Consumers Guide to Efficient Irrigation

"You never miss the water till the well runs dry"

Isn’t it the truth? Water is a necessity that is often taken for granted until the well runs dry. The Carolinas Irrigation Association is dedicated to the conservation of this most precious of resources by educating the consumer about proper irrigation practices. This information will give you a basic understanding of how the components in your system work.

Get To Know Your Sprinklers
What type of sprinklers do you have in your yard? You might be surprised to learn that this question is one of the most important when it comes to the operation of your automatic irrigation system. Sprinkler systems primarily use a combination of three very different types of irrigation components:

1. Sprayheads - These sprinklers have a fixed spray pattern that covers a radius up to 15 feet. They can be used on spring-loaded bodies that can pop-up from 2 to 12 inches or on fixed risers. They typically have a precipitation rate of 1.5 to 1.7 inches per Hour (In/Hr).
2. Rotors - These sprinklers rotate when popped up and usually have a single stream that covers a radius from 25 to 40 feet. They typically have a precipitation rate of 0.3 to 0.5 In/Hr.
3. Drip Irrigation - Drip irrigation comes in a variety of forms, the most common of which is called an emitter. Emitters have a flow ranging from 0.5 gallons per hour (gph) to 24.0 gph. Drip irrigation is used on groundcover, shrubs and trees and it’s precipitation rate is determined by the emitter used and the area covered. Drip can also utilize drip sprays, which can run with the emitters.

As you can see, it’s necessary to make sure these components are run on different zones (valves) due to their vast differences in performance.

Get To Know Your Controller

Your controller (otherwise known as a timer or clock) tells your sprinklers when and how long to operate. After you have determined what type of sprinklers you have on each zone, you need to determine how long to run your system. There are many factors involved in scheduling your automatic irrigation system:

1. Infiltration Rate - This factor will tell you how much water your soil can soak up before run-off occurs. This number can vary from 0.2 Inches per Hour (In/Hr) for clay soils to 2.0 In/Hr for sandy soils. Any slope in your yard will decrease this rate and should also be taken into consideration.
2. Water Days - This tells your controller which days of the week you want your sprinklers to run. In most cases, you will operate your system two or three days per week.
3. Run Time - Your run time tells your zones how long to run. This run time can be determined by taking the precipitation rate of each zone and calculating how long it should run to apply 1⁄2" to 1" of water per week.* For example: If your rotors have a precipitation rate of 0.5 In/Hr., you would need to run the rotors on that zone 1 hour per week to achieve 1⁄2" of water per week. If you were to run this zone 3 days per week the run time would be 20 minutes (1 hour = 60 minutes divided by 3 days/week). Another example would be a sprayhead zone that has a precipitation rate of 1.5 In/Hr. To apply 1⁄2" of water per week you would need to run this zone for 20 minutes per week. If you ran this zone for 20 minutes per week. If you ran this zone 2 days per week the run time would be 10 minutes (20 minutes divided by 2 days/week).
4. Start Time - Your start times on your controller tell the zones what time of the day the run times previously mentioned should begin operation. The best time to run your sprayheads and rotors is between 2 a.m. and 10 a.m. to cut down on the loss of water due to evaporation during the heat of the day. Drip irrigation can run virtually anytime because of its relatively low application rate. Proper mulching of plant beds will insure that your plants use the water efficiently.
5. Water Budgeting - Some controllers offer the ability to adjust run times by using the water budget feature. This feature adjusts all run times on a program by a percentage. For example: If all your zones are scheduled to run for 40 minutes and you adjust the water budget to 75%, all the zones on that program will run for 30 minutes (40 minutes times 75%). This comes in handy when making seasonal adjustments to your system.

*Note that your irrigation system is to be used only as a supplement to natural rainfall. The use of a rain sensor should be implemented to shut off your system when there has been adequate rainfall. The 1⁄2" to 1" per week mentioned is a worst case scenario when there is NO rainfall throughout the week.

Maintain Your System

The final key to an efficient irrigation system is to keep it properly maintained. Your system should be checked out at least twice a year by a qualified irrigation contractor. Each spring you should have the system inspected to ensure there was no damage done over the winter months. This should include checking head operation for proper adjustment, proper valve andcontroller operation and programming. After the fall, your system should be shut down during the winter to protect the components from freeze damage. Proper winterization should include draining the system down and turning the controller to the off position.

It’s More Than Just Water…

The bottom line to using your sprinkler system properly is to be conscious of the water that you’re using. The more you fine tune it, the more efficient it will be. Don’t be afraid to ask questions of your local professional irrigation contractor when it comes to programming and operation. If your system is designed, installed and maintained properly, it will provide many years of service. After all, it’s more than just water…it’s LIFE!

Call the Carolina's Irrigation Association at 800-682-7774 for a qualified professional irrigation contractor in your area.