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Landscape irrigation auditing saves water and money The results of audits carried out on turf irrigation systems indicate that, in many situations, there are opportunities for substantial water and other cost savings. Landscape irrigation system auditors, with certification from the Irrigation Association of Australia, have carried out over a hundred audits since June 2004. Table 1 details the results of two audits carried out on ovals in Western Australia earlier this year by irrigation managers who were participating in the IAA Certified Irrigation Auditor-Landscape certification process. The table shows the plant water requirement (this is the water required to replace the water lost through evapo-transpiration) over an 8-day period for a warm season grass such as couch. The application efficiency, measured by Distribution Uniformity, of each system was measured using a catch can test and were found to be 58% for system A and 48% for system B. The impact of these inefficiencies is reflected in the irrigation water requirement data, which is the depth of irrigation required to supply the plant water requirement over the whole irrigated area. Because of the inefficiency of System A it is necessary to apply 241 mm of irrigation per 28-day period rather than 140 mm. Because System B is even more inefficient it is necessary to apply 292 mm instead of 187 mm. The table details the additional volume and cost of water resulting for these systems. Table 1 Irrigation system audit results.
In this case the two ovals were relatively small and are watered by irrigation systems with only five stations in each system. The cost savings that could be made by increasing the efficiency of the systems are $267 for each 28-day period for system A and $384 for each 28-day period for system B. Over a six-month irrigation season the cost savings would be about $1600 for System A and $2300 for System B. It is important to understand that the direct cost of the water is only part of the cost of non uniform watering. Table 1 details a plant water requirement of 5mm per day. For system A with a DU of 58% part of the system will only be receiving 2.9mm when the average receives 5mm. So to ensure that the whole area receives 5mm some parts of the oval will actually receive 8.6mm, resulting in some parts of the oval being over watered. In those places where the oval is over watered any fertiliser or pesticide applications are likely to be carried through the soil profile and end up below the root zone. All of this chemical will be wasted and could end up causing environmental damage if a drainage system carries excess irrigation water away. The energy costs of operating the systems also increase because the systems will be running for nearly twice as long as they would need to if the system was more uniform. The costs outlined above highlight the differences in cost between efficient and less efficient irrigation systems. Generally the design is the starting point for an efficient system but regular monitoring and maintenance is necessary to keep the system operating efficiently. The costs of not maintaining a system include extra water, extra energy and additional chemicals, all of which can be avoided. Our auditing services · Let us answer any auditing questions you have. · We can provide you with a quote to carry out an audit on your irrigation system · We can provide you with essential tools and products to complete and audit If you are looking for a qualified auditor near you or would like to become a qualified auditor look for them on the Irrigation Association of Australia’s webpage: http://www.irrigation.org.au/ci_auditor.html Here you can find information about Capabilities products,
the Hart Stick and the CapeAbility Catch Can.
There
is also information on
SPACE Pro, a
third party software package. Services Here you can find information about services provided by Capability and associates. |
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