Adding an automatic irrigation controller
The busy folks at the American Water Works Association found that installing an automatic controller on a manual system increases water use by 47 percent. This statistic seems to indict controllers as being very nonsustainable. But when properly used, controllers really can save lots of water.
Don't assume you need a controller. It isn't a requisite component of a good irrigation system, and there's no shame in having a manually operated system that you turn on and off yourself. Still, if you have heavy soils or a large property, or you're disabled, busy, or just lazy, a controller may be the solution.
Advantages and disadvantages of an automatic system
Here are some benefits of using automated irrigation controllers:
- You can cycle the controller to prevent runoff in tight soils and on slopes. For instance, you can set it to water for 5 minutes at a time, repeating the cycle every hour so the water has a chance to soak in.
- Most controllers are easy to operate. Smart controllers (which I cover later in this chapter) are a little more difficult to program, but you only have to set them up once.
- You get exact control of your watering program and don't have to depend on your memory or walk around with a stopwatch.
- A controller works even when you aren't there.
- Standard controllers require adjustment only for seasonal changes and extreme weather conditions. Smart controllers don't have to be adjusted at all.
The following are some drawbacks of using automated irrigation controllers:
- They aren't totally automatic. Unless you have a smart controller (see the next section), making them work efficiently is up to you.
- They have to be programmed carefully. If they're programmed to overwater, for example, they continue to do so for as long as you pay your water and electric bills.
- You have to make seasonal adjustments to the program to get sustainable results.
Smart versus dumb controllers — and why it matters
A traditional controller is just a timer. For example, you set it to turn on valves 1, 3, and 7 for 20 minutes each at 6 a.m. on Tuesdays and Fridays. The controller does this until you tell it differently, because it's ignorant of outside conditions. Unfortunately, conditions change constantly. And when you think about it, time has nothing to do with water need. The conditions that regulate water demand — temperature, wind, cloud cover, humidity, precipitation, and of course, the seasons — are in a constant state of flux.
Smart controllers are different. They're keyed in to actual conditions, getting data from local weather stations and translating that data into an ever-changing program that's sent to your controller by satellite. (Some smart controllers come with their own weather station that lives right in your backyard; others use "historical" weather data for your area, which isn't nearly as accurate as real-time information.)
- V ^ A system with a smart controller, which some people call "watering from y^JL outer space," works really well and can reduce your water use by 20 to 50
- 101 1 percent or more. Smart controllers cost more than conventional ones, but you recoup that cost quickly in water savings.
To use a smart controller, you program it one time (when you install it), fine-tune it a bit during the first few weeks, and then never touch it again. The controller asks you for soil type, kinds of plants, slope, exposure (sun or shade, for example), and other facts about the environmental conditions in each zone. It uses this information to modify the incoming schedule for each zone.
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