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Technologies - Irrigation, Rainwater Harvesting, Gray Water Reuse and Artificial Turf

In Arizona, up to 70% of residential water is used on the landscape. Water used to irrigate landscapes is often wasted due to inefficient irrigation systems. Significant water use reductions can be achieved through the use of new and emerging irrigation technologies.


IRRIGATION EQUIPMENT
Master Valve with Electronic Flow Sensor
An irrigation master valve is typically installed at the point of connection to the water source. The master valve opens whenever any station is watering and closes when no station valves are on. A flow sensor installed just after the master valve detects leaks based on the programmed parameters. When used with a controller that can read a flow sensor, the controller will shut down a station valve when a leak is detected, and then move on to the next station in the program sequence. If connected to a central control system it will send a message back to the central computer about the problem and its location. Although not commonly used in the residential setting, they would provide a safety net for home irrigation systems, preventing uncontained or unnoticed leaks from flowing continuously until discovered.
Lawn Sprinklers
Sprinkler heads are nozzles or devices, which may or may not rotate, that distribute water under pressure through the air. Sprinklers that spray (often called "spray heads), do not rotate. They apply water over a circular area in a fan-shaped stream. They have a high application rate, meaning that they they discharge a large volume of water in a relatively short amount of time (at an average rate of 1.4 inches per hour), which can lead to increased evaporation and to run-off. By contrast, rotor sprinkler heads emit a single or multi stream of water that rotates back and forth in a circular pattern. Rotor heads have a lower application rate (at an average rate of .7 inches per hour) and apply water more uniformly than spray heads. When located on a slope, a sprinkler head in the lowest places sometimes continue to flow for a few minutes after the sprinkler turns off. This phenomenon is called "low head drainage" and can be prevented by installing anti-drain check valves.
Bubbler Irrigation
Bubbler heads are typically used in planters, tree wells, or specialized landscape applications where deep localized watering is preferable. Water from the bubbler head comes through small orifices and either runs down from the emission device or spreads a few inches in an umbrella pattern. Bubbler emission devices are equipped with single or multiple port outlets.
Drip Irrigation
Irrigation Equipment, Photo Drip irrigation is a system of valves, tubing and emitters that allows water to drip slowly at the root zone of each plant. These systems are efficient because they water only the root zone and eliminate run-off, water waste, and excessive evaporation. Various sizes of emitters, including multi outlet emission devices, allow for the application of different gallons per hour in order to match a plant's water requirements. Emitter size can be increased as a plant grows or plugged if a plant dies or no longer needs supplemental irrigation.
Smart Controllers (Timers)
Irrigation Equipment, PhotoIrrigation controllers or timers are programmed to turn an irrigation system on and off based on a preset schedule. Recent advances in controllers have made them even more efficient. "Smart" controllers sometimes called evapotranspiration (ET)- based controllers, automatically adjust the watering schedule according to weather-based information, such as temperature and humidity. (ET is the amount of water lost from the soil through evaporation plus the plant's water loss, both of which are dramatically affected by weather conditions.) This information may be either pre-programmed into the controller based on historic data, or adjusted daily based on a signal from a local weather station or satellite. Smart controllers can reduce irrigation water use by 20-40%. Some controllers have sensors (shut-off devices) attached so that watering is temporarily stopped due to rain, wind, high soil moisture, or freezing temperatures.
Rain Sensor
Rain sensors are designed to stop irrigation in response to a specific amount of rainfall, such as 1/8 to 1 inch. When the sensors dry out (in a day or two), they turn the power to the valves back on. Rain sensors are mounted outside in an open area and are easy to install. They are available in both wireless and hard-wired versions and are connected to the shutoff valve on the common line of the automatic watering system. Some states and several cities mandate the use of a rain sensor in all new sprinkler systems.
Soil Moisture Sensor
Irrigation Equipment, PhotoSoil moisture sensors measure the level of moisture in the soil and are frequently used in agriculture, on golf courses and in lawns. They are sometimes used in planting beds that have drip irrigation, however, more sensors are needed if plants have differing water needs and root depths. Soil moisture sensors stop irrigation if the soil is wet and resume irrigation when the soil is dry. A good system allows you to set the moisture level at which you want to stop and start irrigation. There are a variety of soil moisture sensor systems on the market at different price levels.
Wind Sensor
Wind sensors turn off irrigation valves when the wind reaches a preset speed, e.g. 12 – 35 mph. These are more commonly used with automatic sprinkler systems to reduce evaporation and prevent the wind from blowing the spray away from the targeted areas.
Freeze Sensor
Freeze sensors automatically turn off irrigation valves when the temperature drops to a pre-set level, e.g., close to freezing. These are typically used in regions where irrigation systems are not decommissioned for the winter, yet still have a chance of frost.
Combination Sensor

Irrigation Equipment, Photo

Sensors are sometimes combined into one unit to eliminate the need for separate sensors and installations. A combination unit that includes wind, rain, and freeze sensors is sometimes called a mini weather station or complete weather station. The sensors automatically shut off the irrigation system if there is too much rain or wind, or if it is too cold to irrigate, and then resets the system when conditions are favorable.

Irrigation Sub-Meters Installing a meter or sub-meter dedicated to measuring outdoor water usage can reduce sewer fees. Sub-meters quantify the amount of water used for landscaping and therefore not returned to the sewer.
RAINWATER and GRAY WATER HARVESTING SYSTEMS
Rainwater Harvesting

Rainwater Harvesting, PhotoA rainwater harvesting system is appropriate for large-scale landscapes such as parks, schools, commercial sites, parking lots and apartment complexes, as well as small-scale residential landscapes. Simple rainwater harvesting systems include gutters, downspouts and yard contouring to direct rainfall to plants. More complex systems store rainfall in rain barrels or cisterns, some equipped with filters and pumps.

Harvesting Rainwater for Landscape Use Acrobat Icon PDFs (5 MB)

University of Arizona Online Rainwater Harvesting CourseOffSite Icon focuses on using rainwater for landscaping around Arizona.

Gray Water Systems Graywater Harvesting, Photo: Hank M.

Gray water, the wastewater generated from domestic processes such as laundry and bathing (not from kitchen sinks or toilets), comprises 50-80% of residential wastewater water. Gray water systems typically direct gray water for irrigation use.  Some communities require gray water systems in new construction, and rebates are sometimes available for installing a gray water system as a retrofit.  All residential systems must follow the ADEQ guidelines.  ADEQ Gray water brochure Acrobat Icon PDFs (288 KB)

ARTIFICIAL TURF

artificial turfArtificial turf is an alternative to grass that uses little water and is low maintenance. Some communities around Arizona use artificial turf areas for landscaping and recreational purposes. Artificial turf requires the use of water for dust control and for cooing, as temperatures may rise as high as 120 degrees or more. However, the amount of water is small compared to the water required to irrigate natural grass.