Calculating Loss

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• Calculating Loss Water Runoff

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What is your prior knowledge of groundwater?

• Turn to your shoulder partner and answer the
  following questions
• Does your family have to haul water? If so, how
  often and how much at a time do you have to haul?
• Do you know someone who hauls water?
• Do you know where your water comes from?
• Have you ever run out of water?

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Calculating Runoff

• Think, Pair, Share
• Where do we see water running off after a
  rainstorm?
• How can we calculate how much water is lost due
  to runoff?

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Groundwater What are we doing to our planet?

• In order for groundwater to be replenished,
  precipitation must be absorbed by the ground.
  People, worldwide, realize there is a need for
  stable and adequate water supplies. Yet, in many
  countries, including the US, people are creating
  more urban areas. The development of our rural
  land into cities is one cause for a lack of a
  stable and adequate fresh water supply in the
  future.

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Why is this important to you?

• Most of the water in the ground comes from
  precipitation that infiltrates downward from the
  land surface.
• Large amounts of water are stored in the ground.
• Today we will calculate the yearly runoff created
  by a parking lot, and calculate the loss of water
  that would have entered the groundwater system.

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Explain to your face partner ..

• What is meant by groundwater?
• How does it get into the ground?

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Calculating Runoff

• Square inches or cm are AREA measurements, as is
  an acre. But, if square inches are multiplied by
  another inch (or cm), the resulting unit is a
  CUBIC inch, which is a unit of volume, just like
  gallons, liters, etc.
• This volume unit is what we need to find. Since
  cubic inches do not translate into gallons, we
  must convert inches to cm, cm to liters, then
  liters to gallons.

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Here are the conversion units you will need.

• 1) 1 inch 2.54 cm
• 2) 1 cubic inch (2.54 cm)3
• 3) 1 cm3 1 ml
• 4) 1000 ml 1 liter
• 5) 1 gallon 3.8 liters
• 6) 1 foot 12 inches

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Conversion example

• 96 eggs ?? Dozen
• we know that 12 eggs 1 dozen
• 96 eggs x 1 dozen the eggs unit cancel
• 1 12 eggs
• 96
• 12
• 96 dozen 8 dozen
• 12
• Now we have successfully used a conversion factor
  to go from one unit to another!!

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Converting

• Step one Convert inches of rain into cm of rain
• _____________ (inches per year of rain) x 2.54cm
  ______________cm of rain per year

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• Step 2 Converting acres into cm2
• acres x 43650 ft2 x (conversion 6)2 x
  (conversion 1)2 cm2
• _________ acres x 43650 ft2 /1acre x (12
  inches/1ft)2 x (2.54 cm/1 inch)2
  ___________________ cm2

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• Step 3 Finding the volume in centimeter and in
  milliliters
• Step 1 answer x Step 2 answer
• ___________ cm x _________ cm2
  __________________________ cm3, which is the same
  as milliliters.

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• Step 4 Converting cm3 to liters
• Step 3 answer x conversion 3 x conversion 4
  liters
• ____________ cm3 x 1ml/cm3 x 1 liter/1000 ml
  ________________________ liters

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• Step 5 Converting liters to gallons
• Step 4 answer x conversion 5 gallons
• _______________ liters x 1 gallon/3.8 liters
  _______________________ gallons

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.

• Step 6 Finding the absorption amount
• Step 5 answer x percent absorption gallons
  lost to runoff
• ________ gallons x 50 absorption
  _______________________ gallons

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Pair up

• For one minute share what surprised you most
  about how rain runoff affects groundwater.
• Be prepared to share with the class.

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Homework

• You will need to measure the base of your house
  and any driveways, storage building, etc., that
  would keep water from soaking into your ground.
  
• Then you need to measure the total size of your
  lot. If you live in a multifamily dwelling
  (example an apartment), approximate the size of
  the land in the complex that would be your yard.)
  

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Ticket Out the Door

• Write 3-5 sentences about
• Why we should worry about runoff?
• How we could design parking lots to help solve
  the problem of water loss through runoff and help
  replenish our groundwater system?