Grade 8 · Water Systems · Watersheds and Water Sustainability
Investigate a Watershed Decision
A watershed is the land area that drains water to a shared outlet. Water links upstream and downstream places, communities, ecosystems, groundwater, infrastructure, and the atmosphere.
Visual model
See how the ideas connect
Describe Earth's water distribution and circulation
Use watershed thinking
Connect quality scarcity and management decisions
Watersheds and Water Sustainability
For students
Notice, predict, explain
Choose one part of the model. Predict how it connects to another part, then use the lesson evidence to explain your thinking.
For teachers
Pause for science talk
Show the model before the explanation. Ask “What do you notice?” and “What might change?” Then revisit student ideas after the worked example.
The big idea
Water decisions travel through connected systems
Precipitation, runoff, infiltration, groundwater, evaporation, water use, treatment, land cover, pollution, and climate interact across watershed boundaries and over time.
Work it through
Evaluate a new paved development
- Step 1 More impervious surface can increase rapid runoff and reduce infiltration that replenishes groundwater.
- Step 2 Runoff may carry sediment, nutrients, salt, oil, and warmer water into streams, changing water-quality indicators and habitat.
- Step 3 Wetlands, permeable surfaces, vegetation, careful storage, monitoring, and reduced contaminant use can reduce impacts.
- Step 4 A responsible plan considers downstream communities, water treatment, drought and flood risk, Indigenous rights and knowledge, costs, and long-term climate conditions.