved oxygen levels in water samples of varying water velocities.

This Performance Assessment is designed to allow students to solve a problem using the:

• concepts with which they have become familiar during the previous three Investigations, and
• procedures used during the previous three Investigations.