Effective irrigation systems, technology and practice provide a major contribution to water conservation, Peter Longman, Northen Europe Landscape Area Manager, Rain Bird Europe tells us more.
We sometimes take the availability of water for granted. Yet the heatwave of summer 2018, with its threat of hose pipe bans, reminds us not to be complacent. We need to take measures to combat the fact that water is not the abundant resource it would appear to be. Around 97% of all the earth’s water is saltwater, 2% is held in snow and icebergs and only 1% is freshwater – the only portion currently usable for human consumption. This freshwater is continually recycled as it evaporates and returns to the earth in the form of rain, snow and ice. But most of this “fallen” water evaporates immediately, pours into inaccessible areas or flows away before it can be retrieved. Only about 10% of total rainfall on earth is retrievable for use by humans and of that only 40% (or 4% of total rainfall) is ultimately used.
So the problem could be addressed by re-using water more effectively, improving water delivery systems to prevent wastage and more desalination. However, as over two thirds of the freshwater usage is used in agricultural applications around the world, the conservation of water through efficient irrigation needs serious focus as it is an approach that can be implemented immediately.
A vast range of irrigation systems and solutions are available from pressurised sprinklers to sophisticated computer controls using satellite data, the internet and The Cloud. Sprinklers dominate agricultural and landscaping use, from small pop-up spray head sprinklers to large rotating versions for commercial or agricultural applications. Low volume irrigation technology, such as drip emitters (Dripline), is rapidly gaining popularity as it eliminates waste by delivering precise amounts of water slowly and evenly, at or near the plant’s roots.
The amount of water used to maintain the quality of golf course greens is often a target of criticism, yet it is this sector that has been at the forefront of implementing water-saving measures, including the use of advanced central control systems and reclaimed water.
A major element of the water used in landscaping is used to irrigate grass which in general needs more water than other types of plants. Over-watering can be common but there are simple practices that will reduce their water consumption and costs whilst improving the health of the landscape. A simple practice is to water large landscape sites at the ideal time of day – between 5am and 10am – since early morning watering is most efficient.
There are key steps to implementing water-efficient irrigation, starting with proper irrigation design and finishing with planned maintenance regimes. Whatever the application, different plants require different amounts of water. Once this has been recognised, it is important to divide landscapes into zones to accommodate the watering needs of different plants or turfed areas. Also, factors such as the variation of exposure to the sun will affect irrigation needs.
When planning, consultation with a certified landscape or irrigation professional and/or landscape architects is recommended – they are trained in irrigation design and are knowledgeable about water-efficient products, the watering needs of various plants and local environmental conditions.
Automated Irrigation Systems
There can be a perception that automated irrigation systems use too much water, but this is not the case. They can be set to use the minimum amount necessary to maintain the health of the plant or agricultural crop. With central control systems and management over the internet, automatic controllers can be used to implement water-conserving regimes. These can feature multiple start times and independent programs which allow for shorter and more precise run times.
Indeed, controllers provide an easy way for users to adjust their irrigation system based on the needs of the environment. During the rainy season, a user can adjust the controller’s “water budget” down to 15% of its peak setting to reduce water usage by 85%. A rain delay feature will allow a user to postpone watering when it is wet and irrigation is not needed whilst a cycle and soak capability applies water at a rate that the soil can more easily absorb, reducing run off and waste.
The controller can also calculate daily evapotranspiration values and automatically adjust station run times to replace only the water needed by the plants. By also adding an automatic shut-off device to controllers, such as a rain or moisture sensor, some 15-20% more water savings can be made. Sensors are available for both residential and commercial applications.
Automated systems make it easier to design irrigation schedules according to the needs of each irrigation zone. For example, a typical golf course could have a wide range of microclimates – from fairways, greens, rough and surrounding areas, to the clubhouse areas. A golf central control system makes it possible for golf course managers to apply the precise amount of water needed for each zone.
In landscaping, water can be wasted through evaporation when systems appear to be “misting or fogging.” This is generally a result of excessively high water pressure and can be reduced by using pressure regulating high efficiency nozzles, sprayheads, valves and regulators.
Maintaining Your Irrigation System
Once a system has been properly designed, proper installation and maintenance are essential. Employing a fully qualified irrigation contractor is recommended for the entire process. On going maintenance programmes, whether conducted by third party professionals or by qualified in-house maintenance managers, are essential for continuous water conservation. Periodic monitoring is just as important, since broken pipelines, clogged sprinklers and the like can all defeat the best efforts to achieve water savings. There should be routine inspections of the irrigation system and adjustments to watering schedules as the seasons and weather change or indeed when plants are changed.
Those engaged in the manufacturing, distribution and use of irrigation systems are committed to water conservation practices and the intelligent use of water. They are working to be part of the solution by developing and adopting smart irrigation solutions and landscaping techniques that conserve water. There is no doubt that water-efficient irrigation offers good payback and will have a significant impact on global water savings.