Mapping Your Permeable Surfaces

Context: Permeable surfaces are surfaces that allow water or other liquids to pass through them. They can be anything from grass or a garden bed, to special pavement that allows water to soak through it. Permeable surfaces can help reduce the burden on stormwater systems by allowing more water to go directly into the ground, instead of running into the sewer. This is why in Detroit there is a drainage charge paid by residents, which is based on the amount of hard surfaces on your property. We will be taking a look at the importance of permeable surfaces, and thinking about our own homes.

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Goals: Grade Level: 6-12

• Better understand permeable surfaces

• Critically think about our own homes’ permeable and impermeable surfaces

Supplies:  Time: 40 minutes

• Paper and drawing utensil 

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Instructions:

• Take a couple minutes to watch the following video on pervious and impervious surfaces 

• https://www.youtube.com/watch?v=iEVC3LYogMQ

• When you are done, think about where you live. Try to imagine a birds eye view of your own home and yard and where the permeable and impermeable surfaces are. Then, take a piece of paper and draw out what you think it is like. Maybe color in the permeable areas. It doesn’t have to be perfect, just give you a visual representation of what you think your home is like.

• For mine, I colored the permeable surfaces green.

• When you are done making your drawing visit the following website, and look up your address. You’ll be able to see how the City of Detroit determines your drainage charge. Which directly relates to the amount of permeable and impermeable surfaces on your property. 

• https://detroitmi.maps.arcgis.com/apps/webappviewer/index.html?id=ce1eaf8deee347439687dcafe822372c

• Lastly, read and look over this short page looking at the impact of permeable surfaces. 

• https://www.udel.edu/academics/colleges/canr/cooperative-extension/fact-sheets/permeable-impermeable-surfaces/

Take a few minutes to read over and answer the reflection questions

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Reflection Questions

• According to the City of Detroit, did you have more or less permeable surfaces at your home than you thought?

• What happens to contaminants like oil, dog poop, fertilizer or other chemicals when it rains on impermeable surfaces? Where do they go?

• When it rains, do you notice any flooding around your home or neighborhood? If so, do you think having less impermeable surfaces would help? Why?

• In Detroit, we have a combined sewer system, which means both the water we use in our homes and stormwater go into the same pipe. If it rains too much in Detroit the sewer can't handle it all, and some of that dirty water gets dumped directly into the Detroit river. How could the amount of permeable surfaces in the city affect this?

(For more information about CSOs, check out our activity: https://www.youthenergysquad.org/post/where-does-our-wastewater-go )

• In Detroit you can get your Drainage Charge reduced by 25% just by making sure the downspouts from your gutters empty onto your lawn! How else could you reduce the amount of water going into the storm drain from your home?

• A major impact of climate change in Detroit will be increased high rain events. How does this relate to impermeable surfaces, and making changes to permeable ones?

• How can the City of Detroit encourage businesses and homeowners to increase the amount of permeable surfaces on their property?