Smart Irrigation: Controllers and Sensors
Over-irrigation or under-irrigation can increase the incidence of plant diseases, waste water and reduce overall landscape conditions. The efficiency of an irrigation system depends on several factors, including design, installation, and specific site conditions. Water applied to a landscape can account for a significant portion of a property’s water use. Due to improper watering methods, a great deal of water is lost to evaporation, wind and runoff. Reducing or eliminating this loss can reduce utility bills and create a more water-efficient, healthier landscape. Outdoor water savings can be achieved using smart irrigation technologies.
Smart irrigation controllers and sensors have been developed to reduce outdoor water use by irrigating based on plant water need compared to traditional automatic system timers, which irrigate on a user-determined fixed schedule. This technology exists as a complete controller or as a sensor that can be added to an existing irrigation timer to create a smart controller. Smart irrigation technology uses weather data or soil moisture data to determine the irrigation need of the landscape.
Smart irrigation technology includes:
These products maximize irrigation efficiency by reducing water waste, while maintaining plant health and quality. Incorporating smart irrigation technology in the landscape can potentially reduce outdoor water consumption. This technology is appropriate for small, residential landscapes as well as large, managed landscapes. The following sections describe how each product functions and the advantages and disadvantages of each product. Irrigation managers and homeowners should be aware that smart irrigation technology will need to be periodically adjusted and maintained for maximum water savings.
Smart Irrigation Technology: New Controllers
There is a broad spectrum of smart irrigation technology that consumers can benefit from utilizing. Choosing the correct technology for the situation is essential to achieve potential water savings. Watering restrictions exist in some areas of Oklahoma, so the irrigation timer may be adjusted for allowed watering days. Irrigation controllers can be separated into two main categories: Climate based controllers and soil moisture based controllers.
Climate-based controllers also referred to as evapotranspiration (ET) controllers use local weather data to adjust irrigation schedules. Evapotranspiration is the combination of evaporation from the soil surface and transpiration by plant materials. These climate-based controllers gather local weather information and make irrigation run-time adjustments so the landscape only receives the appropriate amount of water.
There are three basic types of ET controllers:
Signal-based controllers use meteorological data from a publicly available source and the ET value is calculated for a grass surface at the site. The ET data is then sent to the controller by a wireless connection.
Historic ET controllers use a pre-programmed water use curve, based on historic water use in different regions. The curve can be adjusted for temperature and solar radiation.
On-site weather measurement controllers use weather data collected on-site to calculate continuous ET measurements and water accordingly.