California Coastline

Phenomenon: Coastal Flooding During High Tides in California

Several coastal cities in California, such as Imperial Beach, Long Beach, and San Francisco, are experiencing “sunny day flooding”—flooding during high tides even in the absence of rainfall. This phenomenon offers an ideal context for integrating all 7 NGSS Crosscutting Concepts (CCCs).

Progression of Guiding Questions by Crosscutting Concept

1. Patterns

• Guiding Question: Where and how often are high-tide floods occurring along California’s coastline?

• CCC Focus: Recognizing trends in sea level and flooding frequency.

• Student Activity: Graph and map historical flood data from NOAA stations (e.g., San Francisco, La Jolla).

2. Cause and Effect

• Guiding Question: What environmental and human factors are causing high-tide flooding to increase in California?

• CCC Focus: Understand contributions from thermal expansion, melting ice, and urbanization.

• Student Activity: Create a flowchart showing links between causes (e.g., global warming) and local effects (e.g., street flooding).

3. Scale, Proportion, and Quantity

• Guiding Question: Why does a small sea level rise (e.g., 6 inches) lead to a large increase in flood events?

• CCC Focus: Explore the concept of tipping points and nonlinear impacts.

• Student Activity: Analyze tide gauge data or use digital simulations to compare effects of 0.5, 1, and 2 feet of sea level rise.

4. Systems and System Models

• Guiding Question: How do California’s natural and engineered systems interact to influence flooding risk?

• CCC Focus: Model interactions between tides, groundwater, infrastructure, and rainfall.

• Student Activity: Construct a system diagram for a city like Long Beach, showing how ocean tides, sewer systems, and land elevation contribute to flooding.

5. Energy and Matter

• Guiding Question: How does energy from the atmosphere contribute to sea level rise on the California coast?

• CCC Focus: Trace how added heat energy affects ocean water and ice sheets.

• Student Activity: CER writing: Students use evidence to explain how energy input changes the amount and movement of water.

6. Structure and Function

• Guiding Question: How do seawalls, wetlands, and green infrastructure function to reduce flooding?

• CCC Focus: Evaluate how design affects performance.

• Student Activity: Compare different coastal adaptation strategies (e.g., San Francisco’s Embarcadero Seawall vs. nature-based solutions in Southern California).

7. Stability and Change

• Guiding Question: How are California’s coasts changing over time, and what actions can promote long-term stability?

• CCC Focus: Analyze trends and evaluate responses to environmental change.

• Student Activity: Use tools like Cal-Adapt to model projected sea level changes and draft a policy brief with proposed mitigation or adaptation strategies.