Got Water?
Module 2

Lesson 3 - The Can Method for Determining Sprinkler Output, Activity
Acknowledgement: Taken from "Living on the Land 2001"

Materials Needed:

• 10 or more straight-sided containers such as soup cans (at least 4-6" deep and all having the same diameter)
• A pencil
• A ruler
• A calculator

1. Pick a calm time of day, such as early morning. Avoid gusty days.
2. Place the cans randomly at different locations in the lawn or pasture you want to test.
3. Run your sprinklers for 15 minutes. If the water begins to puddle or run off the lawn before the 15 minutes are up, write the number of minutes the sprinkler ran before runoff occurred. If runoff occurred, wait for one (1) hour and then try to complete the 15 minutes.
4. Pause for a moment. Check your cans. There should be about the same amount in each can. You may need to make some minor sprinkler adjustments, such as turning the screws in the center of a nozzle to restrict or increase the water spray. However, if the water levels are more than 50 percent different (for example, one can contains ¾ inch water and another contains ¼ inch of water), you might need some major repairs. If so, call in a professional.
5. The next step is to calculate the average amount of water, by depth, being applied. Combine the water from several cans into one can. It may take more than one can to collect all the water. Be careful not to spill any of the water.
6. Next, place the cans of water on a level surface. With your ruler, measure the depth of water in each can and record the depths here: 
               _____________        _____________            _____________
   
7. Using your calculator, add the depths (in inches) and divide by the total number of cans used in the test. This will determine the average inches of water your sprinkler system applied. For example: You used a total of 15 cans in your test. You were able to pour all the water into four (4) cans. The first can measured 2 1/2 inches; the second measured 2 inches; the third measured 2 ¼ inches, and the last measured 1 ¾ inches.

Adding together the depths: 2 ½ + 2 + 2 ¼ + 1 ¾ = 8 ¾ inches total. This is the same as 8.75 inches. Divide 8.75 inches depth by the 15 cans used to find that you are applying about 0.6 inches of water in 15 minutes.

8. Record the average water depth for your system here:_____________

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