Hydrosphere: Runoff Effect

Investigate the relationship between land use and runoff by measuring the Conductivity.

Runoff Graph

Students use conductivity data to identify runoff from different model watersheds. Inquiry question: How does agriculture effect water quality?

Lab Summary:

Increased runoff due to urbanization and development can have dramatic effects on local streams. As surfaces that were once covered with soil and vegetation are increasingly paved over for roads and housing, rainfall runoff is accelerated. Clearing natural vegetation for cattle grazing and agriculture also affects the contents of runoff. Chemicals and other contaminants accumulate on paved surfaces and are swept into streams through runoff. The increase in dissolved solids in water results in higher conductivity in streams.

In this activity, students will build two mini-watersheds: an agricultural site and a pristine wilderness near headwaters of a watershed. Students will then use a conductivity sensor to measure the conductivity of runoff in each of these contexts. Students will grasp how different land use practices affect the quality of water runoff.

Download free labs:

(student versions)

Computer-based lab (PDF, 629 KB)

Xplorer GLX-based lab (PDF, 64 KB)

Method:

Use a Conductivity Sensor to measure the conductivity of runoff from two mini-watersheds.

Here's What You Need:

Required for Xplorer GLX-based lab:

(See lab download for computer-based lab requirements, which may differ)

Probeware

Other Materials

  • Large, Flat, Low-sided Rectangular Pan
  • Watering Can or Squeeze Water Bottle
  • Protective Gear
  • Clean Plastic Bottles with screw tops (2)
  • Labels and Labeling Pens
  • Cheesecloth
  • Sand, 2.0 kg
  • Soluble Fertilizer, 20.0 g
  • Water, Distilled, 1.0 L

Lab Manual:

The computer-based activity is included in Explorations in Earth and Environmental Science (PS-2809). The Xplorer GLX-based lab is included in Earth and Environmental Science with the Xplorer GLX (PS-2821A). Both manuals are complete with Teacher Information pages, student instructions and handouts, and sample data.

For your convenience, we offer bundles which provide the probeware for the activities in the manual. For more, please see:
Computer-based Earth and Environmental Science Lab Manual and Bundles
Xplorer GLX-based Earth and Environmental Science Lab Manual and Bundles