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    Landscape Watering Systems looks at how effective irrigation systems

    Landscape Watering Systems (LWS) of Dinton near Salisbury specialises in the supply of high quality irrigation products and offers high levels of sales and technical support. The company has developed relationships with many of the biggest names in the UK and global irrigation markets and has an extensive network of professional and experienced Installers.

    It’s director Simon Edginton looks at the latest developments in irrigation technology and practice:

    We tend to take the availability of water for granted, yet with all the attention given to climate change, we should not be complacent. Measures need to be taken to combat the fact that water is not the abundant resource it would appear to be.

    The Problem

    The world’s population growing by about 80 million people per year, equating to a freshwater demand of 64 billion cubic metres a year, so it is clear this is not just some local or short term issue. To put the problem into sharper focus, some 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. Whilst this freshwater is continually recycled as it evaporates and returns to the earth in the form of rain, snow and ice, 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 just 4% of total rainfall) is ultimately used.

    So the problem needs to be and is being addressed by using water more effectively. This means more recycling, improving water delivery systems to prevent wastage and introducing more desalination plants. These represent longer term solutions, but for the immediate conservation of water, employing efficient irrigation practices and systems provide the best solution.

    Irrigation Solutions 

    A vast range of commercial and residential  irrigation technologies are readily 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. New, low volume irrigation technology, such as drip emitters (Dripline), is gaining popularity as it eliminates waste by delivering precise amounts of water slowly and evenly, at or near the plant’s roots. This can be used in combination with advanced controls that adjust watering schedules according to weather conditions and plant needs. The golf industry has led the way in developing solutions and practices that have been adopted by other sectors.

    Effective Solutions

    A major element of the water used in landscaping is used to irrigate grass which generally needs more water than other types of plants. Over-watering is common but there are simple practices, such as adjusting a sprinkler timer to water for shorter periods during the cooler months, that will reduce water consumption and costs whilst improving the health of the landscape. Another simple practice is to water large landscape sites at the ideal time of day – between 5 a.m. and 10 a.m – since early morning watering is most efficient because the effects of evaporation due to wind and sun tends to be less at this time than during the warmth of the day.

    Planning for effective irrigation

    However, simple good practice is just one element and there are several key steps to implementing water-efficient irrigation and achieving maximum water savings. It starts with proper planning for irrigation design and finishes with regular planned maintenance regimes.

    Whether the application is a large commercial property, a golf course or a garden, different plants require different amounts of water. Generally, grass areas require more water to stay healthy than the shrubs and trees. Once this has been identified, 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.

    At the planning stage, consultation with a certified landscape or irrigation professional or/and 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

    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.

    There is a perception that automated irrigation systems can use more 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 based on the individual needs of plants and specific landscape areas. This enables the landscape or crops concerned to absorb water more efficiently, reducing the wastage of run-off which is a common problem that occurs when water is applied faster than plants and soils can absorb it.

    Controllers

    Indeed, controllers provide an easy way for users to adjust their irrigation system based on the needs of the environment. For example, during wet periods, a user’s water budget can be automatically adjusted down to 15% of its peak setting to reduce water usage by as much as 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 properly absorb to reduce run off.

    The controller can also calculate daily evapo-transpiration values and automatically adjust station run times to replace only the water needed by the plants. By adding an automatic shut-off device to controllers, such as a rain or soil moisture sensor, some 15-20% more water savings can be made.

    Sensors are available for both residential and commercial applications.

    Controllers can be linked to weather stations and selected controllers for both commercial and  now residential markets can also be web enabled with the addition of a communication cartridge and connected to the internet to benefit from internet weather forecasts to predict irrigation requirements.

    Other technology considerations

    In landscaping, water is often 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. In low water pressure situations, that use of a high efficiency irrigation pump to boost the pressure to peak efficiency, combined with pressure regulating system sprayheads, will ensure efficient and uniform irrigation coverage. Irrigation schedules will no longer have to run for longer periods to compensate for areas of weak coverage due to low pressure.

    Installation and maintenance

    Once a system has been properly designed and water conserving irrigation products and systems have been selected, proper installation and maintenance are essential. Employing a fully qualified irrigation contractor is recommended for the entire process and he will be able to demonstrate knowledge of all aspects of installation design and layout, as well as maintenance and repair procedures for irrigation systems.

    On-going maintenance programmes, whether conducted by third party irrigation professionals or by qualifed in-house maintenance managers, are essential for continuous conservation of water. Periodic monitoring is just as important as the design of an installation, 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.

    Summary

    Those engaged in the landscape industry including the manufacture, distribution and use of irrigation technologies are now working much more closely together. They are continuously developing and adopting planned irrigation design and maintenance practices, smart irrigation solutions and landscaping techniques.

    These all have the aim of conserving water and there is no doubt that water-efficient irrigation and the intelligent use of water represent the best immediate solution to the water crisis. Improved water delivery systems, recycling and more desalination plants are just as important, representing medium to longer term water conservation solutions.

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