Urban Watershed Mitigation Design
Performance Expectation: HS-ESS3-4: Evaluate or refine a technological solution that reduces impacts of human activities on natural systems.
Part 1: Engage (Anchoring Phenomenon)
The Dead Zone A major urban river normally sustains a diverse local ecosystem of fish and wildlife. However, after heavy spring rains washed over nearby agricultural fields and city streets, the river experienced a massive, foul-smelling algal bloom. Within days, thousands of dead fish floated to the surface. City officials have secured a $10.0 million budget to implement a combination of technological solutions to prevent this from happening next year, but they need your team of engineers to determine the most effective and reliable strategy.
- What do you notice? _____
- What do you wonder? _____
- Why might heavy rains in urban and agricultural areas lead to an algal bloom and fish die-off? _____
Part 2: Explore (Simulation Investigation)
Access the Urban Watershed Mitigation Design simulation. Your goal is to keep the Pollutant Load (N/P) below the critical threshold (50%) and maximize the Biodiversity Index over a 10-year period, without exceeding the $10.0M budget.
Available Technological Refinements:
- Constructed Wetlands (Levels 0-3): Natural filtration; high land use; high effectiveness.
- Advanced Wastewater Filtration (Levels 0-3): High reliability; very high financial cost.
- Urban Green Infrastructure (Levels 0-3): Moderate cost; aesthetic and runoff benefits.
- Agricultural Riparian Buffers (Levels 0-3): Low cost; requires landowner cooperation.
Instructions:
- Run a Baseline Test: Set all refinements to Level 0. Click “Run Simulation (10 Yrs)”.
- Record the final Pollutant Load and Biodiversity Index for the baseline in the data table.
- Test 3 different mitigation strategies by adjusting the sliders. You must stay at or below the $10.0M budget.
- For each strategy, run the simulation, and record the final data and system tradeoffs (Reliability and Land Required).
| Trial | Constructed Wetlands | Adv. Filtration | Green Infra. | Ag. Buffers | Total Cost ($M) | Final Pollutant Load (%) | Final Biodiv. Index | Reliability | Land Required |
|---|---|---|---|---|---|---|---|---|---|
| Baseline | 0 | 0 | 0 | 0 | $0.0 | ||||
| Strategy A | |||||||||
| Strategy B | |||||||||
| Strategy C |
Part 3: Explain (Sensemaking)
Using the data you collected, answer the following questions:
- Analyze the Baseline: What happens to the natural system if no technological refinements are implemented? _____
- Compare Strategies: Which of your tested strategies was most effective at stabilizing the natural system (lowering pollution and raising biodiversity)? Cite specific data from your table. _____
- Identify Tradeoffs: Describe a tradeoff you encountered when trying to maximize effectiveness while staying within the $10.0M budget. Did a highly effective solution come with negative constraints (like high land use or lower reliability)? _____
- Scientific Reasoning: Explain the scientific principles behind how one of these technologies (e.g., Constructed Wetlands or Advanced Filtration) reduces the impact of human activities on the watershed. _____
Part 4: Elaborate / Evaluate (Argumentation & Modeling)
Final Recommendation to City Officials Based on your prioritized criteria (effectiveness, cost, reliability, land use) and student-generated evidence from the simulation, write a formal proposal recommending your best design solution.
Your proposal must include:
- A clear statement of your recommended refinement combination (e.g., Level 2 Wetlands, Level 1 Filtration, etc.).
- Evidence from your data table showing how this solution stabilizes the natural system (reduces pollutant load and supports biodiversity).
- An explicit analysis of the costs and benefits of your proposed solution, addressing both the $10.0M financial constraint and environmental/social impacts (like land availability and reliability).
Proposal: ___ _____ _____ _______
Extension Options
- Physical Modeling: Have students build a physical model of a constructed wetland using sand, gravel, and plants to physically test filtration rates.
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Local Watershed Analysis: Use Google Earth or a local municipal GIS system to map out potential areas where green infrastructure could be implemented in your own community.
Teacher Notes & Alignment
Estimated Time: 45-60 minutes Materials: Internet-connected device, Urban Watershed Mitigation Design simulation, student handout.
NGSS Alignment:
- Performance Expectation: HS-ESS3-4: Evaluate or refine a technological solution that reduces impacts of human activities on natural systems.
- Science and Engineering Practice (SEP): Constructing Explanations and Designing Solutions (Design or refine a solution to a complex real-world problem based on scientific knowledge, student-generated sources of evidence, prioritized criteria, and tradeoff considerations.)
- Disciplinary Core Idea (DCI):
- ESS3.C: Human Impacts on Earth Systems (Scientists and engineers can make major contributions by developing technologies that produce less pollution and waste and that preclude ecosystem degradation.)
- ETS1.B: Developing Possible Solutions (When evaluating solutions, it is important to take into account a range of constraints, including cost, safety, reliability, and aesthetics, and to consider social, cultural, and environmental impacts.)
- Crosscutting Concept (CCC):
- Stability and Change (Feedback (negative or positive) can stabilize or destabilize a system.)
- Influence of Science, Engineering, and Technology on Society and the Natural World (Engineers continuously modify these technological systems by applying scientific knowledge and engineering design practices to increase benefits while decreasing costs and risks.)
Evidence Statement Mapping:
- Using scientific knowledge to generate the design solution: Students interact with the simulation to identify how agricultural and urban runoff impact the system (Part 1/2) and use scientific reasoning to describe how technological refinements stabilize the natural system by reducing pollution (Part 3).
- Describing criteria and constraints: Students must balance a $10.0M budget constraint against effectiveness, land required, and system reliability (Part 2/3).
- Evaluating potential refinements: Students test multiple solutions, evaluating them for their effects on the overall stability of the natural system (biodiversity and pollution tracking) and selecting the optimal cost-benefit ratio for their final proposal (Part 4).