Improving water efficiency

Five tips to maximize the effectiveness of an irrigation system
Friday, March 2, 2012
By Anthony Kampen

In 2003, the City of Toronto introduced a Water Efficiency Plan (WEP), recognizing that projected population and employment growth would put increased demand on the water supply system. Rather than meeting the increased demand by expanding costly infrastructure, the City chose to build in system capacity by promoting water conservation among system users. The conservation strategy was outlined in the WEP and included public education, replacement programs for inefficient toilets and clothes washers, and outdoor water audits.

Outdoor water audits were aimed at reducing summer outdoor water use by changing practices and habits associated with the watering of residential lawns, sports fields and parks. The report identified that peak day water demand occurred during summer months and irrigation of the landscape contributed significantly to the peak demand.

Irrigation systems have become increasingly commonplace in the past 30 years. New buildings are rarely constructed without an in-ground sprinkler system to water the beautiful landscapes that are installed.

While this has been of great benefit to those who toil in the green industry, there are many aging systems that operate inefficiently much like the toilets and clothes washers the WEP identified as needing replacement. Advances in irrigation technology mean many of the inefficiencies can be reduced or eliminated.

Here are five tips to maximize the effectiveness of an existing irrigation system.

1. Audit the system
The first place to start when determining the state of an existing system is to have an audit performed by a certified landscape irrigation auditor. This in-depth analysis will evaluate system design, soil conditions, climactic factors, nozzling, system breaks and the existing landscape in order to develop a comprehensive set of recommendations that are specific to the conditions that exist at a property.

2. Replace old heads
As irrigation heads get older they don’t operate as efficiently as they did when new. Most people have seen instances where: irrigation heads will not stop rotating and end up watering the roadway; or the heads don’t rotate at all and remain fixed in one spot.

More often than not, the heads in question are old, worn out and need to be replaced. Keep in mind that irrigation heads have a lifespan of approximately eight to 10 years, so if the heads are approaching that age it may be advisable to change them before problems arise.

Another advantage of changing old heads is the opportunity to take advantage of advancements in head or nozzle technology. Older heads tend to deliver water in small droplets that are easily blown about by the slightest breeze, causing the water to fall in non-target areas. Modern heads project the water in droplets that are much larger and heavier, so they are more likely to land where they were intended.

3. Don’t ‘set and forget’
All too often, the irrigation schedule is set in spring when the system is opened up and then ignored for the rest of the season. Scheduling is not a “one-size-fits-all” proposition; rather, it requires ongoing monitoring to ensure the landscape is not being under-watered or, as is more often the case, over-watered. Through the course of the irrigation season, temperatures fluctuate and rainfall is unpredictable. With these uncertainties, irrigation scheduling must be tweaked continually to ensure the needs of plants are being met.

4. Install a master valve
Irrigation systems develop leaks. This is an unavoidable situation. Most times the leaks are quickly detected and necessary repairs can be made. However, sometimes leaks are not readily visible and it can take days or weeks before they are caught. If such a leak occurs in the main water supply line, a great deal of water can be lost because this line is continually pressurized. If there is an open outlet, the water will continue to flow.

To minimize this potential source of water loss, it is a good idea to install a master valve on the main line. The master valve is wired into the irrigation timer and only opens when a watering sequence is scheduled to run. In this case, a leak in the main line will still result in water loss during the time the system is running but water will not continue to flow 24 hours undetected.

5. Upgrade the brains of the system
The greatest advances in irrigation technology have been made at the controller. Gone are the days when scheduling options were limited to having the system come on daily or every second, fourth or seventh day. New controllers allow for unlimited flexibility in terms of when the system can be scheduled, how often, which zones, how long for each zone, how many times per day, and so on. Familiarity with site conditions is extremely important with this increased flexibility.

For example, an area that is shaded during the middle part of the day and sheltered from wind will require far less water than an area that is fully exposed to sun and wind during the hottest part of the day. These variations should be reflected in the watering schedule for each zone and modern controllers can easily accommodate this.

Smart irrigation controllers are currently the pinnacle of irrigation control technology. They can use either climactic data or data generated by soil moisture sensors to determine the right amount of water required for the landscape. Soil moisture sensors may be preferential to climactic data as climate information is often generated from a weather station that may be located many kilometres away and, therefore, may not accurately reflect the actual conditions on the property where micro-climates can greatly influence irrigation needs.

Moisture sensors, on the other hand, are measuring the amount of water available in the soil where the plant roots are located. These generate more accurate information on which an irrigation schedule can be based.

Another potential disadvantage of using climactic data is that a subscription to a weather service may be required. This involves an ongoing annual fee.

Further advantages of smart technology include the ability to monitor the irrigation system remotely through the Internet, the possibility of detecting leaks in the system when a smart controller is connected to a flow sensor and the opportunity to alter the system scheduling remotely.

A recent Canadian innovation has further enhanced the smart capabilities by introducing technology that allows the controller to communicate with the irrigation valves wirelessly, thereby eliminating the need for irrigation wire. This is an extremely attractive option for new installations. It is also a cost-effective solution for systems that suffer from electrical problems.

Anthony Kampen is vice-president of Boot’s Landscaping & Maintenance Ltd., in Richmond Hill, Ont.

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