Travis Irrigation Plans and Supply


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Water Schedule FAQs

We sincerely hope you will find helpful information in these pages. Be sure to check our indexed Frequently Asked Questions (FAQ) and Answers pages first to see if your questions have already been answered. If you can't find the answer you are looking for, submit your question to and we will consider including your question in our FAQs pages. Unfortunately, due to the volume of questions we receive, we can't answer them all personally, but we'll let you know if we decide to include your question and answer on our site.

When should I water?
You should water when your plants show signs of needing water. If you water too often, you will waste water, promote shallow root growth and encourage the growth of fungus which can damage your plants or require the regular application of fungicide.
How long should I water?
Water long enough to saturate the ground to a depth of several inches for lawns. For shrubs and trees, you should water longer and less often. Watering for short periods of time leads to shallow root growth, making your plants susceptible to hard freezes and heat stress.
How do I calculate the precipitation rate?
The average precipitation rate is determined by the flow rate of your sprinklers and their spacing. To calculate the precipitation rate (in inches of water per hour) for either square or triangular spacing, use this formula:
precipitation rate= (g.p.m. of full circle sprinkler) multiplied by (96.25) divided by (the head spacing in feet) divided by (the row spacing in feet)
- g.p.m. of full circle sprinkler = flow rate (in gallons per minute) of an equivalent radius sprinkler that waters a full circle
- head spacing = the spacing between sprinklers in the same row
- row spacing = the spacing between each row of sprinklers
What does "precipitation rate" mean?
The precipitation rate is the depth of water distributed on the ground over a given period of time. A typical precipitation rate for pop-up spray sprinklers is two inches per hour, about equal to a hard rain.
How do I minimize run-off when I water?
Use multiple start times if the ground will not absorb water at the rate it is applied. This is usually necessary for pop-ups, which water at a fairly high precipitation rate. Program the controller to use three or four start times, and water for one third or one fourth of the total watering time at each start time. Heavy clay soils may need even more start times, sandy soil will need fewer start times.

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