Big Ideas
Plants, trees and soil create a natural buffer for waterways by absorbing runoff, filtering water and controlling erosion. This is part of the natural water cycle
Cities like Philadelphia have large amounts of impermeable surfaces (pavement, rooftops, etc.) that interrupt the natural flow of water across the land and into the ground.
There are ways to work with nature to balance this out.
Summary
Plants, trees and soil protect our waterways by absorbing runoff, filtering water and controlling erosion. Replacing them with buildings and roadways can lead to flooding and an excess of water pollution from stormwater runoff. Returning the landscape to its natural state can help control these problems. Soil composition and plants are studied to determine the best natural solution
Engage
Address the Essential Question at the beginning and end of this Unit
How can we create sustainable urban design solutions that work with the natural water cycle?
Use the Turn and talk SLIDE DECK prompts.
The Natural Water Cycle Graphic will help them review the 8 stages of the natural water cycle as it interacts with land and water so that they can explore permeability and impermeability. They will focus on the infiltration and runoff of precipitation and how it impacts local waterways.
Plants, trees and soil create a natural buffer for waterways by absorbing runoff, filtering water and controlling erosion. Water cycles around and around on Earth—our lives and all life on Earth depends on water. (We can only last three days without water!
Explore and Explain
Important Note: In Unit One students explored soils and found out that different types of soil “cleaned” the water with varying efficacy as the water filtered through the soil. They also saw the relationship between a natural riparian buffer and run-off. Here the students will explore the relationships between plants and pervious/impervious surfaces and they will begin to more thoroughly explore the relationship between plants, permeability and run-off.
Two hands-on activities (see student instructions in the SLIDE DECK) :
Mason Jar Plant Experiment (allow 3 weeks for this experiment)
Ground Cover Experiment
After these experiments, show students the real world scenarios identified with links in the SLIDE DECK or in the MATERIALS Tab
Elaborate
Choose one of the hands-on experiments (see the SLIDE DECK for suggestions) to observe the benefits of plants and soil related to absorption and runoff and to help answer the question: .
Why do plants and pervious surfaces play such an important role in mitigating polluted and/or excessive stormwater runoff ?
Now look more closely at the structure of plants using food dye with celery or a carnation through research and experimentation, and make a model or diagram of the structure and how it relates to stormwater.
Identify a problem related to impervious surfaces and find a solution
Extensions
Here are some additional MWEE opportunities regarding the role of plants in the water cycle through transpiration.
Research the possibility of Live Staking to determine whether this strategy is feasible at the school property. Live Staking Fact Sheet
Identify trees that are planted in the Million Tree Effort. Explain the benefits of those species. Plant One Million Trees and Arbor Day Tree Guide.
Teacher Support
Essential Question:
How can we create sustainable urban design solutions that work with the natural water cycle?
Guiding Questions:
Engage:
How does the natural water cycle work in our watershed?
Can we see the natural water cycle at work in the city?
Explore & Explain:
What disrupts the natural water cycle in our cities?
Students will be able to:
Engage:
Draw and describe in detail how permeable surfaces absorb water into the ground, or runoff into the nearest waterway as part of the natural water cycle.
Observe and document evidence of the natural water cycle at work in the city.
Elaborate:
Draw and explain what happens to the water when it encounters impermeable surfaces (teacher note: it runs off into storm drains, but does not get absorbed, carries litter, etc.).
Explore and Explain
Mason Jar Data Sheet (3-week experiment)
Narcissus (Paper white) bulbs
Mason Jar
Gravel
Eyedropper or straw
Water
Pervious and Impervious samples of ground cover such as clay, sand, top soil, gravel, concrete
Mason Jars
Percy Street PWD Green Infrastructure: Percy Street and Porous Paving
East Falls Parking Lot East Falls Green Infrastructure Project
Saylor Grove Saylor Grove Storm Water Wetland
Philadelphia Schools with developing or existing green school yards
Elaborate
Plants or Seeds (if time)
Terrariums (recycle soda bottles )
Variety of soil mixtures
Celery or carnation and food coloring
Water
Extensions
BASIC TERMS
Absorbency adjective
Capable of taking in/soaking up moisture
Infiltration noun
The seepage of water into soil or rock
Impervious adjective
Not allowing liquid to pass through
Permeable adjective
Allowing liquids and gases to pass through
Pervious adjective
(Of a substance) allowing water to pass through, permeable.
Porous adjective
Of a rock or other material having minute spaces or holes through which liquid or air may pass.
ADVANCED TERMS
Evapotranspiration noun
the process in which water is transferred from the land to the atmosphere by evaporation from the soil and other surfaces and by transpiration from plants
Infrastructure noun
The underlying foundation or basic framework
Transpiration noun
Process by which plants absorb water through roots and then give off water vapor through pores in their leaves.
Vascular noun
Of or relating to a channel for the conveyance of a liquid.
Address the Question:
Can we create sustainable urban design solutions that work with the natural water cycle?
Revisit this question at the end of the Unit and have students compare their pre-post responses and reflect on their learning.
Draw and describe in detail how permeable surfaces absorb water into the ground, or runoff into the nearest waterway as part of the natural water cycle.
Observe and document evidence of the natural water cycle at work in the city.
Draw and explain what happens to the water when it encounters impermeable surfaces (teacher note: it runs off into storm drains, but does not get absorbed, carries litter, etc.).
PA STEELS
Standards 3.4.6-8.C Develop a model to describe how watersheds and wetlands function as systems, including the roles and functions they serve.
Related Standards
EfS EU 11 Enduring Understandings – We must operate within the natural laws and principles rather than attempt to overcome them. It is non-negotiable.
Student Materials
Student Worksheet