Turfgrass is the target of many advocates for saving water. For example, a new law in Nevada prohibits the use of water for irrigation on all nonfunctional grass by 2027. The Southern Nevada Water Authority is paying residents $3 per square foot to remove grass. Other states are following the example, all intending to reduce water use to reduce the impact of the drought. This approach will not bring about the desired result. Rebates for turf removal will save water, but more is needed to make the difference they need to solve the problem.
Agriculture uses approximately 80 percent of the Colorado River's water. According to Dennis Pittenger, the University of California Cooperative Extension, landscape water use amounts to only 9 percent of the developed water use in California. If we cut the water to zero, we would only save 9 percent. Lawns have been singled out as a water waster but only consume 3.5 to 5 percent of annual statewide water use. This situation is not exclusive to California. Similar situations exist for all the Colorado River water states.
Turfgrass is expensive to remove. The rebates alone can add up to well over $125,000 an acre for removal. The grass is replaced with another plant type that also requires water. Often, this plant is watered with an inefficient irrigation system, and water waste continues. When it was determined that cars waste too much gas, the solution was not to ban cars. The answer was to use technology to improve mile-per-gallon standards. Many less expensive and less restrictive ways to reduce landscape water use exist. Changing how we water instead of what we water can make a significant difference.
How you water
The first step toward responsible landscape water use is eliminating traditional spray head irrigation. Conventional spray heads deliver only about 50 percent of the water they emit to your plants or turf. This means 50 percent is wasted. Most of the waste occurs from evaporation and wind drift. You can achieve better results by switching to some of the new rotating nozzles or microspray nozzles available today, along with reducing the pressure of your system. This is an excellent first step in the process.
Switching to drip irrigation allows for precise water delivery to the plant's root zone, avoiding water loss from evaporation, wind drift or runoff. Drip irrigation also helps landscapes look better. Because water is not sprayed on the plants, there are reduced fungal diseases. Drip irrigation works very well in color beds and shrub beds. Drip irrigation and drip mats are being used increasingly in turf applications. Drip irrigation in turf is more expensive than installing sprays, but the water saving accumulates over the years—the savings more than make up for the extra expense at installation.
Replace that conventional controller
A traditional irrigation controller runs a fixed schedule despite the difference in weather day to day. You must set that fixed schedule to accommodate the hotter days of the season, so there is no escaping that on the cooler days, it is applying more water than necessary. The only way to adjust these controllers is to touch them physically. This reduces the number of adjustments made, and often conventional controllers are changed just four times a year. As a result, large amounts of water are wasted.
A smart controller adjusts daily based on the weather. How much you can save with this step depends on the season and your local weather variability, but it typically is about 25 percent. This is a similar estimate for savings due to turf replacements. A smart controller is less expensive than a turf replacement and helps you save water over your entire landscape, not just the turf zones. If you want to reduce water use in landscapes, switching to a smart controller is the best first step.
What to look for in a smart controller
The best smart controllers adjust daily based on real-time evapotranspiration. Some models will adjust based on historical evapotranspiration. This means the adjustment happens based on what the weather was like in the past. This is better than a conventional controller but will not provide the same savings as a controller adjusting daily based on the daily real-time evapotranspiration.
Check to see how the smart controller uses rainfall information. Predictive analytics are only found in the smartest controller. Consider it a smart controller with a Ph.D., if you will. Here, we apply predictive analytics to add forecast weather to the mix. We go from reactive adjustments—responding to today's weather—to proactive adjustments, incorporating tomorrow's weather into today's schedule. With predictive analytics, water is reduced today if rain is coming tomorrow. Why fill up the soil with water today if it will rain tomorrow? The Ph.D. part of this proprietary technology is that it learns the difference between what is predicted and what happens over time, so it gets better than the forecast itself.
Don’t forget maintenance
A sprinkler head that points at the street rather than the lawn won't keep that lawn healthy, no matter how much water it sprays. A broken drip line becomes a fountain rather than a drip and can wash away all your savings. Even worse, repeated water runoff on hardscapes (sidewalks, pathways, driveways, parking lots, etc.) can erode those, too. This can lead to you losing the investment you made in your landscape and incurring additional repairs for your hardscape—a cost not often considered in landscaping. Monthly wet checks of your system are required.
As the price of water continues to increase, the money you save increases with the amount of water cost. Making changes to how you water instead of what you water will make the most significant difference in the shortest period with the least amount of investment. It's not often that you can get more paying less and put money in your pocket in the form of savings.