We have a water problem. Too often sprinkler controllers are set and forgotten; not adjusted when the weather changes. A lot of water is beng wasted.
When the EPA says landscapes are often watered with twice the needed water, people don't believe it. Plus they fear that cutting back on water use will hurt their landsacape. I have seen just the opposite. When landscapes are watered right they are healthier. You can have efficient water use and a healthy landscape. The secret is knowing when to water, and when not too.
Water meters are installed at most properties to enable water departments to bill you for the water you use. Some water utilities may only read meters 6 times a year and send out bills every two months. Customers discover weeks later how much water they used.
A flow sensor is similar to a water meter; it measures the flow of water going through the pipe and feeds the flow rate into electronic control equipment. With a flow sensor connected to irrigation control devices water managers can track water use in real-time; not having to wait to get the water bill.
It seems like over the last few years everyone has been talking about drought and different ways to conserve water. As a homeowner, one of your larger uses of water is on your landscape. Getting a sprinkler timer was a great start to taking control of your outdoor water consumption. But when you get a sprinkler timer, all you are doing is creating a water schedule. A specified time of the day, the numbers of days per week that you permit your sprinklers to release much needed moisture into the soil. It may be that your city puts day of the week restrictions on you, or maybe you are scheduling based upon gallons of water used. Either way, what happens when your timer decides it’s time to turn the sprinklers on and it’s raining?
This is the last tuna can article. I hope these have helped you visualize that your sprinkler system applies water in measurable amounts of water. And the more water you apply, the deeper it will soak into the ground. Using tuna cans is a good way to measure sprinkler system performance but there are advanced techniques to get this job done.
What have we learned so far? In the last blog I wrote about improving watering uniformity. Don’t expect a smart control system to fix a bad sprinkler system. Tuna Can Lesson 2 reminded us that sprinklers apply water at different rates. Valve run-time is based on how much water needs to be applied and how fast the sprinklers apply water. I remember the very first time I setup a computer controlled irrigation system. After a week the customer called and said, “Take it back”. I said, “What’s wrong?” He said, “The grass is dying and the shrubs are drowning.” We checked it out. The wiring was wrong. The shrub bubblers were watering for over an hour and the big lawn sprinklers were watering for only 10 minutes. Once we fixed it, the system ran great.
Years ago, as a landscape contractor, I met with the irrigation Foreman at a job site. There was a spot in the yard with dying grass. I told him it looked like the sprinklers were not getting the area wet. He told me to stand in the dry spot, he would turn the sprinklers on to see if I got wet. Not the best science and a poor excuse for a problem with the sprinklers. As you can imagine, water was shooting over the dry spot and not landing in the area with dead grass. I should have brought my tuna cans to show him the problem.
When you do your tuna can test you will be surprised to see the difference in the amount of water in the tuna cans when the test is over. No, sprinklers are not perfect; they do distribute water with perfect evenness or uniformity. Good sprinklers, with the right nozzle, properly positioned will get close, but never perfect.
There is good science and math to help you quantify distribution uniformity, but I am not going to get into that here. When you run a tuna can test you will see which cans do not have as much water and those that may be over flowing. At the risk of pointing out the obvious, those areas with too much water are being over watered; so water is being wasted. But the grass probably does not look very good in the areas where tuna cans had very little water. So what do you do about it?