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Issues from 1998
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Strategically reducing our potable water use

Words: Mr David Ashton - Photography: Mr Lachie Fairbairn and others

In recent years Scotch has made a major effort to reduce its dependence on potable water to maintain the beauty and lushness of its grounds and surroundings. This has resulted in more than halving Scotch’s use of mains water. But it is really just the beginning.

Late last year the bulldozers moved in on the McKendrick (soccer) Oval. Tonnes of soil were removed, and a 2.4 million litre tank for storing stormwater and reclaimed water was installed. Within weeks the project was completed, the tank covered with soil, and the lush surface of the oval restored with warm season Santa Ana couch grass.

       

Then, fortuitously, it rained in December. More than 70mm of rainfall ensured that the tank was filled almost to capacity. Although there was to be little if any rain for two months after that, Scotch could draw on the millions of litres locked away under the McKendrick Oval to water the Main Oval, also newly resurfaced with Santa Ana couch.

The 2.4 million litre tank under the McKendrick Oval is just one element of the school’s $3 million stormwater harvesting and irrigation reticulation master plan.

Scotch’s property manager, Bill Sciaretta, said approximately 200 metres of pipeline was bored from the James Forbes Academy around the Main Oval and down to the Rugby Oval to establish the stormwater diversion line to feed the new storage tank. ‘The tank actually contains more than 25,000 modules, each of which can hold 95 litres of water,’ Bill said. ‘It’s hard to imagine that an underground tank with the capacity of two and a half Olympic swimming pools now sits under the McKendrick Oval.’

The school also has extraction rights to six million litres of water from Gardiners Creek annually, to enhance its water storage capacity; and through the generosity of a school family, we have been fortunate to secure a further six million litres from Gardiners Creek each year.

Other water conservation measures the school has taken include replacing the Junior School Oval’s deteriorating grass surface with a synthetic surface, which will save about six million litres of water per annum (see ‘Synthetic surface helps beat drought’ in this issue).

Scotch Curator Michael Smith says resurfacing the Main and McKendrick Ovals has led to a 50 per cent reduction in water required to maintain these ovals during the summer months. He says that as well as its environmental benefit of requiring less water, the new Santa Ana surface is an excellent choice for sportsfields.

‘It has been used extensively in Victoria since 1980, and still rates better than later varieties for its excellent drought tolerance, high wear tolerance, shortness of dormancy and low nutritional requirements.’ Michael says during the winter when the new grasses are dormant, the quality and colour of the playing surfaces will be maintained by oversowing with cool season grass varieties such as rye grass.

The McKendrick Oval tank is only one element of the school’s $3 million stormwater harvesting and irrigation reticulation master plan, developed under the aegis of the School Council. Implemented over several years, the plan aims to allow Scotch to maintain its sports facilities and amenities while considerably reducing its draw on Melbourne’s potable water supplies.

Michael Smith says Scotch’s ultimate objective is simple. ‘It’s to use no mains water for irrigation on the grounds, and we are well on the way to achieving this outcome.’

Planning for stage two of the plan has begun. This stage will include the installation of a second major storage tank with a capacity of about three million litres, and resurfacing the Meares Oval with Santa Ana couch.

Scotch Bursar Ross Congleton says Scotch believes it is inappropriate to expend relatively large volumes of potable water on our grounds. ‘We are very conscious of the need to act as good community citizens’, he says.

To learn more about Scotch’s
sustainability program please
visit the website at www.scotch.vic.edu.au

Ross says the extent of any further reduction in potable water consumption is difficult to forecast, and will depend on achieving access to adequate sources of reclaimed water. ‘As mentioned, we have already achieved a 50 per cent reduction, but it has been at the expense of some distress to our grounds. So further sources of reclaimed water are considered necessary.’

Another source could be treated sewer water. Water extracted from nearby sewers could be treated and recycled for use in irrigating Scotch’s grounds. This and other methods of reclaiming and storing water will continue to be investigated as part of the ongoing master plan.

Mick Smith says he is often asked why we needed to change the grass on the Main Oval. ‘There are two main reasons. One is water conservation: the warm season grass on the oval will save around four million litres per annum. The other important reason is to provide a safe playing environment for our boys to enjoy.’ GS

Transformed—the McKendrick Soccer oval

               

Updated: Monday 24 June 2013