1. Calculating Loss – Water Runoff

2. 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?

3. 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?

4. 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.

5. 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.

6. Explain to your face partner ..
What is meant by groundwater?
How does it get into the ground?

7. 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.

8. 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

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

10. Converting
Step one: Convert inches of rain into cm of rain
_____________ (inches per year of rain) x 2.54cm = ______________cm of rain per year

11. Step 2: Converting acres into cm2
# acres x ft2 x (conversion #6)2 x (conversion #1)2 = # cm2
_________ acres x ft2 /1acre x (12 inches/1ft)2 x (2.54 cm/1 inch)2 = ___________________ cm2

12. 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.

13. 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

14. Step 5: Converting liters to gallons
Step 4 answer x conversion 5 = # gallons
_______________ liters x 1 gallon/3.8 liters = _______________________ gallons

15. . Step 6: Finding the absorption amount
Step 5 answer x percent absorption = # gallons lost to runoff
________ gallons x 50% absorption = _______________________ gallons

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

17. 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.)

18. 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?