By Bob Howley and Doug Smith, Irrigation Analysis, LLC
With the worsening drought, tightening water supplies, and increasing water demand, we are caught between a rock and a hard place when it comes to water and unfortunately, it does not look like this situation will get better any time soon.
According to the Colorado Water Conservation Board (CWCB) State Water Plan, our collective goal is to reduce municipal water use in the State by 400,000 acre-feet of water through conservation by 2050. Since landscape irrigation uses roughly 50% of the municipal water supply, it is critical that we conserve as much of our landscape irrigation water use as possible in order to achieve this goal.
Many irrigation systems are less than 50% efficient in delivering water to the plant material, or to phrase it another way, more than half of the water used for watering our landscapes is lost or wasted.
Water costs are rising with most water providers increasing their water rates by 5% or more per year. Beyond the water cost and budget impacts is preserving our shared water resources to sustain Colorado’s rivers and streams and the outdoor lifestyle that we all value.
The question is: can the landscape industry in Colorado help to achieve the water use reduction goal set by the CWCB and still have attractive, healthy landscapes?
It is important to understand and implement new technologies to upgrade and modernize irrigation systems with the intent to save water. Just like there are newer water conserving toilets and showerheads, there are more efficient spray nozzles, sprinkler heads, as well as rain and moisture sensors, and weather based, “Smart” Controllers that all can deliver water more efficiently to our landscapes.
High Efficiency Nozzles are a simple way to reduce water use. Multi-Stream Rotary nozzles can provide improved uniformity which in turn reduces the overall water use to an area. There are also newer fixed spray nozzles that can improve the Distribution Uniformity (DU) compared to older traditional nozzles.
Pressure regulation also plays a vital role in the DU by providing the optimum pressure for nozzle performance. Pressure regulating spray bodies, now required in Colorado per House Bill 19-1231, ensure that all the nozzles are operating at the same pressure.
Flow sensors are a useful tool that provide data on flow rates and water use of an irrigation system. They can also identify abnormal flows, and when used in conjunction with a master valve and a compatible controller, will shut the system down and potentially send alarms and alerts. This is an effective way to stop large amounts of water loss due to a pipe break or a broken head continually running during an irrigation cycle.
Weather based “Smart” Controllers are another great tool in saving water by adjusting run times or watering days based on daily weather patterns. There are many offerings and most operate on a similar principle although they must be understood by the system manager to deliver the savings that they can readily offer. There are some that require annual subscriptions and some that use local sensors or historical data. If properly programmed and managed on a system that is otherwise capable of operating efficiently, these can reduce water use throughout the season.
Web-based control takes the “Smart” Controller functionality a step further by allowing the water manager to access the controller remotely using any mobile device to review programming and make adjustments as needed, or to review any errors or alarms the controller may have generated. It can also provide alerts from the flow sensor in the event of a leak.
What else should be considered to save water?
Improved Maintenance and Management to repair leaks in a timely manner. “Smart” Controllers with flow sensors can help identify these when they occur.
Perform regular and complete system checks to make sure everything is working well. Actively manage the irrigation run times and watering days to not overwater beyond what the plant material requires.
Turf Conversion – we need to have and appreciate landscapes that are more water efficient and should reconsider wall to wall, high-water use bluegrass in our semi-arid environment. Consider planting lower water use shrubs and native grasses especially in more peripheral landscape areas.
An Irrigation Efficiency Audit/Evaluation performed by an Irrigation Association certified, (CLIA), or Qualified Water Efficient Landscaper certified (QWEL), can provide insight to where the most practical water savings can be achieved. The audit should be in depth and look at system function, performance, and programming, and provide a detailed and actionable report about the system and how to save water.
The use of high efficiency products and better technology are a great way to help reduce water use in the landscape. However, it is dependent on the landscape manager to ensure that the system is operating at its peak efficiency. We all need to continue to work together to champion the cause of reducing landscape water use, and using water conserving irrigation technologies gives us a better chance to reach those goals.
Bob Howey, Doug Smith, and Irrigation Analysis, LLC are a Colorado-based team of independent Irrigation Association and QWEL certified irrigation efficiency and water saving experts that performs Irrigation System Evaluations/Audits, Water Use Management, Water Efficient Irrigation Design, irrigation problem solving, and other related services. Our goal is to save water by supporting larger properties and their landscapers in efficient water use.
