Irrigation Technology
Posted on Dec. 12, 2023 / Irrigation / Subscribe 0
By: Sean Harrington and Lorna Heller
Irrigation technology has evolved over the years to be more efficient and environmentally sustainable. New technologies include weather-based irrigation controllers, efficient spray nozzles and rain collection systems. Upgrading older irrigation systems with these pieces of equipment can help save and evenly distribute water. Even with these new technologies, it is best practice to conduct irrigation audits to ensure the equipment is operating as intended.
Weather Based Irrigation Controllers
Weather Based Irrigation Controllers are recommended by the EPA due to their water savings ability. These devices work by communicating via Wi-Fi with local weather stations to get data that is used to turn on sprinklers when needed instead of always following a timer. This prevents sprinklers from turning on while it’s raining outside for example. These controllers account for temperature, humidity, rainfall, and other information resulting in more efficient water usage and healthier plants.
Efficient Spray Nozzles
Several types of sprinkler nozzles are used in irrigation systems. Spray-type nozzles are popular and found in many irrigation systems today. Because the spray nozzles distribute the water in tiny droplets, there is more surface area that is exposed to the environment. This can lead to higher evaporation rates and wind can carry the water away from the target landscape. This is often seen on sidewalks near turf grass where water is running onto the cement. Other sprinkler nozzles utilize multiple streams that rotate to evenly distribute the water to the landscape. This style nozzle has thicker streams that will lose less water to evaporation and wind. This will also increase distribution uniformity which is a metric of how evenly the water is distributed to the target landscape. Figures 1 and 2 show the difference between spray and rotary multi-stream nozzles.
Figure 1. Spray Style Sprinkler Nozzle.
Figure 2. Rotary Multi-Stream Style Sprinkler Nozzle.
Rain Collection Systems
Rain is water that we don’t have to pay for, so it can be a great way to reduce the amount of potable water used for irrigation. A common technique for collecting rainwater is to connect a rain barrel or tote to the downspout of a roof gutter. When it rains, the water on your roof drains to the gutter and then goes into the rain barrel. Rain barrels have spigots near the bottom that can be used to fill watering buckets or attach a hose for watering nearby plants or grass. For larger homes or businesses with a larger roof, you can link multiple barrels together with a siphon or use a larger tote. Rain barrels are usually 45 – 55 gallons while larger collection totes can range from 100 – 2,000 gallons.
Irrigation Audits
While all of these technologies can have multiple benefits to your irrigation system, parts and components can break or malfunction and need to be maintained. Irrigation audits are a great way to ensure that the irrigation system is operating correctly. It is best practice to have a landscape professional assist with the irrigation audit. Audits can vary in scope and detail, but some basics include checking for; leaks, overspray or runoff, distribution uniformity, rain shutoff ability, controller, clean sprinkler heads, seasonal watering schedules, and system operating pressure. Visit the EPA Water Sense website for more information on best practices for irrigation audits.
Summary
Irrigation technology has improved and allows for more efficient watering of landscapes. Upgrading systems can often lead to a favorable return on investment with rising utility costs and conserve a precious resource. To learn more about these technologies, visit the EPA Water Sense website.
The Honolulu Board of Water Supply also offers rebates on certain technologies discussed in this article. For more information, check out the Water Sensible webpage.
Sean Harrington is a project engineer working on the Honolulu Board of Water Supply’s Water Sensible program. He has a background in water engineering and works to quantify water savings for water-efficient technologies. He also networks with various vendors and distributors to discuss existing and future water conservation measure rebates.
Lorna Heller is a Civil Engineer with the Honolulu Board of Water Supply's Water Resources Division, Water Conservation Branch where she helps administer the various programs to institute sustainable water use behaviors and practices across the island of Oahu.
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