For Eco-Tip 12-9-18
Are You As Smart As Your Irrigation Controller?
By David Goldstein, VCPWA, IWMD
For over a decade, local water agencies have offered discounts on “smart irrigation controllers.” I lost my irrigation system in the Thomas Fire and recently replaced the controller with one fully subsidized through Ventura Water.
Smart controllers either sense the weather at your location or use internet transmitted weather information from sensing stations near you. With this data, they can adjust the irrigation schedule you program into them. Some sprinkler systems are programmed with historical rainfall data and sensitive to the particular types of landscapes that each part of your system will water. For a monthly fee, you can even get automatic sprinkler controllers linked to a satellite with weather data for Ventura County.
Recent rains provide an opportunity to test whether they are working properly. Next time rain is predicted, re-set your watering start time to a time you will be home, and check to see whether the system runs. If it does, the first place to look for a problem is in your program set up.
The new smart controllers are “smart” because they can sense rain. However, they only sense rain and act upon that information if you program them correctly. If you have trouble with the user interface, contact the manufacturer or consult their web site.
You also need to be smart in your usage of smart irrigation controllers by pairing the “brains” of the system with the correct tools for watering. Local water purveyors offer sprinkler head nozzles, but not all nozzles are correct for every application.
For low plants, use a low-emitting spray head. The higher the spray, the more likely wind will redirect water. If you need a longer “throw”- the distance water will travel from the sprinkler head – consider an MP Rotator. The “MP” stands for “matched precipitation.” An MP sprinkler head rotates a spray from one side to the other, slowly watering with large droplets. The MP Rotator provides a 30% water savings over conventional spray-head sprinklers. To save even more, use bubblers instead of sprinklers for trees and use drip lines for raised beds.
Another key to optimal use of your controller is to choose good times for watering. Water just before sunrise to reduce wind and allow water to soak into the soil before evaporation from the sun. Sunrise is better than night because, if water sits too long on the stems or root crowns of plants, many are vulnerable to fungus.
Lynda Crawford, of Waterwise Consulting, which assists local water agencies with conservation programs, recommends multiple short cycles for many gardens. “The first watering doesn’t soak in as well. It stays on the surface. If you water lightly at 6 AM and then again at 7 AM, the first watering will break the soil’s surface tension, and the second will sink in.”
The most basic technological “fix” for older smart systems involves the power supply. Older smart systems have a battery backup instead of storing irrigation programs on the web. If the battery dies and you do not manually re-set your controller after a power outage, your sprinklers will default to the factory settings, watering 10 minutes per day every day, even when it’s raining.
The wettest months in Ventura County are January, February, and March. When sprinklers run in the rain, they don’t just waste water; they also waste the energy it takes to pump water from reservoirs or the Sacramento Delta to our lawns.