CREJ - Property Management Quarterly - April 2017
"The efficiency of an irrigation system is dictated by many factors, including human, mechanical and environmental components,” according to WaterSense, a U.S. Environmental Protection Agency partnership program. “Implementing mechanisms and practices that increase an irrigation system’s efficiency could save a property more than half of its outdoor water use. Eliminating waste requires trained professionals, appropriate irrigation schedules and efficient technologies.” In Colorado, and other arid Western states, it is generally accepted that 50 percent of municipal water use is attributable to landscape irrigation. • The case for conservation. Irrigation waste carries a high price. Municipal water used for irrigation can range in price from $5 per 1,000 gallons to potentially $15 per 1,000 gallons along the Front Range, depending on water purveyor and specific rate structures. Irrigation excess often accounts for 20 to 40 percent or more of landscape water requirements. As an example, consider a Front Range landscape where the seasonal water requirement (water budget) is 10 million gallons. This would be a typical seasonal budget for a site with approximately 550,000 to 600,000 square feet of irrigated landscape. In this example, 25 percent excess (waste) will come at a cost of more than $17,000 annually for this site when the billable rate is $7 per 1,000 gallons. Additional costs, not as easily measured, are those associated with excess water accumulation on nonpermeable surfaces. Runoff, puddling and water collection on asphalt and other impervious surfaces shortens the life expectancy of these surfaces. Increased irrigation efficiency will reduce water collection on surfaces where water adds no value and, typically, does harm. Efficient irrigation and proper management also contribute to more predictable and, therefore, more manageable water and irrigation service-related expenses. Budget overruns and expensive surprises can greatly be reduced, if not eliminated. Additionally, plant health and visual appeal improve when plants receive the correct amount of water, at the correct time. And let’s not forget social responsibility. We all owe some responsibility for conservation and resource stewardship. Achieving Irrigation Efficiency Proper management is a critical component to achieving water conservation objectives. With the accelerated rate of new technology introduction, management plays an even more important role in achieving desired results. Irrigation management is more than just repairs; it includes responsibility and accountability for a water budget derived from a given landscape’s seasonal water requirement. An effective management plan is comprised of many parts. • Irrigation assessment (audit). Begin with the end in mind. An irrigation assessment becomes the road map that outlines the actions and initiatives that should be undertaken to improve the performance and overall efficiency of an irrigation system. The assessment will produce the information needed to calculate the landscape water requirement (water budget) for the property. In many instances, a seasonal landscape water budget may already exist. The assessment also should prioritize efficiency improvements based on payback opportunity. Irrigation system improvements/upgrades do not all deliver the same return on investment. Additionally, the assessment can be an initiative that produces a map, typically plotted on a satellite image, showing locations of key irrigation system components and potentially other assets. A map becomes a very useful tool at a time of management and/or service provider change. • Implementation. The irrigation assessment, in and of itself, produces no water savings or efficiency gains. All too often, we see examples of audits and assessments completed with no action taken on any recommendations. Given the costs associated with water waste and inefficiency, irrigation audits and assessments should be given serious review. There almost always are opportunities for phased in improvements. Realized savings from initial phase improvements may become the revenue source to fund additional improvements. • Scheduling (weather-based irrigation controllers).Proper irrigation scheduling is the single-largest contributor to the reduction of water waste in the landscape. Watering schedules must be adjusted frequently in response to changing weather conditions and changes in any given plant’s water requirement to reduce waste. Combined with proper management, weather-based irrigation controllers become the most effective tool for reducing water waste and improving plant health and visual appeal. Most weather-based controllers combine horticulture science and real-time weather data to automate the process of calculating and adjusting irrigation schedules. It’s a process of taking guesswork out of irrigation scheduling and putting sound science to work. Remote management typically can be enabled via connected devices to deliver even greater flexibility and efficiency. • Maintenance. Once an irrigation system is operating in an efficient manner, ongoing maintenance is the key to keeping the system operating at peak performance. Frequent inspection of all components in operation is the cornerstone of effective maintenance. Line leaks, sprinkler-head failures and other water-wasting conditions should be discovered quickly and corrected in a timely and cost-effective manner. In those situations, where conventional controllers are still in use, frequent site visits are necessary to keep controller schedules properly adjusted. • Sustainable results. Efficient technologies, coupled with sound irrigation management practices, can produce 20, 30 or 40 percent reduction in landscape water use on many sites. “It is evident that an ET, weather based controller, with proper management, can have a great impact on applied irrigation throughout the growing season,” according to a conservation manager from the two-year 2015/2016 Aurora ET Controller Pilot Study. “While the addition of higher-efficiency heads and nozzles give an additional benefit, it has much lower impact than sound water management practices.” ET, or evapotranspiration, is the sum of the water used by a plant (transpiration) and water lost due to evaporation, so the ET value is the amount of water that needs to be replaced to sustain healthy and visually acceptable plant material. This science is used to determine irrigation schedules. Over the last eight years, Denver Water has made significant progress through its “Use only what you need” campaign. Now, Denver Water is customizing water budgets based on irrigated area for its largest commercial customers. Water budgets allow both Denver Water and its customers to know exactly “what they need,” according to the Colorado Water Plan, published December 2015.